Community Ecology: The Florida Everglades

Core Message

• Ecological communities consist of various species that live and interact in a shared area.

• Interactions among species are vital for energy capture, flow, and matter cycling.

• Changes in one component of the community affect others, highlighting the interconnectedness of ecosystems.

• Understanding these interconnections is essential for protecting and restoring damaged ecosystems.

Case Study: An Ecosystem on the Brink

• Wood Stork Decline: From 10,000 nesting pairs in 1975 to ~2,600 in 1978.

• Wood storks were declared endangered in the 1980s.

• Investigating the decline revealed broader issues in the Everglades ecosystem.

What Is an Ecological Community?

• Community ecologists explore interactions among populations in a given area.

Key Terms

• Community Ecology: The study of populations living and interacting within a certain area.

• Habitat: The physical environment where species are found.

• Niche: The unique role a species plays within a community, including resource needs and species interactions.

• Niche Specialist: Species with specific habitat/resource requirements (e.g., wood stork).

• Niche Generalist: Species with broad niches, utilizing diverse resources (e.g., alligator).

Learning from Food Webs

• Food Chains & Food Webs: Represent the flow of energy and matter.

• Food Chain: A linear path of energy transfer starting with producers.

• Food Web: A network of interconnected food chains.

• Producers: Convert solar energy into chemical energy (e.g., plants).

• Consumers: Obtain energy by consuming other organisms (e.g., animals).

Everglades Food Web Examples

• Presence of various species, such as bladderwort, American alligator, wood stork, etc.

Indicator Species

• Indicator Species: Species that signal ecosystem health (e.g., wood storks).

• Wood storks' vulnerabilities provide early warnings for ecosystem issues.

Trophic Levels

• Trophic Levels: Feeding positions in a food chain depicted as a pyramid; energy diminishes at higher levels.

• Consumers categorized based on their feeding (primary, secondary, tertiary).

• Decomposers: Break organic matter down, recycling nutrients back to the ecosystem.

Measuring Species Diversity

• Species Diversity: Quantity and relative abundance of species in a community.

• Species Richness: Total number of different species.

• Species Evenness: Relative abundance of individual species.

• Higher diversity enhances community resilience against environmental changes.

Habitat Fragmentation

• Community Composition: Influenced by habitat structure (core vs. edge habitats).

• Edge Effects: Variations in species diversity at ecotones due to distinct environmental conditions.

Keystone Species

• Keystone Species: Species whose influence on the community is disproportionately high relative to their abundance (e.g., gopher tortoise).

• Their decline can have serious impacts on ecosystem stability.

Species Interactions

Interactions Types

• Mutualism: Both species benefit (+,+).

• Commensalism: One benefits; the other is unaffected (+,0).

• Parasitism: One benefits; the other is harmed (+,-).

• Competition: Both species are harmed (-,-).

• Predation: One benefits; the other is harmed (+,-).

• Resource Partitioning: Different species utilize portions of the same resource to reduce competition.

Restoration Ecology

• Restoration Ecology: Focuses on repairing disturbed ecosystems.

• Indicator species like wood storks serve as benchmarks for successful restoration efforts.

• Importance of preventing ecosystem damage is underscored as restoration is challenging.

Ecological Succession

• Ecological Succession: Evolution of plant and animal communities over time as environmental conditions change.

• Primary Succession: Begins in lifeless areas (bare rock).

• Secondary Succession: Occurs in disturbed ecosystems with existing soil.

Summary

• All aspects of ecological communities are interconnected.

• Difficulties exist in fully restoring species and their interactions once damage has occurred; proactive measures are crucial.

• Loss of keystone species can drastically impact community health.

• Monitoring indicator species like the wood stork provides insight into ecological changes and broader environmental issues.

What Is an Ecological Community?

• An ecological community is made up of different species living and interacting in the same area. Community ecologists study these interactions.

Learning from Food Webs

• Food webs show how energy and matter flow among species. By understanding a community's food web, we can see how different organisms are connected.

Trophic Levels

• Trophic levels are feeding positions in a food chain, like primary, secondary, and tertiary consumers. They are shown as a pyramid because more energy is available at the bottom, supporting fewer organisms as you move up.

Measuring Species Diversity

• Species diversity is measured by counting the number of different species (richness) and how many individuals of each species there are (evenness). More diversity helps communities stay strong against changes.

Core and Edge Habitats

• Core habitats are stable and support many species, while edge habitats are transitional and can host different species. Habitat fragmentation can isolate species and harm their interactions.

Keystone Species

• Keystone species have a major role in their community. If they decline, it can disrupt the entire ecosystem.

Species Interactions

• Species in a community interact in various ways, like mutualism, commensalism, and predation. If these interactions change, it can lead to problems like overpopulation or extinction.

Restoration Ecology

• Restoration ecology aims to fix damaged ecosystems. Challenges include the time it takes to recover and the complexity of species interactions.

Ecological Succession

• Ecological succession is the process by which ecosystems change over time. Understanding this helps in restoring ecosystems by knowing which species will grow as conditions improve.