Transboundary Ecosystem Services Shared by the U.S. and Mexico

A wide range of species, from birds to butterflies, engage in migration – seasonal relocation of populations. As part of our research focusing on transboundary ecosystem services, we are researching the cross-border ecosystem services provided by migratory bats, which rely on habitat in specific locations yet provide valuable ecosystem services, mainly pollination and pest control, in other locations. This situation may present significant policy challenges, as locations that most support a given species may be in effect subsidizing the provision of services in other locations, often in different political jurisdictions.

Large numbers of bats migrate between summer and winter sites in southwestern United States and northern Mexico, establishing large colonies. These bats serve as mobile links connecting ecosystem processes in one location with the provision of ecosystem services in other areas.

For example, two species of endangered, long-nosed bats pollinate blue agave, the main ingredient of tequila. Corporate tequila producers in Mexico currently propagate agave plants vegetatively and only cultivate 1-2 genetic varieties. Pathogens have devastated the genetically homogeneous crops twice, resulting in substantial economic losses. If bats were allowed to pollinate agave, cross-pollination would increase genetic diversity and pathogen resistance. The regulating services provided by long-nosed bats are clearly important for sustainable agave crops.

Another migratory species, the Mexican free-tailed bat, provides critical pest control services for cotton crops in the southwestern United States and northern Mexico. Female bats migrate annually and form large roosting colonies, up to 20 million individuals, from central Mexico to the US-Mexico borderlands. The females feed on agricultural pests - corn earworm and cotton bollworm - providing an estimated $700,000 worth of pest control annually in one region of Texas.

Several factors threaten the bats and the services they provide. Millions of bats have been burned, dynamited, or barred from their roosts by ranchers who mistake them for vampire bats. Bat caves have also been destroyed or disrupted by urban development, highway construction, vandals, and undocumented migrants crossing the US-Mexico border.

To develop a more quantitative understanding of the bats’ migration and habitat needs, we are developing an multi-model that integrates models of Mexican free-tailed bat migration with models of bat ecosystem service provision. This will allow us to quantify how much different regions support the bat populations and to assess bat vulnerability to human-related disturbances including habitat loss, pesticides, and climate change.

Research Team

Laura López-Hoffman E-mail: Ruscena Wiederholt E-mail: Colleen Svancara E-mail:


Market forces and technological substitutes cause fluctuations in the value of bat pest-control services for cotton López-Hoffman, L, R Wiederholt, C Sansone, KJ Bagstad, P Cryan, JE Diffendorfer, J Goldstein, K LaSharr, J Loomis, G McCracken, RA Medellín, A Russell & D Semmens. 2014. PLoS One, 9(2): 7 pages. DOI:10.1371/journal.pone.0087912 (link) National valuation of monarch butterflies suggests untapped potential for incentive-based conservation strategies Diffendorfer, JD, J Loomis, L Reis, K Oberhauser, L López-Hoffman, D Semmens, B Butterfield, K Bagstad, B Semmens, J Goldstein, R Wiederholt, B Mattsson, and W Thogmartin. 2013 (available online October 28, 2013). Conservation Letters, 00: 1-10. DOI:10.1111/conl.12065. (link)

Moving across the border: A conservation modeling approach for migratory bat populations Wiederholt, R, L López-Hoffman, J Cline, R Medellin, P Cryan, A Russell, G McCracken, J Diffendorfer & D Semmens. 2013. Ecosphere, 4 (9): article 114. doi:10.1890/ES-1300023.1 (link)

Tourism values for Mexican free-tailed bats (Tadarida brasiliensis mexicana) Bagstad, K, and Wiederholt, R. 2013. Human Dimensions of Wildlife, 18: 307–311. doi:10.1080/10871209.2013.789573 (link)

How do migratory species add ecosystem service value to wilderness? Calculating the spatial subsidies provided by protected areas López-Hoffman, L, D Semmens & J Diffendorfer. 2013. International Journal of Wilderness, 19 (1): 14–19. Special issue on ecosystem services and wilderness conservation. (link)

Accounting for the ecosystem services of migratory species: quantifying migration support and spatial subsidies Semmens DJ, JE Diffendorfer, L López-Hoffman & C Shapiro. 2011. Ecological Economics, 70 (12): 2236–2242. doi:10.1016/j.ecolecon.2011.07.002 (link)

Ecosystem services across borders: A framework for transboundary conservation López-Hoffman L, RG Varady, KW Flessa, and P Balvanera. 2010. Frontiers in Ecology and the Environment, 8 (2): 84–91. doi:10.1890/070216 (published online 26 Mar 2009). (link)

Conservation of Shared Environments: Learning from the United States and Mexico López-Hoffman L, E McGovern, RG Varady, and KW Fless, eds. 2009. University of Arizona Press. (link)

Finding mutual interest in shared ecosystem services: new approaches to transboundary conservation López-Hoffman L, RG Varady, P Balvanera. 2009. In Conservation of Shared Environments: Learning from the United States and Mexico; L López-Hoffman, E McGovern, RG Varady, & KW Flessa, eds., 137–153. University of Arizona Press. (link)

Sustaining transboundary ecosystem services provided by bats Medellin, RA. 2009. In Conservation of Shared Environments: Learning from the United States and Mexico; L López-Hoffman, E McGovern, RG Varady, and KW Flessa, eds., 170–184. University of Arizona Press. (link)

SUBMITTED Recreation economics of an individual migratory species throughout its annual cycle: Northern Pintail case study Mattsson, BJ, JA Dubovsky, WE Thogmartin, KJ Bagstad, JH Goldstein, J Loomis, JE Diffendorfer, DJ Semmens, and L López-Hoffman. Replacement cost valuation of Northern Pintail (Anas acuta) subsistence harvest in Arctic and sub-Arctic North America Goldstein JH, W Thogmartin, KJ Bagstad, J Dubovsky, D Semmens, BJ Mattsson, L López-Hoffman, and JD Diffendorfer.

Research Partners

Rodrigo Medellin – UNAM Darius Semmens – USGS Rocky Mountain Geographic Science Center Jay Diffendorfer – USGS Rocky Mountain Geographic Science Center Gary McCracken - University of Tennessee, Knoxville Amy Russell - Grand Valley State University

Related Links

USGS Powell Center for Analysis and Synthesis Working group on migratory species and ecosystem services Bat Conservation International Economic Value of the Pest Control Service Provided by Brazilian Free-Tailed Bats in South-Central Texas by CJ Cleveland et al. 2006. (pdf)

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