Agricultural Land Use Intensity Research Articles

Epilithon δ15N signatures indicate the origins of nitrogen loading and its seasonal dynamics in a volcanic Lake

The intensification of agricultural land use and urbanisation has increased nutrient loads in aquatic ecosystems. Nitrogen loads can alter ecosystem structure and functioning, resulting in increased algal productivity, algal blooms and eutrophication. The principal aim of the present paper is to extend the use of epilithic δ15N signatures to a lake ecosystem in order to evaluate the potential impact of anthropogenic nitrogen discharges (organic and inorganic) that can also reach coastal waters.Epilithic associations were collected from volcanic rocks in different seasons in shallow water along the entire perimeter of Lake Bracciano and analysed for their nitrogen stable isotope signatures. Furthermore, some stones were moved from an unpolluted site to a polluted one in order to verify the effect on the nitrogen signature of the epilithic association. The epilithon’s δ15N signatures provided strong evidence of the space-time variability of N inputs. The differing quality of nitrogen loads was reflected in high isotopic variation within the lake, especially at the beginning of summer (1.7‰≤δ15N≤13.3‰), while in winter, when anthropogenic pressure was lowest, the δ15N signature variation was less accentuated (3.1‰≤δ15N≤7.6‰). At all sampling times, spatial variability was found to be related to the various human activities along the lake shore (especially tourism and agriculture), while seasonal variation at all sampling sites was related to the intensity of anthropogenic pressures (higher in summer and lower in winter).Our results showed that epilithic algal associations and the physicochemical properties of the water did not influence the δ15N signature, which in contrast was strongly related to the site-specific effect of human activities around the lake. Thus, the distribution of δ15N across space and time can be used to direct nutrient reduction strategies in the region and can assist in monitoring the effectiveness of environmental protection measures.

Influence of topography and human activity on apparent in situ <sup>10</sup>Be-derived erosion rates in Yunnan, SW China

Abstract. In order to understand better if and where erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin area = 46.5 km2). Erosion rates range from 12 to 209 mm kyr−1 with an area-weighted mean of 117 ± 49 mm kyr−1 (1 standard deviation) and median of 74 mm kyr−1. We observed a decrease in the relative influence of human activity from our steepest and least altered watershed in the north to the most heavily altered landscapes in the south. In the areas of the landscape least disturbed by humans, erosion rates correlate best with measures of topographic steepness. In the most heavily altered landscapes, measures of modern land use correlate with 10Be-estimated erosion rates but topographic steepness parameters cease to correlate with erosion rates. We conclude that, in some small watersheds with high rates and intensity of agricultural land use that we sampled, tillage and resultant erosion has excavated deeply enough into the regolith to deliver subsurface sediment to streams and thus raise apparent in situ 10Be-derived erosion rates by as much as 2.5 times over background rates had the watersheds not been disturbed.

Making the best of both worlds: Can high-resolution agricultural administrative data support the assessment of High Nature Value farmlands across Europe?

