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1.
Context
Quantifying variability in landscape-scale surface water connectivity can help improve our understanding of the multiple effects of wetlands on downstream waterways.Objectives
We examined how wetland merging and the coalescence of wetlands with streams varied both spatially (among ecoregions) and interannually (from drought to deluge) across parts of the Prairie Pothole Region.Methods
Wetland extent was derived over a time series (1990–2011) using Landsat imagery. Changes in landscape-scale connectivity, generated by the physical coalescence of wetlands with other surface water features, were quantified by fusing static wetland and stream datasets with Landsat-derived wetland extent maps, and related to multiple wetness indices. The usage of Landsat allows for decadal-scale analysis, but limits the types of surface water connections that can be detected.Results
Wetland extent correlated positively with the merging of wetlands and wetlands with streams. Wetness conditions, as defined by drought indices and runoff, were positively correlated with wetland extent, but less consistently correlated with measures of surface water connectivity. The degree of wetland–wetland merging was found to depend less on total wetland area or density, and more on climate conditions, as well as the threshold for how wetland/upland was defined. In contrast, the merging of wetlands with streams was positively correlated with stream density, and inversely related to wetland density.Conclusions
Characterizing the degree of surface water connectivity within the Prairie Pothole Region in North America requires consideration of (1) climate-driven variation in wetness conditions and (2) within-region variation in wetland and stream spatial arrangements.2.
Petra Janečková Štěpán Janeček Jitka Klimešová Lars Götzenberger Jan Horník Jan Lepš Francesco de Bello 《Landscape Ecology》2017,32(4):791-805
Context
Landscape fragmentation significantly affects species distributions by decreasing the number and connectivity of suitable patches. While researchers have hypothesized that species functional traits could help in predicting species distribution in a landscape, predictions should depend on the type of patches available and on the ability of species to disperse and grow there.Objectives
To explore whether different traits can explain the frequency of grassland species (number of occupied patches) and/or their occupancy (ratio of occupied to suitable patches) across a variety of patch types within a fragmented landscape.Methods
We sampled species distributions over 1300 grassland patches in a fragmented landscape of 385 km2 in the Czech Republic. Relationships between functional traits and species frequency and occupancy were tested across all patches in the landscape, as well as within patches that shared similar management, wetness, and isolation.Results
Although some traits predicting species frequency also predicted occupancy, others were markedly different, with competition- and dispersal-related traits becoming more important for occupancy. Which traits were important differed for frequency and occupancy and also differed depending on patch management, wetness, and isolation.Conclusions
Plant traits can provide insight into plant distribution in fragmented landscapes and can reveal specific abiotic, biotic, and dispersal processes affecting species occurrence in a patch type. However, the importance of individual traits depends on the type of suitable patches available within the landscape.3.
Jennifer L. Reidy Frank R. ThompsonIII Courtney Amundson Lisa O’Donnell 《Landscape Ecology》2016,31(2):365-382
Context
Golden-cheeked warblers (Setophaga chrysoparia), an endangered wood-warbler, breed exclusively in woodlands co-dominated by Ashe juniper (Juniperus ashei) in central Texas. Their breeding range is becoming increasingly urbanized and habitat loss and fragmentation are a main threat to the species’ viability.Objectives
We investigated the effects of remotely sensed local habitat and landscape attributes on point occupancy and density of warblers in an urban preserve and produced a spatially explicit density map for the preserve using model-supported relationships.Methods
We conducted 1507 point-count surveys during spring 2011–2014 across Balcones Canyonlands Preserve (BCP) to evaluate warbler habitat associations and predict density of males. We used hierarchical Bayesian models to estimate multiple components of detection probability and evaluate covariate effects on detection probability, point occupancy, and density.Results
Point occupancy was positively related to landscape forest cover and local canopy cover; mean occupancy was 0.83. Density was influenced more by local than landscape factors. Density increased with greater amounts of juniper and mixed forest and decreased with more open edge. There was a weak negative relationship between density and landscape urban land cover.Conclusions
Landscape composition and habitat structure were important determinants of warbler occupancy and density, and the large intact patches of juniper and mixed forest on BCP (>2100 ha) supported a high density of warblers. Increasing urbanization and fragmentation in the surrounding landscape will likely result in lower breeding density due to loss of juniper and mixed forest and increasing urban land cover and edge.4.
