Bees are a functionally important and economically valuable group, but are threatened by land‐use conversion and intensification. Such pressures are not expected to affect all species identically; ...rather, they are likely to be mediated by the species' ecological traits. Understanding which types of species are most vulnerable under which land uses is an important step towards effective conservation planning. We collated occurrence and abundance data for 257 bee species at 1584 European sites from surveys reported in 30 published papers (70 056 records) and combined them with species‐level ecological trait data. We used mixed‐effects models to assess the importance of land use (land‐use class, agricultural use‐intensity and a remotely‐sensed measure of vegetation), traits and trait × land‐use interactions, in explaining species occurrence and abundance. Species' sensitivity to land use was most strongly influenced by flight season duration and foraging range, but also by niche breadth, reproductive strategy and phenology, with effects that differed among cropland, pastoral and urban habitats. Synthesis and applications. Rather than targeting particular species or settings, conservation actions may be more effective if focused on mitigating situations where species' traits strongly and negatively interact with land‐use pressures. We find evidence that low‐intensity agriculture can maintain relatively diverse bee communities; in more intensive settings, added floral resources may be beneficial, but will require careful placement with respect to foraging ranges of smaller bee species. Protection of semi‐natural habitats is essential, however; in particular, conversion to urban environments could have severe effects on bee diversity and pollination services. Our results highlight the importance of exploring how ecological traits mediate species responses to human impacts, but further research is needed to enhance the predictive ability of such analyses.
It is increasingly being recognized that land use and land cover changes driven by anthropogenic pressures are impacting terrestrial and aquatic ecosystems and their services, human society, and ...human livelihoods and well-being. This Special Issue contains 12 original papers covering various issues related to land use and land use changes in various parts of the world (see references), with the purpose of providing a forum to exchange ideas and progress in related areas. Research topics include land use targets, dynamic modelling and mapping using satellite images, pressures from energy production, deforestation, impacts on ecosystem services, aboveground biomass evaluation, and investigations on libraries of legends and classification systems.
•Land-use changes and land polices evolution occurred over different periods in China were analyzed.•Land-use changes were linked closely to shifts in land policies and socio-economic development in ...China.•Deep-seated issues of unsustainable land policies in the process of China’s urbanization have been pondered.•Land policies reform for sustainable management and protection land should be implemented.
Ensuring food security and sustainable development in China has been threatened by the dilemma of the rapidly growing consumption of the country’s land resources. Research on the linkage between land-use changes and land policies in the process of industrialization and urbanization has received increased attention in recent years. The present study was conducted to analyze the undergoing dynamics for Chinese land policies and land-use changes based on reliable land-use data and to develop a thorough understanding of the historical drivers and pathways of land-use changes and China’s deep-seated land issues, as well as the social, political and economic factors involved. The results showed that land-use changes were linked closely to shifts in government land policies and socio-economic development in China. The evolution of land policies in China was the result of a path-dependent process, which included the reform of land use system, the economic development environment as well as a policy-making process that responded to short-term land development. The results also indicated that there have been considerable achievements regarding the land use system and land management in China. However, Chinese economic growth overly depended on investments as well as land finance, which were uncoordinated and unsustainable. The changes in land use were also the outcomes of the land policy failure. There is still a pressing need to reform land policies for more efficient and effective utilization of limited land resources; develop a trade-off and synergy among urban development, agricultural production and ecosystem preservation; differentiate land-use policies; allocate market-oriented land resource; and establish a national macro-control mechanism in collaboration with a coordinated land-use policy and basic legislation.
For biodiversity protection to play a persuasive role in land-use planning, conservationists must be able to offer objective systems for ranking which natural areas to protect or convert. ...Representing biodiversity in spatially explicit indices is challenging because it entails numerous judgments regarding what variables to measure, how to measure them, and how to combine them. Surprisingly few studies have explored this variation. Here, we explore how this variation affects which areas are selected for agricultural conversion by a land-use prioritization model designed to reduce the biodiversity losses associated with agricultural expansion in Zambia. We first explore the similarity between model recommendations generated by three recently published composite indices and a commonly used rarity-weighted species richness metric. We then explore four underlying sources of ecological and methodological variation within these and other approaches, including different terrestrial vertebrate taxonomic groups, different species-richness metrics, different mathematical methods for combining layers, and different spatial resolutions of inputs. The results generated using different biodiversity approaches show very low spatial agreement regarding which areas to convert to agriculture. There is little overlap in areas identified for conversion using previously published indices (mean Jaccard similarity, Jw
, between 0.3 and 3.7%), different taxonomic groups (5.0% < mean Jw
< 13.5%), or different measures of species richness (15.6% < mean Jw
< 33.7%). Even with shared conservation goals, different methods for combining layers and different input spatial resolutions still produce meaningful, though smaller, differences among areas selected for conversion (40.9% < mean Jw
< 67.5%). The choice of taxonomic group had the largest effect on conservation priorities, followed by the choice of species richness metric, the choice of combination method, and finally the choice of spatial resolution. These disagreements highlight the challenge of objectively representing biodiversity in land-use planning tools, and present a credibility challenge for conservation scientists seeking to inform policy making. Our results suggest an urgent need for a more consistent and transparent framework for designing the biodiversity indices used in land-use planning, which we propose here.
