斯里兰卡亚洲象栖息地生境质量时空变化及分异特征

斯里兰卡亚洲象栖息地是全球重要的亚洲象保护区,象群分布密度约为其他地区的10倍,但由于生境破碎与丧失以及人象冲突等原因导致亚洲象数量急剧下降。对斯里兰卡亚洲象栖息地的生境质量监测与评估能够为亚洲象及其栖息地的保护政策制定与规划提供理论依据,并在全球物种多样性保护中具有重要意义。为评估斯里兰卡亚洲象栖息地的生境质量,综合考虑亚洲象栖息地需求以及影响亚洲象栖息地的关键要素,应用InVEST-HQ模型来估算生境质量指数,同时分析亚洲象栖息地生境质量在海拔梯度及植被覆盖梯度上的分布状况;随后引入空间自相关分析方法在像元尺度上探讨亚洲象栖息地生境质量的空间分布模式与时间演化过程,进而分析栖息地内不同保护区和气候分区的生境质量所存在的空间分异特征。研究结果表明：在空间分布上,斯里兰卡亚洲象栖息地生境质量具有高度聚集性,空间异常值不显著。生境质量高值区主要集中在中低海拔、植被覆盖情况较好、保护区范围密集的区域;生境质量低值区集中于耕地面积大、海拔偏高的区域。在梯度分布上,斯里兰卡亚洲象栖息地生境质量对海拔和植被覆盖度均具有显著线性相关关系,且在较低海拔和较高植被覆盖度梯度上存在聚集现象。在区域尺度上,斯里兰卡亚洲象栖息地生境质量存在显著的地域差异性。栖息地内自然保护区的生境质量明显高于非自然保护区,其中严格自然保护区的生境质量相对较高;热带雨林气候带的生境质量高值聚类大于其余气候分区,而热带疏林草原气候带与热带季风气候带生境质量受到季节性降水的影响较大,高值像元占比偏少。在时间尺度上,斯里兰卡亚洲象栖息地的生境质量总体呈现先降低后趋于平缓的态势。1995年—2010年,生境质量高值聚类占比明显减少,低值聚类占比缓慢上升;2010年—2020年生境质量低值占比有小幅度下降,高值聚类逐渐增加,生境质量逐渐稳定并呈缓慢上升的趋势。     

基于HSI模型的吉林省东部地区生境质量动态评价

生境质量评价对生物多样性保护具有重要意义,能够为生态环境的恢复和保护、区域可持续发展政策的制定提供科学依据。以吉林省东部地区为研究区,基于2000年和2015年2期Landsat TM/OLI影像和数字高程模型(digital elevation model,DEM)数据,选取水源状况、干扰因子、遮蔽条件及食物来源作为评价因子,采用层次分析法确定权重,建立了生境质量评价模型,对吉林省东部地区进行生境质量动态评价,并从评价因子、土地覆被变化、社会经济及气候变化等方面分析变化原因。结果表明,吉林省东部地区2000年生境质量最好和较好的区域分别占研究区总面积的37. 69%和46. 88%,2015年生境质量最好和较好的区域分别占研究区总面积的41. 20%和44. 66%; 2000—2015年间生境质量变好的区域为9 414. 19 km2,变差的区域为5 627. 5 km2;土地覆被变化是导致生境质量变化的主要原因之一,吉林省大力发展生态旅游、退耕还林是生境质量变好的主要驱动力,气候条件适宜为吉林省东部地区生态环境保持长期稳定提供了有力保障。     

