Download - Garden ecology 2015
© Project SOUND
Out of the Wilds and Into Your Garden
Gardening with California Native Plants in Western L.A. County Project SOUND – 2015 (our 11th year)
© Project SOUND
how ecology can help you garden
better and provide habitat
C.M. Vadheim and T. Drake
CSUDH & Madrona Marsh Preserve
Madrona Marsh Preserve
February 7 & 12, 2015
Gardening like an Ecologist:
What is ‘sustainable living’
Thriving lives & livelihoods
Sustainable food security
Secure sustainable water
Universal clean energy
Healthy & productive ecosystems
Governance for sustainable societies
© Project SOUND
http://nancysteele.files.wordpress.com/2013/03/image0011.jpg
Living within our means to provide:
How does sustainable gardening fit in?
Provides thriving lives for us and those whose work supports the garden – [act/use locally]
Provides healthy food for us and others
Uses water wisely; protects & augments our groundwater
Uses practices that promote wise use of clean energy
Creates healthy and productive ecosystems in our gardens and neighborhoods – diverse habitats
Leads to governance for sustainability
© Project SOUND
Sustainable gardening: based on the
combination of art and science
© Project SOUND One of the most relevant scientific disciplines is ecology
© Project SOUND
http://nancysteele.files.wordpress.com/2013/03/image0011.jpg http://scienceunraveled.com/DDT+Pesticide+Effects+on+Ecology
What is ecology? The scientific analysis and study of interactions among organisms and their environment
The study of how living things interact with their environment over space and time
Garden ecology: the study of how living and non-living things interact and change over time in a garden
© Project SOUND
http://scienceunraveled.com/DDT+Pesticide+Effects+on+Ecology
One of the most obvious observations:
spatial patterns
Organisms [plants] have a spatial distribution
Usually it’s neither uniform or random
?? What explains the spatial pattern
Spatial ecology Study of spatial patterns and their
relationship to ecological factors
Two sub-disciplines Landscape ecology
Meta-population ecology
© Project SOUND
http://en.wikipedia.org/wiki/Range_(biology)#mediav
iewer/File:Population_distribution.svg
uniform
random
clumped
The sub-discipline of Biogeography also
studies spatial distributions
Population distributions: often clumped
Can you think of any plants that have a uniform distribution?
What might a uniform pattern indicate?
© Project SOUND
http://en.wikipedia.org/wiki/Range_(biol
ogy)#mediaviewer/File:Population_distri
bution.svg
random
clumped
uniform
• Plants in a garden
• Creosote bush (dry conditions)
• Purple sage - Salvia leucophylla
http://www.biosbcc.net/b100plant/htm/soft.htm
© Project SOUND
Purple Sage (and it’s offspring)
Flowers: usually purple (lavender to pink-purple) in ball-like whorls
Leaves:
Relatively small (< 1 inch long)
White to gray-green “flame-shaped” – often with
a fold Look somewhat “pebbly”
Plants: usually large, mounded
Generally long-lived in nature
Brother Alfred Brousseau. ©St. Mary's College of
California
http://www.fw.vt.edu/DENDRO/d
endrology/Syllabus2/factsheet.cf
m?ID=775
© Project SOUND
Purple Sage: clues from nature
Large size in moister sites
Probably was browsed historically
Lots of inherent genetic variability
Drought-deciduous; likes some summer drought
Coastal forms bloom earlier than inland forms (?due to our milder climate)
http://www.santabarbarahikes.com/flowers/index.php?action=show_i
tem&id=170&search=
But why the interesting spatial distribution?
Salvia leucophylla thickets (some sites)
Surrounded by zones of bare soil (“bare zone“, 2-4 ft in width),
Ringed by areas of inhibited grassland (“zone of inhibition“) and finally undisturbed grassland at a distance of 10-20 ft.
Purple sage plays dirty
Produces monoterpenes, especially 1,8-cineole, camphor & beta-pinene
Inhibit cell growth, particularly the root stem cells (meristem cells), of young plants
© Project SOUND
The “Salvia phenomenon“
is one of the most famous
examples of allelopathic
interaction between higher
plants
Camphor
A simple observation launched an interesting
biochemical inquiry
© Project SOUND
Conclusion: sometimes spatial patterning is due to
competition between members of same/competing species
What does that mean for my garden?
