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1.
We review the current state of research on vegetation heterogeneity in the Monte Desert at scales varying from landscape to intra-patch. Different factors are related to vegetation heterogeneity at every scale. At a coarse scale (i.e. landscapes and communities) vegetation heterogeneity is commonly determined by abiotic factors, whereas biotic interactions usually influence fine scale (patch, intrapatch) heterogeneity. Communities are distributed at the landscape scale according to differences in precipitation, topography and soil attributes. On the other hand, there is evidence that the spatial pattern of plant patches within communities is determined by runon –runoff processes, although biotic influences such as grazing can induce changes in the spatial pattern of patches when plant cover is strongly reduced. In the same way, at patch and intrapatch scales, biotic interactions (i.e. plant –plant interactions, grazing) determine the size and the species composition of plant patches as well as the distribution of species inside plant patches. However, the mechanisms operating behind such biotic interactions at small scales are commonly related to plant-induced changes in the physical environment. We also found evidence of cross-scale interactions, feedbacks, and non-linear effects such as those induced by grazing disturbance. Our analysis showed some regional differences in patterns and processes related to vegetation heterogeneity along the Monte Desert which can be ascribed to climatic and taxonomic variation among areas. Although information about vegetation heterogeneity and its causes and consequences in the Monte Desert is abundant, some areas where knowledge is scarce are detailed. 相似文献
2.
The relationship between spatial scale and biodiversity patterns is a highly debated topic in ecology. We evaluated the partition of small mammal diversity at multiple spatial scales and analyzed protected areas in order to evaluate their role of protecting biodiversity at the regional scale. Diversity of small mammals in the Monte Desert was quantified at the regional biome scale (96,000 km2) (γ) and partitioned at three spatial scales: aridity range (α3,n = 6,16 000 km2), locality level (α2,n = 18,2-3 ha), and habitat patch (α1,n = 51,0.6 ha). We estimated their diversity using an additive approach with three indices (richness, Shannon-Weiner, Simpson). Diversity was higher than expected at the “between aridity range (β3)” scale, but lower at the “within-habitat scale (α1)”. Alpha was higher than beta diversity for most spatial scales; and at the regional scale protected areas preserved a higher biodiversity than unprotected ones. Our results are the first to partition the diversity of desert small mammals at multiple spatial scales and to support the hypotheses of an irregular scale dependence of alpha and beta diversity when increasing the spatial scales. They also highlight that a better understanding of biodiversity patterns is gained when several tools are integrated and combined at different spatial scales. 相似文献
3.
María C. Mateo Sánchez Samuel A. Cushman Santiago Saura 《International journal of geographical information science》2014,28(8):1531-1546
Animals select habitat resources at multiple spatial scales. Thus, explicit attention to scale dependency in species–habitat relationships is critical to understand the habitat suitability patterns as perceived by organisms in complex landscapes. Identification of the scales at which particular environmental variables influence habitat selection may be as important as the selection of variables themselves. In this study, we combined bivariate scaling and Maximum entropy (Maxent) modeling to investigate multiscale habitat selection of endangered brown bear (Ursus arctos) populations in northwest Spain. Bivariate scaling showed that the strength of apparent habitat relationships was highly sensitive to the scale at which predictor variables are evaluated. Maxent models on the optimal scale for each variable suggested that landscape composition together with human disturbances was dominant drivers of bear habitat selection, while habitat configuration and edge effects were substantially less influential. We found that explicitly optimizing the scale of habitat suitability models considerably improved single-scale modeling in terms of model performance and spatial prediction. We found that patterns of brown bear habitat suitability represent the cumulative influence of habitat selection across a broad range of scales, from local resources within habitat patches to the landscape composition at broader spatial scales. 相似文献
4.
The spatiotemporal landscape heterogeneity implies multiple biodiversity mechanisms across scales, and the cross-disciplinary studies between landscape ecology and biodiversity are becoming a new research field in China. This paper briefly reviews the development of the field by comparing papers published in international journals and Chinese journals;then it investigates the differences in the trends and focuses between international and Chinese studies. We also introduce several study areas that have emerged over the last 10 years in this field, including metacommunity assembly, landscape genetics, biodiversity and ecosystem service relationship, and landscape planning for biodiversity conservation. The major advances emerging in this field in China over the past 5 years can be classified into six subject areas: 1) effects of urban landscape and urbanization on biodiversity;2) altitudinal patterns of biodiversity in mountain landscapes;3) effects of topographic heterogeneity on plant community assembly and species coexistence;4) impacts of landscape patterns and processes on animal behaviors;5) forest fires and spatiotemporal patterns of vegetation responses;and 6) landscape ecology applications in natural conservation planning and design. In an attempt to promote cross-field studies between geography and ecology, this special issue collected 10 research articles, involving multiple landscape types and biological assemblages, in order to explore the interaction between landscape features and biodiversity. We anticipate that the future development of this active front will be primarily driven by the application of novel information techniques and the realistic demands of sustainability issues, in addition to answering scientific questions cross scales. 相似文献
5.
