scholarly journals Small mammal diversity along two neighboring Bornean mountains

Author(s):  
Melissa T. R. Hawkins ◽  
Miguel Camacho-Sanchez ◽  
Fred Tuh Yit Yuh ◽  
Jesus E Maldonado ◽  
Jennifer A Leonard

Biodiversity across elevational gradients generally follows patterns, the evolutionary origins of which are debated. We trapped small non-volant mammals across an elevational gradient on Mount (Mt.) Kinabalu (4,101 m) and Mt. Tambuyukon (2,579 m), two neighboring mountains in Borneo, Malaysia. We also included visual records and camera trap data from Mt. Tambuyukon. On Mt. Tambuyukon we trapped a total of 299 individuals from 23 species in 6,187 trap nights (4.8% success rate). For Mt. Kinabalu we trapped a total 213 animals from 19 species, in 2,044 trap nights, a 10.4% success rate. We documented the highest diversity in the low elevations for both mountains, unlike previous less complete surveys which supported a mid-elevation diversity bulge on Mt. Kinabalu. Species richness decreased gradually towards the highlands to a more even community with different species (high turnover), less rich but with the highest levels of endemism. These patterns suggest that an interplay of topography and climatic history of the region were drivers of the diversity gradient, in addition to standing climatic and spatial hypothesis.

2018 ◽  
Author(s):  
Melissa T. R. Hawkins ◽  
Miguel Camacho-Sanchez ◽  
Fred Tuh Yit Yuh ◽  
Jesus E Maldonado ◽  
Jennifer A Leonard

Biodiversity across elevational gradients generally follows patterns, the evolutionary origins of which are debated. We trapped small non-volant mammals across an elevational gradient on Mount (Mt.) Kinabalu (4,101 m) and Mt. Tambuyukon (2,579 m), two neighboring mountains in Borneo, Malaysia. We also included visual records and camera trap data from Mt. Tambuyukon. On Mt. Tambuyukon we trapped a total of 299 individuals from 23 species in 6,187 trap nights (4.8% success rate). For Mt. Kinabalu we trapped a total 213 animals from 19 species, in 2,044 trap nights, a 10.4% success rate. We documented the highest diversity in the low elevations for both mountains, unlike previous less complete surveys which supported a mid-elevation diversity bulge on Mt. Kinabalu. Species richness decreased gradually towards the highlands to a more even community with different species (high turnover), less rich but with the highest levels of endemism. These patterns suggest that an interplay of topography and climatic history of the region were drivers of the diversity gradient, in addition to standing climatic and spatial hypothesis.


1999 ◽  
Vol 15 (5) ◽  
pp. 689-694 ◽  
Author(s):  
Jon C. Lovett

Observed variation in species richness on ecological gradients and between regions has attracted several different explanations. Climatic factors, such as energy availability, precipitation and mean annual temperature, are frequently cited to explain differences in species richness (Wright et al. 1993). The relative amount of variation in these variables may be of importance as well as absolute values (Stevens 1989, 1992). Alternatively, the history of colonization and extirpation have been used to explain regional variation in diversity (Guo et al. 1998; Latham & Ricklefs 1993a, b). Area is an important factor, for example on an elevational gradient the tops of mountains are not only cooler than the bottoms, but they are also much smaller (Rahbek 1997).


2013 ◽  
Vol 280 (1766) ◽  
pp. 20131109 ◽  
Author(s):  
Daniel P. Scantlebury

The evolutionary origins of Madagascar's biodiversity remain mysterious despite the fact that relative to land area, there is no other place with consistently high levels of species richness and endemism across a range of taxonomic levels. Most efforts to explain diversification on the island have focused on geographical models of speciation, but recent studies have begun to address the island's accumulation of species through time, although with conflicting results. Prevailing hypotheses for diversification on the island involve either constant diversification rates or scenarios where rates decline through time. Using relative-time-calibrated phylogenies for seven endemic vertebrate clades and a model-fitting framework, I find evidence that diversification rates have declined through time on Madagascar. I show that diversification rates have clearly declined throughout the history of each clade, and models invoking diversity-dependent reductions to diversification rates best explain the diversification histories for each clade. These results are consistent with the ecological theory of adaptive radiation, and, coupled with ancillary observations about ecomorphological and life-history evolution, strongly suggest that adaptive radiation was an important formative process for one of the most species-rich regions on the Earth. These results cast the Malagasy biota in a new light and provide macroevolutionary justification for conservation initiatives.


2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.


