Species-of-the-Week

1. Species-of-the-Week • Wood Duck (Aix sponsa)

2. Brink of Extinction By early 1900’s, culminative effects of: 1) wetland drainage (ag. expansion) 2) deforestation 3) overhunting

3. Habitat • Wooded swamps & river bottomlands • Natural tree cavities for nesting (cypress, sycamore, silver maple, black ash) • Home range changes with flooding events

6. Food • * In water <18”, feed on: • - seeds of trees (e.g., acorns) • - also field grains • * Young = aquatic insects

7. 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%

8. Factors Determining Patterns of Habitat Use

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

11. Concept of Habitat Selection • Hutchison = n-dimensional hypervolume as explanation of the niche • Fundamental vs. Realized Niche • Species 2 • Species 1

12. Testing the Hutchinsonian Niche Concept of Habitat Selection • James – work with birds in Arkansas…quantified habitat relationships • How do birds select habitat? • niche gestalt :

13. 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

15. habitat interspersion – Leopold’s Law of Interspersion

16. Habitat Fragmentation 1) gap formation 2) decrease patch size 3) increase isolation 4) increase edge 5) conversion of matrix

17. 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)

18. Concepts • Habitat Availability = accessibility of resources • Habitat Quality = positive relation with fitness (not just density) • Critical Habitat = resources essential to the species….ESA designation….

19. 1st order – innate? Scale Dependence of Habitat Selection 1st Order 2nd Order 3rd Order 4th Order 2nd order –decisions Macrohabitat vs. Microhabitat 3rd &4th order –decisions

23. 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

24. 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

25. Yellow Warbler HSI • for different forest conditions

26. 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

27. Structure Function 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 ? ? ?

28. 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

29. Scale • What’s the big deal? • Seminal pubs • Allen & Starr (1982) – Hierarchy: perspectives for ecological complexity • Delcourt et al. (1983) – Quaternary Science Review 1:153-175 • O’Neill et al. (1986) – A hierarchical concept of ecosystems

30. Long Temporal Scale Short Fine Coarse Spatial Scale 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 Speciation Extinction Species Migrations Secondary Succession Windthrow Fire Treefalls Recruitment

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

32. 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

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

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

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

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

37. Scale in Ecology & Geography • ecological vs. cartographic scale

38. 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

39. 1:24,000 1:200,000

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

41. 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

42. 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 Extent Grain Coarse Fine Scale

43. 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)

44. 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

45. 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

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