生物土壤结皮：荒漠昆虫食物链的重要构建者 总被引：4，自引：3，他引：1
干旱荒漠地区由于水分因子的限制,其植被分布以不连续的高等植物斑块与隐花植物及其结皮的斑块镶嵌为其主要特征,构成了独特的荒漠植被景观格局。作为荒漠生态系统的主要组成者,荒漠昆虫与生境的关系,特别是与高等植物之间的食物链关系已得到大量的文献报道。本文基于野外调查和实验室模拟观测,发现了尖尾东鳖甲(Anatolica mucronata)对藓类结皮有取食现象,哈蛃(Haslundichilis sp.)对地衣结皮有取食现象。证实了生物土壤结皮直接参与了荒漠昆虫食物链和食物网的构成,为深入了解生物土壤结皮在荒漠生态系统中的功能和地位提供了实验证据。 相似文献
6.
QIAN Yibing WU Zhaoning ZHANG Liyun SHI Qingdong JIANG Jin TANG Lisong 《地理学报(英文版)》2004,14(4):447-455
1IntroductionStudy on the interrelationship between vegetation patterns and their habitat heterogeneity is important to recover and rehabilitate the desert vegetation, stabilize the desert ecosystem and prevent desert expansion. Domestic and foreign researchers have carried out many studies on this topic (Archer etal., 2002; Bolling etal., 2000; Chen etal., 2003; Dasti etal., 1994; Gu etal., 2002, Li etal., 2001; Li etal., 2001; Liang etal., 2003), which have used and refined statistic tech… 相似文献
7.
We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species. 相似文献
8.
This paper reports a geomorphologic landscape investigation, vegetation survey and soil sampling at 14 sites across the Gurbantunggut Desert between 87o37'09'-88o24'04'E and 44o14'04'-45o41'52'N. The study encountered 8 species of low trees and shrubs, 5 of perennial herbs, 8 of annual plants and 48 of ephemeral and ephemeroid plants. These species of plants represent one-third of the species found in the Gurbantunggut Desert, and their communities make up a large proportion of desert vegetation with great landscape significance. In the investigation we found that the plant communities are accordingly succeeded with the spatial variation of macro-ecoenvironment. Using Principal Component Analysis (PCA) and Correlation Analysis (CA) we found that the micro-ecoenvironment heterogeneity of aeolian sandy soil's physical and chemical properties such as soil nutrient, soil moisture, soil salt, pH etc. only impacted the diversity of herb synusia (PIEherb) of the desert, with a negative correlation. Meanwhile, the impact of microhabitat on the plant community pattern with an antagonistic interaction made vegetation's eco-distribution in a temporary equilibrium. 相似文献
9.
本文运用景观生态学原理,借助ArcGIS技术,选择中国北方10个流域及其12个沙漠/沙地,并以西部的和田河和东部的西辽河为典型研究区,在流域与沙区、河道与沙丘两个尺度上,选取景观破碎度指数、景观多样性指数等指标,探讨中国北方干旱、半干旱区沙漠/沙地景观与廊道景观(河流)的空间镶嵌格局特征。结果表明：在流域与沙区尺度上,内流区较外流区沙区景观类型复杂,景观破碎度较小,外流区沙区景观结构较为相似;内流区沙区景观指数自西向东呈现出“景观破碎度递增、景观结构复杂性递减”的规律。在河道与沙丘尺度上,在缓冲带范围内,和田河较西辽河沙丘景观类型复杂,景观破碎度较小;景观指数随河道距离的变化呈现出“景观破碎度随距河道距离的加大而逐渐递减,丰富度指数随距河道距离的加大而呈阶梯状递增”的规律;从沙丘斑块类型景观指数上看,西辽河以固定、半固定的简单型沙丘为主,和田河以流动的综合型沙丘为主。主导的沙丘类型景观距离河道越远,面积比例越小,不同沙丘类型的水平景观破碎度随河道距离递减。 相似文献
10.
