Guopeng REN - Academia.edu (original) (raw)

Papers by Guopeng REN

Biological Conservation, 2017

Science of the Total Environment, 2001

The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention... more The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention, especially in streams because of their sensitivity to climate change. In the past years, research mainly focused on understanding the role played by alpine streams' internal factors such as aquatic environmental variables, as well as physical and hydrological conditions, on the shaping of benthic macroinvertebrate communities. More recently, external factors such as terrestrial environments were included in analyses worldwide. In particular, the inherent properties constituting the ecological niche of specific species were considered as factors regulating dispersal and influencing community construction. The objective of this study was to reveal the distribution pattern and the driving factors regulating aquatic biodiversity in alpine streams. We hypothesized that the altitudinal distribution of aquatic macroinvertebrates could be explained by the interaction of the aquatic environment with both species' ecological niche and the terrestrial environment surrounding their habitat, and that rare species display a more pronounced pattern than widespread dominant species. To test these hypotheses, samples were collected from two alpine streams situated on opposite slopes of Biluo Snow Mountain in Yunnan Province, China. Results of statistical analyses showed poor explanatory power from aquatic environmental factors, while the differences in vegetation type and the ecological niche of the species played an important role in determining the distribution pattern of aquatic biodiversity. Furthermore, we found that the altitudinal distribution pattern of aquatic biodiversity exhibits a bimodal type, with rare species fitting the bimodal peaks. These findings call for a better inclusion and further investigation on the effects of the terrestrial environment on aquatic ecosystems.

American Journal of Primatology

Anthropogenic changes and fragmentation of natural habitats often exert a negative effect on reso... more Anthropogenic changes and fragmentation of natural habitats often exert a negative effect on resource availability and distribution, and the nutritional ecology and feeding behavior of nonhuman primates. The goals of this study are to examine food choice and to identify the nutritional profile of foods consumed by the Critically Endangered black snub-nosed monkey (Rhinopithecus strykeri). To accomplish our study goals, we presented cafeteria-style feeding trials of fresh food items collected in the home range of wild black snub-nosed monkeys to the only two captive R. strykeri, and compared the nutritional profiles of the leafy foods (buds, young, and mature leaves, 100 i23tems from 70 plant species) selected with those avoided (54 items from 48 plant species). Overall, the results indicate that captive R. strykeri selected foods that were higher in moisture (Mo; 77.7%), crude protein (CP; 21.2%), total nonstructural carbohydrates (TNC; 34.9%), and phosphorus (P; 0.37%) while tending to avoid foods with a neutral detergent fiber (NDF) content of greater than 46.8%. Leaves collected in autumn and selected by the monkeys were characterized by a slightly higher amount of metabolizable energy (ME) than those rejected (1,350 kJ/100 g vs. 1,268 kJ/100 g). In contrast, the protein content of foods collected and consumed during the spring was greater (22.9%) than in autumn (16.4%). Random Forests modeling, an ensemble learning method, indicated that the proportion of Mo, NDF, ME, CP, P, and TNC were among the most important factors in predicting which items were consumed by the captive R. strykeri during spring and autumn. On the basis of the nutritional profile of foods consumed across the two

Global Ecology and Conservation

Difficult to study species that inhabit inaccessible terrain, present significant challenges in o... more Difficult to study species that inhabit inaccessible terrain, present significant challenges in obtaining accurate ecological, distributional, and conservation information. To address these challenges, we used an effective set of time-and cost-efficient methods including interview-based surveys assisted by Google earth 3D maps to document the distributional range of 32 native animal taxa in the biodiverse but difficult to access Gaoligong Mountains (GLGMS), located on the northern Sino-Myanmar Border. Five threatened flagship species, including the black snub-nosed monkey (Rhinopithecus strykeri), the Skywalker hoolock gibbon (Hoolock tianxing), Shortridge's langur (Trachypithecus shortridgei), Sclater's monal (Lophophorus sclateri) and the Mishmi takin (Budorcas taxicolor) were selected for intensive surveys and used as surrogate taxa to study community biodiversity. Field surveys of each species were conducted to determine their presence/absence and to confirm the reliability of species distribution data obtained from interview-based surveys. Multi-criteria Decision Analyses were used along with data on habitat suitability (MAXENT) to prioritize transboundary conservation areas. Our results indicate that approximately 83.4% (10,398.7 km 2) of the remaining habitat with high biodiversity conservation value in the GLGMs is unprotected. This includes six large zones located along the northern Sino-Myanmar border, separated by rivers and human settlements. These areas should be designated as a transboundary World Nature Heritage Site, national parks, or wildlife sanctuaries. This study presents a reliable, rapid and integrative method for developing informed policies for conservation prioritization in data poor areas, which can be applied successfully to assess conservation priorities in other mountainous regions where obtaining data on biodiversity is difficult.

