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1.
Kevin Watts Amy E. Eycott Phillip Handley Duncan Ray Jonathan W. Humphrey Christopher P. Quine 《Landscape Ecology》2010,25(9):1305-1318
The focus of biodiversity conservation is shifting to larger spatial scales in response to habitat fragmentation and the need
to integrate multiple landscape objectives. Conservation strategies increasingly incorporate measures to combat fragmentation
such as ecological networks. These are often based on assessment of landscape structure but such approaches fail to capitalise
on the potential offered by more ecologically robust assessments of landscape function and connectivity. In this paper, we
describe a modelling approach to identifying functional habitat networks and demonstrate its application to a fragmented landscape
where policy initiatives seek to improve conditions for woodland biodiversity including increasing woodland cover. Functional
habitat networks were defined by identifying suitable habitat and by modelling connectivity using least-cost approaches to
account for matrix permeability. Generic focal species (GFS) profiles were developed, in consultation with stakeholders, to
represent species with high and moderate sensitivity to fragmentation. We demonstrated how this form of analysis can be used
to aid the spatial targeting of conservation actions. This ‘targeted’ action scenario was tested for effectiveness against
comparable scenarios, which were based on random and clumped actions within the same landscape. We tested effectiveness using
structural metrics, network-based metrics and a published functional connectivity indicator. Targeting actions within networks
resulted in the highest mean woodland area and highest connectivity indicator value. Our approach provides an assessment of
landscape function by recognising the importance of the landscape matrix. It provides a framework for the targeting and evaluation
of alternative conservation options, offering a pragmatic, ecologically-robust solution to a current need in applied landscape
ecology. 相似文献
2.
Dispersal traits determine plant response to habitat connectivity in an urban landscape 总被引：1，自引：1，他引：0
Identification of trait syndromes that make species vulnerable to habitat fragmentation is essential in predicting biodiversity
change. Plants are considered particularly vulnerable if their capacities for persistence in and for dispersal among local
habitats are low. Here we investigated the influence of easily measured functional traits on the presence of 45 plant species
in an urban landscape in north-west Germany where patches were separated by distances consistent with regular plant dispersal
range. To describe the spatial configuration of patches we calculated species-specific patch connectivities. Then we assessed
plant connectivity responses in distribution models calculated from connectivities and environmental predictors. Twenty (45%)
of the analysed species showed a positive connectivity response after accounting for species-specific habitat requirements.
These species differed from non-responsive species by functional traits associated with dispersal, including reduced seed
numbers and higher terminal velocities relative to non-responsive species. Persistence traits played however no role which
we attribute to the environmental conditions of urban habitats and their spatiotemporal characteristics. Our study underlines
that even ruderal plants experience dispersal limitation and demonstrates that easily measured functional traits may be used
as indicators of fragmentation vulnerability in urban systems allowing generalizations to larger species sets. 相似文献
3.
Although urban habitats contribute to the conservation of species diversity, urbanization has significantly reduced biodiversity by causing environmental changes such as habitat loss and fragmentation. Therefore, research on urban biodiversity studies has become increasingly important. Historical heritage sites are recognized as important habitats in remnant green spaces in urban areas. We aimed to evaluate the role of historical sites in conserving biodiversity in urban areas. As the land in these historical sites is not modified, they have the potential to conserve biodiversity through continued maintenance activities such as mowing and tree cutting. In Japan, Tamagawa-josui, a waterway that runs from west to east through the Tokyo megacity (35° 40′ N, 139° 25′ E), has been recognized as a civil engineering heritage landmark that preserves water utilization technology from the early modern period (1600s, Edo-era). The present study examined the relationships between plant diversity and green space in a historic site of a megacity (i.e., Tamagawa-josui) and determined the factors that influence plant diversity. Specifically, we examined the relationships between plant species indices (species richness and species compositions) and environmental factors (management, environmental conditions, and landscape factors). The present study analyzed spatial changes in the plant species composition in Tamagawa-josui. We demonstrated that tree canopy openness was positively correlated with plant species richness, and the increased disturbance associated with developing historical sites as urban parks was negatively correlated with native plant species richness. In addition, there was significant species turnover in the plant community from upstream to downstream in Tamagawa-josui, which could largely be explained by spatial factors. We demonstrated that historical sites can provide potential habitats for the conservation of the plant species diversity, which is based on the effectiveness of the management of their vegetation. 相似文献
4.