在野外考察的基础上,选择13个典型样地,研究了巴丹吉林沙漠南缘植被组成、群落特征和植被格局。结果表明：调查的样地中有荒漠植物31种,其中灌木12种,多年生草本11种,一二年生草本8种。种群密度3 000—14 000株·hm-2,优势种在群落中地位显著,群落稳定性较差;植被斑块面积小、最大斑块指数低。沙漠南缘年降水量虽然仅100 mm左右,但有霸王（Zygophyllum xanthoxylon）、红砂（Reaumuria soongarica）和沙蒿（Artemisia desertorum）等灌木和半灌木天然植物群落分布,有白刺（Nitraria tangutorum）和膜果麻黄（Ephedra przewalskii）灌丛沙堆,沙丘上生长着沙拐枣（Calligonum mongolicum）、沙鞭（Psammochloa villosa）等种群生存,且在沙漠延伸带流动沙丘上已成功建立了梭梭（Haloxylon ammodendron）人工固沙植被,表明在巴丹吉林沙漠南缘建立以乡土植物为主的固沙植被是可行的。在未来研究中,应在山水林田湖草沙生命共同体理念下加强从区域尺度上解析水、植被和沙的关系,系统了解生态系统的原真性、完整性和连通性及生态系统稳定性维持等问题,优化生态景观格局,确定生态保护目标和建设规模,同时要加强对乡土植物适应干旱风沙机制和扩繁保育技术研究,以便为区域生态建设和生态保护提供科技支撑。 相似文献
11.
The existing literature proposes that productivity is responsible for biodiversity gradients in terrestrial habitats at large extents. At smaller spatial scales, however, other explanatory variables diminish or weaken the effect of the productivity predictor. These ideas have not been tested directly using ant communities. We studied a small extent of the geographical gradient of ant species richness in the Central Persian Desert ecoregion, Iran. We evaluated support for productivity and a series of alternative models with additional variables to examine determinants of ant species richness. Our results supported nine models. The productivity model and the tolerance–productivity model received the highest support. A curvilinear relationship was evident between ant species richness and productivity. In contrast to earlier work, we found that the ant species richness increased with increasing latitude. Our results suggest that in this desert ecosystem, plant productivity is the most important variable that controls ant species richness. Productivity did not completely explain the spatial gradient in ant species richness. At small spatial scales, other variables that co-vary with productivity have significant roles. 相似文献
12.
The Okavango Delta in Botswana hosts abundant wildlife and a human population with diverse livelihoods. Representing a heterogeneous landscape nuanced by spatial and temporal variability, the region has recently seen an expansion of floodwaters with social impacts ranging from livelihood disruption to human displacement. This article reports on in-depth interviews conducted in 2012 regarding these transitions in Mababe, a community in the eastern Okavango Delta, to evaluate how dynamic environmental processes alter perceptions and livelihood responses. We focus on community members’ variable interactions with wildlife in spaces of human–wildlife overlap also experiencing change. While human–wildlife interactions can have negative effects, we find that perpetuating the common narrative of human–wildlife conflict overlooks how disruptions can usher in new relationships between people and animals. In order to move beyond the conflict narrative, we conclude that spatial and temporal context is essential to evaluate effects of dynamic, uneven, and sometimes unpredictable human–wildlife encounters. 相似文献
13.
This paper reports a geomorphologic landscape investigation, vegetation survey and soil sampling at 14 sites across the Gurbantunggut Desert between 87°37′09"-88°24′04"E and 44°14′04"-45°41′52′Nl. The study encountered 8 species of low trees and shrubs, 5 of perennial herbs, 8of annual plants and 48 of ephemeral and ephemeroid plants. These species of plants represent one-third of the species found in the Gurbantunggut Desert, and their communities make up a large proportion of desert vegetation with great landscape significance. In the investigation we found that the plant communities are accordingly succeeded with the spatial variation of macro-ecoenvironment.Using Principal Component Analysis (PCA) and Correlation Analysis (CA) we found that the micro-ecoenvironment heterogeneity of aeolian sandy soil′s physical and chemical properties such as soil nutrient, soil moisture, soil salt, pH etc. only impacted the diversity of herb synusia (PIEherb) of the desert, with a negative correlation. Meanwhile, the impact of microhabitat on the plant community pattern with an antagonistic interaction made vegetation′s eco-distribution in a temporary equilibrium. 相似文献
14.