Global Ecology and Conservation

Remote Sensing

Remote mountainous regions are among the Earth’s last remaining wild spots, hosting rare ecosyste... more Remote mountainous regions are among the Earth’s last remaining wild spots, hosting rare ecosystems and rich biodiversity. Because of access difficulties and low population density, baseline information about natural and human-induced disturbances in these regions is often limited or nonexistent. Landsat time series offer invaluable opportunities to reconstruct past land cover changes. However, the applicability of this approach strongly depends on the availability of good quality, cloud-free images, acquired at a regular time interval, which in mountainous regions are often difficult to find. The present study analyzed burn scar detection capabilities of 11 widely used spectral indices (SI) at 1 to 5 years after fire events in four dominant vegetation groups in a mountainous region of northwest Yunnan, China. To evaluate their performances, we used M-statistic as a burned-unburned class separability index, and we adapted an existing metric to quantify the SI residual burn signal at...

Remote Sensing

An increasing number of end-users looking for ground data about fire activity in regions where ac... more An increasing number of end-users looking for ground data about fire activity in regions where accurate official datasets are not available adopt a free-of-charge global burned area (BA) and active fire (AF) products for applications at the local scale. One of the pressing requirements from the user community is an improved ability to detect small fires (less than 50 ha), whose impact on terrestrial environments is empirically known but poorly quantified, and is often excluded from global earth system models. The newest generation of BA algorithms combines the capabilities of both the BA and AF detection approaches, resulting in a general improvement of detection compared to their predecessors. Accuracy assessments of these products have been done in several ecosystems; but more complex ones, such as regions that are characterized by frequent small fires and steep terrain has never been assessed. This study contributes to the understanding of the performance of global BA and AF products with a first assessment of four selected datasets: MODIS-based MCD45A1; MCD64A1; MCD14ML; and, ESA's Fire_CCI in a mountainous region of northwest Yunnan; P.R. China. Due to the medium to coarse resolution of the tested products and the reduced sizes of fires (often smaller than 50 ha) we used a polygon intersection assessment method where the number and locations of fire events extracted from each dataset were compared against a reference dataset that was compiled using Landsat scenes. The results for the two sample years (2006 and 2009) show that the older, non-hybrid products MCD45A1 and, MCD14ML were the best performers with Sørensen index (F1 score) reaching 0.42 and 0.26 in 2006, and 0.24 and 0.24 in 2009, respectively, while producer's accuracies (PA) were 30% and 43% in 2006, and 16% and 47% in 2009, respectively. All of the four tested products obtained higher probabilities of detection when smaller fires were excluded from the assessment, with PAs for fires bigger than 50 ha being equal to 53% and 61% in 2006, 41% and 66% in 2009 for MCD45A1 and MCD14ML, respectively. Due to the technical limitations of the satellites' sensors, a relatively low performance of the four products was expected. Surprisingly, the new hybrid algorithms produced worse results than the former two. Fires smaller than 50 ha were poorly detected by the products except for the only AF product. These findings are significant for the future design of improved algorithms aiming for increased detection of small fires in a greater diversity of ecosystems.

Journal of Wildlife Management, Aug 10, 2013

The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 no... more The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 northwestern Yunnan counties (Lijiang, Shangri-la, Deqin, and Weixi) in the Trans-Himalayas to assess the conservation status of 9 gallinaceous forest birds. We developed maps depicting recent forest cover and modeled habitat availability of each gallinaceous forest bird based on 3 factors that restrict its distribution: geographic location, elevation range, and forest coverage. The conservation status of 4 species was inadequate, because ,10% of their respective potential habitats were within existing nature reserves. To predict the historic habitats of the species we studied, we also delineated a forest map from the late 1950s. We calculated the loss and fragmentation of potential habitats within the past 40 years as degree of habitat degradation. Our results showed that all 9 species became reduced and fragmented of their potential habitats from the late 1950s to 2002. Assessing habitat degradation and conservation status of wild species could help identify the threatened species with poor protection and degraded habitats, thereby warranting more attention in future conservation strategies. To protect those threatened species, it is urgent that the government should design new nature reserves to fill the conservation gaps, and enlarge and strengthen the management of existing natural reserves to reduce effects of human activities on their habitats.

