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1.
Kibale National Park, within the Albertine Rift, is known for its rich biodiversity. High human population density and agricultural conversion in the surrounding landscape have created enormous resource pressure on forest fragments outside the park. Kibale presents a complex protected forest landscape comprising intact forest inside the park, logged areas inside the park, a game corridor with degraded forest, and forest fragments in the landscape surrounding the park. To explore the effect of these different levels of forest management and protection over time, we assessed forest change over the previous three decades, using both discrete and continuous data analyses of satellite imagery. Park boundaries have remained fairly intact and forest cover has been maintained or increased inside the park, while there has been a high level of deforestation in the landscape surrounding the park. While absolute changes in land cover are important changes in vegetation productivity, within land cover classes are often more telling of longer term changes and future directions of change. The park has lower Normalized Difference Vegetation Index (NDVI) values than the forest fragments outside the park and the formerly logged area—probably due to forest regeneration and early succession stage. The corridor region has lower productivity, which is surprising given this is also a newer regrowth region and so should be similar to the logged and forest fragments. Overall, concern can be raised for the future trajectory of this park. Although forest cover has been maintained, forest health may be an issue, which for future management, climate change, biodiversity, and increased human pressure may signify troubling signs.  相似文献   

2.
Landscapes surrounding parks in most of the developing world, while still containing considerable biodiversity, also have rapidly growing human populations and associated agricultural development. Since the establishment of Kibale National Park first as a Crown Forest Reserve in 1932 and later as a park in 1993 in western Uganda, most access and resource extraction has been prohibited. The park has become nearly a complete island of forested land cover surrounded by intensive small-scale agriculture and some large-scale tea plantations, along with a network of wetland and forest patches. As the population grows outside the park and land becomes more scarce, remaining forests and wetlands are being used more intensively for material resources (e.g., fuelwood, building poles) and converted to other land uses (e.g., pasture, agriculture). This study uses both discrete and continuous data analyses of satellite imagery to examine these diminishing resource bases at the landscape level placing the results within the social context of conservation and parks. Findings reveal that the park boundaries have remained fairly intact whereas, the landscape surrounding the park has become increasingly fragmented. From a landscape perspective, while the park has indeed maintained its forest cover, it has become increasingly islandized with wetland and forest patches in the surrounding landscape becoming smaller in number and size. Those that have survived are now more isolated and even lower productivity than in 1984, which may be a precursor to their eventual loss in this landscape.  相似文献   

3.
We used an integrated modeling approach to simulate future land cover and predict the effects of future urban development and land cover on avian diversity in the Central Puget Sound region of Washington State, USA. We parameterized and applied a land cover change model (LCCM) that used output from a microsimulation model of urban development, UrbanSim, and biophysical site and landscape characteristics to simulate land cover 28 years into the future. We used 1991, 1995, and 1999 Landsat TM-derived land cover data and three different spatial partitions of our study area to develop six different estimations of the LCCM. We validated model simulations with 2002 land cover. We combined UrbanSim land use outputs and LCCM simulations to predict changes in avian species richness. Results indicate that landscape composition and configuration were important in explaining land cover change as well as avian species response to landscape change. Over the next 28 years, urban land cover was predicted to increase at the expense of agriculture and deciduous and mixed lowland forests. Land cover changes were predicted to reduce the total number of avian species, with losses primarily in native forest specialists and gains in common synanthropic species such as the American Crow (Corvus brachyrhynchos). The integrated modeling framework we present has potential applications in urban and natural resource planning and management and in assessing of the effects of policies on land development, land cover, and avian biodiversity.  相似文献   

4.
Little is known about urban forest planning, management and its benefits in emerging countries. The uneven distribution of tree canopy cover and parks in urban area is related to environmental justice, especially with disadvantaged socio-economic and marginated communities. However, the inequity of urban forest in many cities of emerging countries where often found irregular and unregulated land use patterns and social and socio-economic inequities, is hardly highlighted. This study explores the inequity of distribution of tree canopy cover and public park in Cali, Colombia. Utilizing the traditional socio-economic indices, the stratification, linear regression analysis is conducted to describe relationship between total tree canopy cover, tree canopy cover of various land use types, number of parks and park area per capita. The result demonstrates that lower income communities have lower tree canopy cover, fewer parks and smaller park area than higher income communities. This paper discusses importance of accounting for urban forests and ecosystem service in city planning efforts and better strategies of reducing inequity in emerging countries. Addressing the inequity of urban forest could be a better strategy to create resilient, sustainable, safe and livable cities in emerging countries.  相似文献   

