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Agricultural Intensification (agricultural + intensification)
Selected AbstractsAgricultural Intensification: Will Land Spared from Farming be Land Spared for Nature?CONSERVATION BIOLOGY, Issue 3 2006PAMELA A. MATSON No abstract is available for this article. [source] Domestic Transitions, Desiccation, Agricultural Intensification, and Livelihood Diversification among Rural Households on the Central Plateau, Burkina FasoAMERICAN ANTHROPOLOGIST, Issue 3 2009Colin Thor West ABSTRACT Understanding how and why domestic groups alter their function and form has long been a theme within anthropology. Numerous accounts have detailed the processes that drive household transformations and their underlying mechanisms. Mostly, these studies describe how domestic groups fission and fuse between extended and nuclear forms. In recent years, scholars have emphasized that these transformations should be understood within larger contexts of social and environmental change. Mossi communities on the Central Plateau of Burkina Faso provide an excellent opportunity to explore such processes because the large extended households documented 30 years ago were predicted to decline and eventually disappear. In this study, I examine dynamics of household transformations and test the validity of this prediction. I use perspectives from sustainability science and computer-simulation modeling to understand how regional desiccation, agricultural intensification, and livelihood diversification articulate with domestic transitions. [source] The conservation management of upland hay meadows in Britain: a reviewGRASS & FORAGE SCIENCE, Issue 4 2005R. G. Jefferson Abstract Upland hay meadows conforming to MG3 in the National Vegetation Classification of the UK are a rare habitat in Britain and are largely confined to upland valleys in northern England. Agricultural intensification, particularly ploughing and reseeding and a shift from hay-making to silage production over the last 50 years, has resulted in large losses of species-rich upland hay meadows. Remaining species-rich meadows have been the focus of much nature conservation effort resulting in many of the species-rich sites being protected by statutory designations or through voluntary agri-environment scheme agreements. Research and monitoring has tended to confirm that species richness is maximized by management involving spring and autumn grazing, a mid-July hay cut, no inorganic fertilizer and possibly low levels of farmyard manure. Deviations from this regime result in a loss of species richness. Restoration of semi-improved grassland to swards resembling species-rich MG3 also requires a similar regime but is also dependent on the introduction of seed of appropriate species. The role of Rhinanthus minor as a tool for manipulating meadow biodiversity during restoration management is discussed. Suggestions for future research are outlined. [source] Irrigation Externalities and Agricultural Sustainability in South-eastern NigeriaJOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2004Kevin C. Urama Agricultural intensification by irrigation is increasingly regarded as the key to solving food supply problems in Sub-Saharan Africa. Conversely, mounting empirical evidence suggests that irrigation externalities might preclude long-term sustainability of arable agriculture. Choosing between intensive irrigation schemes and less intensive farming systems is therefore, problematic. The paper examines the implications of irrigation intensification in south-eastern Nigeria using adjacent rain-fed farms as the counterfactual. The analyses found mixed results. When first introduced, the irrigation scheme increased marginal factor productivity and gross margins but this has subsequently declined to the extent that the marginal factor product of land has become negative. The annual yields of the irrigated farms were also less stable than those of the less intensive rain-fed farms. These results indicate the dilemma that irrigation externalities present to sustainable agricultural policy and suggest a need to look again at the potential for developments in rain-fed systems. [source] Effects of predatory ants on lower trophic levels across a gradient of coffee management complexityJOURNAL OF ANIMAL ECOLOGY, Issue 3 2008S. M. Philpott Summary 1Ants are important predators in agricultural systems, and have complex and often strong effects on lower trophic levels. Agricultural intensification reduces habitat complexity, food web diversity and structure, and affects predator communities. Theory predicts that strong top-down cascades are less likely to occur as habitat and food web complexity decrease. 2To examine relationships between habitat complexity and predator effects, we excluded ants from coffee plants in coffee agroecosystems varying in vegetation complexity. Specifically, we studied the effects of eliminating ants on arthropod assemblages, herbivory, damage by the coffee berry borer and coffee yields in four sites differing in management intensification. We also sampled ant assemblages in each management type to see whether changes in ant assemblages relate to any observed changes in top-down effects. 3Removing ants did not change total arthropod densities, herbivory, coffee berry borer damage or coffee yields. Ants did affect densities of some arthropod orders, but did not affect densities of different feeding groups. The effects of ants on lower trophic levels did not change with coffee management intensity. 