new climate for conservation

8/14/2019 New Climate for Conservation

1/100

Dr. Jim Pojar

A New Climate for ConservationNature, Carbon and Climate Change in British Columbia


2/100

A N E W C L I M A T E F O R C O N S E R V A T I O N

2 | Nature, Carbon and Climate Change in British Columbia

Commissioned by the Working Group on Biodiversity, Forests and Climate, an alliance o ENGOs, including:

B.C. Spaces or NatureCanadian Parks and Wilderness SocietyDavid Suzuki FoundationForestEthics

Graphic design and production by Roger Handling, erra Firma Digital Arts.Cover photo credits: Paul Colangelo (main image); (top to bottom) Evgeny Kuzmenko, Sandra vom Stein, Robert Koopmans;

(people) Aaron Kohr.January 2010

Te Working Group on Biodiversity, Forests and Climate grateully acknowledges fnancial support rom theWilburorce Foundation, the Bullitt Foundation, the Real Estate Foundation o British Columbia, PatagoniaInc. and ides Canada Exchange Fund o ides Canada Foundation, in the preparation o this report.

Te Land rust Alliance o B.C.West Coast Environmental LawYellowstone to Yukon Conservation Initiative

CPAWS


3/100


Nature, Carbon and Climate Change in British Columbia | 3

Acknowledgements

Tis report was commissioned by the Working Group on Biodiversity, Forests and Climate, an alliance o

Environmental Non-governmental Organizations (ENGOs) including: B.C. Spaces or Nature, Canadian

Parks and Wilderness Society, David Suzuki Foundation, ForestEthics, Land rust Alliance o B.C., West

Coast Environmental Law, and Yellowstone to Yukon Conservation Initiative.

Forest Ecologist Dr. Jim Pojar, who prepared the report, has extensive proessional experience in applied

conservation biology, orest ecology, sustainable orest management, ecological land classifcation, and

conservation, with a wealth o feld experience throughout British Columbia.

Te hope is that this synthesis o scientifc inormation (on primarily terrestrial ecosystems) will be an

important contribution to the current rethinking o nature conservation and climate action planning in

British Columbia. Te author and reviewers acknowledge several areas that were not within the scope o

this project but would augment our current knowledge. For example, our comprehension o impacts to

biodiversity would be greatly enhanced by a deeper understanding and application o Indigenous Ecological

Knowledge in B.C. in collaboration with First Nations peoples. Other topics that were outside the scope o

the report, but that would be important parts o a comprehensive analysis, include: a socio-economic analysiso the implications o a carbon economy and orest carbon initiatives; a greater understanding o market

leakage rom conserving orests and reducing harvest levels; implications o genetically modifed organisms;

and the role o B.C.s ecosystems, including oceans, in the larger global climate scenarios. A separate executive

summary is available at http://www.orestethics.ca/new-climate-or-conservation-report.

Working Group on Biodiversity, Forests and Climate An Alliance of Environmental Non-governmental

Organizations:Candace Batycki, Director o Forest Programs, ForestEthics

Ric Careless, Executive Director, B.C. Spaces or Nature

Jessica Clogg, Executive Director and Senior Counsel, West Coast Environmental Law

Marlene Cummings, BC Forest Campaigner, ForestEthicsWendy Francis, Director o Conservation: Science and Action, Yellowstone to Yukon Conservation Initiative

Sheila Harrington, Executive Director, Land rust Alliance o British Columbia

Dr. Faisal Moola, Director o errestrial Conservation and Science Program, David Suzuki Foundation;

Adjunct Proessor, Faculty o Forestry, University o oronto

Chloe OLoughlin, Executive Director, Canadian Parks and Wilderness Society BC Chapter

Project Coordinator:

Marlene Cummings, ForestEthics

Editorial Coordinator:

Dr. Briony Penn, Briony Penn Associates


4/100



Scientifc Reviewers:

Dr. Sally Aitken, Proessor o Forest Genetics; and Director, Centre or Forest Conservation Genetics, UBCDennis Demarchi, Consulting Wildlie BiologistMike Fenger, RP Forester, Principal, Mike Fenger and Associates Ltd.Dr. Lara J. Hansen, Chie Scientist and Executive Director, EcoAdaptMark E. Harmon, Richardson Chair and Proessor, Department o Forest Ecosystems and Society, Oregon

State University

Dr. Richard Hebda, Curator, Botany and Earth History, Royal B.C. MuseumDr. Rachel Holt, Principal, Veridian Ecological Consulting LimitedSusan Pinkus, Sta Scientist, Ecojustice CanadaDr. Suzanne Simard, Proessor o Forest Ecology, UBC Faculty o Forestry

Additional Scientifc Advice rom:

Pierre Iachetti, Director o Conservation Science & Planning, Nature Conservancy o Canada, BC RegionDr. Beverly Law, Proessor o Global Change Forest Science, Oregon State UniversityDr. Paul Paquet, Senior Scientist, Raincoast Foundation, BC; and Proessor o Environmental Design,

University o Calgary

Legal and Policy Reviewers:

Keith Ferguson, Sta Lawyer, Ecojustice CanadaJohnny Mikes, Planning Advisor, Canadian Parks and Wilderness SocietySean Nixon, Lawyer, Woodward & CompanyDevon Page, Executive Director, Ecojustice Canada

Additional Research and Technical Advice:

Gregory Kehm, Program Director, Ecotrust CanadaVeronica Lo, Marine Conservation Planning Coordinator, Canadian Parks and Wilderness Society

BC ChapterDave Neads, Director, Bioenergy Program, BC Spaces or NatureBob Peart, past Executive Director, Canadian Parks and Wilderness Society BC ChapterDr. Briony Penn, Briony Penn Associates

Editorial Assistance on Executive Summary rom:

Dr. Rachel Holt, Veridian Ecological Consulting Limited

Copy Editing by:

Joe Kadi, Editorial Consultant

Graphic Design:

Roger Handling, Creative Director, erra Firma Digital Arts


5/100



Table of Contents

able o Contents ............................................................................. .......................................................................................... 5

Introduction ...............................................................................................................................................................................7

PART 1: BIODIVERSITY, CLIMATE CHANGE AND ADAPTATION ................................................................8

1.1 Importance o British Columbias Biodiversity ..............................................................................................................8

1.1.1 Summary o Biodiversity in B.C. ........................................................................................................................ 101.2 Climate Change Underway .............................................................................................................................................11

1.2.1 Historic and Recent Climate Change in British Columbia ............................................................................... 13

1.2.2 Projected Future Climate Change ....................................................................................................................... 13

1.2.3 Summary o Climate Change Underway ........................................................................................................... 15

1.3 Impacts o Climate Change on B.C.s Biological Diversity ....................................................... ..................................15

1.3.1 Review o Changes in Ecological Processes, Ecosystems and Species ................................................................ 15

1.3.2 Summary o Climate Change Impacts ............................................................................................................... 16

1.4 Projected Impacts o Climate Change on B.C.s Biological Diversity .......................................................................16

1.5 Future Ecosystem Responses ..........................................................................................................................................16

1.5.1 Changes to errestrial Biogeoclimatic Zones ..................................................................................................... 18

1.5.2 Natural Disturbances .......................................................................................................................................... 211.5.3 Ecosystem Productivity ........................................................................................................................................ 23

1.5.4 Freshwater Aquatic Ecosystems .......................................................................................................................... 24

1.5.5 Summary o Future Ecosystem Responses .......................................................................................................... 25

1.6 Future Species Responses ................................................................................................................................................26

1.6.1 Species o Most Concern ...................................................................................................................................... 26

1.6.2 Specialised Species ................................................................................................................................................ 28

1.6.3 Keystone Species ................................................................................................................................................... 28

1.6.4 Signifcance o rees as Foundation Species ....................................................................................................... 29

1.6.5 Importance o Step-wise Jumps and Long Distance Dispersal or ree Species ............................................... 30

1.6.6 Summary o Future Species Response ................................................................................................................. 30

1.7 Future Genetic Responses ...............................................................................................................................................311.7.1 Clinal and Racial Variation ................................................................................................................................ 31

1.7.2 Te Ecological Teatre and the Evolutionary Play: B.C. ree Species on Stage .............................................. 32

1.7.3 Genetic Dri and Natural Selection in rees ..................................................................................................... 33

1.7.4 Adaptive Capacity o rees .................................................................................................................................. 33

