Recreational trails, human activity, and nest predation in lowland riparian areas

In areas of human settlement, greenways and open-space land are often intended to serve recreational purposes as well as provide wildlife habitat, but the compatibility of these goals is uncertain. We examined the effect of recreational trails on the risk of nest predation and nest predator activity at four lowland riparian sites along the Front Range of Colorado. At one site on each of two streams, we placed a transect of artificial nests near a recreational trail and another transect on the opposite side of the stream. We also placed another transect of nests at a second site on each stream that was not associated with a recreational trail. In 1995, nests were baited with quail eggs; in 1996 a clay egg was also added to nests to aid us in nest predator identification. Artificial nests are not perfect surrogates for natural nests, but are useful in generating hypotheses about causes of nest failure and for detecting changes in predator assemblages.Overall, predation rates were high (94%). There were significant differences in vulnerability to predation on the different transect types, with a tendency for predation rates to increase with distance from trails. There was a significant effect of time with a greater risk of predation in 1996. In 1996, 83% of the clay eggs that were recovered showed signs of predation. House Wrens destroyed 11% of the clay eggs; impressions from Black-billed Magpies, Blue Jays, and Common Grackles were found on 69%; mice preyed on 25%; and squirrels on 12% of the eggs. Birds attacked more nests near trails than away from trails, whereas mammals appeared to avoid nests near trails to some extent. These results support the contention that recreational trails and human activity may affect nesting success for some species, and suggest that patterns of nest predation reflect the unique, and sometimes, counter-intuitive responses of individual predator species. Rather than relying on simplistic assumptions about the compatibility of recreation and wildlife, it is important to consider how individual species respond to the habitat alteration and human activity associated with trails when deciding where trails should be located and in developing overall conservation strategies in human-dominated areas.     

Developing and comparing optimal and empirical land-use models for the development of an urbanized watershed forest in Taiwan

The objective of this study is to demonstrate the utility of optimal spatial models for modeling specific spatial patterns to facilitate rational land-use planning of a watershed in northern Taiwan. Optimization was implemented using simulated annealing in a spatial pattern optimization model (OLPSIM), and developments predicted by the drivers of past land-use changes were modeled with the CLUE-s model. The landscapes simulated by the models were then input to a precipitation-runoff model (the Hydrologic Engineering Center's Hydrologic Modeling System; HEC-HMS) to assess the impact of land-use patterns on runoff in the watershed and sub-watershed scales. The results suggest that the three strategies produced very different landscapes under medium intensity scenarios. Specifically, maximizing the size of forest patches caused deforestation of small forest patches, resulting in a large, complex-shaped, dispersed forest; minimizing forest patch shapes resulted in the dissection of large, complex-shaped forests into smaller, simpler-shaped fragments; and land development based on past trends resulted in the aggregation of urbanized land-use in gentler terrains. The results of hydrological simulations suggest that the three land-use strategies differ less in their total hydrological outputs, but more in their distribution of hydrological outputs across different sub-watersheds. Investigating more spatially explicit hydrologic impacts of urbanization at the sub-basin scale may provide additional information that would help decision-makers evaluate proposed land-use policies more thoroughly.     

由单一走向多样：平原农业区生物多样性 保护的规划途径——以辽宁省黑山县为例

平原农业区的生产和土地利用方式严重影响区域的生物多样性,利用融合多学科的景观空间规划构建有效的评价方法和格局优化模式以实现多样化的生境保护和恢复,提升生物多样性具有重要的作用。以辽宁省黑山县为例,首先梳理了平原农业区对于生物多样性威胁的机制和研究的框架;其次识别平原农业区的特殊生境类型,使用景观格局指数和In VEST模型的生境质量评价构建多尺度生境质量评价机制;同时使用基于图论和电路理论的LinkageMapper软件,识别和分级空间中的重要生态源地、潜在廊道及廊道上的关键夹点区域。结果显示,农业景观中空间异质性和连接性影响生物多样性;研究区有主要生境23类,整体生境质量较差,农田面积较大是造成该问题的主要原因;识别出核心斑块33个,重要廊道34条,通过与卫星图比照,廊道位置与线性生境重合;关键夹点区域位于靠近农村居民点的自然生境上,故营造人类干扰与生态平衡农村居住区是空间规划的重点;同时根据以上研究提出了多尺度的空间规划途径,为平原农业区生境优化和生物多样性保护提供了一定的理论参考。     

