High sensitivity of montane bird communities to habitat disturbance in Peninsular Malaysia

Over the past few decades, the montane forests of Peninsula Malaysia have been severely impacted by the cultivation of exotic crops and urban sprawl. To guide conservation initiatives, montane bird communities were studied to determine their response along a disturbance gradient with the aim of identifying key factors influencing their distribution. Habitat types surveyed included primary and secondary montane forests, a tea plantation, rural, and urban areas in Cameron Highlands and Fraser’s Hill. Response variables included species richness and density quantified via point counts and mistnet surveys. Explanatory variables measured were related to vegetation structure, food abundance and land-use cover. Estimated ‘true’ species richness was higher for pristine and minimally disturbed sites, lower in tea plantation and lowest in heavily developed town centres. Nonmetric multidimensional scaling revealed that both vegetation structure (e.g. canopy density) and land-use cover (e.g. proportion of forest cover) influence species distribution; certain invasive lowland birds were tolerant of extreme development and native montane birds, in general, endured only slight habitat disturbances. A simulation indicated that montane forest dependant species richness started to decline when more than 20% of the canopy cover was lost. Less than a third of the species richness remained when more than 40% of the canopy cover was cleared. The logistic regression model suggested that sensitive species nested lower, were restricted to montane habitats and foraged in mid or high canopy. The dominance of lowland invasives in highly developed urban sites reveals that homogenisation of bird communities can occur even at higher altitudes (>1400 m a.s.l.). The results indicated that native montane birds communities are sensitive to habitat loss and degradation. Thus, any development in the highlands must proceed with minimal disturbance to montane forests, of which, keeping the canopy cover intact should be a crucial consideration.     

Lowland rainforest avifauna and human disturbance: persistence of primary forest birds in selectively logged forests and mixed-rural habitats of southern Peninsular Malaysia

We compared the composition and structure of primary forest avifauna among primary forests, selectively logged forests and mixed-rural areas (e.g. villages and agricultural areas) of Peninsular Malaysia. We found that forests that were selectively logged at least 30 years ago contained only 73-75% of the 159 species of extant primary forest birds, with an increased proportion of dominant species. We estimated that only 28-32% of the primary forest species utilized the mixed-rural habitat, and that the number of species that bred in the agricultural landscapes might be even lower. The microhabitat of different species most affected their vulnerability to disturbance. Most small, arboreal frugivores and omnivores, and insectivores that fed from tree trunks, showed greater persistence in the mixed-rural habitat than ground dwelling bird species, which were affected most by disturbance. Resource abundance and variables that were closely related to forest disturbance such as the density of large trees, density of dead trees, canopy cover density and shrub volume influenced the distribution of the primary forest birds. Large primary forest reserves and a revision of short-cycle logging regimes (ca. 30 years) are needed if we are to conserve the lowland rainforest avifauna of Peninsular Malaysia and other parts of Southeast Asia.     

天山北麓土地利用与土地退化的时空特征探析

研究天山北麓土地利用/覆被变化过程中的土地退化现象,有利于监测新垦绿洲的环境演变过程。采用1990年、2000年2010年3期遥感影像为基础数据,选取土地利用变化幅度、动态度、土地利用强度指数和LUCC动态变化趋势指数4个指标,并结合转移矩阵,对该地区20 a来的土地利用/覆被变化时空特征及土地退化现象进行综合分析。1990—2010年,研究区耕地和城乡居民工矿用地所占比例持续上升,分别增加了91.05%和60.19%。草地和冰川/永久积雪面积则大幅减少,分别下降了15.45%和28.97%。通过转移矩阵发现,草地和永久冰川退化成荒漠的趋势明显。各土地利用类型中以草地的土地利用变化强度指数最高,达－0.5056%,耕地次之,为0.4091%。研究区土地利用类型间主要转移方向为:草地和冰川/永久积雪转化为荒漠,荒漠和草地转化为耕地,荒漠与草地间相互转化,盐碱地面积得到控制,但向荒漠转化的趋势凸显,永久冰川的消融明显加剧,草地持续退化,研究区生态环境恶化趋势明显。     