1.7.5 Genetic Responses in Other Species .................................................................................................................... 35

1.7.6 Isolated Populations ............................................................................................................................................. 36

1.7.7 Cryptic Species ..................................................................................................................................................... 37

1.7.8 Hybridisation ....................................................................................................................................................... 38

1.7.9 Summary o Future Genetic Responses .............................................................................................................. 38

1.8 Resilience and Ecological Adaptation ...........................................................................................................................39

1.8.1 Moderated Microclimates .................................................................................................................................... 391.8.2 More Biodiversity? ............................................................................................................................................... 39

1.8.3 Species Adaptation, Migration and Survival ..................................................................................................... 41

1.8.4 Facilitated Migration ........................................................................................................................................... 43

1.8.5 Summary o Resilience and Ecological Adaptation ........................................................................................... 43


6/100



1.9 Planning or Ecological Adaptation ...............................................................................................................................45

1.9.1 Protected Areas .................................................................................................................................................... 45

1.9.2 How Much is Enough? ......................................................................................................................................... 46

1.9.3 Beyond Preservation: Managing the Matrix ...................................................................................................... 47

1.9.4 Status o Conservation Legislation in B.C. ......................................................................................................... 47

1.9.5 Managing the Forest Matrix ............................................................................................................................... 48

1.9.6 Summary o Planning or Ecological Adaptation .............................................................................................. 50

PART 2: BIODIVERSITY, CLIMATE CHANGE AND MITIGATION ...............................................................51

2.1 Importance o Ecological Mitigation .............................................................................................................................51

2.2 Natural Capital and Ecosystem Services .......................................................................................................................51

2.2.1 Summary o Natural Capital and Ecosystem Services ...................................................................................... 52

2.3 Role o Ecosystems in Climate Change Mitigation .....................................................................................................53

2.3.1 Forested Ecosystems o B.C. ................................................................................................................................. 53

2.3.2 Non-Forested, Permarost and Oceanic Ecosystems .......................................................................................... 54

2.3.3 International Recognition o Natures Role......................................................................................................... 56

2.3.4 Summary o Role o Ecosystems in Climate Change Mitigation ...................................................................... 57

2.4 Changing Policy in Forest/Carbon Mitigation in B.C. ...............................................................................................58

2.4.1 Summary o Changing Policy in Forest/Carbon Mitigation in B.C. ................................................................ 59

2.5 Emerging Research into Forest/Carbon Dynamics ....................................................................................................59

2.5.1 Young Forests versus Old Forests? ....................................................................................................................... 59

2.5.2 A Standing ree or Wood Products? ................................................................................................................... 60

2.5.3 Are Forests Sinks or Sources? ............................................................................................................................... 62

2.5.4 Bioenergy: Substitution or Source? ..................................................................................................................... 64

2.5.5 Summary o Emerging Research into Forest/Carbon Dynamics ...................................................................... 65

2.6 Current Forest/Carbon Mitigation Pilots .....................................................................................................................66

2.6.1 Summary o Forest/Carbon Mitigation Pilots ................................................................................................... 68

PART 3: PRIORITY RECOMMENDATIONS .......................................................................................................70

1. Integrate Nature Conservation Strategies with Climate Action Strategies ................................................................702. Broaden Core Protected Areas into a Climate Conservation Network .....................................................................71

3. Introduce New ools, Legislation and Incentives ........................................................................ ..................................72

4. Provide Incentives or Stewardship in Every Sector ......................................................................................................73

5. ake the Lead on Carbon/Biodiversity Valuation .........................................................................................................73

6. Establish the Principle that Humans are Part o Nature and

our Survival is Intertwined with Natures Survival. .........................................................................................................74

APPENDIX: GLOSSARY ........................................................................................................................................75

Endnotes ...................................................................................................................................................................................79


7/100



Introduction

A New Climate or Conservation: Nature, Carbon and Climate Change in British Columbia explores the role onature conservation in a climate action strategy or ecological adaptation (Part 1) and ecological mitigation(Part 2), with the key recommendation to develop a comprehensive and integrated Nature Conservation andClimate Action Strategy or the Province o British Columbia (Part 3):

Part 1 presents available science on current climate-change projections, and present and uture impacts oclimate change to ecosystems, species, genotypes, and the processes linking them. Te review ocusesprimarily on orested systems, and also addresses non-orest and aquatic systems. Ecosystem resilienceand adaptation options, in relation to climate change, are outlined. Current thinking in conservationscience is then summarised in light o external pressures. B.C.s existing conservation planning and

orestry management are reviewed in terms o their ability to respond to the challenges o climatechange.

Part 2 summarises literature on natural capital, ecosystem services and the role o ecosystems in climate-change mitigation. Variations in carbon sequestration and storage in dierent ecosystems are discussedand research gaps in orest carbon dynamics are identifed. Current opportunities or an oset marketthrough carbon activities such as avoided degradation, ecological restoration and improved orestmanagement are also explored, in light o recent pilot projects in B.C.

Part 3 integrates the fndings rom Part 1 and Part 2 in a central recommendationto develop acomprehensive and integrated provincial Nature Conservation and Climate Action Strategy. o be

e cient, this strategy must combine nature conservation and carbon/climate management planning.o be eective, it must embrace the undamental role o conserving natural ecosystems or adaptationand mitigation o climate change, and or natures many other ecosystem services, which underpinsustainable options or current and uture generations.

PhotoAaronWard


8/100


9/100



B.C. also has extensive grasslands, wetlands, and alplands. In the ruggedly mountainous regions with sharpclimatic gradients, the rate o change in species composition (gamma diversity) accelerates rapidly rom lowto high elevations (ocean through orests to alpine in many cases), rom south to north, and rom west to east,rom the wet coast to the dry interior. And all this terrestrial ecosystem diversity is supplemented, enhanced,and connected by the aquatic realm, with its variety and range o reshwater and marine habitats.

Te ecological diversity o B.C. is globally signifcant: 16 biogeoclimatic zones are defned by the

Biogeoclimatic Ecosystem Classifcation (Figure. 1), each with numerous diverse habitats, dry to wet, orestedand/or non-orested. wo o these zones are not ound anywhere else in the world.2

Figure 1. Biogeoclimatic

zones o British Columbia.wo additional alpine zonesare not shown. Ministry o

Forests and Range, 2006.

Not surprisingly, B.C. is the most diverse province or territory in Canada, physically and ecologically, andhas the highest number o native species. For example, it is home to 76 percent o our nations bird species,70 percent o its reshwater fsh, and 60 percent o its evergreen trees. Tree-quarters o Canadas mammalspecies are ound in B.C.; 24 o these occur only in this province. Te number o at-risk species in theprovince is also high compared to other jurisdictions o similar latitudes.3

Te province currently has global stewardship responsibility or a large proportion o the worlds ancienttemperate rainorests, wild rivers, salmon and rich marine ecosystems. By hosting a large portion o theworld population or range o some species, such as mountain goat (Oreamnos americanus) and sooty grouse(Dendragapus obscurus uliginosus), B.C. has a global responsibility or their conservation. Te province has

also become a globally important reuge or ormerly common or widespread species, like grizzly bear ( Ursusarctos horribilis) and wolverine (Gulo gulo). Tus, B.C. has increased international responsibility or speciesincluding several high profle carnivores and ungulatesonce widespread across North America but whoseranges have collapsed towards the province.4

Tis concept o global responsibility applies beyond species. B.C. has globally signifcant biophysical diversityand landscape complexity, as well as internationally signifcant, dynamic systems like the intact large-mammal predator-prey and wild river-salmon-grizzly bear-orest systems.


10/100


11/100



1.2 Climate Change Underway

Te Fourth Assessment Report o the Intergovernmental Panel on Climate Change8 asserts with confdencethat most o the recent global climate change is due to human activities; the burning o ossil uels,deorestation, and agriculture have caused increased releases o greenhouse gases, including carbon dioxide(CO

2), methane, and nitrous oxide. Summaries o the evidence or these conclusions can be ound in

other publications. Good discussions o climate change and its implications in British Columbia are alsoavailable.9,10,11,12,13,14 Most recently, the role o emissions rom deorestation and land degradation has been

better understood by the international community,15

with a corresponding recognition that reducing theseemissions is a key component o an integrated climate action strategy.16

Although the Earths climate changes constantly, the change is not constant; it varies in rate and amplitude.Postglacial climatic history is dealt with extensively in various articles; a short summary is included here. 17Fieen thousand years ago, most o British Columbia was covered by ice. Te ice sheets melted when theclimate warmed between about 13,000 and 10,000 years ago.18 Deglaciation was accompanied with andollowed by rapid warming, then a warm and dry interval, ollowed by warm moist conditions. About4,500 years ago, B.C. entered a relatively cool interval that persisted until very recently. Embedded in thesemillennial trends were shorter periods o warming and cooling, drying and wetting.