Effects of urbanization on Neotropical wasp and bee assemblages in a Brazilian metropolis

The rapid growth of cities in many parts of the world has stimulated an increasing number of ecological studies of urban environments. Here, 12 study sites in the city of Belo Horizonte (MG), southeastern Brazil, were compared to analyze the effects of habitat changes related to urbanization on the species richness and abundance of native wasps and bees. Two spatial scales were considered: large portions of the urban landscape (entire sites) and small areas within these sites (public squares). Overall, the abundance of advanced eusocial bees (i.e. stingless bees), which were the dominant species, was directly affected by the loss of vegetation cover and the increase of buildings associated with urbanization. The magnitude of this effect varied according to the nesting habits of each species. The loss of vegetation cover associated with urbanization also had a negative effect on the abundance and species richness of advanced eusocial wasps. Generalist species of bees and wasps, such as Trigona spinipes and Polybia occidentalis, were very abundant and not sensitive to the habitat changes related to urbanization. Advanced eusocial bees also responded to small-scale habitat changes (size and vegetation cover of public squares). No relation was found between the solitary and the primitive eusocial wasps and bees and the habitat changes considered here. Conservation strategies in urban environments need to consider different spatial scales in order to maintain or enhance the local diversity of wasps and bees.     

基于Maxent模型的深圳湾鸟类热点生境 判别及修复研究

鸟类热点生境判别对于掌握鸟类空间分布格局、 识别保护空缺及指引生境修复策略具有科学价值。采用最大 熵模型确定深圳湾2000与2020年的鸟类热点生境,分析鸟 类生境的变化及其与景观格局演变的关系。结果表明：1)各 环境因子对不同生态类群的鸟类影响程度各不相同,除鸣禽 以外水源距离对其他类群鸟类的影响较大,其次为高程和 年降水量;2)2020年深圳湾的鸟类热点生境占总研究区的 3%(22km2),呈现从自然保护区向城市内陆逐渐减少的趋 势,存在2km2的保护空缺;3)20年间深圳湾鸟类的热点生 境减少了7%,热点生境下降的地区主要集中在深圳湾沿海滩 涂、香港山贝河与屯门河流域中,且猛禽与游禽的生境退化最 为严重;4)鸟类热点生境面积随斑块的数量、密度、形状与用 地类型等景观指数的增加而降低,景观破碎化和景观连通性降 低是导致鸟类生境退化的主要原因。研究为深圳湾鸟类多样性 保护及生境修复提供了参考,对粤港澳大湾区协同生态保护与 城市建设的关系具有重要意义。     

基于 MSPA-InVEST 模型的北京中心城区绿色空间生境网络优化

全球生物多样性下降严峻的背景下,优化生境网络对城市生物多样性保护具有关键作用,是当前城市绿色空间研究的重点内容。MSPA-InVEST模型对中心城区尺度绿色空间的生境网络优化具有优势性与创新性,以北京中心城区为研究区域,使用MSPA-InVEST模型遴选生境源地,并以此为基础识别生境廊道与生境节点。结果表明:研究区域大尺度生境斑块连通性欠缺,生境破碎化且质量呈两极化趋势;通过识别生境源地205个(32个核心生境源地)、生境廊道463.2 km(88.5 km关键生境廊道)、生境节点527个(49个重要生境节点),构建研究区域生境优化网络。在新时期生态建设背景下,研究结果能够准确指导未来北京市中心城区绿色空间建设,为生物多样性的保护与恢复提供重要支撑。     

Factors affecting changes in landscape diversity in rural areas of the Fagus crenata forest region of central Japan

We compared landscape diversity in a primary forest site and a coppice forest site in rural area of the Fagus crenata forest region of central Japan. We focused on the factors affecting landscape diversity, with special reference to land ownership, and the relationship between changes in landscape diversity and the spatial distribution of landscape elements. We were able to identify two patterns that led to increased landscape diversity in the study sites. In the first, which was most apparent in the primary forest site, increased diversity resulted primarily from an increase in the number of landscape elements. In the other, which was seen in the coppice forest site, increased diversity resulted from a decrease in the difference between the numbers of grid squares dominated by each landscape element while the number of landscape elements remained unchanged. Land ownership also had different implications for the increase of landscape diversity. The changes in the Contagion Index, which decreased in private land and increased in the national forest, showed that private land contains many small patches while the landscape of the national forest consists of a few large, contiguous patches. Thus, an evaluation of changes in landscape structure requires measuring a variety of indexes in addition to the diversity.     