Biological Conservation, 2016

International Journal of Geographical Information Science, 2015

ABSTRACT The vast accumulation of environmental data and the rapid development of geospatial visu... more ABSTRACT The vast accumulation of environmental data and the rapid development of geospatial visualization and analytical techniques make it possible for scientists to solicit information from local citizens to map spatial variation of geographic phenomena. However, data provided by citizens (referred to as citizen data in this article) suffers two limitations for mapping: bias in spatial coverage and imprecision in spatial location. This article presents an approach to minimizing the impacts of these two limitations of citizen data using geospatial analysis techniques. The approach reduces location imprecision by adopting a frequency-sampling strategy to identify representative presence locations from areas over which citizens observed the geographic phenomenon. The approach compensates for the spatial bias by weighting presence locations with cumulative visibility (the frequency at which a given location can be seen by local citizens). As a case study to demonstrate the principle, this approach was applied to map the habitat suitability of the black-and-white snub-nosed monkey (Rhinopithecus bieti) in Yunnan, China. Sightings of R. bieti were elicited from local citizens using a geovisualization platform and then processed with the proposed approach to predict a habitat-suitability map. Presence locations of R. bieti recorded by biologists through intensive field tracking were used to validate the predicted habitat-suitability map. Validation showed that the continuous Boyce index (Bcont(0.1)) calculated on the suitability map was 0.873 (95% CI: [0.810, 0.917]), indicating that the map was highly consistent with the field-observed distribution of R. bieti. Bcont(0.1) was much lower (0.173) for the suitability map predicted based on citizen data when location imprecision was not reduced and even lower (-0.048) when there was no compensation for spatial bias. This indicates that the proposed approach effectively minimized the impacts of location imprecision and spatial bias in citizen data and therefore effectively improved the quality of mapped spatial variation using citizen data. It further implies that, with the application of geospatial analysis techniques to properly account for limitations in citizen data, valuable information embedded in such data can be extracted and used for scientific mapping.

Remote Sensing of Environment, 2012

Forest cover change is one of the most important land cover change processes globally, and old-gr... more Forest cover change is one of the most important land cover change processes globally, and old-growth forests continue to disappear despite many efforts to protect them. At the same time, many countries are on a trajectory of increasing forest cover, and secondary, plantation, and scrub forests are a growing proportion of global forest cover. Remote sensing is a crucial tool for understanding how forests change in response to forest protection strategies and economic development, but most forest monitoring with satellite imagery does not distinguish old-growth forest from other forest types. Our goal was to measure changes in forest types, and especially old-growth forests, in the biodiversity hotspot of northwest Yunnan in southwest China. Northwest Yunnan is one of the poorest regions in China, and since the 1990s, the Chinese government has legislated strong forest protection and fostered the growth of ecotourism-based economic development. We used Landsat TM/ETM+ and MSS images, Support Vector Machines, and a multi-temporal composite classification technique to analyze change in forest types and the loss of old-growth forest in three distinct periods of forestry policy and ecotourism development from 1974 to 2009. Our analysis showed that logging rates decreased substantially from 1974 to 2009, and the proportion of forest cover increased from 62% in 1990 to 64% in 2009. However, clearing of high-diversity old-growth forest accelerated, from approximately 1100 hectares/year before the logging ban (1990 to 1999), to 1550 hectares/year after the logging ban (1999 to 2009). Paradoxically, old-growth forest clearing accelerated most rapidly where ecotourism was most prominent. Despite increasing overall forest cover, the proportion of old-growth forests declined from 26% in 1990, to 20% in 2009. The majority of forests cleared from 1974 to 1990 returned to either a nonforested land cover type (14%) or non-pine scrub forest (66%) in 2009, and our results suggest that most non-pine scrub forest was not on a successional trajectory towards high-diversity forest stands. That means that despite increasing forest cover, biodiversity likely continues to decline, a trend obscured by simple forest versus non-forest accounting. It also means that rapid development may pose inherent risks to biodiversity, since our study area arguably represents a "best-case scenario" for balancing development with maintenance of biodiversity, given strong forest protection policies and an emphasis on ecotourism development.

