Landscape Configuration Metrics Research Articles

Can empirically based model results be fed into mathematical models? MCE for neural network and logistic regression in tourism landscape planning

A wide variety of mathematical and empirical models have been implemented as practical tools for land-use planning, and multilayer perceptron (MLP), logistic regression or LR (mathematical model) and multi-criteria evaluation or MCE (empirical) are among widely applied models. One of the main drawbacks of the mathematical models is that they require dependent data and the process of data collection can be so costly and time-consuming for large areas. As such, we investigated the possibility of providing dependent data set through the MCE method for tourism planning in Golestan Province, Iran. The accuracy of MCE-based algorithms was investigated using ground truth data collected during field observations from early spring up to late summer 2016. The MCE-based and ground-based outputs were investigated and compared for spatial accuracy and connectivity and compactness of the results using receiving operator characteristic (ROC) and landscape configuration metrics. ROC statistics were scored at 0.886, 0.834, 0.82 and 0.814 for ground-based MLP, ground-based LR, MCE-based MLP and MCE-based LR, respectively, showing no meaningful differences between MCE-based and ground-based methods in terms of spatial accuracy. Landscape metrics also indicated that MCE-based methods have resulted in a more connected and manageable pattern for tourism planning. According to the results of this study, MCE can serve as a preliminary approach to define field sampling spots or even as an alternative to field observation efforts in case of limited time and financial resources.

Effects of anthropogenic landscape changes on the abundance and acrodendrophily of Anopheles (Kerteszia) cruzii, the main vector of malaria parasites in the Atlantic Forest in Brazil

BackgroundThe mosquito Anopheles (Kerteszia) cruzii is the main vector of human and simian malaria in the Atlantic Forest. This species is usually abundant in the forests where it occurs, preferring to live and feed on canopies, behaviour known as acrodendrophily. However, in several studies and locations this species has been observed in high density near the ground in the forest. In this study, it was hypothesized that factors associated with anthropogenic landscape changes may be responsible for the variation in abundance and acrodendrophily observed in An. cruzii.MethodsThe study was conducted in a conservation unit in the city of São Paulo, Brazil. Monthly entomological collections were performed from March 2015 to April 2017, and the resulting data were used with data from another study conducted in the same area between May 2009 and June 2010. Mosquitoes were collected from five sites using CDC and Shannon traps. Landscape composition and configuration metrics were measured, and generalized linear mixed-effect models were used to investigate the relationship between these metrics and variations in the abundance and acrodendrophily of An. cruzii.ResultsThe model that showed the best fit for the relationship between landscape metrics and An. cruzii abundance suggests that an increase in the proportion of forest cover leads to an increase in the abundance of this mosquito, while the model that best explained variations in An. cruzii acrodendrophily suggests that an increase in total forest-edge length leads to greater activity by this species at ground level.ConclusionWhile the data indicate that changes in landscape due to human activities lead to a reduction in An. cruzii abundance, such changes may increase the contact rate between this species and humans living on the edges of forest fragments where An. cruzii is found. Future studies should, therefore, seek to elucidate the effect of these landscape changes on the dynamics of Plasmodium transmission in the Atlantic Forest, which according to some studies includes the participation of simian hosts.

Using landscape composition and configuration metrics as indicators of woody vegetation attributes in tropical pastures