Worldwide, the role of farmlands for biodiversity conservation and the delivery of multiple ecosystem services has been widely acknowledged. In the European Union (EU), societal demands to include environmental conservation concerns within the Common Agricultural Policy (CAP) have resulted in the recognition of the importance of maintaining High Nature Value farmlands (HNVf).HNVf constitute complex social-ecological systems, which owe their nature conservation value to the maintenance of specific, mostly low-intensity farming systems, supporting high levels of species and habitats dependent on agricultural practices. Even though HNVf assessment in space and time is essential to evaluate the effectiveness of Rural Development Programmes, the diversity of rural landscapes across EU, the scarcity of data on farming systems, and the lack of common methodological guidelines has hampered the implementation of HNVf mapping and monitoring across Europe. Thus, there is a pressing need to develop and test methodological approaches that may support HNVf assessment across the EU.The Integrated Administration and Control System (IACS) which is mandatory for all EU Member States constitutes a system for the management and control of CAP payments to farmers. Essentially, IACS comprises high-resolution, spatially explicit information on the type and intensity of agricultural land-use. Even though such data exhibits high thematic, spatial and temporal resolution, IACS has seldom been used, due to significant access restrictions. Here, the potential to use IACS data to support the assessment of HNVf was evaluated within the German Federal State of Lower Saxony by implementing a recently developed methodological framework. Sets of indicators known to be essential for identifying potential HNVf and underlying farming systems (expressing landscape structure and composition, farming systems, and crop diversity), were derived from IACS. Spatial patterns of indicators were analyzed at two different scales to delineate the potential distribution of HNVf across Lower Saxony.Results highlighted that most regions in Lower Saxony were characterized by intensive farming practices including high livestock density, high share of intensive crops and low density of linear elements. Only 3% of the Utilized Agricultural Area (UAA) of Lower Saxony potentially constituted HNVf, with the majority of HNVf coinciding with mosaics of arable and/or permanent crops and semi-natural features under less intensive farming practices. Semi-natural grasslands, partially under agri-environment scheme management contracts, covered roughly 1% of the UAA and were mostly intermingled with other farmland habitats in extensively managed agricultural landscapes.In the context of the EU-wide HNVf assessment, IACS constitutes an important source of data, characterized by a high spatial, thematic and temporal resolution of data collected annually. Whilst having the potential for use in HNVf assessment, some challenges remain, especially due to significant access restrictions. Nevertheless, IACS constitutes a powerful tool to evaluate the extent and condition of HNVf across the EU countryside. Making use of IACS data in such a way could provide a stepping-stone towards achieving a more effective balance between the management and control of CAP support payments and the growing societal demands related to the maintenance and enhancement of farmland biodiversity and ecosystem services.

Land suitability analysis for agriculture in the Abbay basin using remote sensing, GIS and AHP techniques

To meet growing population demands for food and other agricultural commodities, agricultural land-use intensification and extensification seems to be increasing in the Abbay (Upper Blue Nile) basin in Ethiopia. However, the amount, location and degree of suitability of the basin for agriculture seem not well studied and/or documented. From global data sources, literature review and field investigation, a number of agricultural land suitability evaluation criteria were identified. These criteria were pre-processed as raster layers on a GIS platform and weights of criteria raster layers in determining suitability were computed using the analytic hierarchy process (AHP). A weighted overlay analysis method was used to compute categories of highly suitable, moderately suitable, marginally suitable and unsuitable lands for agriculture in the basin. It was found out that 53.8 % of the basin’s land coverage was highly suitable for agriculture and 23.2 % was moderately suitable. The marginally suitable and the unsuitable lands were at 11 and 12 % respectively. From the analysis, regions of the basin with high suitability as well as those with higher susceptibility for land degradation and soil erosion were identified.

Phylogenetic and multivariate analyses to determine the effect of agricultural land-use intensification and soil physico-chemical properties on N-cycling microbial communities in drained Mediterranean peaty soils

This study aims to provide first insights on the impact of land-use intensification and soil properties in shaping the composition of N-cycling microbial communities in Mediterranean peaty soils drained for agricultural purposes. An intensively cultivated peaty soil represented by an intensive maize cropping system was compared with an extensive grassland and an agricultural soil left abandoned for 15 years. Clone-library sequencing based on partial amoA and nirK functional genes was used to characterize the composition of ammonia-oxidizer microorganisms and nirK-type bacterial denitrifiers, respectively. The relative roles of land-use intensification and soil physico-chemical properties in community composition shaping were quantified by multivariate analyses. Phylogenetic and multivariate analyses showed that (i) the majority of sequences of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) grouped within the Nitrosotalea and Nitrosospira clusters, respectively; (ii) uncultured denitrifying bacteria were unique to our soil; (iii) land-use intensification shaped the composition of N-cycling communities; (iv) ammonia-oxidizing communities were driven by clay (AOA), bulk density (AOB), and exchangeable calcium (both AOA and AOB); and (v) nirK-type denitrifier bacteria were shaped by silt, ammonium, and exchangeable potassium. Based on the variation partitioning, soil properties were the primary determinants of the AOA and nirK-type denitrifier community composition, while land-use intensification was the major factor shaping the community composition of AOB. These findings improve the knowledge on such vulnerable agrosystems aiming to optimize the management of soil microbes in order to enhance the sustainability of N fertilization.