4Diversity and activity of ants on experimental plants did not change with coffee intensification, but the ant species composition differed. 5Although variation in habitat complexity may affect trophic cascades, manipulating predatory ants across a range of coffee agroecosystems varying in management intensity did not result in differing effects on arthropod assemblages, herbivory, coffee berry borer attack or coffee yields. Thus, there is no clear pattern that top-down effects of ants in coffee agroecosystems intensify or dampen with decreased habitat complexity. [source] The adoption of intensive monocrop horticulture in southern CameroonAGRICULTURAL ECONOMICS, Issue 3 2004James Gockowski Logit; Monocrop; Agricultural intensification; Cash crop synergy Abstract Results from a 1997 survey of 208 households in the humid forest zone of southern Cameroon indicate that African policy makers seeking to intensify agricultural production should focus attention on the horticultural sub-sector. The survey, which gathered information on horticultural production practices, found that the average expenditure on agro-chemical inputs by horticultural producers using monocrop production systems was 190US$/ha, which greatly exceeds the FAO reported national average expenditure of 6.50 US$/ha. A logit model of monocrop adoption indicated that the size of land holding per household had a negative effect on adoption, congruent with population-driven technical change and that increases in unit transportation costs significantly decreased the probability of adoption. These findings suggest that policy makers should target horticultural intensification in areas of higher population density and promote investment in rural roads. The age of the household head had a significant negative and elastic effect on adoption, which in combination with an increase in the cohort of younger farmers in the rural population induced by macro-economic events contributed to the spread of intensified horticulture. In the study area, roughly two-thirds of rural households also produce cocoa and the quantity of cocoa produced was positively associated with adoption of intensive horticultural systems suggesting that export crop promotion indirectly facilitated diversification of agriculture. Women's participation in intensive monocrop production was limited and efforts to promote their greater involvement are recommended. [source] Biodiversity in tropical agroforests and the ecological role of ants and ant diversity in predatory functionECOLOGICAL ENTOMOLOGY, Issue 4 2006STACY M. PHILPOTT Abstract 1.,Intensive agricultural practices drive biodiversity loss with potentially drastic consequences for ecosystem services. To advance conservation and production goals, agricultural practices should be compatible with biodiversity. Traditional or less intensive systems (i.e. with fewer agrochemicals, less mechanisation, more crop species) such as shaded coffee and cacao agroforests are highlighted for their ability to provide a refuge for biodiversity and may also enhance certain ecosystem functions (i.e. predation). 2.,Ants are an important predator group in tropical agroforestry systems. Generally, ant biodiversity declines with coffee and cacao intensification yet the literature lacks a summary of the known mechanisms for ant declines and how this diversity loss may affect the role of ants as predators. 3.,Here, how shaded coffee and cacao agroforestry systems protect biodiversity and may preserve related ecosystem functions is discussed in the context of ants as predators. Specifically, the relationships between biodiversity and predation, links between agriculture and conservation, patterns and mechanisms for ant diversity loss with agricultural intensification, importance of ants as control agents of pests and fungal diseases, and whether ant diversity may influence the functional role of ants as predators are addressed. Furthermore, because of the importance of homopteran-tending by ants in the ecological and agricultural literature, as well as to the success of ants as predators, the costs and benefits of promoting ants in agroforests are discussed. 4.,Especially where the diversity of ants and other predators is high, as in traditional agroforestry systems, both agroecosystem function and conservation goals will be advanced by biodiversity protection. [source] Long-term land-cover changes in the Belgian Ardennes (1775,1929): model-based reconstruction vs. historical mapsGLOBAL CHANGE BIOLOGY, Issue 7 2002C. C. Petit Abstract Understanding long-term human-environment interactions requires historical reconstruction of past land-cover changes. The objective of this study is to reconstruct past land-use and land-cover changes in a rural municipality of the Belgian Ardennes over the last 250 years. Two approaches were compared. The first approach produced backward projections based on a mechanistic model which computes the demand for different land uses under the assumption of an equilibrium between the production and consumption of resources. The second approach involved using a series of historical maps to extract directly land-use areas. A stochastic Markov chain model was also used to project backward missing land-cover data in the time series. The consistency between the results obtained with the different approaches suggests that