Urban areas are a particular landscape matrix characterized by a fine-grained spatial arrangement of very diverse habitats
(urban mosaic). We investigated arthropods to analyse biodiversity-habitat associations along five environmental gradients
(age, impervious area, management, configuration, composition) in three Swiss cities (96 study sites). We considered total
species richness and species richness within different functional groups (zoophagous, phytophagous, pollinator, low mobility,
and high mobility species). Information theoretical model selection procedures were applied and predictions were calculated
based on weighted models. Urban areas yielded on average 284 arthropod species (range: 169–361), with species richness correlating
mostly with heterogeneity indices (configuration and composition). Species richness also increased with age of urban settlement,
while enlarged proportions of impervious area and intensified habitat management was negatively correlated. Functional groups
showed contrasted, specific responses to environmental variables. Overall, we found surprisingly little variation in species
richness along the gradients, which is possibly due to the fine-grained spatial interlinkage of good (heterogeneous) and bad
(sealed) habitats. The highly fragmented nature of urban areas may not represent a major obstacle for the arthropods currently
existing in cities because they have probably been selected for tolerance to fragmentation and for high colonisation potential.
Given that built areas are becoming denser, increasing spatial heterogeneity of the urban green offers potential for counteracting
the detrimental effects of densification upon urban biodiversity. By quantifying the expected effects along environmental
gradients, this study provides guidance for managers to set priorities when enhancing urban arthropod species richness. 相似文献
5.
Leonie K. Fischer Moritz von der Lippe Ingo Kowarik 《Urban Forestry & Urban Greening》2013,12(3):263-272
Urbanisation is an important driver of biodiversity loss, also contributing to habitat loss and fragmentation of grasslands at the urban-rural interface. While urban green spaces are known to include many grassland habitats, it is uncertain to what extent urban land use types harbour grasslands of special conservation interest and whether patch characteristics and connectivity of these differ from grasslands on agricultural land. By relating the city-wide biotope mapping to the land use mapping of Berlin, Germany, we assessed (1) to which specific urban land use types the major grassland biotope types belong, (2) differences in patch characteristics and connectivity, and (3) the conservation value of grassland patches at a typological level by means of their legal protection status. Grasslands cover 5% of Berlin's surface, and 43% of that area is assigned to legally protected grassland types. The majority of legally protected grassland (71%) lies on urban land opposed to 29% on agricultural land. Airports and historic parks, which only cover 2% of land in Berlin, contain one-third of all protected dry grasslands. Wet grassland is more confined to agricultural land. In airports and agricultural areas, grassland patches are larger but of a more complex shape than those in historic parks. In airports, grassland patches show greater connectivity as they are situated in grassland-dominated surroundings. Grassland in historic parks appears to be more vulnerable due to smaller patch sizes and higher fragmentation. The example of Berlin demonstrates that the urban green infrastructure can clearly contribute to grassland conservation and may thus partially compensate for the decline of traditional grasslands in cultural landscapes. It will be important to involve residents and landowners in urban grassland conservation and management because most grassland of special conservation interest (57%) was found outside of conservation areas. 相似文献
6.
The study of links between bird species richness and forest fragmentation contributes to a better understanding of landscape
biodiversity. Difficulties arise from the necessity to deal with multiple non-linear relationships between the involved variables.
Neural network models provide an interesting solution thanks to their internal set of non-linear neuron-like components. Their
ability is well established for prediction, but their complex structure limits the understanding of underlying processes.
To open the ‘black box’ and get a more transparent ‘glass box’ model, we selected a simple neural network (2 inputs, 1 hidden
layer with 3 neurons and 1 output neuron), that improves the prediction of birds species richness (lower root mean square
error) compared to linear, log-linear and logistic models, and simple enough to analyze its internal components and identify
patterns in the data. The first hidden neuron provided a sigmoid relationship related to the forest area, the second was like
a Boolean operator separating two groups according to the distance to the nearest source forest larger than 100 ha, and the
third acted on the smallest isolated woodlots. We revealed a group of isolated woodlots with a higher species richness than
less isolated woodlots for a given forest area. This result, unexpected according to the literature, was not obvious in the
raw data, and could be explained by a regional differentiation in fragmentation history. Our neural network showed its ability
to improve prediction accuracy in respect to other models, to remain ecologically understandable and to give new insights
into data exploration. 相似文献
7.
