What is Biodiversity?

Biology is the study of all living organisms (plants, animals, microorganisms) and how they interact with each other and their environment. It examines the structure, classification, function, growth, origin, evolution, and distribution of all living things.

Biodiversity, abbreviated from the terms 'biological' and 'diversity', encompasses the variety of lifeforms found at all scales of biological organisation, ranging from genes to species to ecosystems. The greatest biodiversity is found in the tropical regions of the world, particularly among tropical rainforests and coral reefs. Biodiversity is increased by genetic change and evolutionary processes and reduced by habitat destruction, population decline and extinction. There is a growing recognition that the level of biodiversity is an important factor in influencing the resilience of ecosystems to disturbance.

Biodiversity is a complex term that includes not only the variety of different animals (species diversity) but also the difference between animals of the same species (genetic diversity) and between ecosystems (ecosystem diversity).

Genetic Diversity is the diversity of genetic characteristics (expressed or recessive) within a species (i.e. between individuals and populations of the same species). This component of biodiversity is important because it allows populations to adapt to environmental changes through the survival and reproduction of individuals within a population that have particular genetic characteristics that enable them to withstand these changes. The maintenance of high genetic diversity within populations is therefore a conservation and management priority as this provides the greatest capacity for any population to adapt to a broad range of environmental changes. Conversely, failure to maintain genetic diversity limits the capacity for a population to adapt, making it vulnerable to even small changes in the environment and increasing the likelihood of extinction.

Species Diversity is simply the number and relative abundance of species found in a given biological organisation (population, ecosystem, Earth). Species are the basic units of biological classification and hence, this is the measure most commonly associated with the term 'biodiversity'. Worldwide, about 1.75 million different species have been identified. However, many environments and groups of organisms are not well studied and estimates of species numbers range from 3 to 100 million. Diversity in species is important for economic, biological, social and cultural reasons. Major threats to species diversity are loss of habitat and fragmentation, over exploitations (fishing, hunting, extraction), pollution, the introduction of invasive species (e.g Asian Green Mussels) and global climate change. In order to conserve species diversity, natural resource management and habitat protection are vital.

Ecosystem Diversity can be defined as the variety of different habitats, communities and ecological processes. A biological community is defined by the species that occupy a particular area and the interactions between those species. A biological community together with its associated physical environment is termed an ecosystem.

Partly due to its complexity, biodiversity can be extremely difficult to measure. However, there are a few key indicators of biodiversity that we can accurately and efficiently monitor. For coral reefs these indicators include: seafloor diversity, seagrass, mangroves, seabirds, species of conservation concern and species richness and community structure of hard corals on the GBR.