Land‐use change is considered the greatest threat to nature, having caused worldwide declines in the abundance, diversity, and health of species and ecosystems. Despite increasing research on this ...global change driver, there are still challenges to forming an effective synthesis. The estimated impact of land‐use change on biodiversity can depend on location, research methods, and taxonomic focus, with recent global meta‐analyses reaching disparate conclusions. Here, we critically appraise this research body and our ability to reach a reliable consensus. We employ named entity recognition to analyze more than 4000 s, alongside full reading of 100 randomly selected papers. We highlight the broad range of study designs and methodologies used; the most common being local space‐for‐time comparisons that classify land use in situ. Species metrics including abundance, distribution, and diversity were measured more frequently than complex responses such as demography, vital rates, and behavior. We identified taxonomic biases, with vertebrates well represented while detritivores were largely missing. Omitting this group may hinder our understanding of how land‐use change affects ecosystem feedback. Research was heavily biased toward temperate forested biomes in North America and Europe, with warmer regions being acutely underrepresented despite offering potential insights into the future effects of land‐use change under novel climates. Various land‐use histories were covered, although more research in understudied regions including Africa and the Middle East is required to capture regional differences in the form of current and historical land‐use practices. Failure to address these challenges will impede our global understanding of land‐use change impacts on biodiversity, limit the reliability of future projections and have repercussions for the conservation of threatened species. Beyond identifying literature biases, we highlight the research priorities and data gaps that need urgent attention and offer perspectives on how to move forward.
In this review, we critically appraise the literature body dealing with the effect of land‐use change on biodiversity. Strong geographic and taxonomic biases, coupled with inconsistent research methods, can obscure regional differences in the intensity of land‐use impacts and hamper our understanding of ecosystem feedback and interactions with other global change drivers. We offer perspectives on the research priorities needed to tackle these challenges and move this field forwards.
•Landsystem science produced many empirical results but lacks progress in theory.•We review theories on causes of changes in land use extent and intensity.•We synthesize middle-range theories of ...systemic land system processes.•Theories of land-use spillovers (land sparing and rebound effects with intensification, leakage).•Theories of land-use transitions (structural non-linear changes, including forest transition).
Changes in land systems generate many sustainability challenges. Identifying more sustainable land-use alternatives requires solid theoretical foundations on the causes of land-use/cover changes. Land system science is a maturing field that has produced a wealth of methodological innovations and empirical observations on land-cover and land-use change, from patterns and processes to causes. We take stock of this knowledge by reviewing and synthesizing the theories that explain the causal mechanisms of land-use change, including systemic linkages between distant land-use changes, with a focus on agriculture and forestry processes. We first review theories explaining changes in land-use extent, such as agricultural expansion, deforestation, frontier development, and land abandonment, and changes in land-use intensity, such as agricultural intensification and disintensification. We then synthesize theories of higher-level land system change processes, focusing on: (i) land-use spillovers, including land sparing and rebound effects with intensification, leakage, indirect land-use change, and land-use displacement, and (ii) land-use transitions, defined as structural non-linear changes in land systems, including forest transitions. Theories focusing on the causes of land system changes span theoretically and epistemologically disparate knowledge domains and build from deductive, abductive, and inductive approaches. A grand, integrated theory of land system change remains elusive. Yet, we show that middle-range theories – defined here as contextual generalizations that describe chains of causal mechanisms explaining a well-bounded range of phenomena, as well as the conditions that trigger, enable, or prevent these causal chains –, provide a path towards generalized knowledge of land systems. This knowledge can support progress towards sustainable social-ecological systems.
This themed issue on Land Use Sustainability in China builds on the papers presented at an internaitonal conference (Pre-International Geographical Union 2016 Conference) on “Land Use and Rural ...Sustainability”, convened by the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences in Xi'an, China on August 17–20, 2016. The conference set out to review the impacts of the transformation of human socio-economic activities on land-use change and associated policy making from both a Chinese and a global perspective. The contributions to this themed issue provide conceptual-theoretical and empirical studies on the topic, covering five themes: key issues of land use and sustainability, urbanization and farmland protection, rural transforamtion and reconstruction, urban-rural interaction in a changing society, and land resources engineering and land use policy. China has undergoneintense socio-economic transformations during recent decades which has affected all sectors of the country’s economy. The rapid urbanization has seriously affected rural areas, leading to the intensification of “rural disease” issues and farmland losses, and the implementation of rural revitalization in China is imperative. In view of this, the papers make a compelling call for more systematic research on land use sustainability and emphasize the challenges for futher research on land use and rural revitalization in China.