Milena F. Diniz Ricardo B. Machado Arthur A. Bispo Paulo De M. Júnior 《Landscape Ecology》2018,33(11):1911-1923
Context
The umbrella approach applied to landscape connectivity is based on the principle that the conservation or restoration of the dispersal habitats for some species also can facilitate the movement of others. Species traits alone do not seem to be enough to identify good connectivity umbrella species, showing the need to investigate the influence of additional factors on this property.Objectives
We test whether the potential of a species as a connectivity umbrella can be influenced by landscape composition and configuration.Methods
We simulated movement routes for eight hypothetical species in artificial patchy landscapes with different levels of fragmentation, habitat amount and matrix permeability. We determined the effectiveness of the connectivity umbrella of the virtual species using pairwise intersections of important habitats for their movements in all landscapes.Results
The connectivity umbrella performance of all species was affected by the interaction of fragmentation level and habitat amount. In general, species performance increased with decreasing fragmentation and increasing habitat amount. In most landscapes and considering the same dispersal threshold, species able to move more easily through the matrix showed higher umbrella performance than those for which the matrix offered greater resistance.Conclusions
The connectivity umbrella is not a static feature that depends only on the species traits, but rather a dynamic property that also varies according to the landscape attributes. Therefore, we do not recommend spatial transferability of the connectivity umbrella species identified in a landscape to others that have divergent levels of fragmentation and habitat quantity.8.
Habitat loss and fragmentation of natural and semi-natural habitats are considered as major threats to plant species richness.
Recently several studies have pinpointed the need to analyse past landscape patterns to understand effects of fragmentation,
as the response to landscape change may be slow in many organisms, plants in particular. We compared species richness in continuously
grazed and abandoned grasslands in different commonplace rural landscapes in Sweden, and analysed effects of isolation and
area in three time-steps (100 and 50 years ago and today). Old cadastral maps and aerial photographs were used to analyse
past and present landscape patterns in 25 sites. Two plant diversity measures were investigated; total species richness and
species density. During the last 100 years grassland area and connectivity have been reduced by about 90%. Present-day habitat
area was positively related to total species richness in both habitats. There was also a relationship to habitat area 50 years
ago for continuously grazed grasslands. Only present management was related to species density: continuously grazed grasslands
had the highest species density. There were no relationships between grassland connectivity, present or past, and any diversity
measure. We conclude that landscape history is not directly important for present-day plant diversity patterns in ordinary
landscapes, although past grassland management is a prerequisite for the grassland habitats that can be found there today.
It is important that studies are conducted, not only in very diverse landscapes, but also in managed landscapes in order to
assess the effects of fragmentation on species. 相似文献
9.
Here we present a spatial planning approach for the implementation of adaptation measures to climate change in conservation
planning for ecological networks. We analyse the wetland ecosystems of the Dutch National Ecological Network for locations
where the effectiveness of the network might be weakened because of climate change. We first identify potential dispersal
bottlenecks where connectivity might be insufficient to facilitate range expansions. We then identify habitat patches that
might have a too low carrying capacity for populations to cope with additional population fluctuations caused by weather extremes.
Finally, we describe the spatial planning steps that were followed to determine the best locations for adaptation measures.
