SIGNS AS A TOOL FOR DETECTING TRENDS IN CARNIVORE POPULATIONS FROM SOUTHERN ARGENTINE PATAGONIA

DIEGO PROCOPIO; ALEJANDRO TRAVAINI; SONIA C. ZAPATA; ALEJANDRO RODRÍGUEZ; ROLANDO MARTÍNEZ-PECK; JUAN IGNACIO ZANÓN MARTÍNEZ; MIGUEL ÁNGEL SANTILLÁN; JULIETA PEDRANA

Congreso; 10th International Mammal Congress; 2009

We developed and tested a simple method to monitor population trends in three carnivore species: culpeo and grey foxes (Lycalopex culpaeus and L. griseus) and pumas (Puma concolor) by sign quantification. From 2002 to 2008 we searched for carnivore feces in 4-km2 square plots in the protected area “Monumento Natural Bosques Petrificados” (MNBP) located in southern Argentina Patagonia. The mean number of surveyed plots per season was 86 (range 45-116), and the mean sampling effort was 3 km per plot (range 2.5– 4.1). The number of feces found in plots, corrected by sampling effort, were used to analyze population trends applying log-linear models with the program TRIM (TRends & Indices for Monitoring Data, Statistics Netherlands). From 2002 to 2008, the overall population trend for culpeos was negative corresponding to an annual decrease of 11.6% (trend value 0.8800; p<0.05) and was considered as a moderate decline). Nevertheless, this decline was not steady over time, and population fluctuations were detected between years: decrease until 2003 (Wald test = 18.66, df =1, p<0.001); increase from 2005 to 2007 (Wald test = 18.46, p <0.001), and decrease from 2007 to 2008 (Wald test = 14.05, df = 1; p <0.01). In contrast, the overall trend for grey foxes was positive (trend value 1.133 p<0.01), and corresponded to an annual increment of 13.4%, considered as a strong increase. No trend was detected for the puma during the study period (trend value = 1.0736). This methodology, simple and inexpensive, although time consuming, allowed us to detect population changes in both fox’s species. Our results can be discussed in the context of competitive interactions among this carnivore species.