Intensification Of Agricultural Management Research Articles

Agricultural intensity interacts with landscape arrangement in driving ecosystem services

Agricultural intensification has enhanced productivity but also led to enormous ecosystem service and biodiversity losses. Strategic spatial landscape design could counteract this trend, but, the scientific understanding of how ecosystem services respond to agricultural practices on one hand and land use composition and configuration on the other is not complete. This study aims to methodically explore how the effect of landscape layout settings on ecosystem services depends on the intensity of agricultural practices in their surroundings. Using the Netherlands as a case study, we used spatial regression models to analyze how agricultural management intensity affects the relationship between spatial composition and configuration metrics and ecosystem service indicators. We found that the effect of large shares of agricultural land use on species richness, pollination and landscape appreciation was increasingly negative with amplified intensity of agricultural practices. With higher agricultural intensity in the surroundings, the positive effects of well-connected natural vegetation on species richness were impaired. In contrast, the negative effects of high-intensity agriculture on pollination service were be buffered well through high shares of natural grassland vegetation. Water-quality related indicators were less affected by variation in spatial metrics and agricultural intensity. The main interactions between agricultural intensity and the spatial metrics were robust at varying scales. Our analysis suggests that both low- and high-intensity agriculture can have a place in future sustainable agricultural systems, provided they are integrated in the appropriate spatial layout. Explicitly addressing farming practices in connection to local spatial settings can improve both landscape planning and ecosystem service modelling.

Management of U.S. Agricultural Lands Differentially Affects Avian Habitat Connectivity

Despite frequently being implicated in species declines, agricultural lands may nonetheless play an important role in connecting wildlife populations by serving as movement corridors or stopover sites between areas of high-quality habitat. For many North American bird species, agricultural intensification over the past half century has substantially impacted populations, yet recent studies have noted the potential for supporting avian biodiversity on agricultural lands through the promotion of functional connectivity. To support avian conservation efforts on agricultural lands across the United States, we used publicly available data from eBird to quantify and map the effects of agriculture on habitat suitability (using random forest models) and functional connectivity (via circuit theory) for three focal species that have experienced agriculture-linked declines or range contractions in recent decades: Greater Sage-grouse (Centrocercus urophasianus), American Black Duck (Anas rubripes), and Bobolink (Dolichonyx oryzivorus). Our analysis drew on novel, remotely sensed estimates of agricultural management intensity to quantify the effects of management practices on avian habitat and movement, revealing complex, species-specific relationships between agriculture and habitat value for the three focal species. Rangelands and croplands exhibited relatively high connectivity values for Greater Sage-grouse and Bobolink, respectively, mirroring these species’ strong habitat preferences for open sagebrush and cultivated grasslands. By contrast, American Black Duck migratory connectivity was low on all agricultural cover types. Mapping our model results across each species’ geographic range in the U.S. revealed key areas for agricultural management action to preserve high-quality habitat and connectivity, and we link these spatial recommendations to government incentive programs that can be used to increase wildlife-friendly management on U.S. agricultural lands.

Mapping connectivity and conservation opportunity on agricultural lands across the conterminous United States

Depending on management practices, agricultural lands can either pose substantial barriers to species movement or can support landscape connectivity by linking areas of high-quality habitat. Balancing connectivity and sustainable food production on agricultural lands is critical to conservation in the conterminous United States (CONUS) where agriculture makes up close to half of total land area. However, limited guidance exists on where to target conservation resources to maximize benefits for native species and food security. To quantify the potential contribution of agricultural lands to the movement of organisms, we developed a novel method for estimating agricultural management intensity (based on remotely sensed temporal variation in vegetation cover) and incorporated these estimates into a CONUS-wide model of ecological flow connectivity. We combined our connectivity results with data on the productivity, versatility, and resilience of agricultural lands (PVR) to identify conservation opportunities that support both biodiversity and food production. The highest levels of connectivity on agricultural lands occurred on relatively unmodified rangelands and on cropland and pasture surrounded by large amounts of natural land cover. Mapping connectivity and PVR across CONUS revealed 10.2 Mha of agricultural lands (2.7 %) with high value for both connectivity and food production, as well as large amounts of agricultural land (>140 Mha in total) with high value for either cultivation or supporting biodiversity. Drawing on these findings, we provide recommendations on the types of conservation approaches most suitable for a given agricultural system and link these recommendations to specific government incentive programs.