land-use area can be successfully reconstructed on the basis of the mechanistic model, under conditions of a subsistence farming system and a closed economy. Land-use/cover changes in the Belgian Ardennes from 1775 to 1929 were more driven by the interventionist measures of the Belgian government and by technological progress than by the ,pressure' of the growing population and livestock. Thanks to agricultural intensification, a decrease in land under human use was supporting increasing human and livestock populations from 1846 to 1880. Reforestation has accelerated since the mid-19th century. This case study illustrates the highly dynamic and non-linear character of land-use change trajectories over long time periods and their strong interactions with the history of societies. [source] Between-year variations in Little Bustard Tetrax tetrax population densities are influenced by agricultural intensification and rainfallIBIS, Issue 3 2010ANA DELGADO The Little Bustard is suffering a widespread population decline mainly due to agricultural intensification. This study evaluates the effects of intensification level, habitat availability and rainfall on the population dynamics of this species. The population density of males was monitored for 7 years (2002,2008) at 184 points located within three sites with contrasting levels of agricultural intensification in southern Portugal. Densities decreased along the intensification gradient from 8.2 to 2.3 males,/,km2. Overall, there was an approximately 50% population decline during the period 2002,2008, driven by a decline observed in one of the less intensive sites, whereas in the other two sites densities remained fairly constant. Yearly variations in male densities were influenced by intensification level, amount of grassland habitat and rainfall patterns. Thus, agricultural intensification is having a negative effect on population densities of this threatened species, particularly through the loss of grasslands (fallow fields and pastures) suitable for displaying males. The results also suggest a positive impact of rainfall on male densities, although this is more likely in grasslands within less intensive agricultural regions of poorer soil quality, where higher breeding male densities occur. Grassland habitat quality, driven by both climate and human management, probably plays a major role in the population dynamics of this threatened steppe bird in its strongholds. [source] Nest-site selection by Great Bustards Otis tarda suggests a trade-off between concealment and visibilityIBIS, Issue 1 2010MARINA MAGAÑA Great Bustards Otis tarda have expanded their habitat range from historical occupancy of natural steppes to arable farmland, where the species initially benefited from favourable feeding conditions. More recently, the species has suffered severe declines due partly to agricultural intensification. Nest losses and juvenile mortality are amongst the factors most seriously affecting survival probabilities of many populations of this endangered species, suggesting that management of nesting habitats would bring conservation benefits. We studied nest-site selection in a Great Bustard population of central Spain by radiotracking 42 females for periods of between 1 and 4 years. Females selected nest-sites in fallows or cereal fields, in areas of low patch-type diversity, far from human infrastructure, and with good horizontal visibility. These results suggest that females look for shelter, but also need to have good visibility while incubating, and they support the hypothesis that nest selection is a trade-off between concealment and visibility. We interpret both preferences as adaptations to reduce predation pressure, one of the main causes of nest failure in this species. Nests were placed on slopes significantly orientated to the southeast, which suggests that females also seek sites protected from the cold north-westerly winds that are prevalent in the study area. To reduce nest destruction, harvesting should be delayed as long as possible and habitat conservation measures should not be restricted to lek sites but also include nesting areas, which are frequently located far from leks. [source] Determining the effects of habitat management and climate on the population trends of a declining steppe birdIBIS, Issue 3 2009MARÍA PAULA DELGADO The Little Bustard Tetrax tetrax is one of the most threatened steppe bird species in Europe, due mainly to agricultural intensification. Despite the relative importance of the Iberian population (approximately 50% of the global population) little is known about its dynamics and trends, especially in core distribution areas. This study evaluates the influences of meteorological factors and land management on the oscillations and medium-term trends of two Little Bustard populations in Central Spain. During 2001,2007, surveys of breeding male and female Little Bustards were carried out in two central Spanish locations: Valdetorres, in Special Protection Area (SPA) no. 139 (1600 ha), and Campo Real, in Important Bird Area (IBA) no. 075 (1150 ha). Densities were 3.3,4.0 and 1.1,2.1 males/km2 in Campo Real, and 1.8,2.2 and 0.6,1.3 females/km2 in Valdetorres. The sex ratio was biased towards males in both cases. Both populations declined during 2001,2007, especially in Valdetorres (60%). Variation in habitat composition did not explain variation in the numbers of males. Both populations were influenced by