Context
Eco-environmental effects of urbanization are a focus in landscape ecology.Objective
The influences of population, economic and spatial development during the urbanization process in Beijing City, China on net primary productivity (NPP) were analyzed. The responding mechanism of NPP in different urbanization stages was also examined to develop advice about eco-environmental sustainability of urban development.Methods
Using the Carnegie Ames Stanford Approach model, we estimated NPP. Using linear regression and polynomial regression analysis, we analyzed NPP responses to stages of urbanization.Results
High NPP areas were located in northeast Yanqing, northwest Miyun, northern Huairou and Pinggu. The distribution of NPP generally occurred in the following order from high NPP to low NPP: outer suburbs, inner suburbs, encircled city center, and inner city. Because of the heat island effect in winter, the estimated NPP in the encircled city center and inner city was higher in 2009 than in 2001. There was a negative correlation between NPP and both economic and spatial urbanization, but an increase in population did not necessarily lead to an immediate decrease in NPP. An analysis of NPP dynamics in five kinds of urban development zones showed that urbanization resulted in a lasting and observable loss of NPP over time and space, although there was some promotion of NPP in highly urbanized zones.Conclusion
There are three stages in the response of NPP to urbanization: damage stage, antagonistic stage, and coordination stage. The stage threshold depends on local eco-environmental management and urban planning interventions.5.
Context
The Rainwater Basin region in south-central Nebraska supports a complex network of spatially-isolated wetlands that harbor diverse floral and faunal communities. Since European settlement, many wetlands have been lost from the network, which has increased distances among remaining wetlands. As a result, populations of wildlife species with limited dispersal capabilities may have become isolated and face greater local extinction risks.Objectives
We compared the pre-European settlement and current extent of the Rainwater Basin network to assess the effects of wetland losses on network connectivity for a range of maximum dispersal distances.Methods
We constructed network models for a range of maximum dispersal distances and calculated network metrics to assess changes in network connectivity and the relative importance of individual wetlands in regulating flow.Results
Since European settlement, the number of wetlands in the Rainwater Basin has decreased by?>?90%. The average distance to the nearest neighboring wetland has increased by 150% to ~?1.2 km, and the dispersal distance necessary to travel throughout the whole network has increased from 3.5 to 10.0 km. Last, relative importance of individual wetlands depended on the maximum dispersal distance. Which wetlands to preserve to maintain connectivity might therefore depend on the dispersal capabilities of the species or taxa of interest.Conclusions
To preserve a broad range of biodiversity, conservation efforts should focus on preserving dense clusters of wetlands at fine spatial scales to maintain current levels of network connectivity, and restoring connections between clusters to facilitate long-range dispersal of species with limited dispersal capabilities.6.
Felicia Pereoglou Christopher MacGregor Sam C. Banks Jeff Wood Fred Ford David B. Lindenmayer 《Landscape Ecology》2016,31(2):255-269
Context
Multiple ecological drivers generate spatial patterns in species’ distributions. Changes to natural disturbance regimes can place early successional habitat specialists at an increased risk of extinction by altering landscape patterns of habitat suitability.Objectives
We developed a series of hypotheses to evaluate the effects of landscape structure, fire history, and site-level habitat quality on site occupancy by an early successional specialist, the eastern chestnut mouse (Pseudomys gracilicaudatus).Methods
We obtained eight years of monitoring data from 26 sites in recently burned heathland in southeast Australia. We used generalised linear models to determine which explanatory variables were related to occupancy. We also explored predictability in patterns of small mammal species co-occurrence.Results
Landscape structure (patch area, landscape heterogeneity) was strongly related to site occupancy. Site occupancy was associated with dead shrubs in the understory and rock cover on ground layer, but was not directly influenced by recent or historical fire. Contrary to contemporary ecological theory, we found no predictable species associations in our early successional community.Conclusions
We recommend surveys take account of landscape configuration and proximity to suitable habitat for optimal results. Fire regimes expected to promote eastern chestnut mouse population growth should encourage the retention of critical habitat features rather than be based on temporal rates of successional stages. For management to adequately account for post-disturbance patterns in early successional communities, a species-by-species, multi-scaled approach to research is necessary.7.
