Community Ecology Definition: an interacting group of populations in a defined space

Ecological Hierarchical Classification Biosphere Biome Ecosystem Community Population Individual Gene

Underlying Assumptions 1. Communities frequently recur in different areas with similar abiotic and temporal conditions. Where one group of species is found, others are likely to occur in the same region.   However, 2. The community itself is hard to define. Differences among associations are inevitable and mixing at the edge certain.

Calystegia spithamaea (L.) Pursh; endangered in Massachusetts Why Study Communities? Calystegia spithamaea (L.) Pursh; endangered in Massachusetts Rare species are hard to find: knowing the types of habitat in which they live is the best place to start. We will be using a Geographic Information System approach to the study: map the habitats in the field and overlay with range/observation data.   The study of communities is critical to the study of wildlife and conservation biology as these are frequently the management units Massachusetts Natural Heritage and Endangered Species Program       “Last of the Least; Best of the Rest”

“Last of the Least; Best of the Rest” MNHESP’s Approach “Last of the Least; Best of the Rest”

Theories of Community: Is the concept of a community defensible? Field verification of similar populations in areas characterized by similar abiotic and temporal factors Theories of Community (IA vs. co-evolutionary)

Review of Critical Evolutionary Concepts Specialist v. Generalist – introduce question Adaptations and Evolutionary Trade-offs Most important selective pressures in understanding community ecology Moisture Shade Disturbance

Population Responses to Varying Conditions Range of Tolerance Changes in abundance

Vegetation Indices and Community Metrics Presence Absence Density/Relative Density Dominance/Relative Dominance

Definition of a community is difficult Patterns of Distribution Biotic Abiotic Temporal Critical importance of sampling

Communities of Groton

Classification Systems Based on structure and composition of the vegetation Soils, geology, disturbance and moisture serve to refine and validate the classification Multiple systems Hierarchical System of Classification

Frequency of Selective Pressures Consistent or episodic

Succession and Adaptations to Disturbance

Aquatic Succession US National Park Service

Adaptations to Moisture

Other Selective Pressures Herbivory Pollination and other Mutualisms Competition

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Vernal Pools - Critical