What is Conservation Biology?
Conservation biology is a recent scientific discipline that was initiated in the 1980s in response to the loss of biodiversity. It is devoted to study the causes of biodiversity loss at all levels (genetic, individual, ecosystem) and how to minimize this loss. This integrates contributions from various other disciplines, such as ecology, genetics, geography, political science, sociology, anthropology and so on.
Principles of conservation biology:
- The evolution is the only mechanism capable of explaining biodiversity patterns, so that the answers to the conservation issues must be generated within the evolutionary framework.
- Ecological processes are dynamic and not kept in balance (at least not indefinitely), and often functioning under the control of other variable external process.
- Humans are part of ecological systems, so human activities should be considered while planning biological conservation.
Why does biodiversity decline?
There are several factors that are causing many populations and species to decline, however in the majority we are involved humans:
- Habitat loss: when cities grow, or forests are felled to put crops
- Climate change
- Introduction of predator species
- Human Overexploitation
Conservation biology develops within two paradigms – the paradigm of small populations and the paradigm of declining populations.
Paradigms of small populations
This paradigm states that small populations are subject to an inherent risk of extinction, resulting primarily from an increase in exposure to environmental and demographic anomalies and loss of genetic variability.
Paradigms of declining populations
It deals with the processes by which the risk of extinction of a population increases for reasons unrelated to them, and how to alleviate such a decline.
It has also been called ‘extinction vortex’in which inbreeding depression, demographic and environmental irregularities and genetic drift combine to accelerate the decline in population. The rationale is that these factors lead to a loss of genetic variability and consequently the decrease in the biological effectiveness of individuals and an increase in mortality.
Main Factors of Extinction
According to conservation biology there are four main factors leading to extinction, which are:
Over-exploitation is killing at a rate that is above the maximum sustainable yield. The most susceptible species are those with low intrinsic growth rates, for example, large mammals such as whales, elephants and rhinos. These species become even more vulnerable if they are valuable as food or merchandise.
The loss and fragmentation of habitat
Sometimes the habitat is removed, as in the case of a drained water environment or a forest clearing. More commonly the habitat is fragmented, when part of it is destroyed to build roads, buildings, or make plantations. Habitat fragmentation can be analyzed by considering the dynamics of subdivided populations in small patches. In general there is a close relationship between body size of the animals and the area required for their survival and reproduction; larger animals need more habitat area.
The introduction of invasive species
The third agent of decline is the introduction of exotic species, whether intentionally or not. This can wipe out native species through competition, predation or habitat destruction. The islands of Hawaii are famous throughout the world for the extraordinary number of alien species. But they are also responsible for the elimination of many native plants and birds.
This largely involves secondary extinctions – the extinction of a species due to the extinction of other species on which it depends. The clearest examples of such extinction chains involve predators who disappear when their prey becomes extinct.
What can be done to prevent extinction?
In general there are two ways of facing the problem of extinction:
- In-situ conservation: to protect the habitats and ecosystems where endangered species live, through for example a national park (eg: Chinchillas National Park) or private reserve (eg Pumalin)
- Ex situ conservation: it is considered a last resort when the survival of a species in the wild is no longer safe. Some individuals are taken to a zoo or laboratory to have an “artificial” population in the hope that someday they may be released into their natural habitat (eg, panda bears)
IUCN (International Union for the Conservation of Nature) is one of the main international conservation organizations that have developed a Red List of threatened species which classifies species in different categories according to their extinction risk. This classification helps to focus efforts on species that are at a greater threat level.