Topic1.1 Ecosystem Services
Biodiversity - an important form of Natural Capital
Biodiversity is an important form of natural capital and plays a vital role in the production of ecosystem services through its role in ecosystem processes
Biological diversity or biodiversity includes the variety of different species (species diversity), genetic variability among individuals within each species (genetic diversity), variety of ecosystems (ecological diversity) and functions or processes such as energy flow and matter cycling needed for the survival of species and biological communities (functional diversity).
However, biodiversity is often equated to species diversity (i.e., the number of different species), and other components of biodiversity have received far less attention in scientific literature until recently.
Biodiversity and Ecosystem Processes
A major area of ecological research involving biodiversity conservation is based on looking for possible connections between species diversity and how well ecosystems are able to perform the various ecosystem processes.
As we discussed above biodiversity is an important part of natural capital. However, for the production of ecosystem services it is more important that there are enough of the appropriate species to perform different roles in the system (for example, enough plants to capture energy and create biomass, enough decomposers to breakdown waste products etc.). Therefore in terms of ecosystem services it is more important to conserve species that perform each of the ecosystem processes than it is to conserve any one specific species. For example if we were able to identify the level of biodiversity or specific species required by an ecosystem to function sufficiently to produce the desired ESS we would be able to value and conserve the appropriate level of biodiversity. [Think about some of the problems with this approach to biodiversity conservation, e.g. lack of knowledge, the precautionary principle, preservation of options, the intrinsic value of species].
A NOTE TO ECOLOGY STUDENTS:
You may have come across the concept of the functional role of species and functional diversity. This concept is based on the fact that the functional role of species (i.e. what each species does in the ecosystem) and having enough of the right species to complete each of the roles, is actually more important for the process of ecosystems and provision of ESS than the numbers of species in the ecosystem. To date research in this area has focused on plant communities rather than the full array of biotic organisms.
Loss of Biodiversity
Due primarily to human interventions, particularly land clearing, habitat alteration and the intentional or accidental introduction of exotic species, large numbers of species have become extinct, approximately 1,033 in the last 400 or so years (Lomborg 2001). These numbers are much lower than the estimated numbers thought to have become extinct during the mass extinctions 245 million and 65 million years ago. Half of all marine animals and four legged vertebrates and two thirds of all insects are thought to have been wiped out 245 million years ago.
However, the major difference between mass extinctions in the past and current concerns about species loss is the role humans have in the process.