A suitable spatial scale needs to be selected in geographical and landscape ecological research, and this requires great consideration as different scales have profound effect on derived landscape spatial patterns. Numerous studies have investigated the effects of different scales on landscape metrics using simulated patterns, but few have been conducted to compare different data sources with variable scale for regional- and landscape-scale assessments. Possibly this has occurred because researchers have been prone to use the best available source, a well-known standard, and easiest to use. This study was conducted to assess the impact of input data resolution on values of landscape pattern metrics in four landscapes at scales 1:10 000, 1:50 000 and 1:100 000. The aim was to determine the applicability of three data sources for thematic models in landscape pattern analyses in the Eastern Baltic region. We found that the utility of CORINE Land Cover data for comprehensive structural assessment in mosaic-type landscapes was very limited, as the level of cartographic generalization excluded many small and linear landscape structure elements with potentially high importance for landscape functioning, such as habitat continuity. We also found that actual area harvested using clearcuts was considerably higher than shown in CORINE data, due to clearcuts size being much smaller than the minimum mapping unit. In the light of this, we suggest using data with spatial resolution corresponding to a cartographic scale of at least 1:50 000, in cases when spatial patches have size up to 25 ha. 相似文献
15.
A. Nelson T. Oberthür S. Cook 《International journal of geographical information science》2013,27(2):145-174
All systems have causes and effects that can be appreciated at different spatial scales. Understanding and representing the complexity of multi‐scale patterns in maps and spatial models are key research objectives. We describe the use of three types of correlation analyses: (1) a standard Pearson correlation coefficient, (2) a ‘global’ multi‐scale correlation, and (3) local geographically weighted correlation. These methods were applied to topographic and vegetation indices in a small catchment in Honduras that is representative of the country's hillsides agro‐ecosystem which suffers from severe environmental degradation due to land‐use decisions that lead to deforestation, overgrazing, and unsustainable agricultural. If the geographical scale at which topography matters for land‐use allocation can be determined, then integration of knowledge systems can be focused. Our preliminary results show that: (1) single‐scale correlations do not adequately represent the relationship between NDVI and topographic indices; (2) peaks in the global multi‐scale correlations in agricultural areas coincided with the median farm size, but there was no evidence of any community or larger‐scale land‐use planning or optimization; and (3) local multi‐scale correlations varied considerably from the global results at all scales, and these variations have a strong spatial structure which may indicate local optimization of land use. 相似文献
16.
Rapid urbanization leads to losses in arable land; quantitatively analyzing the impact of urbanization on arable land is significant for arable land management. However, changes in arable land due to urbanization with scale and neighborhood effects remains poorly understood at the town scale. In this study, high-resolution historical land use data, landscape metric analysis and spatial regression were integrated to quantify the impacts of urbanization on arable land use change (abandonment and conversion) at spatial scales of 300 m–3300 m using a block size increment of 200 m and at the catchment scale in the town of Jinjing in subtropical central China. Arable land abandonment was the predominant type of arable land change and presented strong spatial autocorrelations at each spatial scale. Arable land was converted to tea fields because agricultural structure transformations were occurring around the urban cores, and the amount of arable land converted to residential land accounted for only a small proportion of the total arable land loss and had no spatial autocorrelation. The significance and robustness of the arable land changes impacted by urbanization had obvious scale effects and strong neighborhood effects in nearby regions. Compared with block scales, the catchment scale is an optimal scale for assessing the influence of urbanization and applying planning policy. Our results highlight the significance of incorporating spatial interactions in urbanization research, which can generate less biased estimations and consequently lead to proper policy implication and recommendations. In addition, multi-scale comparisons are helpful for better understanding the relationships between arable land changes and urbanization and provide further insights into the harmonious development of rural settlements and urban cores to preserve arable land. 相似文献
17.
