Ecology of Wildlife Pwpt 3

modifications to ecosystem

• internal

  • individual

    • aging into a mature forest

  • longer term genetic responses

    • evolution

• external

  • climate change

  • natural impacts

  • lightning, fire, drought, volcano, hurricane

  • human impacts

energy transfer

• 10% rule of thumb

  • only 10 of the energy from one level moves on to the next level 

• excess energy available

  • weight gain possible

  • reproduction possible 

biomass transfer

• not all energy goes into biomass, not comparable to energy transfer 

• 10% rule does not apply

habitat

• an area with the combination of resources and environmental conditions that promotes residency by individuals of a given species and allows them to survive and reproduce 

• habitat type = particular vegetative community 

• varies in quality and impacts potential for reproduction

  • appropriate habitat selection improves survival and reproductive success 

• fundamental to wildlife management

  • all species need a place to live

  • populations can recover in good habitats

• habitat loss is the number one global threat to wildlife 

habitat selection

• how elements of habitat resources are used in relation to their availability 

• wildlife biologists: identify the characteristics of a location that are important to species 

habitat quality

• individuals stay where necessary resources in an area reach crucial levels of abundance 

• the adult breeding population has a hold on the most optimal conditions

• resources needed may not have equal quality

  • may be sufficient for survival but not for repro

• differences in repro and survival are not related to genetics but are a reflection of habitat quality

  • performance of a population is an indicator of habitat quality

• high quality habitat 

  • = high population densities, survival, repro 

  • will be inhabited first 

• other factors can be involved, like predation

range of tolerances

• organisms live within physical and biological limits - range of tolerance

• may be narrow, may be broad

  • steno = narrow

  • eury = broad

    • white tailed deer are eurythermal 

• knowing these limitations is important when moving animals to new locations

ecological traps

• human altered environment cues used by wildlife to select habitat may not result in high survival/repro

• cues can be misleading

  • Non-native plants may promote survival, but inhibit reproduction—Cotton rat and Lehmann lovegrass (non-native)

• cues can reduce demographic success

  • Human activities may increase mortality or reduce reproduction

    • Roads & trains—increase mortality (elk in PA)

    • Mowing—destroys ground nesting bird’s nests

    • Utility poles electrocution of birds of pry

• Wildlife have had insufficient evolutionary time to adapt to threats from human activities

limiting factors

• resources that may be in short supply and which limit the number of individuals

• Resources required may be of many different types and may seasonal

• If we can increase that resource, perhaps the habitat can support a larger population

  • A wood duck box may not look like a tree with a cavity, but the nest box opening and internal measurements may well mimic the requirements of the duck and are readily accepted as a substitute

  • wood duck = behavioral plasticity

Niche

• functional role and position of the organism in its community

• help to reduce competition between species

  • temporal separation, location separation

  • Spruce grouse feed on jack pine needles in winter

  • Ruffed grouse may be found in the same area, but feed on buds of deciduous trees in winter—different feeding niches (niche separation)

• profession and address

  • what do you do, where are you

• evolution driven

  • physical and biological factors provide the fit 

ecological equivalents

• demonstrates convergent evolution

  • don’t have to be related to be ecological equivalents

  • similar evolutionary forces 

• scots pine and capercaillie

  • ecological equivalents to jack pines and spruce grouse 

niche partitioning

• same food source, not necessarily in the same niche!

• temporal, altitude, habitat

  • where on the tree are you eating from

• browsers, inbetweeners, grazers

niche partitioning: examples

• Robins and American woodcock 

  • both feed on worms but in different habitats and at different times

• Insectivorous bats and birds 

  • feed at different times

• Wildebeest and topis 

  • feed on different parts of the same food

• Herons & egrets 

  • often nest in the same vegetation, but at different heights

managers must ensure that the habitats of a target species match the niche requirements (4)

• managers can

  • augment or maintain habitat

    • Grazing area

    • Nesting sites

    • Thermal cover

    • Water sources

  • reduce competition

  • reduce predation

  • eliminate or reduce impact of exotics/invasives

Bog turtle

• endemic to Eastern US

• requires bog habitat

  • put cattle on the land

• large ungilates once prevented succession

  • good thing for the bog turtle

ecological succession

• comminutes change in a sequential process

• different, sequential communities occupy the site until a climax community is reaches

  • dynamic equilibrium that persists over time

• pioneer community

  • first step

• climax community

  • final step

  • old growth forests

• primary succession

  • occurs when there was no community before

    • volcanic island

    • glacier recession

• secondary succession

  • remnants remain of previous community

    • fire

    • clear cutting

wildlife management and succession

• select a specific point in succession that benefits that species

• setting back succession

  • ax, cow, match, and plow

  • Aldo Leopold

• species associated with climax communities

  • generally do not do well

  • due to human activities

  • black-footed ferret

  • passenger pigeon

  • Allegheny woodrat

• species associated with early to mid succession

  • tend to fair better

diversity

• number of species

stability

• relative constancy of the abundance of populations

low diversity communities

• generally unstable

  • tundra

    • lynx and hare boom and bust

high diversity communities

• generally stable

• topical rainforests

  • large diversity, low population numbers, stable if left undisturbed

diversity and latitude

• small areas

  • isolation

  • different elevation levels