Effectiveness of conservation easements in agricultural regions

Conservation easements are a standard technique for preventing habitat loss, particularly in agricultural regions with extensive cropland cultivation, yet little is known about their effectiveness. I developed a spatial econometric approach to propensity‐score matching and used the approach to estimate the amount of habitat loss prevented by a grassland conservation easement program of the U.S. federal government. I used a spatial autoregressive probit model to predict tract enrollment in the easement program as of 2001 based on tract agricultural suitability, habitat quality, and spatial interactions among neighboring tracts. Using the predicted values from the model, I matched enrolled tracts with similar unenrolled tracts to form a treatment group and a control group. To measure the program's impact on subsequent grassland loss, I estimated cropland cultivation rates for both groups in 2014 with a second spatial probit model. Between 2001 and 2014, approximately 14.9% of control tracts were cultivated and 0.3% of treated tracts were cultivated. Therefore, approximately 14.6% of the protected land would have been cultivated in the absence of the program. My results demonstrate that conservation easements can significantly reduce habitat loss in agricultural regions; however, the enrollment of tracts with low cropland suitability may constrain the amount of habitat loss they prevent. My results also show that spatial econometric models can improve the validity of control groups and thereby strengthen causal inferences about program effectiveness in situations when spatial interactions influence conservation decisions.     

Implications of Macroalgal Isolation by Distance for Networks of Marine Protected Areas

The global extent of macroalgal forests is declining, greatly affecting marine biodiversity at broad scales through the effects macroalgae have on ecosystem processes, habitat provision, and food web support. Networks of marine protected areas comprise one potential tool that may safeguard gene flow among macroalgal populations in the face of increasing population fragmentation caused by pollution, habitat modification, climate change, algal harvesting, trophic cascades, and other anthropogenic stressors. Optimal design of protected area networks requires knowledge of effective dispersal distances for a range of macroalgae. We conducted a global meta‐analysis based on data in the published literature to determine the generality of relation between genetic differentiation and geographic distance among macroalgal populations. We also examined whether spatial genetic variation differed significantly with respect to higher taxon, life history, and habitat characteristics. We found clear evidence of population isolation by distance across a multitude of macroalgal species. Genetic and geographic distance were positively correlated across 49 studies; a modal distance of 50–100 km maintained F_ST < 0.2. This relation was consistent for all algal divisions, life cycles, habitats, and molecular marker classes investigated. Incorporating knowledge of the spatial scales of gene flow into the design of marine protected area networks will help moderate anthropogenic increases in population isolation and inbreeding and contribute to the resilience of macroalgal forests. Implicaciones del Aislamiento por Distancia de Macroalgas para Redes de Áreas Marinas Protegidas     

Connotation and principles of ecological compensation in water source reserve areas based on the theory of externality

Understanding the connotation and principles of ecological compensation in water source reserve areas is the basis and guarantee for establishing and improving the ecological compensation mechanism of water source reserve areas. First, this paper reviews the three stages of ecological compensation research progress. Based on the review, using the theory of externality, the ecological environment system of water source reserve areas is then analyzed. This paper argues that the connotation of ecological compensation in water source reserve areas is a kind of institutional arrangement, which is designed to internalize externalities. Finally, based on the understanding of the connotation of ecological compensation in water source reserve areas, five principles for establishing and improving the ecological compensation mechanism are proposed, including the principle of fairness and justice, the principle of equivalence of equality and responsibility, the principle of flexibility and effectiveness, the principle of “earmark funds, and implementation by law,” and the principle of government compensation supplemented with market compensation.     

Review of Pesticide Retention Processes Occurring in Buffer Strips Receiving Agricultural Runoff1

Arora, Kapil, Steven K. Mickelson, Matthew J. Helmers, and James L. Baker, 2010. Review of Pesticide Retention Processes Occurring in Buffer Strips Receiving Agricultural Runoff. Journal of the American Water Resources Association (JAWRA) 46(3):618-647. DOI: 10.1111/j.1752-1688.2010.00438.x Abstract: Review of the published results shows that the retention of the two pesticide carrier phases (runoff volume and sediment mass) influences pesticide mass transport through buffer strips. Data averaged across different studies showed that the buffer strips retained 45% of runoff volume (ranging between 0 and 100%) and 76% of sediment mass (ranging between 2 and 100%). Sorption (soil sorption coefficient, K_oc) is one key pesticide property affecting its transport with the two carrier phases through buffer strips. Data from different studies for pesticide mass retention for weakly (K_oc < 100), moderately (100 < K_oc < 1,000), and strongly sorbed pesticides (K_oc > 1,000) averaged (with ranges) 61 (0-100), 63 (0-100), and 76 (53-100) %, respectively. Because there are more data for runoff volume and sediment mass retention, the average retentions of both carrier phases were used to calculate that the buffer strips would retain 45% of weakly to moderately sorbed and 70% of strongly sorbed pesticides on an average basis. As pesticide mass retention presented is only an average across several studies with different experimental setups, the application of these results to actual field conditions should be carefully examined.     