Te Medieval Warm Period (ca 900 to1500) was ollowed by the Little Ice Age (1500 to 1850). Climaticoscillations such as the El Nio-Southern Oscillation and the Pacifc Decadal Oscillation also contributeto the variability o B.C.s climate when considering several-year to several-decade intervals. Te overallNorthern Hemisphere trend through these oscillations over the past 1,000 years was slow cooling andthen rapid warming, starting about 100 years ago, corresponding with rising industrialization and majorchanges in land use. Observed warming trends in the last century and predicted trends in the uture willhave increasingly large impacts on British Columbias biodiversity, ecosystem services, and greenhouse gasemissions.19

Global warming and the accompanying changes in precipitation patterns are expected to continue throughthis century as greenhouse gas concentrations increase.20 Te amplitude o expected change cannot

Salmon are sensitive to temperature change throughout their lie c ycle. Photo Robert Koopmans


12/100



be predicted with precision because o uncertainty about the success o the international communitysgreenhouse gas reduction eorts. Inevitable errors associated with model projections exacerbate thisuncertainty. Initial projections, using several General Circulation Models (GCMs) to provide several dierentemission scenarios, placed some boundaries around possible uture outcomes (Figure 2).

Figure 2. Simulated change in global mean

temperature rom the 1980-1999 mean value. From

1900 to 2000, the simulation uses past greenhouse

gas emissions and natural actors (black line); rom

2000 to 2100 it uses selected emissions scenarios

(red, green, and dark blue lines). Te orange line

indicates the efect o an immediate total cut in

emissions. Shading around each line represents

1 SD on a range o annual means rom 16 to 21

GCMs (adapted rom IPCC 2007). Retrieved rom

Spittlehouse (2008).21

Recent observations reported by the scientifc community at the UN climate talks in Copenhagen, March2009, confrmed that given high rates o observed emissions, the worst-case IPCC scenario trajectories (oreven worse) are being realized. For many key parameters, the climate system is already moving beyond thepatterns o natural variability within which our society and economy have developed and thrived. Teseparameters include global mean surace temperature, sea-level rise, ocean and ice sheet dynamics, ocean

acidifcation, and extreme climatic events. Tere is a signifcant risk that many o the trends will accelerate,leading to an increasing risk o abrupt or irreversible climatic shis. 22

1.2.1 Historic and Recent Climate Change in British Columbia

Climatic trends over both the past century and more recent decades indicate major changes in temperatureand precipitation in British Columbia, changes that varied by season and by region. Overall, recent measuredchanges in B.C.s climate are consistent with, or greater than, predictions rom global climate models,confrming the worst case scenarios identifed in the March climate talks in Copenhagen:23,24

Te province has warmed up, with winters warming up more than summers. Te rost-ree period lengthened by 21 days between 1950 and 2004.25

Annual precipitation increased by about 22 percent on average over the past 100 years, with signifcantseasonal and regional variation. Most o the province experienced reduced winter precipitation andincreased summer precipitation over the past 50 years. On the coast, the wet winter season has becomeshorter but wetter, the dry summer season drier and longer.

Water temperatures in rivers are rising. For example, peak summer temperatures on the Fraser Riversmain stem have risen 1.5C since 1940.26

Recent warming has probably increased the requency o large landslides in northern B.C., due in part tomelting permarost and to debuttressing o rock slopes adjacent to retreating glaciers.27

Medium reduction in emissions A1B

Minimal reduction in emissions A2

Large reduction in emissions B1

Total cut in emissions now

Historic conditions


13/100



1.2.2 Projected Future Climate Change

Te initial modelling o the United Nations Intergovernmental Panel on Climate Change (IPCC) suggesteda rise in average surace temperature o Earth in the range o 1.1 to 6.4 oC by 2100.28 Given that the worst-case scenarios may occur, it is clear that the resulting uture climates will be radically dierent than what hasoccurred in the last 750,000 years.29 Te problem is exacerbated in northwestern North America becausethe rate o change increases rom the equator to the north pole.30 Climate models project a persistent eect.

Excess greenhouse gases already in the atmosphere will continue to drive climate change and its impacts orcenturies to come.

Te ollowing climate change projections or BritishColumbia were made prior to the March talks inCopenhagen31, and it is clear that the higher endvalues (worst-case scenarios) are more representativeo the trend. Generally, B.C.s climate over the next100 years will become even warmer than in the last100 years, and the rate o warming will be aster.Associated with this warming will be changes inprecipitation regimes and an increased requencyo extreme temperature and precipitation events.32Overall, as this century progresses, B.C. can expectwarmer and wetter winters especially in the north,progressively warmer and probably drier summersin at least the southern hal o the province, andinitially cooler but ultimately warmer and probablywetter summers in much o the northern hal othe province. Winters in general will be wetteracross British Columbia, with a greater increase inprecipitation in the north, and in many areas theextra precipitation likely will all as rain rather than snow.33

Future climate change scenarios represent a range o possible climates rather than specifc narrowpredictions. Moreover, site-specifc projections o climate change and its impacts in British Columbia areinherently imprecise because the province has such complex topography and climatic processes, and suchsharp ecological boundaries. Nonetheless, scenarios based on the best inormation currently availablesuggest that without dramatic changes in human behaviour, B.C. should anticipate the worst-case scenarios.Projections o temperature changes have greater certainty than projections o precipitation changes amongthe currently available climate models.34 Figures 3 and 4 depict sets o temperature and precipitationprojections, summarized below:

Temperature

Mean annual temperatures warming by 3 to 5oC by 2100. January minimums and July maximums rising by 5 to 10oC by 2080. Winters warming aster than summers. Lakes and rivers increasingly becoming ice-ree earlier in the spring, and at least the larger bodies o

water reezing over later in the winter.

Precipitation

B.C. precipitation up 9 to 18 percent by 2100, with most o the increase generally occuring in winter. Alsothere will be decreasing summer precipitation in the southern hal o the province.

Declining snowpack, in most parts o the province.

While some species, such as mule deer, can disperse and move long

distances quickly, many species will not be able to relocate so readily as

ecosystems change. Photo Tom Tietz


14/100



Changing snowpack, with more requent thaw-reeze events in winter. Tis will result in denser snow

with more crusts and icy layers, and will aect wildlie survival.

Declining summer stream ows in many snow-dominated systems, resulting in warmer water. Glacier-

ed rivers will experience the opposite, or as long as the ice lasts.

Amplifcation o the hydrological cycle, maniested by increased cloudiness, latent heat uxes, and more

requent climate extremes.35 Tis will increase the risk o drought, heat waves, and intense precipitation

events and ooding.36

Figure 3. Mean annual

temperatures for British

Columbia: past normals

(1961-1990) and projections for

2020s, 2050s, and 2080s, for the

middle range A2 scenario from

the Canadian Global Climate

Model version 2 (CGCM2).

Retrieved from Spittlehouse

(2008).37

Figure 4. Annual precipitation

for British Columbia: 1961-1990

baseline & projected percentage

changes from baseline for

2020s, 2050s and 2080s, for A2

scenario of CGCM2. Retrieved

from Spittlehouse (2008).


15/100



1.2.3 Summary of Climate Change Underway

Global climate change is underway. Signifcant warming has already occurred on land and in water, andthe continuing changes are expected to happen aster and be more pronounced in British Columbia thanthe global average. British Columbias climate over the next 100 years will become even warmer with meanannual temperatures warming by 3 to 5oC i current trends continue unabated. Tere will be more extremeweather events with increasing intensity o storms, oods, wildfres and drought. As this century progresses,

B.C. can continue to expect warmer and wetter winters especially in the north, progressively warmer anddrier summers in the southern hal o the province, and wetter initially cooler but ultimately warmersummers in much o the northern hal o the province.