Seasonally dry tropical forests in the Neotropics are typically transformed into pasture-dominated landscapes that represent a major threat to habitat biodiversity. Developing alternative management strategies that minimize the loss of native biota in agricultural landscapes is crucial. In a fragmented landscape in Veracruz, Mexico, we analyzed the community attributes of woody vegetation present in pastures in which different types of arboreal elements are common. We hypothesized that different landscape patterns, distinguishable using GIS land-cover maps, would be linked to woody plant diversity and its spatial variation. We created a detailed map of our study area distinguishing six forest cover types. We sampled the woody vegetation within 16 circular plots (100 m radius) each centered on an isolated fig tree and that varied in the amount of arboreal cover and proximity to remnant forest. We used a multimodel-inference approach to assess the relationship between different landscape metrics and woody vegetation response variables. Forest cover within each plot ranged from 3% to 44%. A total of 1777 woody plants (density = 35.4 plants ha−1), belonging to 88 species were recorded. Landscape composition and configuration metrics, particularly the type and amount of arboreal cover, were strong indicators of woody plant richness and abundance, while landscape structural heterogeneity was strongly related to floristic composition. In contrast proximity metrics were weak explanatory variables. Tall canopy forest fragments and isolated trees explained most of the variation in richness and abundance. Results suggest that maintaining 20–40% woody cover within pastures and maximizing the heterogeneity of arboreal elements promotes the conservation of biodiversity in rural landscapes dedicated to livestock. Further, easily obtained landscape metrics can be used as a tool to enhance vegetation assessment and help in the development of more convenient management practices that seek to increase native species richness, while improving landscape connectivity and resilience.

Spatio-temporal dynamics of water quality and their linkages with the watershed landscape in highly disturbed headwater watersheds in China.

The water quality of headwater streams is a worldwide concern because of their critical roles in supplying clean water for drinking and other consumptive uses. Here, we evaluate temporal trends and spatial dynamics of the permanganate index (COD), ammonia-nitrogen (AN), and total phosphorus (TP) for 31 sites in headwater watersheds of the Huai River Basin, China. The seasonal Mann-Kendall test and correlation and variance analyses were applied to long-term time series (2003-2010) of water quality data in order to investigate the patterns of water quality trends, as well as their linkages with the watershed landscape. The results indicated that (1) more than 1/3 of headwater monitoring sites have exhibited either significantly increasing or decreasing trends in COD, AN and TP, while only TP increased for most them; (2) obvious increasing concentration gradients were observed for all water quality parameters along the upstream to the downstream continuum. Such spatial patterns can be highly explained by land cover and landscape configuration metrics. The percent of urban land and urban-related landscape metrics (such as the Landscape Division Index) were the primary explanatory variables for AN, while the aggregation metrics of cropland and urban land cover were the main predictors of COD and TP; (3) historical dynamics of COD, AN, and TP were influenced by land cover transitions. The trends of COD and TP may be attributable to the change in the wetland landscape, while the trends of AN were likely related to changes in forestland area as well as environmental management. Overall, our study determined the spatial and temporal dynamics of water quality parameters in the headwater watersheds and interpreted the possible reasons behind their spatio-temporal dynamics, which can have important implications for sustainable landscape planning as well as headwater watershed management.

Multilevel assessments reveal spatially scaled landscape patterns driving coastal fish assemblages

Ecological research, particularly in marine environments, tends to focus on single habitats and often single spatial scales, and thus not account for ecological processes operating at multiple spatial scales. Here we aim to explore how coastal fish assemblages are influenced by landscape patterns integrating multiple spatial scales, to assess the strength of these associations and to identify the most relevant spatial scales at which these associations occur. We use a multiscale approach through multilevel modelling to evaluate the association of landscape metrics with fish assemblages, at three nested spatial scales, in temperate coastal seascapes composed of seagrass meadows, sandy bottoms and rocky reefs. Landscape composition metrics, expressed as cover of vegetated habitats, significantly influenced fish assemblages at small (metres) and intermediate (hundred of metres) scales, while landscape configuration metrics did it at all three scales assessed (from metres to kilometres). Species richness was only influenced by small scale landscape patterns (cover of rocky reefs, positive association), whereas total abundance was associated with landscape patterns measured at small and intermediate scales, encompassing metrics associated with landscape composition (rocky reef cover, positive association), and those indicating landscape heterogeneity (negative association). Similarly, the abundances of different functional groups were influenced by metrics consistent with their mobility and their ecological and behavioural traits at all the spatial scales assessed. These results show how landscape patterns influence coastal fish assemblages, and particularly show that spatially scaled landscape patterns, measured in complex ecological systems as a whole, act simultaneously but not always equally on species assemblages.

