Impacts of climate warming on reindeer herding require new land-use strategies

Climate in the Arctic has warmed at a more rapid pace than the global average over the past few decades leading to weather, snow, and ice situations previously unencountered. Reindeer herding is one of the primary livelihoods for Indigenous peoples throughout the Arctic. To understand how the new climate state forces societal adaptation, including new management strategies and needs for preserved, interconnected, undisturbed grazing areas, we coupled changes in temperature, precipitation, and snow depth recorded by automatic weather stations to herder observations of reindeer behaviour in grazing areas of the Laevas Sámi reindeer herding community, northern Sweden. Results show that weather and snow conditions strongly determine grazing opportunities and therefore reindeer response. We conclude that together with the cumulative effects of increased pressures from alternative land use activities, the non-predictable environmental conditions that are uniquely part of the warming climate seriously challenge future reindeer herding in northern Sweden.     

Assessing Biotic Integrity of Streams: Effects of Scale in Measuring the Influence of Land Use/Cover and Habitat Structure on Fish and Macroinvertebrates

/ Fish and macroinvertebrate assemblage composition, instream habitat features and surrounding land use were assessed in an agriculturally developed watershed to relate overall biotic condition to patterns of land use and channel structure. Six 100-m reaches were sampled on each of three first-order warm-water tributaries of the River Raisin in southeastern Michigan. Comparisons among sites and tributaries showed considerable variability in fish assemblages measured with the index of biotic integrity, macroinvertebrate assemblages characterized with several diversity indexes, and both quantitative and qualitative measurements of instream habitat structure. Land use immediate to the tributaries predicted biotic condition better than regional land use, but was less important than local habitat variables in explaining the variability observed in fish and macroinvertebrate assemblages. Fish and macroinvertebrates appeared to respond differently to landscape configuration and habitat variables as well. Fish showed a stronger relationship to flow variability and immediate land use, while macroinvertebrates correlated most strongly with dominant substrate. Although significant, the relationships between instream habitat variables and immediate land use explained only a modest amount of the variability observed. A prior study of this watershed ascribed greater predictive power to land use. In comparison to our study design, this study covered a larger area, providing greater contrast among subcatchments. Differences in outcomes suggests that the scale of investigation influences the strength of predictive variables. Thus, we concluded that the importance of local habitat conditions is best revealed by comparisons at the within-subcatchment scale. KEY WORDS: Stream; Biomonitoring; Land use; Scale; Habitat; Fish; Macroinvertebrates     

尉犁县土地开发对塔里木河中下游生态环境的影响及其保护对策分析

阐明了土地开发对塔里木河中下游生态环境的影响,研究分析其原因并提出了相应的对策。     

土地开发利用中的环境影响预测及其保护措施

随着我国工业的发展和人口不断增加,粮食问题越显得更加重要,开发土地是解决这一问题的重要途径之一。但是土地资源的开发是一项复杂的系统工程,土地开发利用的过程,也是自然再生产的过程,在优越的条件下土壤会向着肥沃的方面发展,否则会向着相反的方面转化。以最大的可能性和最稳妥的管理措施,避免土地开发后对环境产生的不利影响,以保持农业持续稳定发展。     

Remote Sensing Change Detection and Process Analysis of Long-Term Land Use Change and Human Impacts

This study investigates environmental change over a 30-year period and attempts to gain a better understanding of human impacts on an arid environment and their consequences for regional development. Multi-temporal remotely sensed imagery was acquired and integrated to establish the basis for change detection and process analysis. Land cover changes were investigated in two categories, namely categorical change using image classification and quantitative change using a vegetation index. The results show that human-induced land cover changes have been minor in this remote area. However, the pace of growth of human-induced change has been accelerating since the early 1990s. The analysis of the multi-temporal vegetation index also shows no overall trend of rangeland deterioration, although local change of vegetation cover caused by human activities was noticeable. The results suggest that the current trend of rapid growth may not be sustainable and that the implementation of effective counter-measures for environmentally sound development is a rather urgent matter.     

