What is biodiversity?
What is biodiversity?
• “Biological diversity is the wealth of life on earth, the millions of plants, animals, and
microorganisms, the genes they contain, and the intricate ecosystems they help to
build into the living environment.” (WWF 1989)
Levels of biodiversity
• Genetic diversity: differences in genes
• Species diversity: differences within and between populations, AND between different
species, taxa diversity
• Ecosystem diversity: different habitats, biological communities, and ecosystem
processes
Structure versus and function
• The term biodiversity incorporates not only structure (e.g., species) but also function
(e.g., ecological processes)
Hydrogeomorphic (HGM) classification of wetlands
Species diversity
• Richness = # of species in a given area/community
Species diversity
• Evenness = equity of numbers of individuals of each species in a given area
– Shannon Diversity Index (H)
– Simpson Index (D)
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•
Often use more than one index
Difficult to measure in practice
Shannon diversity index (S)
• Insert table here
Not all species are equal in conservation
Endemism
• Endemic: a species found in a particular region and nowhere else
• Levels of endemism high for areas that have been isolated for long periods of time,
especially islands
18 regions of high endemism
Biodiversity and spatial scales
• -richness - number of species in a small homogeneous area
• -richness - rate of change in species composition across habitats
– Species turnover
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-richness - rate of change across larger landscape gradients
– Community overlap
-diversity
• Number of species coexisting in a uniform habitat of specified size
• High -diversity results from “packing” of species into habitats and high habitat
specialization
-diversity of Caribbean birds
• High -diversity habitats often have lower average population abundances
-diversity
• Rate of change in species composition along environmental gradients within the same
geographical region
• Usually measured in terms of species turnover, the number of new species appearing
along the gradient
• High -diversity results from high habitat specificity
-diversity in Mediterranean birds
• For three different regions with Mediterranean climate, Africa shows the highest
species turnover rate (number of species replaced per unit habitat), and hence, the
highest -diversity.
-diversity
• The rate at which additional species are encountered over a large geographical area
• Usually measured in terms of community overlap, with habitats with small community
overlap having high -diversity
-diversity in Australian birds
• Of three widely distributed habitats, heath has the highest bird -diversity.
Different conservation goals?
• “Maximizing, enhancing or increasing” biodiversity
• “Restoring” biodiversity
• “Protecting” biodiversity
• “Preserving” biodiversity
• Solution is to clearly identify conservation goals
Biodiversity enhancement in Clear Lake
Ecological integrity
• Strong focus on functions
• “If you build it, they will come.”
Sustainability
• Long term use of a resource without diminishing it