新疆地区鸟类和哺乳动物丰富度与环境因子的空间格局与关系

干旱区生态系统极易受到气候及土地利用变化的影响,其生物多样性格局及其形成机制是重要的生态学问题。基于新疆地区鸟类及哺乳动物物种多样性数据,结合气候、地形和长时间序列的植被遥感参数产品FAPAR数据等,主要在不同的土地利用类型及海拔带上采用单因子相关分析方法探讨了物种丰富度格局的形成机制。总体来说,不同生境类型中,植被遥感参数因子(DHI、NDVI等)与两种类群物种丰富度分布的相关性强于与气候因子(温度、降水)的相关性。具体而言,植被遥感参数因子中,基于FAPAR的生境指数因子与丰富度的相关性大于基于植被指数的因子(DHI_cumNDVI_cumEVI_cum);气候因子中,在草地生境或者较低的海拔上,年均降水因子对于丰富度分布的解释力强于年均温度因子。这表明在新疆地区,影响鸟类与哺乳类动物物种丰富度分布的主导理论是生境异质性假说与环境稳定性假说,其解释力在多种生境内均强于生产力与环境热量。     

重庆金佛山黑叶猴潜在生境及廊道分析

黑叶猴是国家一级保护动物,由于人类活动导致其生境破碎化加剧,威胁种群的生存安全。本文以黑叶猴在重庆的主要分布区金佛山为例,考虑地形、植被、人为活动和饮水因素等,选取与黑叶猴生境密切相关的7个环境影响因子,对黑叶猴生境适宜性进行了分析,并利用最小累积阻力(MCR)模型构建了潜在生境之间的生态廊道。结果表明,黑叶猴最适宜生境面积为178.07 km²,仅占研究区总面积的12.15%,主要分布在金佛山中部和东北部地区的沟谷地带,潜在生境斑块呈条带状,破碎化状态明显,具有海拔高、坡度陡、临近水源、植被覆盖度高、远离人为活动干扰等特点;构建的生态廊道共有56条,廊道最小宽度为303.9 m,廊道总长度为147.82 km,总面积为43.89 km²。本文的研究成果对黑叶猴种群和生境的保护具有重要指导意义。     

高黎贡山羚牛生境适宜性评价及廊道建设

以高黎贡山羚牛为研究对象,选取了植被类型、植被覆盖度、海拔、坡度、水源、土地覆被、主要道路、居民点8个影响因子,基于GIS技术,构建阻力面,从而探测多因子影响作用下高黎贡山羚牛适宜生境。结果表明：区域内羚牛的适宜生境面积整体占比较少,适宜区域主要分布在研究区的中西部及西南地区,在北部区域也有零散分布。羚牛的迁徙受到人类活动的干扰及道路阻隔的影响,其生境遭到一定程度的破坏。结合现有羚牛栖息地分布及最小阻力模型,建立区域内羚牛的生态廊道,结果显示：廊道主要分布于高黎贡山保护区南段、马边瓦底中段、子巴、俄恰沙迪、马士打亚窟、其期北段、四克洛娃俎及木当一带。     

基于GIS的贝叶斯统计推理技术在印度野牛生境概率评价中的应用

目前,ＧＩＳ技术已被广泛应用在野生动物生境研究中。但是,作为空间数据分析和处理工具,ＧＩＳ缺乏进行启发式推理的能力。因此,与擅长于此的贝叶斯统计推理技术相结合则是解决这一问题的重要途径。以西双版纳纳板河流域生物圈保护区为试验区,综合应用ＧＩＳ技术和多元统计技术建立印度野牛生境的两个逻辑斯蒂多元回归模型：趋势表面模型和环境模型,第一个模型的自变量是位置坐标,第二个模型的自变量是一组环境因子,然后应用贝叶斯统计合并这两个模型产生贝叶斯综合模型。结果表明,贝叶斯综合模型优于环境模型,可应用于野生动物生境概率评价。     

基于GIS的贝叶斯统计推理技术在印度野牛生境概率评价中的 …

目前,ＧＩＳ技术已被广泛应用在野生动物生境研究中。但是,作为空间数据分析和处理工具,ＧＩＳ缺乏进行启发式推理的能力。因此,与擅长于此的贝叶斯统计推理技术相结合则是解决这一问题的重要途径。以西双版纳纳板河流域生物保护区为试验区,综合应用ＧＩＳ技术和多元统计技术建立和印度野牛生境的两个逻辑斯蒂多元回归模型：趋势表面模型和环境模型,第一个模型的自变量是位置坐标,第二个模型的自变量是一组环境因子,然后应用     