Scientific interpretation of the relationships between agricultural landscape patterns and urbanization is important for ecological planning and management. Ordinary least squares (OLS) regression is the primary statistical method in previous studies. However, this global regression lacks the ability to uncover some local-specific relationships and spatial autocorrelation in model residuals. This study employed geographically weighted regression (GWR) to examine the spatially varying relationships between several urbanization indicators (urbanization intensity index, distance to urban centers and distance to road) and changes in metrics describing agricultural landscape patterns (total area, patch density, perimeter area ratio distribution and aggregation index) at two block scales (5 km and 10 km). Results denoted that GWR was more powerful than OLS in interpreting relationships between agricultural landscape patterns and urbanization, since GWR was characterized by higher adjust R2, lower Akaike Information Criterion values and reduced spatial autocorrelations in model residuals. Character and strength of the relationships identified by GWR varied spatially. In addition, GWR results were scale-dependent and scale effects were particularly significant in three aspects: kernel bandwidth of weight determination, block scale of pattern analysis, and window size of local variance analysis. Homogeneity and heterogeneity in the relationships between agricultural landscape patterns and urbanization were subject to the coupled influences of the three scale effects. We argue that the spatially varying relationships between agricultural landscape patterns and urbanization are not accidental but nearly universal. This study demonstrated that GWR has the potential to provide references for ecological planners and managers to address agricultural landscapes issues at all scales. 相似文献
18.
猫头刺群落对土壤养分空间异质性的响应 总被引：7，自引：6，他引：1
选择腾格里沙漠边缘内蒙古阿拉善左旗境内的猫头刺群落为研究对象,探讨了猫头刺群落植物属性和土壤属性随尺度变化\,空间异质性的变化以及植物属性对土壤属性空间异质性的响应。结果表明,尺度从800 m2增加到1 600 m2,土壤有机质和土壤全氮的空间异质性减小,全磷和有效磷的空间异质性增加,有效氮空间异质性不变,而群落内3种植物密度和叶量的空间异质性基本都趋于增加,说明全磷和有效磷是目前猫头刺群落存在的主要限制因素,尤其是多年生草本植物骆驼蓬。进一步分析表明,这种现象是由于荒漠地区的灌丛“沃岛效应”和植物耗用有效磷以增大吸水力的补偿机制所致。 相似文献
19.
入室盗窃多尺度地理因子分析 总被引：4，自引：0，他引：4
选取N市作为研究区域,以该市2013年全年的入室盗窃案件作为研究对象。将研究区域内入室盗窃与地理因子在不同空间尺度上进行关联性对比分析。首先,从环境犯罪学理论和现有犯罪地理特征研究两方面出发,分析现有研究中的尺度依赖性。每一套环境犯罪学理论均有其适用的空间尺度,在犯罪地理特征研究中会有相应的地理因子与之关联;其次,引入似不相关回归模型获取入室盗窃与地理因子在小区、街区、社区、街道以及区等多个空间尺度上的关联性。并用瓦尔德检验来测试各个关联系数之间差异的显著性。实验结果表明,随着尺度的变化,有些地理因子与入室盗窃的关联性并未变化,有些则发生了显著变化。这些变化可用不同尺度的犯罪地理学理论进行解释;最后,将多个尺度地理因子反演入室盗窃空间分布的结果进行综合,并将之与单一尺度的反演结果进行比较。结果证明,与单一尺度的地理因子反演犯罪空间分布的精度相比,利用多个尺度地理因子解释犯罪空间分布的精度更高。研究表明：在犯罪地理学研究中,环境犯罪学理论、地理因子分析以及犯罪空间分布反演均存在尺度依赖性。综合多个尺度的结果进行分析,不仅有利于准确认识犯罪的地理因子及其对应理论,对于犯罪反演精度也有所提高。 相似文献
20.
A resource selection function is one that yields values proportional to the probability of use of a resource unit. This quantity is influenced by the heterogeneity of landscape structures, which occurs over multiple spatial scales. To provide input into wildlife management strategies, we investigated the scale dependency and functional responses of Japanese macaques using multiple scale analysis. The multiple buffers with radii of 100, 500, 1000, 1500, 2000, and 2500 m were defined as the spatial scale. Crop damage was predicted at the within-home range scale, using the Random Forests algorithm with environmental variables linked to resource selection of Japanese macaques. Sixteen environmental variables were defined, covering aspects of landscape configuration, human disturbance, topography, and adopted countermeasures. Crop damage was most accurately predicted within a buffer zone of 1000 m, although radii exceeding 1000 m were also highly accurate. Although the importance of variables differed among spatial extents, the functional responses for each environmental variable were independent of spatial extent. These results suggest that the limiting factors of crop damage depend on spatial extent, while functional responses in resource selection remain constant across spatial extents. We also compared a multi-scale gradient map with a typical binary map to demonstrate the uncertainty in damage predictions at different spatial scales. Our results may aid wildlife management planning, for which differences in resource selection across different spatial scales are critically important. 相似文献