Earth is home to approximately 9 million species of plants, animals and fungi. Together they form complex ecosystems that undergird the stability of the natural world, and ultimately help to sustain human life. The study of ecosystem functioning is crucial to understanding how continuing loss of biodiversity could affect humanity’s future.
A 2012 metastudy published in the journal Nature, “Biodiversity Loss and Its Impact on Humanity,” reviewed more than 1,700 papers — more than 20 years of research — that examined the loss of biodiversity within ecosystems and the implications for human civilization.
The study’s highlights include:
There is “unequivocal evidence” that biodiversity loss reduces the efficiency with which ecosystems capture resources, produce biomass and decompose and recycle biologically essential nutrients.
On balance, the data show that biodiversity helps with certain “provisions” in many ecosystems. Examples include “(1) intraspecific genetic diversity increases the yield of commercial crops; (2) tree species diversity enhances production of wood in plantations; (3) plant species diversity in grasslands enhances the production of fodder; and (4) increasing diversity of fish is associated with greater stability of fisheries yields.”
Biodiversity helps regulate the functioning of ecosystems, including: “(1) increasing plant biodiversity increases resistance to invasion by exotic plants; (2) plant pathogens, such as fungal and viral infections, are less prevalent in more diverse plant communities; (3) plant species diversity increases above-ground carbon sequestration through enhanced biomass production … and (4) nutrient mineralization and soil organic matter increase with plant richness.”
“[The] loss of higher consumers can cascade through a food web to influence plant biomass. Loss of one or a few top predator species can reduce plant biomass by at least as much as does the transformation of a diverse plant assemblage into a species monoculture.”
The authors suggest that additional research into the value of biodiversity is needed: “Although there are good estimates of society’s willingness to pay for a number of non-marketed ecosystem services, we still know little about the marginal value of biodiversity (that is, value associated with changes in the variation of genes, species and functional traits) in the production of those services.”
Related research: A 2009 paper published in the Annual Review of Resource Economics, “The Economics of Endangered Species,” provides an overview of contemporary thinking and modelling with respect to biodiversity.