Schrey A.W.,University of South Florida |
Grispo M.,University of South Florida |
Awad M.,University of South Florida |
Cook M.B.,University of South Florida |
And 18 more authors.
Molecular Ecology | Year: 2011
Introduced species offer unique opportunities to study evolution in new environments, and some provide opportunities for understanding the mechanisms underlying macroecological patterns. We sought to determine how introduction history impacted genetic diversity and differentiation of the house sparrow (Passer domesticus), one of the most broadly distributed bird species. We screened eight microsatellite loci in 316 individuals from 16 locations in the native and introduced ranges. Significant population structure occurred between native than introduced house sparrows. Introduced house sparrows were distinguished into one North American group and a highly differentiated Kenyan group. Genetic differentiation estimates identified a high magnitude of differentiation between Kenya and all other populations, but demonstrated that European and North American samples were differentiated too. Our results support previous claims that introduced North American populations likely had few source populations, and indicate house sparrows established populations after introduction. Genetic diversity also differed among native, introduced North American, and Kenyan populations with Kenyan birds being least diverse. In some cases, house sparrow populations appeared to maintain or recover genetic diversity relatively rapidly after range expansion (<50 years; Mexico and Panama), but in others (Kenya) the effect of introduction persisted over the same period. In both native and introduced populations, genetic diversity exhibited large-scale geographic patterns, increasing towards the equator. Such patterns of genetic diversity are concordant with two previously described models of genetic diversity, the latitudinal model and the species diversity model. © 2011 Blackwell Publishing Ltd.
van Geel B.,University of Amsterdam |
Gelorini V.,Ghent University |
Lyaruu A.,University of Amsterdam |
Aptroot A.,Adviesbureau voor Bryologie en Lichenologie |
And 5 more authors.
Review of Palaeobotany and Palynology | Year: 2011
Fossil fungal spores and other non-pollen palynomorphs (NPPs) are powerful environmental proxies in European palaeoecological and archaeological contexts. However, their application on other continents, and particularly in the tropics, is hampered by uncertain equivalence with morphologically similar taxa in Europe, and incomplete knowledge of their ecology in the new local contexts. Here we use fossil NPP assemblages in a 25,000-year sediment record from Lake Challa, a steep-sided crater lake near Mt. Kilimanjaro in southeastern Kenya, to assess NPP diversity in a tropical-African context and the equivalence of African taxa with their European counterparts. We recovered a total of 65 well-defined NPP types, of which 61 are fungal spores, and 42 could be linked to known taxa. We provide diagnoses and illustrations of 61 recovered taxa, 58 of which have not been documented before. Using the Challa pollen record of past regional vegetation dynamics and two independent proxies of past temperature and rainfall, we also assessed the association of individual fungal taxa with particular species and biomes of tropical-African vegetation, and with the history of regional climate change. We often found strong correspondence between the stratigraphic distribution of individual fungal spore taxa and the occurrence of specific vegetation types. Changing climate conditions appear to have had a strong impact on the ability of fungi to play a role in the decomposition of dead plants. For fungal spore assemblages, the most prominent change in regional palaeoenvironments over the past 25,000. years occurred at the start of the wet early Holocene, following Younger Dryas drought. Epicoccum purpurascens is common in the Glacial and Late-Glacial parts of the sequence, but shows a strong decline during the early Holocene. Coniochaeta cf. ligniaria occurs throughout the record but shows dramatic fluctuations that appear to relate to major changes in humidity. Correlation between fungal abundance and humidity is also observed in taxa for which the Challa region provided suitable habitat from ca. 16,500. cal.yr. BP (e.g., Curvularia) or from the Late-Glacial to Holocene transition (e.g., Tetraploa aristata, Dictyoarthrinium cf. sacchari, cf. Byssothecium, types HdV-1032 and HdV-1033, cf. Alternaria, cf. Brachysporium, cf. Helminthosporium, Spegazzinia tessarthra and cf. Lasiodiplodia theobromae). Many of these taxa did not occur, or were rare, during both wet and dry phases of the Glacial period, suggesting an additional temperature effect on their occurrence in tropical African environments. A possibly dominant role of temperature is revealed in the stratigraphic distribution of Acrodictys, which appears at the onset of deglacial climate warming ca. 17,500. cal.yr. BP and remains common throughout both wet and dry phases of the Holocene. Spores of the dung-inhabiting fungus Sporormiella occur throughout the 25,000-year record without notable fluctuations, suggesting little changes in the overall population density of large herbivores in the region. © 2011 Elsevier B.V.
