[show abstract][hide abstract] ABSTRACT: Natural disasters affect forest ecosystems in profound and complex ways. Artificial restoration projects have been conducted worldwide to repair disaster damage to forests, but the efficacy of such projects in light of naturally occurring recovery processes is rarely evaluated. To fill such an important knowledge gap, we investigated forest recovery and restoration in the world-renowned Wolong Nature Reserve in Sichuan, China after the catastrophic Wenchuan earthquake (magnitude 8.0) in 2008, which caused considerable damage to the forest and habitat of the endangered giant panda. This was the first multi-year field study to document natural recovery of forests in response to this disaster. Forest sampling conducted in panda habitat over a four-year period after the earthquake revealed that natural recovery was rapid, with vegetation covering roughly 70% of once denuded sites by the fourth sampling year. Vegetation recovery was further improved in sampled artificial restoration sites, which recovered from an average of 30% vegetation cover to 70% in only one year. Factors including soil cover and slope were correlated with successful vegetation recovery. New information learned from the multi-year field data provided a finer scale context for understanding the effects of disasters, a novel contribution considering that the majority of previous work has been conducted at the broader scale using remote sensing. Spatial analysis revealed that restoration sites were mainly distributed in areas of suitable slopes and elevations, but a measurable proportion (30–40%) were located too far from the existing panda distribution area and too close to human settlements. The restoration project has thus far had limited direct effect on giant panda conservation, but has indirect effects on improving forest cover in areas previously affected by human disturbances. This study provides a useful reference for understanding conditions affecting forest recovery, which can inform decision-making surrounding the implementation of forest restoration projects and conservation of endangered species, not only in China but also around the world.
Forest Ecology and Management 05/2014; 319:1-9. · 2.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Livestock production is one of the greatest threats to biodiversity worldwide. However, impacts of livestock on endangered species have been understudied, particularly across the livestock-wildlife interface in forested protected areas. We investigated the impact of an emerging livestock sector in China's renowned Wolong Nature Reserve for giant pandas. We integrated empirical data from field surveys, remotely sensed imagery, and GPS collar tracking to analyze (1) the spatial distribution of horses in giant panda habitat, (2) space use and habitat selection patterns of horses and pandas, and (3) the impact of horses on pandas and bamboo (panda's main food source). We discovered that the horse distribution overlapped with suitable giant panda habitat. Horses had smaller home ranges than pandas but both species showed similarities in habitat selection. Horses consumed considerable amounts of bamboo, and may have resulted in a decline in panda habitat use. Our study highlights the need to formulate policies to address this emerging threat to the endangered giant panda. It also has implications for understanding livestock impacts in other protected areas across the globe.
Journal for Nature Conservation 01/2014; · 1.54 Impact Factor
[show abstract][hide abstract] ABSTRACT: There is an urgent requirement to examine the quality of harvested rainwater for potable and non-potable purposes, based on the type of roofing material. In this study, we examined the effect on the quality of harvested rainwater of conventional roofing materials (concrete, asphalt and ceramic tile roofs) compared with alternative roofing materials (green roof). The results showed that the ceramic tile roof was the most suitable for rainwater-harvesting applications because of the lower concentrations of leachable pollutants. However, in this study, the green roof was not suitable for rainwater harvesting applications. In addition, seasonal trends in water quality parameters showed that pollutants in roof runoff in summer and autumn were lower than those in winter and spring. This study revealed that the quality of harvested rainwater was significantly affected by the roofing material; therefore, local government and urban planners should develop stricter testing programs and produce more weathering resistant roofing materials to allow the harvesting of rainwater for domestic and public uses.
Journal of Environmental Management 12/2013; 132C:178-187. · 3.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: Abstract Systematic evaluation of the environmental and socioeconomic effects of Payments for Ecosystem Services (PES) programs is crucial for guiding policy design and implementation. We evaluated the performance of the Natural Forest Conservation Program (NFCP), a national PES program of China, in the Wolong Nature Reserve for giant pandas. The environmental effects of the NFCP were evaluated through a historical trend (1965–2001) analysis of forest cover to estimate a counter-factual (i.e., without-PES) forest cover baseline for 2007. The socioeconomic effects of the NFCP were evaluated using data collected through household interviews carried out before and after NFCP implementation in 2001. Our results suggest that the NFCP was not only significantly associated with increases in forest cover, but also had both positive (e.g., labor reduction for fuelwood collection) and negative (e.g., economic losses due to crop raiding by wildlife) effects on local households. Results from this study emphasize the importance of integrating local conditions and understanding underlying mechanisms to enhance the performance of PES programs. Our findings are useful for the design and implementation of successful conservation policies not only in our study area but also in similar places around the world.