PLoS ONE, 2011

Environmental factors that affect spatiotemporal distribution patterns of animals usually include... more Environmental factors that affect spatiotemporal distribution patterns of animals usually include resource availability, temperature, and the risk of predation. However, they do not explain the counterintuitive preference of high elevation range in winter by the black-and-white snub-nosed monkey (Rhinopithecus bieti). We asked whether variation of sunshine along with elevations is the key driving force. To test this hypothesis, we conducted field surveys to demonstrate that there was a statistically significant pattern of high elevation use during winter. We then asked whether this pattern can be explained by certain environmental factors, namely temperature, sunshine duration and solar radiation. Finally, we concluded with a possible ecological mechanism for this pattern. In this study, we employed GIS technology to quantify solar radiation and sunshine duration across the monkey's range. Our results showed that: 1) R. bieti used the high altitude range between 4100-4400 m in winter although the yearly home range spanned from 3500-4500 m; 2) both solar radiation and sunshine duration increased with elevation while temperature decreased with elevation; 3) within the winter range, the use of range was significantly correlated with solar radiation and sunshine duration; 4) monkeys moved to the areas with high solar radiation and duration following a snowfall, where the snow melts faster and food is exposed earlier. We concluded that sunshine was the main factor that influences selection of high elevation habitat for R. bieti in winter. Since some other endotherms in the area exhibit similar winter distributional patterns, we developed a sunshine hypothesis to explain this phenomenon. In addition, our work also represented a new method of integrating GIS models into traditional field ecology research to study spatiotemporal distribution pattern of wildlife. We suggest that further theoretical and empirical studies are necessary for better understanding of sunshine influence on wildlife range use.

Journal of Wildlife Management, 2008

The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 no... more The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 northwestern Yunnan counties (Lijiang, Shangri-la, Deqin, and Weixi) in the Trans-Himalayas to assess the conservation status of 9 gallinaceous forest birds. We developed maps depicting recent forest cover and modeled habitat availability of each gallinaceous forest bird based on 3 factors that restrict its distribution: geographic location, elevation range, and forest coverage. The conservation status of 4 species was inadequate, because ,10% of their respective potential habitats were within existing nature reserves. To predict the historic habitats of the species we studied, we also delineated a forest map from the late 1950s. We calculated the loss and fragmentation of potential habitats within the past 40 years as degree of habitat degradation. Our results showed that all 9 species became reduced and fragmented of their potential habitats from the late 1950s to 2002. Assessing habitat degradation and conservation status of wild species could help identify the threatened species with poor protection and degraded habitats, thereby warranting more attention in future conservation strategies. To protect those threatened species, it is urgent that the government should design new nature reserves to fill the conservation gaps, and enlarge and strengthen the management of existing natural reserves to reduce effects of human activities on their habitats.

International Journal of Primatology, 2013

Your article is protected by copyright and all rights are held exclusively by Springer Science +B... more Your article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

International Journal of Primatology, 2011

Human impacts on the environment at local or regional scales largely depend on intrinsic characte... more Human impacts on the environment at local or regional scales largely depend on intrinsic characteristics of the population, such as household size, household number, and human population growth. These demographic factors can vary considerably among ethnic groups sharing similar ecological landscapes, yet the role of traditional cultural practices in shaping local environmental impacts is not well known for many parts of the world. We here quantify land-cover changes and their relation to the habitat of the endangered Rhinopithecus bieti in Tibet, in 2 areas populated by different ethnic groups (polyandrous Tibetans and monogamous Naxi) from 1986 to 2006. Results indicate that habitat of the monkey decreased greatly within our study area over the 20-yr period. Polyandrous and monogamous ethnic communities differed in household size, household number, population growth, and per capita and per household land use. The practice of polyandry by ethnic Tibetan appears to have reduced per capita resource consumption by reducing the growth of overall household number and increasing household size, which can mitigate the

Zoological Research, 2009

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) distribute in a restricted area of the T... more Black-and-white snub-nosed monkeys (Rhinopithecus bieti) distribute in a restricted area of the Trans-Himalayas between the Mekong and Yangtze River, at 26P o

Biological Conservation, 2010

... c, Kadoorie Farm & Botanic Garden, China Programme, Hong Kong, China.... more ... c, Kadoorie Farm & Botanic Garden, China Programme, Hong Kong, China. ... The Hainan gibbon has been regarded as an umbrella species for the local ecosystem (Chan et al., 2005a), which harbours rich biodiversity ( [Chan et al., 2005b] and [32] ); as such, changes in its ...