5.
We analyzed forest clearing and regrowth over a 23-year time period for 21 forest concession and management units within the Maya Biosphere Reserve(MBR), Guatemala. The study area as a whole experienced a clearing rate of0.16%/year from 1974 through 1997. The overall clearing rate appears rather low when averaged over the entire study area over 23 years because most of the reserve was inaccessible. However, despite the granting of legal protection to the MBR in 1990, clearing rates continued to rise, with the highest rates occurring in the most recent time period in the analysis, 1995 to1997. Higher rates of clearing relative to regrowth occurred in newly established communities and in the Reserve's buffer zone, where the clearing of high forest was preferred for pasture development. Exploratory models were built and analyzed to examine the effects of various landscape variables on forest clearing. The different units in the analysis showed different relationships of forest clearing with variables such as forest cover type and distance to access(roads and river corridors). Where available, socio-economic household survey data helped to explain patterns and trends observed in the time series Landsat imagery. A strong relationship between forest clearing and distance to access was demonstrated. More clearing occurred further from roads during later time periods as farmers moved deeper into the forest to find land to clear. Communities inside the MBR that were less dependent on farming had forest clearing to regrowth ratios of one:one or less. These communities used fallow fields in greater proportions than communities in the Reserve's buffer zone. General trends in clearing by forest cover type suggest a preference for clearing high forest (bosque alto) types found on the higher elevation, better-drained soils, and fallow fields,and an avoidance of low-lying, seasonally flooded terrain(bajos). Satellite remote sensing observations of forest clearing and regrowth patterns can provide an objective source of information to complement socio-economic studies of the human driving forces in land cover and land use change. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

6.
在遥感和GIS技术的支持下,借助各种遥感影像,采用转移矩阵和景观斑块变化类型的分析方法,对2001～2011年沈阳市铁西区大中型(面积大于400m2)城市森林景观动态变化进行分析。结果表明:10年间,铁西区各类型用地相互转化频繁,大中型城市森林斑块总面积和总数量都呈现先增后减的趋势,斑块整体水平向中小型化发展。而工业用地、企事业单位用地和其他用地中的斑块更新度高。研究区域以工业迁移因素为核心,经济发展、人口增长及管理因素成为景观动态变化的主要驱动力。  相似文献   

7.
Studies dealing with community similarity are necessary to understand large scale ecological processes causing biodiversity loss and to improve landscape and regional planning. Here, we study landscape variables influencing patterns of community similarity in fragmented and continuous forest landscapes in the Atlantic forest of South America, isolating the effects of forest loss, fragmentation and patterns of land use. Using a grid design, we surveyed birds in 41 square cells of 100 km2 using the point count method. We used multivariate, regression analyses and lagged predictor autoregressive models to examine the relative influence of landscape variables on community similarity. Forest cover was the primary variable explaining patterns of bird community similarity. Similarity showed a sudden decline between 20 and 40% of forest cover. Patterns of land use had a second order effect; native bird communities were less affected by forest loss in landscapes dominated by tree plantations (the most suitable habitat for native species) than in landscapes dominated by annual crops or cattle pastures. The effects of fragmentation were inconclusive. The trade-off between local extinctions and the invasion of extra-regional species using recently created habitats is probably the mechanism generating the observed patterns of community similarity. Limiting forest loss to 30–40% of the landscape cover and improving the suitability of human-modified habitats will contribute to maintain the structure and composition of the native forest bird community in the Atlantic forest.  相似文献   

