共查询到20条相似文献，搜索用时 31 毫秒
1.
Road Density and Landscape Pattern in Relation to Housing Density,and Ownership,Land Cover,and Soils 总被引：5，自引：0，他引：5
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
2.
Acknowledgment that the matrix matters in conserving wildlife in human-modified landscapes is increasing. However, the complex
interactions of habitat loss, habitat fragmentation, habitat condition and land use have confounded attempts to disentangle
the relative importance of properties of the landscape mosaic, including the matrix. To this end, we controlled for the amount
of remnant forest habitat and the level of fragmentation to examine mammal species richness in human-modified landscapes of
varying levels of matrix development intensity and patch attributes. We postulated seven alternative models of various patch
habitat, landscape and matrix influences on mammal species richness and then tested these models using generalized linear
mixed-effects models within an information theoretic framework. Matrix attributes were the most important determinants of
terrestrial mammal species richness; matrix development intensity had a strong negative effect and vegetation structural complexity
of the matrix had a strong positive effect. Distance to the nearest remnant forest habitat was relatively unimportant. Matrix
habitat attributes are potentially a more important indicator of isolation of remnant forest patches than measures of distance
to the nearest patch. We conclude that a structurally complex matrix within a human-modified landscape can provide supplementary
habitat resources and increase the probability of movement across the landscape, thereby increasing mammal species richness
in modified landscapes. 相似文献
3.
The landscape matrix modifies the effect of habitat fragmentation in grassland butterflies 总被引：1，自引：0，他引：1
Erik ?ckinger Karl-Olof Bergman Markus Franzén Tomá? Kadlec Jochen Krauss Mikko Kuussaari Juha P?yry Henrik G. Smith Ingolf Steffan-Dewenter Riccardo Bommarco 《Landscape Ecology》2012,27(1):121-131
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
4.
Increasing land ownership fragmentation in the United States is causing concerns with respect to its ecological implications
for forested landscapes. This is especially relevant given that human influence is one of the most significant driving forces
affecting the forest landscape. A method for generating realistic land ownership maps is needed to evaluate the effects of
ownership fragmentation on forest landscapes in combination with other natural processes captured in forest process models.
Ownership patterns from human activities usually generate landscape boundary shapes different from those arising from natural
processes. Spatial characteristics among ownership types – e.g., private, public ownership – may also differ. To address these
issues, we developed the Fragmented Land Ownership Spatial Simulator (FLOSS) to generate ownership patterns that reflect the
Public Land Survey System (PLSS) shapes and various patch size distributions among different types of ownership (e.g., private,
public). To evaluate FLOSS performance, we compared the simulated patterns with various ownership fragmentation levels to
the actual ownership patterns in the Missouri Ozarks by using selected landscape indices. FLOSS generated landscapes with
spatial characteristics similar to actual landscapes, suggesting that it can simulate different levels of ownership fragmentation.
This will allow FLOSS to serve as a feasible tool for evaluating forest management applications by spatially allocating various
management scenarios in a realistic way. The potentials and limitations of FLOSS application are discussed. 相似文献
5.
Romaike S. Middendorp Alvaro J. Pérez Armando Molina Eric F. Lambin 《Landscape Ecology》2016,31(7):1581-1599
Context
Natural regenerating forests are rapidly expanding in the tropics. Forest transitions have the potential to restore biodiversity. Spatial targeting of land use policies could improve the biodiversity benefits of reforesting landscapes.Objective
We explored the relative importance of landscape attributes in influencing the potential of tree cover increase to restore native woody plant biodiversity at the landscape scale.Methods
We developed land use scenarios that differed in spatial patterns of reforestation, using the Pangor watershed in the Ecuadorian Andes as a case study. We distinguished between reforestation through natural regeneration of woody vegetation in abandoned fallows and planted forests through managed plantations of exotic species on previously cultivated land. We simulated the restoration of woody plant biodiversity for each scenario using LANDIS-II, a process-based model of forest dynamics. A pair-case comparison of simulated woody plant biodiversity for each scenario was conducted against a random scenario.Results
Species richness in natural regenerating fallows was considerably higher when occurring in: (i) close proximity to remnant forests; (ii) areas with a high percentage of surrounding forest cover; and (iii) compositional heterogeneous landscapes. Reforestation at intermediate altitudes also positively affected restoration of woody plant species. Planted exotic pine forests negatively affected species restoration.Conclusions
Our research contributes to a better understanding of the recolonization processes of regenerating forests. We provide guidelines for reforestation policies that aim to conserve and restore woody plant biodiversity by accounting for landscape attributes.6.