total precipitation in the preceding October,May period. Results suggest that the Little Bustard may be sensitive to future climate trends in Europe. Finally, different simulated demographic scenarios suggest that low female survival and productivity may be the immediate cause of the decline in Little Bustard populations, which is consistent with their sensitivity to climatic conditions. [source] The recent declines of farmland bird populations in Britain: an appraisal of causal factors and conservation actionsIBIS, Issue 4 2004Ian Newton In this paper, the main aspects of agricultural intensification that have led to population declines in farmland birds over the past 50 years are reviewed, together with the current state of knowledge, and the effects of recent conservation actions. For each of 30 declining species, attention is focused on: (1) the external causes of population declines, (2) the demographic mechanisms and (3) experimental tests of proposed external causal factors, together with the outcome of (4) specific conservation measures and (5) agri-environment schemes. Although each species has responded individually to particular aspects of agricultural change, certain groups of species share common causal factors. For example, declines in the population levels of seed-eating birds have been driven primarily by herbicide use and the switch from spring-sown to autumn-sown cereals, both of which have massively reduced the food supplies of these birds. Their population declines have been associated with reduced survival rates and, in some species, also with reduced reproductive rates. In waders of damp grassland, population declines have been driven mainly by land drainage and the associated intensification of grassland management. This has led to reduced reproductive success, as a result of lowered food availability, together with increased disturbance and trampling by farm stock, and in some localities increased nest predation. The external causal factors of population decline are known (with varying degrees of certainty) for all 30 species considered, and the demographic causal factors are known (again with varying degrees of certainty) for 24 such species. In at least 19 species, proposed causal factors have been tested and confirmed by experiment or by local conservation action, and 12 species have been shown to benefit (in terms of locally increased breeding density) from options available in one or more agri-environment schemes. Four aspects of agricultural change have been the main drivers of bird population declines, each affecting a wide range of species, namely: (1) weed-control, mainly through herbicide use; (2) the change from spring-sown to autumn-sown cereal varieties, and the associated earlier ploughing of stubbles and earlier crop growth; (3) land drainage and associated intensification of grassland management; and (4) increased stocking densities, mainly of cattle in the lowlands and sheep in the uplands. These changes have reduced the amounts of habitat and/or food available to many species. Other changes, such as the removal of hedgerows and ,rough patches', have affected smaller numbers of species, as have changes in the timings of cultivations and harvests. Although at least eight species have shown recent increases in their national population levels, many others seem set to continue declining, or to remain at a much reduced level, unless some relevant aspect of agricultural practice is changed. [source] Where within a geographical range do species survive best?INSECT CONSERVATION AND DIVERSITY, Issue 1 2008A matter of scale Abstract., 1Opinions differ as to whether declining species are most likely to survive in central or peripheral parts of their distributions. The former pattern is likely to be driven by high extinction risks in peripheral areas; the latter by gradients of extinction risk. 2At a continental scale of analysis, the declining butterfly Euphydryas aurinia survived best in southern and eastern countries within Europe. This was statistically associated with geographical variation in agricultural intensification. At this scale of analysis, there was a gradient of survival, caused by a gradient of agricultural intensification. 3Within England and Wales, survival was greatest in population concentrations, or core areas; that is in 10-km grid squares that were surrounded by other 10-km grid squares that also contained populations of E. aurinia. In the English county of Dorset, populations were also most likely to be found in core areas; that is in habitat patches that were close to other populated habitat patches. 4In this system, there is support for two patterns of decline. At a coarse scale, there is a geographical gradient of habitat degradation, associated with agricultural intensification. But within a region where decline has taken place, populations survive best in core areas, where aggregations of habitat support viable metapopulation dynamics. 5Large-scale geographical patterns of decline towards the periphery (or other locations within) the distribution of a species do not negate the validity of conservation strategies based on core-margin population dynamic principles. Core areas within each country or region represent appropriate targets for conservation action. [source] National-scale metacommunity dynamics of carabid beetles in UK farmlandJOURNAL OF ANIMAL ECOLOGY, Issue 2 2008David R. Brooks Summary 1Understanding the wide-scale processes controlling communities across multiple sites is a foremost challenge of modern ecology. Here, data from a nation-wide network of field sites are used to describe the metacommunity dynamics of arable carabid beetles. This is done by modelling how communities are structured at a local level, by changes in the environment of the sampled fields and, at a regional level, by fitting spatial parameters describing latitudinal and longitudinal gradients. 