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89 Cards in this Set
- Front
- Back
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Three predictions of global warming
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1) increase temp
2) increase surface temp 3) changes in precipitation |
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Habitat vs. Ecosystem
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Habitat: physical and biuological environement used by an individual, population, species or groups of species
Ecosystem:A group of organisms and their environment (such as a lake or forest) |
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Habitat degredation vs. Loss
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Habitat Degredation: the process by which habitat quality for a given species is diminished; when contaminants reduce a species ability to reproduce in a certain area
Habitat loss: when habitat quality is so low that the environment is no longer usable |
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Ecosystem Degredation
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occurs when alterations to an ecosystem degrade or destroy habitat for many of the species that constitute the ecosystem. (ie deforestation and draining wetlands)
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Why are species more vulnerable to extinction?
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because they are more rare.
1. habitat restriction 2. small geographic range 3. small population size |
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Examples of 'risk' species
define megaphona |
1. Cave-dwelling creatures (salamanders)
- are blind, unpigmented/can't live anywhere else; have no ability to compete with other ecosystems 2. Islands, bodies of water, moutnain ranges - "barriers" depend on species 3. Predators, MEGAPHONA (large body size) - carnivores have to track across large areas |
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Why are some species more sensitive to human threats (4)?
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1. Ecological Overlap= THeir habitat overlaps ours (tallgrass praries good for farming)
2. Large Home Range Requirements (conflict with roads 3. Human Attention: we like them (pigeons, turtle soup) 4. Limited adaptation and Resilliance: Low Progeny (reproductive capacity) ex: MOA birds are flightless and breed slowly |
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Population vs. metapopulation
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Population: Group of individuals of the same species occupying the same geographic area at the same time
Metapopulation: population consisting of SUBpopulations *often patchy habitats & DISPERSAL between the patches= moving back and forth *** INTERMEDIATE ENVIRONMENT |
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Source vs. Sink populations
define: Rescue effect & turnover |
Source
1. Emigrants outward 2. Cause "rescue effect": subpopulations saved from extinction by immigration from other subpopulations 3. SENDERS Sink 1. Survived because of emigrants (can't maintain without) 2. Smaller, reoutinely populated= TURNOVER: local extinction events 3. RECEIVERS |
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Core vs. Satellite SUBpopulations
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core: subpopulations that persist for long periods of time
Satellite: subpopulations that are small and wink on and off; sink populations with rapid turnover |
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Annual Climactic Cycles
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SEASONS
- due to earth's tilt, 23.5 When we get direct input from the sun. Cancer= summer capricorn= winter |
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Equinox
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equal distance ( march and september
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Atmpsheric Climate Cycles
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Perihelion= january 3rd, closest to the sum
Aphelion= July 4th, fathest from the sun |
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Procession of the Equinoxes
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Relates to where the earth is in it's orbit around the sun when the solstices and equinoxes occur
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Other factors in climate change
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solar output
ocean currents jet stream glaciers CO2 |
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How do you know climate change has occured (3 ways)
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1. non climate data
2. direct data 3. models |
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Non climate data
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ice cores
lake and pond sediments: conifers in MO tree rings packrat middens: nuts left over tell what kind of trees coral reefs |
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Direct data
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example of CO2 levels from a hawaiin conservatory
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Use of models
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Programs that combine
-atmospheric circulation -ocean circulation atmospheric and ocean interactions -feedback maechanisms *models are tested using past climate data * only natural and Antropogenic (human) factors together give overlap |
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Things we are seeing
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melting ice/glaciers
rising sea levels vegetarian range shifts ex: beech tree range flowering times **interdependent systems may become uncoupled bleached coral reefs effects on human health (tropical disease spread) |
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Response of organisms on climate change
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-easiest option= range shift
- in general, most species have responded individualistically |
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PVA
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PVA is a technique using models to determine the likely fate of a population
Replace x values with good predictions Understand why the population will become extinct – what factors will be responsible This gives conservationists some guidance on how to direct their management |
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Problems with PVA
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These models cannot distinguish with confidence the probability of extinction over long periods