An essential part of our adaptation strategy is to concentrate adaptation measures in a ‘climate adaptation zone’. Concentrating
adaptation measures is a cost-effective planning strategy, rendering the largest benefit per area unit. Measures are taken
where abiotic conditions are optimal and measures to enhance the spatial cohesion of the network are taken close to existing
areas, thus creating the highest possible connectivity with the lowest area demands. Another benefit of a climate adaptation
zone is that it provides a spatial protection zone where activities that will have a negative impact on ecosystem functioning
might be avoided or mitigated. The following adaptation measures are proposed within the climate adaptation zone: (1) link
habitat networks to enable species to disperse from present to future suitable climate zones, (2) enlarge the carrying capacity
by either enlarging the size of natural areas or by improving habitat quality to shorten population recovery after disturbances,
(3) increase the heterogeneity of natural areas, preferably by stimulating natural landscape-forming processes, to avoid large
synchronised extinctions after extreme weather events. The presented approach can be generalised to develop climate adaptation
zones for other ecosystem types inside or outside Europe, where habitat fragmentation is a limiting factor in biodiversity
responses to climate change. 相似文献
10.
Connectivity providers for semi-aquatic vertebrates: the case of the endangered otter in Italy 总被引：1，自引：0，他引：1
Maria Laura Carranza Evelina D’Alessandro Santiago Saura Anna Loy 《Landscape Ecology》2012,27(2):281-290
Modeling habitat connectivity for conservation of semi-aquatic vertebrates is a particularly challenging task, due to the
fine-scale and linear distribution of riverine habitats and to the capacity of species to move both on freshwater and terrestrial
realms. We showed how the integrated analytical framework provided by the habitat availability (reachability) metrics and
their fractions can be used to effectively evaluate the distinctive roles and contributions of both habitat patches (aquatic
and riparian) and linkage areas (permeable land matrix) to the connectivity and functioning of a complex system composed of
multiple river catchments. Analysis focused on the Eurasian otter (Lutra lutra L.), one of the most endangered mammals in Italy. We developed a network connectivity model based on suitable otter habitats
and multiple least-cost paths between catchments. A graph analytical approach was used to identify critical nodes and links
for the potential expansion and long-term viability of the species in the region. Our results showed that few basins concentrate
most of the importance for sustaining the overall habitat connectivity, due to the extension of suitable habitats they contain,
their strong connections with other basins, and their importance as stepping stones that uphold ecological fluxes between
otherwise weakly connected habitats. The potential contribution of each basin to enhance the dispersal and expansion of otters
in the area strongly depended on the key functional paths (sequences of links and nodes) among the catchments. We identified
vacant basins that could be colonized by otters in the near future, and connecting areas in the intermediate matrix that might
be preferentially used to conduct and promote dispersal movements and gene flow in the area. The novel approach here adopted
could be easily extended to other semiaquatic species and catchment systems, offering a management strategy to preserve the
hydrographic network as an integrated system, as well as a joint evaluation of the role of both the river courses and the
matrix in between in a single landscape model. 相似文献
11.
Although many empirical and theoretical studies have elucidated the effects of habitat fragmentation on the third trophic level, little attention has been paid to the impacts of this driver on more generalist groups of non-hymenopteran parasitoids. Here, we used the highly-diverse group of tachinid flies as an alternative model to test the effects of landscape fragmentation on insect parasitoids. Our aims were: (i) to evaluate the relative importance of habitat area and connectivity losses and their potential interaction on tachinid diversity, (ii) to test whether the effects of habitat fragmentation changes seasonally, and (iii) to further assess the effect of habitat diversity on tachinid diversity and whether different parasitoid-host associations modify the species richness response to fragmentation. In 2012 a pan-trap sampling was conducted in 18 semi-natural grasslands embedded in intensive agricultural landscapes along statistically orthogonal gradients of habitat area, connectivity and habitat diversity. We found an interaction between habitat area and connectivity indicating that tachinid abundance and species richness were more negatively affected by habitat loss in landscapes with low rather than with relatively large habitat connectivity. Although tachinid communities exhibited large within-year species turnover, we found that the effects of landscape fragmentation did not change seasonally. We found that habitat diversity and host association did not affect tachinid species diversity. Our results have important implications for biodiversity conservation as any attempts to mitigate the negative effects of habitat loss need to take the general level of habitat connectivity in the landscape into account. 相似文献
12.
