New Paradigms Stable, Simple, Predictable, Equilibrium systems are out Heterogeneity, Transitions, Patches, Landscapes, Disturbance, Nonequilibrium systems are in –Ecological systems are heterogeneous –There are many sorts of patches that are arranged into mosaics and landscapes Disturbance, remnant, regenerated, environmental resource, planted/constructed patches –Boundaries are variously sharp and fuzzy, graded and discrete –Patches, mosaics, and landscapes change temporally and spatially in response to disturbances –We must pay attention to the spatial matrix of ecological processes, understand fluxes of materials and organisms in nature, study the dynamic role of ecotones and edges, know the dynamics of entire landscapes and their parts

Equilibrium to Nonequilibrium Views of communities as integrated superorganisms (Clements 1916) replaced by views of community as group of individuals (Gleason 1917, Whittaker 1965) Views of competition as dominant structuring force replaced by more pluralistic view (density dependent and density independent of many types) View of uniform responses leading to predictable equilibrium replaced by stochastic, variable, individualistic responses disturbed at various spatial and temporal scales leading to mixture of equilibrium and nonequilibrium conditions –Local unpredictability is globally the most predictive aspect of the system (Levin and Paine 1974)

Connections Population is the fundamental unit of conservation ecology, but higher and lower levels have important links to populations Ecosystem Function Community Composition Population Viability Abiotic Inputs Survival, Reproduction, and Dispersal Individual Fitness (modified by age, experience, status) Extinction or Persistence Genetic Variation Breeding Opportunities Predators, Prey, Keystones, Competitors, Symbionts Ecosystem Services Nutrients and Energy

Different Responses to Disturbance (Vogl 1974, White and Harrod 1997) General categories of response –Increasers—present before, increase after –Decreasers—present before, decrease after –Invaders—not present before, present after –Retreaters—present before, not present after –Neutrals—unresponsive to disturbance –Integrators—use multiple patches with variable disturbance history in mosaic (Lynx) Disturbance type specific Assumes species are available at larger scale

Patchiness and Conservation (Wiens 1997) Elements of a landscape mosaic vary in quality determined by many cost-benefit functions that are dynamic rather than fixed Boundary effects are important Matrix affects the boundary (edge) effects Connectivity among patches (or lack of it) is important All these features of a landscape are defined by the structure of the landscape mosaic and by the responses of organisms to that structure

Landscapes as Cost-benefit Contours (Wiens 1997) Peaks with good access to resources Valleys where risks and stresses are great

Our Basic Approach Mapping Predators Interpolating Predator Use of Study Area Relating Annual Productivity or Nest Success to Predator Use

A Landscape of Risk to Nesting Birds in Mora Campground

Change in Productivity from Areas Used Most to Least by Predators

Days to predation for eggs (the darker the color the lower the predation) Days to predation = 8.04 – 8.16 landscape patch density at 5km landscape contrast weighted edge density at 2km – Shannon-Weaver evenness index at 2km (R 2 = 0.27) Lowest Predation where landscape is not patchy, edges are between young forest and old growth, and forest patches are predominantly of a single type Contiguous Young Forest Interface Between Contiguous Old growth And young forest

Correlating Predators and Prey at 3 Scales Landscape Within Patch Forest patch Occurrence of Corvids 0 -2 / count 1 – 1.5 / count 0.25 – 1.5 / count

Species May Vary in Their Exposure to Nest Predators

Importance of Patchiness to Managers Patches are real, pervasive, and increasing Leads to important generalities –Don’t homogenize landscapes—do not do the same thing everywhere (Bunnell 1999) –The matrix matters—management of a patch requires management and planning of surrounding patches (entire landscape; Pickett and Rogers 1997 ) –Larger landscapes are more resilient (persistent native species and communities in the face of local fluctuation)—variety of patch types allows all needs of integrators to be met, provides diversity of conditions, and large area is unlikely to be disturbed in entirely allowing for refuges as needed. (White and Harrod 1997) Requires cooperation and partnerships with many landowners Forces use of adaptive management –Assess expected changes in system –Relate changes to management goals –Adjust as needed –Leads to greater interaction between managers and researchers

More Insights for Management (Wiens 1997) The amount and arrangement of habitat can be important. Knowing which is more important requires an understanding of dispersal. –Inadequate knowledge about dispersal (or invasion) can lead to the inverse of the “field of dreams” phenomenon: build a reserve and no one (or the wrong one) will come Modeling suggests that size and spacing of habitat fragments (reserves) may be less important than their persistence over time

References –Bunnell, F. L What habitat is an island? Pages 1-31 in J. A. Rochelle, L. A. Lehmann, and J. Wisniewski, Eds. Forest fragmentation: wildlife and management implications. Brill, Leiden. –Pickett, S.T.A. and M. L. Cadenasso Landscape ecology:spatial heterogeneity in ecological systems. Science 269: –Kotliar, N. B. and J. A. Wiens Multiple scales of patchiness and patch structure—a hierarchical framework for the study of heterogeneity. Oikos 59: –Vogl, R. J Effects of fire on grasslands. Pages in T.T. Kozlowski and C. E. Ahlgren, eds. Fire and ecosystems. Academic Press. New York. –Whittaker, R.H Dominance and diversity in land plant communities. Science 147: –Gleason, H. A The structure and development of the plant association. Bull. Torrey Botanical Club 43: –Clements, F. E Plant succession: an analysis of the development of vegetation. Publication Number 242. Carnegie Institute, Washington, DC. –Levin, S.A. and R. T. Paine Disturbance, patch formation, and community structure. Proc. National Acad. Sci, USA 71: