By Adyasha Padhi, Biochemistry and Molecular Biology and Sociocultural Anthropology ’25

Humanity has impacted our planet’s biodiversity in extensive ways, both deliberately and accidentally. According to the World Wildlife Fund, there has been an average of a 69% decline in worldwide biodiversity since 1970 [1]. However, some geographical areas and ecosystems are disproportionally affected. Biodiversity in the Caribbean and Latin America has dropped 94% and their freshwater populations are experiencing an 83% decrease in biodiversity [1]. The four most significant drivers of biodiversity loss are land use change (30%), overexploitation (20%), climate change (14%), and invasive species (11%), all of which are associated with human activity [2]. Overall, the impact of all biodiversity drivers is increasing and so is the rate of biodiversity decline. 

One of the major ways that we attempt to repair the damage that we have done to our planet is through wildlife conservation efforts. However, examining conservation efforts reveals startling trends in which species receive focused protection, policy efforts, research, and funding. These inequities call into question the efficacy of many widespread conservation programs. 

What is biodiversity and why is it important: 

Biodiversity refers to the variety of life on Earth at all levels, from genetic diversity in a population to organism diversity within an ecosystem. This encompasses both the sum of total life forms across an area and the range of differences between those forms. While the biodiversity of some organisms is widely valued instinctively, some are not, such as microbiota, insects, and plants. Nevertheless, these undervalued organisms perform functions that are essential to maintaining stable ecosystems. Biodiversity supports healthy life on Earth– a lack of diversity at any level of life can lead to ecosystem collapse. This is because greater biodiversity in individuals, species, and ecosystems leads to greater ecosystem stability, and the populations within them are more likely to be able to withstand a range of disturbances, such as disease outbreaks and climate change. 

Biodiversity is usually explored at three levels: genetic, species, and ecosystem. For the purposes of conservation, species diversity is most often the focus. While genetic and ecosystem diversity are both extremely important, species diversity can offer insight into the health of both of these while being more manageable in scope. If species diversity is low in an ecosystem, that has implications on both the genetic diversity of the species that make up that ecosystem and that ecosystem as a whole in relation to other ecosystems. One way to measure species biodiversity is with a biodiversity index. A simple biodiversity index is calculated by dividing species richness (the number of species in an area) by species evenness (the total number of individuals in the same area) [7]. 

By using metrics such as the biodiversity index, researchers have found that biodiversity has been decreasing at an unprecedented rate [3]. Furthermore, certain areas around the equator known as biodiversity hotspots are experiencing biodiversity loss at even higher rates than other areas [3]. Human activity is contributing to all of the major driving factors for biodiversity decline, such as climate change, the effects of which are accelerated by the continued loss of biodiversity in ecosystems worldwide, creating a cycle of damage and loss. 

Conservation: Who gets chosen, and why? 

One way to mitigate the negative impacts humans have had on the planet is through conservation efforts, or protecting species and their habitats to restore populations and ecosystems. Conservation efforts typically fall into one of two categories: preventing further destructive forces from acting on ecosystems, such as stopping deforestation or stimulating populations through breeding and protection, in order to revitalize injured populations. These efforts are typically in-situ (conservation of habitats, species, and ecosystems where they naturally occur) or ex-situ (conservation of elements of biodiversity out of the context of their natural habitats, such as zoos, seed banks, and botanical gardens). 

Financial, land, and labor resources are limited, so the conservation of certain areas or species is forced to be prioritized over others. A common approach for selecting these priority areas for conservation is to focus on hotspots of diversity. These “hotspots” are regions of high conservation priority due to their high levels of richness in species, rates of endemism (uniqueness to that certain region), and threats to survival. Currently, there are 36 designated hotspots worldwide. These biogeographic regions are most commonly found around the equator and hotspots have lost around 85% of their habitat area [3]. 