Poliana Mendes Kimberly A. With Luciana Signorelli Paulo De MarcoJr. 《Landscape Ecology》2017,32(4):745-762
Context
Species site-occupancy patterns may be influenced by habitat variables at both local and landscape scales. Although local habitat variables influence whether the site is suitable for a given species, the broader landscape context can also influence site occupancy, particularly for species that are sensitive to land-use change.Objectives
To examine the relative importance of local versus landscape variables in explaining site occupancy of eight bat species within the Brazilian Cerrado, a Neotropical savanna that is experiencing widespread habitat loss and fragmentation.Methods
Bats were surveyed within 16 forest patches over two years. We used a multi-model information-theoretic approach, adjusted for species detection bias, to assess whether landscape variables (percent cover and number of patches of natural vegetation within a 2- and 8-km radius of each forest site) or local site variables (canopy cover, understory height, number of trees, and number of lianas) best explained site occupancy in each species.Results
Landscape variables were among the best models (ΔAICc or ΔQAICc < 2) for four species (top-ranked model for black myotis), whereas local variables were among the best for five species (top-ranked model for vampire bats). Neither local nor landscape variables explained site occupancy in two frugivorous species.Conclusion
Species associated with a particular habitat type will not respond similarly to the amount, distribution or relative suitability of that habitat, or even at the same scale. This reinforces the challenge of species distribution modelling, especially in the context of forecasting species’ responses to future land-use or climate-change scenarios.8.
Elizabeth M. Glenn Damon B. Lesmeister Raymond J. Davis Bruce Hollen Anne Poopatanapong 《Landscape Ecology》2017,32(3):563-579
Context
Conservation planning for at-risk species requires understanding of where species are likely to occur, how many individuals are likely to be supported on a given landscape, and the ability to monitor those changes through time.Objectives
We developed a distribution model for northern spotted owls that incorporates both habitat suitability and probability of territory occupancy while accounting for interspecies competition.Methods
We developed range-wide habitat suitability maps for two time periods (1993 and 2012) for northern spotted owls that accounted for regional differences in habitat use and home range size. We used these maps for a long-term demographic monitoring study area to assess habitat change and estimate the number of potential territories based on available habitat for both time periods. We adjusted the number of potential territories using known occupancy rates to estimate owl densities for both time periods. We evaluated our range-wide habitat suitability model using independent survey data.Results
Our range-wide habitat maps predicted areas suitable for territorial spotted owl presence well. On the demographic study area, the amount of habitat declined 19.7% between 1993 and 2012, while our estimate of the habitat-based carrying capacity declined from 150 to 146 territories. Estimated number of occupied territories declined from 94 to 57.Conclusions
Conservation and recovery of at-risk species depends on understanding how habitat changes over time in response to factors such as wildfire, climate change, biological invasions, and interspecies competition, and how these changes influence species distribution. We demonstrate a model-based approach that provides an effective planning tool.9.
Xyomara Carretero-Pinzón Thomas R. Defler Clive A. McAlpine Jonathan R. Rhodes 《Landscape Ecology》2017,32(4):883-896
Context
Primates are an important component of biodiversity in tropical regions. However, many studies on the effects of habitat change on primates ignore the relative influence of landscape composition and configuration.Objectives
This study addresses the question: how important are landscape-scale forest area and composition relative to patch-scale (1–1080 ha) and site-scale (transect of 1 km) habitat variables for the occupancy and abundance of four primate species in the Colombian Llanos.Methods
Using a randomly stratified survey design, 81 fragments were surveyed for primate occupancy and abundance. We used zero-inflated models to test the relative influence of landscape-scale, patch-scale and site-scale variables on occupancy and abundance for each species. A 95% confidence set of models was constructed using the cumulative Akaike weight for each model and the relative importance of each set of variables calculated for each primate species.Results
Occupancy was determined by a combination of site-scale, patch-scale and landscape-scale variables but this varied substantially among the primate species.Conclusion
Our study highlights the importance of managing primates at a range of scales that considers the relative importance of site-, patch- and landscape-scale variables.10.
