Midden site selection in Dorcas gazelle
Soultan, Alaaeldin; Nagy, Abdullah; Attum, Omar (2023), Midden site selection in Dorcas gazelle, Dryad, Dataset, https://doi.org/10.5061/dryad.05qfttf3p
Dorcas gazelles are believed to use middens to mark their territories and transmit information. Given the commitment to maintaining a midden, it is believed that middens are not placed randomly. We examined how the habitat (tree height and maximum canopy) and anthropogenic disturbance (camel and human presence) influenced the selection of midden sites by Dorcas gazelles in South Sinai, Egypt. Our results showed that Dorcas gazelles did not place middens at larger trees, while favoring relatively smaller trees and shrubs where the anthropogenic disturbance and perceived hunting risk is less. Our results, in light of the previous findings, suggest that selection of midden sites is species-context-dependent behavior. In areas with less anthropogenic disturbance and hunting, Dorcas gazelles have been shown to select the largest trees of the same species as midden sites. In contract, in our study site with high anthropogenic disturbance and no protection from hunting, gazelles did not utilize the presumably optimum landmarks for midden sites. Our study showed that Dorcas gazelles instead utilized smaller trees and some shrubs that are less conspicuous and presumably less effective as advertisement sites, but safer.
We delineated boundaries for the nine Acacia groves available in the study area. We randomly selected 30 points to survey among the nine patches (minimum 2 points/grove according to grove size). One out of these 30 points was excluded from our survey because it was located on the slope of a mountain. For each point, we surveyed all the trees and shrubs within a 100 m radius of the point. We then collected the following data for each point: date, tree and shrub species, maximum tree height (measured with a clinometer), and the maximum tree canopy diameter. If a midden was located, then we also recorded the same attributes for the nearest tree, even if it was located outside the 100 m radius. We also recorded the presence of camels, and humans within a 10 m radius from the base of a tree. A midden was defined as an accumulation of gazelle fecal pellets that covered an area of ≥50 cm2. We considered only middens with relatively fresh deposited (i.e., black or dark brown) fecal pellets. Camel's presence was determined through the presence of tracks or fecal pellets. Humans were considered present if there were footprints, remains of campfires, or vehicle tracks. The survey and data collection were conducted between May 27, 2012 – June 1, 2013.