Mathias W. Tobler
Botanical Research Institute of Texas
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Featured researches published by Mathias W. Tobler.
Journal of Tropical Ecology | 2009
Mathias W. Tobler; Samia E. Carrillo-Percastegui; George V. N. Powell
We studied the habitat use, activity patterns and use of mineral licks by five species of Amazonian ungulate using data from four 60-d camera trap surveys at two different sites in the lowland rain forest of Madre de Dios, Peru. Camera traps were set out in two regular grids with 40 and 43 camera stations covering an area of 50 and 65 km 2 , as well as at five mineral licks. Using occupancy analysis we tested the hypothesis that species are spatially separated. The results showed that the grey brocket deer (Mazama gouazoubira) occurred almost exclusively in terra firme forests, and that the white-lipped peccary (Tayassu pecan) used floodplain forest more frequently during some surveys. All other species showed no habitat preference and we did not find any spatial avoidance of species. The white-lipped peccary, the collared peccary (Pecari tajacu) as well as the grey brocket deer were strictly diurnal while the lowland tapir (Tapirus terrestris) was nocturnal. The red brocket deer (Mazama americana) was active day and night. The tapir was the species with the highest number of visits to mineral licks (average 52.8 visits per 100 d) followed by the white-lipped peccary (average 16.1 visits per 100 d) and the red brocket deer (average 17.1 visits per 100 d). The collared peccary was only recorded on three occasions and the grey brocket deer was never seen at a lick. Our results suggest that resource partitioning takes place mainly at the diet level and less at a spatial level; however, differences in small-scale habitat use are still possible.
Biodiversity and Conservation | 2007
Mathias W. Tobler; Euridice Honorio; John Janovec; Carlos Reynel
We evaluated the usefulness of herbarium collection databases for assessing patterns of species diversity and distribution based on a dataset from the flowering plant families Moraceae and Myristicaceae from the Peruvian Amazon. For Moraceae, a total of 3523 collections were used representing 134 species. The Myristicaceae were represented by 2113 collections of 46 species. We evaluated the distribution of collections based on 252 grid cells (0.5° size) covering all lowland rainforest in the Peruvian Amazon. We found that collections were concentrated in a few cells and that species diversity clearly increases in relation to collection density. Moraceae were collected in only 45% and Myristicaceae in only 31% of the 252 grid cells. Fifty percent of the collections came from just six and three cells, respectively. Most species were represented by only a small number of collections and collected only in a few grid cells, meaning a few widespread common species tend to dominate the collection records. Not surprisingly, most collections were made close to towns and transport routes. We evaluated the usefulness of rarefaction curves and diversity estimators for comparing diversity between regions. These techniques seem to be of little use for botanical collections due to violations of underlying assumptions. Problems such as accuracy of geographic and taxonomic data and strong bias in the spatial representation of the whole dataset are important to consider when basing conservation analysis, planning, and decision-making on seemingly large databases of biodiversity collections and are discussed in detail.
BMC Evolutionary Biology | 2010
Benoit de Thoisy; Anders Gonçalves da Silva; Manuel Ruiz-García; Andrés Tapia; Oswaldo Ramirez; Margarita Arana; Viviana Quse; César Paz-y-Miño; Mathias W. Tobler; Carlos A. Pedraza; Anne Lavergne
BackgroundUnderstanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae) is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations.ResultsSeparate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque) paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i) a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii) that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum.ConclusionsThis study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill, and role of the Amazon river, have similarly shaped the history of other taxa. Nevertheless further work with additional samples and loci is needed to improve our initial assessment. From a conservation perspective, we did not find a correspondence between genetic structure in lowland tapir and ecogeographic regions proposed to define conservation priorities in the Neotropics. This discrepancy sheds doubt into this schemes ability to generate effective conservation planning for vagile species.
Annals of The Entomological Society of America | 2011
Igor I. Ignatov; John Janovec; Pedro Centeno; Mathias W. Tobler; Juan Grados; Gerardo Lamas; Ian J. Kitching
ABSTRACT The adult sphingid communities of three sites in southeastern Peru representative of the moist tropical forest of the lowland Amazon, the pluvial tropical forest of the upper Amazon and Andean foothills, and the montane cloud forest of the eastern slopes of the Andes were sampled during 2004–2006 by using mercury vapor light traps. In total, 119 species of Sphingidae were documented. Species diversity was highest in the upper Amazon and Andean foothills, with 94 species (21 genera), followed by 80 species (21 genera) in the Amazonian lowlands, and 43 species (17 genera) in the montane cloud forest. The greatest number of endemics (22) was registered at the upper AmazonAndean foothills site. The montane cloud forest site was characterized by the highest relative percentage of endemic species. The species assemblages of the lowland Amazon and the Andean foothills were more similar in composition to each other than to the montane assemblage. All three assemblages proved to be more distinctive than expected based on the proximity of the sampled sites and seemingly good flight capabilities of sphingid moths. This was reflected by the endemics accounting for nearly 40% of the total species pool. By contrast, cosmopolitans numbered only 26 species, or 22% of the total assemblage. We hypothesize that the composition and distribution of sphingid species along this elevational gradient may reflect floristic similarities and differences between the study sites and the extent to which different species are adapted to cope with certain environmental conditions, such as temperature and air humidity.
Biological Conservation | 2013
Mathias W. Tobler; George V. N. Powell
Biological Conservation | 2013
Mathias W. Tobler; Samia E. Carrillo-Percastegui; Alfonso Zúñiga Hartley; George V. N. Powell
Journal of Applied Ecology | 2015
Mathias W. Tobler; Alfonso Zúñiga Hartley; Samia E. Carrillo-Percastegui; George V. N. Powell
Wetlands | 2012
J. Ethan Householder; John Janovec; Mathias W. Tobler; Susan E. Page; Outi Lähteenoja
Journal of Tropical Ecology | 2009
Mathias W. Tobler
SIDA, contributions to botany. | 2006
Fernando H Cornejo Valverde; John Janovec; Mathias W. Tobler