Eben N. Broadbent Angélica M. Almeyda Zambrano Rodolfo Dirzo William H. Durham Laura Driscoll Patrick Gallagher Rosalyn Salters Jared Schultz Angélica Colmenares Shannon G. Randolph 《Landscape Ecology》2012,27(5):731-744
Development in biodiversity rich areas is of global concern. While development may lead to socioeconomic benefits, this often
comes concomitant with biodiversity loss and deforestation. Biodiversity rich areas present the opportunity for both improvements
in socioeconomic conditions and conservation; however numerous challenges exist. Costa Rica’s Manuel Antonio National Park
presents an ideal case study to investigate the balance between alternative forms of development which have contrasting environmental
impacts. The Manuel Antonio region is a highly dynamic landscape experiencing deforestation, from agriculture, cattle ranching
and oil palm plantations; and also reforestation from abandonment of land holdings and nature oriented tourism. Landscape
dynamics are closely intertwined with the livelihoods and perspectives on biodiversity conservation of local communities,
determining ecological sustainability. We use an analysis combining multi-temporal remote sensing of land cover dynamics from
1985 to 2008 with questionnaire data from local families on their socioeconomic status, perspectives on conservation, and
perceived changes in local wildlife populations. Our results show that, while regeneration occurred and forest fragmentation
in the area decreased from 1985 to 2008, Manuel Antonio National Park is rapidly becoming isolated. Decreasing ecological
connectivity is related to the rapid expansion of oil palm plantations adjacent to the park and throughout the lowland areas.
Perceived decreases in wildlife abundance and compositional change are evident throughout the area, with local communities
attributing this primarily to illegal hunting activities. Nature based tourism in the area presents an effective strategy
for conservation, including reductions in hunting, through increased valuation of biodiversity and protected areas, and socioeconomic
advantages. However, without urgent efforts to limit deforestation and preserve the remaining forested corridor connecting
the park to core primary forest, the ability to maintain biodiversity in the park will be reduced. 相似文献
13.
Biodiversity conservation in economic areas like ports has recently become more important in the European Union due to a stricter
interpretation of nature protection laws. In this study we develop a planning and design strategy—the ‘habitat backbone’—with
which to support the long-term survival of pioneer species that occur in ports and have low dispersal abilities. For those
species, long-term survival in port areas is uncertain because supply of their habitats (on vacant lots) is capricious and
depends on land use dynamics. By gaining knowledge about spatial and temporal characteristics of these dynamics we were able
to develop a solution to conserve such species. Our solution is based on the creation of permanent habitat—defined as a ‘backbone’—on
(semi-) public land with an overall carrying capacity sufficient to support persistent populations. This best ensures long-term
survival, and the backbone may also act as refugium. Satellite populations that emerge on adjacent vacant lots will thereby
add to the persistence of the overall metapopulation. Management of permanent habitat is focused on retaining early-successional
stages of vegetation. Implementing this strategy in the case of the natterjack toad in the Port of Antwerp taught us that
realization of a habitat backbone is possible only if landowners, local governments and environmental NGOs cooperate. In the
case at hand, such cooperation resulted in a plan that should ensure a coherent and persistent habitat network in which a
chorus of some 1,400 natterjack toads could be accommodated—more than the number of toads currently observed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Luis Ruiz Niki Parikh Lucas J. Heintzman Steven D. Collins Scott M. Starr Christopher K. Wright Geoffrey M. Henebry Natasja van Gestel Nancy E. McIntyre 《Landscape Ecology》2014,29(3):507-516
We quantified fluctuations in the status of individual patches (wetlands) in supporting connectivity within a network of playas, temporary wetlands of the southern Great Plains of North America that are loci for regional biodiversity. We used remote sensing imagery to delineate the location of surface waters in >8,000 playa basins in a ~31,900 km2 portion of Texas and quantified connectivity in this region from 2007 to 2011. We ranked playas as stepping-stones, cutpoints, and hubs at different levels of environmental conditions (regionally wet, dry, and average periods of precipitation) for dispersal distances ranging from 0.5 to 34 km, representing a range of species’ vagilities, to provide baseline dynamics within an area likely to experience disrupted connectivity due to anthropogenic activities. An individual playa’s status as a stepping-stone, cutpoint, or hub was highly variable over time (only a single playa was a top 20 stepping-stone, cutpoint, or hub in >50 % of all of the dates examined). Coalescence of the inundated playa network usually occurred at ≥10 km dispersal distance and depended on wetland density, indicating that critical thresholds in connectivity arose from synergistic effects of dispersal ability (spatial scale) and wet playa occurrence (a function of precipitation). Organisms with dispersal capabilities limited to <10 km routinely experienced effective isolation during our study. Connectivity is thus a dynamic emergent landscape property, so management to maintain connectivity for wildlife within ephemeral habitats like inundated playas will need to move beyond a patch-based focus to a network focus by including connectivity as a dynamic landscape property. 相似文献
15.
