moriver floodplain forest ecology moriverclasses 10-11-11

8/3/2019 MoRiver Floodplain Forest Ecology MoRiverClasses 10-11-11

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Floodplain ForestFloodplain Forest

EcologyEcology

Mark Dixon

Introduction to River Studies

October 11, 2011


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OutlineOutline

Key concepts, functions, andKey concepts, functions, and

processes in riparian zonesprocesses in riparian zones

Interactions of plants withInteractions of plants withriver processesriver processes

Historic landscape andHistoric landscape and

vegetation changevegetation change

Future trends?Future trends?


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Riparian of or belonging to the bank of a riverof or belonging to the bank of a river The interface or ecotone between aquatic andThe interface or ecotone between aquatic and

upland ecosystemsupland ecosystems

Floodplain Level land periodically submerged byLevel land periodically submerged by

floodwaters, or a plain built up by streamfloodwaters, or a plain built up by stream

deposition (Stromberg & Tellman 2009)deposition (Stromberg & Tellman 2009)

Some DefinitionsSome Definitions


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San Pedro River, Arizona, National Geographic Magazine

Filter, buffer, ecotoneFilter, buffer, ecotone Protect aquatic resources from pollutionProtect aquatic resources from pollution

Linkages between terrestrial and aquaticLinkages between terrestrial and aquatic

Functions of Riparian ZonesFunctions of Riparian Zones


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From Baxter et al. 2005

Functional Role of Floodplains:Functional Role of Floodplains:

Aquatic-Terrestrial Food WebsAquatic-Terrestrial Food Webs


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Ecosystem Services/EcologicalEcosystem Services/Ecological

Functions of Riparian ForestsFunctions of Riparian Forests


7/50San Pedro River, Arizona, National Geographic Magazine

Filter, buffer, ecotoneFilter, buffer, ecotone Protect aquatic resources from pollutionProtect aquatic resources from pollution

Linkages between terrestrial and aquaticLinkages between terrestrial and aquatic

Functions of Riparian ZonesFunctions of Riparian Zones

CorridorCorridor Organism movements, population viabilityOrganism movements, population viability

Upstream-downstream linkagesUpstream-downstream linkages

Biodiversity hotspotBiodiversity hotspot High diversity of species and habitatsHigh diversity of species and habitats


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Riparian Pattern and ProcessesRiparian Pattern and Processes

Important processesImportant processes:: Physical:Physical:

Movement of water and sedimentMovement of water and sediment

BiologicalBiological Movement, colonization, survival/mortality,Movement, colonization, survival/mortality,

reproduction, adaptationreproduction, adaptation

CharacteristicsCharacteristics:: Temporally DynamismTemporally Dynamism

Spatially DiversitySpatially Diversity


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Morphology, Dynamics of aMorphology, Dynamics of a

Braided RiverBraided River


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Morphology, Dynamics of aMorphology, Dynamics of a

Meandering RiverMeandering River


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Habitat Diversity Driven byHabitat Diversity Driven by

Fluvial Geomorphic ProcessesFluvial Geomorphic Processes


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Alluvial LandformsAlluvial Landforms

From Naiman et al. 2005


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Vegetation patterns influenced byVegetation patterns influenced by

river processesriver processes

Oldman River, Alberta, Canada

From Naiman et al. 2005 (photo from Stewart Rood)


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Vegetation influences river processesVegetation influences river processes

From Naiman et al. 2005

Large Woody Debris, Queets River,Washington


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Platte River

NEED NEW SLIDES PHRAGMITES

ALSO NEED SOME SUMMARY TEXTSLIDES FOR BOTH???AT LEAST GIVE STUDENTS AN OUTLINE


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Opportunities and Stresses for PlantsOpportunities and Stresses for Plants

in River/Floodplain Environmentsin River/Floodplain Environments

Stresses/ChallengeStresses/Challengess Too wetToo wet

flooding, low oxygen levels in soils, etc.flooding, low oxygen levels in soils, etc.

Instability and physical disturbanceInstability and physical disturbance erosion, deposition, physical force of water, rapid changeerosion, deposition, physical force of water, rapid change

CompetitionCompetition

Opportunities:Opportunities: Open habitats, low competition, high moisture andOpen habitats, low competition, high moisture and

sunlightsunlight


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ResilienceResilienceAbility to re-sprout after burial or flood damage, rapid growthAbility to re-sprout after burial or flood damage, rapid growth

EnduranceEnduranceTolerate inundation, low oxygen levels, burial, low nutrients,Tolerate inundation, low oxygen levels, burial, low nutrients,

drought, high shear stressdrought, high shear stress

Colonization abilityColonization abilityDispersal by wind and water, vegetative reproductionDispersal by wind and water, vegetative reproduction

