Spatial and temporal niche overlap of aardwolves and aardvarks in Serengeti National Park, Tanzania
Description
Species interactions can influence species distributions, but mechanisms mitigating competition or facilitating positive interactions between ecologically similar species are often poorly understood. Aardwolves (Proteles cristata) and aardvarks (Orycteropus afer) are nocturnal, insectivorous mammals that co-occur in eastern and southern Africa, and knowledge of these species is largely limited to their nutritional biology. We used aardwolf and aardvark detections from 106 remote cameras during 2016–2018 to assess their spatial and temporal niche overlap in the grasslands of Serengeti National Park, Tanzania. Using a multispecies occupancy model, we identified a positive interaction between occupancy probabilities for aardwolves and aardvarks. Slope, proportion of grassland, and termite mound density did not affect occupancy probabilities of either species. Probability of aardwolf, but not aardvark, occupancy increased with distance to permanent water sources, which may relate to predation risk avoidance. Diel activity overlap between aardwolves and aardvarks was high during wet and dry seasons, with both species being largely nocturnal. Aardwolves and aardvarks have an important ecological role as termite consumers, and aardvarks are suggested to be ecosystem engineers. Our results contribute to a better understanding of the spatial and temporal niche of insectivores like aardwolves and aardvarks, suggesting high spatial and temporal niche overlap in which commensalism occur, whereby aardwolves benefit from aardvark presence through increased food accessibility.
Methods
We collected data during August 2016–June 2018 using 106 remote cameras (Stealth Cam, model N45NG; Irving, Texas, USA). Nearest distance between cameras was 3,000 m for 63 cameras and 4,225 m for 43 cameras (Figure 1). We attached cameras to metal stakes 50-cm above ground and cleared vegetation in front of cameras. We programmed cameras to record 3-image bursts at each detection with a 30-second delay and inspected each about every 6 weeks. Because of staggered camera installations, we extracted data for a period of 70 consecutive days from each camera (hereafter a "camera-period") during 26 August 2016–1 January 2018, and a second 70-day camera-period for 77 cameras during 22 January 2017–30 June 2018. Overlap between the two periods of data collection occurred due to staggered camera installation. Most (95%) data were obtained during September 2016–February 2018. Each 70-day camera-period was associated with a season (wet season, November-May; dry season, June-October). If a camera-period overlapped two seasons, we split the data by season into two separate, shorter camera-periods each entirely with one season.
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Additional details
Related works
- Is derived from
- 10.5281/zenodo.8367436 (DOI)