拉萨市城关区近50年城市扩展过程对自然生境质量的综合影响

拉萨市城关区建设用地紧邻拉鲁湿地国家级自然保护区,导致城市发展与自然生境保护间的矛盾十分突出。全面揭示该地区城市扩展过程对自然生境质量的影响对于优化城市景观格局、保护生物多样性具有重要意义。为此,定量评价了该地区1968—2019年城市扩展过程对自然生境质量的综合影响。基于锁眼卫星遥感数据、Landsat系列遥感影像和Google Earth遥感数据获取了该地区土地利用/覆盖变化信息。结合空间叠加和模型模拟量化了城市扩展过程对自然生境质量的影响。结果表明,拉萨市城关区近50年城市扩展过程不断加快,城镇建设用地面积从9.78 km~2增加到67.67 km~2,增加了近6倍。城市扩展过程导致自然生境质量加速下降,近50年下降了12.69%。自然生境质量同时受到城市扩展过程的直接影响和间接影响。在各类自然生境中,林地和湿地的生境质量下降尤为明显,分别下降了96.59%和49.21%。其中,林地主要被城镇建设用地直接占用,湿地则主要受城市扩展过程的间接影响。因此,需要同时关注城市扩展过程对自然生境的直接占用和间接影响,采取有效措施协调城市建设与生物多样性保护,促进区域可持续发展。     

城市扩张导致京津冀区域生境质量下降

城镇化发展极大地改变了区域生境分布格局和功能,从而影响区域生态安全。因此,开展生境质量的评估,对于城市生态安全保障具有重要作用。基于In VEST生境质量模型,评估了京津冀区域2005—2015年生境质量时空变化格局。研究结论如下:1)2005—2015年,京津冀生境面积减少7134.2 km~2,占2005年生境面积的3.7%。耕地、草地和水域生境面积分别减少5081.0、1695.1、421.6 km~2,占对应类型生境面积的4.7%,4.9%和7.2%。2)京津冀生境质量从0.88降至0.83,下降幅度达5.69%。其中,耕地生境质量下降最为严重,其次为水域生境质量。3)生境质量下降区域主要沿北京-保定-石家庄-邢台-邯郸等经济发展迅速的区域分布,表现为城市扩张侵占原有生境。4)京津冀高生境质量斑块破碎度增加,低生境质量斑块集聚度增加。整体上看,京津冀区域生境斑块破碎度增加。     

Changes in light pollution in the Pan-Third Pole's protected areas from 1992 to 2021

Light pollution driven by human activities is undergoing unprecedented changes, which may profoundly impact biodiversity and habitat conservation. The Pan-Third Pole (PTP), one of the world's richest biodiversity regions, is experiencing rapid population growth and urbanization, along with continuously increasing light pollution. Protected areas (PAs) represent a cornerstone in safeguarding biodiversity and habitats. However, light pollution in the PTP's PAs also shows a growing trend. Using the harmonized global nighttime light (NTL) data, we studied the spatio-temporal variation in light pollution in the PTP's PAs from 1992 to 2021. The results showed that the light pollution area in the PTP's PAs increased by about 3-fold from 1992 to 2013 and about 1.2-fold from 2014 to 2021. The levels of increase varied across regions and altitudes. Southeast Asia and Centre Asia had the highest and lowest rates of increase, respectively. Higher-altitude areas had higher rates of increase, especially in areas above 3000 m. The increases in light pollution have a close relationship with urban expansion. In the PAs and their surrounding area, an increase of 1 km² in the urban area resulted in at least 9 km² of the PAs being affected by light pollution.     

