20 - Community Ecology Shorter

Community Ecology and Biodiversity

  • Focus on understanding the interplay between species and their environment

  • Exam preparation highlights that these topics will not be included in Midterm #2 but are relevant for the final exam

One Health Approach

  • Concept: Emphasizes the interconnectedness of human, animal, and environmental health

    • Objective: Coordinate, communicate, and collaborate across sectors to maximize health outcomes

    • Involves various stakeholders including people, animals, plants, and environmental partners

    • Centers for Disease Control and Prevention (CDC): Plays a key role in orchestrating One Health initiatives regarding zoonotic infections, including COVID-19

COVID-19 and Community Ecology/Biodiversity Links

  • Exploration of how COVID-19 relates to community ecology and biodiversity

    • Contact with wildlife and land use changes contribute to zoonotic diseases

    • Disease spillover and the balance of ecosystems are crucial factors

Human and Animal Health Interconnections

  • SARS-CoV-2: Originated from animal reservoirs, demonstrating the intricate links between animal health and human health

    • Figure 1 shows the One Health approach in the context of COVID-19

Drivers of Zoonotic Diseases

  • Figure 1 Analysis (Jones et al., 2008): Illustrates key drivers of zoonotic diseases from wildlife between 1940 and 2004

    • Land use changes and agricultural practices are significant contributors to disease emergence

  • Understanding these drivers is essential for preventing future zoonotic outbreaks

Years Between Disease Outbreaks

  • Historical data showing the trend of outbreak intervals decreasing over time

    • Examples include various zoonotic viruses such as Marburg, Ebola, and COVID-19

    • Highlighting the increasing frequency of spillover events from bats, urging attention to wildlife management

Impacts of Reduced Human Mobility (COVID-19)

  • Consequences of confinement: Analyze how lockdowns affected biodiversity and ecosystems

    1. Reduced traffic led to less pollution and less wildlife disturbance

    2. Food production drops affecting supply chains

    3. Research and enforcement in protected areas decreased due to restrictions

    4. Shift in wildlife behavior due to quieter environments

    5. Changes in local economies and increased illegal poaching as livelihoods are affected

Economic Effects on Conservation and Biodiversity

  • Various negative effects on conservation efforts due to pandemic-related economic downturns

    • Declines in tourism and funding

    • Increased threats to biodiversity from poaching and land conversion

    • Need for innovative conservation strategies as global biodiversity losses threaten ecosystems

Patterns of Species Richness and Diversity

  • Understanding ecological organization at larger scales, focusing on:

    • Patterns of species richness and diversity metrics

    • How stability and resilience are influenced by species diversity

Community and Ecosystem Ecology Studies

  • Community Ecology: Examines species interactions and factors affecting abundance

    • Ecosystem Ecology: Focus on energy flow and biomass production

    • Key concepts: succession, island biogeography, food webs, energy dynamics

Patterns of Species Richness

  • Geographic variation in species richness, with richness generally increasing from polar regions to tropical areas

  • Factors affecting richness include area size and topographical variation

  • Species-Time Hypothesis: Suggests younger temperate communities have less richness than ancient tropical communities

Hypotheses for Latitudinal Gradients

  1. Species-Time Hypothesis - Time contributes to species richness

  2. Species-Area Hypothesis - Larger areas support more species due to habitat variability

  3. Evolutionary Time and Area - Older and more widespread tree species support more insect diversity

  4. Species-Productivity Hypothesis - Greater biomass production correlates with higher species diversity

Indices and Calculations of Species Diversity

  • Species diversity includes richness and evenness, measured using indices such as the Shannon-Weiner Diversity Index

  • Important for understanding community stability and productivity

Ecological Succession

  • Differentiating between primary and secondary succession and its ecological implications

  • Facilitation Model: Early species modify the environment, aiding others

  • Inhibition and Tolerance models: Different theories explaining how succession can occur

Island Biogeography Theory

  • Examines how species richness on islands is influenced by immigration and extinction rates

  • Predictions: Species richness increases with area size and decreases with distance from the mainland

Food Web Dynamics and Energy Flow

  • Food chains and webs: Illustrate energy transfer between trophic levels

  • Trophic Levels: Primary producers at the base, followed by herbivores and carnivores

  • Ecological Pyramids: Show distributions and energy flow efficiency across trophic levels

Productivity in Ecosystems

  • Gross Primary Productivity (GPP): Total carbon fixed in photosynthesis

  • Net Primary Productivity (NPP): Energy available to consumers after plant respiration

  • Factors influencing productivity include precipitation, temperature, and nutrient availability

Conclusion on Diversity's Role in Ecosystems

  • Higher species diversity tends to increase community resilience and stability, especially during disturbances

  • Elton’s Diversity-Stability Hypothesis: Suggests species-rich communities are more resilient to change

  • Implications of diversity on ecosystem functionality and productivity, emphasizing the need for conservation.