Browsing by Author "Davenport, Tim R. B."

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    Description of A New and Critically Endangered Species of Atheris (Serpentes: Viperidae) From the Southern Highlands of Tanzania, With an Overview of The Country's Tree Viper Fauna
    (2011-12) Menegon, Michele; Davenport, Tim R. B.; Howell, Kim
    A new species of arboreal forest viper (Serpentes: Viperidae: Atheris) from a forest fragment in the Southern Highlands of Tanzania is described and named Atheris matildae sp. nov. The species resembles the forest horned viper, Atheris cer-atophora Werner, by bearing horn-like supraciliary scales but it differs in size, body proportions, scalation, scale ultra-structure, and distribution. Genetic divergence is also assessed and the two species have an estimated divergence time of approximately 2.2 million years. An overview of the genus Atheris in Tanzania, including new distribution data, is pre-sented and the conservation status of the new taxon is discussed
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    The Forgotten ‘Coastal Forests’ of Mtwara, Tanzania: A Biologically Impoverished and Yet Important Ecosystem
    (2009-11) Wegner, Giulia; Howell, Kim; Davenport, Tim R. B.; Burgess, Neil D.
    Biodiversity surveys and the compilation of indigenous knowledge were conducted in eight previously unstudied proposed and already gazetted Forest Reserves of Mtwara Region, south-eastern Tanzania, from April to August of 2005. The results indicate relatively low biodiversity and endemism values in these forests, and high levels of forest disturbance. In most areas the original vegetation has been converted by clearance for cultivation and by fire, and has regenerated into degraded forms of Swahilian/Coastal Mixed Dry Forest, Swahilian/Coastal Brachystegia Forest and floristically impoverished Zambezian-Swahilian Brachystegia Woodland. Some Coastal Forest endemic and threatened species, however, occur in the degraded forest patches, such as east coast akalat Sheppardia gunningi, Reichenow's batis Batis mixta reichenowi, spotted flat-lizard Platysaurus maculatus, woodland toad Mertensophryne micranotis and the shrub Gardenia transvenulosa. The low proportion of endemic and threatened species recorded implies that these forests are of modest biological importance within the context of the Eastern Arc Mountains and Coastal Forests Biodiversity Hotspot. Nevertheless, local inhabitants depend heavily on the long-term
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    Persistence and stability of Eastern Afromontane forests: Evidence from brevicipitid frogs
    (2014-03) Loader, Simon; Ceccarelli, Fadia S.; Menegon, Michele; Howell, Kim; Kassahun, Roman; Mengistu, Abebe A.; Saber, Samy; Gebresenbet, Fikirte; de Sá, Rafael O.; Davenport, Tim R. B.; Larson, Joanna G.; Müller, Hendrik; Wilkinson, Mark; Gower, David
    AimThe persistence and stability of habitats through time are considered predictors of high levels of biodiversity in some environments. Long-term habitat persistence and stability may explain the species-rich, endemic forest fauna and flora of the Eastern Afromontane Biodiversity Region (EABR). Using complementary phylogenetic and biogeographical approaches, we examine evolutionary patterns in EABR brevicipitid frogs. Using these data, we test whether brevicipitid history reflects patterns of long-term forest persistence and/or stability across the EABR.LocationEast Africa.MethodsA dated phylogeny for brevicipitids was constructed using two nuclear and three mitochondrial markers. Alternative diversification models were used to determine signal for constant or varying net diversification rates. Using our dated tree, we identified areas of high phylogenetic diversity (PD), and inferred ancestral areas using likelihood and Bayesian approaches.ResultsBrevicipitids have a long history, with generic diversification among extant lineages pre-dating the Oligocene (> 33 Ma). Ancestral-area reconstructions indicate the presence of brevicipitids in the EABR since the Oligocene, and support a scenario of palaeoendemics surviving in EABR refugia. Ancestral-area reconstructions indicate that the central Eastern Arc Mountains (EAM) formed the initial centre of diversification of forest brevicipitids. Measures of PD show that diversity varies across the EABR but is highest in the EAM. Constant net diversification rate in brevicipitids is a significantly better fit than alternative, rate-variable models.Main conclusionsThe degree of persistence of forest habitats appears to be a contributing factor to the varying levels of diversity across the EABR in brevicipitids (and other organisms). In contrast to the Southern Highlands and Ethiopian Bale Mountains, the EAM stands out as an area that enabled the constant accumulation of brevicipitid species over a long period of time.