Purple sage will compete fiercely when conditions are bad
Over time, the area around a Purple sage may eveolve
© Project SOUND
http://nathistoc.bio.uci.edu/plants
/Lamiaceae/Salvia%20leucophyl
la.htm
Common types of spatial patterns seen in
plants in natural places
Gradients (trends) steady directional change in numbers over a specific distance
Patches (clumps) a relatively uniform and homogenous area separated by gaps
Noise (random fluctuations) variation not able to be explained by a model
© Project SOUND
Annual wildflowers (and other plants that re-
seed well) provide a unique opportunity to
observe patterns in our own gardens
© Project SOUND
© Project SOUND
* Godetia/Farewell-to-spring – Clarkia amoena
http://www.yerbabuenanursery.com/images/garden_weekly/amoena_cu1_wk12_big.jpg
© Project SOUND
* Godetia – Clarkia amoena
http://ucjeps.berkeley.edu/cgi-
bin/get_JM_treatment.pl?5263,5341,5343
CA and OR coast north of San Francisco Bay
Generally open, drying places, < 1500 ft.
Found in coastal scrub, prairies and dry open coastal slopes & bluffs
A staple of cottage gardens world-wide since the 1800’s
Charles Webber © California Academy of Sciences
© Project SOUND
Godeta is similar to our local Clarkias
Size: 1-3 ft tall
1-2 ft wide
Growth form: Annual wildflower
Upright, branched form
Foliage: Leaves simple
Typically blue-green to gray-green – may be tinged with red or magenta
© 2002 George Jackson
© Project SOUND
Godetias: typical
annual wildflowers Soils:
Texture: any
pH: any local
Light: Full sun to light shade
Water: Winter: plenty of water
when growing
Summer: water until flowering slows, then taper off to none
Fertilizer: whatever – not particular
Other: can serial sow seeds every 2 weeks to get longer bloom (into summer with water)
© 2005 Doreen L. Smith
So what explains the ‘wildflowers in a
crack’ phenomenon
Abiotic factors: Increased water
Soils stay moist longer
Soils warm up quicker
Seeds more likely to stay on/near surface?
Micro-site changes from leaching?
Increased nutrients?
Biotic factors Decreased competition for light
from other annual wildflowers?
© Project SOUND
Factors related to germination/
seedling survival
There may also be factor associated with
the seed & its dispersal
Abiotic factors: Seed drop patterns (plants
hang out over the walkway)
Physical barriers/rough surfaces result in increased seed deposition
Wind patterns
Biotic factors Decreased predation of seeds
that are located on the peripheries or in areas where detection is difficult (primarily by birds)
© Project SOUND
http://upload.wikimedia.org/wikipedia/commons/a/a9/White-
crowned_Sparrow_HMB_RWD4.jpg
Observations can lead to testable
alternate hypotheses
Clarkia amoena grows densely in nature; probably not due to competition for sunlight
© Project SOUND
Could easily test other
hypotheses in garden/
greenhouse experiments
You don’t have to know the mechanism(s)
to use the insights in your garden
Placement of wildflowers Along edges of paths, beds
To fill in bare areas
Plants will re-seed to these areas if happy for many years
Make existing habitat more suitable: Leave some areas without thick
organic mulch; let mulch degrade
Use gravel mulch (or none) in places where you want to encourage wildflowers
Know that wildflower removal is a part of spring gardening Hand weeding
Vinegar spray (decreases pH) © Project SOUND
Over short time periods, annual plants provide a
model that’s useful even at the garden level
© Project SOUND
The patterns are most obvious when you
observe a developing (young) garden
© Project SOUND
Cobwebby Thistle – Cirsium occidentale
http://www.ubcbotanicalgarden.org/potd/2006/01/cirsium_occidentale_var_occidentale.php
© Project SOUND
Cobwebby thistles are nice thistles
Size: 1-4 ft tall
1-3 ft wide
Growth form: Biennial or short-lived perennial
Basal rosette of leaves in first year; flowers second year
Fast-growing; not invasive, but does re-seed
Tends to ‘move around the garden’
Foliage: Foliage gray-green, very wooly
Spiny, coarsely toothed leaves – very showy
http://plants.montara.com/ListPages/FamPages/Astera3.html#cirocc
Like all sciences, ecology attempts to
describe and understand patterns
In a given setting/time, how are plants distributed (patchiness; gradients) - description
What factors explain that distribution? Non-living (abiotic) factors
[resources; toxicities]
Plants of the same species
Other plant species
Other living things
Prediction
© Project SOUND
http://www.fairchildgarden.org/Portals/0/images/CTPC/Javier
s_Pictures/Feeley-Ecology-Cover-Small-small.jpg
Plant distribution is strongly affected by
abiotic factors
Three main types of abiotic factors important for plants:
Climatic factors: sunlight, atmosphere (incl. pollutants) , humidity/water, temperature, and salinity;
Edaphic (soil) factors: coarseness of soil, local geology, soil pH, aeration, etc.