1.3 Impacts of Climate Change on B.C.s Biological Diversity

Climate change is already signifcantly impacting healthy ecosystems in British Columbia, and will likelycause more dire consequences or ragmented or degraded ecosystems. Te changing climate is stimulatingspecies-level changes in range and abundance, lie cycle and behaviour, and genotypes. Globally there isevidence that some species are already evolving (adapting genetically), 38 or expanding their range polewardsor upwards in elevation39, or adjusting migration,40 breeding,41 or owering42 times in response to climate

warming. Species-level changes are resulting in changes to ecosystems.

43

Tese and other inter-relatedchanges to ecological processes, ecosystems and species are also happening in British Columbia.

1.3.1 Review of Changes in Ecological Processes, Ecosystems and Species

Warmer winters and longer growing seasons, as well as suppression o orest fres, have been linked tothe current vast mountain pine beetle (Dendroctonus ponderosae) epidemic.44,45,46 ,47 Te intensifcationo ungal needle blight (Dothistromaseptosporum)48on lodgepole pine49 can also be attributed in part toclimate change.

Native willows are under attack by an introduced insect pest, the willow stem borer (Cryptorhynchuslapathi),50,51 a Eurasian weevil that has spread widely in southern and now central B.C.especially in thepast 30 yearsand is heading north along highways and logging roads. Te recent rapid spread appears

to be related to climate warming. Attacked willows tend to suer repeated attacks; the weevil populationbuilds up in individual stems and then spreads to adjacent willows. More than 75 percent o the willowsin some areas have been attacked. Ecosystem consequences are unknown but willows are used by manydierent animal species and play key ecological roles in wetlands, riparian habitats, and upland orest andshrublands.

Extensive die-back and changing phenology o trembling aspen (Populus tremuloides) and paper birch(Betula papyriera) in the southern interior52 are having an impact on the ecosystems they inhabit.53

Yellow-cedar (Chamaecyparis nootkatensis) dieback has a climate change component. Te decline oyellow-cedar in Southeast Alaska and on B.C.s north coast appears to be due to a type o reezing injuryto roots. Susceptibility o the tree roots to reezing damage is related to decreased protective snowpackand premature dehardening in the spring.54,55,56 Tis could be an example o a general phenomenon:climate warming paradoxically may actually increase the risk o rost damage to plants.57 Mild wintersand warm early springs can induce premature plant development, resulting in exposure o tender parts tosubsequent late-season rosts, as evidently happened in spring 2007 in the eastern USA.58

Dieback o western redcedar (Tuja plicata) has recently been reported rom the south coast, especiallyon the east side o Vancouver Islandpresumably because o increasing drought stress.59

Populations o eight bird species, including the common loon (Gavia immer), two sur scoter species(Melanitta usca and M. perspicillata), sandhill crane (Grus canadensis), Wilsons phalarope (Phalaropustricolor), Lewis woodpecker (Melanerpes lewis), Swainsons thrush (Catharus ustulatus), and yellow


16/100



warbler (Dendroica petechia), were ound to have earlier arrivals, later departures, and extended rangesnorthward.60

Warmer, wetter springs in west central B.C. could be at least partly responsible or reduced nest areareoccupancy and breeding success o goshawks (Accipter gentilis). Increased precipitation is linked to adecrease in prey abundance, and warmer spring temperatures are associated with high rates o mortalityas a result o attacks on nestlings by black ies.61

Recent reduction in populations o Fraser River sockeye salmon (Oncorhynchus nerka) has been linked

in part to increasing river temperatures and changes to the ow regime.62 In the hot, dry, low-owsummer o 2004, Fraser River temperatures reached 20-21oC, about our degrees warmer than normaland into the lethal range or sockeye.63 Soon salmon may be unable to migrate through the Fraser due tooverly warm waters.

In October 2008, many populations o Pacifc sockeye salmon were placed on the IUCN Global Red Listo Treatened Species. One-quarter o the worlds sockeye salmon populations are at risk o extinction,including 10 B.C. runs. Key threats to threatened/endangered populations included mixed stock fshingleading to overfshing o smaller, less productive stocks, negative eects o hatcheries and artifcialspawning habitat, and changing river and ocean conditions that are likely linked to global climatechange, expressed in poor marine survival rates and increased incidence o disease in adult spawners.64

Earlier snow melt, warmer temperatures, and more requent drought stress have created a longer freseason in much o inland western North America, resulting in an increase in the number, size, andintensity o wildfres.65,66,67

B.C. is experiencing more extreme events in general, with increased damage rom storms, oods, erosion,droughts, wildfres, and more requent and extensive outbreaks o pests such as bark beetles, needle andlea diseases, and deoliating insects.

1.3.2 Summary of Climate Change Impacts

Climate change is already signifcantly impacting healthy ecosystems in British Columbia, and will likelycause more dire consequences or ragmented or degraded ecosystems. Changes in species range andabundance, lie cycle and behaviour, survival rates and genotypes have all been detected and have ongoing

eects on ecosystem structure and unction. Impacts have occurred at all scales, rom the dramatic impacts omountain pine beetle populations on vast areas o orests, to dieback o single species. Other types o change,such as the arrival/departure dates o migrating species, and impacts on insects and the ood webs theysupport, are all being witnessed.

1.4 Projected Impacts of Climate Change on B.C.s BiologicalDiversity

Climate is the chie determinant o the distribution o species and the nature and character o ecosystems,and thus is a key driver o biodiversity. Over at least the past 4,000 to 4,500 years, British Columbia has hada relatively stable climate, leading to the current pattern o ecosystems.68 Te anticipated impacts o climate

instability and change on B.C.s biodiversity are diverse, complex and not well understood. Figure 5 presentsa good ramework or thinking about how and why biodiversity will be aected and could respond, atecosystem, species, and genetic levels.

1.5 Future Ecosystem Responses

Climate largely determines the nature and distribution o terrestrial species and ecosystems, and throughits eects on the water cycle also plays a major role in reshwater aquatic ecosystems. Climate change isalready driving worldwide ecosystem change in structure (vegetation and species composition), unction


17/100



(productivity, decomposition, water and nutrient cycling), processes (disturbance regimes, successionalpathways and hydrological regimes), and distribution.70,71 Future responses o B.C. ecosystems will becomplex, and are di cult to predict because they will reect the combined eects o changing climate, land-and resource-use activities, and invasive species.

wo principles should guide the interpretation o projected ecosystem trends and impacts:

1. Ecosystems do not migrate, species do.

Ecosystems will not move in toto to more northerly latitudes or aspects, or upward to newly suitable climateenvelopes. Ecosystem change will result rom changes in distribution at the species level. Existing ecosystemswill lose some species, gain others, and experience changes in abundance and dominance o the species thatpersist. Species are responding individualistically to environmental change. Some species will stay put andtheir populations will either wax or wane depending on changing circumstances. Other species will move, ithey can, to suitable habitats elsewhere, and will reassemble most likely in dierent combinations, includingsome novel ones. Some species will move in close concert; or example, hosts and their parasites, and preyand their specialized predators. Some close partners, like owering plants and their insect pollinators, or treesand ectomycorrhizal ungi, could become at least temporarily decoupled during long-distance migrations.Weedy ectomycorrhizal ungi, that might fll vacated niches, can be parasitic and acilitate the invasion oexotic weedy plants. New arrivals will interact with persisting species, and with exotic immigrants, to createnew ecosystems with new structures and unctions.

2. Most species cannot move fast enough to keep up with the projected changes.Te potential geographic range, or potential niche, o many species will shi markedly or expand greatly,but species that migrate slowly, like many o our trees, will need decades and probably centuries to moveaccordingly or to realize their niche.72 Long-distance dispersal will play a key role, as it has in the past. 73Species with poor dispersal capabilities, like ightless beetles, could ail to move quickly enough to survive atthe local level. Species whose potential geographic range shrinks could ultimately disappear i reproductiveindividuals die-oen masse (perhaps done in by a pathogen or an extreme disturbance or weather event) andenvironmental conditions are no longer suitable or their progeny or younger generations.