Another metric used to determine the status of certain species is the International Union for Conservation of Nature (IUCN) Red List. The IUCN is an international organization for nature conservation and the sustainable use of natural resources. It is most well known for its Red List, which is regarded as the world’s most comprehensive inventory of the global conservation status of biological species. They report that they have assessed 42,100 species at risk of extinction, but a 2019 United Nations report estimates that of all existing species, a million are at risk of extinction in total. This disparity reflects how few existing species have been assessed by the IUCN. Prioritizing certain species and ecosystems is needed due to the limited resources that conservation organizations have, and the increasingly complex social, cultural, and political factors that further inhibit conservation efforts. 

Conservation efforts are often focused on a single species, and these species are often categorized into three categories that define their relation to their ecosystem: keystone, indicator, or flagship, with overlap between the categories. Keystone species play an essential role in the structure, function, or productivity of a habitat or ecosystem and the disappearance or diminishment of one of these species may lead to significant ecosystem change and dysfunction. One famous example of a keystone species is the Grey wolf in Yellowstone. As predators that regulate prey populations, the wolves enabled many species of plants and animals to flourish. After their disappearance in 1926, their reintroduction into Yellowstone in 1995 was a conservation effort that had highly successful effects on the entire food structure that defines the Northern Rockies ecosystem [12]. An example of a keystone species acting as ecosystem engineers are beavers, who regulate tree growth in the river ecosystems and also divert rivers with their dams, creating wetlands and ponds which support a wide range of organisms, which would not be able to survive in the more aggressive environment of a river. Despite their small size, bees are also a keystone species due to their integral role in pollination [13]. Plants too can be keystone species, such as Mangrove trees, which play an essential role in many coastal ecosystems by protecting coastlines from the impacts of waves and reducing erosion, while also providing a safe haven for small marine organisms to survive, which in turn has wider impacts throughout the food web.

Indicator species are species or groups of species chosen as an indicator or proxy for the state of an ecosystem. An example of this is crayfish as indicators of freshwater quality and peregrine falcons as an indicator of pesticide loads. Flagship species are selected to act as a symbol for a defined habitat or environmental cause due to their “charismatic” nature, especially in Western cultures, which is often where the funding for many conservation campaigns comes from [5]. These flagship species are typically large mammals that may or may not be keystone species and are not necessarily good indicators of biological processes in their ecosystems or of the conversation status of their ecosystem. Examples include tigers, kangaroos, elephants, and pandas [11]. 

Flagship species campaigns centered around these “charismatic” animals have been found to be more effective than other types of conservation campaigns [4]. Researchers have found that public donors were more likely to donate to a flagship charismatic species, regardless of the endangered status of the species [4]. Features of charismatic species include colorful coats or forward-facing eyes [6] because these appeal most to the broadest audience and these species are often featured in media & spaces where the public can interact with them, such as in movies or in zoos. The Similar Principle Theory finds that humans have a preference for animal species that are more similar to them. This is in both physical characteristics, such as forward-facing eyes and expressive faces, and social characteristics. As such, some researchers posit that the chances of survival for many species depend as much on human preferences as on existing biotic and abiotic factors, if not more [4]. 

Paradoxically, many of the animals regarded as the most charismatic are at high risk of imminent extinction, which some researchers attribute to the biased perception of the abundance of these animals since they are commonly overrepresented in our culture, such as pandas, tigers, and lions being common in our zoos, media, and educational material [6]. While some have called out this focus on animal charisma as being too narrow and excluding many species, charismatic flagship species conservation campaigns have been more successful in securing funding than campaigns that do not feature a flagship species [4]. However the status of many other species which share their habitat – or are vulnerable to the same threats – may also be improved by campaigns that target charismatic species. This is due in part to the large habitats that charismatic animals tend to live in due to their size and their position often being higher up on the food chain. Ultimately, researchers are calling for the shift away from campaigns centered around charismatic species and towards ones that focus more on the health of the ecosystem as a whole, even if this is less visible [6]. 

