Biodiversity is defined as ‘the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems’. This description has been formulated by the Convention on Biological Diversity (CBD 2018) and it is nowadays a universally accepted definition for the term biodiversity.
We humans derive considerable benefits from this diversity. These benefits include ecosystem goods and services such as water purification, pollination, and variety of plants and game for food, remedies and aesthetic and recreational values we obtain from diverse nature. However, our actions have led to a situation where biodiversity is changing and declining rapidly worldwide. This can (and most probably will) have serious and unpredictable effects on nature as well as on the welfare of humankind as this reduction in diversity can have serious effects on economy. For example, it has been estimated that the destruction of US coastal estuaries in 1954–1978 have caused over $200 million losses per year in revenues lost from commercial and sport fisheries (McNeely et al. 1990; National Research Council, US, 1999). This is quite a sum of money.
An old but good example of what can happen to entire ecosystems when their natural diversity has been hampered with comes from the extirpation and resurrection of the sea otter in the Aleutian Islands in 1800-2000s. The initial decline due to extensive hunting, and the later re-emergence of the sea otter populations induced notable changes in their near-shore habitats and in the ecosystem as a whole. The sea otter is the primary predator (and a key species in its habitat) of molluscs and urchins, which, in turn, graze on stands of algae in the coastline. As a result of the loss of sea otters from their habitats, urchins became increasingly more abundant, which then reduced the biomass of the primary producers. As a result, coastal areas without the otters turned slowly into urchin barrens, and the previous ecosystem of kelp bed “forests” disappeared. As the sea otter has been later reintroduced into their previous range, there has been notable improvements in the health of the kelp forests. Overall, the resurrection of the otter populations has afterwards been demonstrated to have an effect on the commercial and recreational value in the area also (Estes & Palmisano 1974, Academies Press 1999). And by the way…if you have a chance, check out the magnificent series Blue Planet II (BBC Natural History Unit). The episode Green Seas gives some insights on these amazing ecosystems with kelp forests, sea otters and urchins. Highly recommended! 🙂
“If the bee disappeared off the face of the earth, man would only have four years left to live.” This is a quote that was supposedly said by the great Albert Einstein himself. Whether or not he actually said this, there is truth behind the statement. Bees and other pollinators are vital for our crop production and agriculture. However, studies have demonstrated that the bee populations have declined worldwide and no consensus on the cause for this has been achieved. Moreover, a recent study from Germany demonstrated that the biomass of flying insects has declined notably – like more than 75 percent over a period of just 27 years (Hallmann et al. 2017)! I don’t know about you, but for me this sounds more than concerning. What are the consequences if this decline continues?
Maintaining and protecting biodiversity is important for the functioning of healthy ecosystems. By protecting biodiversity and nature, we also protect the existence of humankind. This should be enough of a reason for most people to do their part in protecting their surrounding nature, right?
Used references and websites
CBD (2018) Convention on biological diversity. https://www.cbd.int/
Estes & Palmisano (1974) Sea otters: their role in structuring nearshore communities. Science; 185: 1058-1060, DOI: 10.1126/science.185.4156.1058
Hallmann et al. (2017) More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PlosOne, DOI: doi.org/10.1371/journal.pone.0185809
McNeely et al. (1990) Conserving the world’s biological diversity. Washington DC: and Gland Switzerland: World Resources Inst, IUCN, Conservation Intl, WWF, World Bank.
National Research Council (US) (1999) Committee on noneconomic and economic value of biodiversity. perspectives on biodiversity: valuing its role in an ever changing world. Washington (DC): National Academies Press (US); 1999. 3, The Values of Biodiversity. Available from: https://www.ncbi.nlm.nih.gov/books/NBK224412/