I the uture climate turns out to be an analogue o the relatively recent pastthe Xerothermic Interval o the

Figure 5. Conceptual ramework o climate change impacts on biodiversity. Retrieved rom CompassResource Management (2007).69


18/100



Holocene (between 10,000 and 6,000 years ago)when climates were 2 to 3oC warmer than at present, wecan expect some general vegetation trends toward conditions that prevailed at that time. Increases in weedy,drought-tolerant, and alkali-tolerant species, and decreases in moisture-loving and acid-tolerant species canbe expected74at least in southern B.C., where the climate will probably become drier as well as warmer andwhere the recent ossil record is airly well documented.75,76

1.5.1 Changes to Terrestrial Biogeoclimatic ZonesChanges to B.C.s ecological (biogeoclimatic) zones were frst projected by Hebda77 in 1997, more recently byHamann and Wang78 in 2006 (Fig. 6), and in the most recent dra analysis by Wang, Campbell and Aitken or2009.79 Climate envelope modelling shows the uture climatic niche o these dierent biogeoclimatic zones,not necessarily where species or ecosystems will be in the uture. Te most recent projections were done usingbest, intermediate and worst-case scenarios. As previously indicated, the worst-case scenarios are becomingthe most likely (3 to 5C in 70 to100 years), 'orcing' a shi o todays ecological zones (or rather, the climateenvelopes or such zones) a predicted 900 to 1500 m up in elevation and 450 to 750 km north. Te rate oprojected climate envelope shis' is estimated to be at least 40 km per decade. Suitable habitats will shi tooast or many species to keep up, or to compensate through dispersal and migration.

General predicted changes in the zonal climate envelopes include the ollowing: A general shi o zones rom the southern to the northern hal o B.C. A major expansion northward and upslope o dry non-orest (grasslands, shrub-steppe) and dry orest

zones (especially in the interior but also on the south coast). A massive expansion o moist coastal and interior conier orest zones upslope and north at the expense

o subalpine and sub-boreal spruce zones. A major decline in cordilleran boreal (spruce) zones in central and northern B.C. A near disappearance o northern subalpine/subarctic spruce-willow-birch bioclimates. A wide-ranging change in wetlands and aquatic ecosystems because o warmer water and changes in

hydrology related to decreased snowpack and shrinking glaciers. A shrinking o alpine tundra ecosystems and disappearance o alpine islands as woody ecosystems

(subalpine orests and shrublands) shi up in elevation. Some o the worst-case scenarios projectsubalpine conditions into much o the provinces alpine environment.

Large diebacks o trees, including urther diebacks o aspen, paper birch, ponderosa pine (Pinusponderosa), and whitebark pine (Pinus albicaulis), are expected due to drought and drought-acilitatedinsect, disease and fre damage.80

Dramatic expansions are indicated or the potential area o the Interior Cedar-Hemlock (ICH), Bunchgrass(BG), Ponderosa Pine (PP), Interior Douglas-fr (IDF), and Coastal Douglas-fr (CDF) zones. 82,83,84 TeEngelmann Spruce-Subalpine Fir (ESSF), Ponderosa Pine, and Interior Douglas-fr bioclimates will probablyexhibit the largest northward shis. Major declines are projected or the climate envelopes o the Alpineundra (A), Mountain Hemlock (MH), Montane Spruce (MS), Sub-Boreal Spruce (SBS), Boreal White

and Black Spruce (BWBS), and Spruce-Willow-Birch (SWB) zones.85,86

Te largest areal changes in climateenvelopes are projected or the ICH zone, which may double in size, and or the A and SWB zones, whichmay decrease by more than 90 percent.

Given these projections, the ecological and species range adjustments suggested by models will take manydecades i not centuries Te rates o migration and spread o the species required or such large expansionsover such great distance prohibit anything like the modern zones to develop in this interval. ransientecosystems o undetermined composition must be expected. Te character o these will likely be mediatedby pest outbreaks and fre.87 Such landscape-scale disturbances and extreme events like summer droughts,spring rosts, ferce storms and oods could be the determining actors.


19/100



Other potential changes to B.C.s ecosystems In northern B.C. it is more likely that subalpine shrublands (buckbrush) rather than orest will occupy

what currently is the lower alpine zoneas is already happening in the tundra o the north slope o

Alaska/Brooks Range88partly because the shrubs have shorter generation times, can reproduce through

suckers, and can migrate aster than conierous trees.

Forest composition (tree and understory species, including bryophytes and lichens on the orest oor)

will change signifcantly. Expect an expansion o dry orests in the southern and central interior, with

moister warmer orests in the north.

Te Alpine bioclimate is expected to diminish throughout the province although this trend will probably

be geographically idiosyncratic, not monolithic.89

Wetlands are physically constrained systems, sensitive to changes in hydrology, geomorphology, and

nutrient budget, and in most o the province are patchy and insular in distribution. Consequently they

are vulnerable to climate change.90 Fossil studies suggest that shallow interior wetlands, especially o

climates that are already dry, could dry up more.91

Wetlands o cool moist climates and stable hydrology, such as bogs, are likely to be negatively impacted.

Marshes and rich ens with uctuating water tables and higher levels o nutrients are more likely to

persist.92 Changes in wetlands will aect not only obligate wetland specieslike waterlilies, dragonies

and muskratsbut also will have major consequences or the breeding and migration o birds. 93

Te climate envelope o the now nearly continuous grasslands o southern interior B.C. could expand

substantially, throughout valley bottoms and up lower slopes, perhaps as ar north as Quesnel. 94,95,96

Figure 6. Potential shifs in

distribution by 2025, 2055

and 2085 o the existing

climate envelopes o British

Columbias biogeoclimatic

zones. Changes projected by

modelling the contemporaryclimate parameters o the

zones in terms o predictions

under an average climate

change scenario (CGCM1gax).

Retrieved rom Hamann and

Wang (2006).81 Te updated

Wang, Campbell and Aitken

maps were not available at

time o printing.


20/100



But they will probably be mongrel or weedy grasslands, inested with alien invasive species, as many

contemporary grasslands already are in southern B.C. In contrast, boreal grasslands could be at high risk o decline in wetter warmer climates, unless increasing

temperatures overwhelm increasing precipitation. Tese grasslands are already rare in the landscape andare currently being invaded by woody vegetation. Perhaps they will persist only on the driest south-acingsites, and maybe only i humans augment the woody-plant-eating activities o beaver (Castor canadensis),moose (Alces alces), Rocky Mountain elk (Cervus elaphus nelsoni), mule deer (Odocoileus hemionushemionus) and Stones sheep with prescribed fre. It is uncertain as to what will happen in northern B.C.to the mesic subalpine grasslands o high wide valleys with double treelines. Tey too could decline ishrubs (willows , Salix spp., and shrub birch, Betula nana) expand, but it could remain cold enough at highelevations to maintain the cold air ponding that is partly responsible or such patterns.

Province-wide, 40 to 60 percent o B.C.s glaciers will disappear and others will diminish greatly, leaving

behind big areas o deglaciated terrain as resh substrate or colonisation and ecological succession.Succession and community assembly will be a stochastic-deterministic process. Some outcomes will bealong the lines o those that have already been documented97,98,99,100 but others will probably be novel anddi cult to predict.

Permarost melting in northern peatlands will lead to accelerated decompositions o deep carbondeposits with large positive eedbacks to atmospheric CO

2.101

Very little is known about impacts o climate change on soils in B.C. Soils are living systems, with argreater species diversity than aboveground, and soil biology will likely present an important limitation toplant migration. Tere is growing evidence that changes in soil biology can cause ecosystems to collapseto an alternative regime that will hinder migration o species (other than weeds.)102

More trophic mismatches (that is, decoupling o species and ecosystem processes) could develop as plant

phenology advances with a warming climate. For example, herbivores (including large ungulates) currentlymay base their reproductive cycles or seasonal migrations on day-length, while vegetation emerges in thespring more as a consequence o local temperatures. As local temperatures increase and vegetation leasout earlier in the season, successul herbivore reproduction might declineas it evidently has in Arcticcaribou.103 However, some species that have been transplanted to southern latitudes have adapted quickly.104

B.C.s current biodiversity will increasingly persist in, or come to, the mountains or sanctuaryand survival. In mountainous terrain with steep climate gradients and extremely activehydrogeomorphological processes, species and ecosystems are highly sensitive to changes in climate anddisturbance regimes. Rapid change presents both challenges and opportunities in these uncompromising

The glaciers o Glacier

National Park have

retreated signifcantly in

recent decades.

Photo Amar Veluri


21/100



environments, which represent a provincial hallmark. In North America, a 100-m rise in elevation isroughly equivalent (ecologically) to travelling north 1 degree o latitude. Mountain and valley systemsprovide the best opportunities or biodiversity conservationbeyond the typical north-south and east-west opportunities or species migration, mountains also oer up-down altitudinal and contouringaround the mountain avenues or migration.

