Biology subjects

Ohrndorf, L.

Publications and source records attributed to Ohrndorf, L..

4 recordsLinked to original sources

bioRxiv2026

Diversity and spatiotemporal activity patterns of medium and large mammals in the Niokolo-Koba National Park, Senegal

West African savannahs provide habitats to diverse species assemblages, yet remain understudied compared to their East and Southern African counterparts. The Niokolo-Koba National Park in southeastern Senegal constitutes one of the largest remaining protected areas in West Africa and supports a mosaic of savannah and forest habitats with a diverse assemblage of medium- and large-sized mammals. Here, we analysed camera-trap data originally collected to monitor predator presence in the northwestern sector of the National Park. We deployed 37 cameras across 37 km{superscript 2} from February 2022 to March 2023, resulting in 13,161 camera-trap-days. We assessed alpha diversity indices and spatiotemporal activity patterns of large and medium-sized mammals across habitat types. Evenness values - the degree to which species abundances are distributed uniformly within a community - were higher in the savannah than in forest habitats, although overall species richness was comparable. In contrast, animal sighting rates were higher in forests than in savannahs. Estimated diel activity mostly corresponded with established species-specific behavioural patterns. Our analyses revealed differential use of certain habitat types across the day, likely driven by spatially segregated sleeping sites and foraging locations. Our results provide a reference for future studies and monitoring efforts and highlight the value of the forest-savannah mosaic for the local species assemblage within the larger ecosystem of Niokolo-Koba National Park.

ecology↗

bioRxiv2025

Rapid updating of ecological information in wild Guinea baboons

Knowing where to find what kind of food when is essential for survival and reproduction. Recent links between feeding ecology and brain size have revived interest in foraging cognition as a core component in cognitive evolution. We investigated whether free-ranging Guinea baboons (Papio papio) keep track of the spatio-temporal availability of a preferred food resource, the Natal orange (Strychnos spinosa). A natural experiment, a massive wildfire that destroyed most oranges in 2019, allowed us to disentangle habitual routines from goal-directed behaviour in the baboons. The animals space-use patterns shifted significantly following the wildfire. After one single visit, they stopped going to the area during the period when Natal oranges would normally be available. In the following year, they resumed regular space-use patterns. We also assessed travel linearity, speed, and departure time from sleeping sites towards the target area with and without ripe fruit. Guinea baboons travelled more linearly, 14% faster, and ~40 minutes earlier towards the target area when S. spinosa was in season compared to when it was not. In conclusion, Guinea baboons rapidly updated their knowledge of high-value food availability and adjusted their space-use accordingly. These results underscore their capacity for flexible decision-making and goal-directed foraging.

animal behavior and cognition↗

bioRxiv2025

Patterns of sleeping site use of Guinea baboon parties (Papio papio)

Sleeping site use in primates is thought to be influenced by multiple factors, including resource availability and competition, predation risk, and the risk of parasitic infection. While previous research has highlighted the importance of these factors, few studies have examined sleeping site use among multiple groups of non-territorial species with overlapping home ranges. Here, we investigated the sleeping site use of Guinea baboons (Papio papio) in Simenti, Senegal. We used locational data for four years of several baboon parties sharing the same range. We assessed the distribution of sleeping sites within the local habitat mosaic, the proximity of sleeping sites to those of co-occurring parties and the impact of food availability and predator presence at the landscape level on the distance between parties sleeping sites on the same night. We further investigated patterns of sleeping site use of parties across time. We found that the vast majority of sleeping sites were in the gallery forest along the perennial Gambia River, likely due to the availability of tall trees. Guinea baboons slept in close spatial proximity (>50m) to at least one other party regardless of food availability and predator presence. Patterns of sleeping site use showed no evidence of predator or parasite avoidance. Thus, Guinea baboons in Simenti likely use the abundantly available sleeping sites opportunistically rather than being driven by intergroup competition or strategies for predator avoidance or reduction of the risk of parasite infection.

ecology↗

bioRxiv2024

Patterns of landscape partitioning indicate low levels of resource competition among neighbouring Guinea baboon(Papio papio) parties

BackgroundAccess to critical resources, including food, water, or shelter, significantly determines individual fitness. As these resources are limited in most habitats, animals may employ strategies of landscape partitioning to mitigate the impact of direct resource competition. Territoriality may be regarded as an aggressive form of landscape partitioning but in non-territorial species, other forms exist. Animals living in groups with greater flexibility in their association patterns, such as multilevel societies with fission-fusion dynamics, may adjust their grouping and space use patterns to short-term variations in ecological conditions such as food availability, predation pressure, or the presence of conspecific groups. This flexibility may allow them to balance the costs of competition while reaping the benefits of better predator detection and defence. MethodsWe explored patterns of landscape partitioning among neighbouring Guinea baboon (Papio papio) parties in the Niokolo-Koba National Park, Senegal. Guinea baboons live in a multilevel society in which parties predictably form higher-level associations ("gangs"). We used four years of locational data from individuals equipped with GPS collars to estimate annual home ranges, home range overlap, and minimum distances between parties. We examined whether food availability and predator presence levels affected the cohesion between parties in 2022. ResultsWe found substantial home range and core area overlap among parties (33 to 100%). We found no effect of food availability or predator presence on the distance to the closest neighbouring party; the minimum distance between parties was less than 100 m on average. ConclusionsOur results suggest a low level of feeding competition between our study parties. Whether this is a general feature of Guinea baboons or particular to the situation in the Niokolo-Koba National Park remains to be investigated.

ecology↗