8.
Roads are conspicuous components of landscapes and play a substantial role in defining landscape pattern. Previous studies have demonstrated the link between roads and their effects on ecological processes and landscape patterns. Less understood is the placement of roads, and hence the patterns imposed by roads on the landscape in relation to factors describing land use, land cover, and environmental heterogeneity. Our hypothesis was that variation in road density and landscape patterns created by roads can be explained in relation to variables describing land use, land cover, and environmental factors. We examined both road density and landscape patterns created by roads in relation to suitability of soil substrate as road subgrade, land cover, lake area and perimeter, land ownership, and housing density across 19 predominantly forested counties in northern Wisconsin, USA. Generalized least squares regression models showed that housing density and soils with excellent suitability for road subgrade were positively related to road density while wetland area was negatively related. These relationships were consistent across models for different road types. Landscape indices showed greater fragmentation by roads in areas with higher housing density, and agriculture, grassland, and coniferous forest area, but less fragmentation with higher deciduous forest, mixed forest, wetland, and lake area. These relationships provide insight into the complex relationships among social, institutional, and environmental factors that influence where roads occur on the landscape. Our results are important for understanding the impacts of roads on ecosystems and planning for their protection in the face of continued development.  相似文献   

9.
Plant guilds used to measure the relationships between wetlandplant community characteristics and landscape change around 31 depressionalwetlands in central Ohio, USA. Characteristics of certain plant guilds withineach wetland site are correlated with changes in: (a) area of urban land cover,forest, grassland, agriculture, and open-water in the local vicinity ofthe wetland; (b) inter-wetland distance; and (c) wetland size (area).Taxa richness is negatively correlated with inter-wetland distance forall plant guilds, except submersed herbaceous plants. Taxa richness of thesubmersed herbaceous plant guild (usually less than 20% of the totalnumber of plant species at a wetland) is positively correlated with the area ofopen-water in the local landscape and with the areaofthe wetland site itself. Significant positive correlationsalso exist between the area of open-water in the vicinity of the wetlandand the proportion of submersed herbaceous plant taxa at the site, the numberofnative submersed herbaceous plant species, the submersed herbaceous plantperennial-to-annual ratio, and the number ofavian-dispersed submersed herbaceous plant species at a site. Theresults suggest that (a) the dominance of submersed herbaceousplantspecies at a site is related to dispersal constraints between wetlands, and (b)the relatively slower physiological response of woody plants to local landscapechange may result in their contribution to greater ecologicalinertia in the plant community as a whole. For these reasons,relationships between the plant community and land cover change may not alwaysbe observed unless analyzed at the level of plant-guild.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   

10.
为探索国家森林公园建设发展情况并揭示其空间分布规律,本研究采用知识图谱及GIS空间技术对我国国家森林公园的研究进展和空间格局进行了可视化的探索分析.结果 显示:(1)国家森林公园、生态旅游、森林旅游、风景园林、生物多样性、自然保护区、评价、群落结构等是我国森林公园的历史研究热点领域.(2)我国国家森林公园总体呈现东密西疏的空间格局,东北区域及西南区域公园分布较为集中,青海及西藏地区相反.(3)1992-2017年期间国家森林公园的面积得到了更为显著的提升,黑龙江、西藏、新疆、内蒙古4省贡献的面积较多,天津、上海、宁夏、海南4省市对全国国家森林公园建设面积的贡献较小.西部地区国家森林公园的数量有待提升,宁夏、海南2省的国家森林公园总面积有较大理论拓展空间,未来可以加强国家森林公园动态监测评价、森林公园管理制度保障、森林公园建设成效评价、智慧森林公园等方面的研究,以此来推动全国森林公园的全面健康发展.  相似文献   

11.
The present study assesses the spatial distribution of selected land cover classes at two years (1975 and 2000) in a Mediterranean urban area (Athens, Greece) to test the hypothesis that land cover changes determine an increase in the sensitivity of landscape to forest fires on a regional scale. While urban and agricultural areas increased, although with different rates of growth, forests and semi-natural areas decreased in the study area. These changes are reflected in a significant increase of vegetation sensitivity to forest fires measured by the forest fire risk (FR) index developed in the framework of MEDALUS project. The cover classes which contributed the most to the increase of the FR index were crop mosaic, mixed agricultural-natural areas and discontinuous, low-density settlements. Results of the present study indicate that the transformation of the fringe landscape towards low-quality agricultural and pasture areas and fragmented forest patches is potentially detrimental for environmental quality and the ecological fragility of land.  相似文献   

