Wright E.,Max Planck Institute for Evolutionary Anthropology |
Grueter C.C.,University of Western Australia |
Seiler N.,Max Planck Institute for Evolutionary Anthropology |
Abavandimwe D.,Karisoke Research Center |
And 3 more authors.
American Journal of Physical Anthropology | Year: 2015
Objective Here, we compare food availability and relate this to differences in energy intake rates, time spent feeding, and daily travel distance of gorillas in the two populations. Comparative intraspecific studies investigating spatiotemporal variation in food availability can help us understand the complex relationships between ecology, behavior, and life history in primates and are relevant to understanding hominin evolution. Differences in several variables have been documented between the two mountain gorilla populations in the Virunga Massif and Bwindi Impenetrable National Park, but few direct comparisons that link ecological conditions to feeding behavior have been made. Materials and Methods Using similar data collection protocols we conducted vegetation sampling and nutritional analysis on important foods to estimate food availability. Detailed observations of feeding behavior were used to compute energy intake rates and daily travel distance was estimated through GPS readings. Results Food availability was overall lower and had greater temporal variability in Bwindi than in the Virungas. Energy intake rates and time spent feeding were similar in both populations, but energy intake rates were significantly higher in Bwindi during the period of high fruit consumption. Daily travel distances were significantly shorter in the Virungas. Conclusions Overall, despite the differences in food availability, we did not find large differences in the energetics of gorillas in the two populations, although further work is needed to more precisely quantify energy expenditure and energy balance. These results emphasize that even species with high food availability can exhibit behavioral and energetic responses to variable ecological conditions, which are likely to affect growth, reproduction, and survival. Am J Phys Anthropol 158:487-500, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc. Source
Seburanga J.L.,College of Science and Technology, University of Rwanda |
Bizuru E.,College of Science and Technology, University of Rwanda |
Mwavu E.N.,Makerere University |
Kampungu K.G.,Beijing Forestry University |
And 4 more authors.
Environmental Management | Year: 2016
Risk-assessment methods are useful in collecting data that can help decision making to prevent the introduction of new species that have the potential of invading as well as in management of established taxa. Not only the complexity and unaffordability of available pre-introduction risk-assessment models make them rarely or inconsistently applied in the least-developed countries, but also there is lack of tools to assess the status of already introduced plant species. In this study, an affordable and rapid method of assessment of invasiveness among introduced plant species was developed and tested in Rwanda. This method defines three invasion stages (potential, effective, and suppressive invaders) and four levels of risk assessment: post-introduction assessment of species inherent invasive potential (Level1), post-establishment assessment of species capacity of regeneration (Level 2), post-naturalization assessment of species range of occurrence and ability for long-distance dispersal (Level 3), and post-naturalization assessment of species ability to outcompete other plants in the community and transform the landscape (Level 4). A review of invasive species in Rwanda was developed through desk review, examination of herbarium records, and vegetation surveys. This method should be applicable in other countries that lack the means for a more conventional scientific investigation or under any circumstance where a quick and inexpensive assessment is needed. The method could be useful to environmental managers for timely intervention with strategies specific to different stages of invasion (post-introduction, post-establishment, or post-naturalization) and allocate resources accordingly. © 2015, Springer Science+Business Media New York. Source
Seburanga J.L.,National University of Rwanda |
Seburanga J.L.,Beijing Forestry University |
Kaplin B.A.,Antioch University New England |
Zhang Q.-X.,Beijing Forestry University |
And 2 more authors.
Urban Forestry and Urban Greening | Year: 2014
According to the national policy, overall forest and agroforestry cover in Rwanda is to increase up to 30% land cover by 2020. On the other hand, demographic data reveal that Rwanda's urban areas are among the fastest-growing on the continent. Unfortunately, there is only little information of the effects of such a rapid urbanization on tree cover and green space structure, knowing that data on urban plant assemblages in the country are rather rare. The paper discusses developments in Kigali's green spaces with regard to its rapid rate of expansion. An integrated approach of research, combining results from interview sessions, desk-based investigations, walk-over and vegetation surveys, and photogrammetric analyses of remotely acquired imagery was applied. The findings suggest that the city green space network consists of plant assemblages largely dominated by alien species (75%). Tree cover fraction averaged at around 10-35%. No significant difference was observed between field-drawn and photogrammetric-based fraction of tree cover estimates; making the later a quick but cheap tool for rapid tree cover evaluation. Cultivated forests, urban woodlots and domestic garden tree stands are far the most dominant types of green spaces in terms of coverage of city surface area. Street tree communities and institutional gardens appear to be the most intensively designed green space layouts. Both distribution and species composition in domestic gardens were socioeconomic-driven. For instance, palm trees were characteristic of fortunate quarters while fruitbearing ornamental such as Psidium guajava and Persea americana were common within scattered and informal settlements. Markhamia lutea, Erythina abyssinica, Euphorbia candelabrum, Phoenix reclinata and Acacia sieberiana are among native taxa that thrive to keep a place in the city. Euphorbia tirucalli, a native tree that is widespread in home compound fences within informal settlements, is significantly declining as modern housing expands and concrete-based fences replace live enclosures. © 2013 Elsevier GmbH. Source
Plebani M.,University of Zurich |
Imanizabayo O.,Karisoke Research Center |
Hansen D.M.,University of Zurich |
Armbruster W.S.,University of Portsmouth |
And 3 more authors.
Journal of Tropical Ecology | Year: 2015
Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination. We measured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences had motile bracts with mean angles varying from ∼50° at 00h00 to ∼90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bract motility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bees. Copyright © 2014 Cambridge University Press. Source
Grueter C.C.,Max Planck Institute for Evolutionary Anthropology |
Grueter C.C.,Karisoke Research Center |
Grueter C.C.,University of Western Australia |
Deschner T.,Max Planck Institute for Evolutionary Anthropology |
And 3 more authors.
Physiology and Behavior | Year: 2014
Maintaining a balanced energy budget is important for survival and reproduction, but measuring energy balance in wild animals has been fraught with difficulties. Female mountain gorillas are interesting subjects to examine environmental correlates of energy balance because their diet is primarily herbaceous vegetation, their food supply shows little seasonal variation and is abundant, yet they live in cooler, high-altitude habitats that may bring about energetic challenges. Social and reproductive parameters may also influence energy balance. Urinary C-peptide (UCP) has emerged as a valuable non-invasive biomarker of energy balance in primates. Here we use this method to investigate factors influencing energy balance in mountain gorillas of the Virunga Volcanoes, Rwanda. We examined a range of socioecological variables on energy balance in adult females in three groups monitored by the Karisoke Research Center over nine months. Three variables had significant effects on UCP levels: habitat (highest levels in the bamboo zone), season (highest levels in November during peak of the bamboo shoot availability) and day time (gradually increasing from early morning to early afternoon). There was no significant effect of reproductive state and dominance rank. Our study indicates that even in species that inhabit an area with a seemingly steady food supply, ecological variability can have pronounced effects on female energy balance. © 2014 Elsevier Inc. Source