Impacts of land-use intensification on litter decomposition in western Kenya

Abstract. Tropical forests are faced with a substantial loss of forest cover due to human activities. The various forms of land use influence habitat structure, microclimate, and co-occurring species, with possible effects on ecosystem processes. The forests of western Kenya are the most eastern parts of the Congolian rainforests. Due to the high human population density only few remnants of these rainforests remained. Even protected areas are influenced by human disturbances, with unknown effects on ecosystem processes. Therefore, we quantified the mass loss of leaf litter with and without access of soil invertebrates within forest fragments and sites affected by increasing levels of agricultural land-use intensity in the Kakamega area (western Kenya; 1500 m a.s.l.). Mass loss of litter as an estimate of decomposition rate increased with rainfall during the annual cycle. Furthermore, mass loss increased with the area of forest fragments and decreased with land-use intensification. We found that soil invertebrates had only small effects on mass loss (< 10 %), and this effect decreased with land-use intensification. Our data showed that forest fragmentation has negative effects on litter decomposition. However, the magnitude of this negative effect was not as large as expected.

Spatial impacts of the CAP post-2013 and climate change scenarios on agricultural intensification and environment in Austria

We assess impacts of the latest CAP reform and regional climate change scenarios on agricultural land use intensification and environment in Austria for the period 2025–2040. A spatially explicit integrated assessment based on sequentially coupled models quantifies the impacts at a 1km grid resolution in order to take into account the heterogeneity of agricultural production and environment. The CAP post-2013 will lead to a shift in direct payments from cropland to grassland dominated production regions as well as to a slight decrease in regional producer surpluses in Austria. The economic impact of climate change scenarios depends on the spatial location and the precipitation scenario. The CAP post-2013 will lead to intensification of agricultural land use in favorable cropland and grassland regions as well as to extensification in marginal areas. Regional climate change amplifies land use intensification with increases in crop and forage yields, e.g. in Alpine regions, and land use extensification with declining crop yields, e.g. in eastern cropland regions. Environmental indicators deteriorate at national level in all scenarios. Spatially highly diverging impacts call for more targeted policy measures.

A trait-based framework for stream algal communities.

The use of trait-based approaches to detect effects of land use and climate change on terrestrial plant and aquatic phytoplankton communities is increasing, but such a framework is still needed for benthic stream algae. Here we present a conceptual framework of morphological, physiological, behavioural and life-history traits relating to resource acquisition and resistance to disturbance. We tested this approach by assessing the relationships between multiple anthropogenic stressors and algal traits at 43 stream sites. Our "natural experiment" was conducted along gradients of agricultural land-use intensity (0-95% of the catchment in high-producing pasture) and hydrological alteration (0-92% streamflow reduction resulting from water abstraction for irrigation) as well as related physicochemical variables (total nitrogen concentration and deposited fine sediment). Strategic choice of study sites meant that agricultural intensity and hydrological alteration were uncorrelated. We studied the relationships of seven traits (with 23 trait categories) to our environmental predictor variables using general linear models and an information-theoretic model-selection approach. Life form, nitrogen fixation and spore formation were key traits that showed the strongest relationships with environmental stressors. Overall, FI (farming intensity) exerted stronger effects on algal communities than hydrological alteration. The large-bodied, non-attached, filamentous algae that dominated under high farming intensities have limited dispersal abilities but may cope with unfavourable conditions through the formation of spores. Antagonistic interactions between FI and flow reduction were observed for some trait variables, whereas no interactions occurred for nitrogen concentration and fine sediment. Our conceptual framework was well supported by tests of ten specific hypotheses predicting effects of resource supply and disturbance on algal traits. Our study also shows that investigating a fairly comprehensive set of traits can help shed light on the drivers of algal community composition insituations where multiple stressors are operating. Further, to understand non-linear and non-additive effects of such drivers, communities need to be studied along multiple gradients of natural variation or anthropogenic stressors.