Context
North American grassland songbird populations have declined significantly due to habitat loss and fragmentation. Understanding the influence of the surrounding landscape on prairie fragment occupancy is vital for predicting the fate of grassland birds in these heavily altered landscapes.Objectives
We examined the relative importance of local and landscape variables on grassland bird occupancy of prairie fragments using a focal-patch study. We also investigated the spatial scale at which landscape variables were most influential.Methods
We surveyed birds on 29 unplowed prairie fragments in western Minnesota and eastern North and South Dakota. We quantified local habitat on the fragment using vegetation surveys and aerial photographs and the landscape surrounding the fragment out to 4 km using aerial photographs. We analyzed occupancy using multi-model approaches applied to multiple logistic regression.Results
Of 38 species encountered, nine were neither too rare nor too abundant to be analyzed. Predictors of patch occupancy were unique for each bird species, yet general patterns emerged. For eight species, landscape variables were more important than local variables. Mostly, those landscape variables measured configuration (e.g., edge density) and not composition (e.g., percent cover of a particular matrix element). Landscape effects were mostly from variables measured at the greatest extents from the prairie fragment.Conclusions
Using a focal-patch study design we demonstrated the importance of the surrounding landscape, often out to 4 km from the fragment edge, on prairie occupancy by grassland birds. Effective management of grassland songbirds will require attention to the landscape context of prairie fragments.11.
Context
Habitat loss and fragmentation may alter habitat occupancy patterns, for example through a reduction in regional abundance or in functional connectivity, which in turn may reduce the number of dispersers or their ability to prospect for territories. Yet, the relationship between landscape structure and habitat niche remains poorly known.Objectives
We hypothesized that changes in landscape structure associated with habitat loss and fragmentation will reduce the habitat niche breadth of forest birds, either through a reduction in density-dependent spillover from optimal habitat or by impeding the colonization of patches.Methods
We surveyed forest birds with point counts in eastern Ontario, Canada, and analyzed their response to loss and fragmentation of mature woodland. We selected 62 landscapes varying in both forest cover (15–45%) and its degree of fragmentation, and classified them into two categories (high versus low levels of loss and fragmentation). We determined the habitat niche breadth of 12 focal species as a function of 8 habitat structure variables for each landscape category.Results
Habitat niche breadth was narrower in landscapes with high versus low levels of loss and fragmentation of forest cover. The relative occupancy of marginal habitat appeared to drive this relationship. Species sensitivity to mature forest cover had no apparent influence on relative niche breadth.Conclusions
Regional abundance and, in turn, density-dependent spillover into suboptimal habitat appeared to be determinants of habitat niche breadth. For a given proportion of forest cover, fragmentation also appeared to alter habitat use, which could exacerbate its other negative effects unless functional connectivity is high enough to allow individuals to saturate optimal habitat.12.
Anantha M. Prasad Louis R. Iverson Stephen N. Matthews Matthew P. Peters 《Landscape Ecology》2016,31(9):2187-2204
Context
No single model can capture the complex species range dynamics under changing climates—hence the need for a combination approach that addresses management concerns.Objective
A multistage approach is illustrated to manage forested landscapes under climate change. We combine a tree species habitat model—DISTRIB II, a species colonization model—SHIFT, and knowledge-based scoring system—MODFACs, to illustrate a decision support framework.Methods
Using shortleaf pine (Pinus echinata) and sugar maple (Acer saccharum) as examples, we project suitable habitats under two future climate change scenarios (harsh, Hadley RCP8.5 and mild CCSM RCP4.5 at ~2100) at a resolution of 10 km and assess the colonization likelihood of the projected suitable habitats at a 1 km resolution; and score biological and disturbance factors for interpreting modeled outcomes.Results
Shortleaf pine shows increased habitat northward by 2100, especially under the harsh scenario of climate change, and with higher possibility of natural migration confined to a narrow region close to the current species range boundary. Sugar maple shows decreased habitat and has negligible possibility of migration within the US due to a large portion of its range being north of the US border. Combination of suitable habitats with colonization likelihoods also allows for identification of potential locations appropriate for assisted migration, should that be deemed feasible.Conclusion
The combination of these multiple components using diverse approaches leads to tools and products that may help managers make management decisions in the face of a changing climate.13.