Esona M.D.,Centers for Disease Control and Prevention |
Mijatovic-Rustempasic S.,Centers for Disease Control and Prevention |
Conrardy C.,Centers for Disease Control and Prevention |
Tong S.,Centers for Disease Control and Prevention |
And 8 more authors.
Emerging Infectious Diseases | Year: 2010
Bats are known reservoirs of viral zoonoses. We report genetic characterization of a bat rotavirus (Bat/KE4852/07) detected in the feces of a straw-colored fruit bat (Eidolon helvum). Six bat rotavirus genes (viral protein [VP] 2, VP6, VP7, nonstructural protein [NSP] 2, NSP3, and NSP5) shared ancestry with other mammalian rotaviruses but were distantly related. The VP4 gene was nearly identical to that of human P rotavirus strains, and the NSP4 gene was closely related to those of previously described mammalian rotaviruses, including human strains. Analysis of partial sequence of the VP1 gene indicated that it was distinct from cognate genes of other rotaviruses. No sequences were obtained for the VP3 and NSP1 genes of the bat rotavirus. This rotavirus was designated G25-P-I15-R8(provisional)-C8- Mx-Ax-N8-T11-E2-H10. Results suggest that several reassortment events have occurred between human, animal, and bat rotaviruses. Several additional rotavirus strains were detected in bats.
Kosoy M.,Centers for Disease Control and Prevention |
Bai Y.,Centers for Disease Control and Prevention |
Lynch T.,Centers for Disease Control and Prevention |
Kuzmin I.V.,Centers for Disease Control and Prevention |
And 5 more authors.
Emerging Infectious Diseases | Year: 2010
We report the presence and diversity of Bartonella spp. in bats of 13 insectivorous and frugivorous species collected from various locations across Kenya. Bartonella isolates were obtained from 23 Eidolon helvum, 22 Rousettus aegyptiacus, 4 Coleura afra, 7 Triaenops persicus, 1 Hipposideros commersoni, and 49 Miniopterus spp. bats. Sequence analysis of the citrate synthase gene from the obtained isolates showed a wide assortment of Bartonella strains. Phylogenetically, isolates clustered in specific host bat species. All isolates from R. aegyptiacus, C. afra, and T. persicus bats clustered in separate monophyletic groups. In contrast, E. helvum and Miniopterus spp. bats harbored strains that clustered in several groups. Further investigation is needed to determine whether these agents are responsible for human illnesses in the region.
PubMed | Centers for Disease Control and Prevention, Ross University School of Medicine, Kenya Medical Research Institute, Emory University and 2 more.
Type: Journal Article | Journal: PLoS neglected tropical diseases | Year: 2015
Several rodent-associated Bartonella species are human pathogens but little is known about their epidemiology. We trapped rodents and shrews around human habitations at two sites in Kenya (rural Asembo and urban Kibera) to determine the prevalence of Bartonella infection. Bartonella were detected by culture in five of seven host species. In Kibera, 60% of Rattus rattus were positive, as compared to 13% in Asembo. Bartonella were also detected in C. olivieri (7%), Lemniscomys striatus (50%), Mastomys natalensis (43%) and R. norvegicus (50%). Partial sequencing of the citrate synthase (gltA) gene of isolates showed that Kibera strains were similar to reference isolates from Rattus trapped in Asia, America, and Europe, but that most strains from Asembo were less similar. Host species and trapping location were associated with differences in infection status but there was no evidence of associations between host age or sex and infection status. Acute febrile illness occurs at high incidence in both Asembo and Kibera but the etiology of many of these illnesses is unknown. Bartonella similar to known human pathogens were detected in small mammals at both sites and investigation of the ecological determinants of host infection status and of the public health significance of Bartonella infections at these locations is warranted.
Wei R.,CAS Institute of Botany |
Xiang Q.,CAS Institute of Botany |
Schneider H.,Natural History Museum in London |
Sundue M.A.,University of Vermont |
And 4 more authors.