The spatial distribution of non-native, invasive plants on the landscape is strongly influenced by human action. People introduce non-native species to new landscapes and regions (propagule pressure) as well as increase ecosystem invasibility through disturbance of native ecosystems. However, the relative importance of different landscape drivers of invasion may vary with landscape context (i.e., the types and amounts of surrounding land cover and land use). If so, data collected in one context may not be appropriate for predicting invasion risk across a broader landscape. To test whether independent occurrence datasets suggest similar landscape drivers of invasion, we compared landscape models based on data compiled by the Invasive Plant Atlas of New England (IPANE), which are contributed opportunistically by trained citizen scientists, to models based on Forest Stewardship plans (FSPs), which are located in privately owned and relatively undisturbed forests. We evaluated 16 landscape variables related to propagule pressure and/or disturbance for significant predictors of invasive plant presence based on presence/absence and count regression models. Presence and richness of invasive plants within FSPs was most influenced by proportion of open land and proximity to residential areas, which are both sources of propagules in forest interiors. In contrast, IPANE invasive plant presence and richness for the same area was influenced by distance to roads and streams. These results suggest that landscape drivers of invasion vary considerably depending on landscape context, and the choice of occurrence dataset will strongly influence model results. 相似文献
7.
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
8.
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
9.
We address effects of large-scale forestry on landscape structure and the structure and composition of boreal bird communities in North Sweden. Specifically, we ask: after controlling for the effect of patch size, forest age and tree species composition, is there any residual effect attributable to the reduction in area of old forest? Pairs of landscape blocks (25 by 25 km) were selected to maximize area difference in human-induced disturbance, clear-cut as opposed to semi-natural old forest. Median distance to natural edge (wetlands, open water) from randomly selected points in forest was 250 and 200 m in high and low impact landscapes, respectively, indicating a high degree of ‘natural’ fragmentation of the pristine boreal landscape in the area. By contrast, median distance to clear-cut in uncut forest was 750 and 100 m, respectively. Clear-cuts in high impact landscapes were disproportionally more common in areas with contiguous forest land than in areas with spatially disjunct forest, implicating that forestry increases natural fragmentation of the landscape by subdividing larger forest tracts. Point counts along forestry roads showed that species richness and relative abundance of forest birds were higher in landscapes with low forestry impact. These differences can partly be explained by differences in age composition of forest and composition of tree species. After controlling for patch size, forest age and tree species composition, a significant effect of forestry impact remained for Sibirian species and the Tree pipitAnthus trivialis. Our results thus imply that this group of species and the Tree pipit may be sensitive to forest fragmentation. In contrast to previous Finnish studies, we found relatively small negative effects on relative abundance of species hypothesized to be negatively affected by large-scale clear-cutting forestry. However, our picture of the present does not contradict results from Finnish long-term population studies. Five factors may account for this: 1) clear-cut areas are not permanently transformed into other land use types, 2) planted forests are not completely inhabitable for species preferring older forest, 3) the majority of species in the regional pool are habitat generalists, 4) the region studied is still extensively covered with semi-natural forest, and 5) our study area is relatively close to contiguous boreal forest in Russia, a potential source area for taiga species. 相似文献
10.
