162 research outputs found

    Fossils of an endangered, endemic, giant dipterocarp species open a historical portal into Borneo's vanishing rainforests

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    Premise: Asia's wet tropical forests face a severe biodiversity crisis, but few fossils record their evolutionary history. We recently discovered in situ cuticles on fossil leaves, attributed to the giant rainforest tree Dryobalanops of the iconic Dipterocarpaceae family, from the Plio-Pleistocene of Brunei Darussalam (northern Borneo). Studying these specimens allowed us to validate the generic identification and delineate affinities to living dipterocarp species. Methods: We compared the leaf cuticles and architecture of these fossil leaves with the seven living Dryobalanops species. Results: The cuticular features shared between the fossils and extant Dryobalanops, including the presence of giant stomata on veins, confirm their generic placement. The leaf characters are identical to those of D. rappa, an IUCN red-listed Endangered, northern Borneo endemic. The D. rappa monodominance at the fossil site, along with Dipterocarpus spp. leaf fossils, indicates a dipterocarp-dominated forest near the mangrove-swamp depocenter, most likely in an adjacent peatland. Conclusions: The Dryobalanops rappa fossils are the first fossil evidence of a living endangered tropical tree species and show how analysis of in situ cuticles can help illuminate the poorly known floristic history of the Asian tropics. This discovery highlights new potential for fossils to inform heritage values and paleoconservation in Southeast Asia

    Phylogenetic classification of the world's tropical forests

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    Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests

    Replication Data for An estimate of the number of tropical tree species.

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    The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa

    From earthquakes to island area: multi‐scale effects upon local diversity

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    Tropical forests occupy small coral atolls to the vast Amazon basin. They occur across bioregions with different geological and climatic history. Differences in area and bioregional history shape species immigration, extinction and diversification. How this effects local diversity is unclear. The Indonesian archipelago hosts thousands of tree species whose coexistence should depend upon these factors. Using a novel dataset of 215 Indonesian forest plots, across fifteen islands ranging in area from 120 to 785 000 km 2 , we apply Gaussian mixed effects models to examine the simultaneous effects of environment, earthquake proximity, island area and bioregion upon tree diversity for trees ≥ 10 cm diameter at breast height. We find that tree diversity declines with precipitation seasonality and increases with island area. Accounting for the effects of environment and island area we show that the westernmost bioregion Sunda has greater local diversity than Wallacea, which in turn has greater local diversity than easternmost Sahul. However, when the model includes geological activity (here proximity to major earthquakes), bioregion differences are reduced. Overall, results indicate that multi‐scale, current and historic effects dictate tree diversity. These multi‐scale drivers should not be ignored when studying biodiversity gradients and their impacts upon ecosystem function

    The use of species-area relationships to partition the effects of hunting and deforestation on bird extirpations in a fragmented landscape

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    Article first published online: 22 DEC 2014Aim: Forest fragmentation is often accompanied by an increase in hunting intensity. Both factors are known drivers of species extirpations, but understanding of their independent effects is poor. Our goal was to partition the effects of hunting and fragmentation on bird species extirpations and to identify bird traits that make species more vulnerable to these two stressors. Location: Menglun, Yunnan, SW China Methods: We studied the landscape within 10 km radius of Menglun town, where forests have become highly fragmented by monoculture rubber plantations. We compiled data on birds recorded between 1954 and 1983 before forest loss and compared it with a checklist prepared between 2011 and 2014. We used countryside and matrix-calibrated species–area models (SAMs) to estimate the observed slope of forest bird extirpations in Menglun and compared it with the slope expected in the absence of hunting. We also investigated six ecological traits to determine those that best explained bird extirpation probability (EP). Results: We found that 34% of the bird fauna had been extirpated from the study landscape, and the estimated slopes of countryside and matrix-calibrated SAMs for forest birds were around 1.4 and 1.7 times higher, respectively, than the 0.35 expected without hunting. Bird EP was strongly associated with size, and understorey insectivores that are known to be susceptible to fragmentation were less susceptible to hunting than frugivores. Given evidence of past and present hunting activity in the area, and the lack of support for alternative explanations, we suggest that hunting increased forest bird extirpations by around 1.3- to 1.6-fold. Conclusions: This study highlights the importance of using species–area relationships to separate area effects from the impacts of hunting. Our results suggest that hunting substantially increases species extirpations in tropical fragmented landscapes and conservation interventions that only target deforestation will therefore be inadequate.Rachakonda Sreekar, Guohualing Huang, Jiang-Bo Zhao, Bonifacio O. Pasion, Mika Yasuda, Kai Zhang, Indika Peabotuwage, Ximin Wang, Rui-Chang Quan, J. W. Ferry Slik, Richard T. Corlett, Eben Goodale and Rhett D. Harriso