Spatio-temporal analysis of agricultural land-use intensity across the Western Siberian grain belt

The Western Siberian grain belt covers 1millionkm² in Asiatic Russia and is of global importance for agriculture. Massive land-use changes took place in that region after the dissolution of the Soviet Union and the collapse of the state farm system. Decreasing land-use intensity (LUI) in post-Soviet Western Siberia was observed on grassland due to declining livestock whilst on cropland trends of land abandonment reversed in the early 2000s. Recultivation of abandoned cropland as well as increasing fertilizer inputs and narrowing crop rotations led to increasing LUI on cropland during the last two decades. Beyond that general trend, no information is available about spatial distribution and magnitude but a crucial precondition for the development of strategies for sustainable land management. To quantify changes and patterns in LUI, we developed an intensity index that reflects the impacts of land-based agricultural production. Based on subnational yearly statistical data, we calculated two separate input-orientated indices for cropland and grassland, respectively. The indices were applied on two spatial scale: at seven provinces covering the Western Siberian grain belt (Altay Kray, Chelyabinsk, Kurgan, Novosibirsk, Omsk, Sverdlovsk and Tyumen) and at all districts of the central province Tyumen. The spatio-temporal analysis clearly showed opposite trends for the two land-use types: decreasing intensity on grassland (−0.015 LUI units per year) and intensification on cropland (+0.014 LUI units per year). Furthermore, a spatial concentration towards intensity centres occurred during transition from a planned to a market economy. A principal component analysis enabled the individual calculations of both land-use types to be combined and revealed a strong link between biophysical conditions and LUI. The findings clearly showed the need for having a different strategy for future sustainable land management for grassland (predominantly used by livestock of households) and cropland (predominantly managed by large agricultural enterprises), which have to be addressed specifically by the different land users. As all input data are publicly available, the approach described is readily transferable to other regions or countries of the former Soviet Union.

Agricultural land-use intensity and its effects on small mammals in the central region of Argentina

Agriculture intensification is one of the main threats to biodiversity in agricultural systems. The effectiveness of conservation strategies in these systems depends mainly on the compromise between biodiversity conservation and agricultural land use. The aim of this study was to assess the effect of land-use intensity, characteristics of linear habitats (field borders) and their surrounding fields (landscape) on small mammal richness and abundance in agricultural systems of Argentina. In autumn 2009, we performed a removal sampling in 60 traplines located in the field borders of high or low land-use intensity regions. In traplines under high land-use intensity we found seven species while under low land-use intensity we found ten. Characteristic species of grasslands and woodlands such as Monodelphis dimidiata, Thylamys pallidior, Necromys lasiurus and Graomys griseoflavus were only captured in traplines under low land-use intensity. Higher numbers of Calomys musculinus species (habitat generalist) were observed under high land-use intensity while Akodon azarae and Oxymycterus rufus species, known as habitat specialists, were more frequently found in the low land-use intensity region. Border width and height, as well as land use of both sides of the border, were major variables for explaining small mammal abundances. Our results suggest that conservation of wide field borders with characteristics similar to those of natural habitats would be crucial for sustainable management of Pampean agricultural systems which hold high richness and abundance of small mammal species.

Historical TOC concentration minima during peak sulfur deposition in two Swedish lakes