区域城市扩张对森林景观破碎化的影响——以粤港澳大湾区为例

森林生境丧失与景观破碎化是引起生物多样性下降,生态系统功能降低的重要原因。量化森林景观破碎化的时空特征及其与城市扩张格局的关系是开展区域生态修复与功能提升的重要基础。本文以快速城市化的典型区域——粤港澳大湾区为研究对象,基于遥感解译的1980年、1990年、2000年、2010年和2018年土地覆盖/利用专题图,通过多尺度的景观格局分析和统计分析,定量解析森林景观破碎化的时空演变特征及其与城市扩张格局间的关系。研究结果显示：1）1980-2018年,大湾区林地覆盖面积缩减1,274 km²,林地转变为建设用地的面积占林地丧失总面积的比例从1980-1990年的11%增长至2010-2018年的42%,表明城市扩张已成为林地丧失的主导因素;2）森林景观破碎化程度加剧,表现为林地斑块密度提高,平均斑块面积减小,但破碎类型与程度具有地域差异;3）城市扩张幅度与空间格局显著影响林地破碎化,其中,城市扩张幅度对林地破碎化的影响更为重要。基于森林景观破碎化与城市扩张的现状,落实城市增长边界划定、关键斑块-廊道识别与生态网络构建等措施,有助于保护与连通重要生态空间,保障和提升生态功能。     

基于随机森林模型的国家重点保护陆生脊椎动物物种优先保护区的识别

准确可靠地识别国家重点保护陆生脊椎动物物种的优先保护区,是生物多样性保护的热点问题之一。采用随机森林(random forests)模型,基于12个环境变量,对中国263种国家重点保护陆生脊椎动物建模,并预测各个物种在背景点的适生概率,迭加计算得到国家重点保护陆生脊椎动物物种的生境适宜性指数。此外,基于对生境适宜性指数的空间自相关分析,识别和确定国家重点保护陆生脊椎动物物种优先保护区,并对优先保护区目前的被保护情况进行分析。结果表明,国家重点保护陆生脊椎动物物种的优先保护区的面积为103.16万km~2,约占我国国土面积的10.90%。优先保护区主要分布在我国的西部地区,包括西南地区的秦岭-大巴山山区、云南省与印度及缅甸的交界地区、武陵山山区、喜马拉雅山-横断山脉山区、阿尔泰山脉山区、天山山脉山区、昆仑山山脉山区;东北的大、小兴安岭、东北-华南沿海地区及长江中下游地区有少量分布。优先保护区中被保护的面积为50.40万km~2,占优先保护区总面积的48.86%,保护率偏低,未被充分保护。利用系统聚类分析,将未被保护的优先保护区划分成3种优先保护顺序,以期为相关部门的决策提供科学依据,更好地保护生物多样性。     

Odorous House Ants (Tapinoma sessile) as Back-Seat Drivers of Localized Ant Decline in Urban Habitats

Invasive species and habitat disturbance threaten biodiversity worldwide by modifying ecosystem performance and displacing native organisms. Similar homogenization impacts manifest locally when urbanization forces native species to relocate or reinvade perpetually altered habitat. This study investigated correlations between ant richness and abundance in response to urbanization and the nearby presence of invasive ant species, odorous house ants (Tapinoma sessile), within its native region. Surveying localized ant composition within natural, semi-natural, and urban habitat supported efforts to determine whether T. sessile appear to be primary (drivers) threats as instigators or secondary (passengers) threats as inheritors of indigenous ant decline. Sampling 180 sites, evenly split between all habitats with and without T. sessile present, yielded 45 total species. Although urbanization and T. sessile presence factors were significantly linked to ant decline, their interaction correlated to the greatest reduction of total ant richness (74%) and abundance (81%). Total richness appeared to decrease from 27 species to 18 when natural habitat is urbanized and from 18 species to 7 with T. sessile present in urban plots. Odorous house ant presence minimally influenced ant communities within natural and semi-natural habitat, highlighting the importance of habitat alteration and T. sessile presence interactions. Results suggest urbanization releases T. sessile from unknown constraints by decreasing ant richness and competition. Within urban environment, T. sessile are pre-adapted to quickly exploit new resources and grow to supercolony strength wherein T. sessile drive adjacent biodiversity loss. Odorous house ants act as passengers and drivers of ecological change throughout different phases of urban ‘invasion’. This progression through surviving habitat alteration, exploiting new resources, thriving, and further reducing interspecific competition supports a “back-seat driver” role and affects pest management strategies. As demonstrated by T. sessile, this article concludes native species can become back-seat drivers of biodiversity loss and potentially thrive as “metro-invasive” species.     