Reasonable data is hard to collect -Age-specific natality and mortality have not been measured for most species and are not easily obtained |
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4 Stochasticities
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1) Demographic
2) Environmental 3) Catastrophy 4) Genetic |
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Demographic Stochasticity
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Uncertainty resulting from random variation in reproductive success and survivorship at the individual level
Problem: In some species it is not enough to have a balanced age and sex structure Must be a large number of individuals to provide enough social stimulation for reproduction |
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Environmental Stochasticity
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**Random variation in components of habitat quality
Climate nutrients Water Cover Pollutants -Relationships with other species Prey Predators Competitors parasites Pathogens Problem: Translating these relationships into quantitative predictions becomes very complex and are limited in PVAs |
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Catastrophic Stochasticity
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Dramatic events such as droughts and hurricanes that occur at random intervals
They are a form of environmental stochasticity, but they differ in that they are discrete, specific events rather than continuous variations Effects can be greater than all other factors combined |
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Genetic Stochasticity
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Random variation in the gene frequencies of a population resulting from:
Genetic drift Bottlenecks Inbreeding/outbreeding Problem: These four factors cannot be incorporated into a model in a simple, additive fashion |
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Active Management
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Adaptive management must include activities such as:
Habitat manipulation Predator or disease control Manipulation of potential competitors Winter provisioning of food Transplanting individuals from subpopulations |
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Ways to degrade an ecosystem
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1) Human Contaminants
2) Human Modifications - soil, water, disturbance regimes (levys, fire control, draining wetlands) 3) Processes that destroy ecosystems -deforestation -desertification -Alter wetlands |
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Deforestation (why at risk)
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- resources (timber)
- land is good for development/farming -climate is benign |
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Tropical Deforestation
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-biodiversity
-take a long time to regenerate a forest's structure/complexity -soil is poor, trees hold soil, causes erosion because nutrients are in the plants, not the soil -climate is warm and most= FAST DEVOMPOSITION; leaf vegitation that hits the ground decompose quickly and plants are stuck in constant growth -human population increase in tropical areas (poverished areas) |
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Factors in forest diversity
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1. benign soil and climate
2. durability of wood= resivoire of organic matter 3. Strength of wood (verticle dimension; increased height=more niches 4. Dynamic ecosystem: when a tree falls it opens a canopy=lotws of disturbance |
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Deforestation=
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Change in structure= Change in function
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Consequences of Deforestation
-carbon sinks |
1) soil erosion
2) climate cahnge-forestws are "Carbon Sinks": CO2 take in, when burned/cut CO2 is released back into atmosphere 3) Transpiration: most of the water in trees goes right through, removal causes EVAPORESPIRATION effecting precip. |
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Desertification
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land degredation of grasslands and rangelands until they are dominated by sparce vegitation
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causes of desertification
-bulk denisty |
1) Ocergrazing: consumer/trample too many plants
-increases compaction= decreased pore space -BULK DENSITY= weight/volume. leads to erosion -burning to clear the land |
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Agriculture/Cultivation
Salinization |
-soil erosion
-has to be irrigated= flooding and drying out SALINIZATION: salit is not evaporated with water and makes soil salty |
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Consequences of desertification
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-grasslands are replaced with unpalatable brush
-change in species, loss of biodiversity, rare species lost -decreased productivity and biomass |
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Changing Hydrology (causes)
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-draining, dredging, fill of wet lands
-channeling of rivers.streams -dams/dikes |
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Why we change hydrology
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hydropower
agriculture recreation transportation kill mosquitos control flooding |
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Consequences of changing hydrology
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Destroy habitat- biodiversity
wetlands are lost** keystone habitats(play critical roles) "sponge" regular flooding Filtration (fresh H2)) |
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Ways to prevent Water Erosion
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Biological
rely on plant materials as the main structural elements in a shoreline protection system. Vegetated Armoring mimic the natural environments through the use of woody and vegetative elements Traditional Rock Seawall |
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Soil Erosion
Contour Strip-cropping |
Contour Strip-cropping
Plantings are arranged so that strips of small grains are alternated with strips of row crops. Crop rotation Tillage practices crops are grown with minimal cultivation of the soil. Terracing Topography |
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Fire
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This allows small ground cover to re-grow providing more food and nutrients.
