In this dissertation, I examined the role of communication, group size, phylogeny, and illegal human harvest (i.e., poaching) in structuring mammalian occurrence, activity, social behavior, and assembly. This research is divided among four dissertation chapters, each representing an independent manuscript, two of which are published. In chapter one, I explored the multiple modalities by which giraffe (Giraffa camelopardalis) communicate. Via an extensive review, I found just 21 studies, published between 1958 and 2018, referencing giraffe communication across visual, olfactory, and auditory dimensions. I found that incorrect generalizations about giraffe communication (such as the belief that this species was mute) were simply a byproduct of inadequate research efforts. In reality, giraffes regularly produce infrasonic sounds, hisses, and low humming vocalizations. Additionally, giraffes have strong visual and olfactory capabilities that they depend on for communication. From this research, I found that giraffes communicate via multimodal signals, but more research is needed to examine the intent and context of communication. In chapter two, I examined the ways researchers estimate ungulate group sizes. Spatial extents (i.e., nearest neighbor distances) over which ungulate group sizes were defined ranged between 1.4 m to 1000 m whereas temporal extents ranged between three minutes to 24 hours. The variability in group size definitions that I observed complicates efforts to not only compare and replicate studies, but also to evaluate underlying theories of group living. In chapter three, I examined the prevalence and spatial distribution of giraffes with snaring injuries in Murchison Falls National Park (MFNP), Uganda. Via photographic spatial encounter surveys and using coat patterns to identify animals, I observed a subadult/adult population of 1,306 and estimated 1,892 (±78) using a spatial capture-recapture model. Model predictions showed that only 1.3% of the population had a snaring injury, and these individuals were concentrated on the western end of the park close to the River Nile shores. Individual giraffes with highest movement rates in the landscape had higher chances of being snared. I contend that even when giraffes are not targeted by poachers, they can still experience important individual-level effects from wire snares. Finally, in chapter four, I examined the role of body mass and phylogeny in predicting mammal activity in MFNP. My results indicated that phylogeny is a statistically-stronger predictor of mammal activity levels (time spent active in 24-hours) than body mass. These results suggest that variation in activity among co-occurring mammals is structured with respect to phylogeny. Thus, phylogeny plays a critical role in mammal community assembly. Overall, my research emphasizes a broad scale and multidimensional evaluation of mammal occurrence and assembly.
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