Species-of-the-Day

Wood Duck (Aix sponsa)

Brink of Extinction

By early 1900’s, culminative effects of:

1) wetland drainage (ag. expansion)

2) deforestation

3) overhunting

Habitat

• Wooded swamps & river bottomlands

• Natural tree cavities for nesting (cypress, sycamore, silver maple, black ash)

• Home range changes with flooding events

Food

* In water <18”, feed on:

- seeds of trees (e.g., acorns)

- also field grains

* Young = aquatic insects

Reproduction

Pairing in late Oct into spring (Mar-July nest)

Clutch size = 6-10 eggs

Behavior

- Dump nests (up to 30+ eggs in 1 nest) = “egg dumping” behavior = intraspecific brood parasitism

- may decrease hatch rates to 10%

Factors Determining Patterns of Habitat Use

• Competition

• Predation

Concept of Habitat Selection

• Wildlife perceiving correct configuration of habitat needed for survival – differences based on age/experience/chance? – hierarchy to decision process

• Niche concept (time/place/functional role) & habitat selection

• For example, in open habitats, bats use low-frequency / long-distance calls (ultrasound) while foraging

• Whereas, bats in closed canopy settings = constant/high frequency = detect wing beats

Hutchison’s n-dimensional hypervolume

Concept of Habitat Selection

• Hutchison = n-dimensional hypervolume as explanation of the niche

• Fundamental vs. Realized Niche

Species 1Species 2

Testing the Hutchinsonian Niche Concept of Habitat Selection• James – work with birds in Arkansas…

quantified habitat relationships

• How do birds select habitat?• niche gestalt : each species has characteristic

perceptual world…responds to that world as organized whole … search image concept

• How do we (as wildlife biologists) “see” through the eyes of wildlife species?

Wildlife Habitat Ecology & Mgt

• Habitat from an evolutionary perspective• Species distribution relative to habitat dist’n• Climatic events

• Pleistocene Epoch & dist’n of modern species

habitat interspersion –

Leopold’s Law of Interspersion

Habitat Fragmentation

1) gap formation

2) decrease patch size

3) increase isolation

4) increase edge

5) conversion of matrix

Concepts• Habitat = species-specific resources

available (relative quality)

• Habitat Use = manner in which species use resources

• Habitat Selection = hierarchical decision process (innate & learned) of what habitats to use

• Habitat Preference = based on selection of habitat, which are used more than others (preferred vs. avoided)

Concepts• Habitat Availability = accessibility of

resources

• Habitat Quality = positive relation with fitness (not just density)

• Critical Habitat = resources essential to the species….ESA designation….How is it determined?

Scale Dependence of Habitat Selection

1st Order2nd Order3rd Order4th Order

Macrohabitatvs.

Microhabitat

1st order – innate?

2nd order –decisions

3rd &4th order –decisions

Need for Multiscale Analysis

• e.g., Australian leadbeater’s possum

• landscape vs. local scales

Constraints (significance)

Level of Focus (level of interest)

Components (explanation)

Hierarchy Theory

Constraints

Why do long-tailed weasels select forest patches

and fencerowsin fragmented landscapes?

Components

Population

Community

Individual

Guild Concept• guild = group of species that exploit the

same class of resources in similar way• community guild = no taxonomic

restrictions; guild members chosen based on investigator-defined resources

• assemblage guild = guild members based on taxonomic relations

Models of Habitat Relationships• Model (assess) habitat for wildlife

species, e.g., USFWS

• Habitat Suitability Index (HSI) models

- include top 3 environmental variables related to a species’ presence, distribution, & abundance

HSI = (V1 x V2 x V3)1/3 = 0 to 1

• Yellow Warbler HSI

for different forest conditions

HSI models• useful for representing possible major

habitat factors

• true value as hypotheses

• Do not provide information on:

- population size or trend

- behavioral responses

• single-species approach

Species-of-the-Day

Kirtland’s warbler (Dendroica kirtlandii)

Habitat

NE Michigan jack pine forests

- Nesting habitat = 2-6 m (~5-20 ft) tall young jack pines (<15 yrs) = very dense stands

- Large forest stands = 100+ ha (200+ A)

2001 = 1,085 singing males = highest count since 1951

Food

Insectivores & herbivores

Reproduction

~May, late May = 5 eggs

i.p. = 13-16 days

Behavior

- Migrate to Bahamas

- Return to MI early to

mid May (males 1st)

- Influence of brown-headed cowbirds (nest parasitism)

ecotones, coverts, edges

The “Edge Effect”

Core Areas – Interior Habitat

“Not all habitat patches are the same”

• habitat-interior species

• Area-sensitive species

Countering Edge Effects & Habitat Fragmentation

• Increase edge complexity

Countering Edge Effects & Habitat Fragmentation

• Develop connective corridors

• Increase edge complexity

Linking Core Areas

& Refuges

Multiple-Use Module (MUM) Network

• Refuges (nodes) connected by corridors

Roads: Formation of Barriers in Landscapes

Species-of-the-Day

grizzly bear (Ursus arctos)

Habitat

Mississippi R to Pacific (plains, forests, mountains, wetlands, beaches)…

Today, (US, lower 48)

Montana

Wyoming

Idaho

Washington

1985 – Interagency Grizzly Bear Committee

Food

Omnivores – up to 90% plant matter

* Seasonality

Reproduction

~mid May to early July

litter size = up to 2

*delayed implantation

Behavior

Hibernation (Oct-May)