Context
The history of the landscape directly affects biotic assemblages, resulting in time lags in species response to disturbances. In highly fragmented environments, this phenomenon often causes extinction debts. However, few studies have been carried out in urban settings.Objectives
To determine if there are time lags in the response of temperate natural grasslands to urbanization. Does it differ for indigenous species and for species indicative of disturbance and between woody and open grasslands? Do these time lags change over time? What are the potential landscape factors driving these changes? What are the corresponding vegetation changes?Methods
In 1995 and 2012 vegetation sampling was carried out in 43 urban grassland sites. We calculated six urbanization and landscape measures in a 500 m buffer area surrounding each site for 1938, 1961, 1970, 1994, 1999, 2006, and 2010. We used generalized linear models and model selection to determine which time period best predicted the contemporary species richness patterns.Results
Woody grasslands showed time lags of 20–40 years. Contemporary open grassland communities were, generally, associated with more contemporary landscapes. Altitude and road network density of natural areas were the most frequent predictors of species richness. The importance of the predictors changed between the different models. Species richness, specifically, indigenous herbaceous species, declined from 1995 to 2012.Conclusions
The history of urbanization affects contemporary urban vegetation assemblages. This indicates potential extinction debts, which have important consequences for biodiversity conservation planning and sustainable future scenarios.14.
Suresh Andrew Sethi Jesse R. O’Hanley Jonathon Gerken Joshua Ashline Catherine Bradley 《Landscape Ecology》2017,32(12):2327-2336
Context
Efficient restoration of longitudinal river connectivity relies on barrier mitigation prioritization tools that incorporate stream network spatial structure to maximize ecological benefits given limited resources. Typically, ecological benefits of barrier mitigation are measured using proxies such as the amount of accessible riverine habitat.Objectives
We developed an optimization approach for barrier mitigation planning which directly incorporates the ecology of managed taxa, and applied it to an urbanizing salmon-bearing watershed in Alaska.Methods
A novel river connectivity metric that exploits information on the distribution and movement of managed taxon was embedded into a barrier prioritization framework to identify optimal mitigation actions given limited restoration budgets. The value of ecological information on managed taxa was estimated by comparing costs to achieve restoration targets across alternative barrier prioritization approaches.Results
Barrier mitigation solutions informed by life history information outperformed those using only river connectivity proxies, demonstrating high value of ecological information for watershed restoration. In our study area, information on salmon ecology was typically valued at 0.8–1.2 M USD in costs savings to achieve a given benefit level relative to solutions derived only from stream network information, equating to 16–28% of the restoration budget.Conclusions
Investing in ecological studies may achieve win–win outcomes of improved understanding of aquatic ecology and greater watershed restoration efficiency.15.
16.
Christopher B. Edge Marie-Josée Fortin Donald A. Jackson David Lawrie Les Stanfield Namrata Shrestha 《Landscape Ecology》2017,32(3):647-662
Context
The cumulative impact of broad scale environmental change includes altered land-cover and fragmentation. Both altered land-cover and fragmentation have a negative effect on species diversity, but the scale they act on may differ because land-cover alters environmental characteristics, whereas fragmentation alters movement among sites.Objectives
We evaluated the scale specific effects of land-cover, fragmentation, and habitat size on alpha and beta diversity (total, turnover, and nestedness).Methods
Stream fish communities were sampled across five urbanizing watersheds. Generalized mixed linear models were used to test how diversity (alpha and beta) is affected by land-cover, connectivity, and habitat size. Indices of land-cover were calculated from correspondence analyses on land-cover data, fragmentation was estimated with the dendritic connectivity index, and habitat size was calculated as the length of the stream segment (alpha diversity) or the length of the stream network (beta diversity).Results
Alpha diversity was most strongly related to land-cover variables associated with urban development and agriculture (negative relationship with urbanization). Whereas, beta diversity was most strongly influenced by habitat size (positive relationship) and fragmentation (positive relationship). Turnover was positively correlated with fragmentation and habitat size, whereas species loss was negatively correlated with habitat size.Conclusions
Land-cover has a larger effect on alpha diversity because it alters the environmental conditions at a site, whereas fragmentation has a larger effect on beta diversity because it affects the movement of individuals among sites. Assessing the cumulative impact of environmental change requires a multiscale approach that simultaneously considers alpha and beta diversity.17.
