PARENT SESSION
Oral Session #48: Spatial patterns, spatial processes. Presiding: D. Deutschman.
Wednesday, August 8, 2001. 1:00 PM to 5:00 PM. Madison Ballroom C.

Detection of spatial scales predicting small mammal habitat use in tropical montane cloud forests.

MANSON, ROBERT¹, ¹

ABSTRACT- The importance of considering scale in ecological studies is well established. Studies have demonstrated that the appropriate spatial scale varies depending on the ecosystem and question of interest. Nevertheless, most studies of small mammals continue using small spatial scales to examine the activity and habitat preferences of these organisms. I combined one year of live-trapping data with vegetation surveys conducted at four spatial scales to determine the best scale(s) for studying the habitat use of small mammals in fragments of threatened Mexican cloud forests. Data from five forest fragments located in the center of the state of Veracruz, Mexico, were used in PCA and logistic regression analyses predicting the presence or absence of the most common species encountered in these fragments. These species included Oryzomys alfaroi, Peromyscus aztecus, P. furvos, and Reithrodontomys mexicanus. Results demonstrate: 1) there is no one best spatial scale for studying these organisms, 2) on the contrary, each small mammal species appeared to use a unique combination of spatial scales in space-use decisions, 3) in general, intermediate- and large-scale variation predicted animal activity better than the smaller spatial scales typically used to study small mammal habitat preferences, and 4) there was a general aversion to forest fragment edges which may help explain the nearly 50% decline in small mammal species diversity which has been observed in the region over the last century.

KEY WORDS: spatial scale, tropical montane cloud forest, fragmentation, habitat preferences