The relationship between urban form and air pollution depends on seasonality and city size.

Understanding how urban form is related to air pollution is important to urban planning and sustainability, but the urban form-air pollution relationship is currently muddled by inconsistent findings. In this study, we investigated how the compositional and configurational attributes of urban form were related to different air pollution measures (PM2.5, API, and exceedance) in 83 Chinese cities, with explicit consideration of city size and seasonality. Ten landscape metrics were selected to quantify urban form attributes, and Spearman's correlation was used to quantify the urban form-air pollution relationship. Our results show that the urban form and air pollution relationship was dominated by city size and moderated by seasonality. Specifically, urban air pollution levels increased consistently and substantially from small to medium, large, and megacities. The urban form-air pollution relationship depended greatly on seasonality and monsoons. That is, the relationship was more pronounced in spring and summer than fall and winter, as well as in cities affected by monsoons. Urban air pollution was correlated more strongly with landscape composition metrics than landscape configuration metrics which seemed to affect only PM2.5 concentrations. Our study suggests that, to understand how air pollution levels are related to urban form, city size and seasonality must be explicitly considered (or controlled). Also, in order to mitigate urban air pollution problems, regional urban planning is needed to curb the spatial extent of built-up areas, reduce the degree of urban fragmentation, and increase urban compactness and contiguity, especially for large and megacities.

Source identification and impact of landscape pattern on riverine nitrogen pollution in a typical urbanized watershed, Beijing, China

This study explored the sources of nitrate and the impact of landscape pattern on nitrogen pollution in the highly urbanized Beiyun River Watershed, China during 2016 by applying a dual stable isotope approach (δ15N-NO3−and δ18O-NO3−) combined with multiple statistical analyses. The sources of riverine nitrate principally originated from manure and sewage, nitrification of soil nitrogen, fertilizer nitrification, and atmospheric deposition. A Bayesian model was used to estimate the source contributions and results showed that manure and sewage were the major contributors to river nitrate with combined proportions of 77.59% and 89.57% in the rainy season and the dry season, respectively. Results from multiple stepwise regression indicated that the typical artificial land use types and landscape configuration metrics reflecting landscape fragmentation related well with riverine nitrogen variables for different seasons (R2>0.6). Industrial land, unused land and patch density of built-up land and road were positively correlated with riverine nitrogen over seasons, whereas the interspersion and juxtaposition index of forest land was negatively related with nitrate. Regulating built-up land and unused land, connecting forest land with other land use types and diminishing discharges of industrial and domestic wastewater would be effective ways to improve urban river water quality.

Are Landscape Configuration Metrics Worth Including When Predicting Specialist and Generalist Bird Species Density? A Case of the Generalised Additive Model Approach

Due to the complexity of factors that influence species density on a large geographical scale, the effectiveness of the species distribution model (SDM) is still debatable. That is why the buffer zone (the area within 100 m from the outside edge of the patch), the core, i.e. (patches excluding the 100 m buffer zone from the patch’s edge) and patch shape are explored in this study to see how they affect the density of habitat specialist and generalist bird species. Two sets of generalised additive models were generated separately for each of the four bird species: One set of models contained landscape configuration metrics as an additional predictor variable, and the other did not. The results showed that models including the core, the buffer zone and the shape of patches turned out to be definitely better than models without them. Specialist species, the Corn bunting and the Wood nuthatch, are more likely to occur in the core of the preferred patches, and they choose those of a simple shape; while generalist species, the Whinchat and the Tree pipit, are more probable to be present in the buffer zone of a more complicated shape. Thus, the results clearly show that specific landscape configuration models can improve the predictive power of SDMs and can be used as an effective tool for predicting species density and functional bird diversity (specialist and generalist). Furthermore, from the applied ecology perspective, detailed landscape configuration metrics can be considered as a surrogate of elusive habitat conditions.