Agricultural management intensity determines the strength of weed seed predation

Agricultural intensification both increases disturbances at the field level and reduces habitat heterogeneity at the landscape level and this can have detrimental effects on biodiversity-driven ecosystem services. A few studies have shown that agricultural intensification can diminish the ecosystem service of weed seed predation, but it is not known to what extent availability of crop and non-crop habitat can provide disturbance refugia for weed seed predators and how those effects cascade to ecosystem service provisioning. Using data from 13 fields in Southern Sweden, we first combined diet preference traits, activity density and metabolic theory, in order to develop a metric that approximates the community strength of seed predation. We then explored how the impact of field management intensity and habitat refugia on seed card predation rates mediated by weed seed availability and the metric of community strength of seed predation. We found that increasing field management intensity directly reduced seed card predation rates and weed seed availability and that reduced weed seed availability in turn impaired the community strength of seed predation. This suggests an indirect mechanism by which field management limits seed predator potential for weed seed predation. We found no evidence that either crop or non-crop refugia can increase seed card predation rates or community strength of seed predation during disturbances in the crop. Consequently, weed seed predation can be promoted by reducing disturbances at the field level, regardless of the availability of disturbance refugia in the landscape. Reduction of field management intensity can directly increase weed seed predation and indirectly seed predator communities’ potential for weed seed predation by increasing weed seed availability. Future research is needed to explore if supporting a diversity of non-competitive weeds to enhance seed availability can improve the suppression of dominant and competitive weed species.

Soil food web structure and function in annual row-crop systems: How can nematode communities infer soil health?

Increased agricultural management intensity is known to degrade soil food web structure and function, however, the impact of 50+ years of contrasting agricultural management practices on soil food webs is largely unknown. The relationship between soil food web structure and sensitive soil health indicators has seldom been quantified in row crop agricultural systems in the Midwest, USA. This study aims to 1) quantify soil food web structure and function in long-term systems that range in tillage intensity and perenniality over the course of a single growing season; and 2) identify the relationship between soil health indicators and soil food web structure. Nematode feeding groups and nematode indices were used to indicate soil food web structure and soil food web function, respectively. Additionally, a suite of soil health indicators including permanganate oxidizable carbon (POXC), β-glucosidase (GLU), and N-Acetyl-β-glucosaminidase (NAG) were measured in two identical long-term experimental trials with contrasting soil types (clay versus silt loam) under two tillage intensities (chisel till (CT) vs. no-till (NT)) combined with two crop rotations (corn-soy (CS) vs. corn-forage-forage (CFF)). All samples were collected in the corn phase of the rotation. Non-metric multidimensional scaling of nematode community assemblage and vector analysis demonstrated that soil food web structure was significantly related to POXC, GLU, and NAG within CFF systems. Nematode families Thornenematidae and Rhabditidae served as indicators of improved and degraded soil food web function, respectively. Our findings indicate that including perennials within a crop rotation fosters a soil food web structure that can enhance carbon and nitrogen cycling in large scale row-crop agriculture. Moreover, this study emphasizes the potential for specific nematode families to serve as indicators of soil food web function, demonstrating that nematodes should be integrated into the soil health framework.