Journal of Biogeography | Year: 2015
Aim: Gondwanan vicariance, boreotropical migration and long-distance dispersal have been posited as alternative hypotheses explaining the tropical distribution patterns and diversifications in many fern groups. Here, the historical biogeography of Diplazium is reconstructed to evaluate the impact of these biogeographical processes in shaping the modern tropical disjunctions. Location: World-wide with a focus on tropical forest habitats. Methods: Divergence times were estimated by analysing nucleotide sequences of seven plastid DNA regions (atpA, atpB, matK, rbcL, rps4, rps4-trnS and trnL-F) from 123 species of Diplazium and its allied genera, using a Bayesian relaxed clock method and three fossil calibrations. The ancestral areas were reconstructed using the likelihood dispersal-extinction-cladogenesis (DEC) approach. Results: The crown group of Diplazium was estimated to have originated in Eurasia and undergone an initial diversification in the Northern Hemisphere around 41.7 Ma [95% highest posterior density (HPD): 34-49 Ma] during the Eocene. Two disjunct events between the Old and New World were identified: one in subgenus Diplazium around the Eocene-Oligocene boundary (31.2 Ma, 95% HPD: 25-38 Ma), and the other in subgenus Callipteris during the middle Miocene (12.6 Ma, 95% HPD: 15-23 Ma). Furthermore, Palaeotropical disjunctions in subgenus Callipteris are indicative of multiple dispersal events during the Miocene. Main conclusions: The evolutionary history of Diplazium involves a variety of biogeographical scenarios. Early diversification of Diplazium in the Northern Hemisphere during the Eocene corresponds with the migration from Eurasia to North America over land bridges as a member of the boreotropical flora. The current tropical amphi-Pacific disjunctions in subgenus Diplazium can be better explained by the disruption of boreotropical belt, however, long-distance dispersal between Eurasia and tropical America cannot be ruled out. Island-hopping and trans-Pacific dispersals followed by speciation characterize the disjunctions and diversifications of subgenus Callipteris during the Neogene. Gondwanan vicariance is not supported by any of our results. © 2015 John Wiley & Sons Ltd.
An exploratory study on the combined effects of external and internal morphology on load dissipation in primate capitates: Its potential for an understanding of the positional and locomotor repertoire of early hominins
Macho G.A.,Institute Catala Of Paleontologia |
Spears I.R.,University of Teesside |
Leakey M.G.,National Museum of Kenya |
Leakey M.G.,State University of New York at Stony Brook |
And 5 more authors.
Folia Primatologica | Year: 2010
This pilot study explored whether the redirection of stress through trabeculae within morphologically constrained capitates provides information about habitual/positional behaviours unavailable from the study of external morphology alone. To assess this possibility, an experimental finite element approach was taken, whereby no attempt was made to reconstruct the actual magnitudes and loading conditions experienced by the capitates in vivo. Rather, this work addressed fundamental biological questions relating to bone plasticity, i.e. internal versus external bone morphology. The capitates of 7 species with different and - in the case of fossils - inferred locomotor behaviours were selected. Virtual models of capitates were created, scaled to the same size and subjected to the same theoretical load. In the first set of analyses, models were assigned the material properties of bone throughout, whereas in the second set, models were assigned 11 different material properties representing the trabecular architecture derived from high-resolution CT. Species with arboreal behaviours consistently redirected loads towards the ulnar aspect of the capitate when trabeculae were introduced, while terrestrial species, and the bipedal Homo, redirected stress towards the radial side. From these preliminary analyses, it is tentatively concluded that Australopithecus anamensis habitually engaged in arboreal behaviours, whereas Australopithecus afarensis did not. Copyright © 2011 S. Karger AG, Basel.
Zhang L.,CAS Chengdu Institute of Biology |
Rothfels C.J.,University of British Columbia |
Ebihara A.,National Museum of Nature and Science |
Schuettpelz E.,Smithsonian Institution |
And 9 more authors.