The elevational compression of biomes causes mountains to

become hot spots of biological diversity... This compression of lifezones explains why, on a 100 km grid scale, no landscape can beatthe biological richness of mountains. Nowhere else is it possible toprotect and conserve so much biological diversity within a relativelyrestricted region, than in mountains ...105

1.5.2 Natural Disturbances

Natural disturbances are undamental to ecosystem structure and unction.106 Recurrent disturbance and

recovery within ecosystems is an important mechanism or energy ow and nutrient cycling, and ormaintaining age, species, genetic, and structural diversity, all attributes o ecosystem health.107 But nowclimate change is pushing natural disturbance regimes beyond the historical range o natural variability.108,109Te increased requency and/or intensity o disturbances will aect the structure and unction o allecosystems. Interactions, eedbacks and synergies among natural disturbances, land uses, invasion o non-native species, and vector-borne diseases, among others, will exacerbate the eects o climate change. ManyB.C. ecosystems, such as lodgepole pine orests, boreal spruce orests, orest streams and riparian systemsdepend on periodic fre, insect outbreaks, debris slides, or oods and other disturbances or renewal andmaintenance o ecological integrity. As major agents o change in the coming decades, shiing disturbanceregimes and patterns could become as important as increasing temperature and changing levels oprecipitation.110

1) Insects and diseases

Insects and ungal disease will continue to play major roles in orest dynamics. Major agents o disturbanceand change include bark beetles, or example, mountain pine beetle, spruce beetle (Dendroctonus rufpennis),and Douglas-fr beetle (Dendroctonus pseudotsugae); oliage insects, or example, spruce budworm(Choristoneura occidentalis), western hemlock looper (Lambdina fscellaria lugubrosa), and orest tentcaterpillar (Malacosoma disstria); and ungal diseases (or example, Dothistroma needle blight, stem rusts,and root rots). Insects and diseases in general are very adaptable and could respond to environmental changeaster than their long-lived hosts;111 range expansions, contractions and shis, and an increase in the numberand variety o orest pests all can be anticipated as the climate warms.112,113 Pest outbreaks are expectedto increase, and to increasingly inuence the trajectories and outcomes o change, as orests disassemble,

reassemble, and ollow a variety o successional pathways.Willows will continue to decline as the willow stem borer spreads upward and northward and intensifes itsattacks. We still dont know to what extent the willows will recover. Many o them can resprout rom the stemor the base, but the new shoots appear to be o poorer quality than those produced aer normal mechanicaldamage or browsing. And the diseases that ollow the weevil into the stems can kill the shrub outright.Ecosystem consequences are also unknown but could be huge: think o the potential impacts on moose,beaver, snowshoe hare (and thereore lynx), grouse, songbirds (especially the neotropical migrants that seemto depend on willow thickets). Te damage could alter the ecological role o willows in wetlands, riparianhabitats, and upland orest and shrublands. It is also possible that other shrubssuch as alders (Alnus incana


22/100



tenuiolia, A. viridis) and scrub birch, which generally speaking are less valuable or wildlie, could increase atthe expense o willows.

2) Fire

We can expect more wildfres, larger areas burned, increased fre severity, and increased length o thefre season.114 While southern and central B.C. are expected to get warmer and drier in the summer andexperience more requent, severe, and extensive fres, northern B.C. is more likely to become wetter115 and

thus could experience a decrease in fre requency. Fire willprobably continue to be a rare event on the wet coast.

3) Mass movements

Permarost will continue to melt. Tis will result in morerequent earth slumps and landslides in terrain with permarost.Northern B.C. has scattered discontinuous permarost, mostoen ound in bogs and other peatlands, on north slopes, andmore generally at high elevations. Counterintuitively, such massmovements may increase local and regional biodiversity becausethey add site, soil and habitat diversity to the landscape, with

corresponding increases in species diversity.116

Tese impactswill be amplifed by existing disturbances. Logging and extensiveroad building have substantially increased the requency olandslides throughout the logged parts o the province. 117Soil disturbances caused by logging, mining, and natural gasexploration and development, and the associated resource roads,acilitate the spread o exotic invasive species.

4) Wind

Large-scale, catastrophic orest blowdown has, historically, beenrelatively rare in B.C., with return intervals o 300 to 500 plusyears.118,119 Windstorms are more requent on the coast than inthe interior, and the tree mortality due to wind events also variesregionally, ranging rom up to 80 percent in aected stands owet coastal orests to less than 15 percent in interior Ponderosapine orests.120 Disturbance regimes o wet coastal orests arecurrently dominated by fne-scale gap dynamics, with requentevents that aect only small numbers o trees.121,122Climatewarming will increase the intensity o atmospheric convectiveprocesses and thus the requency and intensity o windstorms.

Northern Vancouver Island, areas o the central and northern B.C. mainland coast, and parts o Haida Gwaiiare most susceptible to big blows. Frequency o catastrophic blowdown could increase to approximate winddisturbance regimes in parts o southeast Alaska. Large windthrow events there can have return intervals oless than 300 years, can dominate the disturbance regime, and are a major determinant o orest structure.123

Windstorms are oen accompanied by increased precipitation, a combination that can destabilize soils andincrease the requency o landslides.124

5) Invasive species

Te most signifcant overall trend in ecosystem structure could be increased dominance by opportunisticspecies that do well in changed environments or disturbed habitats.125 In other words, pioneering and earlysuccessional native species, and weedy invasive non-native species.126,127 Because invasive species lack naturalenemies in their new environment, they oen spread rapidly and can behave aggressively, or infltrate and

Mountain goats will increasingly encounter species o

lower elevations moving into traditional alpine habitats.

Photo Jason Puddioot


23/100



occupy both disturbed and undisturbed habitats. Tey oen change the structure and unction o ecosystemsby out-competing native species and by altering nutrient cycles, natural disturbance regimes, and trophicinteractions.128,129,130

Te 18 or so species o European earthworms131 invading B.C.s orests, which since Pleistocene glaciationhave retained a very ew native species o earthworms,132 show how introduced species can prooundlychange ecosystems.133 Tese earthworms have changed the way nutrients cycle, leading to a change in

community composition and reducing abundance o understory plants.134,135

Alien species are already a bigproblem in much o the province, being highly aggressive and adaptable, while new alien species continue tobe introduced.136,137,138

6) Disturbance interactions and uncertainty

Historical studies and models have improved our understanding o projected climate change impacts onindividual natural disturbance types. Interactions among disturbance types,and between natural and human-caused disturbances, are more di cult to orecast.139 Under rapid climate change, the dynamics and impactso compounded disturbances are likely to be unpredictable and could be unprecedented.

More requent and severe wind disturbance is likely to induce structural stress in trees, acilitating inectionby heart or butt rot ungi, and in turn increasing orest susceptibility to urther wind disturbance. 140 Similarly,

more requent drought can render trees more susceptible to disease outbreaks, which can temporarilyincrease the probability o fre. Research on impacts o mountain pine beetle outbreaks on fre suggests thatdead needles in the tree crowns result in a higher probability o fre crowning, aster rates o fre spread, andincreased fre intensity, as well as more long-range spottingbut only as long as the needles stay on the deadtrees. Once the dead needles have allen, dead stands o pine are no more likely to burn than live. 141 By thetime the dead pines all down, fre hazard will have decreased, but i fre does break out, surace fre would bemore intense and crowning in the remaining live tree canopy would be more probable.142

Human land-use activities oen have a synergistic interaction with natural disturbances.Decades o fresuppression coupled with climate warming have been implicated in the current huge outbreaks o mountainpine beetle.143 Te collective consequence o reduced mortality and shortened lie cycle o beetles, and theincreased area o climatically and demographically susceptible pine orests, set the system up or a beetleoutbreak and perhaps even or a undamental regime shi. Regime shis occur when a systems resilience isexceeded.144 Te conier-bark beetle/microbial symbiotic system includes key elements oen associated withregime shis: cross-scale interactions, positive eedbacks, multiple causalities, critical thresholds, sensitivityto external drivers.145 Other unprecedented regime shis are predicted in the coming decades.

Te combination o long-term fre suppression, wholesale planting o lodgepole pine, and moister summershas intensifed Dothistroma epidemics in northwestern B.C.146 Te current decline o whitebark pine inhigh-elevation orests provides an excellent and sobering example o the ripple eect o climate changeon disturbances. Whitebark pine is not regenerating very successully these days because o a) widespreadmortality o young trees due to the introduced white pine blister rust (Cronartium ribicola), b) beetle-causedmortality o cone-bearing trees, c) ewer fres that normally provide suitable sites or seedlings.147,148,149

Warmer temperatures at high elevations have enabled mountain pine beetle outbreaks to spread up into partso the whitebark pines range where they had not occurred beore.