2017 ◽  
Vol 4 ◽  
pp. 1-53 ◽  
Author(s):  
Paul Murphey ◽  
K.E. Townsend ◽  
Anthony Friscia ◽  
James Westgate ◽  
Emmett Evanoff ◽  
...  

The Bridger Formation is restricted to the Green River Basin in southwest Wyoming, and the Uinta and Duchesne River Formations are located in the Uinta Basin in Utah. These three rock units and their diverse fossil assemblages are of great scientific importance and historic interest to vertebrate paleontologists. Notably, they are also the stratotypes from oldest to youngest for the three middle Eocene North American Land Mammal Ages—the Bridgerian, Uintan, and Duchesnean. The fossils and sediments of these formations provide a critically important record of biotic, environmental, and climatic history spanning approximately 10 million years (49 to 39 Ma). This article provides a detailed field excursion through portions of the Green River and Uinta Basins that focuses on locations of geologic, paleontologic, and historical interest. In support of the field excursion, we also provide a review of current knowledge of these formations with emphasis on lithostratigraphy, biochronology, depositional, and paleoenvironmental history, and the history of scientific exploration.


2020 ◽  
Vol 35 (8) ◽  
pp. 1046-1056
Author(s):  
Luisa Patiño ◽  
Maria Isabel Velez ◽  
Marion Weber ◽  
César A. Velásquez‐r ◽  
Santiago David ◽  
...  

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yang Mi ◽  
Pengfei Qu ◽  
Na Guo ◽  
Ruimiao Bai ◽  
Jiayi Gao ◽  
...  

Abstract Background For most women who have had a previous cesarean section, vaginal birth after cesarean section (VBAC) is a reasonable and safe choice, but which will increase the risk of adverse outcomes such as uterine rupture. In order to reduce the risk, we evaluated the factors that may affect VBAC and and established a model for predicting the success rate of trial of the labor after cesarean section (TOLAC). Methods All patients who gave birth at Northwest Women’s and Children’s Hospital from January 2016 to December 2018, had a history of cesarean section and voluntarily chose the TOLAC were recruited. Among them, 80% of the population was randomly assigned to the training set, while the remaining 20% were assigned to the external validation set. In the training set, univariate and multivariate logistic regression models were used to identify indicators related to successful TOLAC. A nomogram was constructed based on the results of multiple logistic regression analysis, and the selected variables included in the nomogram were used to predict the probability of successfully obtaining TOLAC. The area under the receiver operating characteristic curve was used to judge the predictive ability of the model. Results A total of 778 pregnant women were included in this study. Among them, 595 (76.48%) successfully underwent TOLAC, whereas 183 (23.52%) failed and switched to cesarean section. In multi-factor logistic regression, parity = 1, pre-pregnancy BMI < 24 kg/m2, cervical score ≥ 5, a history of previous vaginal delivery and neonatal birthweight < 3300 g were associated with the success of TOLAC. The area under the receiver operating characteristic curve in the prediction and validation models was 0.815 (95% CI: 0.762–0.854) and 0.730 (95% CI: 0.652–0.808), respectively, indicating that the nomogram prediction model had medium discriminative power. Conclusion The TOLAC was useful to reducing the cesarean section rate. Being primiparous, not overweight or obese, having a cervical score ≥ 5, a history of previous vaginal delivery or neonatal birthweight < 3300 g were protective indicators. In this study, the validated model had an approving predictive ability.


2006 ◽  
Vol 23 (3-4) ◽  
pp. ii-ii

The International Colour Vision Society awarded the 2005 Verriest Medal to John D. Mollon, Professor of Visual Neuroscience at the University of Cambridge, UK. This award is bestowed by the Society to honor long-term contributions to the field of color vision. If the field of color vision were itself a rainbow, then Professor Mollon's contributions cover nearly its full spectrum, including the isolation and elucidation of basic chromatic coding mechanisms and the constraints that they impose on human (and more generally primate) visual performance, the genetic basis of spectral coding mechanisms, the ecological influences on and evolutionary origins of chromatic discrimination. He has been instrumental in the design of several new color vision tests and has extensively exploited abnormal models, both congenital and acquired, to further our understanding of normal mechanisms. He is especially appreciated for his keen and profound sense of the history of science, in particular with respect to the field of color vision. He has been a member of the society for over 25 years and is currently serving on its board of directors. He organized the 2001 ICVS meeting in Cambridge, celebrating the bicentennial of Thomas Young's lecture on color vision.


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