Fragmentation of China’s landscape by roads and urban areas 总被引：1，自引：0，他引：1
Taian Li Fraser Shilling James Thorne Fengmin Li Heidi Schott Ryan Boynton Alison M. Berry 《Landscape Ecology》2010,25(6):839-853
China’s major paved road-ways (national roads, provincial roads, and county roads), railways and urban development are rapidly
expanding. A likely consequence of this fast-paced growth is landscape fragmentation and disruption of ecological flows. In
order to provide ecological information to infrastructure planners and environmental managers for use in landscape conservation,
land-division from development must be measured. We used the effective-mesh-size (Meff) method to provide the first evaluation of the degree of landscape division in China, caused by paved roads, railways, and
urban areas. Using Meff, we found that fragmentation by major transportation systems and urban areas in China varied widely, from the least-impacted
west to the most impacted south and east of China. Almost all eastern provinces and counties, especially areas near big cities,
have high levels of fragmentation. Several eastern-Chinese provinces and biogeographic regions have among the most severe
landscape fragmentation in the world, while others are comparable to the least-developed areas of Europe and California. Threatened
plant hotspots and areas with high mammal species diversity occurred in both highly fragmented and less fragmented areas,
though future road development threatens already moderately divided landscapes. To conserve threatened biodiversity and landscapes,
we recommend that national and regional planners in China consider existing land division before making decisions about further
road development and improvement. 相似文献
16.
Fraser Devaughn L. Ironside Kirsten Wayne Robert K. Boydston Erin E. 《Landscape Ecology》2019,34(5):1097-1115
Context
Urbanization is a substantial force shaping the genetic and demographic structure of natural populations. Urban development and major highways can limit animal movements, and thus gene flow, even in highly mobile species. Characterizing varying species responses to human activity and fragmentation is important for maintaining genetic continuity in wild animals and for preserving biodiversity. As one of the only common and wide-ranging large wild herbivores in much of urban North America, deer play an important ecological role in urban ecosystems, yet the genetic impacts of development on deer are not well known.
ObjectivesWe assessed genetic connectivity for mule deer to understand their genetic response to habitat fragmentation, due to development and highway barriers, in an increasingly urbanized landscape.
MethodsUsing non-invasive sampling across a broad region of southern California, we investigated genetic structure among several natural areas that were separated by major highways and applied least-cost path modelling to determine if landscape context and highway attributes influence genetic distance for mule deer.
ResultsWe observed significant yet variable differentiation between subregions. We show that genetic structure corresponds with highway boundaries in certain habitat patches, and that particular landscape configurations more greatly limit gene flow between patches.
ConclusionsAs a large and highly mobile species generally considered to be well adapted to human activity, mule deer nonetheless showed genetic impacts of intensive urbanization. Because of this potential vulnerability, mule deer and other ungulates may require further consideration for effective habitat management and maintenance of landscape connectivity in human-dominated landscapes.
相似文献17.
Mediterranean landscapes are suffering two opposing forces leading to large-scale changes in species distribution: land abandonment
of less productive areas and an increase in wildfire impact. Here, we test the hypothesis that fires occurred in recent decades
drive the pattern of expansion of early-successional, open-habitat bird species by aiding in the process of colonisation of
newly burnt areas. The study was carried out in Catalonia (NE Spain). We selected 44 burnt sites occurring between 2000 and
2005 to model colonisation patterns under different assumptions of potential colonisers’ sources and evaluated the colonisation
estimates with empirical data on six bird species especially collected for this purpose. We first defined three landscape
scenarios serving as surrogates of potential colonisers’ sources: open-habitats created by fire, shrublands and farmlands.