Mapping Grazing-Induced Degradation in a Semi-Arid Environment: A Rapid and Cost Effective Approach for Assessment and Monitoring

Improved techniques for measuring and monitoring the state of biodiversity are required for reporting on national obligations to international and regional conservation institutions. Measuring the extent of grazing-related degradation in semi-arid ecosystems has proved difficult. Here we present an accurate and cost-effective method for doing this, and apply it in a South African semi-arid region that forms part of a globally significant biodiversity hotspot. We grouped structurally and functionally similar vegetation units, which were expert-mapped at the 1:50,000 scale, into four habitat types, and developed habitat-specific degradation models. We quantified degradation into three categories, using differences between dry and wet season values of the Normalized Difference Vegetation Index (NDVI) for the three succulent karoo habitats, and the difference between maximum and mean NDVI values for the subtropical thicket habitat. Field evaluation revealed an accuracy of 86%. Overall, degradation was high: 24% of the study area was modeled as severely degraded, and only 9% as intact. Levels of degradation were highest for bottomland habitats that were most exposed to grazing impacts. In sharp contrast to our methods, a widely used, broad-scale and snapshot assessment of land cover in South Africa was only 33% accurate, and it considerably underestimated the extent of severely degraded habitat in the study area. While our approach requires a multidisciplinary team, and in particular expert knowledge on the characteristics and spatial delimitation of vegetation types, it is repeatable, rapid, and relatively inexpensive. Consequently, it holds great promise for monitoring and evaluation programs in semi-arid ecosystems, in Africa, and beyond.     

Constrained Choice and Ethical Dilemmas in Land Management: Environmental Quality and Food Safety in California Agriculture

As environmental and conservation efforts increasingly turn towards agricultural landscapes, it is important to understand how land management decisions are made by agricultural producers. While previous studies have explored producer decision-making, many fail to recognize the importance of external structural influences. This paper uses a case study to explore how consolidated markets and increasing corporate power in the food system can constrain producer choice and create ethical dilemmas over land management. Crop growers in the Central Coast region of California face conflicting demands regarding environmental quality and industry imposed food safety standards. A mail survey and personal interviews were used to explore growers’ perceptions and actions regarding these demands. Results indicate that in many cases growers face serious ethical dilemmas and feel pressured by large processing and retail firms to adopt measures they find environmentally destructive and unethical. Future strategies to address environmental issues on agricultural landscapes should consider the economic constraints producers face and the role of large firms in creating production standards.     

基于证据权重法的呼伦贝尔地区人为草原火险空间预测

应用证据权重法结合GIS空间分析,研究了呼伦贝尔地区人为草原火险。利用证据权重法定量化地分析了与人类活动密切相关的5个因子(乡村人口密度、载畜密度、居民点分布、城镇分布、公路网)与草原火点空间分布的关系,并建立了呼伦贝尔草原火险预测模型,据此在ARCVIEW的WofE扩展模块下生成一幅草原火险预测专题图,并将研究区划分为高、中、低三类风险区。研究表明:(1)呼伦贝尔草原火灾火点的空间分布与人类活动关系密切,尤其是乡村人口密度、公路网与居民点分布这三个因子,权重分别为0.5191,0.1945,0.2864;(2)证据权重法可以客观定量地表现出草原火险与人类活动的关系,因而可为草原火灾风险管理提供决策支持。     

PBDEs in the supralittoral environment: the sandhopper Talitrus saltator (Montagu) as biomonitor?

In this study we evaluated the use of Talitrus saltator as biomonitor of polybrominated diphenyl ethers (PBDEs) contamination of the supralittoral zone of Mediterranean sandy shores, an area characterized by a strong input of contaminants but not yet investigated about the presence of these pollutants. We detected the presence of twenty PBDE congeners in amphipods and sand samples collected along the Tyrrhenian coast of central Italy. Eight congeners were detected in all samples. Among them, the BDE-209 was the most abundant in both amphipods and sand samples followed by BDE-99, BDE-153 and BDE-47 in animals, and BDE-99, BDE-47 and BDE-100 in sediment. The ΣPBDEs in amphipods was higher (on the average 2.5-5-fold) than in sand for almost the totality of congeners detected and each sampling site, suggesting the good capacity of sandhoppers to accumulate these pollutants. Moreover statistical analysis revealed significant differences in PBDE concentrations recorded in tissues of T. saltator among sampling sites. Therefore our results suggested the possible utilization of T. saltator as a biomonitor of PBDE contamination of the supralittoral zone of Mediterranean sandy shores.