12.
We examined the use of coarse resolution land cover data (USGS LUDA) to accurately discriminate ecoregions and landscape-scale features important to biodiversity monitoring and management. We used land cover composition and landscape indices, correlation and principal components analysis, and comparison with finer-grained Landsat TM data, to assess how well LUDA data discriminate changing patterns across an agriculture-forest gradient in Minnesota, U.S.A. We found LUDA data to be most accurate at general class levels of agriculture and forest dominance (Anderson Level I), but in consistent and limited in ecotonal areas of the gradient and within forested portions of the study region at finer classes (Anderson Level II). We expected LUDA to over-represent major (matrix) cover types and under-represent minor types, but this was not consistent with all classes. 1) Land cover types respond individualistically across the gradient, changing landscape grain as well as their spatial distribution and abundance. 2) Agriculture is not over-represented where it is the dominant land cover type, but forest is over-represented where it is dominant. 3) Individual forest types are under-represented in an open land matrix. 4) Within forested areas, mixed deciduous-coniferous forest is over-represented by several orders of magnitude and the separate conifer and hardwood types under-represented. Across gradual, transitional agriculture-forest areas, LUDA cover class dominance changes abruptly in a stair-step fashion. In general, rare cover types that are discrete, such as forest in agriculture or wetlands or water in forest, are more accurately represented than cover classes having lower contrast with the matrix. Northward across the gradient, important changes in the proportions of conifer and deciduous forest mixtures occur at scales not discriminated by LUDA data. Results suggest that finer-grained data are needed to map within-state ecoregions and discriminate important landscape characteristics. LUDA data, or similar coarse resolution data sources, should be used with caution and the biases fully understood before being applied in regional landscape management. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
The landscape matrix is suggested to influence the effect of habitat fragmentation on species richness, but the generality of this prediction has not been tested. Here, we used data from 10 independent studies on butterfly species richness, where the matrix surrounding grassland patches was dominated by either forest or arable land to test if matrix land use influenced the response of species richness to patch area and connectivity. To account for the possibility that some of the observed species use the matrix as their main or complementary habitat, we analysed the effects on total species richness and on the richness of grassland specialist and non-specialist (generalists and specialists on other habitat types) butterflies separately. Specialists and non-specialists were defined separately for each dataset. Total species richness and the richness of grassland specialist butterflies were positively related to patch area and forest cover in the matrix, and negatively to patch isolation. The strength of the species-area relationship was modified by matrix land use and had a slope that decreased with increasing forest cover in the matrix. Potential mechanisms for the weaker effect of grassland fragmentation in forest-dominated landscapes are (1) that the forest matrix is more heterogeneous and contains more resources, (2) that small grassland patches in a matrix dominated by arable land suffer more from negative edge effects or (3) that the arable matrix constitutes a stronger barrier to dispersal between populations. Regardless of the mechanisms, our results show that there are general effects of matrix land use across landscapes and regions, and that landscape management that increases matrix quality can be a complement to habitat restoration and re-creation in fragmented landscapes.  相似文献   

14.

Context

Climate change is not occurring over a homogeneous landscape and the quantity and quality of available land cover will likely affect the way species respond to climate change. The influence of land cover on species’ responses to climate change, however, is likely to differ depending on habitat type and composition.

Objectives

Our goal was to investigate responses of forest and grassland breeding birds to over 20 years of climate change across varying gradients of forest and grassland habitat. Specifically, we investigated whether (i) increasing amounts of available land cover modify responses of forest and grassland-dependent birds to changing climate and (ii) the effect of increasing land cover amount differs for forest and grassland birds.

Methods

We used Bayesian spatially-varying intercept models to evaluate species- and community-level responses of 30 forest and 10 grassland birds to climate change across varying amounts of their associated land cover types.

Results

Responses of forest birds to climate change were weak and constant across a gradient of forest cover. Conversely, grassland birds responded strongly to changing climatic conditions. Specifically, increasing temperatures led to higher probabilities of localized extinctions for grassland birds, and this effect was intensified in regions with low amounts of grassland cover.