Evaluating the effectiveness of landscape configuration metrics from landscape composition metrics

Although landscape configuration and landscape composition metrics are correlated theoretically and empirically, the effectiveness of configuration metrics from composition metrics has not been explicitly investigated. This study explored to what extent substantial information of configuration metrics increases from certain easily calculated and extensively used composition metrics and how strongly the effectiveness is influenced by different factors. The effectiveness of 12 landscape configuration metrics from the percentage of landscape (PLAND) of each land-use class and patch density (PD) was evaluated through the coefficient of determination (R 2) of multivariate stepwise linear regression analysis of 150 town-based landscape samples from three regions. The different landscape configuration metrics from PLAND and PD presented significantly different performances in terms of effectiveness [the contagion index and aggregation index possess minimal information, and the effective mesh size (MESH) and area-weighted mean patch fractal dimension possess abundant information]. Furthermore, the effectiveness of configuration metrics showed different responses to changing cell sizes and different land-use categorization in different regions (interspersion and juxtaposition index, patch cohesion index, and MESH exhibited large variations in R 2 among the different regions). No single, uniform, consistent characteristic of effectiveness was determined across different factors. This new approach to understanding the effectiveness of configuration metrics helps clarify landscape metrics and is fundamental to landscape metric assessment.

Consequences of a large-scale fragmentation experiment for Neotropical bats: disentangling the relative importance of local and landscape-scale effects

Habitat loss, fragmentation and degradation are widespread drivers of biodiversity decline. Understanding how habitat quality interacts with landscape context, and how they jointly affect species in human-modified landscapes, is of great importance for informing conservation and management. We used a whole-ecosystem manipulation experiment in the Brazilian Amazon to investigate the relative roles of local and landscape attributes in affecting bat assemblages at an interior-edge-matrix disturbance gradient. We surveyed bats in 39 sites, comprising continuous forest (CF), fragments, forest edges and intervening secondary regrowth. For each site, we assessed vegetation structure (local-scale variable) and, for five focal scales, quantified habitat amount and four landscape configuration metrics. Smaller fragments, edges and regrowth sites had fewer species and higher levels of dominance than CF. Regardless of the landscape scale analysed, species richness and evenness were mostly related to the amount of forest cover. Vegetation structure and configurational metrics were important predictors of abundance, whereby the magnitude and direction of response to configurational metrics were scale-dependent. Responses were ensemble-specific with local-scale vegetation structure being more important for frugivorous than for gleaning animalivorous bats. Our study indicates that scale-sensitive measures of landscape structure are needed for a more comprehensive understanding of the effects of fragmentation on tropical biota. Although forest fragments and regrowth habitats can be of conservation significance for tropical bats our results further emphasize that primary forest is of irreplaceable value, underlining that their conservation can only be achieved by the preservation of large expanses of pristine habitat.

Multi-scale analysis of relationship between landscape pattern and urban river water quality in different seasons.

Water quality is highly dependent on the landscape characteristics. In this study, we investigated the relationships between water quality and landscape pattern (composition and configuration) in Huzhou City, China. The water quality variables, including pH, dissolved oxygen (DO), chemical oxygen demand (CODMn), Biochemical Oxygen Demand (BOD), NH3-N, petroleum, dissolved total phosphorus (DTP), and total nitrogen (TN) in low water, normal water and flood periods were identified by investigating 34 sampling sites in Huzhou City during the period from 2001 to 2007. Landscape composition and landscape configuration metrics were calculated for different scales. It was found that scales and seasons both play important role when analyzing the relationships between landscape characteristics of different land use types. The results implied that some water quality parameters such as CODMn, petroleum are more polluted in flood period than the other two seasons at different scales, while DTP and TN are more polluted in low water period. Influences of different landscape metrics on water quality should operate at different spatial scales. The results shown in this paper will effectively provide scientific basis for the policy making in sustainable development of water environment.