Microbial necromass carbon and nitrogen persistence are decoupled in agricultural grassland soils

Microbial necromass is an important component of soil organic matter, however its persistence and contribution to soil carbon sequestration are poorly quantified. Here, we investigate the interaction of necromass with soil minerals and compare its persistence to that of plant litter in grassland soils under low- and high-management intensity in northwest England. During a 1-year laboratory-based incubation, we find carbon mineralization rates are higher for plant leaf litter than root litter and necromass, but find no significant difference in carbon persistence after 1 year. During a field experiment, approximately two thirds of isotopically-labelled necromass carbon became mineral-associated within 3 days. Mineral-associated carbon declined more rapidly than nitrogen over 8 months, with the persistence of both enhanced under increased management intensity. We suggest that carbon mineralisation rates are decoupled from carbon persistence and that necromass carbon is less persistent than necromass nitrogen, with agricultural management intensity impacting carbon sequestration in grasslands.

Wetlands support higher breeding wader densities than farmed habitats within a nature-rich farming system

ABSTRACT Capsule Wetlands with little or no agricultural activity support higher breeding wader densities than more intensively farmed habitats within a nature-rich farmed landscape. Aims To test whether breeding wader densities differ between habitats likely to receive varying agricultural management intensity, within a nature-rich farmed landscape. Methods Using the island of Sanday as a case study for the wader-rich Orkney archipelago, a whole-island breeding wader survey was used to generate population estimates and test whether breeding densities differed between habitats under varying management intensities. Results The island supported nationally high breeding wader densities, which approach those of high-density areas elsewhere in Europe. Densities of total waders and five out of six species tested varied significantly between habitats. Wetlands subject to no agricultural management or livestock grazing in some land units supported higher densities than more intensively farmed habitats for total waders, Northern Lapwing Vanellus vanellus, Common Snipe Gallinago gallinago and Common Redshank Tringa totanus and second-highest densities for Eurasian Curlew Numenius arquata. Agriculturally unimproved grassland supported the highest densities for many species after wetlands. Agriculturally improved grassland supported consistently low relative breeding densities, and other habitats managed using mechanized farming (lower intensity improved grassland and arable) supported generally low relative densities, apart from for Eurasian Oystercatcher Haematopus ostralegus. Conclusions Describing an entire mixed farming system as nature-rich may mask significant variation in the contribution of different habitats to the maintenance of high nature value. In this system, wetlands that were unmanaged or received low average grazing densities supported disproportionately high breeding wader densities and must be protected to maintain the high densities of most species. The further loss of wetlands, and the move towards intensively managed grassland, is a threat to the maintenance of high breeding wader densities on Orkney and in similar farmed landscapes.

Bioaccumulation and potential ecotoxicological effects of trace metals along a management intensity gradient in volcanic pasturelands

The particularities of volcanic soils raise the need to better understand the link between soil agricultural management intensity and trace metal bioaccumulation. The Azores are a region characterized by volcanic soils, which were changed in different degrees according to the intensity of the agricultural practices. The main objective of this study was to assess the potential ecotoxicological effects of the trace metals present in volcanic pastureland soils along a gradient of management intensity (i.e., semi-natural, permanent and reseeded), using earthworms (Eisenia fetida) as biological indicators. For this purpose earthworms were exposed during 7, 14, 28 and 56 days to soils from the three types of pastures. At each exposure time, we quantified trace element bioaccumulation (As, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Rb, U, V and Zn) and the activities of superoxide dismutase and acetylcholinesterase in earthworm tissues. Overall, the results showed that the type of pastureland management significantly increased the soil contents in trace metals: V, Co, Ni and Zn in semi-natural pasturelands; As, Cd and Hg in reseeded pasturelands; and, Rb and U in both permanent and reseeded pasturelands. The soil physicochemical properties observed in the reseeded pastureland systems (higher electric conductivity values associated with a moderately acid pH value) modulated the metal bioavailability, from soil to biota, leading to a greater Hg bioaccumulation in earthworm tissues. The long-term exposure (56 days) of earthworms to reseeded pastureland soil was associated with adverse biological effects (intensification of AChE activity and decrease of SOD activity), encompassing key processes such as neurotransmission and antioxidant defence mechanisms in resident soil biota (earthworms). This study point towards the increased importance of semi-natural and permanent pastureland management, over the intensive management (reseeded pasturelands), in favour of more sustainable ecosystems.