1.5.3 Ecosystem Productivity

Several actors could contribute to increased ecosystem productivity. I moisture is adequate, plants growaster at warmer temperatures and with elevated levels o atmospheric CO

2150but only up to a point. For

example, tree species have temperature optima above which growth rates level o or decline.151,152,153,154Available nitrogen can become a limiting actor in a CO

2-enriched environment.155,156 Because plants exposed


24/100



to relatively high levels o CO2can partially close their stomata, thus reducing water loss and lengthening

their growing season,157 longer warmer summers with more CO2

could also result in more growth. Gains inaggregate yield o tree biomass could, however, be oset by nutrient limitations, maladaptation to changingenvironmental conditions,158 and losses due to other actors related to climate change, including increasedfre, insect and disease outbreaks, severe weather events, thaw-reeze damage, and increased moisture stressin some parts o the province.159,160,161

Projected eects o climate shis on productivity vary among regions o British Columbia, they also varyaccording to the modelling approach used. Wetter coastal ecosystems could beneft rom a longer growingseason. Drier ecosystems in the southern interior and along the south coast are likely to experience increaseddrought and decreasing productivity. Ecosystem productivity could increase in the north and at highelevations, where cold air and soil temperatures and short growing seasons currently limit plant growth. Insuch energy-limited environments, warmer temperatures combined with increased CO

2should result in

longer growing seasons, higher rates o photosynthesis, and increased primary production, decomposition,and rates o mineral cycling.162 However, unsuitable conditions or regeneration (or example, lack o mineralsoils in high mountains and northern muskeg), slow migration, and other actors such as nutrient limitationswill likely retard the emergence o productive orests in these regions.163

1.5.4 Freshwater Aquatic Ecosystems

Te implications o climate change or reshwater biodiversity are not certain, with strong variation expectedamong watershedsbut clearly lake and stream ecosystems and their dynamics will change.164,165 Habitatsand species o concern in aquatic systems are those susceptible to climate warming, such as:

cold-water habitats; cold-water species, or example, salmonid species; high altitude systems; small shallow lakes; small connecting streams.

Not surprisingly, fsh have received considerable attention to date.166,167

Climate change will alter thedistributions o reshwater fsh in B.C. through changes in water temperatures, precipitation, streamow, andintroduction/invasion o non-native species.168 Warming rivers, lakes and the ocean will continue to impactpopulations o salmon and other fsh species by inuencing the timing o migrations, the availability o ood,and the habitat suitability o river systems.169 Changes in runo and other streamow characteristics areanticipated and could aect spawning habitat, either through erosion and sedimentation during peak owsand oods, or through exposure during low ows.170 Fewer salmon returning to B.C.s rivers will reduce theood resource or consumers such as bears and bald eagles, resulting in ecosystem-level impacts on nutrientcycles and orest ood webs.171

More requent drought and extended summer low-ow periods are expected in some rainall-drivensystems, urther increasing water temperature, modiying ecosystem structure and unction and avouring

warm-water species. Te timing and intensity o reshet oods will change in streams ed by melting snowor glaciers. Some such systems could eventually become rainall-driven, rather than glacier melt or snowalldependent, a hydrological transormation with large ecological impacts.

Lakes and ponds are also very sensitive to temperature changes. Many lakes have a characteristic cycle othermal stratifcation that sets up in the summer and turns over in the all, mixing nutrients and oxygen inthe water column. Tis undamental dynamic will be altered as water temperatures increase and as winter icediminishes.172 Paleoecological studies indicate that the composition o lake biota is also a unction o watertemperature. We can expect increasing compositional changes in the coming decades, as well as trophicmismatches and the resultant changes in system unction.173 Moreover, some small lakes could become


25/100



smaller and shallower, or even dry up as the climate warms, resulting in changes to shoreline and aquaticcommunities.174

Aquatic conditions depend on past glacial history and uture climates. Fish species are still undergoing apostglacial expansion into northern B.C. and the Yukon. Landorms and the relationship between landand water created by the glaciers determine current fsh habitat. Tere are a variety o lakes with dierentcharacteristics, including shallow depositional lakes. With climate change, such shallow lakes will warm to

the point that certain fsh species no longer will be able to survive in them.Beyond the changes in the timing and amount o the spring melt and peak ows, warming is also expectedto accelerate the water cycle (increasing rates at which water enters the atmosphere and rains or snows downagain). Te eects o this on hydrology, fsh and invertebrate populations remain to be seen. Freshwatersystems are constrained by topography; reshwater aquatic species have limited migration options becausetheir habitat is within the lake/stream system.

Changes in water temperature could aect fsh populations dramatically. For example, there is evidence(noted above) that suggests salmon may soon be unable to migrate through the Fraser River due to overlywarm waters.175 On the other hand, salmon returns to the Mackenzie River could increase, allowing thefsh to reach the upper Liard River system in B.C. Pacifc salmon are known to occur to a limited degree in

Canadian Arctic waters, with reports o pink, chum, sockeye, and coho in decreasing order o requency. Stray salmon continue to turn up in the catches rom domestic and subsistence fsheries in the Arctic; theGwichin Renewable Resource Board (Inuvik) confrms that salmon have been caught in the Mackenzie Riverdelta, as well as upriver near Arctic Red River, Norman Wells, and in the Peel River. 176

Glacial recession is ongoing and continues to create new habitats. Receiving waters have high turbidity(cloudiness due to suspended sediments) and lower productivity. Over time, the yield o water rom non-glacial rivers could increase or decrease, depending on precipitation trends, whereas the yield rom glacialrivers is already increasing and there is an ongoing contraction o spawning habitat or some species. Someother rivers become more suitable or spawning as water levels drop. Larger streams will sustain spawninghabitat over such change. Small creeks are most at risk rom alling water levels. Eventually even glacial riverswill have reduced ows as the ice melts away.177

1.5.5 Summary of Future Ecosystem Responses

Te predicted changes in climate in this century are expected to result in signifcant ecological change,in addition to what has been witnessed to date. Although uncertainties abound, two principles guide theinterpretation o these changes. First, ecosystems do not migratespecies do. Second, most species cannotdisperse (move) quickly enough to keep pace with the projected changes. Tese two actors together willaect how uture ecosystems take shape as plant and animal species shi their ranges largely independentlyand at dierent rates.

Over time, projected changes will result, at least in southern B.C., in trends such as increases in weedy,

drought-tolerant, and alkali-tolerant species, and decreases in moisture-loving and acid-tolerant species.Elements o southern orests and grasslands will expand northward but these grasslands will probablybe mongrel ecosystems with high proportions o invasive species. Forests will move upslope into alpinehabitats. Decreasing snowpacks, shrinking glaciers, melting permarost, warming streams and oceans,increasing requency and intensity o disturbancesincluding pest outbreaks, wildfres, storms, oods,drought and erosionwill negatively aect the structure and unction o all present-day ecosystems. In otherwords, they will undergo ecological upheaval and some will unravel.

As agents o change, shiing disturbance regimes and patterns could become as important as increasingtemperatures and changing levels o precipitation. Te increasingly acute threat to nature as we know it is not


26/100



climate change acting in isolation, but rather the combination o climate change and intensiying changesmade to natural landscapes and systems by humans. Responses o B.C. ecosystems to these changes will becomplex and are di cult to predict because they reect the combined and synergistic eects o changingclimate, natural disturbances, land and resource uses, and the spread o invasive species.

Some o these changes may have short-term benefts or people, or example, a longer growing season, butmost will adversely aect the provinces natural capital and the goods and services that British Columbiansderive rom nature. Climate-related impacts are already changing the way ecosystems work or us. Te abilityo ecosystems to produce oxygen, puriy water, make soil or adjust to disturbances will be challenged innew and unpredictable ways. As well as natural disturbances, increased human disturbances, diseases, andinvasive species will exacerbate the eects o climate change.

What we do on land matters or the oceans as well. Oceans are a large sink or CO2, but as emissions o CO

2

go up, oceans are absorbing more CO2, orming more carbonic acid, and acidiying at an escalating rate. Tus

as calcium carbonate becomes less available, the oceans are becoming less hospitable or many organismsincluding shellfshthat store carbon in their bodies, shells, and skeletons, and on which we directly andindirectly depend or ood and our economy.

