The habits and habitats of small rodents in the Congo River catchment region of Zambia and Tanzania

Zoologica Africana 2 (1): 111-12

Annotated check-list of plants occuring in lake Manyara National Park

Volume: 2

Museum DNA reveals the demographic history of the endangered Seychelles warbler

The importance of evolutionary conservation – how understanding evolutionary forces can help guide conservation decisions – is widely recognized. However, the historical demography of many endangered species is unknown, despite the fact that this can have important implications for contemporary ecological processes and for extinction risk. Here, we reconstruct the population history of the Seychelles warbler (Acrocephalus sechellensis) – an ecological model species. By the 1960s, this species was on the brink of extinction, but its previous history is unknown. We used DNA samples from contemporary and museum specimens spanning 140 years to reconstruct bottleneck history. We found a 25% reduction in genetic diversity between museum and contemporary populations, and strong genetic structure. Simulations indicate that the Seychelles warbler was bottlenecked from a large population, with an ancestral Ne of several thousands falling to <50 within the last century. Such a rapid decline, due to anthropogenic factors, has important implications for extinction risk in the Seychelles warbler, and our results will inform conservation practices. Reconstructing the population history of this species also allows us to better understand patterns of genetic diversity, inbreeding and promiscuity in the contemporary populations. Our approaches can be applied across species to test ecological hypotheses and inform conservation

Distribution, variation, and systematics of the Seychelles treefrog, Tachycnemis seychellensis (Amphibia: Anura: Hyperoliidae)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73034/1/j.1469-7998.1995.tb02720.x.pd

Effects of mountain gorilla foraging activities on the productivity of their food plant species

Mountain gorillas subsist principally on foliage from the dense herbaceous understorey that is found throughout most of their habitat in the Virunga Volcanoes region. Their foraging activities cause considerable structural damage to this vegetation. Those plant species that are quantitatively most important in the gorillas' diet respond to this damage by increasing primary productivity. At a sample of spots at which gorillas had fed, these species showed significantly higher growth rates over a 6-month interval than they did at nearby spots that had not been touched by the gorillas. Stem densities of herbaceous food species at feeding spots increased markedly both in comparison to their original values and to values for the same species at untouched spots. As a result, spots at which gorillas have fed are likely to become very attractive as future feeding spots. It is unlikely that gorillas ‘manage’ their habitat in any specific fashion, largely because they do not have exclusive use of their home ranges. Their activities appear to maintain habitat productivity over the short term, on a time scale relevant to patterns of area revisits by social groups, and may contribute to long term beneficial alterations of regularly used areas, however. Effects of the type reported here may have been an important aspect of the adaptation by gorillas to terrestrial folivory. RÉSUMEÉ Les gorilles de montagne s'alimentent principalement de feuillages dans le sous-bois herbacÉ dense prÉsent presque partout dans leur habitat de la rÉgion des volcans Virunga. Leurs activitÉs alimentaires causent des dommages structurels considÉrables À cette vÉgÉtation. Les plantes des espÈces qui sont quantitativement les plus importants dans le rÉgime du gorille rÉagissent À ces dÉgats en augmentant leur productivitÉ primaire. Aux postes Échantillons oÙ les gorilles se sont nourris, ces espÈces prÉsentent des taux de croissance significantivement supÉrieurs sur un intervalle de six mois, par rapport aux postes voisins qui n'ont pas ÉtÉ touchÉs par les gorilles. Les densitÉs de tiges des espÈces herbacÉes appÉtÉes aux postes de nourrissage augmentent nettement aussi bien en comparaison avec leurs valeurs antÉrieures qu'avec celles de ces měmes espÈces dans des stations non touchÉes. En consÉquence, les postes oÙ les gorilles se sont nourris ont plus de chance de devenir des futurs postes de nourrissage trÈs attractifs. Il est peu probable que les gorilles ‘gÈrent’ leur habitat d'une quelconque faÇon, surtout parce qu'ils n'ont pas l'utilisation exclusive de leur domaine vital. Leurs activitÉs semblent maintenir À court terme la productivitÉ de leur habitat, sur une Échelle de temps comprenant les visites successives de groupes sociaux, et peuvent contribuer À long terme À des altÉrations bÉnÉfiques pour ces zones rÉguliÉrement frÉquentÉes. Des effets du type rapportÉ ici peuvent avoir ÉtÉ un ÉlÉment important de l'adaptation des gorilles À la folivorie terrestre.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75171/1/j.1365-2028.1987.tb01102.x.pd