Modeling spatially explicit population dynamics of Pterostichus melanarius I11. (Coleoptera: Carabidae) in response to changes in the composition and configuration of agricultural landscapes

The intensification of agricultural practices has induced the local, national and regional extinction of many species and also affected ecosystem services provided by biodiversity such as biological control of agricultural pests. We model the population dynamics of Pterostichus melanarius (Coleoptera: Carabidae), a carabid beetle often used as indicator species of habitat changes, by a joint model that combined a matrix model of population dynamics including local dispersal with an explicit model of the patchy landscape of the polders of the Bay of Mont St. Michel (Brittany, France). We used this model to evaluate the effects of landscape composition and configuration on the spatial population dynamics of this carabid beetle, and also investigated the consequences that different management strategies of the structure and composition of an agricultural landscape can have on its abundance and spatial distribution. The results of this study highlight that semi-habitats (field edges, dykes, hedgerows) usually considered as shelters for wintering play a key role as well for summer recruitment. We find that there is an optimal cluster size of patches for population viability that is induced by the seasonal movement of P. melanarius. However, the effect of increasing the amount of semi-natural habitats patches on the viability of this population critically depend on the spatial arrangement, connectivity and spatial alternation of the network of semi-natural habitats, a feature that should be considered in the conservation and management actions in the landscape context.     

基于生态位需求的高密度城区鸟类微生境选择研究—以上海市浦东新区世纪大道地区为例

选择上海市浦东新区世纪大道沿线地区作为样地,基于鸟类群落微生境调查,研究鸟类的生态位需求和实际的微生境选择,重点分析鸟类对高密度城区特殊微生境—建筑物/构筑物的选择偏好。结果表明:1)鸟类群落的巢居空间和食性空间生态位需求以及实际微生境主要位于乔木层和地被层;2)立体硬质界面具备成为城市野生鸟类生境的潜力,可作为现有城市生物生境系统的有益补充;3)针对部分城市野生鸟类利用建筑物孔洞筑巢的习性,建议可在建筑立面、雕塑和街道家具的设计中有意识地预留孔洞,为鸟类提供巢居空间。     

Factors influencing species diversity of ferns and fern allies in fragmented forest patches in the Kyoto city area

We investigated the relationship between species diversity of pteridophytes and the environmental factors of 39 fragmented forest patches in the Kyoto city area. There was a significant correlation between the number of species and the micro-landform diversity, artificial habitat diversity, and logarithm of the area of the forest patch. When we performed a multiple regression analysis to identify the best-fit model so as to optimize the amount of variation in species diversity explained by using stepwise selection, three species diversity indices (species richness or Shannon’s diversity index, logarithm of inverse Simpson index) had significant positive partial correlations with the logarithm of area of the forest patch, and negative correlations with the logarithm of isolation distance from mountain forest. Therefore, we conclude that pteridophyte species diversity depends on patch size and isolation distance from mountain forests. Comparison of the woody plant species–area curve with the pteridophyte species–area curve showed that the rate of increase of species number (inclination) with area was the same, but the Y-intercept of the pteridophyte species–area curve was lower than that of the woody plant curve. Therefore, the minimum conservation area required for ferns and fern allies is greater than that for woody plant species.     

Relating surface fire spread to landscape structure: An application of FARSITE in a managed forest landscape

Recent studies suggest that manipulation of landscape patterns is the most preferred method to reduce susceptibility of landscape to fire spread. We evaluated the effects of landscape spatial pattern and spatial heterogeneity of fuel loading on surface fire spread using the FARSITE model in Chequamegon National Forest landscape, Wisconsin. Five forest management scenarios were developed to generate different landscape spatial patterns with unique fuel loading distribution. For each management scenario, 16 fires were simulated. We found that altered landscape spatial pattern and spatial heterogeneity of fuel loading interactively influenced fire spread. Moreover, we revealed that numerous, irregular-shaped, and different types of patches reduced fire spread. Among tested indices of landscape spatial pattern, patchy density, mean patch shape, patch shape standard deviation, area weighted mean shape index (AWMSI) and Shannon's diversity index were meaningful for predicting fire spread. However, the effect of landscape spatial pattern on fire spread decreased as fuel loading became more spatially heterogeneous. We also found that the effect of landscape spatial pattern on fire spread became insignificant when AWMSI was less than 4.33. Our results suggested that a forest management plan would need to consider the number, shape, size and type of forest patches for regulating fire spread.     