Abstract. Decadal-scale variations in total organic carbon (TOC) concentration in lake water since AD 1200 in two small lakes in southern Sweden were reconstructed based on visible–near-infrared spectroscopy (VNIRS) of their recent sediment successions. In order to assess the impacts of local land-use changes, regional variations in sulfur, and nitrogen deposition and climate variations on the inferred changes in TOC concentration, the same sediment records were subjected to multi-proxy palaeolimnological analyses. Changes in lake-water pH were inferred from diatom analysis, whereas pollen-based land-use reconstructions (Landscape Reconstruction Algorithm) together with geochemical records provided information on catchment-scale environmental changes, and comparisons were made with available records of climate and population density. Our long-term reconstructions reveal that inferred lake-water TOC concentrations were generally high prior to AD 1900, with additional variability coupled mainly to changes in forest cover and agricultural land-use intensity. The last century showed significant changes, and unusually low TOC concentrations were inferred at AD 1930–1990, followed by a recent increase, largely consistent with monitoring data. Variations in sulfur emissions, with an increase in the early 1900s to a peak around AD 1980 and a subsequent decrease, were identified as an important driver of these dynamics at both sites, while processes related to the introduction of modern forestry and recent increases in precipitation and temperature may have contributed, but the effects differed between the sites. The increase in lake-water TOC concentration from around AD 1980 may therefore reflect a recovery process. Given that the effects of sulfur deposition now subside and that the recovery of lake-water TOC concentrations has reached pre-industrial levels, other forcing mechanisms related to land management and climate change may become the main drivers of TOC concentration changes in boreal lake waters in the future.

Impacts of agricultural land-use dynamics on erosion risks and options for land and water management in Northern Mongolia

In Mongolia, nomadic herders have successfully been grazing livestock for more than a millennium. However, in recent years, concerns have increased that changes in management and higher livestock stocking rates may negatively affect vegetation and increase soil erosion, overland flow and sediment load of rivers. In addition, ambitious agricultural policies increase the intensity of agricultural land use thus enforcing a conversion of grassland to agricultural land which is far more susceptible to erosion. In this study, we tackle the question how recent land-use dynamics influence erosion risks and which implications these require on water resources management. The study was part of a larger research effort, studying implementation options for Integrated Water Resources Management (IWRM); in this paper, specifically impacts of land use and land-use change on water resources are studied. The study has been carried out in the Kharaa river basin (KRB) in Northern Mongolia, in which grazing and agriculture play key roles. As several erosion and run-off-relevant factors such as slope, soil type or land use and land cover are widely varying in the KRB, sub-regions of the catchment have been analysed to identify susceptible combinations of environmental and land management factors. In our study we identified that erosion risks in the sub-catchments under current land use and management calculated with the Revised Universal Soil Loss Equation sum up to approximately 2–4 Mg ha−1 year−1 for steppe and 4–9 Mg ha−1 year−1 for croplands, while erosion rates calculated using 137CS measurements resulted in 2–3 Mg ha−1 year−1 on steppe and 15 Mg ha−1 year−1 on cropland. Erosion risk scenarios indicate that land use change as well as management and climate factors can reduce (−30 %) or aggravate erosion risks up to sevenfold and contribute to additional challenges in water and soil management in the KRB. Strategies have to be developed to limit land conversion and implement soil protection in erosion prone sub-regions. IWRM has the potential to bridge sectorial measures, e.g. in agriculture, rural development or nature protection, but erosion and runoff-related impacts currently are addressed in different institutions, legal frameworks and regulations, which may slow down or hamper efficient measures.

Labile soil organic carbon and nitrogen within a gradient of dryland agricultural land-use intensity in Wyoming, USA

Tillage in dryland winter wheat (Triticum aestivum L.)–summer fallow cropping systems of the central High Plains, USA, has caused significant erosion and loss of soil organic matter (SOM), underscoring the need for more sustainable practices on marginally-productive semiarid lands. Conversion to no-till (NT) wheat–fallow or perennial grass–legume cover, as in the Conservation Reserve Program (CRP), provides viable alternatives to tillage-based wheat–fallow practices. However, the overall impact of transitioning on soil biogeochemistry is not fully understood. Labile SOM pools were determined on soil cores (0–120cm) collected in July 2011 from five unfertilized fields that spanned a gradient in disturbance associated with land-use practices: a more intensively tilled wheat–fallow (‘historic’, HT) than a conventional (CT) wheat–fallow with limited herbicides combined with tillage, NT wheat–fallow that exclusively used herbicides for ≥10years, formerly cultivated HT wheat–fallow planted to grass–legume mixture as in the CRP for 7years, and native prairie (NP) with no history of agricultural disturbance. Significant differences in microbial biomass C (MBC), potentially mineralizable C (PMC) and nitrogen (PMN) were largely confined to the surface soil (0–30cm), following the order NP>CRP>all wheat–fallow systems. When expressed on a per soil organic C (SOC) basis, both MBC and PMC followed the order CRP>NP>all wheat–fallow systems. In contrast, when normalized by total soil N (TN), PMN was higher in HT and CT soils than in other soils (NT, CRP, and NP). MBC and PMC were positively correlated with SOC whereas PMN, soil pH, and electrical conductivity (EC) showed a negative relationship with SOC. These results suggest more efficient conservation of SOM under perennial grass–legume system than NT wheat–fallow rotation. We suggest that cessation of tillage alone may not be sufficient for the recovery of labile-pool SOM degraded through long-term cultivation in the absence of inputs for soil fertility renewal.

