ecological scales populations and life history...ecology maryland master gardeners university of...

Dr. Sara Via, [email protected] 2/9/2017

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Ecology

Maryland Master GardenersUniversity of Maryland

Extension

Ecology – the study of how organisms interact with each other and their environment

Photo by Sylvan Kaufman

Ecological Scales Populations and Life History

Photo by Sylvan Kaufman

Population ‐ group of individuals of same species that interact and are somewhat separate from other such groups

Populations and Life History

Plant life History:‐ pattern of survival (annual, biennial, perennial)‐ timing of reproduction (once or many times, early

or later in lifetime)‐ reproductive allocation (many small seeds, few large

seeds)‐ mating system (inbreeding, outcrossing)

Different combinations of traits produce best performance in particular environment plant diversity

Pattern of survivalAnnual:

‐ live only one year,‐ invest heavily in reproduction‐ little investment in roots, storage

but, many are “self seeding”


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Pattern of survivalShort lived perennial – i.e., biennial

‐ live 2‐3 years‐ flower in second

or third year‐ often grown as annual

Pattern of survivalLong‐lived perennial

‐ live > 3 years‐ may take several years to

flower‐ invest in roots and energy storage to survive winter

Timing of reproductionGrow fast, produce many seeds quickly, then die‐ annual weed strategy‐ “colonizing species”

Wait to produce seeds until larger‐ biennials, may flower first year, then fewer flowers the next yearOr, just wait till year 2

‐ perennials

Reproduce once or many times?

Pattern of reproductionMany small seeds‐ often wind dispersed

A few large seeds‐ often animal dispersed, but…‐ Investment in reward

Mating systemInbreeding‐ selfing, transfers own pollen‐ often flowers are inconspicuous‐ don’t show inbreeding depression

Outcrossing‐ needs pollen from another individual‐ transferred by water, wind, pollinator‐ if pollinator, showy flowers‐ usually show inbreeding depression

Mating systemMixed mating

Some self‐pollinatingflowers

Some outcrossed flowers

“reproductiveassurance”


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Population growth depends on life history

Usually: Short lived species Longer lived species“density independent” “density dependent”usu. resource limited limited by biotic interactions

Ecological Niche

Niche – the unique combination of habitat & resources used by a species.

- other organisms are part of the niche

Evolution by Natural Selection- Process that “fits” organisms to environment- Occurs in populations (not in individuals)- Produces genetic changes over time

Evolution occurs when:1. Individuals within a population vary in some

trait2. Individuals with particular trait values survive

or reproduce better than others3. “Successful” trait values inherited by offspring

Plant & Animal Breeding=Evolution by Artificial selection

1. Individuals within a population vary in some trait desirable to humans

2. Only individuals with desirable traits areallowed to reproduce

3. If desirable trait is genetically based, then “selected” population will increasingly have desired traits

Domestication of Corn Illinois corn oil experimentLongest continuous artificial selection: 1896‐Increased oil content far beyond natural range


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PolyploidyBreeders cause doubling of genetic material from2 copies of each gene (2n) to 4n, 6n, 8n

Many ornamentals and crops are polyploid—bigger fruits, showier flowers, bigger and more seeds

Ornamentals: Straight species, cultivars, hybrids

Echinacea ‘Art’s Pride’E. purpurea x E. paradoxa

E. purpurea‘Magnus’

Echinacea purpurea

Echinacea paradoxa Photos from Missouri Botanical Garden PlantFinder

Genetically modified organisms (GMOs)

Move genes between species to provide- resistance to insects (“Bt”)

- resistance to herbicides (“Roundup-Ready”)

- some “desirable” attribute, such asfailure to brown in apples

Good or not?? Depends on the trait!

What is a community?

• An association of interacting populations

– Group of species (animals & plants) found in a particular area or habitat

Sometimes communities defined by function

Pollinators

Mycorrhizae

Dispersers

ParasitePhotos by Sylvan Kaufman and frowww.wikipedia.org

Community Structure

Food webs

show where

different

organisms

“fit in”


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Factors regulating community structure• Abiotic Factors

– Environmental gradients (e.g. H20, nutrients, light, temperature)

Factors regulating community structure

– Catastrophic Disturbance

But biotic interactions may often be most important

Factors regulating community structure

Biotic interactions

Competition (between species)

Predation

Parasitism

Mutualism

Detritivores take it back to the start

(Detritus = dead organisms, waste products etc.)

decomposers

Trophic “levels”

Food webs show interactions in community

Northern Forest

Succession

Secondary succession the orderly and predictable replacement of species over time.