Biological Conservation, 2017

Science of the Total Environment, 2001

The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention... more The altitudinal distribution of biodiversity in alpine ecosystems has captured academic attention, especially in streams because of their sensitivity to climate change. In the past years, research mainly focused on understanding the role played by alpine streams' internal factors such as aquatic environmental variables, as well as physical and hydrological conditions, on the shaping of benthic macroinvertebrate communities. More recently, external factors such as terrestrial environments were included in analyses worldwide. In particular, the inherent properties constituting the ecological niche of specific species were considered as factors regulating dispersal and influencing community construction. The objective of this study was to reveal the distribution pattern and the driving factors regulating aquatic biodiversity in alpine streams. We hypothesized that the altitudinal distribution of aquatic macroinvertebrates could be explained by the interaction of the aquatic environment with both species' ecological niche and the terrestrial environment surrounding their habitat, and that rare species display a more pronounced pattern than widespread dominant species. To test these hypotheses, samples were collected from two alpine streams situated on opposite slopes of Biluo Snow Mountain in Yunnan Province, China. Results of statistical analyses showed poor explanatory power from aquatic environmental factors, while the differences in vegetation type and the ecological niche of the species played an important role in determining the distribution pattern of aquatic biodiversity. Furthermore, we found that the altitudinal distribution pattern of aquatic biodiversity exhibits a bimodal type, with rare species fitting the bimodal peaks. These findings call for a better inclusion and further investigation on the effects of the terrestrial environment on aquatic ecosystems.

American Journal of Primatology

Anthropogenic changes and fragmentation of natural habitats often exert a negative effect on reso... more Anthropogenic changes and fragmentation of natural habitats often exert a negative effect on resource availability and distribution, and the nutritional ecology and feeding behavior of nonhuman primates. The goals of this study are to examine food choice and to identify the nutritional profile of foods consumed by the Critically Endangered black snub-nosed monkey (Rhinopithecus strykeri). To accomplish our study goals, we presented cafeteria-style feeding trials of fresh food items collected in the home range of wild black snub-nosed monkeys to the only two captive R. strykeri, and compared the nutritional profiles of the leafy foods (buds, young, and mature leaves, 100 i23tems from 70 plant species) selected with those avoided (54 items from 48 plant species). Overall, the results indicate that captive R. strykeri selected foods that were higher in moisture (Mo; 77.7%), crude protein (CP; 21.2%), total nonstructural carbohydrates (TNC; 34.9%), and phosphorus (P; 0.37%) while tending to avoid foods with a neutral detergent fiber (NDF) content of greater than 46.8%. Leaves collected in autumn and selected by the monkeys were characterized by a slightly higher amount of metabolizable energy (ME) than those rejected (1,350 kJ/100 g vs. 1,268 kJ/100 g). In contrast, the protein content of foods collected and consumed during the spring was greater (22.9%) than in autumn (16.4%). Random Forests modeling, an ensemble learning method, indicated that the proportion of Mo, NDF, ME, CP, P, and TNC were among the most important factors in predicting which items were consumed by the captive R. strykeri during spring and autumn. On the basis of the nutritional profile of foods consumed across the two

Global Ecology and Conservation

Difficult to study species that inhabit inaccessible terrain, present significant challenges in o... more Difficult to study species that inhabit inaccessible terrain, present significant challenges in obtaining accurate ecological, distributional, and conservation information. To address these challenges, we used an effective set of time-and cost-efficient methods including interview-based surveys assisted by Google earth 3D maps to document the distributional range of 32 native animal taxa in the biodiverse but difficult to access Gaoligong Mountains (GLGMS), located on the northern Sino-Myanmar Border. Five threatened flagship species, including the black snub-nosed monkey (Rhinopithecus strykeri), the Skywalker hoolock gibbon (Hoolock tianxing), Shortridge's langur (Trachypithecus shortridgei), Sclater's monal (Lophophorus sclateri) and the Mishmi takin (Budorcas taxicolor) were selected for intensive surveys and used as surrogate taxa to study community biodiversity. Field surveys of each species were conducted to determine their presence/absence and to confirm the reliability of species distribution data obtained from interview-based surveys. Multi-criteria Decision Analyses were used along with data on habitat suitability (MAXENT) to prioritize transboundary conservation areas. Our results indicate that approximately 83.4% (10,398.7 km 2) of the remaining habitat with high biodiversity conservation value in the GLGMs is unprotected. This includes six large zones located along the northern Sino-Myanmar border, separated by rivers and human settlements. These areas should be designated as a transboundary World Nature Heritage Site, national parks, or wildlife sanctuaries. This study presents a reliable, rapid and integrative method for developing informed policies for conservation prioritization in data poor areas, which can be applied successfully to assess conservation priorities in other mountainous regions where obtaining data on biodiversity is difficult.