English

In the past two decades, population-environment research has focused on the hypothesis that house hold population has significant influence on agricultural land-use patterns and the health of the environment. This study is therefore aimed at providing land use planners in Nigeria with basic data and information that will be useful in identifying the prospects for and constraints to intensive cultivation systems in Obagaji area. The simple random sampling technique, using the table of random digits and availability sampling method were respectively employed to select settlements and farmers for investigations. Structured interview was utilized to generate data for the study. In order to capture the inputs to land in the study area, the level of agricultural land-use intensity was measured, using three surrogates, namely, proportion of farmland cultivated, frequency of cultivation and crop combination level. The study results showed that Obagaji area is a mixed cropping region where semi permanent cultivation with rotational bush fallow system dominates the existing cultivation systems. The characteristic features of agricultural practices in households with low number of family members in the area are: more extensive land-use systems, more of shifting elements than permanent cultivation, only very small proportion of land is under cultivation at any one time and very short cropping period on the field. The reverse is true for households with high number of family members. The direct variation in intensity of agricultural land use with regards to family size in the area is significant. Key words: Obagaji area, agricultural land, family size, farm labour.

The influence of land abandonment on farmland bird communities: a case study from a floodplain landscape in Continental Croatia

The abandonment of less productive agricultural land and the intensification of agricultural land use are the main features of the Common Agricultural Policy (CAP) that Croatia will enforce now as new member of the EU. Due to demographic changes and the economic transition in Croatia resulting from war in the 1990s, substantial tracts of agricultural land were abandoned. We investigated two habitat types in the protected floodplain landscape of Lonjsko polje in the continental part of the country: arable land and pastures. Both habitats were maintained by agricultural management and suffered from partial abandonment. Land abandonment increased the susceptibility to encroachment by the invasive plant species Amorpha fruticosa. Data on bird communities were obtained during the breeding season in 2010 while there were high water levels in the floodplain. Data were collected from 63 points, and a total of 1447 individuals from 70 species were recorded during the study. We found that the bird community structure was primarily related to the presence/abandonment of agricultural land use and the habitat type. Further, we detected that the bird community structure in the same habitat type differed by management intensity. Open habitat specialists were most influenced by land abandonment. However, the conservation value (according to the Species of European Conservation Concern value, SPEC) of grazed pastures and abandoned pastures did not differ significantly, in part because the overgrown pastures with high water levels were found to be suitable for Acrocephalus species. The shift in bird community structure between abandoned and managed arable lands were smaller than those detected in the pastoral communities. Because land abandonment is a widespread phenomenon in Croatia, we emphasize the urgent need for a nationwide monitoring program for farmland birds to register the resulting changes in farmland bird communities and to develop appropriate agri-environment measures to mitigate the process.