Ecosystem Services of Kettle Holes in Agricultural Landscapes

Kettle holes are small water bodies of glacial origin which mostly occur in agricultural landscapes. They provide numerous ecosystem services (ES), but their supply may be negatively affected by agricultural management. We conducted a literature review to identify which ES are supplied by kettle holes and to analyze feedbacks with agricultural management. Taking Germany as a test case, we also analyzed how kettle holes are addressed in policy documents and for which ES they are regulated. This was done to identify the societal value officially associated with kettle holes. The literature review found eight ES attributed to kettle holes, of which hydrological cycle and flood control, chemical condition of freshwaters, nursery populations and habitats and biotic remediation of wastes were addressed most often. In contrast, only the provision of habitat service was addressed in German policy documents related to kettle holes. We identified types of agricultural management that negatively affected the supply of ES by kettle holes, in particular artificial drainage, high levels of pesticide and fertilizer application, and management where tillage and erosion result in elevated sediment inputs. Additionally, climate change may lead to an increased drying up of kettle holes. Based on our finding, we conclude that the intensity of agricultural management around kettle holes threatens the supply of all ES while only the service of providing habitats for biodiversity is addressed in German policy regulations. Further regulation is required to induce agricultural management change towards a conservation of all ES supplied by kettle holes.

Agriculture intensification reduces plant taxonomic and functional diversity across European arable systems

Abstract Agricultural intensification is one of the main drivers of species loss worldwide, but there is still a lack of information about its effect on functional diversity of arable weed communities. Using a large‐scale pan European study including 786 fields within 261 farms from eight countries, we analysed differences in the taxonomic and functional diversity of arable weeds assemblages across different levels of agricultural intensification. We estimated weed species frequency in each field, and collected species' traits (vegetative height, SLA and seed mass) from the TRY plant trait database. With this information, we estimated taxonomic (species richness), functional composition (community weighted means) and functional diversity (functional richness, evenness, divergence and redundancy). We used indicators of agricultural management intensity at the individual field scale (e.g. yield, inputs of nitrogen fertilizer and herbicides, frequency of mechanical weed control practices) and at the landscape scale surrounding the field (i.e. number of crop types, mean field size and proportion of arable land cover within a radius of 500 m from the sampling points). The effects of agricultural intensification on species and functional richness at the field scale were stronger than those of intensification at the landscape scale, and we did not observe evidence of interacting effects between the two scales. Overall, assemblages in more intensified areas had fewer species, a higher prevalence of species with ruderal strategies (low stature, high leaf area, light seeds), and lower functional redundancy. Maintaining the diversity of Europe's arable weed communities requires some simple management interventions, for example, reducing the high intensity of field‐level agricultural management across Europe, which could be complemented by interventions that increase landscape complexity. A free Plain Language Summary can be found within the Supporting Information of this article.

Simulation and evaluation of the spatial heterogeneity of shallow-groundwater environmental risk in an urban–rural fringe of megacity: a case study of Shenyang city, northeast China