Relating landscape to stream nitrate-N levels in a coastal eastern-Atlantic watershed (Portugal)

We apply a linear regression mixed effects model to explore the influence of landscape factors on nitrate-N concentrations in a coastal watershed of Portugal. Landscape composition and configuration metrics, together with variables assessing the physical characteristics of the study area, were used. The analysis was performed using seasonal data from the years 2001 and 2006. The seasonal influence was included as a random effect to account for temporal correlations. Together, the fixed and the random factors explain 78% of the variance, whereas the fixed factors alone explain 10%. Urban, slope, elevation and aggregation index of urban class contribute to the differences found in the NO3−-N concentrations. Urban has the weakest effect, whereas slope and elevation show a conditioned negative effect on nitrate-N. The effect of slope gets stronger for higher standard deviations of elevation and the effect of the standard deviation of elevation, measuring the variation of elevation within a sub-watershed, gets stronger for steeper slopes. Of the configuration class level metrics included in the analysis, only aggregation index of urban played a significant role in the final model, and it revealed to be related to urban percentage. The influence of landscape configuration metrics, though observed by others, was not obvious in this study. Future analysis evaluating the effect of metrics selection could be performed.

Evaluating the Impact of Abrupt Changes in Forest Policy and Management Practices on Landscape Dynamics: Analysis of a Landsat Image Time Series in the Atlantic Northern Forest

Sustainable forest management is based on functional relationships between management actions, landscape conditions, and forest values. Changes in management practices make it fundamentally more difficult to study these relationships because the impacts of current practices are difficult to disentangle from the persistent influences of past practices. Within the Atlantic Northern Forest of Maine, U.S.A., forest policy and management practices changed abruptly in the early 1990s. During the 1970s-1980s, a severe insect outbreak stimulated salvage clearcutting of large contiguous tracts of spruce-fir forest. Following clearcut regulation in 1991, management practices shifted abruptly to near complete dependence on partial harvesting. Using a time series of Landsat satellite imagery (1973-2010) we assessed cumulative landscape change caused by these very different management regimes. We modeled predominant temporal patterns of harvesting and segmented a large study area into groups of landscape units with similar harvest histories. Time series of landscape composition and configuration metrics averaged within groups revealed differences in landscape dynamics caused by differences in management history. In some groups (24% of landscape units), salvage caused rapid loss and subdivision of intact mature forest. Persistent landscape change was created by large salvage clearcuts (often averaging > 100 ha) and conversion of spruce-fir to deciduous and mixed forest. In groups that were little affected by salvage (56% of landscape units), contemporary partial harvesting caused loss and subdivision of intact mature forest at even greater rates. Patch shape complexity and edge density reached high levels even where cumulative harvest area was relatively low. Contemporary practices introduced more numerous and much smaller patches of stand-replacing disturbance (typically averaging <15 ha) and a correspondingly large amount of edge. Management regimes impacted different areas to different degrees, producing different trajectories of landscape change that should be recognized when studying the impact of policy and management practices on forest ecology.

Ecosystem services in peri-urban landscapes: The effects of agricultural landscape change on ecosystem services in Taiwan's western coastal plain

Farmland within urban peri-urban areas can be understood as part of a green infrastructure that provides agro-ecosystem services to benefit the urban population. The growing influence of cities on peri-urban agricultural lands has had significant effects on agricultural land transformation with an associated loss in agro-ecosystem services. The loss of ecosystem services could result in an increase in a city's vulnerability to climate change. More than one sixth of the agricultural lands in Taiwan's western plain have been converted to other uses from 1970 to 2006. We hypothesize that planning guidelines based on landscape ecology could help to plan the optimal spatial configuration of paddy rice land uses in peri-urban areas. In order to study the effects of agricultural landscape changes on ecosystem services in peri-urban areas, this study selected appropriate landscape metrics to assess ecosystem services with landscape composition and configuration metrics for each of the research sites. This research has shown that because agro-ecosystem services are related with the spatial configuration of paddy rice fields, by planning agricultural land use change to optimize spatial configuration, agro-ecosystem services can be maintained. Guidelines are offered to manage agroecosystem services within a context of land use change.