Ecology and co-existence of two endemic day gecko (Phelsuma) species in Seychelles native palm forest

In island ecosystems, reptiles play diverse ecological roles as a result of niche broadening, which increases potential niche overlap between species. Ecological niche partitioning is a means of reducing direct competition between coexisting species and differences in habitat use among island gecko species have been suggested as a by-product of specialization to feeding on certain resources. Here, we examine modes and drivers of niche partitioning of two endemic species of Phelsuma gecko (Phelsuma sundbergi and Phelsuma astriata) in relict native palm forest in the Seychelles to further understanding of congeneric reptile co-existence in native habitats. Phelsuma abundance, microhabitat use and habitat composition were quantified in different macrohabitat types. P. sundbergi showed a clear preference for habitat dominated by the coco de mer palm, Lodoicea maldivica and a strong association with male individuals of this dioecious species. P. astriata density increased significantly with arboreal biodiversity but did not display a relationship with a specific tree type. High levels of resource segregation were determined along the microhabitat axis, based on differential tree preference. Our results suggest that P. sundbergi and P. astriata may have evolved to co-exist in this habitat type through partitioning of microhabitat as members of a divergent specialist/generalist assemblage determined by consumption of L. maldivica pollen by P. sundbergi. Our findings concur with the hypothesis that differences in habitat use among island reptiles are a by-product of trophic specialization and support the conservation of native habitat for maintenance of reptile diversity

The challenges of long-term invasive mammal management: lessons from the UK

We consider the motivations, strategies, and costs involved in invasive mammal management undertaken in the UK. Widespread established invasive mammals require long‐term management to limit damage or spread, but ongoing management is costly and complex. Long‐term management is most effective where it is applied at a landscape scale, but this requires overarching co‐ordination between multiple stakeholders. Five challenges for successful long‐term management of invasive mammal species are identified as follows: defining landscape‐scale strategies, management co‐ordination, stakeholder and community engagement, sustainable funding, and evidence requirements. We make recommendations on the supportive infrastructure needed for effective landscape‐scale management of invasive mammals to fulfil long‐term conservation aims, as follows. 1. There is a need for evidence‐based Invasive Species Action Plans to provide strategy for the long‐term ongoing management of prioritised species at appropriate scales. 2. Where possible, multispecies approaches to invasive species management should be adopted. 3. Trusted leadership should be identified to take ownership of Action Plans and provide an overarching co‐ordination to bring individuals, organisations, and funders together. 4. Support for a centralised hub for training, data, and knowledge flows will greatly improve scientific outcomes through a searchable evidence base, and via best practice and knowledge sharing

Spatial Guilds in the Serengeti Food Web Revealed by a Bayesian Group Model

Food webs, networks of feeding relationships among organisms, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. Despite long-standing interest in the compartmental structure of food webs, past network analyses of food webs have been constrained by a standard definition of compartments, or modules, that requires many links within compartments and few links between them. Empirical analyses have been further limited by low-resolution data for primary producers. In this paper, we present a Bayesian computational method for identifying group structure in food webs using a flexible definition of a group that can describe both functional roles and standard compartments. The Serengeti ecosystem provides an opportunity to examine structure in a newly compiled food web that includes species-level resolution among plants, allowing us to address whether groups in the food web correspond to tightly-connected compartments or functional groups, and whether network structure reflects spatial or trophic organization, or a combination of the two. We have compiled the major mammalian and plant components of the Serengeti food web from published literature, and we infer its group structure using our method. We find that network structure corresponds to spatially distinct plant groups coupled at higher trophic levels by groups of herbivores, which are in turn coupled by carnivore groups. Thus the group structure of the Serengeti web represents a mixture of trophic guild structure and spatial patterns, in contrast to the standard compartments typically identified in ecological networks. From data consisting only of nodes and links, the group structure that emerges supports recent ideas on spatial coupling and energy channels in ecosystems that have been proposed as important for persistence.Comment: 28 pages, 6 figures (+ 3 supporting), 2 tables (+ 4 supporting