Shenbei district of Shenyang city, Liaoning province, northeast China is a typical urban–rural (peri-urban) fringe of a megacity that is undergoing rapid urban expansion and the intensification of agricultural management, which threatens the quality of shallow groundwater in the area. This study selects proper indices relevant to vulnerability, stress, function, and adaptability based on the results of groundwater monitoring and the collection and processing of hydrogeological data. Based on the theory of natural disaster risk, an evaluation index system was then established, followed by constructing a groundwater environmental-risk assessment model. Next, the model was used to perform environmental risk grading and spatial pattern assessment on the groundwater based on the statistics and spatial analysis function of ArcGIS. The assessment results were then subjected to a correlation analysis with land use indices and socioeconomic indices, to explore the effects of natural geological conditions, urban expansion and intensive agricultural management on groundwater environment. The results of the study will provide support for land use optimization and water environmental management decision-making during the development and construction of the urban–rural fringe of the area. The results of the study showed that: (1) the spatial distribution of groundwater environmental risk of the Shenbei district is similar to that of groundwater vulnerability. At present, geological conditions are still the main influential factors of groundwater environmental risk in the region; (2) the scale and intensity of urbanization and intensive agricultural management have shown an obvious potential risk to the groundwater environment; (3) the large area paddy fields in the northwest have certain ecological function value, which should be further protected to ensure a win–win situation of agricultural production and environmental safety; (4) it is necessary to put more environmental protection efforts such as ensuring natural vegetation protection, strengthening artificial afforestation, and increasing the number of waste water treatment facilities during the urbanization process, as these measures are significantly effective in maintaining the groundwater quality.

A classification of European agricultural land using an energy-based intensity indicator and detailed crop description

With agricultural areas covering almost half of European land, proper management of agro-ecosystems is key to achieve the European Union’s environmental and climate objectives. This requires spatially explicit methods and indicators. We developed an approach for the classification of agricultural land by combining two main dimensions i) land cover, using detailed geo-spatialized census data covering 63 individual crops; ii) management intensity, measured as the anthropogenic energy required in the primary crop production. As a result we identified 10 main crop systems further classified into 30 ‘crop-management systems’ at a spatial resolution of 5 arcminutes. The resulting maps show the spatial patterns of agricultural management intensity across Europe, both in absolute terms (total energy input per hectare) and relative to the dominant crop system in the spatial unit of analysis. The use of multiple intensity dimensions provides new, more detailed insights on agricultural intensity by which areas that were previously classified as low-medium intensive - some permanent crops systems or irrigated arable land - appear now as highly intensive. An expert-based evaluation was carried out on the intensity maps and corroborated the obtained results. The generated maps can be used to support decision-making in designing more targeted, context-specific agricultural and territorial policies. In particular, findings can be relevant in the context of the Common Agricultural Policy post 2020 and the Biodiversity Strategy towards 2030, both of which will benefit from more detailed spatially explicit information to achieve their stated objectives.

How Do Crop Area and Management Intensity Influence Tropical Lizard Species Diversity?

Crop area (CA) and agricultural management intensity (AMI) are the two main factors associated with agricultural systems that can negatively affect the diversity of animal communities. Despite exis...

Can agricultural intensification help to conserve biodiversity? A scenario study for the African continent

Globally, the production of food, feed, bioenergy, and biomaterials has increased considerably during the past decades. This was achieved by the expansion of agricultural land and the intensification of agricultural management. Due to the conversion of natural ecosystems and the increasing use of pesticides and fertilizers, these processes are recognized as important causes of biodiversity loss. This study focuses on the African continent and analyses the potentials to achieve a stable food provision for a growing population, and at the same time, reduce further losses of biodiversity. These targets are important elements of the UN Agenda 2030. Using the spatially explicit land-use model LandSHIFT, we assessed the effectiveness of different land-sparing and land-sharing strategies to achieve these targets until the year 2030. The simulation results indicate that under the assumptions tested, the land sparing approach yields the most desirable results both, on the continental and the regional level. However, the land sharing/sparing framework in general, and the research presented here only analyse the effect of two factors of many (food production and biodiversity conservation). Hence, this study should not be understood to provide specific management recommendations. Further studies, from the regional to the local level, are required that apply a systems approach to understand and explain the multiple dimensions of sustainable food production on the African continent.

Organic farming at local and landscape scales fosters biological pest control in vineyards.