Journal of Environmental Management 09/2013; 127:86-95. · 3.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: After long periods of deforestation, forest transition has occurred globally, but the causes of forest transition in different countries are highly variable. Conservation policies may play important roles in facilitating forest transition around the world, including China. To restore forests and protect the remaining natural forests, the Chinese government initiated two nationwide conservation policies in the late 1990s – the Natural Forest Conservation Program (NFCP) and the Grain-To-Green Program (GTGP). While some studies have discussed the environmental and socioeconomic effects of each of these policies independently and others have attributed forest recovery to both policies without rigorous and quantitative analysis, it is necessary to quantify the outcomes of these two conservation policies simultaneously because the two policies have been implemented at the same time. To fill this knowledge gap, this study quantitatively evaluated the effects of the two conservation policies on forest cover change between 2001 and 2008 in 108 townships located in two important giant panda habitat regions – the Qinling Mountains region in Shaanxi Province and the Sichuan Giant Panda Sanctuary in Sichuan Province. Annual forest cover change rate was evaluated using a land-cover product (MCD12Q1) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). This product proved to be highly accurate in the study region (overall accuracy was ca. 87%, using 425 ground truth points collected in the field), thus suitable for the forest change analysis performed. Results showed that within the timeframe evaluated, 94% of townships (i.e., 101 out of 108) in both regions exhibited either increases or no changes in forest cover. After accounting for a variety of socioeconomic and biophysical attributes, a linear regression model suggests that the GTGP had a positive and significant effect on the annual forest cover change rate after seven years of implementation. Our results also suggest that elevation has a significant positive effect on forest cover change, while the percentage of agricultural population, initial forest cover in 2001, and the interaction term of elevation and slope had negative significant effects. Findings from this study will be useful for evaluating the implementation of current conservation policies, designing future conservation policies, developing future giant panda habitat conservation projects, and achieving forest sustainability in China and elsewhere.
[show abstract][hide abstract] ABSTRACT: This study investigates the quality of stormwater runoff from a driveway in the southwest mountainous urban area of Chongqing, China, from 2010 to 2011. The results showed that the mean concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 4.1, 2.4, and 2.2 times the grade V levels of the national surface water standard of China. The pollutant concentration peak preceded or synchronized with the rainfall intensity peak and occurred 10 min after the runoff started. The significant high pollutant concentration in the initial stage of the rainfall suggested that first flush control is necessary, especially for the most polluted constitutes, such as total suspended solids, COD, and TN. Three potential pollution sources were identified: the atmospheric dry and wet deposition (TN, NO3 (-)-N, NH4 (+)-N, and DCu), the road sediment and materials (total suspended solids, COD, and TP), and the vehicle emissions (DPb and DZn). Therefore, this study indicates that reductions in road sediments and material pollution and dry and wet deposition should be the priority factors for pollution control of road stormwater runoff in mountainous urban areas.
Environmental Monitoring and Assessment 06/2013; · 1.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Interactions between distant places are increasingly widespread and influential, often leading to unexpected outcomes with profound implications for sustainability. Numerous sustainability studies have been conducted within a particular place with little attention to the impacts of distant interactions on sustainability in multiple places. Although distant forces have been studied, they are usually treated as exogenous variables and feedbacks have rarely been considered. To understand and integrate various distant interactions better, we propose an integrated framework based on telecoupling, an umbrella concept that refers to socioeconomic and environmental interactions over distances. The concept of telecoupling is a logical extension of research on coupled human and natural systems, in which interactions occur within particular geographic locations. The telecoupling framework contains five major interrelated components, i.e., coupled human and natural systems, flows, agents, causes, and effects. We illustrate the framework using two examples of distant interactions associated with trade of agricultural commodities and invasive species, highlight the implications of the framework, and discuss research needs and approaches to move research on telecouplings forward. The framework can help to analyze system components and their interrelationships, identify research gaps, detect hidden costs and untapped benefits, provide a useful means to incorporate feedbacks as well as trade-offs and synergies across multiple systems (sending, receiving, and spillover systems), and improve the understanding of distant interactions and the effectiveness of policies for socioeconomic and environmental sustainability from local to global levels.