Social factors: including land use.
© Project SOUND
© Project SOUND
Cobwebby thistle has a few ‘gardening’ requirements
(note that we always discuss the abiotic factors)
Soils:
Texture: must be well-drained; sandy/rocky soils best
pH: any
Light: full sun to light shade
Water:
Summer: none to occasional; would do well with native annuals
Fertilizer: none – likes poor soils
Clearly there’s more going on than just
abiotic factors limiting establishment
© Project SOUND
We need to consider other factors,
including the relationships of seedlings to
their parents - dispersal
http://en.wikipedia.org/wiki/Biological_dispersal#mediaviewer/File:Dispersal_diagram.jpeg
Population Ecology: the study of groups
of the same species
Demography: patterns of populations in time/space & their determinants
Dispersion pattern
Population density
Population dynamics Life strategies (that influence
population dynamics)
Migration
Mortality/natality
Survivorship curve
Carrying capacity
© Project SOUND
Biological dispersal – in general
Definition: refers to both:
the movement of individuals from their birth site to their breeding site
the movement from one breeding site to another ('breeding dispersal').
Important consequences for gene flow (the movement of ‘genes’ from one population to another) – more on this in May
© Project SOUND
http://en.wikipedia.org/wiki/Biological_dispersal#mediaviewer/File:Dispersal_di
agram.jpeg
Plants reproduce both
sexually & asexually
Sexually – by seeds
Vegetatively (natural clones) Offsets [Agave]
Plantlets [strawberry]
Bulblets [bulbs & corms]
Layering (rooting stems)
Other (broken pieces have the ability to root) [Willows]
© Project SOUND
Propagule dispersal: The key to
understanding plant ecology
Seed dispersal: the movement or transport of seeds away from the parent plant.
Plants have limited mobility; rely on a variety of dispersal vectors to transport propagules, including both abiotic and biotic vectors.
© Project SOUND
Animals tend to move away from densely
populated areas to areas with less
competition for resources
Density-dependent dispersal
© Project SOUND
Plants are characterized by density-
independent dispersal
Propagules (seeds; vegetative propagules) are distributed passively, mostly by vectors:
Biotic vectors Animals that allow seeds to ‘hitch-hike’,
Animals that eat fruits
Humans that purposefully move them
Abiotic vectors Wind
Water
Gravity
Other (ballistic) Plants that ‘fling their seeds’ [Lupines;
CA poppy]
© Project SOUND
© Project SOUND
Flowers make a bold
statement
Blooms: usually April-July along coast
Bloom period: 3-4 wks
Flowers: Super-showy thistle flowers
Pollinated by bees, flies, butterflies (American & Painted Ladies)
Seeds: Will self-sow; rarely weedy
Vegetative Reproduction: no – not invasive
G.A. Cooper @ USDA-NRCS PLANTS Database
http://plants.montara.com/ListPages/FamPages/Astera3.html#cirocc
Propagule dispersal
also involves
relationships
Implication: strong inter-dependence between dispersion success and the dispersing vectors
This is true whether the vector is abiotic or biotic
Water-dispersed seeds require running water – consequences of drought
Animal dispersed seeds require adequate animal/bird dispersers
© Project SOUND http://maggiesscienceconnection.weebly.com/seed-dispersal.html
Clues to dispersal mode: patterns &
observation
© Project SOUND
what is the dispersal mechanism?
what dispersal pattern?
As always, reality is a
little more complex
© Project SOUND
Seeds can be dispersed away from
the parent plant individually or
collectively, as well as dispersed in
both space and time.
Another pattern – observed several years after an
El niño year at Rancho Santa Ana Botanic Garden
© Project SOUND
Propagule dispersal: the key to
understanding plant ecology
The patterns of seed dispersal are determined in large part by the dispersal mechanism
Important implications for:
the demographic and genetic structure of plant populations
migration patterns
species interactions.
© Project SOUND
The distribution we see can reflect a
complex set of circumstances
© Project SOUND
http://people.mbi.ohio-state.edu/beckman.57/Research/img/droppedimage.png
Particularly so for plants that live longer than a season
Golden currant distribution: what do these
patterns mean?