P.-A. Herrault L. Larrieu S. Cordier U. Gimmi T. Lachat A. Ouin J.-P. Sarthou D. Sheeren 《Landscape Ecology》2016,31(4):877-893
Context
Hoverflies are often used as bio-indicators for ecosystem conservation, but only few studies have actually investigated the key factors explaining their richness in woodlands.Objectives
In a fragmented landscape in southwest France, we investigated the joint effects of woodland area, structural heterogeneity, connectivity and history on the species richness of forest-specialist hoverflies, and whether there was a time lag in the response of hoverflies to habitat changes, and tested the effect of spatiotemporal changes.Methods
Current species richness was sampled in 48 woodlands using 99 Malaise traps. Structural variables were derived from a rapid habitat assessment protocol. Old maps and aerial photographs were used to extract past and present spatial patterns of the woodlands since 1850. Relationships between species richness and explanatory variables were explored using generalized linear models.Results
We show that current habitat area, connectivity, historical continuity and the average density of tree-microhabitats explained 35 % of variation in species richness. Species richness was affected differently by changes in patch area between 1979 and 2010, depending on woodland connectivity. In isolated woodlands, extinction debt and colonization credit were revealed, showing that even several decades are not sufficient for hoverflies to adapt to landscape-scale habitat conditions.Conclusions
These findings emphasise the importance of maintaining connectedness between woodlands, which facilitates the dispersion in a changing landscape. Our results also highlight the benefits of using a change-oriented approach to explain the current distribution patterns of species, especially when several spatial processes act jointly.18.
Context
In agricultural landscapes, riparian forests are used as a management tool to protect stream ecosystems from agricultural activities. However, the ability of managers to target stream protection actions is limited by incomplete knowledge of scale-specific effects of agriculture in riparian corridor and catchment areas.Objectives
We evaluated scale-specific effects of agricultural cover in riparian corridor and catchment areas on stream benthic macroinvertebrate (BMI) communities to develop cover targets for agricultural landscapes.Methods
Sixty-eight streams assigned to three experimental treatments (Forested Riparian, Agricultural Riparian, Agricultural Catchment) were sampled for BMIs. Ordination and segmented regression were used to assess impacts of agriculture on BMI communities and detect thresholds for BMI community metrics.Results
BMI communities were not associated with catchment agricultural cover where the riparian corridor was forested, but were associated with variation in catchment agriculture where riparian forests had been converted to agriculture. Trait-based metrics showed threshold responses at greater than 70% agricultural cover in the catchment. Increasing agriculture in the riparian corridor was associated with less diverse and more tolerant BMI communities. Eight metrics exhibited threshold responses ranging from 45 to 75% agriculture in the riparian corridor.Conclusions
Riparian forest effectively buffered streams from agricultural activity even where catchment agriculture exceeds 80%. We recommend managers prioritize protection of forested riparian corridors and that restore riparian corridors where agricultural cover is near identified thresholds be a secondary priority. Adoption of catchment management actions should be effective where the riparian corridor has been converted to agriculture.19.
Context
Playa wetlands are the primary habitat for numerous wetland-dependent species in the Southern Great Plains of North America. Plant and wildlife populations that inhabit these wetlands are reciprocally linked through the dispersal of individuals, propagules and ultimately genes among local populations.Objective
To develop and implement a framework using network models for conceptualizing, representing and analyzing potential biological flows among 48,981 spatially discrete playa wetlands in the Southern Great Plains.Methods
We examined changes in connectivity patterns and assessed the relative importance of wetlands to maintaining these patterns by targeting wetlands for removal based on network centrality metrics weighted by estimates of habitat quality and probability of inundation.Results
We identified several distinct, broad-scale sub networks and phase transitions among playa wetlands in the Southern Plains. In particular, for organisms that can disperse >2 km a dense and expansive wetland sub network emerges in the Southern High Plains. This network was characterized by localized, densely connected wetland clusters at link distances (h) >2 km but <5 km and was most sensitive to changes in wetland availability (p) and configuration when h = 4 km, and p = 0.2–0.4. It transitioned to a single, large connected wetland system at broader spatial scales even when the proportion of inundated wetland was relatively low (p = 0.2).Conclusions
Our findings suggest that redundancy in the potential for broad and fine-scale movements insulates this system from damage and facilitates system-wide connectivity among populations with different dispersal capacities.20.
Altered functional connectivity and genetic diversity of a threatened salamander in an agroecosystem
John A. Crawford William E. Peterman Andrew R. Kuhns Lori S. Eggert 《Landscape Ecology》2016,31(10):2231-2244