Between Dec 19, 2024 and Jan 2, 2025, datasets can be submitted to DRUM but will not be processed until after the break. Staff will not be available to answer email during this period, and will not be able to provide DOIs until after Jan 2. If you are in need of a DOI during this period, consider Dryad or OpenICPSR. Submission responses to the UDC may also be delayed during this time.

Browsing by Subject "Gombe National Park"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Forest and woodland regeneration dynamics and persistence in the human- modified landscape of Greater Gombe Ecosystem, Tanzania
    (2023-08) Kimaro, Elihuruma
    AbstractThe clearing of tropical forests and woodlands for human use puts many species at risk of extinction. Vast areas of forests and woodlands have been converted to fragmented patches located within mosaics of different land uses (e.g., agricultural lands and human settlements). Some conservationists have argued that community-managed forests can be an effective strategy for promoting forest regeneration, persistence of mature forest patches, and conservation in human-modified landscapes. However, few studies have systematically evaluated its effectiveness. In particular, limited empirical evidence exists on the influence of these reserves on promoting the persistence and recovery of forest structure, carbon stock, and feeding habitat quality for vulnerable species, such as chimpanzees. To properly assess the influence of this management strategy, we need to take into account other factors likely to affect forest attributes, including, topographic factors (e.g., slope), anthropogenic factors (e.g., wildfire), and plant functional traits (e.g., dispersal mode) on the variation of forest structure in these reserves. To provide insights on these issues, I used various data sources to assess forest cover changes, factors affecting those changes, and patterns of forest structure, composition, carbon stock, and feeding habitat quality for primates in 16 Village Land Forest Reserves (VLFRs) in the Greater Gombe Ecosystem (GGE), in western Tanzania. The data sources include, remote sensing confirmed with ground-truthing, forest inventory plots, spatially explicit forest monitoring data, and previously collected information on primate food tree preference. These VLFRs were established through a community-based planning process, facilitated by the Jane Goodall Institute and the Tanzanian government. In this dissertation, I used three chapters to assess the effectiveness of community forest management at this site. In Chapter 1, I used multi-temporal satellite images from 2006, 2013, 2016, and 2021 to assess possible pathways of forest and woodland cover change in these reserves compared to unprotected village land. In Chapter 2, I quantify the relative influence of topographic and anthropogenic factors on the variation of forest cover change in these reserves. In Chapter 3, I determined how VLFRs promoted permanence and recovery of forest structure, carbon stock, and feeding habitat quality for primates and compared them with a nationally protected area, the Gombe National Park representing the reference scenario. Also in Chapter 3, I assess the relative influence of anthropogenic and topographic factors, as well as plant functional traits on the variation of forest structure in VLFRs. My results show that (1) between 2006 and 2021, forest cover increased by 66% in the area designated as VLFRs but declined by 22% in unprotected village land; (2) accounting for factors such as forest age, and iv topography, the factors that most impacted forest cover included a negative impact of fire frequency and a positive impact of village-led patrol effort; and (3) in comparison to the mature woodlands in the VLFRs, the second-growth woodlands in the VLFRs that have regenerated over the 15-years period since the intervention started exhibited basal area, carbon stock, and abundance of chimpanzee food plants at around 75%, 50%, and 77% respectively of the corresponding values observed in the mature woodlands within VLFRs. Furthermore, these forest attributes in the mature woodlands in the VLFRs exceeded 60% of the values found in Gombe mature woodlands. When accounting for factors such as forest age, dispersal mode, and topography, a factor that most impacted above-ground biomass and stem density included the positive influence of village-led patrols. The insights gained from this dissertation can provide valuable lessons for enhancing community forest management practices in similar tropical contexts, critical for increasing habitat quality for wildlife, improving landscape-scale connectivity, and contributing to climate change mitigation.
  • Thumbnail Image
    Item
    The Socioecology of Chimpanzee Foraging and Food-associated Calling Behavior
    (2015-06) O'Bryan, Lisa
    Social-living is complicated. Living in groups can provide greater protection from predators, promote discovery and defense of food sources and improve access to mates. On the other hand, it can increase susceptibility to predators or pathogens and incite competition for resources. Because of these trade-offs, social systems can display high levels of diversity, both on an evolutionary time-scale as well as in response to short-term variation in social and ecological pressures. In this dissertation I investigate the foraging and food-associated calling behavior of chimpanzees (Pan troglodytes) in order to better understand the causes and consequences of grouping behavior. Chimpanzee social groups display high levels of short-term variability in both size and composition. Furthermore, individuals produce specific vocalizations in foraging contexts that are believed to further modulate these parties. Thus, this system provides a prime opportunity to examine the costs and benefits of sociality and how individuals respond to these trade-offs. Using a combination of captive experiments and observational field studies, I examine chimpanzee foraging decisions, the trade-off between foraging and socialization and the social and ecological correlates of food-associated calling behavior. Results from these studies expand current understanding of the foraging and social behavior of chimpanzees and suggest an alternative function for their food-associated rough-grunt vocalization. Furthermore, they highlight the challenges and benefits of social-living and the tactics individuals can employ to manipulate their social landscape.
  • Thumbnail Image
    Item
    Stable Isotope Ecology of Gombe National Park: A Modern Analogue for Fossil Hominins
    (2019-09) Nockerts, Rebecca
    Stable isotopes have revolutionized our understanding of the evolution of the human diet. A key early transition in hominin evolution appears to be the increased consumption of C4 grasses and sedges (and/or animals eating C4 plants) and an adaptation towards more open, seasonal environments. The earliest hominins, Ardipithecus ramidus and Australopithecus anamensis, appear to have had diets reliant on C3 foods, interpreted to be similar to the diets of modern chimpanzees. All later hominins after ~3.5 Mya were mixed C3/C4 feeders, though the extent of C4 consumption varied tremendously, both within and between species. Important limitations remain in using modern referential models to interpret this change in dietary ecology. These include the need for an improved understanding of diet to tissue isotope enrichment and studies of appropriate living populations, in comparable environments, with independently known feeding histories. In order to address those limitations, I conducted a comprehensive analysis of the stable isotope ecology of the chimpanzees (Pan troglodytes schweinfurthii) and baboons (Papio anubis) of Gombe National Park, Tanzania. Both chimpanzees and baboons have been invoked as species with ecological adaptations similar to those of fossil hominins. At Gombe these primates share overlapping ranges in a mixed forest/woodland/grassland habitat similar to those inferred for many hominin localities. I combined observational records of their diets and the isotopic composition of their foods to interpret the isotopic signatures of their hair, nails, bones, and teeth. I then compared these results to previously published isotope studies of other populations of Pan, Papio, and fossil hominins and papionins. I found that Gombe plant isotopes varied across plant growth form and plant part, as well as seasonally and across different habitat types. This variation was reflected, to varying degrees, by differences in the isotopic composition of chimpanzees compared to the baboons. Other aspects of the dietary ecology of the Gombe chimpanzees and baboons are reflected by their tissues, including breastfeeding, variable C4 consumption, and differences in meat and insect consumption. These results indicate that even the earliest known hominins consumed substantially more C4 food resources than any known chimpanzee population, and more than many forest-living baboon populations.