Often in areas with seasonal water:
River banks (upper)
Seasonal streams
Ravines/arroyos
On flood plains
In CA, also found: On cliffs and bluffs
On sandy hillsides
On mountain slopes in mountain scrub - < 8000 ft
Studying seed dispersal is not all that
easy – particularly in the wild
Most studies just map the dispersal of offspring around a single or group of parent plants
Better to study the dispersal of seeds themselves - often difficult Seed rain studies (for wind
distributed seeds)
Studies of soil/duff seed bank
Modern technology is adding interesting insights Labeled seeds (radio-label or genetic)
GPS monitoring of bird/animal seed dispersers
© Project SOUND
http://theoffday.com/images/2014/12/page/87/
As expected, seedling density for
many plants is highest near the
seed source
Recent studies provide tantalizing
clues about the complexity of seed
dispersal Wind patterns are revealed
for Mahogany seedlings
As expected, highest density is nearest the ‘parent’ tree
More distant seed distribution primarily reflects the prevailing wind patterns at the time seeds disperse
Other trees have little effect – all are deciduous at dispersal time
© Project SOUND http://www.swietking.org/description.html
http://www.rockwoodventures.co
m/images/p5_Mahogany_Seeds
.jpg
Hints for your garden
Really get to know the physical characteristics & patterns in your garden: soils; light; wind; water flow
Look at the distribution of weedy plants that grow from small seeds (annual weeds; grasses). What clues do they provide about neighborhood sources?
Tip for the thrifty and time-efficient gardener/restorationist : when planting annual wildflowers, take into account prevailing winds
© Project SOUND
Bird dispersal – tropical fruit (nutmeg)
Toucans (dispersal agent) GPS tracked to see where they went; birds were studied to see how long seeds were retained
Modeled likely dispersal patterns: Most seeds were locally deposited
Dispersal was furthest for seeds ingested in the morning
Some seeds were predicted to be deposited at some distance from the parent tree
© Project SOUND
http://smithsonianscience.org/wordpress/wp-
content/uploads/2011/07/kays_etal_2011_BLD_Toucans-2.bmp
Dispersal modeling using
biologic and ecologic field
data
Look for examples of bird-seeded plants
in your garden
Your neighbor’s macadamia or other nut trees popping up in unexpected places
Oak seedlings appearing out of nowhere
Fruit tree seedlings where squirrels, raccoons or possums eat
Any other examples?
© Project SOUND
Many plants have multiple modes of seed
dispersal Seeds of most plants are dispersed
by a combination of factors
Primary & secondary dispersion
Animal dispersion can result in either random or clumped patterns depending on animal behavior & biology:
Caching [jays; squirrels; ants]
Eating behaviors [where they eat]
Defecation patterns [latrines]
Foraging patterns
Just for fun: track the dispersal of a newly-introduced ‘seeder plant’ in your garden. What vectors play a role?
© Project SOUND http://en.wikipedia.org/wiki/Mourning_dove
Dispersion costs resources (energy)
Most dispersal mechanisms require some sort of specialized ‘apparatus’ – takes energy away from other needs
Reproduction is important – but why spend precious resources on dispersion?
© Project SOUND
Dispersal costs resources - why disperse?
Costs: energy, risk, time and opportunity
Benefits for the individual: Locating new resources [water; nutrients]
Escaping unfavorable conditions Density-dependent predators & diseases
Environmental modifications by species [toxic soil chemicals; shade]
Avoiding competing with siblings/ parents
Benefits for the species: Avoiding breeding with closely related
individuals which could lead to inbreeding depression
Increasing geographic range - less risky for species survival; possibly more resources
© Project SOUND
The short answer:
plants disperse
because they have to
Dispersal is a key ecological process, that enables local populations to form spatially extended systems called metapopulations
Understanding the dynamics of metasystems may be key for species conservation – now and in the future
More on that in May
© Project SOUND
We’re beginning to appreciate that the
distribution we see (even for short-lived
plants) is often complex
© Project SOUND
http://people.mbi.ohio-state.edu/beckman.57/Research/img/droppedimage.png
That’s because lots of processes are going on simultaneously
Seedling survival: long road from seed to
seedling, adult plant
Patterns seen in mature plants
may not be a good indicator of seedling dispersal
Survival depends on both density-dependent & density independent factors
Density-dependent Biotic factors: competition;
density-dependent predation, disease
Density-independent Abiotic factors: temperature; soil
moisture
© Project SOUND
Dispersal and your
garden
Importance of the ‘founders’ When planting from seed, more
is better (in terms of genetic varviability)
Use locally obtained seed
Importance of seedlings Increase genetic variability
Become increasingly adapted to your local garden conditions – selection in action
Importance of ‘naturalizing’ Plants find their own place
Increase population size
© Project SOUND
Implications for the field of ecology
Need bigger, longer studies or dispersion – most previous have been too limited
Models based on (and tested against) field observations
Models may allow plant ecologists to model the effects of individual factors when other factors are kept constant
© Project SOUND
Predictions always need to be
tested in the field
One topic that has received considerable
recent attention is the idea of ranges
Range: the geographic area where a species occurs
Actual
Potential
Historic
© Project SOUND
Range map for Achillea millefolia (Yarrow) complex
http://linnaeus.nrm.se/flora/di/astera/achil/achimilv.jpg
Western fence lizard (Sceloporus occidentalis)
© Project SOUND
http://www.californiaherps.com/lizards/pages/s.o.long
ipes.html
Local ssp. longipes
Range: western N. America from WA to Baja CA
Why might this species have such an extensive range?