Species depend on location, but generally goes from simple to more complex

Primary succession issoil building


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Ecological Succession

Old field successionEcological Scales

Terrestrial Biomes

Image from www.somers.k12.ny.us

Maryland’s Physiographic Regions

Watershed

Image from www.dnr.state.md.usCheck out the EPA Surf Your Watershed web site

https://cfpub.epa.gov/surf/state.cfm?statepostal=MD

Land Use in Maryland

Map from www.geog.umd.edu


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Connections in the Landscape

In a largely urban/suburban landscape, organisms need ways to get between conserved areas.

Maryland’s Green Infrastructure and Open Space programs

Targeted Ecological Areas– priorities for conservation funds‐‐chosen for conservation potential and connectedness

Ecological Scales Ecosystems: what cycles, what doesn’t?

• Nutrients (C, N, P) cycle–

used over and over again.

• Water cycles– also reused.

• Energy doesn’t cycle‐

comes from the Sun,

leaves as heat.

Energy Flow

Energy is captured in photosynthesis by primary producers

Primary Production

Cyanobacteria

Green Algae

Protists

Kelp

Plants

• Without these

guys, no lions

tigers or bears!


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Energy flow

Detritivores & decomposers recycle nutrients

Heat lost through respiration

Food webs all have the same elements:

1. Decomposers and detritivores

2. Primary producers3. Herbivores4. Carnivores5. Top carnivore

(optional)

At each level, energy is lost to respiration (just to keep the organisms at that level alive)This limits the number of levels in a food web

Energy is lost at every trophic level!

HEAT

Not much left by thetime we get to the top predator!

decomposers

This limits the number of levels in a food web

At what level is energy and biomass is highest???

Energy is lost at every trophic level!It takes 9 pounds of feed to get 1 pound of beef!

(not to mention the water required)

If food is scarce, eat low on the food web!

Let the plants poweryou directly

Nutrients: The Carbon Cycle

captured!

Carbon chains arebackbone of allorganic molecules

We can only get C for new organismsthrough photo‐synthesis!

Why is CO2 increasing? More combustion!Less photosynthesis!

1

2

Chop, chop

>99%

The Nitrogen cycle

Captured!Without bacteriano nitrogen cycle

N also releasedby power plantscar exhaust, etc.


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The Phosphorous cycle The P cycle & eutrophication

Ponds and lakes become clogged with algae. When algae dies decomposing bacteria use up all the oxygen==> dead zone!

The Water Cycle

Deep aquifersDeep aquifers

Freshwater is a limited resource!

The Water Cycle– human impacts

Billions of gallons removed from deep confined aquifers every day.

Can it refill at the same rate? No way

We are all on this globe together!

The science:

We can’t alter the balance of

plants, soil, water & nutrients

without affecting “ecosystem

services” (i.e., cycles)


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Global Warming, 1884 – 2011

Difference from 1951 – 1980 Average

- 2° C + 2° C0°Source: NASA Goddard Space Flight Center Scientific Visualization Studio

- variation through time- variation across space

This is EVIDENCE, not opinion

Severe Weather

“Global warming is contributing to an increased incidence of extreme weather because the environment in which all storms form has changed …”

Dr. Kevin Trenberth

National Center for Atmospheric ResearchJune 2011

-warmer air-warmer ocean-more water vapor in air-higher sea level

This is the New Normal

Sea level rise in Maryland

Maryland Commission on Climate Change, 2013

- 2’ by 2050- 3-6’ by 2100

plus storm surge up to 30’

Climate change and sea level rise2006 flood at Adkins Arboretumin Ridgely, MD

Credit:Sylvan KaufmanFells Point 2012

Shaded areas<5’ abovemean high tide

The NEW NORMAL for Gardens

1. More CO2: Is this a benefit?

2. Rising temperatures- warmer winters, earlier springs- more extremely hot days, fewer cool nights- increased temperature variability

The NEW NORMAL for Gardens

3. Heavier downpours, more severe weather

4. More possibility of drought

5. Possibility of salination

We are the first generation that can’t look to

historical records for garden planning

Thanks: Dr. David Wolfe, Cornell Horticulture

ecological scales populations and life history...ecology maryland master gardeners university of...

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