Final Project: Bats and Climate Change in New Mexico

Background

Bats are important in many ways, from keeping insect populations down, pollinating plants, fertilization of crops with guano, to medicinal benefits derived

from anti-coagulant in the saliva of vampire bats (Kunz et al 2011)

Canyon bat, Parastrellus hesperus

It has been shown that bats have greater water needs than other mammals of similar size due to their large surface area to volume ratio. Mother bats in particular

require a great deal of water to support lactation (Adams 2010). A recent study showed that lactating bats visited a water source 13 times more often than non-lactating

female bats (Adams et. al. 2008). Decreasing precipitation that is associated with climate change (Saunders et. al. 2008) therefore holds significant declines for bat

populations. (Figures 1A and 1B)

The ways for biological organisms to respond to climate change are few: they can move (increase their range latitudinally or elevationally), they can adapt, or they will

likely go extinct (Parmesan 2006). I tested for changes in elevation for bats in New Mexico from the 1960s to 2013 using GIS techniques.

Big brown bat, Eptesicus fuscus

Methods

My study site consists of Grant and Sierra counties in southwestern New Mexico. I chose this area because it contains a mix of public lands (US Forest Service, grazing

allotments) and private land (Ted Turner’s Ladder Ranch, which is ungrazed). (Figure 2)

I acquired my bat occurrence data from the 1960s, 1995, and 2012-2013 from http://arctos.database.museum/home.cfm. My source for DEM and image data were

http://rgis.unm.edu, and my source for precipitation and temperature data is http://www.prism.oregonstate.edu/.

Results

Bats are indeed occurring at higher elevations in Grant County in the modern era (1995-2013) as compared to the 1960s. (Figure 3) However there was no significant

difference in elevational occurrence for modern v. 1960s bats in Sierra County (Figure 4). When Sierra County v. Grant County elevation was compared, there was a

significant difference with Grant County bats occurring at a higher elevation for modern and historical data (Table 1).

From these results it appears possible that climate trends are affecting bat populations in the southwest as evidenced by elevation increase seen in Grant County. When

this data is coupled with the increase in temperature and decrease in precipitation in the southwest, it stands to reason that bats are attempting to meet their high precipitation

demands by moving upward in elevation.

Mexican free-tailed bat, Tadarida brasiliensis, and Boston terrier, Canis lupus familiaris