© Project SOUND
Ashy-leaf Buckwheat – Eriogonum cinereum
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?Eriogonum+cinereum
CA coastal endemic:
s Central Coast, w South Coast, from Santa Barbara County south to San Pedro
n Channel Islands (Santa Rosa Island)
On dunes and bluffs in coastal strand and
On slopes and ridges further inland in coastal sage scrub at elevations < 500 m.
Ranges can be
helpful to gardeners
Cosmopolitan species: species with large geographical ranges Sites where it grows usually share
a very common characteristic (often related to water availability)
Supply that factor, cosmopolitan species are easy to grow
Endemic species: geographically restricted species (must be specified; relative term)
May have many very specific needs
May be most successful locally
© Project SOUND
http://linnaeus.nrm.se/flora/di/astera/achil/achimilv.jpg
© Project SOUND
California Buckwheat - Eriogonum fasciculatum
Southwestern U.S.
to Utah, Arizona, nw Mexico s Sierra Nevada, Central
Western California, Southwestern California, East of Sierra Nevada, Desert
Common. Dry slopes, washes, canyons in scrub < 2300 m.
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5936,5994,6045
var. fasciculatum
var. foliolosum
Why are plant species limited in their
ranges?
Interpreting the possible causes of a species’ range: requires consideration of three types of factors:
Dispersal
Niches
Spatial variation in environments
© Project SOUND
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5936,5994,6045
Ashyleaf buckwheat
California buckwheat
© Project SOUND
Buckwheat seeds Each flower houses a single ovary which forms a hard one-seeded fruit called an achene (a sunflower seed is another achene).
Buckwheat achenes are 1–3 mm long and typically fall from the plant attached to the dried corolla when mature.
The achene detaches (dehisces) from the flower when ripe.
Most local buckwheat seeds can be planted with no pre-treatment
Most buckwheat seeds germinate best when planted fresh – within 1 year of formation
http://www.cbgscience.org/great_basin/seed_bio_eriogonum.htm
corolla
© Project SOUND
Buckwheat seeds
disperse via many
pathways
Eriogonum seeds are dispersed by wind, rain, streams, and animals.
Due to their high oil content, the seeds float and are readily moved by flowing water and sheeting of water during heavy rains.
Birds & small animals are also likely dispersal vectors, particularly for annual species of Eriogonum. The oil-rich seeds are a valuable food source for many animals.
Many species of Eriogonum actively engage ants in their seed dispersal.
Some Eriogonum species even have specialized structures on the seed which store oil and attract ants.
Ants will often carry seeds of Eriogonum underground where they are provided a safe site for germination
Both species likely use
multiple dispersal vectors
Why are plant species limited in their
ranges?
Interpreting the causes of species’ range limits requires consideration of three types of factors:
Dispersal
Niches
Spatial variation in environments
© Project SOUND
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5936,5994,6045
The concept of the ecological niche
Many definitions – concept has evolved over time
Definition: Place or function of an organism within its ecosystem
Definition: that set of environmental factors (both abiotic and biotic) which permits populations to persist.
A niche is a very specific segment of ecospace occupied by a single species
© Project SOUND http://science.kennesaw.edu/~jdirnber/ecology/Lecture/LecComEcol/LecComEcolCom
p/LecCommEcolComp.html
Hutchinsonian
niche
Hutchinsonian niche: an n-dimensional hypervolume of conditions and resources [in reality, almost never completely known/defined]
Fundamental niche: what an organism's niche would be in the absence of competition from other species.