Timing of seed release in relation to flood timingTiming of seed release in relation to flood timing

Reproduction may be depend on flooding & fluvial landformsReproduction may be depend on flooding & fluvial landforms

Competitive abilityCompetitive ability

Plant Adaptations to RiparianPlant Adaptations to Riparian

EnvironmentsEnvironments


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Stresses and Opportunities for PlantsStresses and Opportunities for Plants

Vary Across the Riparian ZoneVary Across the Riparian Zone

Drier conditions, less frequent

floods, finer soils, greaterdepth to water table

Wetter conditions, more

frequent floods, coarser soils,shallower depth to water table


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3 strategies (Grime) R = Ruderals (High Disturbance, Low Stress)R = Ruderals (High Disturbance, Low Stress)

Rapid growth, early reproductionRapid growth, early reproduction

High investment in repro. & produce many small seedsHigh investment in repro. & produce many small seeds

S = Stress-tolerant (Low Disturbance, HighS = Stress-tolerant (Low Disturbance, HighStress)Stress) Slow growth, conserve nutrients and waterSlow growth, conserve nutrients and water

May invest in defense against herbivoresMay invest in defense against herbivores

C = Competitive (Low Disturbance, Low Stress)C = Competitive (Low Disturbance, Low Stress) Growth limited more by competition for space andGrowth limited more by competition for space and

resources than by environment directlyresources than by environment directly

Strong ability to exploit resources in face of competitionStrong ability to exploit resources in face of competition

Plant Life History StrategiesPlant Life History Strategies

P tt i Ti d S bP tt i Ti d S b


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Patterns in Time and Space may bePatterns in Time and Space may be

relatedrelatedFrom Richter and Richter

2000


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directional, cumulative change in the speciescomposition of vegetation at one location over thecourse of about 1-500 years. (Barbour et al.)

the change in plant, animal, and microbialcommunities in an area following disturbance orcreation of new substrate. (Molles)

A hypothetically orderly sequence of changes in

plant communities leading to a stable climaxcommunity. (Langston)

SuccessionSuccession


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Disturbance:Disturbance: a relatively discrete event that disrupts thestructure of an ecosystem, community, or

population, and changes resource availability or

the physical environment.(Turner et al. 2001, Pickett and White 1985)

Examples:Fire, flood, high wind, earthquake, volcano, severe insect

infestation, etc.


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Modification of environment by organisms Plants create shade, litter, modify microclimate, change

soil structure and chemistry

Influences of plants on each other Competition for light, nutrients, moisture, space

Species traits & population processes

Gradual replacement of colonizing species (R) withcompetitive (C) ones that can continue to establish

Important Mechanisms inImportant Mechanisms in

SuccessionSuccession


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Seral / Successional stages

Pioneer / early successional species

Good colonizers (Ruderal species)

Late successional species

Good competitors

Climax community when no furtherdirectional change in species composition

Outdated concept?

Succession - TermsSuccession - Terms


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(adapted from Johnson 1992)

Mathematical Model of Succession in

Missouri River floodplain forests


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River meanderingRiver meandering

creates seedbedscreates seedbeds

for cottonwood &for cottonwood &

willowwillow

establishmentestablishment


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Sandbar WillowSandbar Willow

((Salix interiorSalix interior))


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Peachleaf willow(Salix amygdaloides)


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Plains CottonwoodPlains Cottonwood

((Populus deltoidesPopulus deltoides))


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Large spring floods move and depositLarge spring floods move and deposit

sediment, preparing bare surfaces suitable forsediment, preparing bare surfaces suitable forseedling growthseedling growth

Slowly receding floodwaters deposit seedsSlowly receding floodwaters deposit seedsand provide moisture for growthand provide moisture for growth

Timing of floods and recession must coincideTiming of floods and recession must coincidewith when seeds are releasedwith when seeds are released

Cottonwood and willow establish afterCottonwood and willow establish afterfloods of appropriate size and timingfloods of appropriate size and timing


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Changes inChanges in

CompositionComposition

With forest age:

Declines in

cottonwooddominance

Increasedabundance ofother species


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Box elder(Acer negundo)

Later Successional Species


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American elm

(Ulmus americana)


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Dutch ElmDisease


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Green ash(Fraxinus pensylvanica)


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Emerald Ash Borer


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HackberryCeltis occidentalis)

B k (Q


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Bur oak (Quercusmacrocarpa)


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Native and Non-native

Invasive Species

E t d d


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Eastern redcedar(Juniperus virginiana)


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White mulberry (Morus alba)


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Common buckthorn(Rhamnus cathartica)

Russian olive(Elaeagnus

moriver floodplain forest ecology moriverclasses 10-11-11

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