Then, we used a parameter derived from a functional connectivity metric to estimate species colonization dynamics on the selected
sites by each particular scenario. Finally, we evaluated our colonisation estimates with the species occurrence in the studied
locations by using generalized linear mixed models. The occurrence of the focal species on the newly burnt sites was significantly
related to the connectivity patterns described by both the recent fire history and the other open-habitat types generated
by a different type of disturbance. We suggest that land use changes in recent decades have produced a shift in the relative
importance of habitats acting as reservoirs for open-habitat bird species dynamics in Mediterranean areas. Before the middle
of the twentieth century species’ reservoirs were probably constituted by relatively static open habitats (grassland and farmland),
whereas afterwards they likely consist of a shifting mosaic of habitat patches where fire plays a key role as connectivity
provider and largely contributes to the maintenance of species persistence. 相似文献
18.
Lisa Freudenberger Peter R. Hobson Slaven Rupic Guy Pe’er Martin Schluck Julia Sauermann Stefan Kreft Nuria Selva Pierre L. Ibisch 《Landscape Ecology》2013,28(7):1353-1369
The expansion of roads, and the subsequent changes to the surrounding landscape not only lead to landscape fragmentation but also have been shown to be a key driver of biodiversity loss and ecosystem degradation. Local declines of species abundance as well as changes in animal behaviour have drawn attention to wider ecosystem effects including altered species composition and a degradation of ecosystem functioning. However, methods for measuring and quantifying the distribution and environmental impacts of roads are not yet fully developed. We present a new technique for assessing the potential impacts of roads on biodiversity using a spatial road disturbance index (SPROADI). The index is calculated from three sub-indices: traffic intensity as a measure of traffic volume per time and space; vicinity impact, which is the assessment of edge effect of roads on adjacent habitats (the road-effect zone); and fragmentation grade, which provides an indication of the degree to which the landscape is intersected by roads. SPROADI was then tested using data from the Federal State of Brandenburg in north-eastern Germany. A sensitivity analysis was carried out on the results to assess the robustness of the index. The findings revealed expected patterns of high road disturbance in urban and peri-urban landscapes surrounding Berlin. Less obvious were the high levels of road density and impacts in forest plantations across the southern region of Brandenburg, and low levels of road disturbance in agricultural crop lands of the north-western region. Results were variable for areas under some form of protection. The only national park displayed substantially lower SPROADI values in contrast to the surrounding non-protected areas whilst other protected area categories, which were landscape conservation areas and nature parks, revealed SPROADI values that were equally high as those for non-protected areas. The results of this study demonstrate the strengths and potential applications of SPROADI as a quantitative means for identifying low-traffic areas in the context of conservation and sustainable transport planning. 相似文献
19.
Mira Kattwinkel Barbara Strauss Robert Biedermann Michael Kleyer 《Landscape Ecology》2009,24(7):929-941
The importance of the spatial as well as the temporal structure of habitat patches for urban biodiversity has been recognised,
but rarely quantified. In dynamic environments the rate of habitat destruction and recreation (i.e. the landscape turnover
rate), the minimum amount of potential habitat, its spatial configuration as well as the environmental conditions determining
habitat quality are crucial factors for species occurrence. We analysed species responses to environmental parameters and
to the spatio-temporal configuration of urban brownfield habitats in a multi-species approach (37 plant and 43 insect species).
Species presence/absence data and soil parameters, site age, vegetation structure and landscape context were recorded by random
stratified sampling at 133 study plots in industrial areas in the city of Bremen (Germany). Based on the field data, we predicted
species occurrences by species distribution models using a multi-model inference approach. Predicted species communities were
driven by successional age both at the scale of a single building lot and at the landscape scale. Minimum average succession
time of brownfield habitats required to support all and especially regionally rare species depended on the proportion of available
open space; the larger the potential habitat area the faster the acceptable turnover. Most plant, grasshopper, and leafhopper
species modelled could be maintained at an intermediate turnover rate (mean age of 10–15 years) and a proportion of open sites
of at least 40%. Our modelling approach provides the opportunity of inferring optimal spatio-temporal landscape configurations
for urban conservation management from patch scale species-environment relationships. The results indicate that urban planning
should incorporate land use dynamics into the management of urban biodiversity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.