Diet of Andean bears in Tamá National Natural Park, Colombia

Abstract

Abstract: Diet is among the most important and basic ecological aspects of a species. Information on diet composition, seasonality, and spatial variation is necessary for adequate ecological understanding and therefore conservation. Andean bears (Tremarctos ornatus) have been poorly studied across their distribution, and especially in Colombia; therefore, most ecological aspects remain unknown. The objective of this work was to assess Andean bears' diet and seasonality in order to contribute to the knowledge, management, and conservation of the species in northeastern Colombia. Between June 2012 and May 2015, 83 linear transects were surveyed at least once in 35 localities in Tamá National Natural Park in search of fresh bear scats. Transects covered all land-cover types in the park proportionately. We collected 148 scats for diet analyses, and compared all items found with reference material. We assessed diet contents in terms of frequency of occurrence and compared across seasons, elevation, and land-cover types. Overall, plant items showed the greatest frequency of occurrence in the scats (96.8%), followed by mammals (6.7%) and insects (6.7%); we found this pattern for all land-cover types and all elevation ranges. We found seasonal variation and differences in use of some food items. We found the largest niche breadth for the dry season (B = 7.10) compared with the wet season (B = 4.14). Plant items were more frequently consumed during both dry and rainy seasons (0.78 ± 0.16 and 0.82 ± 0.11, respectively) and bromeliads were the most important food item during both seasons (0.32 and 0.46). This variation probably is related to the structure, phenology, and composition of vegetation in the area. More data are needed for estimating foraging preferences and their relationship with food availability and other aspects related to behavior and individual resource use.