2Local and regional processes demonstrated independent and significant capacities for structuring communities. Within the local environment, crop type was found to be the primary determinant of carabid community composition. The regional component included a strong response to a longitudinal gradient, with significant increases in diversity in an east-to-west direction. 3Carabid metacommunities seem to be structured by a combination of species sorting dynamics, operating at two different, but equally important, spatial scales. At a local scale, species are sorted along a resource gradient determined by crop type. At a wider spatial scale species appear to be sorted along a longitudinal gradient. 4Nation-wide trends in communities coincided with known gradients of increased homogeneity of habitat mosaics and agricultural intensification. However, more work is required to understand fully how communities are controlled by the interaction of crops with changes in landscape structure at different spatial scales. 5We conclude that crop type is a powerful determinant of carabid biodiversity, but that it cannot be considered in isolation from other components of the landscape for optimal conservation policy. [source] 100 years of change: examining agricultural trends, habitat change and stakeholder perceptions through the 20th centuryJOURNAL OF APPLIED ECOLOGY, Issue 2 2009Martin Dallimer Summary 1The 20th century has witnessed substantial increases in the intensity of agricultural land management, much of which has been driven by policies to enhance food security and production. The knock-on effects in agriculturally dominated landscapes include habitat degradation and biodiversity loss. We examine long-term patterns of agricultural and habitat change at a regional scale, using the Peak District of northern England as a case study. As stakeholders are central to the implementation of successful land-use policy, we also assess their perceptions of historical changes. 2In the period 1900 to 2000, there was a fivefold rise in sheep density, along with higher cattle density. We found a reduction in the number of farms, evidence of a shift in land ownership patterns, and increased agricultural specialization, including the virtual disappearance of upland arable production. 3Despite previous studies showing a substantial loss in heather cover, we found that there had been no overall change in the proportion of land covered by dwarf shrub moor. Nonetheless, turnover rates were high, with only 55% of sampled sites maintaining dwarf shrub moor coverage between 1913 and 2000. 4Stakeholders identified many of the changes revealed by the historical data, such as increased sheep numbers, fewer farms and greater specialization. However, other land-use changes were not properly described. For instance, although there had been no overall change in the proportion of dwarf shrub moor and the size of the rural labour force had not fallen, stakeholders reported a decline in both. Spatial heterogeneity of the changes, shifting baselines and problems with historical data sources might account for some of these discrepancies. 5Synthesis and applications. A marked increase in sheep numbers, combined with general agricultural intensification, have been the dominant land-use processes in the Peak District during the 20th century. Stakeholders only correctly perceived some land-use changes. Policy and management objectives should therefore be based primarily on actual historical evidence. However, understanding stakeholder perceptions and how they differ from, or agree with, the available evidence will contribute to the successful uptake of land management policies and partly determine the costs of policy implementation. [source] Minimal effects of wind turbines on the distribution of wintering farmland birdsJOURNAL OF APPLIED ECOLOGY, Issue 6 2008Claire L. Devereux Summary 1Energy production from wind power is increasing rapidly in Europe to help combat the threats from global warming. For example, the European Commission have set a target for 20% of EU energy to come from renewable sources by 2020. In recent decades, biodiversity on European farmland has fallen dramatically due to agricultural intensification. Agri-environment schemes (AES) have been implemented across the EU, in part at least, to combat these declines. Significant numbers of turbines are, and will be, built on farmland. There is, therefore, a potential conflict between wind turbines and AES on farmland. 2Various mechanisms potentially cause wind turbines to alter bird distribution including noise and physical structure. 3We show that turbine location (controlling for other effects such as boundary location and crop type) did not affect the distribution of four functional groups of wintering farmland birds (seed-eaters, corvids, gamebirds and Eurasian skylarks) at differing distances from wind turbines ranging from 0,150 m to 600,750 m. The only species for which distribution was related to the presence of wind turbines was the largest and least manoeuvrable (common pheasant Phasianus colchicus L.). 