Land Use and Soil Organic Carbon in China’s Village Landscapes

Village landscapes, which integrate small-scale agriculture with housing, forestry, and a host of other land use practices, cover more than 2 million square kilometers across China. Village lands tend to be managed at very fine spatial scales (≤ 30 m), with managers both adapting their practices to existing variation in soils and terrain (e.g., fertile plains vs. infertile slopes) and also altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Relationships between fine-scale land management patterns and soil organic carbon (SOC) in the top 30 cm of village soils were studied by sampling soils within fine-scale landscape features using a regionally weighted landscape sampling design across five environmentally distinct sites in China. SOC stocks across China’s village regions (5 Pg C in the top 30 cm of 2 × 10 6 km 2 ) represent roughly 4% of the total SOC stocks in global croplands. Although macroclimate varied from temperate to tropical in this study, SOC density did not vary significantly with climate, though it was negatively correlated with regional mean elevation. The highest SOC densities within landscapes were found in agricultural lands, especially paddy, the lowest SOC densities were found in nonproductive lands, and forest lands tended toward moderate SOC densities. Due to the high SOC densities of agricultural lands and their predominance in village landscapes, most village SOC was found in agricultural land, except in the tropical hilly region, where forestry accounted for about 45% of the SOC stocks. A surprisingly large portion of village SOC was associated with built structures and with the disturbed lands surrounding these structures, ranging from 18% in the North China Plain to about 9% in the tropical hilly region. These results confirmed that local land use practices, combined with local and regional variation in terrain, were associated with most of the SOC variation within and across China’s village landscapes and may be an important cause of regional variation in SOC.     

Impact of Land Use and Land Cover Changes on Organic Carbon Stocks in Mediterranean Soils (1956–2007)

During the last few decades, land use changes have largely affected the global warming process through emissions of CO₂. However, C sequestration in terrestrial ecosystems could contribute to the decrease of atmospheric CO₂ rates. Although Mediterranean areas show a high potential for C sequestration, only a few studies have been carried out in these systems. In this study, we propose a methodology to assess the impact of land use and land cover change dynamics on soil organic C stocks at different depths. Soil C sequestration rates are provided for different land cover changes and soil types in Andalusia (southern Spain). Our research is based on the analysis of detailed soil databases containing data from 1357 soil profiles, the Soil Map of Andalusia and the Land Use and Land Cover Map of Andalusia. Land use and land cover changes between 1956 and 2007 implied soil organic C losses in all soil groups, resulting in a total loss of 16·8 Tg (approximately 0·33 Tg y⁻¹). Afforestation increased soil organic C mostly in the topsoil, and forest contributed to sequestration of 8·62 Mg ha⁻¹ of soil organic C (25·4 per cent). Deforestation processes implied important C losses, particularly in Cambisols, Luvisols and Vertisols. The information generated in this study will be a useful basis for designing management strategies for stabilizing the increasing atmospheric CO₂ concentrations by preservation of C stocks and C sequestration. Copyright © 2012 John Wiley & Sons, Ltd.     

土地利用/土地覆被变化环境效应研究

土地利用/土地覆被变化（LUCC）是全球变化研究的重要方向之一。土地利用/土地覆被变化的环境效应问题一向都是研究的重点。结合近年来土地利用/土地覆被变化在环境方面的一些研究进展,综述了土地利用/土地覆被变化对全球气候、大气质量以及区域土壤、水文和生物多样性的影响,并提出了黄土高原地区土地利用/土地覆被变化研究亟需解决的一些问题。     

