Chapter 20: Landscape Eco

Idarado Mine, Colorado 2013

Chapter 20: Landscape Ecology

Edited - Hightower F 17

Individual Levels of Ecological Organization

• Characteristics of Echinacea:

  • Survival, growth, and reproduction in the prairie grasslands of central North America.

Population

• Status Inquiry:

  • Is the population of this species increasing, decreasing, or remaining relatively constant from year to year?

Community

• Species Interactions:

  • How does this species interact with other species of plants and animals in the prairie community?

Ecosystem

• Impact of Rainfall:

  • How do yearly variations in rainfall influence the productivity of plants in this prairie grassland ecosystem?

Landscape

• Influence of Topography and Soil:

  • How do variations in topography and soils across the landscape influence patterns of species composition and diversity in the different prairie communities?

Biome

• Transition Analysis:

  • What features of geology and regional climate determine the transition from forest to prairie grassland ecosystems in North America?

Biosphere

• Role in Global Carbon Cycle:

  • What is the role of the grassland biome in the global carbon cycle?

Landscape and Biomes

• Landscape:

  • An area of land (or water) composed of many different communities and ecosystems.

• Biomes:

  • Geographic regions with similar geological and climatic conditions.

• Biosphere:

  • Thin layer surrounding the Earth that supports all of life.

Terrestrial Landscapes

• Mosaic:

  • A patchwork of different types of land cover.

• Patches:

  • Distinct communities within the landscape.

• Landscape Ecology:

  • The study of the causes behind the formation of patches and boundaries and the effects of these spatial patterns on the landscape.

Habitat Fragmentation

• Example of Habitat Fragmentation:

  • Demonstrates distinct patches in landscapes.

Transition Zones

• Edges of Landscapes:

  • The edges mark the perimeter of each patch.

  • Inherent Edges:

  • Stable and permanent edges.

  • Induced Edges:

  • Subject to successional changes over time.

  • Transition Zones:

  • Offer diverse conditions and habitats.

Borders

• Characteristics of Borders:

  • The edge of one patch meets the edge of another.

• Influence on Patch Climate and Species:

  • Length, width, vertical structure, and the pattern of borders influence the climate and species found at the edge.

Edge Effect

• Definition:

  • Edge communities are often very diverse due to blending elements from adjacent patches, offering unique habitats with easy access to nearby communities.

Importance of Patch Size and Shape

• Species Diversity:

  • Patch size and shape are crucial for species diversity.

  • Examples of the proportion of edge versus interior species are presented.

  • Various examples show how different types and sizes of habitats affect species occurrence probabilities.

Island Biogeography Theory

• Historical Observation:

  • Early explorers noted that larger islands hold more species compared to smaller islands. J.R. Forster noted during Captain Cook’s voyage (1772–75).

• Darlington’s Observation:

  • In the 1960s, he stated that on islands, a tenfold increase in land area leads to a doubling of the number of species.

Equilibrium Theory

• Key Contributors:

  • MacAuthur, Wilson, Simberloff

  • Explains species distribution among oceanic islands focusing on immigration and extinction rates.

• Predictive Model:

  • Predicts an island’s species richness $(S)$ based on size and distance from the mainland.

Species Richness Factors

• Contributors to Richness:

  • Fewer species colonize distant islands.

  • Larger islands have higher immigration rates and lower extinction rates.

Effects of Urban Development on Landscapes

• Habitat Fragmentation:

  • Smaller patches lose diversity faster compared to larger ones.

• Corridors:

  • Can connect patches, facilitating movement of species between habitats.

  • Ensure connectivity for populations.

• Field Studies:

  • Nick M. Haddad studied the influence of corridors on butterfly dispersal.

  • Found that butterfly species were more likely to move between connected patches versus unconnected ones.

Conclusion

• Interpatch Distance:

  • Movement is negatively related to interpatch distance, demonstrating the importance of connectivity for species conservation.

• Environmental Implications:

  • Connectivity and habitat preservation are critical in conservation efforts.

Assigned Questions and Data Interpretation

• Data Interpretation:

  • Refer to specific questions (Q1-Q3) and figures to analyze ecological data.

• Study Questions:

  • Questions are provided for review in chapters 392-393.