Species-of-the-Week 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

Concept of Habitat Selection Wildlife perceiving correct configuration of habitat needed for survival – differences based on age/experience/chance? – Niche concept

Concept of Habitat Selection Hutchison = n-dimensional hypervolume as explanation of the niche Fundamental vs. Realized Niche Species 1 Species 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 :

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….

Scale Dependence of Habitat Selection 1 st Order 2 nd Order 3 rd Order 4 th Order Macrohabitat vs. Microhabitat 1 st order – innate? 2 nd order –decisions 3 rd &4 th order –decisions

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 = (V 1 x V 2 x V 3 ) 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

Emergence of Landscape Ecology Equilibrium View Constant species composition Disturbance & succession = subordinate factors Ecosystems self-contained Internal dynamics shape trajectory No need to look outside boundaries to understand ecosystem dynamics Structure Function ? ? ? ?

Emergence of Landscape Ecology Dynamic View Disturbance & ecosystem response = key factors Disturbance counter equilibrium Ecosystems NOT self- contained Multiple scales of processes, outside & inside Essential to examine spatial & temporal context Structure Function

Scale What’s the big deal? Seminal pubs –Allen & Starr (1982) – Hierarchy: perspectives for ecological complexity –Delcourt et al. (1983) – Quaternary Science Review 1: –O’Neill et al. (1986) – A hierarchical concept of ecosystems

Ecological Scaling: Scale & Pattern Acts in the “ecological theatre (Hutchinson 1965) are played out across various scales of space & time To understand these dramas, one must select the appropriate scale Temporal Scale Spatial Scale Fine Short Coarse Long Recruitment Treefalls Windthrow Secondary Succession Species Migrations Speciation Extinction Fire

Ecological Scaling: Scale & Pattern Different patterns emerge, depending on the scale of investigation American Redstart Least Flycatcher American Redstart Least Flycatcher Local Scale (4 ha plots) Regional Scale (thousands of ha)

Ecological Scaling: Components of Scale Grain: minimum resolution of the data –Cell size (raster data) –Min. polygon size (vector data) Extent: scope or domain of the data –Size of landscape or study area

Ecological Scale Scale characterized by: –grain: smallest spatial resolution of data e.g., grid cell size, pixel size, quadrat size (resolution) Fine Coarse

Ecological Scale Scale characterized by: –extent: size of overall study area (scope or domain of the data) Small Large

Ecological Scaling: Components of Scale Minimum Patch Size: min. size considered > resolution of data (defined by grain)

Ecological Scaling: Definitions Ecological scale & cartographic scale are exactly opposite –Ecological scale = size (extent) of landscape –Cartographic scale = ratio of map to real distance

Scale in Ecology & Geography ecological vs. cartographic scale EcologyGeography Small (Fine) Fine resolution Small Extent Coarse resolution Large Extent Large (Broad) Coarse resolution Large extent Fine resolution Small extent

Scale in Ecology & Geography ecological vs. cartographic scale –e.g., map scale 1:24,000 vs. 1:3,000 fine vs. coarse large vs. small extent

1:24,000 1:200,000

Ecological Scaling: Components of Scale Grain and extent are correlated Information content often correlated with grain Grain and extent set lower and upper limits of resolution in the data, respectively.

Ecological Scaling: Components of Scale From an organism- centered perspective, grain and extent may be defined as the degree of acuity of a stationary organism with respect to short- and long-range perceptual ability

Ecological Scaling: Components of Scale Grain = finest component of environment that can be differentiated up close Extent = range at which a relevant object can be distinguished from a fixed vantage point Fine Coarse Scale Extent Grain

Ecological Scaling: Components of Scale From an anthropocentric perspective, grain and extent may be defined on the basis of management objectives Grain = finest unit of mgt (e.g., stand) Extent = total area under management (e.g., forest)

Ecological Scaling: Components of Scale In practice, grain and extent often dictated by scale of available spatial data (e.g., imagery), logistics, or technical capabilities

Ecological Scaling: Components of Scale Critical that grain and extent be defined for a study and represent ecological phenomenon or organism studied. Otherwise, patterns detected have little meaning and/or conclusions could be wrong

Scale: Jargon scale vs. level of organization Space - Time Individual Population Community

Ecological Scaling: Implications of Scale As one changes scale, statistical relationships may change: –Magnitude or sign of correlations –Importance of variables –Variance relationships

Implications of Changes in Scale Processes and/or patterns may change Hierarchy theory = structural understanding of scale-dependent phenomena Example Abundance of forest insects sampled at different distance Intervals in leaf litter,

Implications of Changes in Scale Insects sampled at 10-m intervals for 100 m

Implications of Changes in Scale Insects sampled at 2000-m intervals for 20,000 m

Identifying the “Right” Scale(s) No clear algorithm for defining Autocorrelation & Independence Life history correlates Dependent on objectives and organisms Multiscale analysis! e.g., Australian leadbeater’s possum

Multiscale Analysis Species-specific perception of landscape features : scale-dependent –e.g., mesopredators in Indiana Modeling species distributions in fragmented landscapes

Hierarchy Theory Lower levels provide mechanistic explanations Higher levels provide constraints

Scale & Hierarchy Theory Hierarchical structure of systems = helps us explain phenomena –Why? : next lower level –So What? : next higher level minimum 3 hierarchical levels needed

Constraints (significance) Level of Focus (level of interest) Components (explanation)