In agricultural landscapes, most studies have investigated the influence of the spatial pattern of forest patches on other ecological phenomena and processes, such as animal movement and biodiversity. However, few have focused on explaining the spatial pattern of the forest patches themselves. Understanding how these patterns relate to the processes that generate them is fundamental in developing a sound theory of landscape ecology, and in devising rational management strategies. In this paper, the pattern of the overall forest patches, as well as the pattern of deciduous and coniferous patches in an agricultural landscape of Southern Quebec, Canada, were analyzed and related to landscape physical attributes and land use, using remote sensing, geographic information systems and statistical methods. Results show that the role of landscape physical attributes on forest patch pattern has been modified by land use. In the study area, coniferous or deciduous patches are not associated with a specific surface deposit. In addition, physical attributes explain only a small proportion of the abundance of conifers on past abandoned land compared with land-use factors. Physical attributes only indirectly influence the forest pattern because they strongly influence the land-use practices. Our results reveal a conifer recovery process with the abandonment of agricultural land. On past abandoned land, conifers expand with increasing stand age, mostly by invasion from neighboring coniferous patches. Spatially, coniferous patches are usually located on the margins of the overall forest patches, and they are connected to non-forest land-use types such as crop and pasture, the latter being the most important. By showing the importance of some coniferous forest types that did not exist in the precolonial forest, a new perspective emerges when landscape, especially, land-use dynamics are taken into account. 相似文献
11.
Traditional agricultural mosaic landscapes are likely to undergo dramatic changes through either intensification or abandonment
of land use. Both developmental trends may negatively affect the vascular plant species richness of such landscapes. Therefore,
sustainable land-use systems need to be developed to maintain and re-establish species richness at various spatial scales.
To evaluate the sustainability of specific land-use systems, we need approaches for the effective assessment of the present
species richness and models that can predict the effects on species richness as realistically as possible. In this context,
we present a methodology to estimate and predict vascular plant species richness at the local and the regional scale. In our
approach, the major determinants of vascular plant species richness within the study area are taken into consideration: These
are according to Duelli's mosaic concept the number of habitat types and of habitat patches within area units. Furthermore,
it is based on the relative frequencies of species within habitat types. Our approach comprises six steps: (i) the determination
of present habitat patterns within an observation area, (ii) the creation of a land-use scenario with simulated habitat patterns,
(iii) the determination of species frequencies within habitat types of this area, (iv) a grouping of habitat-specific species,
(v) the estimation of the probabilities for all species (or habitat specialists) to occur, either in stepwise, exponentially
enlarged landscape tracts (local scale), or in the entire observation area (regional scale), and (vi) the validation of the
estimated species numbers. The approach will be exemplified using data from the municipal district of Erda, Lahn-Dill Highlands,
Germany. The current species numbers to be expected on the basis of probability calculations were compared with those recorded
on the basis of extensive field work. This comparison shows that, on the basis of our simple calculations, the current local
plant species richness can be predicted well, with a slight underestimation.
This revised version was published online in May 2005 with corrections to the Cover Date.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Determining what factors explain the distribution of non-native invasive plants that can spread in forest-dominated landscapes
could advance understanding of the invasion process and identify forest areas most susceptible to invasion. We conducted roadside
surveys to determine the presence and abundance of 15 non-native plant species known to invade forests in western North Carolina,
USA. Generalized linear models were used to examine how contemporary and historic land use, landscape context, and topography
influenced presence and abundance of the species at local and regional scales. The most commonly encountered species were
Microstegium vimineum, Rosa multiflora, Lonicera japonica, Celastrus orbiculatus, Ligustrum sinense, and Dioscorea oppositifolia. At the regional scale, distance to city center was the most important explanatory variable, with species more likely present
and more abundant in watersheds closer to Asheville, NC. Many focal species were also more common in watersheds at lower elevation
and with less forest cover. At the local scale, elevation was important for explaining the species’ presence, but forest cover
and land-use history were more important for explaining their abundance. In general, species were more common in plots with
less forest cover and more area reforested since the 1940s. Our results underscore the importance of considering both the
contemporary landscape and historic land use to understand plant invasion in forest-dominated landscapes. 相似文献
13.
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
14.
