Social-ecological Resilience of a Nuosu Community-linked Watershed, Southwest Sichuan, China

Farmers of the Nuosu Yi ethnic group in the Upper Baiwu watershed report reductions in the availability of local forest resources. A team of interdisciplinary scientists worked in partnership with this community to assess the type and extent of social-ecological change in the watershed and to identify key drivers of those changes. Here, we combine a framework for institutional analysis with resilience concepts to assess system dynamics and interactions among resource users, resources, and institutions over the past century. The current state of this system reflects a legacy of past responses to institutional disturbances initiated at the larger, national system scale. Beginning with the Communist Revolution in 1957 and continuing through the next two decades, centralized forest regulations imposed a mismatch between the scale of management and the scale of the ecological processes being managed. A newly implemented forest property rights policy is shifting greater control over the management of forest resources to individuals in rural communities. Collective forest users will be allowed to manage commodity forests for profit through the transfer of long-term leases to private contractors. Villagers are seeking guidance on how to develop sustainable and resilient forest management practices under the new policy, a responsibility returned to them after half a century and with less abundant and fewer natural resources, a larger and aggregated population, and greater influence from external forces. We assess the watershed’s current state in light of the past and identify future opportunities to strengthen local institutions for governance of forest resources

Reforestation Programs in Southwest China: Reported Success, Observed Failure, and the Reasons Why

Ever since the disastrous floods of 1998, the Chinese government has used the Natural Forest Protection and Sloping Land Conversion Programs to promote afforestation and reforestation as means to reduce runoff, control erosion, and stabilize local livelihoods. These two ambitious programs have been reported as large-scale successes, contributing to an overall increase in China’s forest cover and to the stated goals of environmental stabilization. A small-scale field study at the project level of the implementation of these two programs in Baiwu Township, Yanyuan County, Sichuan, casts doubt upon the accuracy and reliability of these claims of success; ground observations revealed utter failure in some sites and only marginal success in others. Reasons for this discrepancy are posited as involving ecological, economic, and bureaucratic factors. Further research is suggested to determine whether these discrepancies are merely local aberrations or represent larger-scale failures in reforestation programs

Is the Returning Farmland to Forest Program a Success? Three case studies from Sichuan

China\u27s tuigeng huanlin or “Returning Farmland to Forest” (RFFP) program has been widely praised as the world\u27s largest and most successful payment for ecosystem services program, as well as a major contributor to China\u27s dramatic increase in forest cover from perhaps as low as 8% in 1960 to about 21% today. By compensating rural households for the conversion of marginal farmland to forestland and financing the afforestation of barren mountainsides, the program, in addition to expanding forestland, aims to reduce soil erosion and alleviate poverty. This paper presents qualitative and quantitative studies conducted on the local implementation of RFFP in three diverse townships in Sichuan. We find the actual results to be more mixed than the official figures would indicate. Though there have been some positive results, we identify problems with site and species selection, compensation for land taken out of cultivation, shift of labor to off-farm activities, and monitoring of replanted sites, which challenge the ecological and economic impacts of these programs and reveal much of the effort of the program has been misdirected. We suggest that efforts are misplaced because of the top-down, panacea nature of the program, which in turn is a feature of Chinese bureaucratic management

Evaluation Criteria for Implementation of a Sustainable Sanitation and Wastewater Treatment System at Jiuzhaigou National Park, Sichuan Province, China

The administration of Jiuzhaigou National Park in Sichuan Province, China, is in the process of considering a range of upgrades to their sanitation and wastewater treatment systems. Their case history involves an ongoing series of engineering design flaws and management failures. The administration of the Park identified sustainability, environmental protection, and education goals for their sanitation and wastewater treatment system. To meet the goal of sustainability, environmental and economic concerns of the Park’s administration had to be balanced with socio-cultural needs. An advanced reconnaissance method was developed that identified reasons for previous failures, conducted stakeholder analysis and interviews, determined evaluation criteria, and introduced innovative alternatives with records of successful global implementations. This evaluation also helped the Park to better define their goals. To prevent future failures, the administration of the Park must commit to a balanced and thorough evaluation process for selection of a final alternative and institute effective long-term management and monitoring of systems. In addition, to meet goals and achieve energy efficient, cost-effective use of resources, the Park must shift their thinking from one of waste disposal to resource recovery. The method and criteria developed for this case study provides a framework to aid in the successful implementation of sanitation projects in both underdeveloped and developed areas of the world, incorporating socio-cultural values and resource recovery for a complex group of stakeholders

Efficacy of in situ and meteoric Be-10 mixing in fluvial sediment collected from small catchments in China

Using measurements of in situ and meteoric 10Be in fluvial sand to measure erosion rates, quantify soil loss, and trace sediment sources and sinks relies on the assumption that such sediment is well-mixed and representative of the upstream area. We test this assumption at 13 river junctions in three tributary watersheds (200–2500 km2) to the Mekong River, Yunnan, China, where human alteration of the landscape is significant and widespread. We find that two of the three watersheds mix well for in situ 10Be and none mix well for meteoric 10Be when considering the concentration of 10Be at the outlet compared to the area-weighted mean of headwater samples. We also assessed mixing at 13 river junctions by comparing the erosion rate-weighted isotopic concentration of sediment taken from tributaries upstream of a junction to the concentration in a sample taken downstream of the junction. With this metric, mixing is generally poor for both in situ and meteoric 10Be but is better for in situ 10Be than for meteoric 10Be (p \u3c 0.05). This is likely because in situ 10Be is measured in quartz, which is resilient to physical and chemical breakdown in river systems whereas meteoric 10Be is measured in grain coatings which can abrade and dissolve. Basins eroding faster (\u3e 100 mm/kyr) tend to mix better than slowly eroding basins. We find no evidence that agricultural land use in sampled basins affects sediment mixing downstream. Mixing improves with increased basin area (particularly \u3e 200 km2), increased sampling distance downstream from an upstream junction (\u3e 500 m), and increased difference in size between tributaries (one tributary \u3e 3 times larger than the other). The most important factor affecting mixing efficacy for both in situ and meteoric 10Be is the fraction of the basin area contributing to the downstream sample that does not contribute to the upstream samples. Junctions with \u3e 2% of the basin area unsampled by upstream samples tend not to mix as well. Our data suggest specific sampling location strategies (such as amalgamation) likely to improve the outcome of fluvial network analysis using cosmogenic nuclides

