ecological scales populations and life history...ecology maryland master gardeners university of...
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Dr. Sara Via, svia@umd.edu 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”
Dr. Sara Via, svia@umd.edu 2/9/2017
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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”
Dr. Sara Via, svia@umd.edu 2/9/2017
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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
Dr. Sara Via, svia@umd.edu 2/9/2017
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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”
Dr. Sara Via, svia@umd.edu 2/9/2017
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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
Dr. Sara Via, svia@umd.edu 2/9/2017
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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
Dr. Sara Via, svia@umd.edu 2/9/2017
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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!
Dr. Sara Via, svia@umd.edu 2/9/2017
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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.
Dr. Sara Via, svia@umd.edu 2/9/2017
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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)
Dr. Sara Via, svia@umd.edu 2/9/2017
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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
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