ECOLOGY AND SOCIETY 06/2013; 18(2). · 3.31 Impact Factor
[show abstract][hide abstract] ABSTRACT: We quantitatively describe the impacts of urbanization on the accumulation of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) in urban soils as well as their health risks to residents. Residential building age, population density, road density, and distance from urban center were used as urbanization level indicators. Significant correlations were found between those urbanization indicators and the amounts of PAHs, Cu, Cd, Pb, Zn and As in residential soils. The exposure time of soils to urban air was the primary factor affecting soil pollution, followed by local road density and population density. Factor analysis suggested that 59.0% of the elevated pollutant concentrations were caused by citywide uniform deposition, and 15.3% were resulted from short-range deposition and/or non-combustion processes. The combined health risks posed by soil PAHs and HMs were aggravated with time and can be expressed as functions of residence age, road density, and other urbanization indicators.
[show abstract][hide abstract] ABSTRACT: Conservation policies are emerging in many places around the world, many of which involve payment for ecosystem services (PES) schemes. PES schemes provide economic incentives for forgoing land uses that reduce the provision of ecosystem services. The efficiency of such schemes depends not only on the ecosystem services provided by an area but also on the willingness of local people to forgo their land use activities. Targeting land for enrollment in PES schemes on the basis of the potential provision of ecosystem services and on the willingness to forgo certain economic activities, may therefore improve the efficiency of these schemes. The objective of this study was to develop a targeting approach, based on three surrogates derived from remotely sensed and ancillary data, for identifying land to be enrolled in one of the largest PES schemes in the world: China's Grain-to-Green Program (GTGP). The GTGP encourages farmers to return steep hillside cropland to forest by providing cash, grain and tree seedlings. The three surrogates used in the targeting approach were slope index, cropland probability, and GTGP enrollment probability. Combining these surrogates through Bernoulli trials allows targeting areas under cropland, with low opportunity costs for farmers and with potentially high soil erosion and landslide susceptibility. Results of applying the targeting approach in a case study area (Baoxing County, Sichuan Province, China) show that around half of the land currently enrolled is placed in areas with gentle slopes and tend to be located distant from forest areas. This reduces the potential benefits obtained from the GTGP. Targeting land using the proposed approach may double the benefits obtained from the program under the same budget, thus improving its efficiency. The approach may be applied to the entire GTGP implementation area in China and with proper modifications it may also be applicable to similar PES programs around the world.
[show abstract][hide abstract] ABSTRACT: Climate change is threatening global ecosystems through its impact on the survival of individual species and their ecological functions. Despite the important role of understorey plants in forest ecosystems, climate impact assessments on understorey plants and their role in supporting wildlife habitat are scarce in the literature. Here we assess climate-change impacts on understorey bamboo species with an emphasis on their ecological function as a food resource for endangered giant pandas (Ailuropoda melanoleuca). An ensemble of bamboo distribution projections associated with multiple climate-change projections and bamboo dispersal scenarios indicates a substantial reduction in the distributional ranges of three dominant bamboo species in the Qinling Mountains, China during the twenty-first century. As these three species comprise almost the entire diet of the panda population in the region, the projected changes in bamboo distribution suggest a potential shortage of food for this population, unless alternative food sources become available. Although the projections were developed under unavoidable simplifying assumptions and uncertainties, they indicate potential challenges for panda conservation and underscore the importance of incorporating interspecific interactions into climate-change impact assessments and associated conservation planning.