北移亚洲象群夜间位置监测方法

本文主要对西双版纳国家级自然保护区原生活栖息的亚洲象群一路北上进行了夜间位置监测方案的设计及实践研究。首先,明确了方案的监测需求,包括夜间象群识别、实时动态位置更新、迁移路线绘制、路线及安全研判等;其次,介绍了方案的软硬件选型,主要以无人机结合红外相机为主;然后,讨论了方案设计,包括悬停高度、飞行设计、监测点衔接、识别、测量及交接等操作;最后,通过实践及结果分析得出,采用无人机结合红外相机的夜间位置监测方案,能有效实时识别亚洲象群,及时更新位置,绘制路线,提前预判象群行进路线,为象群迁徙提供有效的保护措施。     

基于3S技术的野生动物生境评价与保护研究——以高黎贡山羚牛为例

在3S技术和数理统计分析技术支持下,应用羚牛行为生态学研究成果,在研究羚牛生境分布与空间格局的基础上,通过空间分析,开展高黎贡山北段羚牛生境适宜性评价与保护研究。研究结果表明:适宜羚牛生存的生境面积有限,并有逐年减少的趋势,为有效保护高黎贡山羚牛,有必要加强羚牛现有生境保护,尤其是最适宜生境的保护;消除羚牛生境阻隔因素,增强生境连通性。     

基于InVEST模型的四川盆地生境质量时空演变分析

高质量生境对于维护生态系统平衡、促进人类社会和经济发展具有重要作用。本文通过研究四川盆地生境质量,更好地揭示人类活动对盆地生态系统的影响,为研究区生态系统的修复和发展提供一定的科学依据。结果表明:四川盆地2000—2020年的生境质量状况整体水平不高,但呈微弱上升趋势;生境质量空间分布上异质性表现明显,呈现研究区边缘生境质量状况较好、中间盆地底部生境质量整体较差的空间分布特征。生境质量与土地利用程度在空间上呈负相关,且相关程度缓慢减弱。研究结果确定了四川盆地生境质量相对较差的区域,对维护四川盆地生物多样性以及日后的发展规划具有一定的参考价值。     

Topographic and spectral data resolve land cover misclassification to distinguish and monitor wetlands in western Uganda

Wetlands provide vital wildlife habitat and ecosystem services, but changes in human land use has made them one of the world’s most threatened ecosystems. Although wetlands are generally protected by law, growing human populations increasingly drain and clear them to provide agricultural land, especially in tropical Africa. Managing and conserving wetlands requires accurately monitoring their spatial and temporal extent, often using remote sensing, but distinguishing wetlands from other land covers can be difficult. Here, we report on a method to separate wetlands dominated by papyrus (Cyperus papyrus L.) from spectrally similar grasslands dominated by elephant grass (Pennisetum purpureum Schumach.). We tested whether topographic, spectral, and temperature data improved land cover classification within and around Kibale National Park, a priority conservation area in densely populated western Uganda. Slope and reflectance in the mid-IR range best separated the combined papyrus/elephant grass pixels (average accuracy: 86%). Using a time series of satellite images, we quantified changes in six land covers across the landscape from 1984 to 2008 (papyrus, elephant grass, forest, mixed agriculture/bare soil/short grass, mixed tea/shrub, and water). We found stark differences in how land cover changed inside versus outside the park, with particularly sharp changes next to the park boundary. Inside the park, changes in land cover varied with location and management history: elephant grass areas decreased by 52% through forest regeneration but there was no net difference in papyrus areas. Outside the park, elephant grass and papyrus areas decreased by 61% and 39%, mostly converted to agriculture. Our method and findings are particularly relevant in light of social, biotic, and abiotic changes in western Uganda, as interactions between climate change, infectious disease, and changing human population demographics and distribution are predicted to intensify existing agricultural pressure on natural areas.     