Urban land use information is essential for a variety of urban-related applications such as urban planning and regional administration. The extraction of urban land use from very fine spatial ...resolution (VFSR) remotely sensed imagery has, therefore, drawn much attention in the remote sensing community. Nevertheless, classifying urban land use from VFSR images remains a challenging task, due to the extreme difficulties in differentiating complex spatial patterns to derive high-level semantic labels. Deep convolutional neural networks (CNNs) offer great potential to extract high-level spatial features, thanks to its hierarchical nature with multiple levels of abstraction. However, blurred object boundaries and geometric distortion, as well as huge computational redundancy, severely restrict the potential application of CNN for the classification of urban land use. In this paper, a novel object-based convolutional neural network (OCNN) is proposed for urban land use classification using VFSR images. Rather than Pixel-wise convolutional processes, the OCNN relies on segmented objects as its functional units, and CNN networks are used to analyse and label objects such as to partition within-object and between-object variation. Two CNN networks with different model structures and window sizes are developed to predict linearly shaped objects (e.g. Highway, Canal) and general (other non-linearly shaped) objects. Then a rule-based decision fusion is performed to integrate the class-specific classification results. The effectiveness of the proposed OCNN method was tested on aerial photography of two large urban scenes in Southampton and Manchester in Great Britain. The OCNN combined with large and small window sizes achieved excellent classification accuracy and computational efficiency, consistently outperforming its sub-modules, as well as other benchmark comparators, including the Pixel-wise CNN, contextual-based MRF and object-based OBIA-SVM methods. The proposed method provides the first object-based CNN framework to effectively and efficiently address the complicated problem of urban land use classification from VFSR images.
•Object-based CNN (OCNN) were proposed for complex urban land use classification.•The within-object and between-object information were used jointly.•The convolutional position of OCNN were derived by geometry and spatial anisotropy.•High classification accuracy and computational efficiency were achieved.•The OCNN demonstrates great generalisation capability for different applications.
Questions
Past agricultural land use and forest management have shaped and influenced the understorey composition in European forests for centuries. We investigated whether understorey vegetation ...assemblages are affected by (a) legacies from a historical infield/outland agricultural system (i.e., a system with nutrient‐enriched vs nutrient‐depleted areas), (b) recent management intensity (i.e., thinning/felling activities), and (c) the interaction of recent management and potential legacies.
Location
Oak forests in Skåne, south Sweden.
Methods
We use three vegetation surveys (1983, 1993/94 and 2014) and notes on management and land‐use history, available for 62 permanent 500 m² plots. We conducted linear mixed effect modelling to detect both main and interactive effects of past land use and recent management on understorey diversity measures and vegetation indicator values for light and fertility. We combined nonmetric multidimensional scaling with permutational multivariate analysis of variance and indicator species analysis to detect compositional differences caused by past land use and/or recent management.
Results
Understorey diversity was mainly affected by management activities, but the former infield/outland agricultural system was an important determinant of understorey composition. Understorey composition of former infields reflected higher nutrient availability and lower light availability compared to former outland. Past land use and recent management had interactive effects on light‐related understorey variables: for the less intensively managed plots, the outland plots contained more light‐demanding species than the infield plots, while for the more intensively managed plots, the light‐demanding signature of the understorey was similar for infield and outland plots.
Conclusions
Different intensities of past land use as well as recent forest management influenced the composition of the forest understorey, and interactions were present. Therefore, careful consideration of both the long‐term land‐use history and the more recent disturbances due to forest management are necessary when making future predictions of understorey composition and diversity.
Past agricultural land use and forest management have shaped and influenced the understorey of European forests for centuries. We found that, in South Sweden, recent management activities affect understorey diversity, while legacies from a historical infield/outfield agricultural use affect understorey composition. Additionally, recent management intensity and past land use showed interactive effects on light‐related understorey traits.
Land-use planning influences economic performance as it can intervene with location-specific and heterogeneous production externalities. This paper examines the impacts of heterogeneous externalities ...on local employment growth using a panel model framework with block-level land-use data inventory for Chicago. Cross-industry spillovers provide positive impacts on growth, but the mechanisms behind them differ across sectors and spatial scales. Improved understanding of heterogeneity in agglomeration economies can better support plan-making and urban economic performance. The results show significant and positive influence of cross-industry spillovers, a missing consideration in existing planning processes.
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