1.6 Future Species Responses

Species conronting rapid environmental change will either go extinct or survive. Te extinction riskincreases i suitable habitat conditions either disappear entirely178 or, as is more likely, i habitats shi morerapidly than resident species can migrate.179 Species have three survival options: acclimatize to the newconditions, evolve new coping mechanisms, or migrate to suitable habitats elsewhere.180 For many organisms,evolution probably will not occur rapidly enough to keep up with the current and anticipated rapid pace oclimate change,181 especially i habitats have already been degraded by various land uses.

The ocean is a crucial carbon sink that is

now becoming increasingly acidifed as it

absorbs more and more CO2 This reduces the

availability o calcium, which shellfsh such as

this dungeness crab need or shell-making.

Photo (let)Jefrey Waibel, (above) Hanson Quan


27/100



1.6.1 Species of Most Concern

Te conservation status o only 3,841 species native to the province has been assessed, a small ractiono the more than 50,000 species that exist here.182 Te relatively well-known species include vascular andnon-vascular plants, vertebrates (mammals, birds, amphibians, reptiles and reshwater fsh), and selectedinvertebrates (non-marine molluscs, butteries/skippers, and dragonies). For these taxonomic groups,analyses o global and provincial conservation status (imperilled, vulnerable, apparently secure, and so on),

trends, and patterns are available.183More useully, these species have also been assessed or the proportion o their global range that occurs inB.C. Tus we know that about 100 o the 3,841 species assessed have all or the majority (that is, greater than50 percent) o their global range, area or population within our province.184 Tese 100 or so are the species orwhich British Columbia is known to have the greatest stewardship responsibility. 185 Whether a species is a)endemic and secure, or example, Newcombes butterweed; b) endemic and at risk, or example, VancouverIsland marmot and several white sturgeon populations); c) widespread but vulnerable or example, bull trout(Salvelinus conuentus) or; d) widespread and secure, or example, mountain goat and sooty grouse, or mosto these species the most avourable portion o their range, and the area best placed or their conservation,is currently in B.C. In a ew instances, the best habitats o highly vulnerable species are on private or FirstNations reserve land, or under regional and municipal jurisdiction.

Many o the species o cially listed as at risk in B.C. are either northern boreal or arctic-alpine taxa at thesouthern limit o their range, or they are southern taxa, whose northern range limits extend to southern partso the province. Te northern species are unlikely to persist in outpost localities as climate continues to warmand to push their climatic envelopes northward and upward. I populations o northern species peripheral inB.C. are widespread and secure in the Yukon, Northwest erritories and/or Alaska, B.C. conservation eortsneed not be preoccupied with them. In contrast, species with southern a nities that reach their northernrange limit in B.C. could spread arther north and become more requent in a warmer, uture B.C.

When one analyses the distributional patterns o species in the province, one quickly notices that bothspecies richness and the numbers o species at risk are highest in southern B.C. Te ecological impacts ourbanization and agriculture are also most pronounced in low-elevation areas throughout southern BritishColumbia. Te Coastal Douglas-fr (CDF), Bunchgrass (BG) and Ponderosa Pine (PP) zones, all o whichhave a restricted distribution in B.C., have already been particularly aected.

Forty-fve percent o the CDF has been converted to urban, rural residential and agricultural use. Oparticular concern in the CDF is the devastating loss (nearly 90 percent) o Garry oak woodlands,aesthetically pleasing ecosystems with high species richness and many at-risk species.186 Te alteration orconversion o wetlands is also a serious concern. Te remaining, mostly secondary orests and woodlands othe CDF are being infltrated by non-native invasive plants, including spurge-laurel, English ivy, Himalayanblackberry, and numerous grasses, eliminating or reducing native species and changing ecosystem processes.

Te BG and PP zones in B.C. are small, but they support much biodiversity, in part due to the juxtapositiono grassland, shrub-steppe, riparian, and orest habitats. Te BG zone also represents an insinuation o

intermontane steppe o the Columbia Basin into the northern orests. Both southern and northern speciesrequent the zone. However, nearly 20 percent o the species in the BG and PP zones 187 are at risk because ohabitat loss, overgrazing, and the invasion o non-native plants particularly knapweed (Centaurea spp.) andcheatgrass (Bromus tectorum). Similar to the CDF zone, urbanization has converted 18 percent o the BGzone and 16 percent o the PP zoneincluding most o the endangered antelope brush/needle-and-threadecosystem o the southern Okanagan Valleyto urban, rural residential and agricultural use.188

Another way o addressing this issue is to look at the distributional patterns o species with a majority o theirrange in B.C., the stewardship responsibility group. Te resulting pattern is similar, with increased profle orHaida Gwaii and Vancouver Island and the north, and more ocused emphasis on the Lower Mainland and


28/100



the Southern Interior. Either way, the our lower elevation biogeoclimatic zones (CDF, BG, PP, and IDF) osouthern B.C. host the most species diversity and concentrations o species at risk. Tese areas also have thehighest densities o human population and have lost the most habitat to urbanization, rural residential use,transportation corridors, and agriculture. Te same our zones plus parts o the Coastal Western Hemlockzone, particularly Vancouver Island and Haida Gwaii (both heavily logged), are most signifcant with respectto the stewardship species. Much habitat has been lost or degraded already and the remnants are particularlyvulnerable to human impacts in addition to climate change.

1.6.2 Specialised Species

Species o unusual specialised habitats (or example, archaebacteri and molluscs in hot springs, erns(or example, Polystichum kruckebergii, P. scopulinum) restricted to ultrabasic bedrock, and subterraneancave species) are more likely to persistas long as their special habitats continue to exist. In any case, thespecial enduring eatures (hot springs, serpentine talus, and karst terrain) will probably continue to supportregionally rare or unusual species and ecosystems indefnitely. Te Grand Canyon o the Stikine, theultrabasic bedrock o the Shulaps Range, hot springs, coastal dunes, karst on Vancouver Island and HaidaGwaii, and spray zones o wateralls will continue to support some sort o regionally unusual biota almostregardless o how much the climate changes. It probably makes conservation sense to ocus on the specialenduring eatures as much as on their unusual contemporary species.

1.6.3 Keystone Species

Some species are more important ecologically than others, regardless o their commonness or rarity. Tisincludes animal species at higher trophic levelsabundant herbivores and top carnivores, responsible ortop-down regulation o both terrestrial and aquatic ecosystems. Te interplay and eedback among highertrophic levels (consumers: herbivores and predators) can have a large eect on plant species composition andecosystem productivity.189 Examples are moose and gray wol in boreal orest; black-tailed deer (Odocoileushemionus columbianus) and cougar in coastal orests; snowshoe hare (Lepus americanus) and Canada lynx(Lynx canadensis) in northern orests; overabundant Sitka black-tailed deer (Odocoileus hemionus sitkensis)

introduced on Haida Gwaii and Rocky Mountain elk (numbers increased as a result o burning practices) inthe northern Rockies.

Keystone species are those that exert a disproportionately large inuence on ecosystems, much largerthan would be expected rom their abundance. Somelike beaverhave been characterized as ecosystemengineers,190 creating habitat or niche space or a host o other species. Keystone species can also includestrongly interacting species,191 including top predators192 like gray wol, cougar, lake trout (Salvelinusnamaycush),193 and alcons, as well as small mammals that orm the prey base, such as voles and snowshoehares.194,

Te reintroduction o gray wolves into Yellowstone National Park in Wyoming has demonstrated both thekeystone role that top predators can perorm and the importance o that role in the ace o climate change.

Wolves determine the availability o carrion and buer the eects o climate change or the scavengers relianton carrion. Without wolves prolonging the late winter carrion, many scavengers would go hungry as thewinters warm and shorten.195

I climate change has a signifcant impact on any o these sorts o species, most o which are not consideredconventionally to be at risk, the cascading consequences or other species and or ecosystems could behuge.196,197 Te overall eect on biodiversity and ecosystem services will be much greater than that rom theextirpation o rare listed species.


29/100



1.6.4 Significance of Trees as Foundation Species

rees also provide a hugely important role and have been described as oundation species.198 Impacts

on B.C.s common and abundant tree species, which so dominate the provinces orests, will also have

consequences or virtually every orest organismrom caribou to birds and beetl

new climate for conservation

Documents