While organic farming practices, which are often promoted as models of ecological intensification, generally enhance biodiversity, their effects on the delivery of ecosystem services, such as biological pest control, are still unknown. Here, using a multi-scale hierarchical design in southwestern France, we examined the effects of organic farming and seminatural habitats at the local and landscape scales on biological control services of three pests, including weeds and insects, in 42 vineyards. Organic farming at the local and landscape scales was beneficial to the mean and temporal stability of biological control services, while the proportion of seminatural habitats in the landscape reduced the level of biological pest control potential. The effects of organic farming and seminatural habitats across spatial scales varied with the type of prey considered and with time. Egg moth removal rates were higher in fields under organic management compared to conventional management while weed seed removal rates increased with the proportion of organic farming in the landscape. Larval removal rates as well as seed removal rates were always more stable within time in organic fields than in conventional fields. Moreover, independently of farming system type, local variables describing the agricultural management intensity, such as pesticide use or crop productivity, were also found to be important variables explaining levels of biological control services. Pesticide use tended to reduce biological control potential, while crop productivity was associated with contrasting biological control responses depending on the pest type. Our study demonstrates the need to target multiple spatial scales and to consider farming practices, as well as the proportion of seminatural habitats, to design functional landscapes that optimize biological pest control services.

Activity, diversity and function of arbuscular mycorrhizae vary with changes in agricultural management intensity

Many beneficial soil microbes are sensitive to chemical and mechanical disturbances associated with conventional row crop agriculture, including arbuscular mycorrhizal (AM) fungi. AM fungi provide agricultural benefits through multiple mechanisms including increasing crop pathogen resistance, helping with crop nutrient acquisition, and increasing soil carbon storage. Conversion to less intensive row crop agricultural management systems such as biologically-based organic and no-till may reduce the negative effects of conventional management to AM fungi. In this study, AM fungus activity (via glomalin production), spore diversity, community structure, and community stability were surveyed over 20 years in no-till, biologically-based organic, and conventionally managed plots at the W.K. Kellogg Biological Station Long Term Ecological Research Site in Michigan, USA. A complementary greenhouse experiment tested for direct effects of AM fungal inocula from these different agricultural management treatments on growth of corn and wheat plants. Soil glomalin increased in no-till and organic management systems, most likely due to decreases in disturbance associated with tillage and chemical inputs. No-till management slightly increased AM fungus diversity and community stability. AM fungus community structure significantly differed between conventional and no-till treatments, with an indicator species analysis showing that Acaulospora spp. were characteristic of conventional management, while Glomus spp. and Gigaspora spp. were associated with no-till management. AM fungal inocula from organically-managed treatments increased wheat, but not corn, growth. Overall, conversion from long-term conventional row crop agricultural management to no-till or biologically-based organic systems increased soil glomalin, but did not uniformly improve AM fungus diversity or crop plant benefits. In the future, novel agricultural systems combining organic management with conservation tillage may further improve AM fungal benefits to soils and crops.

Turning points of ecological resilience: Geostatistical modelling of landscape change and bird habitat provision

Due to field enlargements and removal of landscape elements, intensification of agricultural management is frequently related to the alteration of the landscape structure and composition of elements, resulting in a decreased ecological capability. This study presents a spatially explicit probabilistic approach to model and analyse the effect of landscape elements removal on landscape connectivity and heterogeneity in a case study in North-Eastern Germany. Simulation of stepwise removal of tree elements as potential landscape changes is applied to assess resulting impacts on the related ecological habitat function for the red-backed shrike (Lanius collurio), a representative farmland bird species. The analysis of variograms' parameters identified a turning point in landscape structure constellation, occurring at a removal of nearly 50% of the tree elements, in correspondence of a 21% reduction in heterogeneity and a 20% reduction in elements connectivity. In terms of habitat provision, the turning point appeared at a shifted level, corresponding to a 50% reduction of connectivity, resulting from a ca. 75% reduction in spatial variability. It is argued that at the turning points the agricultural landscape would reach the limits of its resilience in terms of the habitat function associated to the removed elements. Results, displayed as probability maps, highlight that a high probability of tree elements occurrence is not always coupled with a high probability of habitat provision. The approach offers planners the possibility to identify structural and functional resilience thresholds for the management of multifunctional agricultural landscapes.

