The planet is currently facing an unprecedented loss of biological diversity, prompting scientists to develop strategic methods for safeguarding imperiled species. A fundamental strategy involves identifying geographic regions where the concentration of unique life is highest and the risk of extinction is most severe. This approach, known as conservation geography, focuses limited resources on areas that offer the greatest potential return for protecting global biodiversity. The goal is to pinpoint these critical areas to slow the accelerating rate of species loss.
What Defines a Biodiversity Hotspot
A biodiversity hotspot is a distinct biogeographic region recognized for its high concentration of life and the significant threat it faces from human activity. The concept, first outlined by ecologist Norman Myers, uses two strict quantitative criteria to qualify an area for this designation. These criteria combine an assessment of biological wealth with a measure of threat to identify the most urgent conservation priorities.
To be classified as a hotspot, a region must contain at least 1,500 species of endemic vascular plants, representing more than 0.5% of the world’s total plant species. This high number of unique species indicates an irreplaceable evolutionary heritage. The second criterion requires that the area must have lost 70% or more of its original primary vegetation. This level of habitat destruction signifies an extreme degree of threat to the remaining ecosystems and the species they harbor.
Currently, there are 36 recognized terrestrial biodiversity hotspots that meet these two conditions. While these regions originally covered over 15% of the Earth’s land surface, they have been reduced dramatically due to habitat loss. Today, these 36 zones together occupy only about 2.4% of the planet’s land area. The designation ensures that conservation efforts are directed toward areas that are both biologically unique and highly endangered.
The Approximate Percentage of Threatened Life
These 36 biodiversity hotspots contain a disproportionately high percentage of the world’s species, particularly those facing the threat of extinction. Despite their small combined area, these regions are home to over 50% of the world’s plant species as endemics. This concentration of unique flora provides the foundation for the entire ecosystem’s complexity.
The percentage is similarly high for terrestrial animals, with the hotspots supporting over 40% of all endemic terrestrial vertebrate species, including birds, mammals, reptiles, and amphibians. The vast majority of these endemic species are considered threatened because their entire global population is confined to an area that has already experienced extensive habitat destruction. The focus is on species found only in these regions, making their survival entirely dependent on the fate of the hotspot itself.
The hotspots include nearly 60% of the world’s total plant, bird, mammal, reptile, and amphibian species, a high share of which are endemics. Conserving these 2.4% of the Earth’s surface represents an efficient strategy for protecting a vast majority of the world’s vulnerable organisms. The high degree of endemism coupled with the high rate of habitat loss makes the species within these zones susceptible to endangerment.
The Biological Drivers of Species Endangerment in Hotspots
The concentration of threatened life in these hotspots is primarily driven by a combination of unique biological factors and intense human pressures. The main factor is the high level of endemism, meaning the species have small geographic ranges. This restricted distribution makes endemic species especially vulnerable to localized threats, as a single event can wipe out an entire population or even the species itself.
The primary human-caused driver of decline is habitat loss and fragmentation, often due to agricultural expansion, logging, and infrastructure development. When large habitats are broken into smaller, isolated patches, it creates habitat fragments that cannot support viable long-term populations of many species. Animals requiring large territories, such as certain mammals and migratory birds, are particularly affected by this fragmentation, leading to population declines and increased extinction risk.
Additional pressures include the overexploitation of natural resources, such as unsustainable harvesting or poaching, which directly reduces species numbers. Furthermore, the introduction of invasive alien species poses a significant threat, as non-native organisms can outcompete endemic species for resources, introduce diseases, or act as new predators. These drivers often act synergistically, with climate change exacerbating the effects of habitat fragmentation by pushing species out of their historical ranges and into unsuitable, altered landscapes.
Prioritizing Global Conservation Efforts
The identification of biodiversity hotspots provides a practical framework for maximizing the impact of global conservation funding and policy. Given that the extinction crisis is vast and conservation resources are limited, this “hotspot approach” functions as a triage system. By focusing on these 36 regions, conservation organizations, governments, and donors can direct investments toward the areas where they can save the greatest number of unique and threatened species per unit of effort.
This strategic prioritization guides the allocation of financial resources for establishing protected areas and implementing local conservation projects. The data on species concentration and threat level informs policy decisions, such as where to focus anti-poaching efforts, habitat restoration projects, and community-based conservation initiatives. The approach also encourages international cooperation, as many hotspots cross national boundaries, requiring collaborative efforts for effective long-term protection.