Islands,mainland, and terrestrial fragments: How isolation shapes plant diversity

The fragmentation of natural habitats is a major threat for biodiversity. However, the impact and spatial scale of natural isolation mechanisms leading to species loss, compared to anthropogenic fragmentation, are not clear, mainly due to differences between fragments and islands, such as matrix permeability. We studied a 500 km² Mediterranean region in France, including urban habitat fragments, continuous habitat, and continental‐shelf islands. On the basis of 295 floristic relevés, we built species–area relationships to compare isolation in fragments after urbanization, with continuous habitat and continental‐shelf islands. We assumed either no dispersal, infinite dispersal, or estimated intermediate levels of habitat reachability through graph theory. Isolation mechanisms occurred in fragments but with a lower strength than in near‐shore islands, and most importantly affected perennial plants. Annual plants were less affected, probably due to their smaller size and shorter life cycle. Isolation occurred at landscape level in fragments and at patch level in islands. The amount of reachable habitat (accounting for spatial configuration) explained local species richness in both systems, but the amount of habitat (no consideration of spatial configuration) was already a good predictor. These results suggest an important role of habitat amount around fragments in mitigating the isolation effects observed in near‐shore islands, and the importance of carefully considering different functional groups.     

Urban expansion and its consumption of high-quality farmland in Beijing,China

China faces the challenge of using limited farmland to feed more than 1.3 billion people. Accelerated urbanization has exacerbated this challenge by consuming a large quantity of high-quality farmland (HQF). It is therefore essential to assess the degree to which urban expansion has preferentially consumed HQF, and discern the mechanism behind this. We found urban areas in Beijing to expand at speeds of 48.97 km²/year, 21.89 km²/year, 62.30 km²/year and 20.32 km²/year during the periods 1986–1995, 1995–2000, 2000–2005 and 2005–2020, respectively. We developed an indicator of HQF consumption due to urban expansion, representing the ratio of HQF consumed to its proportion of overall farmland, and found its values were 2.21, 1.57, 1.99 and 1.10 for 1986–1995, 1995–2000, 2000–2005 and 2005–2020, respectively. Thus, although HQF has been overrepresented in the farmland consumed by Beijing's urbanization, this phenomenon has decreased over time. Centralized expansion has contributed greatly to consumption of HQF. Topography and distances to urban and water bodies determine the relative consumption of HQF in urbanization.     

关中平原城市群扩张对生态用地的多尺度影响

城市扩张与生态空间保护的矛盾是新型城镇化和国土空间规划过程中急需解决的问题之一。作为黄河流域生态保护与高质量发展的核心区域,关中平原城市群面临更加严峻的生态和资源胁迫。但相关研究主要对研究区整体的生态环境变化进行测度,少有研究分析城市群发展对生态用地的多尺度影响,且忽略了城市群中土地变化最剧烈,生态受胁迫最严重的城市边缘区。因此,基于土地利用数据,结合土地利用转移矩阵、景观指数、估算城市扩张间接影响的生态用地面积等方法,研究从城市群、重点城市和主要城市边缘区3个尺度分析1990-2018年城镇扩张对生态用地的直接和间接影响。结果表明：（1）关中平原城市群土地利用类型以半生态用地（耕地）为主,面积占比超过40%。而城市边缘区主要以半生态用地和建设用地为主。1990-2018年城市群建设用地面积比例由3.67%增长至5.93%,耕地面积共计减少3032.11 km²,自然生态用地的面积增加628.03 km²。受耕地占补、退耕还林等多重政策的影响,半生态用地和自然生态用地的变化呈现为"拉锯式"发展特征。（2）城市扩张对半生态用地的直接影响大于对自然生态用地的直接影响,各尺度土地利用转移变化大同小异,新增建设用地的主要来源均为耕地,其中城市边缘区的耕地受城镇扩张的挤占最为突出。（3）城市扩张对自然生态用地的间接影响大于直接影响,且不同城市建设用地对自然生态用地的间接影响因耕地补偿机制的不同而有所差异。因此,对关中平原城市群实施"一刀切"的耕地补偿政策实际上并不合理,应当因地制宜,考虑地区土地资源条件,适当调整发展和约束政策,更有利于城市群的可持续发展。     