[show abstract][hide abstract] ABSTRACT: Diffusive carbon dioxide (CO2) emissions from the water surface of the Three Gorges Reservoir, currently the largest hydroelectric reservoir in the world, were measured using floating static chambers over the course of a yearlong survey. The results showed that the average annual CO2 flux was (163.3 ± 117.4) mg CO2/(m2hr) at the reservoir surface, which was larger than the CO2 flux in most boreal and temperate reservoirs but lower than that in tropical reservoirs. Significant spatial variations in CO2 flux were observed at four measured sites, with the largest flux measured at Wushan (221.9 mg CO2/(m2hr)) and the smallest flux measured at Zigui (88.6 mg CO2/(m2hr)); these differences were probably related to the average water velocities at different sites. Seasonal variations in CO2 flux were also observed at four sites, starting to increase in January, continuously rising until peaking in the summer (June–August) and gradually decreasing thereafter. Seasonal variations in CO2 flux could reflect seasonal dynamics in pH, water velocity, and temperature. Since the spatial and temporal variations in CO2 flux were significant and dependent on multiple physical, chemical, and hydrological factors, it is suggested that long-term measurements should be made on a large spatial scale to assess the climatic influence of hydropower in China, as well as the rest of the world.
Journal of Environmental Sciences 01/2013; 25(11):2229–2238. · 1.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid (PLFA) abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed “∪” shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram+ to Gram-bacteria, formed “∩” shaped quadratic functions, and the ratio of cy17:0 to 16:1?7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiohydrolase activity formed “∪” shaped quadratic functions. Soil N:P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N:P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.
Journal of Environmental Sciences 01/2013; 25(10):2102–2111. · 1.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Assessing species composition and its changes through time across broad geographic regions is time consuming and a difﬁcult endeavor. The synoptic view provided by imaging remote sensors offers an alternative. But while many studies have developed procedures for assessing biodiversity using multi- and hyper-spectral imagery, they may only provide snapshots at particular months/seasons due to the seasonal variability of spectral characteristics induced by vegetated land surface phenologies. Thus, procedures for remotely assessing biodiversity patterns may not fully represent the biodiversity on the ground if vegetated land surface phenologies are not considered. Using Mantel tests, ordinarily least square regression models and spatial autoregressive models, we assessed the relationship between ﬂoristic diversity and vegetated land surface phenologies, as captured by time series of vegetation indices derived from data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS). The relationship was calibrated with data from temperate montane forests of the Qinling Mountains region, Shaanxi Province, China. Our results show that ﬂoristically similar areas also exhibit a comparable similarity in phenological characteristics. However, phenological similarity obtained using the Visible Atmospherically Resistant Index (VARI), a spectral vegetation index found to be not only sensitive to changes in chlorophyll content but also linearly related with the relative content of foliar anthocyanins, exhibited the strongest relationship with ﬂoristic similarity. Therefore, analysis of the temporal dynamics of pigments through the use of satellite-derived metrics, such as VARI, may be used for evaluating the spatial patterns and temporal dynamics of species composition across broad geographic regions.
Remote Sensing of Environment 06/2012; · 5.10 Impact Factor
[show abstract][hide abstract] ABSTRACT: Methane (CH4) emissions from the drawdown area of the Three
Gorges Reservoir (TGR) have not been thoroughly investigated even though
the drawdown area encompasses one third of the reservoir surface. In
this study, CH4 emissions from different land uses were
measured in the TGR drawdown area. The average diffusive CH4
emissions were 2.61, 0.19, 0.18, and 0.12 mg CH4
m-2 h-1 in rice paddies, fallow lands, deforested
lands, and croplands, respectively, and were positively related to the
duration of the inundated season among the latter three land uses. On
average the drawdown areas studied here (except rice paddies) were
sources in the inundated season (0.22 ± 0.26 mg CH4
m-2 h-1) and a sink in the drained season (-0.008
± 0.035 mg CH4 m-2 h-1). The
water level was the dominant factor that controlled whether the drawdown
area was either inundated or drained, which in turn determined whether
the drawdown area was a source or sink of CH4 emissions. The
average diffusive CH4 emissions from the fallow lands,
croplands, and deforested lands increased as the distance from the dam
increased from Zigui (0.10 ± 0.15 mg CH4
m-2 h-1) to Wushan (0.15 ± 0.29 mg
CH4 m-2 h-1) to Yunyang (0.24 ±
0.27 mg CH4 m-2 h-1), which could
reflect different sediment characteristics and water velocities. The
total CH4 emission from the drawdown area was estimated to
range from 1033.5 to 1333.9 Mg CH4 yr-1, which
would account for 42-54% of the total CH4 emissions from the
water surface of TGR.
