Biodiversity Factsheet

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Biodiversity, or biological diversity, is the variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part.1 Biodiversity shapes the ecosystem services that contribute to human well-being—material welfare, security, social relations, health, and freedom of choice.2 Biodiversity is considered on three levels: species diversity, genetic diversity, and ecosystem diversity.3

Species Diversity

  • Species diversity can be measured in several ways, including diversity indices (species richness and evenness), rank abundance diagrams, and similarity indices.4
  • There are an estimated 8.7 million eukaryotic species on earth, of which 86% of land species and 91% of ocean species have not yet been described.5
  • 1.2 million species have been described globally.5
  • 59,923 plant and animal species are listed in the U.S.; top-ranking states for species diversity are CA, TX, AZ, NM, and AL, respectively.6,7
  • Freshwater habitats account for only 0.01% of the world’s water and make up less than 1% of the planet’s surface, but they support one-third of all described vertebrates and nearly 10% of all known animal species.8
  • One study suggests Arctic and Antarctic waters, not tropical reefs, are hotspots of fish speciation—contrary to much of the previous thinking about evolution.9

Catalogued Earth and Ocean Species5

Catalogued Earth and Ocean Species

Genetic Diversity

  • Genetic diversity refers to the genetic variation within species (for both the same population and populations living in different geographical areas).3
  • Individuals within a species have slightly different forms of genes through mutations, where alleles can code for different proteins and ultimately affect species physiology.3
  • Genetic variations lead to differences in both genotype and phenotype, which are necessary for species to maintain reproductive vitality, resistance to disease, and the ability to adapt to changing conditions.3

Community/Ecosystem Diversity

  • Ecosystem diversity describes different biological communities and their associations with the ecosystem in which they are part.3
  • Within these ecosystems, species play different roles and have different requirements for survival (i.e., food, temperature, water, etc.). If any of these requirements become a limiting resource, a species population size becomes restricted.3

genotype vs. Phenotype3

Genotype vs. Phenotype

Goods & Services

  • Ecosystem services are the conditions and processes that enable natural ecosystems to sustain human life.10
  • Ecosystem services include: air and water purification; mitigation of floods and droughts; detoxification and decomposition of wastes; generation and renewal of soil and soil fertility; pollination of crops and natural vegetation; dispersal of seeds and translocation of nutrients; protection from the sun’s harmful ultraviolet rays; partial stabilization of climate; and moderation of temperature extremes and the force of winds and waves.10
  • Biodiversity increases several ecosystem services, including crop yields, stability of fishery yields, wood production, fodder yield, resistance to plant invasion, carbon sequestration, soil nutrient mineralization, and soil organic matter.11
  • These services provide goods, such as seafood, forage, timber, biomass fuels, natural fiber, pharmaceuticals, industrial products, and more.10

Biodiversity, Ecosystem Services, and Human Well-Being2

Biodiversity, Ecosystem Services, and Human Well-Being

Loss of Biodiversity

  • In the last 50 years, alteration of biodiversity related to human activities was greater than any time in human history, driven by habitat loss from agriculture, infrastructure, over-exploitation, pollution, and invasive alien species.2,12
  • Climate change is potentially a pervasive threat to biodiversity, because it can affect areas uninhabited by humans.14 Higher temperatures could increase drying, resulting in dieback in the Amazon, which has the highest biodiversity of all forests.15
  • As of August 2019, 76,000 fires were burning over 7,000 square miles of the Amazon, an 80% increase in fires from August 2018.16
  • Habitat loss increases greenhouse gas emissions; 8% of global emissions (.8-.9 GtC) derive from tropical deforestation.17 Tropical forests sequester 1.2 - 1.8 GtC yearly.17
  • Over-fishing and harvesting also contributes to a loss of genetic diversity and relative species abundance of individuals and groups.18
  • Up to 1 million species may be threatened with extinction in the coming decades, without mitigation of biodiversity loss, the extinction rate will continue to rise.19

Major Threats to Critically Endangered Vertebrates12

Major Threats to Critically Endangered Vertebrates

Biodiversity Loss Due to Agriculture

  • Of the 30 mammalian and bird species used extensively for agriculture, half account for over 90% of global livestock production.20
  • Genetic diversity within breeds is declining, and 17% of 8,774 livestock breeds identified are classified as at risk.21
  • Of 30,000 wild edible and 7,000 cultivated plants, 30 provide 95% of dietary energy or protein. Wheat, rice, and maize provide over 50% of plant-derived calories, globally.22
  • In the last 100 years, about 75% of the genetic diversity of agricultural crops was lost.23 Productivity, stability, ecosystem services, and resilience are positively associated with species diversity in agricultural ecosystems.24


  • In earth’s history, there have been five mass extinctions defined as time periods where extinction rates accelerate relative to origination rates such that over 75% of species disappear over an interval of 2 million years or less.25
  • Globally, 1% or less of the species within most assessed taxa are extinct. However, 20-43% of species in these taxa are labeled as threatened.25 
  • 236 plant and animal species have gone extinct in the U.S. and 2284 are threatened or endangered.6,26
  • Current extinction rates are higher than those leading to the five mass extinctions, and could reach mass extinction magnitude in three centuries.25

