8.6 Conserving biodiversity

Cataloging and monitoring biodiversity

Biodiversity is a lovely word because it embraces so many things. But at the same time, it can make the multiplicity of species and ecosystems less visible. We have many approaches to conserving biodiversity without identifying every bacterium, fungus and flower. But to truly understand biodiversity, at some point, that level of knowledge is needed. Biodiversity surveys continue to find new species, especially as genetic tools become less expensive and more widely known. Such surveys are often undertaken by individual researchers and nonprofits, using grants from governments or funding organizations, rarely by agencies, unless on public lands. These can be one-off missions because their goal is discovery.

In contrast to missions of discovery, monitoring is a forever process that must be ongoing if we are to detect changes in biodiversity that signal a need for increased efforts at protection. Monitoring of all biodiversity is perhaps impossible. Researchers estimate the planet houses millions of species, many of which (the smaller and better hidden ones, to be sure) are yet to be discovered. Most national reports on biodiversity begin with a disclaimer about information gaps in even the most urgent kinds of information, such as the status of at-risk species.^[1] Depending on location and level of jurisdiction (national, regional, local), protected areas may have sufficient resources to monitor within their boundaries. But broader-scale monitoring, and especially monitoring on private lands, occurs only irregularly.

At present, approximately 2.1 million species have been formally described, most of which are invertebrates (Fig 1). Of these, the International Union for the Conservation of Nature has assessed status for 172,620, including all terrestrial vertebrates, and found 26% of mammals, 11% of birds, 41% of amphibians, and 21% of reptiles are threatened with extinction.^[2]

Clearly, biodiversity is not secure. How, then, is it being protected?

Laws, treaties, and other agreements to conserve biodiversity 

International protection

Species status assessments and recommendations

The International Union for the Conservation of Nature (IUCN) is an international organization important in determining species status and in recommending approaches for conservation. The IUCN compiles the Red List of Threatened Species, covering, in theory, all species on the planet. They report that they have comprehensive assessments for terrestrial vertebrates, freshwater fishes, reef-building corals, and trees (see above). Assessments are updated periodically, but as might be expected, many groups are incompletely unassessed, and updates are not as frequent as the organization would like.

The IUCN Species Survival Commissions oversees a number of international, species-oriented conservation efforts. Specialist groups are convened for individual species (e.g., Asian elephants) and species groups (e.g., antelope, chameleons, butterflies and moths) to bring together experts from many nations and many jurisdictional levels to share knowledge and training to understand the status of species and the best approaches for their conservation and recovery.

Species protection

As we know, international environmental work is undertaken through treaties. Of these, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, CITES, is the most far-reaching. Almost all nations are signatories to the treaty. CITES operates through a series of species lists that indicate level of threat. Depending on level of threat, CITES regulations limit or ban international trade in the species or in its parts. Countries that have signed CITES agree to work to oversee importation of regulated species and ban importation of protected species. Political issues arise involving which species are listed and at what level of protection. Countries can request to have their species listed, but other nations can impose listings, as well, if they believe a species is not well protected by the nations in which it lives, called the species’ range states. The CITES administration provides training in recognition of protected species, helps nations to cooperate in controlling trade, and generally supports world efforts to ensure that international trade does not harm species or render them extinct. CITES has no enforcement powers. Nations undertake their responsibilities under CITES by incorporating CITES requirements into their national system of laws. In the US, CITES protections are enforced under the Endangered Species Act. CITES does not deal with in-country trade, but only with international trade.

A variety of other, less far-reaching international treaties also protect species. The Convention on Migratory Species of Wild Animals helps protect species ranging from bats to whales that migrate across international boundaries. It provides a framework within which nations can set up coordinated efforts at conservation including setting harvest limits that acknowledge all the potential sites of harvest. Like CITES, it provides protection at more than one level, to ensure appropriate conservation measures. A suite of treaties binds the US, Canada, Mexico, Russia, and Japan to protect migratory birds and sets up coordination of hunting regulations to ensure sustainable harvest of ducks and geese.

Ecosystem protection

The oldest international conservation treaty, and the only one aimed at a single ecosystem type, is Ramsar, the Ramsar Convention on Wetlands, signed in Ramsar, Iran, in 1971, as the world was beginning to understand that perhaps wetlands served some useful functions and should not be eliminated by drainage, plowing, and construction, as if they were a blight upon the landscape. Nations that signed on to Ramsar agreed to nominate one wetland site to the list of Wetlands of International Importance and to support the conservation and “wise use” of wetlands within their borders. The Ramsar administration coordinates training opportunities to improve wetland-protection capacity among nations. The vast majority of nations have signed and ratified the treatment. For many developing nations, their Ramsar wetland was their first nationally protected conservation land.