Scale-dependence effects of landscape on seasonal water quality in Xitiaoxi catchment of Taihu Basin, China

Further understanding the mechanisms of landscape-water interactions is of great importance to water quality management in the Xitiaoxi catchment. Pearson's correlation analysis, stepwise multiple regression and redundancy analysis were adopted in this study to investigate the relation between water quality and landscape at the sub-catchment and 200 m riparian zone scales during dry and wet seasons. Landscape was characterized by natural environmental factors, land use patterns and four selected landscape configuration metrics. The obtained results indicated that land use categories of urban and forest were dominant landscape attributes, which influenced water quality. Natural environment and landscape configuration were overwhelmed due to land management activities and hydrologic conditions. In general, the landscape of the 200 m riparian zone appeared to have slightly greater influence on water than did the sub-catchment, and water quality was slightly better explained by all landscape attributes in the wet season than in the dry season. The results suggested that management efforts aimed at maintaining and restoring river water quality should currently focus on the protection of riparian zones and the development of an updated long-term continuous data set and higher resolution digital maps to discuss the minimum width of the riparian zone necessary to protect water quality.

Relating landscape characteristics to non-point source pollution in a typical urbanized watershed in the municipality of Beijing

Landscape characteristics have a substantial effect on non-point source (NPS) pollution. The relationship between landscape characteristics and water quality provides important information for effectively addressing planning and NPS management problems. Multiple stepwise regression analysis and redundancy analysis were integrated to explore the quantitative association between landscape metrics, at both the landscape and class levels, and water quality in the highly urbanized Beiyun River Watershed. The relationship between water quality and the landscape pattern metrics was more significant during the rainy season than after the rainy season. The landscape composition was found to explain 46.9% of the variation in water quality. A total of 60.3% of the variation in water quality could be explained if the landscape configuration metrics were also included in the analysis. This result indicated the importance of the landscape configuration for the water quality of the watershed. Compared with the indices at the landscape level, the class metrics were more effective in predicting water quality. Three metrics, namely, the patch density of water, the largest patch index of forest and the proportion of unused land, could jointly effectively represent the influence of the landscape pattern on the water quality during the rainy season. It is probable that water quality can be improved by maintaining the connectivity of urban rivers, controlling the proportion of unused land and retaining a widespread distribution of unfragmented forest. Furthermore, avoiding the compact distribution of urban land use might reduce the overall emission of pollutants from all forms of transport.

Landscape structure influences space use by white-tailed deer

Variation in space-use patterns among free-ranging mammal populations has been an important area of study in behavioral ecology. We investigated the influence of landscape characteristics associated with landscape fragmentation and diversity on the home-range size of white-tailed deer (Odocoileus virginianus). We evaluated the relative contribution of 3 main land-cover types (forest, agriculture, and rangeland) to the composition of each home range and constructed sex- and season-specific linear regression models using landscape metrics relevant to habitat fragmentation and diversity. Both core and home-range areas were dominated by forest, agriculture, and rangeland. We found that landscape configuration metrics aimed at quantifying landscape fragmentation were good predictors of space use by white-tailed deer and that deer occupied smaller home ranges in highly fragmented areas. Our results indicate that once important cover types are present and patches are sized to meet the resource needs of the individual, configuration of those resource patches influences overall space use. These findings support the assertion that space use by white-tailed deer varies along a gradient of fragmentation.