Effects of land use and landscape patterns on Orthoptera communities in the Western Siberian forest steppe

Across Western Siberia, land use has changed substantially since the collapse of the Soviet Union in 1991: large cropland areas were abandoned and livestock numbers declined. In recent years these trends have partly been reversed, and an intensification of agricultural management has been observed that is still ongoing. We evaluated the impact of land use, as well as effects of landscape patterns and vegetation structure on Orthoptera communities and discuss them as drivers of community composition, species richness and abundance. We sampled Orthoptera using a box-quadrat on ancient grassland, ex-arable grassland (both including different management types: unmanaged, grazed and mown) and cereal fields. Landscape heterogeneity and composition strongly affected species richness and abundance of Orthoptera. Both were higher in grassland than in cropland, but did not differ significantly between ex-arable and ancient grasslands or different management practices. An Indicator Species Analysis revealed differentiation of Orthoptera communities between all management types. On croplands, the number of adult individuals and nymphs was influenced by the proportion of grassland in the surrounding landscape and tillage practices. Conservation tillage is most likely the key factor allowing Orthoptera to reproduce on croplands. After up to 24 years of succession, Orthoptera communities of ex-arable grasslands can be considered as completely recovered, as differences to ancient grasslands were minimal. Besides the continuation of low-intensity management, conservation strategies for this region should consider landscape composition and support habitat heterogeneity like ecotones with hemi-boreal forests in grassland-dominated landscapes.

Factors of land abandonment in mountainous Mediterranean areas: the case of Montenegrin settlements.

Land use changes have been investigated in the surroundings of 14 rural Montenegrin settlements in order to get specific information about trends in land abandonment since around 1950. Permanently, seasonally and less inhabited settlements with different geographic conditions were studied. This was done by interviewing local inhabitants, which enabled a holistic approach to reveal the underlying processes of land abandonment. According to the observed patterns of land use change, the study sites can be categorized into intensified, urbanized, extensified, overgrown and forested cases. The category of extensified settlements is characterized by a highly reduced agricultural management intensity, resulting in an increase in grasslands and fruit trees at the expense of cropland. This land use change is mainly related to emigrating and aging inhabitants, having less livestock. Such extensive land use is found in both permanently inhabited and abandoned villages. Only some studied settlements became largely overgrown by bushes and forest. The steep average slope gradients and a large distance to the nearest city are explanatory factors of such land abandonment. Land use intensification takes place in low-lying areas located nearby towns.

147 - Cross-Talk between Two Antioxidants, Thioredoxin Reductase 1 and Heme Oxygenase-1 and Therapeutic Implications in Multiple Myeloma

The intensification of agricultural management has caused some weed species to become rare in arable farming systems. It is difficult to disentangle which management practices are the least harmful for the conservation of rare arable weeds because of their sparse presence. In this research, we overcame the limitations of previous analyses of rare weeds by analyzing them in a large number of plots (1957) at the edges of multiple organic fields (304), which maximized the probability of detecting these species. We evaluated the relationships between farming practices and local site conditions and the presence of rare arable species that are characteristic of cereal fields.We detected 46 of the 65 rare weeds that are known to inhabit the study area, but their frequency was very low. Cereal crops, either alone or in mixtures with legumes, enhanced the probability of finding rare weed species, while fertilization had a detrimental effect. Other management practices that were considered had no effect on the presence of rare arable weeds. However, selected rare species tended to fare better under particular local conditions and to be favored by specific management practices. In contrast, a significant amount of the variance of the rare weed presence was explained by farm-related and field-related random factors. Thus, the occurrence of rare arable species is apparently determined by stochastic factors that may be related to the local species pool that likely depends on the history of fields and farms. Therefore, conservation efforts should be focused on areas currently inhabited by rare arable species.