1990-2015年红碱淖地区土地利用/土地覆盖与景观格局的时空演变

[目的]研究近25 a红碱淖地区的土地利用景观格局演变,为西北矿区生态环境保护、煤炭的绿色开采以及沙漠湖泊的环境管理和决策提供基础数据和科学依据.[方法]选取1990,2000,2005,2010和2015年5期Landsat TM/ETM+/OLI影像,利用遥感、地理信息系统技术和地理数学统计方法定量分析红碱淖地区土地利用/土地覆盖的动态变化和景观格局的演变特征.[结果] 1990-2015年,红碱淖地区的耕地和沙地面积分别增加了3.56％和21.87％,林草地和水体的面积分别减少了23.85％和2.25％,区域内水体和林草地退化严重,林草地主要转化为沙地和耕地;景观指数中,平均斑块面积减少,斑块总数、形状指数和多样性指数增加,景观破碎化程度加大,景观类型增加.[结论]上游修建水库和开采地表水使湖泊面积减少,退耕还林工程使得林草地面积增加等人为因素是影响红碱地区域景观格局变化的主要驱动因素.     

内蒙古自治区呼和浩特市1990-2010年景观格局变化及其驱动力

[目的]探究内蒙古自治区呼和浩特市景观格局的变化与驱动因素,以期为研究区经济社会可持续发展和区域水资源可持续利用提供理论支撑。[方法]利用1990,2000和2010年的3期土地利用类型遥感影像,运用ArcGIS及Fragstats景观分析软件,并结合景观生态学的分析方法,对内蒙古自治区呼和浩特市1990-2010年土地利用/覆被和景观格局变化进行分析。[结果]①研究区近20 a土地利用类型变化明显。耕地和林地面积增加,草地面积减少,而水体面积总体保持一致,但呈现先减少后增加的变化过程。②景观结构多样性增加,类型斑块数增加,破碎化程度加剧。③研究区土地利用/覆被和景观格局变化是人为因素和气候因素共同作用的结果,第1主成分和第2主成分为人为因素,第3主成分是自然因素。3个主成分对研究区土地利用和景观格局变化贡献率分别为51.34%,23.49%,10.90%。[结论]研究区土地利用和景观格局变化主要是人为活动中的耕地面积、人口数量、GDP、一产产值和气候因素中的降雨因素所致;自然因素贡献不大,人为因素中政策因素影响更加直接。     

Spatial Assessment of Land Degradation Risk for the Okavango River Catchment,Southern Africa

The Okavango catchment in southern Africa is subject to environmental as well as socio‐economic transformation processes such as population growth and climate change. The degradation of soil and vegetation by deforestation and overgrazing is one of the downsides of this development, reducing the capacity of the land to provide ecosystem functions and services. In this study, climate simulations are brought together with secondary socioeconomic, pedologic and remote‐sensing data in a GIS‐based assessment of the factors commonly associated with land degradation risk. A high resolution overview is provided for decision‐makers and stakeholders in the region by identifying priority intervention areas where a long‐term decline in ecosystem function and land productivity is most likely to occur. The approach combines 19 risk factors into seven individual ratings for topography, landcover, soil, demography, infrastructure, livestock pressure and climate. These ratings are then weighted and combined into an integrated degradation risk index (DRI). The results show that the land degradation risk is quite heterogeneously distributed in the study area and caused by different factors. Three hot‐spots are identified and compared, one of which is in the far northwestern part of the catchment, one around the local center Rundu and one on the outskirts of the Okavango Delta. We conclude that the approach is suitable to give an overview on degradation risk in the study area, although the classification process is a crucial procedure that should be standardized for further research. Copyright © 2015 John Wiley & Sons, Ltd.     