Context
We address the issue of adapting landscapes for improved insect biodiversity conservation in a changing climate by assessing the importance of additive (main) and synergistic (interaction) effects of land cover and land use with climate.Objectives
We test the hypotheses that ant richness (species and genus), abundance and diversity would vary according to land cover and land use intensity but that these effects would vary according to climate.Methods
We used a 1000 m elevation gradient in eastern Australia (as a proxy for a climate gradient) and sampled ant biodiversity along this gradient from sites with variable land cover and land use.Results
Main effects revealed: higher ant richness (species and genus) and diversity with greater native woody plant canopy cover; and lower species richness with higher cultivation and grazing intensity, bare ground and exotic plant groundcover. Interaction effects revealed: both the positive effects of native plant canopy cover on ant species richness and abundance, and the negative effects of exotic plant groundcover on species richness were greatest at sites with warmer and drier climates.Conclusions
Impacts of climate change on insect biodiversity may be mitigated to some degree through landscape adaptation by increasing woody native vegetation cover and by reducing land use intensity, the cover of exotic vegetation and of bare ground. Evidence of synergistic effects suggests that landscape adaptation may be most effective in areas which are currently warmer and drier, or are projected to become so as a result of climate change.15.
Environmental,historical, and contextual determinants of vegetation cover: a landscape perspective 总被引：1，自引：1，他引：0
We formulated and tested models of relationships among determinants of vegetation cover in two agroforested landscapes of eastern North America (Haut Saint-Laurent, Quebec, Canada) that differed by the spatial arrangement of their geomorphic features and intensity of agricultural activities. Our landscape model compared the woody plots of each landscape in terms of the relative influence of environmental attributes, land use history (1958 – 1997), and spatial context (i.e., proximity of similar or contrasting land cover). Our vegetation model evaluated the relative contribution of the same sets of variables to the distributions of herbs, trees, and shrubs. Relationships were assessed using partial Mantel tests and path analyses. Significant environmental and contextual differences were found between the vegetation plots of the two landscapes, but disturbance history was similar. Our vegetation model confirms the dominant effect of historical factors on vegetation patterns. Whereas land-use history overrides environmental and contextual control for trees, herbaceous and shrub species are more sensitive to environmental conditions. Context is determinant only for understory species in older, less-disturbed plots. Results are discussed in relevance to vegetation dynamics in a landscape perspective that integrates interactions between environmental and human influences. 相似文献
16.
John W. Simpson Ralph E.J. Boerner Michael N. DeMers Leslie A. Berns Francisco J. Artigas Alejandra Silva 《Landscape Ecology》1994,9(4):261-270
This study analyzes the current and historic structure of two contiguous, rural landscapes covering approximately 242 km2 in central Ohio, USA: a till plain landscape with relatively homogeneous topography and soils, and a moraine landscape with greater geomorphological diversity and heterogeneity. These landscapes were chosen because they were both heavily dominated by agriculture during 1900–1940 and were both initially surveyed by the metes-and-bounds system. They differed, however, in the temporal pattern of settlement and development and in the inherent agricultural capability of their soils. We combined analysis of aerial photographs from 1940, 1957, 1971, and 1988 with historical archives and other available mapped data in a GIS data base to facilitate analysis of both spatial and temporal patterns of change. On the moraine, the agricultural matrix decreased over time as forest, urban/suburban areas, and industry increased. In contrast, on the till plain agricultural landcover increased through 1988, with concommitant decreases in upland forest and oak savanna. The moraine landscape exhibited greater diversity and equitability than the till plain on each date. The till plain had its greatest diversity and equitability in 1940, whereas the moraine increased in diversity and equitability during each time period. The undulating topography of the moraine encouraged landcover dynamism rather than stability, whereas the more homogeneous till plain exhibited considerable inertia. Patch and matrix shape remained constant and predominantly angular over the 48 year study period. Differences in the physical environment, especially topography and soil capability, and the socioeconomic environment, especially agricultural policies and patterns of urbanization, resulted in these two contiguous landscapes having different trajectories of change. It is clear from this study that socioeconomic factors must be combined with the physical setting to fully understand patterns of change in human-dominated landscapes. 相似文献
17.