生态保护区外斑块对景观连接度的影响评价

快速的城市化过程带来的生境斑块破碎化及损失会影响物种迁移、捕食等生态活动,对生物多样性构成威胁。然而,现有生态保护区可能无法覆盖其内生物的必要活动范围。生态保护区外的生境斑块对于维持生态过程也具有重要作用,因此识别生态保护区外的关键斑块并加以保护非常重要。以北京市延庆区为研究区,划分两种生境斑块,即核心生境斑块和潜在生境斑块,并基于图论构建生境网络。考虑地表覆盖类型、坡度、人类活动等因素构建生境阻力面。结合未来土地利用类型变化的模拟,研究城市化过程对区域生境网络和景观连接度的影响,选用CLUE-S模型模拟土地利用类型变化的格局。结合生境斑块特征和未来城市土地利用变化情况设计了3种未来生境变化情景。利用连接概率指数(PC)和网络连接度变化率(dI)评价不同生境变化情景下生态保护区外潜在生境斑块的景观连接度重要性,判断保护优先顺序,并分析景观格局变化对不同迁移能力物种的影响。结果表明：生态保护区外的全部潜在生境斑块对维持生境整体景观连接度有最大2.15%的影响,单个潜在生境斑块对维持景观连接度有最大0.28%的影响。此外,景观格局及其变化对不同迁移能力物种的影响差异显著,因此需针对保护物种和城市生境特征设计保护方案,研究区需要优先保护大中型斑块和位于关键位置的小型斑块。为了满足对生物多样性保护的需求,建议在区分生境斑块保护优先顺序时考虑生境斑块对景观连接度的贡献和城市化扩展过程的压力。研究为城市生物多样性保护和生境管理提供了方法参考。     

1988-2013年重庆市主城九区生态用地空间结构及其生态系统服务价值变化

在当前快速城市化的背景下,理解和把握城市生态系统服务功能退化原因及规律的最有效手段是对其生态用地结构及其生态系统服务价值进行准确的评估。采用RS、GIS技术以及生态系统服务价值评估等方法,对重庆市主城九区1988、1996、2004、2013年4个时段遥感影像进行解译及比较分析,结果表明：1988-2013年间,重庆市主城九区城市化水平经历了加速阶段、减速阶段及饱和阶段,城市化水平的提高对城市建设用地增长的影响显著;重庆市主城九区生态用地主要为城市提供了食物生产、提供原材料、废物处理、土壤形成与保护、气候调节、气体调节、生物多样性以及水源涵养等生态系统服务,在结构变化上呈现出“二减三增”的结构变化特点;25年间重庆市主城九区共减少生态系统服务价值260.60×10⁶元,整体处于下降趋势,其中农地的生态系统服务价值损失最大,共减少24.50%;在空间分布上,随着城市建设用地向“南-北-西”方向扩展,生态系统服务价值以中梁山与铜锣山之间的区域减少最为严重,整个研究区生态系统服务价值下降的主要原因来自于农地的大量减少以及城市建设用地扩张所带来的生态负影响。研究结果表明在重庆市主城九区生态用地空间格局与生态系统服务变化之间存在密切相关性,在城市化率达到饱和阶段后应严格控制建设用地增长,促进建设用地集约节约利用,加大农地的保护力度以及对林地、水体、草地的维护,维持整个区域的生态平衡。研究可为科学合理布局和保护城市生态用地提供信息资料和决策参考。     