Changes in Physical Properties of Soils with Land Use Time in the Brazilian Savanna Environment

Soils from central Brazil have been intensively used over the last decades because of the rapid conversion of savannas ( Cerrado ) into corn/soybean fields. The objective of this work is to study modifications in the physical properties of soils in the Rio Verde watershed, as a function of the land use time for agriculture, determined from classification of Landsat satellite images between 1980 and 2010. Soil samples were collected at surface (0–20 cm) and subsurface (20–40 cm) horizons for the different classes of land use time (<10, 10–20, 20–30, and >30 years). The following physical properties were measured: bulk density (BD), air permeability (K_a), penetration resistance (PR), microporosity (MI), macroporosity (MA), and total porosity (TP). Results showed a strong expansion with time of agriculture that occupied 35·3% (1980), 37·4% (1990), 51·3% (2000), and 60·9% (2010) of the watershed area. When properties were compared with those from the reference areas (preserved soils under native vegetation), significant differences were observed for all the physical attributes of soils for a land use time higher than 20 years. Overall, BD and PR increased with land use time, and the opposite was verified for K_a, MA, and TP. Some physical properties presented values (e.g., 1·54 g cm⁻³ for BD and 0.06 cm³ cm⁻³ for MA) close to the critical ones reported to affect crop development, but they were not still impacting on local soybean yield. Copyright © 2013 John Wiley & Sons, Ltd.     

1980-2020年洞庭湖流域土地利用变化及其碳效应

[目的] 探查粮食主产区土地利用变化规律及其碳效应,为土地利用结构调整及低碳经济发展提供依据。[方法] 基于1980,2000,2020年3期土地利用现状数据,在网格采样法、土地利用动态度模型、碳排放系数法以及空间自相关分析模型支持下,揭示1980年以来洞庭湖流域土地利用变化规律及其碳效应的空间异质性特征。[结果] ①洞庭湖流域土地利用阶段性变化。1980—2000年综合动态度为0.02%,其中动态度最大的是建设用地,未利用地次之。2000—2020年综合动态度增至0.18%,建设用地面积增长加快。②净碳效应表现为碳汇,但由1980年的5.93×10⁷ t下降到2020年2.82×10⁷ t,而由土地利用变化引起的碳效应呈现碳排放变化量大于碳汇变化量特点,并导致净碳排放量增加了6.08×10⁵ t,且空间上净碳排放相对高值区呈“H”型分布特点,低值区逐渐扩张。③洞庭湖流域集水小区净碳排放的空间自相关性特征显著。1980—2000年主要聚集类型为高—高型和低—低型,低—高型分布零散,2000—2020年高—高型分布更加集中连片,低—低型主要在湘江流域北部。[结论] 在洞庭湖流域,应坚持“碳增汇,碳减排”定位,保持林地的碳汇稳定状态,科学引导高碳排放土地的开发利用,并依据空间自相关特点关注不同集水区的碳排放“同化”作用。     

1990－2018年黄河流域<河南段>土地利用格局时空演变

研究长时间序列的土地利用时空演变规律,对科学推进黄河流域生态保护和社会经济高质量发展具有重要意义。该研究基于1990、2000、2010和2018年土地利用遥感数据,以具有中游和下游双重属性的黄河流域（河南段）为研究对象,利用土地利用变化指数、弦图（Chord Diagram）可视化模型及重心迁移模型,探讨了近30年黄河流域（河南段）土地覆被变化的流量、流向、多样性程度及政策启示。结果表明：1）粮食保障用地（约55%）和生产生活用地（约10%）主要分布在平原地带,生态保育用地（约35%）主要集中在海拔较高的山地。2）1990－2018年间旱地的流出和流入行为均体现出显著的主导性,水田、水域和草地以流出行为为主导,城镇用地、农村居民点和其他建设用地以流入行为为主导。3）中心城市的土地利用变化在整个时期内具有明显的区域带动效应。4）粮食保障用地和生态保育用地的重心均向西迁移且面积呈减少趋势,说明下游平原地带的优质耕地减少且生态系统服务功能在逐步减弱;生产生活用地面积逐年增加,城镇用地重心向东迁移表明下游各城镇的社会经济发展逐渐活跃,农村居民点和其他建设用地重心向西迁移表明中游的人口规模逐渐增大。     

