A GIS-based approach for assessing the regional conservation status of genetic diversity: an example from the southern Appalachians

Conserving genetic diversity requires an assessment of the distribution of genetic variants in relation to patterns of land use and environmental variation at a regional scale. This assessment requires a novel approach to integrating and analyzing the genetic and environmental data across spatial scales. To explore the integration of genetic data with other geospatial data sets, we developed a GIS-based approach for examining patterns of genetic diversity for several species of salamanders in southern Appalachians. The genetic data, from allozyme surveys in the genetics literature, were integrated into a GIS database along with related attributes including population identifications and spatial locations. Using existing geospatial data, we classified sample locations as being either protected from anthropogenic disturbance (e.g., National Parks, Wilderness Areas) or as unprotected (e.g., private lands, multiple-use lands in National Forests). We used multidimensional scaling of allelic frequencies and contributions of populations to interpopulation differences in allelic richness to determine which populations had genetic characteristics most different from other populations in the sample. Measures of genetic differentiation were integrated into the GIS database to facilitate spatial analysis and visualization of the indices in relation to land use. This approach was useful for both identification of populations with components of genetic variation that were not well represented at protected sites and for identifying areas of species distributions where more genetic sampling would be necessary to make informed management decisions. Our approach could be readily adapted for use by managers and geneticists working with other species and types of genetic markers.     

苏打盐碱地稻田养鱼

苏打盐碱地主要分布在我国东北地区,是松辽平原农业综合开发的重点对象之一。作者以吉林省西部大安市叉干镇科技示范区为例,介绍了苏打盐碱地井灌稻田养鱼开发的生态效益及关键技术。     

Effects of land use on concentrations of metals in surface soils and ecological risk around Guanting Reservoir,China

It is accepted that the historical routine use of agrochemicals may have resulted in undesirable concentrations of metals in the environment. To investigate and assess the effects of land use on concentrations of heavy metals around the Guanting Reservoir in China, 52 surface soil samples (depth of 2–10 cm) were taken from areas where four types of land use were practiced (including arable land, woodland, bare land, orchard land). The metals and metalloids (As, Cr, Ni, Cu, Zn, Cd, and Pb) were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Significant accumulation of As, Cd, and Cr was found in soils of arable land. Based on correlation and cluster analysis, it can be concluded that Cd and Zn originate mainly from phosphate fertilizer, Pb from the use of insecticides, fertilizers, and sewage sludge as well as air deposition, and Cu from copper-based fungicides, while As, Ni and Cr might come from parent soil material. According to an ecological risk analysis of metals based on the ecological index suggested by Hakanson, the four types of land can be ranked by severity of ecological risk as follows: arable land > woodland > bare land > orchard land, with a high ecological risk of Cd for all four types. Management measures for land use planners for avoiding water, soil, and sediment pollution caused by metals around the Guanting Reservoir are presented.     

Effect of photo-biodegradation and biodegradation on the biogeochemical cycling of dissolved organic matter across diverse surface water bodies

The objective of this research was to quantify the temporal variation of dissolved organic matter(DOM) in five distinct waterbodies in watersheds with diverse types of land use and land cover in the presence and absence of sunlight. The water bodies were an agricultural pond, a lake in a forested watershed, a man-made reservoir, an estuary, and a bay. Two sets of samples were prepared by dispensing unfiltered samples into filtered samples in 1:10 ratio(V/V). The first set was exposed to sunlight(10 hr per day for 30 days) for examining the combined effect of photo-biodegradation, while the second set was stored in dark for examining biodegradation alone. Spectroscopic measurements in tandem with multivariate statistics were used to interpret DOM lability and composition. The results suggest that the agricultural pond behaved differently compared to other study locations during degradation experiments due to the presence of higher amount of microbial humic-like and protein-like components derived from microbial/anthropogenic sources. For all samples, a larger decrease in dissolved organic carbon(DOC) concentration(10.12% ±9.81% for photo-biodegradation and 6.65% ± 2.83% for biodegradation) and rapid transformation of DOM components(i.e., terrestrial humic-like components into microbial humic and protein-like components) were observed during photo-biodegradation experiments.Results suggest that sunlight facilitated DOM biodegradation, resulting in simpler recalcitrant molecules regardless of original composition. Overall, it was found that combined effects of light and bacteria are more efficient than bacterial effects alone in remineralizing and altering DOM, which highlights the crucial importance of sunlight in transforming aquatic DOM.     