粤港澳大湾区生态系统格局变化与模拟

快速城市化是导致粤港澳大湾区生态系统时空格局变化的主要驱动力之一,模拟生态系统变化趋势对于优化区域土地利用格局、防控城市化的生态风险具有重要意义。以2000、2005、2010、2015、2018年5期土地利用数据,分析该区域生态系统格局演变,并运用CA-Markov模型模拟2025年的生态系统格局。研究结果表明:(1)2018年大湾区的森林、农田和城镇为主要生态系统类型,分别占区域总面积的53.99%、22.67%和14.51%。(2)2000—2018年农田、森林、湿地面积分别下降了1983、740、278 km~2,城镇和草地面积分别上升了2896、103 km~2,城镇面积增长的主要途径是对周围农田、林地和湿地的侵占,草地面积增长是因为管理经营不善导致部分林地退化为草地。(3)大湾区的景观多样性和均匀度下降,景观正在向小斑块趋势发展,空间连通性下降,破碎度增加。(4)模拟2025年的生态系统格局发现,与2018年相比,城镇面积增长了609 km~2,农田和森林分别减少了309 km~2和316 km~2。基于大湾区生态系统格局变化与模拟发现,快速城市化区域中,落实耕地保护红线和生态保护红线制度、保护重要生态空间完整性,对于降低城市化的生态风险具有重要作用。     

西辽河上游生境质量时空演变特征与影响机制

西辽河上游是我国辽河流域的重要水源地,其生境质量的好坏关系到下游流域生态安全和人类福祉。然而针对西辽河上游生境质量及其影响机制的研究还有待深入。基于ArcGIS软件、InVEST模型,定量分析了西辽河上游1980—2018年土地利用和生境质量的时空演变特征;并进一步探究了西辽河上游生境质量变化的主要驱动因子。结果表明：(1)1980—2018年,西辽河上游草地面积较1980年下降了21.93%,其中大部分转化为林地(7719.09 km²)、耕地(6014.90 km²)和裸地等(3025.71 km²)等,各斑块的空间分布异质性增加;尽管研究期内,林地面积较基期大幅度提升了48.67%,但全区域平均生境质量指数由0.74下降到0.72。(2)该地区无论在区域本底环境和区域社会经济发展水平上,均对于西辽河上游的生境质量改善产生了积极作用,年均气温(0.218)、降水(0.229)、地区生产总值(0.850)和受教育程度(0.132)与生境质量指数呈现较为明显的正相关关系;然而,本地区城镇化速率(-1.137)、景观分离度...     

1990年来中国城镇建设用地占用耕地的效率和驱动机理时空分析

定量揭示城镇建设用地与耕地的时空变化关系和相互作用机理,是如何实现城镇建设用地需求与耕地资源保护二者间动态平衡的关键问题之一。基于1990—2015年全国城镇建设用地及耕地的空间数据,在对比分析中国31个省份近25年来的城镇建设用地及耕地时空格局变化的基础上,定量求算因城镇建设用地扩张导致耕地减少的速率,并引入数据包络分析法和地理探测器,实现自1990年以来中国城镇建设用地占用耕地的驱动效用机理。结果表明:1)在时间维度上,1990—2015年间,中国城镇建设用地增长2.6×10⁴ km²,增速107%,而扩张速率以2.4%/5 a逐渐降低。1990—2000年耕地呈增加趋势(增加2.96×10⁴ km²),2000年后呈减少趋势,总体减少速率为0.29%/5 a。全国新增城镇建设用地占用2.12×10⁴ km²耕地,占城镇新增总量的72.5%;2)在空间分布上,全国城镇建设用地扩张面积由东向西逐渐减小,但2010后的西部区域扩张速度呈上升趋势。耕地面积在西北和东北地区有所增加,东部和中部呈减少趋势,城镇建设用地占用耕地比例由东部向西部逐渐减弱,但中东部耕地被建设用地占用形式仍然严重;3)在城镇建设用地占用耕地的效用上,1990—2015年,全国城镇建设用地占用耕地的产出效益呈现降低趋势,其中产出效益超过0.8的省份主要分布在沿海地区,西北地区产出效益普遍较低。分析结果显示,经济发展因素是新增城镇建设用地占用耕地的主要驱动因素,其次为空间位置因素和政策措施,自2010年后政策因素的驱动作用强度呈增加趋势。     

Regional Assessment of Urban Impacts on Landcover and Open Space Finds a Smart Urban Growth Policy Performs Little Better than Business as Usual

