Get reliable rangeland science

Ranching and hunting are two major land uses on the Edwards Plateau. Sheep (Ovis aries) and goats (Capra hircus) often share rangeland with native white-tailed deer (Odocoileus virginianus) and introduced species such as Axis deer (Cervus axis). Competition is possible among these animals. Each of these species produce morphologically-similar pelleted feces. Field identification of feces from these sympatric herbivores will facilitate management. An experiment was conducted to determine the ability of near infrared spectroscopy (NIRS) to identify fecal samples by species, age class, and sex. Fresh (< 1hr) sheep and goat fecal samples (50 � 5g) were collected off the ground from free-ranging groups of: male, female, adult, sub-adult, and juvenile animals during late July-early August (Period 1, n = 32) and late August-early September (Period 2, n = 69) 2016. Samples were similarly collected from free-ranging white-tailed (n = 10) and Axis (n = 14) deer during the same periods. Samples were placed on ice in the field and stored at -20 C until processed for NIRS. Spectra (400-2500nm) were used to develop discriminant calibrations via 2-block partial least squares. Percent fecal nitrogen (FN) was determined using existing NIRS calibrations. Differences between groups for FN were determined using analysis of variance. Percent correct identification of groups was variably successful: collection period (98%), species (70%), age class (89%), sex (83%). Generally, FN increased (P < 0.01) from Period 1 (1.69 � 0.05) to Period 2 (1.92 � 0.03) but was dependent on species. For instance, FN was 1.47 � 0.03 and 1.85 � 0.12 (P < 0.01; sheep), 1.80 � 0.15 and 2.08 � 0.09 (P > 0.1; white-tailed deer) for Period 1 and 2 respectively. With larger calibration datasets, fecal NIRS could be used to provide management information for sympatric free-ranging herbivores in this savanna rangeland habitat.