Global Ecology and Conservation

Remote Sensing

Remote mountainous regions are among the Earth’s last remaining wild spots, hosting rare ecosyste... more Remote mountainous regions are among the Earth’s last remaining wild spots, hosting rare ecosystems and rich biodiversity. Because of access difficulties and low population density, baseline information about natural and human-induced disturbances in these regions is often limited or nonexistent. Landsat time series offer invaluable opportunities to reconstruct past land cover changes. However, the applicability of this approach strongly depends on the availability of good quality, cloud-free images, acquired at a regular time interval, which in mountainous regions are often difficult to find. The present study analyzed burn scar detection capabilities of 11 widely used spectral indices (SI) at 1 to 5 years after fire events in four dominant vegetation groups in a mountainous region of northwest Yunnan, China. To evaluate their performances, we used M-statistic as a burned-unburned class separability index, and we adapted an existing metric to quantify the SI residual burn signal at...

Remote Sensing

An increasing number of end-users looking for ground data about fire activity in regions where ac... more An increasing number of end-users looking for ground data about fire activity in regions where accurate official datasets are not available adopt a free-of-charge global burned area (BA) and active fire (AF) products for applications at the local scale. One of the pressing requirements from the user community is an improved ability to detect small fires (less than 50 ha), whose impact on terrestrial environments is empirically known but poorly quantified, and is often excluded from global earth system models. The newest generation of BA algorithms combines the capabilities of both the BA and AF detection approaches, resulting in a general improvement of detection compared to their predecessors. Accuracy assessments of these products have been done in several ecosystems; but more complex ones, such as regions that are characterized by frequent small fires and steep terrain has never been assessed. This study contributes to the understanding of the performance of global BA and AF products with a first assessment of four selected datasets: MODIS-based MCD45A1; MCD64A1; MCD14ML; and, ESA's Fire_CCI in a mountainous region of northwest Yunnan; P.R. China. Due to the medium to coarse resolution of the tested products and the reduced sizes of fires (often smaller than 50 ha) we used a polygon intersection assessment method where the number and locations of fire events extracted from each dataset were compared against a reference dataset that was compiled using Landsat scenes. The results for the two sample years (2006 and 2009) show that the older, non-hybrid products MCD45A1 and, MCD14ML were the best performers with Sørensen index (F1 score) reaching 0.42 and 0.26 in 2006, and 0.24 and 0.24 in 2009, respectively, while producer's accuracies (PA) were 30% and 43% in 2006, and 16% and 47% in 2009, respectively. All of the four tested products obtained higher probabilities of detection when smaller fires were excluded from the assessment, with PAs for fires bigger than 50 ha being equal to 53% and 61% in 2006, 41% and 66% in 2009 for MCD45A1 and MCD14ML, respectively. Due to the technical limitations of the satellites' sensors, a relatively low performance of the four products was expected. Surprisingly, the new hybrid algorithms produced worse results than the former two. Fires smaller than 50 ha were poorly detected by the products except for the only AF product. These findings are significant for the future design of improved algorithms aiming for increased detection of small fires in a greater diversity of ecosystems.

Journal of Wildlife Management, Aug 10, 2013

The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 no... more The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 northwestern Yunnan counties (Lijiang, Shangri-la, Deqin, and Weixi) in the Trans-Himalayas to assess the conservation status of 9 gallinaceous forest birds. We developed maps depicting recent forest cover and modeled habitat availability of each gallinaceous forest bird based on 3 factors that restrict its distribution: geographic location, elevation range, and forest coverage. The conservation status of 4 species was inadequate, because ,10% of their respective potential habitats were within existing nature reserves. To predict the historic habitats of the species we studied, we also delineated a forest map from the late 1950s. We calculated the loss and fragmentation of potential habitats within the past 40 years as degree of habitat degradation. Our results showed that all 9 species became reduced and fragmented of their potential habitats from the late 1950s to 2002. Assessing habitat degradation and conservation status of wild species could help identify the threatened species with poor protection and degraded habitats, thereby warranting more attention in future conservation strategies. To protect those threatened species, it is urgent that the government should design new nature reserves to fill the conservation gaps, and enlarge and strengthen the management of existing natural reserves to reduce effects of human activities on their habitats.