Assessment of landscape change is critical for attainment of regional sustainability goals. Urban growth assessments are needed because over half the global population now lives in cities, which impact biodiversity, ecosystem structure and ecological processes. Open space protection is needed to preserve these attributes, and provide the resources humans need. The San Francisco Bay Area, California, is challenged to accommodate a population increase of 3.07 million while maintaining the region’s ecosystems and biodiversity. Our analysis of 9275 km² in the Bay Area links historic trends for three measures: urban growth, protected open space, and landcover types over the last 70 years to future 2050 projections of urban growth and open space. Protected open space totaled 348 km² (3.7% of the area) in 1940, and expanded to 2221 km² (20.2%) currently. An additional 1038 km² of protected open space is targeted (35.1%). Urban area historically increased from 396.5 km² to 2239 km² (24.1% of the area). Urban growth during this time mostly occurred at the expense of agricultural landscapes (62.9%) rather than natural vegetation. Smart Growth development has been advanced as a preferred alternative in many planning circles, but we found that it conserved only marginally more open space than Business-as-usual when using an urban growth model to portray policies for future urban growth. Scenarios to 2050 suggest urban development on non-urban lands of 1091, 956, or 179 km², under Business-as-usual, Smart Growth and Infill policy growth scenarios, respectively. The Smart Growth policy converts 88% of natural lands and agriculture used by Business-as-usual, while Infill used only 40% of those lands. Given the historic rate of urban growth, 0.25%/year, and limited space available, the Infill scenario is recommended. While the data may differ, the use of an historic and future framework to track these three variables can be easily applied to other metropolitan areas.     

Natural,not urban,barriers define population structure for a coastal endemic butterfly

Habitat loss and fragmentation are the major causes of biodiversity loss, and, increasingly, habitat is fragmented by urbanization. Yet, the degree to which urbanization creates barriers to animal dispersal remains poorly understood. We used population genetic techniques to determine whether urbanization and/or natural landscape features are dispersal barriers to a butterfly, Atrytonopsis new species 1, throughout its range on coastal sand dunes that are increasingly threatened by development. Using AFLP markers that produced 89 polymorphic loci, we found significant population structure across the range of Atrytonopsis sp1. We found no indication that existing levels of urbanization were barriers to Atrytonopsis sp1 dispersal. Rather, two natural barriers, an ocean inlet and maritime forest, explained the genetic structure. Even in areas with long histories of urbanization, we found no significant isolation-by-distance relationship, and there was very low genetic differentiation between sampling locations. Consequently, conservation strategies for Atrytonopsis sp1, and potentially for other mobile insects that use open-structured habitats, should not focus explicitly on habitat corridors through urban areas, but rather should seek to preserve and restore as much habitat as possible across the butterfly’s range.     

Urban stress is associated with variation in microbial species composition—but not richness—in Manhattan

The biological diversity and composition of microorganisms influences both human health outcomes and ecological processes; therefore, understanding the factors that influence microbial biodiversity is key to creating healthy, functional landscapes in which to live. In general, biological diversity is predicted to be limited by habitat size, which for green areas is often reduced in cities, and by chronic disturbance (stress). These hypotheses have not previously been tested in microbial systems in direct comparison to macroorganisms. Here we analyzed bacterial, fungal and ant communities in small road medians (average area 0.0008 km²) and larger parks (average area 0.64 km²) across Manhattan (NYC). Bacterial species richness was not significantly different between medians and parks, but community composition was significantly distinct. In contrast, ant communities differed both in composition and richness with fewer ant species in medians than parks. Fungi showed no significant variation in composition or richness but had few shared taxa between habitats or sites. The diversity and composition of microbes appears less sensitive to habitat patchiness or urban stress than those of macroorganisms. Microbes and their associated ecosystem services and functions may be more resilient to the negative effects of urbanization than has been previously appreciated.     

