Parks, people and pixels: evaluating landscape effects of an East African national park on its surroundings

Landscapes surrounding protected areas, while still containing considerable biodiversity, have rapidly growing human populations and associated agricultural development in most of the developing world that tend to isolate them, potentially reducing their conservation value. Using field studies and multi-temporal Landsat imagery, we examine a forest park, Kibale National Park in western Uganda, its changes over time, and related land cover change in the surrounding landscape. We find Kibale has successfully defended its borders and prevents within-park deforestation and other land incursions, and has maintained tree cover throughout the time period of the study. Outside the park there was a significant increase in tea plantations and continued forest fragmentation and wetland loss. The question of whether the park is a conservation success because of the network of forest fragments and wetlands or in spite of them remains unanswered

What is the predictive power of the colobine protein-to-fiber model and its conservation value?

Predicting variation in animal abundance across time and space has proven very difficult; however, a model exists to predict the biomass of small folivorous primates that has considerable correlative support. This model suggests that the protein-to-fiber ratio of leaves in a habitat can predict folivore biomass. Here we present an experimental test of this protein-to-fiber model to assess if the number of infant monkeys per female and group size can be predicted based on the leaf chemistry of a habitat. We expected regenerating forest in Kibale National Park, Uganda to have leaves with higher concentrations of crude protein and lower concentrations of fiber than old-growth forest trees, and consequently, we expected a greater number of infants per female in the folivorous red colobus (Procolobus rufomitratus) with access to this area. As predicted, regenerating forests did have trees with leaves with high concentrations of protein and low concentrations of fiber, but there was no corresponding change in the demographic structure of red colobus groups. We also tested whether energy was a potential determinant of these parameters, but found no evidence for its importance. Our findings support recent studies that are critical of the protein-to-fiber model, which lead us to question the model’s generality, particularly for conservation and management

Does the presence of elephant dung create hotspots of growth for existing seedlings?

In general, the addition of elephant dung did not increase seedling growth, and only increased the number of leaves in shade-tolerant plants with a large initial number of leaves. Researchers have speculated that the loss of elephants would shift the composition of African forests to slow-growing tree species. However, findings in this study show some slow-growing shade-tolerant plants grew more new leaves with additional nutrient input from elephant dung, a condition that would occur if elephant numbers increase. Forest elephant (Loxodonta cyclotis) populations declined by 62% between 2002 and 2011. The population is now only 10% of what it was historically, and occupies less than 25% of its original range

Primate population dynamics : variation in abundance over space and time

The paper presents longitudinal data documenting changes in primate abundance over 45 years at eight sites in Kibale National Park, Uganda. Findings present a positive conservation message and indicate that the Uganda Wildlife Authority is being effective in managing its biodiversity. However, monitoring of deforestation and continued monitoring and modification of conservation plans are essential. The rapid disappearance of tropical forests, potential impacts of climate change, and increasing threats to wildlife such as bushmeat hunting, make it imperative to understand wildlife population dynamics. With long-lived animals this requires extensive, long-term data, but such data is often lacking.Canada Research Chairs ProgramNatural Science and Engineering Research Council of CanadaFonds Québécois de la Recherché sur la Nature et les TechnologiesNational Geographic Societ

Carbon sequestration and biodiversity following 18 years of active tropical forest restoration

Vast areas of degraded tropical forest, combined with increasing interest in mitigating climate change and conserving biodiversity, demonstrate the potential value of restoring tropical forest. However, there is a lack of long-term studies assessing active management for restoration. Here we investigate Above-Ground Biomass (AGB), forest structure, and biodiversity, before degradation (in old-growth forest), after degradation (in abandoned agricultural savanna grassland), and within a forest that is actively being restored in Kibale National Park, Uganda. In 1995 degraded land in Kibale was protected from fire and replanted with native seedlings (39 species) at a density of 400 seedlings ha-1. Sixty-five plots (50 m × 10 m) were established in restoration areas in 2005 and 50 of these were re-measured in 2013, allowing changes to be assessed over 18 years. Degraded plots have an Above Ground Biomass (AGB) of 5.1 Mg dry mass ha-1, of which 80% is grass. By 2005 AGB of trees ≥10 cm DBH was 9.5 Mg ha-1, increasing to 40.6 Mg ha-1 by 2013, accumulating at a rate of 3.9 Mg ha-1 year-1. A total of 153 planted individuals ha-1 (38%) remained by 2013, contributing 28.9 Mg ha-1 (70%) of total AGB. Eighteen years after restoration, AGB in the plots was 12% of old-growth (419 Mg ha-1). If current accumulation rates continue restoration forest would reach old-growth AGB in a further 96 years. Biodiversity of degraded plots prior to restoration was low with no tree species and 2 seedling species per sample plot (0.05 ha). By 2005 restoration areas had an average of 3 tree and 3 seedling species per sample plot, increasing to 5 tree and 9 seedling species per plot in 2013. However, biodiversity was still significantly lower than old-growth forest, at 8 tree and 16 seedling species in an equivalent area. The results suggest that forest restoration is beneficial for AGB accumulation with planted stems storing the majority of AGB. Changes in biodiversity appear slower; possibly due to low stem turnover. Overall this restoration treatment is an effective means of restoring degraded land in the area, as can be seen from the lack of regeneration in degraded plots, which remain low-AGB and diversity, largely due to the impacts of fire and competition with grasses

Does the presence of elephant dung create hotspots of growth for existing seedlings?