Farmers, smelters and caravans: Two thousand years of land use and soil erosion in North Pare, NE Tanzania

Slope deposits in North Pare provide evidence of two millennia of anthropogenically driven land clearance, soil erosion and land degradation. Drawing on deposit stratigraphy, soil magnetic parameters, stable carbon isotope composition and radiocarbon dating, three phases of soil erosion are distinguished characterized by distinct surface processes and increasing levels of agricultural land use.Onset of slope deposit formation in Pare since about 300BC documents soil erosion as an immediate consequence of new land use practices associated with the spread of agriculture and iron working across northern Tanzania. By AD 500, slope deposits extended into valley bottoms and to middle slopes suggesting catchment-wide land clearance and soil erosion. In the 15th century AD, progressive anthropogenic soil erosion had exhausted the topsoil resource and material changes of the slope deposits reflect widespread subsoil erosion. The exposure of subsoils represents an ecological tipping point and triggered the transition to a new morphodynamic framework dominated by runoff-based erosion processes that are recorded as sand lenses and sand layers. The most recent deposits show ongoing accelerated erosion and severe land degradation whilst cessation of sand lens preservation indicates pre-colonial intensification of agricultural land use. Land use changes and socioeconomic transitions associated with the establishment of the Ugweno chiefdom and the 19th-century caravan trade are discussed as possible responses to imperceptible long-term land degradation in Pare.The study demonstrates that anthropogenic soil erosion and not external climatic drivers shaped landscape development in Pare and shows that the identification of environmental thresholds is essential for the assessment of resilience in human-dominated ecosystems.

Correlations in species richness between taxa depend on habitat, scale and landscape context

Biodiversity indicators are assumed to reflect changes in e.g. species richness of multiple taxa, but correlations in species richness between taxa have often been shown to be weak. However, only few studies are based on data allowing for rigorous tests whether strengths of correlations differ between habitat and landscape factors. We compared strengths of correlations between species richness of butterflies, plants and farmland birds between habitats (semi-natural grasslands, forest verges or field boundaries), spatial scales (0.8ha, 25ha and 50ha) and landscapes differing in heterogeneity and regional land-use intensity. Between habitats, the correlation between butterflies and plants was strongest in semi-natural grasslands. Also concerning butterflies and plants, the correlation was weakest at the 0.8ha scale, but no consistent scale-dependent patterns were found between plants and farmland birds. In a regional context, butterfly and plant species richness were consistently positively correlated, whereas when involving farmland birds we found correlations between taxa to be weaker and/or not significant in regions with high agricultural land-use intensity and in homogeneous landscapes. In general, species richness was consistently congruent only between butterflies and plants, whereas correlations involving farmland birds were mainly weak and showed contrasting patterns depending on regional context. Increasing landscape heterogeneity thus increased congruence amongst all studied taxa, but in different contexts and due to different underlying mechanisms. Although plants were involved in most of the significant correlations we cannot recommend a particular taxon as a general diversity indicator.

The impact of urban expansion on agricultural land use intensity in China

China's urbanization has resulted in significant changes in both agricultural land and agricultural land use. However, there is limited understanding about the relationship between the two primary changes occurring to China's agricultural land – the urban expansion on agricultural land and agricultural land use intensity. The goal of this paper is to understand this relationship in China using panel econometric methods. Our results show that urban expansion is associated with a decline in agricultural land use intensity. The area of cultivated land per capita, a measurement about land scarcity, is negatively correlated with agricultural land use intensity. We also find that GDP in the industrial sector negatively affects agricultural land use intensity. GDP per capita and agricultural investments both positively contribute to the intensification of agricultural land use. Our results, together with the links between urbanization, agricultural land, and agricultural production imply that agricultural land expansion is highly likely with continued urban expansion and that pressures on the country's natural land resources will remain high in the future.