Federally Listed Endangered Species by Taxonomic Group13

Federally Listed Endangered Species by Taxonomic Group

Sustainable Actions


  • Examples of treaties to protect species include: The Convention on Wetlands of International Importance (1971); The Convention of International Trade in Endangered Species (1973); The Convention of the Conservation of Migratory Species of Wild Animals (1979); and the Convention on Biological Diversity (CBD) (1992).27
  • The Endangered Species Act (1973), administered by the Interior Department’s Fish and Wildlife Service and the Commerce Department’s National Marine Fisheries Service, aims to protect and recover imperiled species and the ecosystems they depend on.28
  • 190 parties have National Biodiversity Strategic Action Plans for the conservation and sustainable use of biological diversity.29
  • Over 209,000 protected areas (such as national parks and reserves) have been established, 23 times more than in 1962, covering around 13% of the Earth’s land surface and less than 1.5% of marine areas.12,30

Global Initiatives

  • The Strategic Plan for Biodiversity 2011-2020 is a framework of five strategic goals and twenty Aichi Targets adopted by the Convention on Biological Diversity in 2010.31 However, these goals will not be achieved if current trends continue or worsen, and will undermine other goals set forth in the Paris Agreement and the 2050 Vision for Biodiversity.19
  • The United Nations developed a list of Sustainable Development Goals (SDG’s) in 2015 that commit to preserving biodiversity of aquatic and terrestrial organisms, among other things. Fulfilling the SDG’s has the potential to greatly increase biodiversity and its associated benefits.32
  1. United Nations (UN) Treaty Series (1993) Convention on Biological Diversity. Vol. 1760, I-30619.
  2. Millennium Ecosystem Assessment (2005) Ecosystems and Human Well-being: Biodiversity Synthesis. World Resources Institute, Washington, DC.
  3. Primack, R. (2010) Essentials of Conservation Biology. Sunderland, MA: Sinauer Associates, Inc.
  4. Stiling, P. (2015) Ecology: Global Insights & Investigations. New York, NY: McGraw-Hill Education.
  5. Mora, C., et al. (2011) How Many Species Are There on Earth and in the Ocean? PLoS Biol 9(8): e1001127.
  6. NatureServe (2019) NatureServe Explorer: An online encyclopedia of life. Version 7.1. Arlington, Virginia.
  7. NatureServe (2002) States of the Union: Ranking America’s Biodiversity.
  8. Strayer, D. and D. Dudgeon (2010) “Freshwater biodiversity conservation: recent progress and future challenges.” Journal of the North American Benthological Society, 29(1): 344-358.
  9. Daniel, R., et al. (2018) “An inverse latitudinal gradient in speciation rate for marine fishes.” Nature 559: 392–395.
  10. Daily, G. (1997) Nature’s Services: Societal Dependence on Natural Ecosystems. D.C.: Island Press.
  11. Cardinale, B., et al. (2012) “Biodiversity loss and its impact on humanity.” Nature 486:59-67.
  12. UN Environmental Programme (UNEP) (2012) Global Environment Outlook (GEO-5).
  13. U.S. Fish and Wildlife Service (2017) “Species Reports.”
  14. Malcolm, J., et. al. (2006) “Global warming and extinctions of endemic species from biodiversity hotspots.” Conservation Biology, 20: 538–550.
  15. Stern, N. (2007) The Stern Review: The Economics of Climate Change. Cambridge Univ. Press.
  16. National Geographic (2019) “See how much of the Amazon is burning, how it compares to other years.”
  17. International Sustainability Unit (2015) “Tropical Forests: A Review.”
  18. Fulekar, M. (2010). Environmental Biotechnology. Boca Raton, FL: Taylor & Francis Group.
  19. Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2019) “Summary for policymakers of the global assessment report on biodiversity and ecosystem services”
  20. Food and Agriculture Organization of the United Nations (UN FAO) (2006) The Role of Biotechnology in Exploring and Protecting Agricultural Genetic Resources.
  21. UN FAO (2015) The Second Report on the State of the World’s Animal Genetic Resources for Food and Agriculture.
  22. UN FAO (1997) State of the World’s Plant Genetic Resources for Food and Agriculture.
  23. UN FAO (2004) Building on Gender, Agrobiodiversity and Local Knowledge.
  24. Khoury, C., et al. (2014) “Increasing homogeneity in global food supplies and the implications for food security.” Proceedings of the National Academy of Sciences, 111(11), 4001–4006.
  25. Barnosky, A., et al. (2011) “Has the Earth’s sixth mass extinction already arrived?” Nature 471:51–57.
  26. U.S. Fish & Wildlife Services (2019) “All Threatened & Endangered Animals & Plants.”
  27. Pierce, D. (2007) “Do we really care about biodiversity?” Environmental and Resource Economics, 7 (1): 313-333.
  28. U.S. Fish and Wildlife Service (2009) More than 20 Years of Conserving Endangered Species.
  29. UNEP (2018) National Biodiversity Strategies and Action Plans.
  30. UNEP (2014) United Nations List of Protected Areas.
  31. Secretariat of the Convention on Biological Diversity (2010) Strategic Plan for Biodiversity 2011-2020 and the Aichi Targets.
  32. United Nations (2019) “Sustainable Development Goals”
Cite as: 
Center for Sustainable Systems, University of Michigan. 2019. "Biodiversity Factsheet." Pub. No. CSS09-08.