International audienceMegaherbivores play a central role in the evolution and functioning of ecosystems. In tropical forests elephant species are some of the few remaining megaherbivores. Through elephant foraging, nutrients that would be locked in leaves and stems, taking months or years to decay, are quickly liberated for use. In 10 experimental sites in Kibale National Park, Uganda, we set up 10 pairs of plots (4 × 4 m), each pair involved one treatment, elephant dung addition, and one control. After 1 y, we quantified growth (height and leaf number) and survival of young light-demanding (12) and shade-tolerant (19) plant species (439 stems in total). In general, the addition of elephant dung did not increase seedling growth, and it only increased the number of leaves in shade-tolerant plants with a large initial number of leaves. Researchers have speculated that the loss of elephants would shift the composition of African forests to slow-growing tree species. However, this is not supported by our finding that shows some slow-growing shade-tolerant plants grew more new leaves with additional nutrient input from elephant dung, a condition that would occur if elephant numbers increase

Restoration provides hope for faunal recovery : changes in primate abundance over 45 years in Kibale national park, Uganda

This research demonstrates the potential for the management of regenerating forests as an effective conservation tool, and illustrates the importance of conducting and funding long-term monitoring. It is estimated that secondary forests now represent 35% of all remaining tropical forests and the only viable populations of some species are found in degraded forest areas. The Chapman et al. studies (2000; 2010; 2013; 2018) have documented primate population dynamics in old-growth forest, lightly and heavily logged forests, regenerating forests in former pine plantations, and forests planted on abandoned agricultural land. The current study analyzes findings from over 20 years of observations.The Canada Research Chairs ProgramNatural Science and Engineering Research Council of CanadaKyoto Universit

The evolution of fruit colour : phylogeny, abiotic factors and the role of mutualists

The study employs an integrative multivariate approach which successfully examines what drives variation in fruit colour. It used phylogenetically controlled models to estimate the roles of phylogeny, abiotic factors, and dispersal mode on fruit colour variation. The effects of animal selection on fruit colour are often difficult to identify. However, the study findings demonstrate that fruit colour is affected by both animal sensory ecology and abiotic factors. Fruit reflection in the ultraviolet area of the spectrum is strongly correlated with leaf reflectance, but it does not correlate with leaf colour in the visible spectrum, thus emphasizing the role of abiotic factors in determining fruit colour.German Science Foundation grantNSERC CanadaThe CRC progra

Nodule worm infection in humans and wild primates in Uganda: cryptic species in a newly identified region of human transmission.

Soil-transmitted helminths (STHs) are a major health concern in tropical and sub-tropical countries. Oesophagostomum infection is considered endemic to West Africa but has also been identified in Uganda, East Africa, among primates (including humans). However, the taxonomy and ecology of Oesophagostomum in Uganda have not been studied, except for in chimpanzees (Pan troglodytes), which are infected by both O. bifurcum and O. stephanostomum.We studied Oesophagostomum in Uganda in a community of non-human primates that live in close proximity to humans. Prevalence estimates based on microscopy were lower than those based on polymerase chain reaction (PCR), indicating greater sensitivity of PCR. Prevalence varied among host species, with humans and red colobus (Procolobus rufomitratus) infected at lowest prevalence (25% and 41% by PCR, respectively), and chimpanzees, olive baboons (Papio anubis), and l'hoest monkeys (Cercopithecus lhoesti) infected at highest prevalence (100% by PCR in all three species). Phylogenetic regression showed that primates travelling further and in smaller groups are at greatest risk of infection. Molecular phylogenetic analyses revealed three cryptic clades of Oesophagostomum that were not distinguishable based on morphological characteristics of their eggs. Of these, the clade with the greatest host range had not previously been described genetically. This novel clade infects humans, as well as five other species of primates.Multiple cryptic forms of Oesophagostomum circulate in the people and primates of western Uganda, and parasite clades differ in host range and cross-species transmission potential. Our results expand knowledge about human Oesophagostomum infection beyond the West African countries of Togo and Ghana, where the parasite is a known public health concern. Oesophagostomum infection in humans may be common throughout Sub-Saharan Africa, and the transmission of this neglected STH among primates, including zoonotic transmission, may vary among host communities depending on their location and ecology