Biological Conservation, 2016

International Journal of Geographical Information Science, 2015

ABSTRACT The vast accumulation of environmental data and the rapid development of geospatial visu... more ABSTRACT The vast accumulation of environmental data and the rapid development of geospatial visualization and analytical techniques make it possible for scientists to solicit information from local citizens to map spatial variation of geographic phenomena. However, data provided by citizens (referred to as citizen data in this article) suffers two limitations for mapping: bias in spatial coverage and imprecision in spatial location. This article presents an approach to minimizing the impacts of these two limitations of citizen data using geospatial analysis techniques. The approach reduces location imprecision by adopting a frequency-sampling strategy to identify representative presence locations from areas over which citizens observed the geographic phenomenon. The approach compensates for the spatial bias by weighting presence locations with cumulative visibility (the frequency at which a given location can be seen by local citizens). As a case study to demonstrate the principle, this approach was applied to map the habitat suitability of the black-and-white snub-nosed monkey (Rhinopithecus bieti) in Yunnan, China. Sightings of R. bieti were elicited from local citizens using a geovisualization platform and then processed with the proposed approach to predict a habitat-suitability map. Presence locations of R. bieti recorded by biologists through intensive field tracking were used to validate the predicted habitat-suitability map. Validation showed that the continuous Boyce index (Bcont(0.1)) calculated on the suitability map was 0.873 (95% CI: [0.810, 0.917]), indicating that the map was highly consistent with the field-observed distribution of R. bieti. Bcont(0.1) was much lower (0.173) for the suitability map predicted based on citizen data when location imprecision was not reduced and even lower (-0.048) when there was no compensation for spatial bias. This indicates that the proposed approach effectively minimized the impacts of location imprecision and spatial bias in citizen data and therefore effectively improved the quality of mapped spatial variation using citizen data. It further implies that, with the application of geospatial analysis techniques to properly account for limitations in citizen data, valuable information embedded in such data can be extracted and used for scientific mapping.

Remote Sensing of Environment, 2012

Forest cover change is one of the most important land cover change processes globally, and old-gr... more Forest cover change is one of the most important land cover change processes globally, and old-growth forests continue to disappear despite many efforts to protect them. At the same time, many countries are on a trajectory of increasing forest cover, and secondary, plantation, and scrub forests are a growing proportion of global forest cover. Remote sensing is a crucial tool for understanding how forests change in response to forest protection strategies and economic development, but most forest monitoring with satellite imagery does not distinguish old-growth forest from other forest types. Our goal was to measure changes in forest types, and especially old-growth forests, in the biodiversity hotspot of northwest Yunnan in southwest China. Northwest Yunnan is one of the poorest regions in China, and since the 1990s, the Chinese government has legislated strong forest protection and fostered the growth of ecotourism-based economic development. We used Landsat TM/ETM+ and MSS images, Support Vector Machines, and a multi-temporal composite classification technique to analyze change in forest types and the loss of old-growth forest in three distinct periods of forestry policy and ecotourism development from 1974 to 2009. Our analysis showed that logging rates decreased substantially from 1974 to 2009, and the proportion of forest cover increased from 62% in 1990 to 64% in 2009. However, clearing of high-diversity old-growth forest accelerated, from approximately 1100 hectares/year before the logging ban (1990 to 1999), to 1550 hectares/year after the logging ban (1999 to 2009). Paradoxically, old-growth forest clearing accelerated most rapidly where ecotourism was most prominent. Despite increasing overall forest cover, the proportion of old-growth forests declined from 26% in 1990, to 20% in 2009. The majority of forests cleared from 1974 to 1990 returned to either a nonforested land cover type (14%) or non-pine scrub forest (66%) in 2009, and our results suggest that most non-pine scrub forest was not on a successional trajectory towards high-diversity forest stands. That means that despite increasing forest cover, biodiversity likely continues to decline, a trend obscured by simple forest versus non-forest accounting. It also means that rapid development may pose inherent risks to biodiversity, since our study area arguably represents a "best-case scenario" for balancing development with maintenance of biodiversity, given strong forest protection policies and an emphasis on ecotourism development.