Realized niche: The niche that a species actually inhabits, taking into account interspecific competition
© Project SOUND http://science.kennesaw.edu/~jdirnber/ecology/Lecture/LecComEcol/LecComEcolCom
p/LecCommEcolComp.html
Limits to a plant’s range: several types of
factors
Abiotic factors [physical/inanimate factors]
Biotic factors [living things]
Anthropogenic factors [caused by humans]
Genetic factors [limit spread of a population]
Time
Combinations of the above
© Project SOUND
http://www.pacificbulbsociety.org/pbswiki/index.php/DomedAlliums
Abiotic factors: very important for plant range
Temperature
‘Growing’ season – e.g. time available for reproduction
Water
Soil factors Nutrients
pH
Structure [sandy; clay; rocky]
Geographic barriers [deserts; oceans; mountains]
© Project SOUND
Interestingly, there are very few ecological studies testing
the tolerances/limits for specific plant species
Comparison of possible niche requirements
Ashyleaf buckwheat
Blooms: Apr-Oct [Aug-Oct MNBY]
Soils: Texture: sandy to clay; well-
drained
pH: any local
Light: full sun near coast; part-sun further inland
Water: Summer: occasional summer
water (Water Zone 1-2 to 2)
Other: tolerates seaside conditions
California buckwheat
Blooms: May-Nov [July-Aug MNBY]
Soils: Texture: sandy to clay; well-
drained
pH: any local – 6.0-8.5
Light: full sun best
Water: Summer: occasional summer
water (Water Zone 1-2 to 2)
Other: long taproot – needs deep soil; needs to be ‘eaten back’ (fall)
© Project SOUND
Ashyleaf buckwheat
Very little known – not a heavy re-seeder in my experience
Hybridizes (like all native buckwheats)
California buckwheat
Spreads aggressively into new territories if planted there.
Hybrids with E. cinerium now spread into OR
© Project SOUND
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5936,5994,6045
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?Eriogonum+cinereum
Applications to our gardens
Locally native plants should be easier to grow than those from more different places/sites
Some plants (limited by temperature or very specific biotic relationships) are simply not feasible: often these factors are not currently known
Our gardens can be a ‘testing ground’ for some limiting factors [temperature; soil type]
We should include locally native species (from local seed) in our gardens when possible to conserve local genetic variants
© Project SOUND
Applications to our gardens
At least part of our garden space should be devoted to locally native species:
Species conservation
Ease of growth
Because they are pretty & unique (even ‘exotic’)
Provide a ‘sense of place’
A sense of how ecosystems are meant to develop over time
© Project SOUND
Cultivars: implications for our gardens and
beyond May be ‘easier to grow’
Wider tolerances
More vigorous
May have showier appearance (or other attributes that lead to their cultivation)
Consequances of garden-adapted species?
Consequences of potential for weediness?
Hybridization
© Project SOUND
‘Dana Point’ California
buckwheat – naturally-occurring
cultivar from Dana Point
Population trends over time
May reflect fluctuations in abiotic factors - and a plant’s strategies to succeed despite these fluctuations
Example: Lupine seeds & precipitation Hard seed coat – can remain in
the seed bank at least a decade
Germination strategy: not all seeds germinate at the same time
May reflect a combination of other factors, including those acting within a species
© Project SOUND
Arroyo (Succulent) lupine:
some years there’s a bumper
crop, other years none
Population ecology studies groups
Population ecology : the branch of ecology that studies
the structure and dynamics of populations.
study of population growth and factors that affect growth
Population: a group of [interbreeding] individuals
of the same species inhabiting the same area.
Can be defined at various spatial scales. Example: population of Arroyo lupine
in your garden
The population of the species in the Santa Monica Mtns
© Project SOUND
https://home.comcast.net/~sharov/PopEcol/lec1/flower.gif
As in other branches of ecology, goal is
description & prediction [discovering ‘laws’]
The major problem in population ecology is to derive population characteristics from characteristics of individuals and to derive population processes from the processes in individual organisms
© Project SOUND
https://home.comcast.net/~sharov/PopEcol/lec1/whatis.html
Forces of change in population density
Population density
A measure of the number of organisms that make up a population in a defined area.