格网尺度下延安市生态服务价值时空演变格局与分异特征——基于退耕还林工程的实施背景

在退耕还林工程背景下,以退耕还林实施后生态效果较显著的延安市为研究对象,基于解译的三期影像数据,通过土地利用转移矩阵,在2 km×2 km的格网尺度下测算延安市不同土地利用类型的生态服务价值（ESV）,并结合空间探索性数据分析,探讨ESV的不同土地利用类型转移的时间变化特征及空间转移的关联性和异质性。延安市的实证分析显示：（1）1990-2015年间,ESV的增减主要发生在耕地、林地和草地之间,林地和草地ESV合计转入21.29亿元,且转入量主要发生在退耕还林工程实施之后;（2）生态服务功能主要由林地和草地提供,ESV的时间变化经历了先下降后上升的过程,退耕还林工程的实施促进ESV的增长,2001-2015年间增长了5.34%;（3）空间探索性分析显示,ESV在格网尺度下呈现出显著的“南高北低”分布格局,并在空间上表现出正向的集聚性和依存性,ESV的高高集聚和低低集聚效果比较明显,并且高高集聚区与林地、草地的空间分布相吻合,低低集聚区与耕地、城乡建设用地的空间分布相吻合。整体而言,延安市土地利用类型转移和ESV的增减变化与推行退耕还林工程在时间上呼应、在空间上匹配,政府主导的退耕还林工程对生态环境恢复与保护起到显著的积极作用。因此,对于不同土地利用类型的生态服务功能,以耕地为主的北部地区应在基本农田保护制度基础上,注重农业生产与生态效益平衡,而林草资源丰富的南部地区则继续发挥生态屏障的调节作用。     

Influence of new generic frequencies on the QRA calculations for land use planning purposes in Walloon region (Belgium)

In Europe, the article 12 of the “Seveso” Directive focuses on land use planning (LUP) around major hazard plants and imposes to keep a sufficient distance between a major hazard plant and populated areas. In Belgium, the LUP is treated at the regional level. The regional authority defines the policy and manages the LUP according to the quantified risk. The quantified external risk, around each Seveso company in the Walloon Region, is assessed by a unique technical expert, the Faculté Polytechnique de Mons, by means of a full probabilistic approach (QRA). This QRA methodology uses accident generic frequencies published by the Flemish Region (Aminal, 2004). In 2009-2010, the quantification of the external risk of the 90 walloon Seveso plants will be completed, based on this set of generic frequencies. However, the Flemish Region recently published a new set of generic frequencies (LNE, 2009), which, in some cases, are quite different of the previous ones for some equipment. This paper discusses the influence of the new frequency data on the quantified risk. An overview of the changes induced by the new set of data will be presented, as well as their impact on the already defined "consultation zones" in which decisions are made concerning the compatibility of the land use and the intensity of risk.     

Is everyone hot in the city? Spatial pattern of land surface temperatures,land cover and neighborhood socioeconomic characteristics in Baltimore,MD

Urban heat island effect refers to the phenomenon that ambient air and surface temperatures in urban areas are several degrees higher than surrounding rural areas. Higher temperatures not only impact the comfort of urban dwellers, but also increase energy use, ozone production, and the risk of death for humans in a heat wave. Our research focuses on the variation in land surface temperature in the Gywnns Fall Watershed, Maryland. We found that land surface temperature is highly variable spatially, resulting in "hotspots" within the heat island. We further explore how this temperature variation relates to social factors on the scale of the census-based block group. We show that land surface temperature is statistically higher in block groups that are characterized by low income, high poverty, less education, more ethnic minorities, more elderly people and greater risk of crime. These variables were mapped to evaluate the spatial relationship of land surface temperatures to social factors. This spatially explicit approach facilitates identification of specific areas to prioritize for heat prevention and intervention efforts. We demonstrate, through an exercise, how incorporating data on land surface temperature and social factors into heat intervention strategies could contribute to efficient allocation of limited resources and services. The exercise also indicates where heat prevention efforts, such as tree-planting programs, are most needed to help reduce heat exposure and moderate the urban heat island effect.     