Environmental impact of quarries on natural resources in Lebanon

Years of unregulated mining activity have left hundreds of abandoned quarries across Lebanon. Satellite images show that the number of quarries and areas they cover increased, from 784 quarries covering 2897 ha in 1989, to 1278 quarries covering 5267 ha in 2005. This paper presents a comprehensive approach to assess the impact of quarrying activities on scarce Eastern Mediterranean natural resources. The assessment is based on the computation of spatial indicators such as rainfall, slope gradient, vegetation cover, soil erosion risk, and rock infiltration, using GIS to appraise critical impacts on the Lebanese ecosystem. Compared with the 1989 baseline, the area consumed by quarries in 2005 increased more than three times over former arable lands, one third for forest lands and doubled for pasture lands. Quarries additionally destroyed 676, 137, and 737 ha of productive lands, respectively. The comparison of quarry distribution with the land capability map revealed that quarries are found mainly on productive soils, consuming 1314 ha in 1989 and 2192 ha in 2005 of prime lands. A total of 87 per cent of studied quarries represent serious hazards to groundwater quality. In general, a total of 272 quarries have high impact, 657 quarries have moderate impact, and 349 quarries have low impact on natural ecosystems. Analyzed data revealed that around 62 per cent of the quarries are located in a highly unsuitable environment. This paper presents recent findings from the Eastern Mediterranean for territorial suitability assessment of quarries to be considered in the frame of natural resources and coastal ecosystems management. Copyright © 2010 John Wiley & Sons, Ltd.     

晋西北地区土地退化特征及危害研究

土地退化是当前世界重要的环境问题,它严重地制约着社会经济的可持续发展。根据野外调查和前人的研究成果,探讨了晋西北地区土地退化的表现特点,成因和危害,并提出了土地退化的防治对策。     

Mapping Extent and Change in Surface Mines Within the United States for 2001 to 2006

A complete, spatially explicit dataset illustrating the 21st century mining footprint for the conterminous United States does not exist. To address this need, we developed a semi‐automated procedure to map the country's mining footprint (30‐m pixel) and establish a baseline to monitor changes in mine extent over time. The process uses mine seed points derived from the U.S. Energy Information Administration (EIA), U.S. Geological Survey (USGS) Mineral Resources Data System (MRDS), and USGS National Land Cover Dataset (NLCD) and recodes patches of barren land that meet a “distance to seed” requirement and a patch area requirement before mapping a pixel as mining. Seed points derived from EIA coal points, an edited MRDS point file, and 1992 NLCD mine points were used in three separate efforts using different distance and patch area parameters for each. The three products were then merged to create a 2001 map of moderate‐to‐large mines in the United States, which was subsequently manually edited to reduce omission and commission errors. This process was replicated using NLCD 2006 barren pixels as a base layer to create a 2006 mine map and a 2001–2006 mine change map focusing on areas with surface mine expansion. In 2001, 8,324 km² of surface mines were mapped. The footprint increased to 9,181 km² in 2006, representing a 10·3% increase over 5 years. These methods exhibit merit as a timely approach to generate wall‐to‐wall, spatially explicit maps representing the recent extent of a wide range of surface mining activities across the country. Copyright © 2015 John Wiley & Sons, Ltd.     

Land use/cover change and landscape fragmentation analysis in the Bindura District,Zimbabwe

Rapid land use/cover change and landscape fragmentation is occurring in many countries in central and southern Africa, as a result of colonial imbalances in land distribution, demographic pressure, agricultural expansion, government policies and environmental factors such as drought. This study analysed the dynamics of land use/cover and land degradation as revealed in landscape fragmentation in the Bindura District of Zimbabwe based on Landsat data for 1973 and 2000. A hybrid supervised/unsupervised classification approach coupled with GIS analyses was employed to generate land use/cover maps from which various class level landscape metrics were calculated using FRAGSTATS®, in order to analyse landscape fragmentation. The results show that agriculture, mixed rangeland, settlements, bareland and water increased, while woodland areas decreased. Consequently, the landscape became more highly fragmented as indicated by an increase in the patch number and a decrease in the mean patch size (MPS) of the woodland and mixed rangeland classes. This suggests that anthropogenic activities driven by agricultural expansion were the main causes of landscape fragmentation, leading to landscape degradation in the study area. Copyright © 2006 John Wiley & Sons, Ltd.     