Journal of Geophysical Research 05/2012; 117(D10):10109-. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: The O(3) uptake in 17 adult trees of six urban species was evaluated by the sap flow-based approach under free atmospheric conditions. The results showed very large species differences in ground area scaled whole-tree ozone uptake (F(o)₃), with estimates ranging from 0.61 ± 0.07 nmol m(-2) s(-1) in Robinia pseudoacacia to 4.80 ± 1.04 nmol m(-2) s(-1) in Magnolia liliiflora. However, average F(o)₃by deciduous foliages was not significantly higher than that by evergreen ones (3.13 vs 2.21 nmol m(-2) s(-1), p = 0.160). Species of high canopy conductance for O(3) (G(o)₃) took up more O(3) than those of low G(o)₃, but that their sensitivity to vapour pressure deficit (D) were also higher, and their F(o)₃decreased faster with increasing D, regardless of species. The responses of F(o)₃to D and total radiation led to the relative high flux of O(3) uptake, indicating high ozone risk for urban tree species.
[show abstract][hide abstract] ABSTRACT: Ecological risks of heavy metals in urban soils were evaluated using Beijing, China as an example. Cadmium, Cu, Zn, Pb, Cr and Ni contents of 233 surface soils sampled by 1 min latitude × 1 min longitude grid were used to identify their spatial distribution patterns and potential emission sources. Throughout the city, longer the duration of urbanization greater was the accumulations of heavy metals especially, Cd, Cu, Pb, and Zn. The soil Zn mainly came from the wears of vehicular tires. Point source emissions of heavy metals were few and far in the downwind south-east quadrant of Beijing. The calculated risk indices showed potential median eco-risks in the ancient central city. No potential high eco-risk due to soil-borne heavy metals was found. The potential medium eco-risk areas in Beijing would expand from the initial 24 to 110 km(2) if soil pH were to reduce by 0.5 units in anticipation.
[show abstract][hide abstract] ABSTRACT: We investigated how urban land uses influence soil accumulation of polycyclic aromatic hydrocarbons (PAHs) in the urban green spaces composed of different vegetative cover. How did soil properties, urbanization history, and population density affect the outcomes were also considered. Soils examined were obtained at 97 green spaces inside the Beijing metropolis. PAH contents of the soils were influenced most significantly by their proximity to point source of industries such as the coal combustion installations. Beyond the influence circle of industrial emissions, land use classifications had no significant effect on the extent of PAH accumulation in soils. Instead, the nature of vegetative covers affected PAH contents of the soils. Tree-shrub-herb and woodland settings trapped more airborne PAH and soils under these vegetative patterns accumulated more PAHs than those of the grassland. Urbanization history, population density and soil properties had no apparent impact on PAHs accumulations in soils of urban green space.
[show abstract][hide abstract] ABSTRACT: Transpiration patterns of Aesculus chinensis in relation to explanatory variables in the microclimatic, air quality, and biological phenomena categories were measured in Beijing, China using the thermal dissipation method. The highest transpiration rate measured as the sap flux density of the trees took place from 10:00 am to 13:00 pm in the summer and the lowest was found during nighttime in the winter. To sort out co-linearity, principal component analysis and variation and hierarchical partitioning methods were employed in data analyses. The evaporative demand index (EDI) consisting of air temperature, soil temperature, total radiation, vapor pressure deficit, and atmospheric ozone (O3), explained 68% and 80% of the hourly and daily variations of the tree transpiration, respectively. The independent and joint effects of EDI variables together with a three-variable joint effect exerted the greatest influences on the variance of transpiration rates. The independent effects of leaf area index and atmospheric O3 and their combined effect exhibited minor yet significant influences on tree transpiration rates.
Journal of Environmental Sciences 01/2012; 24(7):1278-87. · 1.77 Impact Factor