Number of individuals (of a species) per unit of area
© Project SOUND
http://203.200.1.29/learnpremium/learnpremium/scienc~00/keysta~03/
lifepr~00/lifepr~00/thegro~00/popula~01/diagram60.gif
Births (reproduction rate)
Deaths
Immigration (propagules moving in)
Emigration (propagules moving out)
forces of change
© Project SOUND
We tend to view gardening ‘surprises’ from too close a vantage point
Oh my gosh – I KILLED THAT
PLANT
Lessons for your
garden
You can’t predict everything – we just don’t know enough (and perhaps never will!)
Birth & death happen; try to learn from ‘surprise’ events
Migration (in and out) happen; be a good neighbor – don’t plant invasives
Change is normal
Plants change with abiotic conditions (which are nothing if not unpredictable!!)
Plants change their environments in ways that we’re just beginning to appreciate – we should be surprised if our garden doesn’t change
© Project SOUND
Ecology is concerned with living things at
various levels of interaction
Population: interbreeding group of individuals of the same species
Community: all the interacting species that live in a given place at a given time
Ecosystem: a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system.
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http://king.portlandschools.org/files/houses/y2/animalmaineia/files
/species/puffin/Puffin%20webpages/ecology/Ecology.html
Why worry about providing habitat for
reptiles and amphibians?
They are cool creatures
They have as much right to live as we do
Some are locally native – and are still found even in neighborhoods
Are important part of local food webs
Eat insects, spiders
Amphibians are bio-indicators of environmental toxins
© Project SOUND http://www.world-builders.org/lessons/less/biomes/desert/hot-desert/desert_chain.gif
© Project SOUND
Some people are a little afraid of lizards…
The Western fence lizard eats beetles, flies, caterpillars, ants, other insects, and spiders.
If you're bigger than the lizard, it’s a friend; If the lizard is bigger than you....run!
Pacific chorus (tree) frog (Pseudacris regilla)
Require water for reproduction
Live in riparian habitat; also in woodlands, grassland, chaparral, pastures - even in urban areas including back yard ponds or moist places near water source
Spend a lot of time hiding under rotten logs, rocks, long grasses, and leaf litter
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Much of their diet consists of spiders, beetles, flies, ants, and other insects and arthropods.
Western fence lizard (Sceloporus occidentalis)
Found in a wide variety of open, sunny habitats, including woodlands, grasslands, scrub, chapparal, forests, along waterways, suburban dwellings
Suitable basking and perching sites include fences, walls, woodpiles, piles of rocks and rocky outcrops, dead and downed trees, road berms, and open trail edges.
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Western fence lizard
Eats small, mostly terrestrial, invertebrates such as crickets, beetles, flies, caterpillars, ants, other insects, and spider
Occasionally eats small lizards including its own species.
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http://www.solpugid.com/cabiota/western_fence_lizard.htm
They need open ground : have trouble when there are
too many weeds, plants are planted too thickly or in areas
with thick organic mulches.
Western fence lizard – likes to perch
Its preferred habitat in the wild seems to consist of low bushes, widely spaced rocks, logs, or clumps of brush.
They seem to prefer "objects upon which they could climb....Individuals were often seen basking or displaying on such objects“
If you have this lizard in your yard, you’re likely to see it – they acclimate to humans, so they’re fun to observe
© Project SOUND
http://www.humboldtherps.com/images/20080823HCHSimage-
Western_Fence_Lizard-McCloud_River-Siskiyou_County.JPG
Southern Alligator lizard (Elgaria multicarinata)
Lives in coastal sage scrub, chaparral, grasslands, oak woodlands, pinon-juniper woodlands, some pine woodlands, and forests.
In dry zones seeks plant cover near water; near human habitation, often found under wood piles, rocks, debris or native shrubs
Most abundant in natural areas in denser ground cover where there are few open spaces - it’s a hider
© Project SOUND
http://srelherp.uga.edu/jd/jdweb/Herps/species/uslizards/Elgmulmul.htm
They are not happy when
you disturb their hiding
place!
The Alligator lizard diet is what you’d
expect
Feed on wide variety of prey - anything they can catch and swallow
Insects and their larvae, especially ground beetles, grasshoppers, crickets, ichneumon wasps
Other arthropods, such as spiders (including black widow spiders), centipedes, scorpions, sow bugs
Other lizards
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Nope – not eating – this is sex
in the garden, lizard style!
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California Legless Lizard - Anniella pulchra
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If you have sandy
soil, you may see
the Legless Lizard
in your garden
Forages in loose soil, sand, and leaf litter during the day.
Eats primarily larval insects, beetles, termites, and spiders. Conceals itself beneath leaf litter or substrate then ambushes its prey.