PLoS ONE, 2011

Environmental factors that affect spatiotemporal distribution patterns of animals usually include... more Environmental factors that affect spatiotemporal distribution patterns of animals usually include resource availability, temperature, and the risk of predation. However, they do not explain the counterintuitive preference of high elevation range in winter by the black-and-white snub-nosed monkey (Rhinopithecus bieti). We asked whether variation of sunshine along with elevations is the key driving force. To test this hypothesis, we conducted field surveys to demonstrate that there was a statistically significant pattern of high elevation use during winter. We then asked whether this pattern can be explained by certain environmental factors, namely temperature, sunshine duration and solar radiation. Finally, we concluded with a possible ecological mechanism for this pattern. In this study, we employed GIS technology to quantify solar radiation and sunshine duration across the monkey's range. Our results showed that: 1) R. bieti used the high altitude range between 4100-4400 m in winter although the yearly home range spanned from 3500-4500 m; 2) both solar radiation and sunshine duration increased with elevation while temperature decreased with elevation; 3) within the winter range, the use of range was significantly correlated with solar radiation and sunshine duration; 4) monkeys moved to the areas with high solar radiation and duration following a snowfall, where the snow melts faster and food is exposed earlier. We concluded that sunshine was the main factor that influences selection of high elevation habitat for R. bieti in winter. Since some other endotherms in the area exhibit similar winter distributional patterns, we developed a sunshine hypothesis to explain this phenomenon. In addition, our work also represented a new method of integrating GIS models into traditional field ecology research to study spatiotemporal distribution pattern of wildlife. We suggest that further theoretical and empirical studies are necessary for better understanding of sunshine influence on wildlife range use.

Journal of Wildlife Management, 2008

The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 no... more The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 northwestern Yunnan counties (Lijiang, Shangri-la, Deqin, and Weixi) in the Trans-Himalayas to assess the conservation status of 9 gallinaceous forest birds. We developed maps depicting recent forest cover and modeled habitat availability of each gallinaceous forest bird based on 3 factors that restrict its distribution: geographic location, elevation range, and forest coverage. The conservation status of 4 species was inadequate, because ,10% of their respective potential habitats were within existing nature reserves. To predict the historic habitats of the species we studied, we also delineated a forest map from the late 1950s. We calculated the loss and fragmentation of potential habitats within the past 40 years as degree of habitat degradation. Our results showed that all 9 species became reduced and fragmented of their potential habitats from the late 1950s to 2002. Assessing habitat degradation and conservation status of wild species could help identify the threatened species with poor protection and degraded habitats, thereby warranting more attention in future conservation strategies. To protect those threatened species, it is urgent that the government should design new nature reserves to fill the conservation gaps, and enlarge and strengthen the management of existing natural reserves to reduce effects of human activities on their habitats.

International Journal of Primatology, 2013

Your article is protected by copyright and all rights are held exclusively by Springer Science +B... more Your article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

International Journal of Primatology, 2011

Human impacts on the environment at local or regional scales largely depend on intrinsic characte... more Human impacts on the environment at local or regional scales largely depend on intrinsic characteristics of the population, such as household size, household number, and human population growth. These demographic factors can vary considerably among ethnic groups sharing similar ecological landscapes, yet the role of traditional cultural practices in shaping local environmental impacts is not well known for many parts of the world. We here quantify land-cover changes and their relation to the habitat of the endangered Rhinopithecus bieti in Tibet, in 2 areas populated by different ethnic groups (polyandrous Tibetans and monogamous Naxi) from 1986 to 2006. Results indicate that habitat of the monkey decreased greatly within our study area over the 20-yr period. Polyandrous and monogamous ethnic communities differed in household size, household number, population growth, and per capita and per household land use. The practice of polyandry by ethnic Tibetan appears to have reduced per capita resource consumption by reducing the growth of overall household number and increasing household size, which can mitigate the

Zoological Research, 2009

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) distribute in a restricted area of the T... more Black-and-white snub-nosed monkeys (Rhinopithecus bieti) distribute in a restricted area of the Trans-Himalayas between the Mekong and Yangtze River, at 26P o

Biological Conservation, 2010

... c, Kadoorie Farm & Botanic Garden, China Programme, Hong Kong, China.... more ... c, Kadoorie Farm & Botanic Garden, China Programme, Hong Kong, China. ... The Hainan gibbon has been regarded as an umbrella species for the local ecosystem (Chan et al., 2005a), which harbours rich biodiversity ( [Chan et al., 2005b] and [32] ); as such, changes in its ...