Protected Area Safeguard Tree and Shrub Communities from Degradation and Invasion: A Case Study in Eastern Madagascar

Despite their prevalence in both developed and developing countries, there have been surprisingly few field assessments of the ecological effectiveness of protected areas. This study aimed to assess the effectiveness of a key protected area in eastern Madagascar, Ranomafana National Park (RNP). We established paired 100 × 4-m vegetation transects (400 m²) within RNP and in remnant forests in the park’s peripheral zone. In each 400-m² plot, all woody stems >1.5 cm in diameter at breast height were measured and identified to species. All species were also identified as native or non-native. We identified utilitarian species within all transects and they were sorted into use category. We calculated plot-level taxonomic biodiversity and functional diversity of utilitarian species; the latter was calculated by clustering the multivariate distances between species based on their utilitarian traits, and all metrics were tested using paired t-tests. Our results showed that there was significantly higher biodiversity inside RNP than in remnant forests and this pattern was consistent across all diversity metrics examined. Forests not located within the park’s boundary had significantly higher non-native species than within RNP. There was no statistically significant difference in functional diversity of utilitarian species inside RNP vs. remnant forests; however, the overall trend was toward higher diversity inside park boundaries. These findings suggested that RNP has been effective at maintaining taxonomic diversity relative to surrounding unprotected areas and restricting the spread of non-native plants. The results also suggested that low functional redundancy of forests outside of RNP might be of concern, because residents in surrounding villages may have few other substitutes for the services provided by species that are of critical importance to their livelihoods. This study highlights the challenges of trying to reconcile biodiversity conservation with human use of natural resources in economically poor, remote areas.     

Comparison of Function of Created Wetlands of Two Age Classes in Central Pennsylvania

Hydrogeomorphic (HGM) functional assessment models were used to assess whether function in created wetlands of two ages (1 year old and >12 years old) was equivalent to that of natural (reference) mainstem floodplain wetlands. Reference wetlands scored higher than both created age classes for providing energy dissipation and short-term surface water storage. Reference wetlands scored higher in maintaining native plant community and structure than 1-year-old sites, and 12-year-old wetlands scored higher than reference sites for providing vertebrate habitat structure. Analysis of individual model variables showed that reference wetlands had greater vegetative biomass and higher soil organic matter content than both created wetland age classes. Created wetlands were farther from natural wetlands and had smaller mean forest patch sizes within a 1-km-radius circle around the site than did the reference sites, indicating less hydrologic connectivity. Created wetlands also had less microtopographic variation than reference wetlands. The 1-year-old created sites were placed in landscape settings with greater land use diversity and road density than reference sites. The 12-year-old sites had a higher gradient and a higher percentage of their surrounding area in urban land use. These results show that the created wetlands were significantly structurally different (if not functionally so) from reference wetlands even after 12 years. The most profound differences were in hydrology and the characteristics of the surrounding landscape. More attention needs to be focused on placing created wetlands in appropriate settings to encourage proper hydrodynamics, eliminate habitat fragmentation, and minimize the effects of stressors to the site.     

新乡市地表水体HCHs和DDTs的分布特征及生态风险评价

为了解新乡市地表水中HCHs和DDTs的分布特征及生态风险,采集新乡市18个地表水样并测定其中HCHs和DDTs的含量,采用概率密度函数重叠面积法和安全阈值法评价了HCHs和DDTs的生态风险.结果表明,新乡市地表水中HCHs和DDTs的质量浓度范围分别为1.28~49.2 ng·L-1和0.42~12.3 ng·L-1,与世界各地的地表水中HCHs和DDTs残留质量浓度相比属于中等污染水平.异构体比值表明HCHs污染的主要来源是林丹的使用,而DDTs的残留来源于工业品DDTs的使用.生态风险评价基于DDD、γ-HCHs和p,p'-DDT的暴露浓度以及相应的毒性数据,概率密度函数重叠面积法和安全阈值法均表明了这3种有机氯农药中DDD的风险最大,其次是γ-HCHs,p,p'-DDT的生态风险最小;安全阈值法进一步表明DDD、γ-HCHs和p,p'-DDT超过影响10%水生生物的概率分别为10.2%、5.94%和0.01%.     

北方冬季农村供暖对PM2.5的影响及解决方案研究

为研究北方冬季农村供暖对PM2.5的影响,我们在北方的部分乡镇农村进行了为期一年半的调查走访,结果表明,北方冬季农村供暖用煤总量大,利用效率低,其生活用煤产生的烟尘总量相当于工业用煤的2.7倍,加之村落人口密集,室内通风条件差,故现有的供暖形式对人体健康危害很大。针对供暖方式的研究,我们提出了在农村推行集中供暖的方案。     

农村发展中水污染成因调查研究——以江苏省为例

在中国农村发展过程中,水环境污染已严重制约了当前农村经济的健康持续发展,探究农村地区水污染的成因,寻求解决污染的对策已十分迫切。本文在对江苏省农村水环境污染现状进行调查的基础上,运用AHP层次分析法分析现阶段江苏农村发展过程中水污染的形成机理,包括经济发展因素、社会公众因素、政策法规因素,并提出相关结论与建议。     

以淮安市为例研究中小城市噪声污染现状及趋势

收集2006-2010年淮安市各功能区环境噪声、交通噪声和区域环境噪声监测数据,分析中小城市环境噪声的污染状况,结果表明中小城市的噪声环境质量都有不同程度的好转,与大城市环境噪声比较,各类噪声都明显低于大城市的噪声污染,但随着城市和交通的改造与发展,第4类城市功能区夜间环境噪声有增加趋势。