东部发达区生态安全格局构建——以苏南地区为例

随着城市化进程的加快,东部发达区面临水土流失、生态廊道阻断、栖息地破碎化等生态问题。识别重要生态用地,构建生态安全格局,对区域生态保护和可持续发展具有重要意义。选取苏南地区为研究区,分别基于生物多样性保护价值、水资源安全和土壤保持3项指标进行生态用地识别,结合GIS技术进行生态用地评价,以高等级生态用地作为源地;利用最小累积阻力模型,识别缓冲区和生态廊道,构建区域生态安全格局。取得以下研究结果:(1)生态安全格局由源地、廊道和缓冲区共同构成。研究区内高等级(非常重要)生态用地面积比例为22.97%;将面积大于10 km~2的高等级生态用地提取为源地,生态源地的面积比例为19.17%。(2)基于最小累积阻力模型,确定了生态缓冲区和生态廊道,其中生态缓冲区占研究区总面积的30.52%,潜在生态廊道的主要景观构成为耕地、林地和水域,分别占廊道总面积的31.82%、19.06%和17.27%。(3)通过叠加城市建设用地与生态源地、生态缓冲区图层,识别城市建设用地与生态用地的冲突区域,总面积为603.84 km~2,占源地与缓冲区面积总和的4.38%,空间上主要集中在长江沿线和太湖周边。     

基于无人机遥感的三江源国家公园藏野驴种群数量及生境时空变化研究

藏野驴（Asinus kiang）是青藏高原特有物种,我国一级野生保护动物。三江源国家公园黄河源园区是藏野驴的主要栖息地之一,而生物多样性保护也是国家公园的重要职能,准确了解藏野驴的种群数量及栖息地变化无论是从野生动物保护还是从国家公园建设指导来看均具有重要意义。以三江源国家公园黄河源园区为研究区,利用无人机遥感技术开展藏野驴种群数量调查工作,在此基础上利用选择指数与因子分析揭示藏野驴的生境选择偏好,识别其适宜栖息地范围。并深入探讨近20年藏野驴适宜栖息地的时空变化特征,探讨驱动因素。结果表明：（1）无人机可以有效识别藏野驴个体,在调查样带内共发现藏野驴252头,经过推算2017年春季三江源国家公园黄河源园区内共有藏野驴20989头。（2）藏野驴倾向于选择距居民点1 km以外,距道路1-3 km范围内,距水源1 km以内,且植被覆盖度介于0.4-0.8之间的坡度小于5°的平坦区域做为栖息地。（3）2000-2018年间,三江源国家公园黄河源园区内的藏野驴适宜生境面积增加了330.76 km²,达到4747.10 km²,面积占比增加1.73%,达到了24.85%。这主要是气候变化与人类活动协同作用下导致的水体扩张与植被覆盖度增加驱动的。此外,虽然道路的扩张仅限制了小面积的适宜栖息地增加,但可能造成栖息地连通性下降等更为严重的后果。本研究证明了无人机遥感技术在青藏高原等开阔区域进行野生动物调查及栖息地研究的可行性与优势,相关技术方法与研究成果可为三江源国家公园生物多样性保护工作提供参考与支撑。     

长江经济带快速城镇化对耕地保护的影响

长江经济带建设作为我国三大发展战略之一,在快速推进城市化的同时,对耕地资源的影响是不容忽视的。土地快速城镇化对耕地的大量侵占是我国城市化面临的突出问题,而近些年长江流域及长江经济带的快速发展对耕地资源的影响尚缺乏全面系统的分析。基于中分遥感数据,将覆盖长江经济带与长江流域范围的156个地级市作为研究目标,从自然区位(上、中、下游)与城市规模(人口规模)相结合的角度分析了2000—2015年城镇化对耕地的影响,结果表明:(1) 2000—2015年,长江流域及长江经济带人工表面增加56.80%,耕地减少17.09%。其中,下游人工表面增加幅度最为明显,耕地减少也是最多的;(2)随着时间推移,长江流域及长江经济带城镇化对耕地的压力逐渐减弱,十五年间人工表面增长率从2733.75 km~2/a提高至2985.87 km~2/a,而耕地减少的速度从4439.94 km~2/a降低到3940.91 km~2/a,并且有大量旱田向水田转变;(3)位于不同流域且规模不同的城市,其人工表面的增加幅度以及对耕地的影响存在明显差异。例如,长江下游的中等城市人工表面15年间增加最多(增幅385.88%),同时耕地也损失最多;中游的大城市的人工表面增速最快,而上游则是巨大型城市,这种现象说明长江流域存在发展不协调的问题。长江流域及经济带未来城市优化布局不仅要充分考虑耕地保护问题,还要均衡不同规模城市的扩张速度,以及进一步提高开发用地的利用效率。