The Convention on Biodiversity (CBD) was opened for signing in Rio de Janeiro, Brazil, in 1992. The US is the only UN member state that has not ratified the treaty, but it does follow the treaty protocols. Treaty nations agree to create National Biodiversity Strategies to safeguard their biodiversity and to develop Action Plans to implement those strategies. These provide a means for nations to collect and coordinate their biodiversity information so that the national biodiversity picture is detailed and clear, and to coordinate conservation actions across jurisdictions within the nation to ensure effective, efficient conservation. Although the CBD is not specifically an ecosystem conservation measure, by seeking to safeguard biodiversity, generally, it provides an umbrella that includes ecosystem protection.

National protection

Nations differ hugely in the level of protection they afford biodiversity, but as most have signed the Convention on Biodiversity, they have at least created national biodiversity strategies that describe national biodiversity and the risks to it. The existence of such a document gives individuals and organizations outside the government a means of holding their nation accountable for biodiversity conservation, and may open doors for collaboration between government and nongovernmental organizations.

The US Endangered Species Act is widely regarded as the most protective species-level statute in the world. However, as of 2025, efforts are underway to severely undermine its strengths. Other countries have similar laws, but they afford less protection to listed species. Some countries will allow populations of a species to be listed, even if the entire species is not yet at risk; others will not. To date, in the US, habitat of species listed under the Endangered Species Act can be protected, as a means of protecting the species. Because habitat loss is such a pervasive threat to biodiversity, this protection is key to recovering many at-risk species, but is weak or absent from many at-risk species statutes throughout the world. A 2018 review of US state at-risk species laws found that 46 of 50 states had legislation protecting imperiled species, although 2 states only protected the species already listed by the national Endangered Species Act. But the remaining 44 extended state protection to additional species. Only 5 protected habitat.^[3]

Even under the Endangered Species Act, at-risk species are not guaranteed to recover. Funds are not available to support and recover all at-risk species. Some are essentially put on hold due to lack of resources. The law requires that their status be monitored and that, if they show signs of sudden decline, they are to be protected. But as we have seen earlier, such monitoring is itself expensive and imperfect. Even when species are listed, they may still become extinct if managers and researchers are unable to reverse population declines. Genetic problems, novel diseases, irreversible habitat loss, climate change, and other stresses may not be amenable to correction, despite the best efforts of experts.

Efforts to protect listed species are often met with demands that conservation groups and agencies should be willing to compromise in their requirements. However, most populations and species only become listed when their status has become dire and there is little room left for compromise if they are to be kept from extinction. Listing these species earlier, when they are declining but not yet approaching risk of extinction, would increase the number of listed species dramatically, requiring more conservation planning, imposing more work on municipalities and industries that might harm the species in question, and perhaps reducing public support for biodiversity conservation. However, avoiding the transparency of honest reporting on the status of so many species is often not working well, either.

Protecting biodiversity by protecting land – protected areas

Protected areas occur at many levels of jurisdiction and in all countries. The degree of protection also varies. The IUCN describes 7 levels of protection for protected areas, ranging from areas that can only be accessed for scientific research to areas in which sustainable use of natural resources is permitted. In the US, national parks typically permit only recreational and scientific use, and conservation of cultural resources – these lands are designed to preserve and protect their resources for future generations. In other nations, villages may exist within parks and may use the resources of the park. Elsewhere, inhabitants of villages outside the park may have permission to enter to secure fodder for livestock, building materials, etc. In the UK, sustainable plantation forestry may occur in national parks, and private land is contained within many, where grazing of livestock is a regular use of the land. Conservation grazing is often used to manage habitats.

Measures that exclude local and indigenous human populations from their lands in the name of creating protected areas have sometimes given national parks and other protected areas a bad name, in the same way that dam construction that requires the relocation of local and indigenous residents has a bad name. In addition to being unjust, disenfranchising people who are knowledgeable about species and ecosystems of an area risks losing valuable historical and current information that may be needed for informed management of the land and its species.^[4]

The ability of protected areas to conserve biodiversity is related to the characteristics of the protected areas. Experts have developed recommendations for designing protected areas and systems of protected areas and additional recommendations are designed to maximize protection against impacts of climate change.^[5]

Big blocks are best. Large areas have large core areas where the impacts of surrounding land uses are muted. For many species, large areas can protect one or more viable populations that can persist in the face of population reductions due to climate change and other disturbances. Disturbances such as fire or flood or storms are less likely to affect all of a large area, leaving intact areas to shelter plants and animals and to provide colonizers to reestablish populations in affected areas, if necessary.

Topographic variation provides diverse microclimates and habitats. Protected areas that include mountains or whatever topographic variation is available will have lower warmer areas and higher cooler areas, with attendant variation in soil moisture and precipitation. The variety of conditions supports a variety of species, and the elevational gradient provides some opportunity for mobile species to find preferred temperatures and moisture levels in a relatively short distance compared to shifting poleward. Poleward facing slopes (north-facing in the Northern Hemisphere, south-facing in the Southern Hemisphere) receive less sunlight during the day than equator-facing slopes, and different soil types provide different levels of drainage, suiting a variety of plants and the food webs they support.