Lake area changes in the middle Yangtze region of China over the 20th century

The Jianghan Plain and the Dongting lake area, located in the middle reaches of the Yangtze River are famous for their abundant freshwater lakes. The lakes have undergone changes in size and number over thousands of years due to natural causes and human activities. The 20th century particularly, witnessed dramatic changes in the freshwater resources of this region. This paper traces and analyzes lake evolution in the middle reaches of the Yangtze River over the past century. Lakes greater than 0.1 km(2) in size are mapped using Geographic Information System. Data is acquired and integrated from drainage network maps, relief maps, historical maps and remotely sensed images for different time periods. The results indicate that while there has been little change in the number of lakes over the past century, the lake area has experienced a dramatic decrease of 58.06%. The paper also examines the natural processes and human activities that may have contributed to the decrease in lake area. The results show that the decrease in total lake area appears to coincide with periods of rapid land reclamation in the middle reaches of the Yangtze River. Moreover, uncontrolled land reclamation activities can create an increase in sediment deposition in lakes thereby further reducing the lake size. Reduction of the lake area directly affects flood-control and has a negative ecological impact on the environment and on human life and property.     

Shifting cultivation, forest fallow, and externalities in ecosystem services: Evidence from the Eastern Amazon

This study examines the value of fallow ecosystem services in shifting cultivation, including hydrological externalities that may affect other farms. Using farm-level survey data from the Brazilian Amazon, I estimate a production function to assess the value of forest fallow and test whether it provides local externalities to agricultural production. Soil quality controls, instrumental variables, and spatial econometric approaches help address endogeneity issues. I use GIS data on external forest cover at the farm level and model the hydrological externality as an upstream-to-downstream process. The estimated parameters indicate that fallow contributes significantly to productivity both on farm and downstream. In addition, most farms allocate sufficient land to fallow, accounting for both the value of hydrological spillovers and the opportunity cost of land left out of cultivation. These results suggest that farming communities may have some self-interest in preserving forest cover locally—a finding that may bolster policy efforts aimed at conserving tropical forests for their global public goods.     

Evaluating weather effects on interannual variation in net ecosystem productivity of a coastal temperate forest landscape: A model intercomparison

Forest productivity is strongly affected by seasonal weather patterns and by natural or anthropogenic disturbances. However weather effects on forest productivity are not currently represented in inventory-based models such as CBM-CFS3 used in national forest C accounting programs. To evaluate different approaches to modelling these effects, a model intercomparison was conducted among CBM-CFS3 and four process models (ecosys, CN-CLASS, Can-IBIS and 3PG) over a 2500 ha landscape in the Oyster River (OR) area of British Columbia, Canada. The process models used local weather data to simulate net primary productivity (NPP), net ecosystem productivity (NEP) and net biome productivity (NBP) from 1920 to 2005. Other inputs used by the process and inventory models were generated from soil, land cover and disturbance records. During a period of intense disturbance from 1928 to 1943, simulated NBP diverged considerably among the models. This divergence was attributed to differences among models in the sizes of detrital and humus C stocks in different soil layers to which a uniform set of soil C transformation coefficients was applied during disturbances. After the disturbance period, divergence in modelled NBP among models was much smaller, and attributed mainly to differences in simulated NPP caused by different approaches to modelling weather effects on productivity. In spite of these differences, age-detrended variation in annual NPP and NEP of closed canopy forest stands was negatively correlated with mean daily maximum air temperature during July-September (T_amax) in all process models (R² = 0.4-0.6), indicating that these correlations were robust. The negative correlation between T_amax and NEP was attributed to different processes in different models, which were tested by comparing CO₂ fluxes from these models with those measured by eddy covariance (EC) under contrasting air temperatures (T_a). The general agreement in sensitivity of annual NPP to T_amax among the process models led to the development of a generalized algorithm for weather effects on NPP of coastal temperate coniferous forests for use in inventory-based models such as CBM-CFS3: NPP′ = NPP − 57.1 (T_amax − 18.6), where NPP and NPP′ are the current and temperature-adjusted annual NPP estimates from the inventory-based model, 18.6 is the long-term mean daily maximum air temperature during July-September, and T_amax is the mean value for the current year. Our analysis indicated that the sensitivity of NPP to T_amax was nonlinear, so that this algorithm should not be extrapolated beyond the conditions of this study. However the process-based methodology to estimate weather effects on NPP and NEP developed in this study is widely applicable to other forest types and may be adopted for other inventory based forest carbon cycle models.