The pattern of landscape patches and invasion of naturalized plants in developed areas of urban Seoul

Fragmented developed areas usually support source-sink patches for invasive organisms in urban landscapes. Invasive plants that have a different origin than the spreading source have an important role in artificial landscape restoration in degraded areas. However, many alien plant species have invaded the original habitat or ecosystem of native plants; sequentially their fast growing populations colonize neighboring ecosystems easily. Biological contamination sometimes occurs, unbalancing biodiversity in the natural landscape system. Therefore, long-term monitoring for dynamic communities after restoration in urban areas is indispensable for establishing a strategy for sustainable urban management. Under this principle we have examined the spreading of representative naturalized plant species according to recent land use changes. In this study, we have selected two representative invasive plants, Robinia pseudoacacia and Eupatorium rugosum. Their distribution pattern and patch characteristics of population were identified by the data of Seoul Biotope Map and a field survey. As a result of GIS-aided analysis of landscape patches, these two species often occurred in the same place. Concentration patterns of population distribution were found in forest edges disturbed by development of roads and human settlement. Especially, Eupatorium rugosum had extended to inner forest patches although the individuals were scattered. Distribution patterns of those species were partly related to landscape indices such as patch size and shape of the forest edge.     

基于InVEST模型和最小成本路径的城市绿色空间生境网络构建方法研究——以南京为例

提出以城市绿色空间为载体,选取不同生境类型、对城市化适应能力不同的物种为目标物种,结合物种观测数据和InVEST模型生境质量评估模块进行生境源地的识别及成本面信息的提取,应用最小成本路径综合模拟出城市绿色空间生境网络的方法。以南京为例,选取了9种鸟类作为目标物种,分析了其现状城市绿色空间网络结构。结果表明,迁移能力和城市化适应能力对物种分布的范围和生境类型的广泛程度影响较大。现状网络对城市化适应能力强或迁移能力强的物种较友好,对城市化适应能力差且迁移能力弱的物种有严重不良影响。对于综合的网络,中部的核心区多但被建设区割裂,北部的核心区少而分散,南部的核心区少但联系紧密,三部分的主要连通性结构为滁河、溧水河、秦淮河、秦淮新河和较连续的山林地或水库坑塘。此外,在半自然生境斑块内也生成了许多分散路径,部分联系紧密的斑块形成了组团结构。最后,根据以上结果提出了相应建议。     

厦门市绿地生态网络构建及优化策略

科学构建城市绿地生态网络,对区域生态安全、城市可持续发展及生物多样性保护具有重要意义。基于AHP法和GIS技术,定量分析厦门市自然生态本底,选取重要生态斑块和廊道,采用最小费用路径法模拟潜在廊道,综合构建城市绿地生态网络,并提出绿地生态网络优化策略。结果表明:1)AHP法可整合区域生态、经济、人文和社会等资源,全面客观评价现状生态斑块和廊道的重要程度;最小费用路径法可根据生境分布特征科学模拟连通各斑块之间的潜在廊道;2)厦门市西北部的生态基底适宜性、生态源地及廊道重要性、斑块之间有效连通性均高于东北部及中部平原区;岛内斑块面积小且分散,南北部存在断层现象,应适度增加踏脚石和连通廊道;3)结合城市生态发展需求,提出构建"一片、一环、三带、多廊道、多节点"的城市绿地生态网络。研究结果可为厦门市绿地系统规划提供科学依据。     

北京市中心城土地利用变化及其对 生境的影响(1992—2016)

随着城市化进程的发展,北京市中心城建设用地不断扩张,大量城市边缘区绿色空间被侵占,对城市生态环境造成极大影响。以北京市中心城1992和2016年的遥感数据作为基础数据,对其用地转换以及空间分布变化进行分析,运用In VEST模型评估土地利用变化对中心城生境的影响,获取北京中心城生境质量和生境退化的空间分布格局。研究表明:1992—2016年北京市中心城绿色空间用地绝大多数转变为建设用地,除草地面积增加外,其他绿色空间用地均有所减少;中心城高度生境和中度生境面积均缩小,一般生境面积显著增加,到2016年轻度退化生境占总面积的80.5%。在"留白增绿"的政策背景下,生境评价的结果为北京中心城绿色空间规划及城市森林建设提供了重要的参考依据。     