Understanding the spatial distribution of elephant (Loxodonta africana) poaching incidences in the mid-Zambezi Valley,Zimbabwe using Geographic Information Systems and remote sensing

The objective of this study was to understand the factors that explain the spatial distribution of elephant poaching activities in the areas of the mid-Zambezi Valley, Zimbabwe using geographic information system (GIS) and remotely sensed data integrated with spatial logistic regression. The results showed that significant (α = 0.05) elephant poaching hot spots are located closer to wildlife protected areas. Results further demonstrated that resource availability (water and forage) are the main factors explaining elephant poaching activities in the mid-Zambezi Valley. For example, the majority of poaching activities were found to occur in areas with high vegetation fractional cover (high forage) and close to waterholes. The results also showed that poaching incidences were more prevalent during the dry season. The findings of this study highlight the significance of integrating GIS, remotely sensed data and spatial logistic regression tools for understanding and monitoring elephant poaching activities. This information is critical if poaching activities are to be minimized and it is also important for planning, monitoring and mitigation of poaching activities in similar protected areas across the sub-Saharan Africa.     

Elephants move faster in small fragments of low productivity in Amboseli ecosystems: Kenya

Understanding factors affecting the behaviour and movement patterns of the African elephant is important for wildlife conservation, especially in increasingly human-dominated savanna landscapes. Currently, knowledge on how landscape fragmentation and vegetation productivity affect elephant speed of movement remains poorly understood. In this study, we tested whether landscape fragmentation and vegetation productivity explains elephant speed of movement in the Amboseli ecosystem in Kenya. We used GPS collar data from five elephants to quantify elephant speed of movement for three seasons (wet, dry and transitional). We then used multiple regression to model the relationship between speed of movement and landscape fragmentation, as well as vegetation productivity for each season. Results of this study demonstrate that landscape fragmentation and vegetation productivity predicted elephant speed of movement poorly (R² < 0.4) when used as solitary covariates. However, a combination of the covariates significantly (p < 0.05) explained variance in elephant speed of movement with improved R² values of 0.69, 0.45, 0.47 for wet, transition and dry seasons, respectively.     

Vegetation analysis and study of its dynamics in Chandaka Wildlife Sanctuary (Orissa) using aerospace remote sensing

Changes brought in habitat conditions due to increasing human influences on natural areas have posed serious threat to wildlife. Remote Sensing has probably omerged as one of the most viable techniques to assess and monitor habitat conditions. Comparative analysis of maps of two-time period can provide authentic data with respect to changes brought in the habitat conditions. Chandaka Wildlife Sanctuary, covering an area of 213.71 sq. km in Orissa is one of the natural reserves of elephants which has undergone serious changes brought in through anthropogenic activities of urban areas of Cuttack and Bhubaneshwar lying within the proximity of the sanctuary. The natural reserve, an ideal habitat for elephants, was connected to neighbouring extensive forest belts. These connections have been either degraded or deforested over the years. The present study analyses the types of habitat available in the sanctuary using remote sensing data (aerial and satellite). Vegetation-type maps of 1975 have been prepared from B/W aerial photographs of 1:25,000 scale. For assessing the current vegetation types, maps have been prepared from Indian Remote Sensing Satellite (LISS II) false colour composite on 1:50,000 scale. Comparative evaluation of the maps indicates changes in the vegetation pattern, increase in mining and agriculture areas within the sanctuary. Stratified field sampling of vegetation types provide structural characteristics of the vegetation. Bamboo has been found to extend in the valleys and side slopes of the sanctuary area during past 15 years. An analysis on response of vegetation in all major vegetation types mapped have been made in the context of the invasion of Eupatorium odoratum. Finally, bamboo biomass has been assessed through stratified random sampling as it constitutes a major elephant food source.     