Good Habitat: Leaf litter under trees and bushes in sunny areas. Often can be found under surface objects such as rocks, boards, driftwood, and logs. Can also be found by gently raking leaf litter under bushes and trees. Sometimes found in suburban gardens in Southern California.
http://www.wildherps.com/species/A.pulchra.html
Lizard habitat: what every creature needs
Food
Water
A place to hide, perch and sleep
A safe place to raise their young
Protection from human-related threats
Pesticides
Toxic mulches/groundcovers and other garden items
Cats (# 1 urban predator)
© Project SOUND
http://www.humboldtherps.com/images/20080823HCHSimage-
Western_Fence_Lizard-McCloud_River-Siskiyou_County.JPG
© Project SOUND
Guidelines for creating habitat for ground-dwellers
Provide dense shrub/grass cover – perching, cover & nest sites
Provide a brush pile/logs/rocks for cover
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Guidelines for creating habitat
Provide sunning spots – with cover close by Leave some areas relatively ‘human-free’ for most of the day
Providing a garden ecosystem that provides
safe food can be more of a challenge
© Project SOUND
Reptiles and amphibians are closely tied to both the
terrestrial and soil ecosystems
Mineral component
Water
Air
Organic component [5% of total]
Living organisms [10%]
Roots [10%]
Humus [80%]
© Project SOUND
Soil: much more than
‘just dirt’
http://www.physicalgeography.net/fundamentals/images/soil_breakdown.gif
http://ui.ggimgs.net/categories/536.jpg
The above- and below-ground
ecosystems are intimately
connected by a series of cycles
The soil ecosystem: just as complex as
the above-ground ecosystem
© Project SOUND
http://soils.frec.vt.edu/Strahm/Brian_Strahm___Forest_Soils_and_Ecology_Lab___Virginia_Tech_files/Worldview.jpg
But less is known about its ecology (more difficult to study)
The soil plays an essential role in recycling
Water (the soil water)
The mineral (chemical) building blocks of life
Carbon
Nitrogen
Other key minerals
The recycling is essential to all living things (plant & animal)
© Project SOUND
http://www.pikeconservation.org/soil_ecosystem.htm
How does the recycling occur?
Food webs – levels of producers, consumers
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Producers
Primary consumers
(herbivores)
Secondary consumers
(carnivores)
Another way of viewing the living world: partitioning of
resources through space and time
Leaf litter, plant litter, ‘duff’ – however you
call it it’s all good stuff
Dead plant material: leaves, bark, needles and twigs that have fallen to the ground.
The dead organic material (and its nutrients) are added to the top layer of soil, commonly known as the litter layer or O horizon ("O" for "organic").
Litter is instrumental in ecosystem dynamics, indicative of ecological productivity, and may be useful in predicting regional nutrient cycling and soil fertility
© Project SOUND
Leaf litter is FOOD and HABITAT
Some seeds only germinate (or germinate best) is leaf litter
Decomposers use the litter itself as food Earthworms
Fungi
Bacteria
Amoebae
Insect larvae
And many more
Reptiles, amphibians, birds, and even some mammals rely on litter for shelter and forage
© Project SOUND
Some butterflies &
pollinators spend a larval
stage in the leaf litter
Native plant ‘litter’ benefits the soil ecosystem
in a number of ways
Protects the soil surface from physical damage due to wind/rain etc. (natural mulch)
Moderates soil temperature swings
Conserves soil moisture
Recycles mineral nutrients back into soil (the very ones the plants have removed)
Provides food for ground-level and soil organisms
© Project SOUND
Mulch vs leaf litter Composition
May be toxic to soil organisms and/or the animals that eat them [Cedar and redwood bark fumes toxic to lizards]
May not contain ‘needed constituents’ for soil ecosystem function (often unknown because un-studied)
Not enough content complexity to support range of creatures
Depth Depth needed for weed control is
often too deep for proper ecosystem function:
Interferes with water infiltration
Breaks down too slowly
Soil too cool/dark for seeds or insect larva to emerge
Consumers can’t get to their food
© Project SOUND
What we are trying to achieve: a healthy
garden ecosystem
Water-wise (in our climate)
Life-friendly; sustains:
Humans
Other higher animals: Birds
Insects
Reptiles/amphibians
Higher plants
Other : microorganisms, others
© Project SOUND
http://upload.wikimedia.org/wikipedia/commons/a/a3/Life_Six_Kingdoms.png