The influence of forest harvesting on landscape spatial patterns and old-growth-forest fragmentation in southeast British Columbia 总被引：2，自引：0，他引：2
Habitat fragmentation is considered one of the major conservation issues of recent decades. We tested predictions of landscape patterns in a 352,253-ha managed forest area in southeast British Columbia. We did this by focussing on forest fragmentation concerns among old-growth, harvest, and wildfire patches in 44 delineated landscapes using patch indices as measures of landscape pattern. We found no significant association between amount of harvesting and 15 old-growth patch indices. Comparisons among patch types revealed that amounts and spatial patterns of harvest patches differed little from amounts and spatial patterns of old-growth patches in control landscapes. Variability indices revealed similar variability between harvest patches and old-growth patches, and more variability between harvest patches and wildfire patches. Little of the evidence gathered in this study supported predictions of fragmentation of old-growth spatial patterns, or predicted differences between harvest spatial patterns and more naturally occurring spatial patterns. We suggest these results could be due to the relatively small amounts of harvesting and old-growth forest in these landscapes, and therefore habitat amount may be a more important factor than spatial configuration of patches in these landscapes. 相似文献
18.
Controlling spatial structure of forested landscapes: a case study towards landscape management 总被引：6，自引：0，他引：6
Emin Z. Baskent 《Landscape Ecology》1999,14(1):83-97
19.
Gregorio I. Gavier-Pizarro Volker C. Radeloff Susan I. Stewart Cynthia D. Huebner Nicholas S. Keuler 《Landscape Ecology》2010,25(10):1505-1518
Forests throughout the US are invaded by non-native invasive plants. Rural housing may contribute to non-native plant invasions
by introducing plants via landscaping, and by creating habitat conditions favorable for invaders. The objective of this paper
was to test the hypothesis that rural housing is a significant factor explaining the distribution of invasive non-native plants
in temperate forests of the Midwestern US. In the Baraboo Hills, Wisconsin, we sampled 105 plots in forest interiors. We recorded
richness and abundance of the most common invasive non-native plants and measured rural housing, human-caused landscape fragmentation
(e.g. roads and forest edges), forest structure and topography. We used regression analysis to identify the variables more
related to the distribution of non-native invasive plants (best subset and hierarchical partitioning analyses for richness
and abundance and logistic regression for presence/absence of individual species). Housing variables had the strongest association
with richness of non-native invasive plants along with distance to forest edge and elevation, while the number of houses in
a 1 km buffer around each plot was the variable most strongly associated with abundance of non-native invasive plants. Rhamnus cathartica and Lonicera spp. were most strongly associated with rural housing and fragmentation. Berberis thumbergii and Rosa multiflora were associated with gentle slopes and low elevation, while Alliaria petiolata was associated with higher cover of native vegetation and stands with no recent logging history. Housing development inside
or adjacent to forests of high conservation value and the use of non-native invasive plants for landscaping should be discouraged. 相似文献
20.
Understanding the determinants of hedgerow plant diversity in agricultural landscapes remains a difficult task, because the
potential drivers affect the complete range of biodiversity components (alpha to gamma diversity). We surveyed herbaceous
plant communities (of a height <1.5 m) in 84 hedgerows in the Seine river floodplain of France. Two types of potential drivers
for species richness, accounting for landscape mosaic and hedgerow network, were recorded at both hedgerow and site scale.
The distribution of species richness through the components of alpha hedgerow diversity (i.e. the average diversity within
a habitat) and gamma hedgerow diversity (i.e. the total diversity across habitats) were assessed using additive partitioning
methods, while the relationship between species diversity and its potential landscape drivers at both scales was modeled using
Generalized Additive Models. Our results indicated that gamma hedgerow diversity is explained by the heterogeneity of the
landscape structure, which is correlated with the mosaic of agricultural land use. At this scale, intrinsic properties of
the configuration of the hedgerow networks have a weak influence on species richness. Alpha hedgerow diversity is also explained
by landscape variables, accounting for both the configuration of agricultural mosaics and hedgerow networks, but to a lesser
extent. Time lags for species responses are shown at both scales, and for the two types of drivers. Extinction or colonization
debt may be indicated at both scales, while the remnant effects of former practices may also be responsible for such patterns
at a local scale. We suggest that hedgerow management should take the specific parameters of both scales into account. At
a local scale, management actions should aim to decrease the influence of adjacent land use when the impact is negative, through
the implementation of extended buffer zones, while at the landscape and farm scales, agri-environmental schemes should be
dedicated to the conservation of specific agricultural land uses. 相似文献