It may be useful to not only control competing woody plants, but to also stimulate the growth of oaks, especially white oaks |
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Forest Fragmentation
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Natural landscape is broken up into small parcels of isolated ecosystems
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Ecosystem Degradation effects
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Ecosystems and habitats are routinely degraded, and sometimes destroyed by humans
These factors put stress on species and reduce over all fitness. Factors such as contamination by pollutants, movement inhibiting structures such as roads or dams, and the alteration of natural processes lead to unbalanced ecosystems. |
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Fragmentation
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natural landscape is broken up into smaller parcels of ISOLATED ECOSYSTEMS
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Attrition
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fragmentation when only very small, cery isolated patches of natural vegetation remain
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Theory of Island Biogeography
MacArthur & Wilson Define: Mangrove |
1) Rate of immigration
-distance from a source of immigrants 2) Rate of extinction -island size Mangrove: neted island, fumegarted to see how it would colonize |
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Conceptual framework to understand fragmentation
(2) define: area sensitive |
1) small fragments have fewer species than large fragments
- larger have greater variety=more niches -both common and rare species likely -smaller=smaller population size and some are AREA SENSITIVE: do not occur in small patches of habitat 2) More isolated fragments have fewer species than less isolated -relatively few inddividuals immigrate into an isolated fragment -visiting an isolated fragment is inefficient |
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Causes of Fragmentation
fundamental vs. proximal cause |
Proximal Cause:agriculture, urban development
Fundamental Cause: Expanding human population |
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Consequences of Fragmentation
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-destsruction of ecosystems
-loss of "area sensitive species" -effects dispersal & ability to adapt to climate change -may convert a population into a metapopulation -may effect fire/other disturbance -increases edge species (turkey and deer) * drastically reduces interior species |
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Types of Overexploitation
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1. Commercial Exploitation
-sell and trade 2. Subsistence Exploitation -Use directly meets personal needs of people such as: food, shelter, tools, clothes 3. Recreational Exploitation -Hunting, often beneficial 4. Incidental Exploitation -In the process of exploiting one species, other species are incidentally exploited as well (ex: by catch; organisms not intended to be caught in nets) 5. Indirect Exploitation -Human activities that indirectly kill other organisms Roads, fences, developments, and antennas |
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Define Overexploitation
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Exploiting a resource to a point that the species or resource is not sustainable
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Example of Overexploitation
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Sea Cow
Discovered in 1741 Used as food, the sea cow was at least 26 feet long and weighed 8-10 tons When discovered they were thought to be numerous and traveled in herds Later discovered that there were less than 1500 Sea Cows. Sea Cows also had a limited range Extinct in 1768 |
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Example of Overexploitation
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Macaw
Their has been a recent demand in the pet market for Macaws This lead to nest raiders which created a destruction of breeding sites as well as environment destruction around breeding site 9 out 16 Macaw species threatened |
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Consequences of Overexploitation
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1.Population Effects
Not all individuals created equal (Age, Sex, Genetic Structure) 2.Ecosystem Effects -Keynote Species extinction or endangerment -Overhunting -Seed Distribution -May become extinct with respect to their ecological function before they are actually extinct |
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Managing Overexploitation
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The Endangered Species Act
Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Agreement between governments that is used to protect endangered species of plants and animals to not be internationally traded |
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Stages of Invasion
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Invasive species must
1. grow 2. reproduce 3. dispersive propogules (seeds) 4. Colonize new terrotories |
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Invasive species must overcome Barriers
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1. geographic
2. resource 3. environmental 4. dispersal |
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The tens Rule
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about 10% of nonnative species escape to the wild
- of these, 10% become established --of these, 10% disperse widely enough to survive stochastic environmental events ---of these, about 10% significantly impact the natural area |
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Stages of Invasion
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1. Introduction
2. Establishment 3. Lag Time 4. Spread 5. Invasion |
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Stages of Invastion
INTRODUCTION Propagule Pressure |
* Plants first have to overcome geographic barriers.
