In simple terms, biodiversity is the number and variety of both plants and animals species within a given ecosystem which can range from a small habitat to the entire planet earth.
It is the “sum total of all biotic variation from the level of genes to ecosystems” according to Andy Purvus and Andy Hector in their article entitled “Getting the Measure of Diversity” which appeared in the May 2000 volume of Nature Magazine.
Biodiversity, therefore, encompasses all forms of life on earth. Human destruction of life forms on earth (and thus their diversity) has been on the increase. This has necessitated the need for research to answer questions on how badly this destruction affects the proper functioning of the ecosystems and life on earth which can directly impact on human lives.
The article under review therefore highlights the serious challenges that lie in measuring biodiversity and goes ahead to propose the use of several schemes of measurement such as species numbers, evenness, and difference each of which may not be satisfactory.
Measurement of diversity (though it may be difficult in absolute terms – as pointed out in the article under review) is very important as it gives an indication or points out to the status of a given ecosystem or habitat in terms of its health and life support capabilities.
Information on biodiversity is increasingly being applied in everyday life by both scientists and policymakers, and its importance is now reflected in the increased research activities on environmental issues most of them geared towards reducing the rate of extinction of endangered and other species in the world.
Changes in biodiversity can also lead to ecological outcomes such as increase or decrease of the incidence of herbivory, carnivory, predation, and even in the prevalence of diseases some of which can affect other populations, including plants or animals. Diversity of a single group can also promote the diversity of other associated groups.
However, quantification of biodiversity is often a big challenge because of the complexities involved and the broadness of the subject which calls or more studies in this subject. Researchers have found easier ways to investigate specific area/ facets which in turn point out to new and interesting discoveries.
The article under review has provided enough background information on biodiversity studies carried out so far beginning from the times of Charles Darwin and Alfred Wallace to date. In biodiversity studies, it is recommended that one compares results from several other groups, places and over different time scales to come up with credible information.
It is imperative to select the most appropriate diversity measure, while acknowledging the fact that no single measure can be appropriate in answering all conservation questions.
Challenges have emerged as continued studies on the ecosystem have given insight into biodiversity, allowed inferences on past evolution to the present day to be made, and revealed explosion of species dating back millions of years. Recent discoveries point out to the vast areas that are still unknown to mankind and also predicting that only about 10% of all species on earth have been identified.
The high rate of environmental degradation has also led to habitat loss reaffirming the urgency in dealing with the issue and carrying out more research. Controversies have also emerged regarding studies on some species and many questions remain unanswered.
According to the article under review, some studies have gone further to suggest that biodiversity is always near equilibrium giving an example that when there is an incidence of extinction, then a higher than normal diversification incident is bound to follow.
Temporal patterns in biodiversity have been studied both locally and globally using huge sets of data to support some of these explanatory models. And some studies have even highlighted that there is more biodiversity than numbers of taxa on earth.
Records show that recent rates of species losses are unsustainable and have been increasing and human destruction of ecosystems has been identified as the major cause. Selective destruction is more serious as species are not able to survive or regain their numbers.
Effects of changes in diversity on stability and ecosystem functioning have also shown that principal abiotic and biotic factors such as climate, soil degradation, and disturbances due to population changes and activities of specific organisms can play significant roles in ecosystem degradation.
Some studies have even shown that intact diverse communities in specific ecosystems are generally more stable and function better than those which have lost species.
To conclude, biodiversity studies have shown tremendous improvements over the years as a result of genetic and other molecular tools, etc, and have proved valuable information. However, there is yet a lot to be done.
It is even not absolutely known how many species inhabit earth, and yet there is continuous destruction of ecosystems accompanied by extinctions. Therefore many questions still remain unanswered, which makes it very important to develop the right tools and systems for measuring diversity.