New Study Highlights Importance of Ecosystem Services Provided by Bats

Newswise — BOSTON—Thomas H. Kunz, Warren Distinguished Professor and director of Boston University’s Center for Ecology and Conservation Biology, and a team of researchers, including Elizabeth Braun de Torrez, graduate student in BU’s Department of Biology; Dana M. Bauer, assistant professor in BU’s Department of Geography and Environment; Tatyana Lobova, assistant professor in Old Dominion University’s Department of Biology; and Theodore H. Fleming, emeritus professor of biology at the University of Miami and adjunct professor of ecology and evolutionary biology at the University of Arizona, recently published an important review paper on “Ecosystem Services Provided by Bats” in the journal Annals of the New York Academy of Sciences.¹

This paper follows a seminal study entitled “Economic Importance of Bats in Agriculture,” published in the April 1, 2011 issue of the journal Science². Together, these papers show dramatically how bat populations in North America are declining from two catastrophic assaults within their ecosystems: a devastating fungal disease that has killed over one million hibernating bats in the northeastern U.S. within the past four years, and the continuing adverse impacts from the development of wind-energy. Together, these papers raise an important question that is often asked by policy makers and the general public: “Why should we care about bats?”

Based on current knowledge, we should care because natural ecosystems throughout the world have become increasingly threatened by anthropogenic (human generated) factors such as urbanization, mining, deforestation, chemical and light pollution, and invasive species. Healthy ecosystems are especially important in providing various regulatory processes (such as insect suppression, pollination, seed dispersal, purification of water and air, stabilization of soils, decomposition of wastes, binding of toxic substances, mitigation of diseases, mitigation of floods, and regulation of climate), products or provisions (food, fuel, fiber, and medicines), supporting processes (nutrient cycling, soil formation, and primary production), and cultural benefits (aesthetic, spiritual, educational and recreational) that improve the overall well-being of humans. These processes and products are commonly referred to as ecosystem services and have been formally designated as such by the United Nations Millennium Ecosystem Assessment. Ecosystem services are the benefits obtained from the environment that increase human wellbeing and vary depending on the ecosystems and the organisms they constitute.

Kunz and his coauthors review the role of bats in providing ecosystem services, focusing primarily on those that regulate and provide services needed to sustain humankind, with a brief overview of supporting and cultural services. One of the grand challenges that society faces is how best to identify, protect and conserve services that are critical for human and ecosystem health. Economic valuation is conducted by measuring the human welfare gains or losses that result from changes in the provision of ecosystem services. Bats have long been postulated to play important roles in arthropod suppression, seed dispersal and pollination; however, only recently have these ecosystem services begun to be thoroughly evaluated. Kunz and his colleagues describe dietary preferences, foraging behaviors, adaptations and phylogenetic histories of insectivorous, frugivorous and nectarivorous bats worldwide in the context of their respective ecosystem services. For each trophic ensemble they discuss the consequences of these ecological interactions on both natural and agricultural systems.

Throughout the review, the authors highlight the types of research that are needed to quantify the ecosystem services in question. Finally, they provide a comprehensive overview of economic valuation of ecosystem services. Unfortunately, few studies estimating the economic value of ecosystem services provided by bats have been conducted to date; however, they outline a framework that could be used in future studies to more fully address this question. For example, consumptive goods provided by bats, such as food and guano, are often exchanged in markets where the market price indicates an economic value. Non-market valuation methods can be used to estimate the economic value of non-consumptive services, including inputs to agricultural production and recreational activities. Information on the ecological and economic value of ecosystem services provided by bats can be used to inform decisions regarding where and when to protect or restore bat populations and associated habitats, as well as to improve public perception of bats.

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¹Kunz, T.H., E. Braun de Torrez, D.M. Bauer, T.A. Lobova, and T.H. Fleming. 2011. Ecosystem services provided by bats, in “The Year in Ecology and Conservation,” eds, R.A. Ostfeld and W.H. Schlesinger. Special issue, Ann. N.Y. Acad. Sci. 1223, 1-38.

²Boyles, J.G., P.M. Cryan, G.F. McCracken, and T.H. Kunz. 2011. Economic importance of bats in agriculture. Science, 332: 41-42.