International greenways: a Red River Valley case study

Building and preserving a network of greenways can be an intricate activity requiring interdisciplinary collaboration. Greenway segments often require local input and participation. In addition, greenways are not necessarily generic open spaces, but can be managed structurally to fulfill specific spatial and temporal requirements. This paper describes local activities in the Fargo (North Dakota)-Moorhead (Minnesota) metropolitan area related to preserving and embellishing the greenway focused around the Red River Valley of the North. This greenway is part of a larger Western Hemisphere greenway, composed of riparian corridors operating as wildlife habitat migration flyways and as resident wildlife habitat. Local activities include demonstration gardens, comprehensive corridor planning, habitat analysis, and revegetation studies. From 1985 to 1990, four spatial treatment investigations were completed, one spatial planning study was prepared, and five demonstration gardens were built. The spatial treatment investigations revealed that the wildlife occupying the greenway could be divided into four habitat-use dimensions, suggesting four important habitat associations for the greenway. The study also revealed three distinct vegetation zones for re-establishing herbaceous vegetation in non-wooded planting conditions. In addition, one experiment indicated that replanting the disturbed woodland corridor was not influenced by seedling size and that Fraxinus pennsylvanica seedlings were highly successful at surviving in a gap opening within the forest corridor. In the last experiment, a seeding application rate study indicated that seeding rates three times higher than recommended rates resulted in improved vegetation cover of non-wooded herbaceous vegetation planting sites. The spatial planning study illustrated landscape patterns for the greenway composed of a continuous tree canopy corridor, augmented by herbaceous vegetation patches, food plots, and snags. To build and manage the greenway, this investigation reaffirms the importance of multi-disciplinary collaboration, local participation, and the potential individualistic structure of a greenway. The study suggests that both broad landscape planning visions and detailed site endeavors are necessary to understand and manage the greenway successfully.     

Fragmentation of a Landscape: incorporating landscape metrics into satellite analyses of land-cover change

The relationship between trajectories of forest-cover change and the biophysical and social characteristics of the landscape in the mountains of Western Honduras is addressed. Metrics of land-cover change were used to infer patterns of land-use change, using Landsat TM imagery from 1987, 1991 and 1996. With 15-20% of the land cover changing across each two-date period, the study landscape was very dynamic. Areas of reforestation were significantly larger than areas of deforestation, across all dates. Patch size was a good indicator of economic activity. Stable patches of forest and agriculture were fewer and larger, compared to forest regrowth and clearing. Small patches of swidden agriculture were found close to roads, at lower elevations and on more gradual slopes between 1987 and 1991. Between 1991 and 1996, expansion of export coffee production resulted in forest clearings on steeper slopes and at higher elevations. Results highlight the importance of landscape metrics in monitoring land-cover change over time.     

基于电路理论的多尺度城市热环境网络 构建及格局优化：以成都市中心城区为例

高密度、高强度的城市建设和扩张导致城市热岛效应不断增强,研究城市热环境网络格局以优化规划布局是改善城市热环境的有效方法。将形态学空间格局分析与电路理论相结合,立足多尺度,以成都市中心城区及其核心区为研究对象,选取连通性强的冷岛、热岛源地,根据景观格局特征与地表覆盖构建阻力面,运用Linkage Mapper识别廊道、冷岛障碍点和热岛夹点,并进行分级和评价,构建研究区热环境网络,提出多尺度下的格局优化建议。结果表明：1)中心城区尺度识别出23处冷岛源地、34条关键廊道、48处障碍点,廊道呈“串珠状”环绕研究区边缘分布,连通性和稳定性较弱;2)中心城区核心区尺度识别出34处热岛源地、81条关键廊道、98处夹点,廊道呈网状分布且普遍连通性较高,夹点是未来阻断热岛廊道连通的关键区域;3)研究区形成“两环多分支五组团多点”结构的城市热环境网络格局。研究结果可为成都市及其他城市的热环境改善提供科学参考,丰富电路理论在热环境领域中的应用。