Conclusion

Biodiversity on all levels is an essential aspect of global health as it supports ecosystem health and stability via pollination, water purification, climate regulation, seed dispersal, agricultural pest control, and nutrient cycling. As such, all organisms, biotic, and abiotic factors that make up an ecosystem are extremely important in their own ways, and this means that even organisms that we don’t intrinsically value or find charismatic are important. Protecting all species is integral to protecting the health of the world as a whole and combating climate change. 

References

[1] “69% average decline in wildlife populations since 1970, says new WWF report,” World Wildlife Fund, 2022. https://www.worldwildlife.org/press-releases/69-average-decline-in-wildlife-populations-since-1970-says-new-wwf-report

[2] The Royal Society, “What is the human impact on biodiversity? | Royal Society,” royalsociety.org, 2022. https://royalsociety.org/topics-policy/projects/biodiversity/human-impact-on-biodiversity

[3]N. Myers, R. A. Mittermeier, C. G. Mittermeier, G. A. B. da Fonseca, and J. Kent, “Biodiversity hotspots for conservation priorities,” Nature, vol. 403, no. 6772, pp. 853–858, Feb. 2000, doi: https://doi.org/10.1038/35002501.

[4]A. Colléony, S. Clayton, D. Couvet, M. Saint Jalme, and A.-C. Prévot, “Human preferences for species conservation: Animal charisma trumps endangered status,” Biological Conservation, vol. 206, pp. 263–269, Feb. 2017, doi: https://doi.org/10.1016/j.biocon.2016.11.035.

[5]C. Mazzoldi et al., “From sea monsters to charismatic megafauna: Changes in perception and use of large marine animals,” PLOS ONE, vol. 14, no. 12, p. e0226810, Dec. 2019, doi: https://doi.org/10.1371/journal.pone.0226810.

[6]F. Courchamp, I. Jaric, C. Albert, Y. Meinard, W. J. Ripple, and G. Chapron, “The paradoxical extinction of the most charismatic animals,” PLOS Biology, vol. 16, no. 4, p. e2003997, Apr. 2018, doi: https://doi.org/10.1371/journal.pbio.2003997.

[7]“Guide on biodiversity measurement approaches (2nd edition),” Finance for Biodiversity Pledge. 2022. https://www.financeforbiodiversity.org/publications/guide-on-biodiversity-measurement-approaches/

[8]K. Whiting, “6 charts that show the state of biodiversity and nature loss – and how we can go nature positive,” World Economic Forum, Oct. 17, 2022. https://www.weforum.org/agenda/2022/10/nature-loss-biodiversity-wwf/

[9]J. H. Lawton and K. J. Gaston, “Indicator Species,” ScienceDirect, Jan. 01, 2001. https://reader.elsevier.com/reader/sd/pii/B9780123847195000745?token=68CA7F85D7A3FD42B151DC0DDD681D1E44822EC03A422ABFA252CF19E4E9E70F88BD7C79CB9E562C1AD10E92193926FA&originRegion=us-east-1&originCreation=20230411171712 

[10]M. C. Horner-Devine, K. M. Carney, and B. J. M. Bohannan, “An ecological perspective on bacterial biodiversity,” Proceedings of the Royal Society of London. Series B: Biological Sciences, vol. 271, no. 1535, pp. 113–122, Jan. 2004, doi: https://doi.org/10.1098/rspb.2003.2549.

[11]J. Qian and H. Zhuang, “Selecting flagship species to solve a biodiversity conservation conundrum,” Plant Diversity, Jan. 2021, doi: https://doi.org/10.1016/j.pld.2021.01.004.

[12]A. P. Dobson, “Yellowstone Wolves and the Forces That Structure Natural Systems,” PLoS Biology, vol. 12, no. 12, p. e1002025, Dec. 2014, doi: https://doi.org/10.1371/journal.pbio.1002025.

[13]A. Easton-Calabria, K. C. Demary, and N. J. Oner, “Beyond Pollination: Honey Bees (Apis mellifera) as Zootherapy Keystone Species,” Frontiers in Ecology and Evolution, vol. 6, Feb. 2019, doi: https://doi.org/10.3389/fevo.2018.00161.