    Priority areas for the conservation of perennial plants in China

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    With over 35,000 higher plants recorded, China is among the countries with the highest plant diversity. However, due to increasing human population, land-use intensification, and economic development, the habitat of most species is under considerable threat. Here we develop conservation priority maps covering all of China based on plant species distribution models in combination with spatially explicit decision making tools for systematic conservation planning. Our aim was to find spatial scenarios that maximize the success of conservation goals while minimizing the required land area to achieve these goals, so that economic development can proceed with minimal damage to existing biodiversity resources. We built species distribution models for 7427 vascular plant species at a 10 x 10' resolution covering whole China, using geo-referenced herbarium collections and detailed environmental data, corrected for spatial bias using a null model. Based on these models we mapped: (1) species richness centers for common species (3535), endemic species (1965) and Chinese red list species (1927); (2) priority areas for conservation, distinguishing between conservation targets for common species (15% of the predicted suitable habitat), endemic species (25% the predicted suitable habitat) and red list species (35% the predicted suitable habitat); and (3) downscaled land-use pattern in each priority area for conservation. Clear priorities for the development of a sustainable and feasible biodiversity conservation strategy can now be provided based on our maps at national and regional levels. (C) 2016 Elsevier Ltd. All rights reserved

    Using species distribution modeling to delineate the botanical richness patterns and phytogeographical regions of China

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    The millions of plant specimens that have been collected and stored in Chinese herbaria over the past similar to 110 years have recently been digitized and geo-referenced. Here we use this unique collection data set for species distribution modeling exercise aiming at mapping & explaining the botanical richness; delineating China's phytogeographical regions and investigating the environmental drivers of the dissimilarity patterns. We modeled distributions of 6,828 woody plants using MaxEnt and remove the collection bias using null model. The continental China was divided into different phytogeographical regions based on the dissimilarity patterns. An ordination and Getis-Ord Gi* hotspot spatial statistics were used to analysis the environmental drivers of the dissimilarity patterns. We found that the annual precipitation and temperature stability were responsible for observed species diversity. The mechanisms causing dissimilarity pattern seems differ among biogeographical regions. The identified environmental drivers of the dissimilarity patterns for southeast, southwest, northwest and northeast are annual precipitation, topographic & temperature stability, water deficit and temperature instability, respectively. For effective conservation of China's plant diversity, identifying the historical refuge and protection of high diversity areas in each of the identified floristic regions and their subdivisions will be essential

    On altitude dependent characters in Albinaria idaea (L. Pfeiffer, 1849), with a revision of the species (Gastropoda Pulmonata: Clausiliidae)

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    Several forms of Albinaria idaea (L. Pfeiffer, 1849) have been described as (sub)species from various sites on Mt. Ida (Central Crete). In recent years, however, much additional material has been collected, which made clear that no sharp boundaries exist between these forms. Moreover, several characters proved to be altitude dependent to a certain extent. It may be concluded that on Mt. Ida only a single evolutionary entity can be distinguished, viz. A. i. idaea. On the isolated Mt. Kedros, south-west of Mt. Ida, an undescribed allopatric form was found, which because of its smaller size and differences in altitude dependent characters was given subspecific rank as A. i. amabilis ssp. nov. On the Paximadia Isles, south of Central Crete, a percostate and a finely ribbed subspecies occur allopatrically. The finely ribbed one seems consubspecific with A. i. idaea; the percostate one was recently described as the separate subspecies A. i. pichcapunlla Schultes & Wiese, 1991
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