3维安保地理信息系统的设计与实现

传统的地理信息系统已经无法满足现代安保工作的需求,3维安保地理信息系统作用日益凸显。说明了系统建设目标、体系结构、技术路线,详述了系统建设,包括数据设计、功能设计与开发和关键技术,实现了亚运3维安保地理信息系统研发。满足了警务安保业务需求,在亚运安保中得以实际应用,为同类系统的研发提供有益借鉴。     

Identifying transit corridors for elephant using a long time-series

The role of corridors in mitigating the effects of landscape fragmentation on biodiversity is controversial. Recent studies have highlighted the need for new approaches in corridor design using long-term datasets. We present a method to identify transit corridors for elephant at a population scale over a large area and an extended period of time using long-term aerial surveys. We investigated environmental and anthropogenic factors directly and indirectly related to the wet versus dry season distribution of elephant and its transit corridors. Four environmental variables predicted the presence of elephant at the landscape scale in both seasons: distance from permanent water, protected areas and settlements and vegetation structure. Path analysis revealed that altitude and monthly average NDVI, and distance from temporary water had a significant indirect effect on elephant distribution at local scale in dry and wet seasons respectively. Five transit corridors connecting Tarangire National Park and the northern as well as south-eastern wet season dispersal areas were identified and matched the wildlife migration routes described in the 1960s. The corridors are stable over the decades, providing landscape connectivity for elephant. Our approach yielded insights how advanced spatial analysis can be integrated with biological data available from long-term datasets to identify actual transit corridors and predictors of species distribution.     

Corridor analysis in Rajaji-Corbett elephant reserve — A Remote sensing and GIS approach

This paper deals with corridor analysis in Rajaji-Corbett Elephant Reserve in the Shivaliks of Uttaranchal state. Efforts were made to detect changes in the state of forest covervis- à -vis the status of corridors during the three periods i.e. 1967. 1986 and 1998 using remote sensing and GIS. TheERDAS Imagine digital image processing andArcView GIS software packages were used for this purpose. Temporal satellite imagery and ground observations in the Rajaji-Corbett Elephant Reserve revealed forest loss, degradation and disturbances in the corridor areas, hindering elephant movement and restricting them to forests islands. Motichur-Chilla corridor, despite being a highly favoured habitat for the elephants was found to be highly threatened followed by Kotdwar and Ramnagar corridors. Construction of wide bridges across Kunao-Chilla Canal, recreation of corridors through reforestation, reduction of all kinds of pressures in the corridor areas and providing higher protection to corridors are recommended.     

Towards new applications of underwater photogrammetry for investigating coral reef morphology and habitat complexity in the Myeik Archipelago,Myanmar

Photogrammetry represents a non-destructive, cost-effective tool for coral reef monitoring, able to integrate traditional remote sensing techniques and support researchers’ work. However, its application to submerged habitats is still in early stage. We present new ways to employ Structure from Motion techniques to infer properties of reef habitats. In particular, we propose the use of Digital Surface Models and Digital Terrain Models for assessing coral colonies extension and height and discriminating between seabed and coral cover. Such information can be coupled with digital rugosity estimates to improve habitat characterization. DTM, DSM and orthophotos were derived and used to compute a series of metrics like coral morphologies, reef topography, coral cover and structural complexity. We show the potentialities offered by underwater photogrammetry and derived products to provide useful basic information for marine habitat mapping, opening the possibility to extend these methods for large-scale assessment and monitoring of coral reefs.     

Using information layers for mapping grassland habitat distribution at local to regional scales

The Natura 2000 network of protected sites is one of the means to enable biodiversity conservation in Europe. EU member states have to undertake surveillance of habitats and species of community interest protected under the Habitat Directive. Remote sensing techniques have been applied successfully to monitor biodiversity aspects according to Natura 2000, but many challenges remain in assessing dynamics and habitat changes outside protected sites. Grasslands are among the most threatened habitats in Europe. In this paper we tested the integration of expert knowledge into different standard classification approaches to map grassland habitats in Schleswig Holstein, Germany. Knowledge about habitat features is represented as raster information layers, and used in subsequent grassland classifications. Overall classification accuracies were highest for the maximum likelihood and support vector machine approaches using RapidEye time series, but results improved for specific grassland classes when information layers were included in the classification process.