Connectivity and permeability provide passage as species seek appropriate climates and resources. Modern landscapes present a series of obstacles and barriers to organisms moving through them – highways, cities, large agricultural regions, etc. For many species, such barriers render landscapes impermeable – the probability of surviving passage through them is very low, and the landscapes become killing fields. Corridors of natural habitat – for example, streams with intact streamside habitat – can improve connectivity among natural areas. Protected areas that include such corridors can facilitate dispersal of young animals, seasonal migrations, and movement to adjust to climate change or other disturbance. For more mobile species, stepping stones may suffice – islands of habitat close enough together to provide resting spots, foraging spots, etc. But for less mobile species and species at higher risk in highly modified habitats, intact corridors may be necessary.

Certain settings create local refuges from climate change. Within any landscape, some locations will be cooler and moister than others – these are climate-change refugia.^[6] Poleward-facing ravines and canyons are naturally cooler than equator-facing depressions. Spring-fed rivers may have cooler waters than rivers that are fed only by rainfall and runoff. Mountain areas downslope of glaciers and snowpack are cooler than areas without such natural refrigeration. Areas shaded by forest and cooled by evapotranspiration from the vegetation are cooler than more exposed ecosystems. Land along large bodies of water will have more moderate climates because water warms slowly and cools slowly. These areas will not maintain constant conditions under climate change – everything is getting warmer. But they will remain cooler than nearby areas, and may give species longer to adjust to changing conditions.

Species-specific protection

The guidelines above are helpful for identifying areas that can protect biodiversity broadly. But areas that are broadly protective may still fail to meet the needs of some species, particularly endemic species that inhabit only small areas or only certain very specific habitat types. Endemic species may not need large areas, only areas that preserve their particular needs. However, it is important to keep in mind that, under climate change, these areas may no longer meet the needs of the species for which they were created, and flexibility in protected area system design will be needed to accommodate change needs under changing conditions.

Protected areas may be hard to situate in high-quality agricultural areas or in dense urban areas, simply because the land is not available. But these areas have (or once had) their own biodiversity, which may be at particularly high risk. In the US, schools in urban areas have begun to provide pollinator gardens to support breeding and provide habitat connectivity for pollinator species, including monarch butterflies. In Europe and elsewhere, climate-smart urban planning is increasingly restoring wetlands and building parks in areas that flood easily, to collect flood waters in areas that will not be harmed by being inundated and reduce flood risk in other, more built environments.

In some instances, protected areas are created with a strong emphasis on one or a few species – usually these are smaller areas for endemic species. Local communities and indigenous people may protect culturally significant species and ensure sustainable harvest of species important to subsistence within lands they control. Climate change is complicating such efforts, as species’ ranges shift. Typically, it’s not feasible to have a movable protected area. Similarly, local communities and indigenous people likely cannot track across the landscape the species with which they have special relationships.

Captive propagation

As a means of protecting biodiversity, captive propagation is the practice of taking individuals of an at-risk species into captivity in order to safeguard genetic diversity, to breed individuals to supplement faltering wild populations, or to take entire species into protective custody if their populations are extremely low. Captive propagation is expensive, time-consuming, and intensive. It requires deep knowledge of species biology and ecology which is often lacking, with the result that efforts may not initially be particularly successful. Some species need breeding or other conditions that cannot be met in captivity. When it works, captive propagation can save species. But the capacity of existing facilities can support only a handful of species in this way. Triage to identify the most needy species and the species for which efforts are most likely to be successful are constantly ongoing, and failures are heartbreaking.

One limitation of captive propagation is that it cannot fix whatever was broken in the species’ environment that led to its extreme decline. One aspect of triage is often whether there will be a place to release captive-bred and reared individuals – a place to reestablish the species. If conflict, habitat loss, or changing conditions such as climate change have eliminated appropriate release areas, then captive propagation can only maintain a semblance of the species in protective custody. Prolonged captivity leads to changes in genetics and behavior that can rapidly reduce the chances for successful release of individuals and that can permanently change the nature of the species. Such changes will occur quickly for some species and much slower for others, but unless donors come forward to fund permanent custody, facilities will not be able to afford to support species in captivity without a clear path to eventual release.

With the advent of biotechnology, some groups are seeking to resurrect extinct species using recovered DNA and by intensively breeding existing related species for the characteristics of the lost species. Such efforts can attract considerable attention, but they can detract from efforts to conserve existing biodiversity. If (or when) such efforts are successful, the vanished species will compete with existing biodiversity for space and resources which are already in short supply.

Knowledge Check

Take a moment to complete the short quiz below to assess your understanding of this section. Read each question carefully and refer to the section content as needed. This quiz is not graded – it’s simply an opportunity for you to reflect on what you’ve learned and reinforce key concepts.