Conclusions

Within the context of northeastern forests and grasslands, we conclude that forests serve as a possible buffer to the impacts of climate change on birds. Conversely, species occupying open, fragmented grassland areas might be particularly at risk of a changing climate due to the diminished buffering capacity of these ecosystems.
  相似文献   

15.
In the last few years, landscape researchers have sought to understand temporal and spatial patterns of landscape changes in order to develop comprehensive models of land cover dynamics. To do so, most studies have used similar methods to quantify structural patterns, usually by comparing various landscape structural indices through time. Whereas the necessity for complementary approaches which might provide insights into landscape dynamics at some finer scale relevant to local managers has been expressed, few studies have proposed alternative methodologies. Moreover, the important relationship between the physical constraints of the landscape and land use dynamics has been seldom emphasized. Here we propose a methodological outline which was applied to the study of a rural landscape of Southern Quebec, Canada, to detect spatial and temporal (1958 to 1993) patterns of land cover changes at field, patch and landscape level. We then relate these patterns to the underlying physical structure of landscape elements using GIS and canonical correspondence analyses. We use the different geomorphological deposit types as stable discriminant factors which may constrain land use.Canonical correspondence analyses showed relations of land use and land use changes to the physical attributes of the landscape elements, whereas spatial analyses revealed very dynamic patterns at finer spatial and temporal scales. They highlighted the fact that not only the physical attributes of the landscape elements but also their spatial configuration were important determinants of land use dynamics in this area. Thus more land use changes occurred at the boundary between geomorphological deposit types than in any other locations. This trend is apparent for specific small-size changes (e.g. forest to crop), but not for the large-size ones (e.g. abandoned land to forest). Although land use changes are triggered by socioeconomic forces in this area, these changes are nevertheless constrained by the underlying physical landscape structure. A thorough comprehension of historical changes will enhance our capability to predict future landscape dynamics and devise more effective landscape management strategies.  相似文献   

16.
As part of the forest landscape, roadside trees are susceptible to multiple stressors that increase potential for tree damage during storm events and contribute to power outages. In exurban areas, decision-making related to the roadside forest is divided among many land ownerships and management entities with diverse objectives. Our objectives were to (1) identify general forest and roadside vegetation management objectives and challenges, (2) identify forest stressors and assess perceived severity and level of concern for forest stressor impacts to the roadside forest, and (3) evaluate manager interrelationships based on management objectives and challenges. We conducted semi-structured interviews with thirty-nine members of the forest management community who manage non-residential and non-industrial tracts of forest land in Connecticut, USA. Improving overall forest health and resilience, wildlife habitat, and forest products were the three most common general forest objectives. The two most frequently identified roadside objectives were public safety and mitigating hazardous conditions. The most common general forest management challenges included workforce limitations, financial constraints, and public perceptions. Support and satisfaction among the public and other stakeholders was the most frequently mentioned roadside forest management challenge. Although participants recognized the importance of roadside vegetation management, many avoided active management along roadsides. Immediate roadside vegetation issues such as public safety were prioritized rather than long-term planning. Stakeholders are constantly orchestrating a balance of numerous objectives as they integrate roadside vegetation considerations into broader forest management.  相似文献   

17.
Citizen science programs have been used to identify and address socio-environmental issues. Environmental participatory monitoring has been particularly effective in providing useful information for forest management and decision-making processes directed at formulating policy. However, recent studies have identified a recurrent participation pattern: citizen science appears to concentrate on affluent municipalities while excluding highly marginalized regions. For this research, a non-parametric analysis of the distribution of observations collected via iNaturalist, a citizens science app for participatory monitoring, is presented. Spearman correlations and a Kruskal-Wallis test were conducted for plant species observations in three states of central Mexico. Results suggest that participatory monitoring patterns are influenced by the marginalization degree of municipalities. Percentage of natural protected areas and forested surface per municipality were also analyzed as variables useful to explain the spatial concentration of participation. Evidence shows that, contrary to observed patterns of exclusion, marginalized municipalities with a designated natural protected area concentrate more participation. Participatory monitoring via citizen science programs is discussed as a valuable tool for developing countries challenged with restricted budgets for environmental management.  相似文献   

