Ecosystem services are the benefits obtained from the environment that increase human well-being. 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. Here, we review the available literature on the ecological and economic impact of ecosystem services provided by bats. We 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, we discuss the consequences of these ecological interactions on both natural and agricultural systems. Throughout this review, we highlight the research needed to fully determine the ecosystem services in question. Finally, we 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, we outline a framework that could be used in future studies to more fully address this question. Consumptive goods provided by bats, such as food and guano, are often exchanged in markets where the market price indicates an economic value. Nonmarket valuation methods can be used to estimate the economic value of nonconsumptive 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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Ecosystem services provided by bats

Ecosystem services are natural processes that benefit humans. Birds contribute the four types of services recognized by the UN Millennium Ecosystem Assessment-provisioning, regulating, cultural, and supporting services. In this review, we concentrate primarily on supporting services, and to a lesser extent, provisioning and regulating services. As members of ecosystems, birds play many roles, including as predators, pollinators, scavengers, seed dispersers, seed predators, and ecosystem engineers. These ecosystem services fall into two subcategories: those that arise via behavior (like consumption of agricultural pests) and those that arise via bird products (like nests and guano). Characteristics of most birds make them quite special from the perspective of ecosystem services. Because most birds fly, they can respond to irruptive or pulsed resources in ways generally not possible for other vertebrates. Migratory species link ecosystem processes and fluxes that are separated by great distances and times. Although the economic value to humans contributed by most, if not all, of the supporting services has yet to be quantified, we believe they are important to humans. Our goals for this review are 1) to lay the groundwork on these services to facilitate future efforts to estimate their economic value, 2) to highlight gaps in our knowledge, and 3) to point to future directions for additional research.

Ecosystem Services Provided by Birds

Wind-turbine operations are associated with bat mortality worldwide; minimizing these fatalities is critically important to both bat conservation and public acceptance of wind-energy development. We tested the effectiveness of raising wind-turbine cut-in speed – defined as the lowest wind speed at which turbines generate power to the utility system, thereby reducing turbine operation during periods of low wind speeds – to decrease bat mortality at the Casselman Wind Project in Somerset County, Pennsylvania, over a 2-year period. Observed bat mortality at fully operational turbines was, on average, 5.4 and 3.6 times greater than mortality associated with curtailed (ie non-operating) turbines in 2008 and 2009, respectively. Relatively small changes to wind-turbine operation resulted in nightly reductions in bat mortality, ranging from 44% to 93%, with marginal annual power loss (≤ 1% of total annual output). Our findings suggest that increasing turbine cut-in speeds at wind facilities in areas of conservati...

Altering turbine speed reduces bat mortality at wind-energy facilities

Southeast Asia is a critical area for biodiversity conservation; levels of species richness and endemism are among the highest in the world, but rapid land-use changes endanger much of the region’s fauna. Bats are a critical component of this diversity, comprising nearly a third of Southeast Asia’s mammal species and providing vital ecological and economic services. However, nearly half the species are of conservation concern and as many as 40% of bat species are predicted to be extinct by the end of this century if current deforestation rates persist. Conservation efforts are urgently needed, and the taxonomic continuity of Southeast Asia and the prevalence of major threats throughout suggest that a region-wide initiative could be an effective approach. The Southeast Asian Bat Conservation Research Unit (SEABCRU) was established in 2007 to provide an organizational framework to both accelerate the advancement of bat research, and to coordinate conservation efforts. The SEABCRU is an informal collaboration among institutes, NGOs and individuals and provides a web-based forum for the growing number of researchers and outreach workers to interact and coordinate activities. It was launched at the 1st International Southeast Asian Bat Conference in Thailand (May 2007), during which a forum was held to derive conservation research priorities using a consensus approach. Four priorities were identified by participants: flying fox conservation and monitoring, taxonomy, conservation of cave-dependent bats, and conservation of forest-dependent bats. Here I provide an overview of the rationales behind these priorities and list the specific recommendations for the actions identified.

Research priorities for bat conservation in Southeast Asia: a consensus approach

Pest control service provided by bats in Mediterranean rice paddies: linking agroecosystems structure to ecological functions

Insectivorous bats are major predators of nocturnal insects and have the potential to act as biological pest control agents in farmlands. The objective of the present study was to establish the diet of the guano bat, Tadarida plicata. The study was carried out at the Khao Chong Pran Cave, which houses 2.6 million bats, and is surrounded by rice fields. A total of 1,925 faecal pellets were collected from 385 bats during their morning return from January to December 2002. Faecal analysis indicated that T. plicata fed on at least nine insect orders: Homoptera (28.4%), Lepidoptera (20.8), Hemiptera (16.4), Coleoptera (14.4), Diptera (7.0), Hymenoptera (6.6), Odonata (6.0), Orthoptera (0.5) and Psocoptera (0.1). Light traps indicated that Coleoptera (41.2%), Homoptera (25.3), Hemiptera (18.8) and Diptera (12.7) were the most abundant insects in the study area. Homopterans, most of which were white-backed planthopper (Sogatella sp., Delphacidae) had the highest percentage frequency of occurrence in the bats' diet indicating that T. plicata potentially plays an important role in controlling this major crop pest. The presence of macropterous planthoppers and a large proportion of moths in its diet suggests that T. plicata feeds on windborne migrant insects at high altitude. Female bats fed significantly more on lepidopterans and coleopterans and less on damselflies than males. The diet diversity index of lactating females was higher than pregnant females. Diet did not differ significantly between the dry and rainy seasons for either sex.

Diet of wrinkle-lipped free-tailed bat (Tadarida plicata Buchannan, 1800) in central Thailand: insectivorous bats potentially act as biological pest control agents

Anak Pattanawiboon

Papers

Diet of wrinkle-lipped free-tailed bat (Tadarida plicata Buchannan, 1800) in central Thailand: insectivorous bats potentially act as biological pest control agents