Biodiversity Research & Science Reference

Biodiversity refers to the variety of life on Earth at every level — genetic variation within species, the number and evenness of species in a community, and the range of ecosystems across a landscape. It matters because biological diversity underpins ecosystem functioning: nutrient cycling, pollination, water purification, climate regulation, and food production all depend on a rich variety of interacting species. The IPBES 2019 Global Assessment estimated that nature provides services worth USD 125 trillion per year to the global economy — all of which rely on biodiversity.

Scientists recognise three primary types: genetic diversity (variation in DNA among individuals within a species), species diversity (the variety and relative abundance of species in a community, measured by indices such as Shannon-Wiener H'), and ecosystem diversity (the range of habitats, biotic communities, and ecological processes in a region). Each level is interconnected — low genetic diversity often precedes local species extinction, which in turn erodes ecosystem diversity.

Habitat loss and degradation is consistently identified as the single largest driver of biodiversity decline, affecting more than 85% of all species listed as threatened on the IUCN Red List. Habitat loss is most acute in tropical forests and freshwater systems, where agricultural expansion, urban sprawl, and infrastructure development convert or fragment native habitats faster than species can adapt or relocate. Climate change is an accelerating second threat, particularly for polar, alpine, and marine species.

Conservation International currently recognises 36 biodiversity hotspots worldwide. A region qualifies under two strict criteria: it must contain at least 1,500 endemic vascular plant species (species found nowhere else), and it must have already lost at least 70% of its original primary vegetation. Together, these 36 regions cover roughly 2.5% of Earth's land surface yet support more than 43% of all bird, mammal, reptile, and amphibian species as endemics, making them conservation priorities of global importance.

Population ecology provides the quantitative framework for understanding how many individuals of a species exist, where they live, and how that number is likely to change. Its applications include fisheries management (setting sustainable catch limits), wildlife conservation (estimating minimum viable population sizes), invasive species control (predicting spread rates), disease ecology (modelling epidemic dynamics), and agricultural pest management. Population viability analysis (PVA), a core tool in conservation biology, uses population ecology models to estimate the probability of a species' extinction within a given time horizon.