Quantifying landscape pattern and connectivity in a Mediterranean coastal settlement: the case of the Urla district, Turkey

This study was aimed at analyzing and interpreting changes in landscape pattern and connectivity in the Urla district, Turkey using core landscape metrics based on a 42-year data derived from 1963 CORONA and 2005 ASTER satellite images and ten 1/25,000 topographical maps (1963-2005). The district represents a distinctive example of re-emerged suburbanization in the Izmir metropolitan area. In order to explore landscape characteristics of the study area, nine landscape composition and configuration metrics were chosen as follows: class area, percentage of landscape, number of patches, patch density, largest patch index, landscape shape index, mean patch size, perimeter area fractal dimension, and connectance index. The landscape configurations in the Urla district changed significantly by 2005 in that the process of (sub-)urbanization in the study area evolved from a rural, monocentric urban typology to a more suburban, polycentric morphology. Agricultural, maquis-phrygana, and forest areas decreased, while the built-up, olive plantation and phrygana areas increased. There was nearly a fivefold increase in the built-up areas during the study period, and the connectivity of the natural landscape declined. To prevent further fragmentation, it is important to keep the existing natural land cover types and agricultural areas intact. More importantly, a sustainable development scenario is required that contains a green infrastructure, or an ecological network planning for conservation and rehabilitation of the vital natural resources in the study area.

Influences of watershed landscape composition and configuration on lake‐water quality in the Yangtze River basin of China

AbstractLake‐water quality is highly dependent on the landscape characteristics in its respective watershed. In this study, we investigated the relationships between lake‐water quality and landscape composition and configuration within the watershed in the Yangtze River basin of China. Water quality variables, including pH, electrical conductivity (EC), dissolved oxygen (DO), Secchi depth (SD), NO2−, NO3−, NH4+, TN, TP, chemical oxygen demand (CODMn), chlorophyll‐a (Chl‐a), and trophic state index (TSI), were collected from 16 lakes during the period of 2001–2003. Landscape composition (i.e. the percentage of vegetation, agriculture, water, urban, and bare land) and landscape configuration metrics, including number of patches (NP), patch density (PD), largest patch index (LPI), edge density (ED), mean patch area (MPA), mean shape index (MSI), contagion (CONTAG), patch cohesion index (COHESION), Shannon's diversity index (SHDI), and aggregation index (AI), were calculated for each lake's watershed. Results revealed that the percentage of agriculture was negatively related to NO2−, TN, TP, Chl‐a concentrations, and TSI, while the percentage of urban was significantly correlated with EC, NH4+, and CODMn concentrations. Among landscape‐level configuration metrics, only ED showed significant relationships with TN, TP concentrations, and TSI. However, at the class level, the PD, LPI, ED, and AI of agriculture and urban land uses were significantly correlated with two or more water quality variables. This study suggests that, for a given total area, large and clustered agricultural or urban patches in the watershed may have a greater impact on lake‐water quality than small and scattered ones. Copyright © 2011 John Wiley &amp; Sons, Ltd.

How does forest landscape structure explain tree species richness in a Mediterranean context?

Although the strong relationship between vegetation and climatic factors is widely accepted, other landscape composition and configuration characteristics could be significantly related with vegetation diversity patterns at different scales. Variation partitioning was conducted in order to analyse to what degree forest landscape structure, compared to other spatial and environmental factors, explained forest tree species richness in 278 UTM 10 × 10 km cells in the Mediterranean region of Catalonia (NE Spain). Tree species richness variation was decomposed through linear regression into three groups of explanatory variables: forest landscape (composition and configuration), environmental (topography and climate) and spatial variables. Additionally, the forest landscape characteristics which significantly contributed to explain richness variation were identified through a multiple regression model. About 60% of tree species richness variation was explained by the whole set of variables, while their joint effects explained nearly 28%. Forest landscape variables were those with a greater pure explanatory power for tree species richness (about 15% of total variation), much larger than the pure effect of environmental or spatial variables (about 2% each). Forest canopy cover, forest area and land cover diversity were the most significant composition variables in the regression model. Landscape configuration metrics had a minor effect on forest tree species richness, with the exception of some shape complexity indices, as indicators of land use intensity and edge effects. Our results highlight the importance of considering the forest landscape structure in order to understand the distribution of vegetation diversity in strongly human-modified regions like the Mediterranean.