大庆市土地退化时空变化及驱动力分析

以不同时段遥感影像为主要数据源,在GIS软件的支持下,提取了大庆市沙化土地和盐碱地的面积.分析了大庆市土地退化的时空变化格局以及多年平均降水量、干燥度及≥10 ℃积温等自然控制因子对土地退化的影响.运用多元回归方法及主成分分析方法,分析了土地退化与各社会经济因子之间的相关程度及影响土地退化的主导因子,并建立了土地退化驱动因子的诊断模型.研究结果表明,大庆市退化土地面积持续增加,区域变化也比较明显;退化土地年变化率在降水量400 mm,干燥度为1.14,≥10 ℃积温为2 780 ℃处变化最为显著;在社会经济因子中耕地面积数量、原油产量、人E1数量是导致土地退化的主导因素.     

Social Memory and the Resilience of Communities Affected by Land Degradation

Based on evidence collected in 22 village communities from nine study sites situated in Spain, Italy, Greece, Morocco and China, this study analyses the complex interlinkages between social memory, community resilience and land degradation. Social memory is seen as an important explanation regarding the ability of a local community to manage and cope with land degradation. Emphasis is placed on the importance of three components of social memory—rites, traditions and social learning processes—for shaping community resilience in coping with land degradation processes. The study argues that although there are subtle differences between the 22 village communities, the loss of social memory and learning pathways associated with managing land degradation is emerging as a critical factor constraining stakeholders from effectively responding to land degradation issues. Copyright © 2016 John Wiley & Sons, Ltd.     

青藏高原冻融荒漠化退化区分布及影响因素

[目的]青藏高原由于其高海拔、气温低、冻融侵蚀强烈的特点,是冻融荒漠化的主要发生区。探究青藏高原冻融退化区分布及其原因,对该区水土保持工作和生态环境保护具有重要参考意义。[方法]选择植被覆盖度、冻融循环次数、土壤温度日较差、土壤含水量、年降水量和坡度作为冻融侵蚀因子,对2000—2019年青藏高原冻融侵蚀敏感性进行了评价,结合研究期内青藏高原荒漠化趋势,构建了一种判定冻融荒漠化退化区域的方法。[结果]2000—2019年青藏高原冻融侵蚀区总面积为1.531×10⁶ km²,中度及以上敏感性区域面积为9.131×10⁵ km²,占青藏高原总面积的35.92%。青藏高原冻融荒漠化退化区域面积约为1.113×10⁵ km²,主要分布于高原西南部,退化程度以中度退化为主,面积占比为44.35%。[结论]气温上升、湿润指数下降和净太阳辐射增强是青藏高原冻融荒漠化发生的主要自然驱动因素,高原南部部分地区由于气候条件的差异,三者发挥了相反的作用。     

Quantification and Remediation of Soil Chemical Degradation in Tropical Australia,China and Thailand

Soil and land degradation in the tropics can be identified and described in terms of physical, chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences. Acharacteristic of these ecosystems is their capacity to recycle nutrients through soil organic matter (SOM).Following disturbance through changed land management, SOM is rapidly mineralized and there is a cor-responding decline in fertility and the variable charge component of the cation exchange capacity. As theseecosystems are strongly dependent on SOM for their functionality, changed land use can have irreversible im-pacts on the productivity of these systems. The paper focuses on quantifying chemical degradation throughprinting. Using values taken from the fingerprint of an undisturbed soil, an index of chemical degradationimprove poor quality soils in their natural condition are discussed, such as the addition of natural clays andsilicated materials. Results are present to show the effect of each of the aforementioned strategies on surfacecharge characteristics and associated increases in plant productivity.