PARENT SESSION
Oral Session #71: Remote Sensing and GIS.
Presiding: J.D. Allan
Wednesday, August 7. 1:00 PM to 4:45 PM. Palo Verde Room, Radisson.
Modeling aplomado falcon (Falco femoralis septentrionalis) breeding habitat in the Chihuahuan Desert using a landscape perspective.
YOUNG, KENDAL1, BROWNING, DAWN*,1, LANSER, JULIE2, THOMPSON, BRUCE1, 1 NEW MEXICO COOPERATIVE FISH AND WILDLIFE RESEARCH UNIT, LAS CRUCES, NM2 DEPARTMENT OF GEOGRAPHY, LAS CRUCES, NM
ABSTRACT- The northern aplomado falcon, listed as an endangered species in 1986, historically inhabited semi-desert grasslands in the Chihuahuan Desert. Although they apparently declined rapidly in the U.S. after the 1930s, a viable population exists in northern Chihuahua, Mexico. The study area (257,000 km2) encompasses portions of Mexico, New Mexico, and Texas. Site locations for falcon nests in Chihuahua were used as a basis for a predictive model applied to this study area. We examined 2.53 km2 buffers around use sites (n=42) and used Landsat 7 ETM+ data (spectral reflectance and classified imagery), MSAVI vegetation index, and landscape metrics to describe falcon use areas. We employed a multitemporal approach by analyzing dry (late spring) and wet (late fall) seasons of imagery. We compared falcon use areas with available habitat represented by 100 random points from northern Chihuahua using an Analysis of Variance. There were significant differences in three landscape metrics between use and random sites. Patch richness density in the spring (p < 0.0001) and fall (p=0.0118) was higher for random sites than use sites. Interspersion Juxtaposition Index for spring (p=0.009) was higher for random sites than use sites suggesting that falcon sites were found in areas with fewer, less interspersed patch types than that of the overall landscape. Chi-square goodness of fit test was used to determine whether classes were used in proportion to their availability. One of 26 classes in fall image containing 40% of sites (p < 0.0001) and one of 33 classes in spring image containing 30% of sites (p < 0.0001), were used in greater proportion than were available. Variables will be included in logistic regression procedure to identify variables important in site selection. The predictive habitat model will aid in making conservation decisions and focusing habitat management for the aplomado falcon.
KEY WORDS: remote sensing/GIS, habitat model, grassland raptor, Falco femoralis septentrionalis