18.
Efforts to quantify the effects of riparian buffers on watershed nutrient discharges have been confounded by a commonly used analysis, which estimates buffer potential as the percentage of forest or wetland within a fixed distance of streams. Effective landscape metrics must instead be developed based on a clear conceptual model and quantified at the appropriate spatial scale. We develop new metrics for riparian buffers in two stages of increasing functional specificity to ask: (1) Which riparian metrics are more distinct from measures of whole watershed land cover? (2) Do functional riparian metrics provide different information than fixed-distance metrics? (3) How do these patterns vary within and among different physiographic settings? Using publicly available geographic data, we studied 503 watersheds in four different physiographic provinces of the Chesapeake Bay Drainage. In addition to traditional fixed-distance measures, we calculated mean buffer width, gap frequency, and measures of variation in buffer width using both “unconstrained” metrics and “flow-path” metrics constrained by surface topography. There were distinct patterns of relationship between watershed and near-stream land cover in each physiographic province and strong correlations with watershed land cover confounded fixed-distance metrics. Flow-path metrics were more independent of watershed land cover than either fixed-distance or unconstrained measures, but both functional metrics provided greater detail, interpretability, and flexibility than the fixed-distance approach. Potential applications of the new metrics include exploring the potential for land cover patterns to influence water quality, accounting for buffers in statistical nutrient models, quantifying spatial patterns for process-based modeling, and targeting management actions such as buffer restoration.  相似文献   

19.
The north-central region of Indiana in the Midwestern United States was covered by deciduous forest, but was largely cleared for agriculture during the 1800s. The landscape has experienced tremendous change due to forest restoration, urban expansion, and reservoir construction since the early 1900s. At the same time, ecological health and environmental quality have been dramatically degraded in the region. We used simple landscape indices, such as land proportion, TE, and Shared Edge Length (SEL) between any two classes, to examine changes in the spatial patterning of six land cover types, including agriculture, grassland, closed-canopy forest, open-canopy forest, urban, and water, using aerial photographs dating from 1940 to 1998. The landscape’s domination by agriculture did not change (65% in 1940 and 57% in 1998), but there were net gains in area for closed-canopy forest (79%), urban (256%), and water (125%). Several landscape indices did not change much but SEL between closed-canopy forest and urban increased over seven fold, and SEL between water and urban increased over eight fold from 1940 to 1998. More forestlands and water bodies were exposed to human activities. The clumped pattern of forest, water, and urban in a landscape can be ecologically detrimental and should be considered in future land-use decisions.  相似文献   

20.

Context

Landscape modification is an important driver of biodiversity declines, yet we lack insight into how ongoing landscape change and legacies of historical land use together shape biodiversity.

Objectives

We examined how a history of agricultural land use and current forest fragmentation influence the abundance of red-backed salamanders (Plethodon cinereus). We hypothesized that historical agriculture and fragmentation cause changes in habitat quality and landscape structure that limit abundance.

Methods

We measured salamander abundance at 95 forested sites in New York, USA, and we determined whether sites were agricultural fields within the last five decades. We used a structural equation model to estimate relationships between historical agriculture and salamander abundance mediated by changes in forest vegetation, microclimate, and landscape structure.

Results

Historical agriculture affected salamander abundance by altering forest vegetation at a local scale and forest cover at a landscape scale. Abundance was lowest at post-agricultural sites with low woody vegetation, leaf litter depth, and canopy cover. Post-agricultural sites had limited forest cover in the surrounding landscape historically, and salamander abundance was positively related to historical forest cover, suggesting that connectivity to source populations affects colonization of regenerating forests. Abundance was also negatively related to current forest fragmentation.

Conclusions

Historical land use can have legacy effects on animal abundance on par with effects of ongoing landscape change. We showed that associations between animal abundance and historical land use can be driven by altered site conditions and surrounding habitat area, indicating that restoration efforts should consider local site conditions and landscape context.
  相似文献   

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