How? - both intentional and unintentional - most arrive via humans -accessible habitats particularly at risk -Propagule Pressure: improves the likelihood of introduction * the number of individuals of a species that is released |
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Stages of Invastion
ESTABLISHMENT what must overcome? how overcome? |
* Once arrived, must encounter favorable environmental factors
Barriers= -stochastic events (flooding, etc) -small population size How? -repeated introductions -marketing-public acceptance of non-native species |
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Stages of Invastion
LAG TIME define species profiles |
-time between introduction and rapid expansion
-underscores the need for * close monitoring of potential invaders * Species profiles: variation betwene a potential invader's new and native habitat *it's history of immigration -lag times vary -often associated with a sudden spread |
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What causes a sudden release (associated with lag time) 3 things
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1) genetic adaptations allow the species to overcome environmental barriers
2) Environmental barriers to invasion are removed via disturbance, stress, or biotic interaction with other speicies 3) Observation and monitoring techniques fail to detect population growth at an early invasion stage. |
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Stages of Invastion
SPREAD criteria? |
Criteria:sustains itself over selveral life cycles without human intervention
-likelihood of eradication by stochastic events is low -barriers are typically dispersal limitation |
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Rate of Spread positively correlates with
-Taxonomic Isolation -Habitat Matching |
1. abundance of species in it's native range
2. it's global distributal (wide tolerance) 3. Degree of Taxonomic Isolation: freely hybridizing (oaks) 4. Degree of Habitat Matching: new and old conditions meet 5. availability to human-made structures facilitating spread -the presence of other nonnative species |
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Stages of Invasion
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1) Criteria
- self perpetuiation -undergos a series of widespread dispersal -becomes incorporated within resident flora (all other plant life) 2) Non-invasive unless: - have been dispersed frmo parent plant at a distance of more than 100m <5 years or more than 6 m per 3 years |
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What must invasion overcome?
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1) dispersal barriers
2) adjust to a braod range of biotic and abiotic pressures *eradication at this stage with limited resources is virtually impossible |
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management strategies for invasive species
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1) limit spread
2) monitoring known populations |
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How Invasive species move
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Stow aways: unwanted organisms (mostly from ships ie smallpox)
Subsistence & Commerce Recreation Aesthetics, because we can Science Biological Control Habitat Change |
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Stages of Invasion
EQUILIBRUIM |
rate of expansion slows at equilib. Caused by:
- occupy suitable habitat -abiotic/biotic pressures -management/control strategies |
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Key Predictors of Invasiveness
Species-based attributes define fitness homeostasis & Phenotypic plasticity |
- initial population size
- number of introductions - invasion success history -effective dispersal mechanism - Fitness homeostasis= maintaining constant offspring -braod geographic range Phenotypic plasticity= phenotype is alterable -competitive ability -reproductive strategies ** does not need all to be invasive, just a few |
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Community-based attributes
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-all communities are invasible
some may be more suseptable - certain environmetal factors increase probability of successful invasion (ie human modifications -novel life forms -vacant niche hypothesis -enemy release hypothesis: release from preditors -resource availability -invasion meltdonwn |
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Invasion Theory & management
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General Rule: Species that are invasive in one part of teh world are likely to become invasive in another
-there is no single traits that determines invasiveness -all sites are susceptable but some are more than others -managers must be aware of activites that facilitate invasion |
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5 Types of Damage from Invasive Exotics
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Predators and Grazers
Parasites and Pathogens Competitors Hybridization Ecosystem Effects |
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Predators and Grazers
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-Grazers primarily concern agriculture, especially insects
-They can also have negative effects on biodiversity *This is especially true on islands |
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Parasites and Pathogens
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Human health are of special concern
European diseases killed far more Native Americans than did European bullets Humans are not the only Typically brought to an area through an infected animal |
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Competitors
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Easier to observe in organisms with a sedentary lifestyle
Zebra mussels, kudzu, etc. This can also occur when space is not an issue for animals |
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Hybridization
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Can cause loss of genetic diversity
Genetically modified organisms are of concern due to the difficulty in keeping them from breeding with nearby wild relatives Can result in genetic swamping Genes of one species come to dominate a common gene pool Could disrupt the evolution of new species |
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Ecosystem Effects
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Invasive species can alter a variety of ecosystem properties:
Productivity Nutrient cycling Natural disturbance regimes Soil and vegetation structure |
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exotic
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species living outside it's native range
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introduced species
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a species move by humans outside it's native range
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non-indigenous species
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term used to describe species living outside of it's native range
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non-native species
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same as non-native
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alien plant
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botanists; plant species living outside native range
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invasive species
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exotic populations expanding rapidly
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