Cladistics | Year: 2015
The brake fern genus Pteris belongs to the Pteridaceae subfamily Pteridoideae. It contains 200-250 species distributed on all continents except Antarctica, with its highest species diversity in tropical and subtropical regions. The monophyly of Pteris has long been in question because of its great morphological diversity and because of the controversial relationships of the Australian endemic monospecific genus Platyzoma. The circumscription of the Pteridoideae has likewise been uncertain. Previous studies typically had sparse sampling of Pteris species and related genera and used limited DNA sequence data. In the present study, DNA sequences of six plastid loci of 146 accessions representing 119 species of Pteris (including the type of the genus) and 18 related genera were used to infer a phylogeny using maximum-likelihood, Bayesian-inference and maximum-parsimony methods. Our major results include: (i) the previous uncertain relationships of Platyzoma were due to long-branch attraction; (ii) Afropteris, Neurocallis, Ochropteris and Platyzoma are all embedded within a well-supported Pteris sensu lato; (iii) the traditionally circumscribed Jamesonia is paraphyletic in relation to a monophyletic Eriosorus; (iv) Pteridoideae contains 15 genera: Actiniopteris, Anogramma, Austrogramme, Cerosora, Cosentinia, Eriosorus, Jamesonia, Nephopteris (no molecular data), Onychium, Pityrogramma, Pteris, Pterozonium, Syngramma, Taenitis and Tryonia; and (v) 15 well-supported clades within Pteris are identified, which differ from one another on molecular, morphological and geographical grounds, and represent 15 major evolutionary lineages. © The Willi Hennig Society 2014.
Lanckriet S.,Ghent University |
Rucina S.,National Museum of Kenya |
Frankl A.,Ghent University |
Ritler A.,University of Bern |
And 2 more authors.
Science of the Total Environment | Year: 2015
Vegetation cover changes in African drylands are often thought to result from population growth, social factors and aridification. Here we show that long-term vegetation proxy records can help disentangling these main driving factors. Taking the case of North Ethiopia, we performed an integrated investigation of land cover changes over the last four centuries around the endorheic Lake Ashenge, as derived from pollen analysis and repeat photography complemented with information from historical sources. Pollen and sediment analysis of radiocarbon-dated lake deposits shows a phase of environmental destabilization during the 18th century, after a more stable previous period. This is evidenced by decreases of tree pollen (. Juniperus, Olea, Celtis, Podocarpus <. 5%), increases in Poaceae (>. 40%) and deposition of coarser silt lake sediments (>. 70%). Quantitative analysis of 30 repeated landscape photographs around the lake indicates a gradual decline of the vegetation cover since a relative maximum during the mid-19th Century. Vegetation cover declined sharply between the 1950s and the 1980s, but has since begun to recover. Overall, the data from around Lake Ashenge reveal a nonlinear pattern of deforestation and forest regrowth with several periods of vegetation cover change over the past four centuries. While there is forcing of regional drought and the regional land tenure system, the cyclic changes do not support a simplified focus on aridification or population growth. © 2015 Elsevier B.V.
Martin L.B.,University of South Florida |
Alam J.L.,University of South Florida |
Imboma T.,National Museum of Kenya |
Liebl A.L.,University of South Florida
Oecologia | Year: 2010
Many introduced animals harbor fewer parasites than native ones. This "enemy release" can select for individuals that bias resources away from parasite resistance traits, including immune functions, and towards traits that enhance success in new areas. One vertebrate example that supports this hypothesis involves house sparrows (Passer domesticus) and Eurasian tree sparrows (Passer montanus) introduced to St. Louis, MO, USA, over 150 years ago. Since ca. 1850, house sparrows have colonized most of North America whereas tree sparrows have expanded little from the area of introduction. The more successful house sparrows now exhibit weaker inflammatory responses than the less successful tree sparrows, which supports the possibility that diminished investments in immune defense may have been conducive to the initial colonization by the more successful species. The goal of the present study was to determine whether damped inflammation generally facilitates invasion by comparing inflammatory markers between house sparrows invading Kenya and a native congener. House sparrows arrived in Mombasa, Kenya, about 50 years ago whereas rufous sparrows (Passer ruficinctus) are native but ecologically similar. We predicted that if inflammation mediated invasion success, Kenyan house sparrows would mount weaker inflammatory responses than the native species. Complete Freund's adjuvant (CFA), a strong inflammatory stimulus, increased body mass in house sparrows, a result unprecedented in any other vertebrate. Haptoglobin (Hp), a multi-functional acute phase protein, was elevated by CFA in both species but rufous sparrows maintained more Hp than house sparrows irrespective of treatment. Lysozyme, a broadly effective antimicrobial enzyme, was reduced by CFA in both species, but not differentially so. Corticosterone was unaffected by CFA in either species, but elevated in both relative to free-living individuals. © 2010 Springer-Verlag.