Agricultural Land Use Doubled Sediment Loads in Western China\u27s Rivers

Land use changes, such as deforestation and agricultural expansion, increase soil erosion on the scale of hillslopes and small drainage basins. However, the effects of these changes on the sediment load in rivers is poorly quantified, with a few studies scattered globally, and only 10 data points in the world\u27s most populous nation, China. At 20 different sites in western China, we compare contemporary fluvial sediment yield data collected daily over 4 to 26 years between 1945 and 1987 (median = 19 years) to long-term measures of sediment generation based on new isotopic measurements of in situ Be-10 (beryllium-10) in river sediments. We find that median sediment yield at these sites exceeds background sediment generation rates by a factor of two (from 0.13 to 5.79 times, median 1.85 times) and that contemporary sediment yield is statistically significantly different from long-term sediment generation rates (p \u3c 0.05). Agricultural land use is directly and significantly proportional to the ratio of contemporary sediment yield to long term sediment generation rates (Spearman correlation coefficient rho = 0.52, p \u3c 0.05). We support these findings by calculating erosion indices, which compare the delivery of meteoric Be-10 to each watershed with the export of meteoric Be-10 bound to riverine sediment. Erosion indices are also directly and significantly proportional to agricultural land use (rho = 0.58, p \u3c 0.05). Together, these data sets suggest that upstream agricultural land use has significantly increased sediment supply to rivers in western China, likely increasing turbidity and decreasing ecosystem services such as fisheries

Extracellular Pneumococcal Serine Proteases Affect Nasopharyngeal Colonization.

Streptococcus pneumoniae has evolved versatile strategies to colonize the nasopharynx of humans. Colonization is facilitated by direct interactions with host cell receptors or via binding to components of the extracellular matrix. In addition, pneumococci hijack host-derived extracellular proteases such as the serine protease plasmin(ogen) for ECM and mucus degradation as well as colonization. S. pneumoniae expresses strain-dependent up to four serine proteases. In this study, we assessed the role of secreted or cell-bound serine proteases HtrA, PrtA, SFP, and CbpG, in adherence assays and in a mouse colonization model. We hypothesized that the redundancy of serine proteases compensates for the deficiency of a single enzyme. Therefore, double and triple mutants were generated in serotype 19F strain EF3030 and serotype 4 strain TIGR4. Strain EF3030 produces only three serine proteases and lacks the SFP encoding gene. In adherence studies using Detroit-562 epithelial cells, we demonstrated that both TIGR4Δcps and 19F mutants without serine proteases or expressing only CbpG, HtrA, or PrtA have a reduced ability to adhere to Detroit-562 cells. Consistent with these results, we show that the mutants of strain 19F, which preferentially colonizes mice, abrogate nasopharyngeal colonization in CD-1 mice after intranasal infection. The bacterial load in the nasopharynx was monitored for 14 days. Importantly, mutants showed significantly lower bacterial numbers in the nasopharynx two days after infection. Similarly, we detected a significantly reduced pneumococcal colonization on days 3, 7, and 14 post-inoculations. To assess the impact of pneumococcal serine proteases on acute infection, we infected mice intranasally with bioluminescent and invasive TIGR4 or isogenic triple mutants expressing only CbpG, HtrA, PrtA, or SFP. We imaged the acute lung infection in real-time and determined the survival of the mice. The TIGR4lux mutant expressing only PrtA showed a significant attenuation and was less virulent in the acute pneumonia model. In conclusion, our results showed that pneumococcal serine proteases contributed significantly to pneumococcal colonization but played only a minor role in pneumonia and invasive diseases. Because colonization is a prerequisite for invasive diseases and transmission, these enzymes could be promising candidates for the development of antimicrobials to reduce pneumococcal transmission

Influence of topography and human activity on apparent in situ Be-10-derived erosion rates in Yunnan, SW China

In order to understand better if and where erosion rates calculated using in situ Be-10 are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ Be-10 in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin area = 46.5 km(2)). Erosion rates range from 12 to 209 mm kyr(-1) with an area-weighted mean of 117 +/- 49 mm kyr(-1) (1 standard deviation) and median of 74 mm kyr(-1). We observed a decrease in the relative influence of human activity from our steepest and least altered watershed in the north to the most heavily altered landscapes in the south. In the areas of the landscape least disturbed by humans, erosion rates correlate best with measures of topographic steepness. In the most heavily altered landscapes, measures of modern land use correlate with Be-10-estimated erosion rates but topographic steepness parameters cease to correlate with erosion rates. We conclude that, in some small watersheds with high rates and intensity of agricultural land use that we sampled, tillage and resultant erosion has excavated deeply enough into the regolith to deliver subsurface sediment to streams and thus raise apparent in situ Be-10-derived erosion rates by as much as 2.5 times over background rates had the watersheds not been disturbed