Land use changes in the rural–urban fringe: An Israeli case study

The paper analyses the changing pattern of land uses in rural settlements located in the rural–urban fringe and makes a link between the results to socio-economic developments and to changes in the rural policy at the national level. Using historical sequences of land use maps and using geostatistical analysis, we observe changing land use patterns in three Moshav type settlements – the most common type of rural settlement in Israel – in three different rural–urban fringes belts along the coastal area. We identify basic trends of specialisation and intensification of agricultural land use as well as expansion of built up structures for residential and commercial purposes. These trends which are rather similar for all three cases, we argue, reflect economic and social changes in rural settlements in general and in the rural–urban fringe in particular. The evolving patterns in the three Moshavim in the Israeli rural–urban fringe (RUF) can be understood as adjustment measures at the household level to development and changing policies at the macro level, particularly towards the rural sector. There are two major domains of change. First, a transition from dependence on farming to a more diversified economic base suggesting newly shaped interrelationships with the urban space. Second, a new residential development program which has rejuvenated failing and ageing rural settlements. The outcome is a major process of restructuring which affects the economic, social and environmental spheres, and necessitates sensitivity on the part of institutional decision makers towards the complex and diverse realities of relevant actors on the ground, through which all current and future land use policies are mediated. Moreover, being exposed to uncontrolled and often chaotic adjustment measures over the last three decades, it might be necessary to regulate and preserve some of the Moshav's distinct features so it does not to fade into an ‘ordinary suburb’.

The effect of Landsat ETM/ETM + image acquisition dates on the detection of agricultural land abandonment in Eastern Europe

Many terrestrial biomes are experiencing intensifying human land use. However, reductions in the intensity of agricultural land use are also common and can lead to agricultural land abandonment. Agricultural land abandonment has strong environmental and socio-economic consequences, but fine-scale and spatially explicit data on agricultural land abandonment are sparse, particularly in developing countries and countries with transition economies, such as the post-Soviet countries of Eastern Europe. Remote sensing can potentially fill this gap, but the satellite-based detection of fallow fields and shrub encroachment is difficult and requires the collection of multiple images during the growing season. The availability of such multi-seasonal cloud-free image dates is often limited. The goal of our study was to determine how much “missing” Landsat TM/ETM+ images at key times in the growing season affect the accuracy of agricultural land abandonment classification. We selected a study area in temperate Eastern Europe where post-socialist agricultural land abandonment had become widespread and analyzed six near-anniversary cloud-free Landsat images from “Spring”, “Summer” and “Fall” agriculturally defined seasons for a pre-abandonment-time I (1989) and post-abandonment-time II (1999/2000). Using a factorial experiment, we tested how the classification accuracy and spatial patterns of classified abandonment changed over all possible 49 image-date combinations when mapping both “abandoned arable land” and “abandoned managed grassland”. The conditional Kappa of our best overall classification with support vector machines (SVM) was 90% for “abandoned arable land” and 72% for “abandoned managed grassland” when all six images were used for the classification. Classifications with fewer image dates resulted in a substantial decrease of the conditional Kappa (from 93 to 54% for “abandoned arable land” and from to 75 to 50% for “abandoned managed grassland”). We also observed substantial decrease in accurate detection of land abandonment patterns when we compared our best overall classification with the other 48 image date combinations (the Fuzzy Kappa, a measure of spatial similarity, ranged from 25.8 to 76.3% for “abandoned arable land” and from 30.4 to 79.5% for “abandoned managed grassland”). While the accuracy of the different abandonment classes was most sensitive to the number of image dates used for the classification, the seasons captured also mattered, and the importance of specific seasonal image dates varied between the pre- and post-abandonment dates. For “abandoned arable land” it was important to have at least one “Spring” or “Summer” image for pre-abandonment and as many images as possible for post-abandonment, with a “Spring” image again being most important. For “abandoned managed grassland” no specific seasonal image dates yielded statistically significantly more accurate classifications. The factor that influenced the accurate detection of “abandoned managed grassland” was the number of multi-seasonal image dates (the more the better), rather than their exact dates. We also tested whether SVM performed better than the maximum likelihood classifier. SVM outperformed the maximum likelihood classifier only for “abandoned arable land” and only in image-date-rich cases. Our results showed that limited image-date availability in the Landsat record placed substantial limits on the accuracy of agricultural abandonment classifications and accurately detected agricultural land abandonment patterns. Thus, we warn to use agricultural land abandonment maps produced with the sub-optimal image dates with caution, especially when the accurate rates and the patterns of agricultural land abandonment are crucial (e.g., for LULCC models). The abundance of agricultural abandonment in many parts of the world and its strong ecological and socio-economic consequences suggest that better monitoring of abandonment is necessary, and our results illustrated the image dates that were most important to accomplishing this task.