4In a further analysis of data collected at 0,75 m and 75,150 m from turbines, we found no evidence to suggest that farmland birds in our study avoided areas close to wind turbines. 5Synthesis and applications. This is the first evidence suggesting that the present and future location of large numbers of wind turbines on European farmland is unlikely to have detrimental effects on farmland birds (at least for those species included in our study). This should be welcome news for nature conservationists, wind energy companies and policy-makers. However, our work is only a first step, as there may be potential influences of wind turbines on bird distribution during the breeding season. [source] Testing biotic indicator taxa: the sensitivity of insectivorous mammals and their prey to the intensification of lowland agricultureJOURNAL OF APPLIED ECOLOGY, Issue 1 2008Michael J. O. Pocock Summary 1Changes to agricultural policy aim to extensify agriculture and increase biodiversity. However, it is not known how sensitive many taxa are to intensification. Sensitive taxa could be used as biotic indicators, to assess changes over time and the effectiveness of policy changes. 2We sampled shrews, bats and their prey (beetles, flies and moths) on matched pairs of sites and assessed the response in their abundance to aspects of intensification: increased agrochemical inputs (using abundance on matched organic and conventional cereal fields as a proxy), the switch from hay to silage (using abundance on matched hay and silage fields) and boundary loss (using abundance in the field and near the boundary as a proxy, in cereal and grass separately). We quantified the abundance-derived sensitivity of the taxa in order to assess their use as biotic indicators. 3There was substantial variation in the sensitivity of taxa to the three aspects of intensification. Most estimates (51%) of sensitivity to boundary loss were significant, but only 8% for increased agrochemical inputs and 16% for the switch from hay to silage. Sensitivity to one aspect of intensification was not significantly related to sensitivity to another. 4Insectivorous mammals were relatively insensitive to increased agrochemical inputs and the switch from hay to silage, but strongly sensitive to boundary loss. 5Taxa with significant sensitivity to increased agrochemical inputs included some Carabidae and Diptera. We found fewer significant differences in abundance between organic and conventional farms than previous workers, probably because we controlled for boundary characteristics, suggesting that the quality of field boundaries is important in influencing biodiversity differences between organic and conventional farms. 6The switch from hay to silage had a positive effect on some Coleoptera and Diptera but a substantial negative effect on Hepialidae (Lepidoptera). 7Synthesis and applications. The recorded sensitivity of taxa to changes in agricultural practices is highly variable. Therefore, the selection of biotic indicator taxa of agricultural intensification is not straightforward. If surveys of biotic indicator taxa are used to assess the effectiveness of changes in agricultural practice, empirical evidence should be used to select suitable taxa. [source] Editors' Introduction: Birds and AgricultureJOURNAL OF APPLIED ECOLOGY, Issue 5 2000S.J. Ormerod 1.,Around 10% of recent papers in the Journal of Applied Ecology have examined interactions between birds and agriculture. This statistic reveals the important role now played by ecologists in assessing the effects of agricultural development worldwide. It also reflects the position of birds as both indicators and targets of agricultural change: their patterns of behaviour, distribution, seasonal phenology and demography track closely onto the spatial and temporal scales of agricultural intensification. 2.,Papers in this Special Profile illustrate how research in this sphere has shifted towards assessing the processes by which birds are affected ecologically by agricultural change. The works examine spatial patterns in extinction; assess long-term trends in bird abundance and agricultural practice; reveal how foraging and breeding performance in farmland birds varies between habitats; and evaluate the role of large-scale modelling in examining hypotheses about the influences of land management on birds. The final paper shows that birds can have intrinsically positive value in agricultural systems. 3.,All the papers propose management prescriptions for agricultural areas that blend the microscopic , for example, how to modify local land structure to benefit birds , and the macroscopic , for example, by suggested inputs into land-use policy. Perhaps most pertinent is the key conclusion that agricultural change is multivariate, so that straightforward univariate effects on birds are unlikely. Restoration of impacted populations might therefore require holistic strategies that encourage appropriately scaled agricultural extensification. Success would be most likely if farmers, conservationists and other key players were engaged collaboratively in the process. 4.,Current ideas about restoring farmland bird populations share a common assumption: if agricultural practice has reduced populations hitherto, then agricultural practice can restore the losses. We suggest that this assumption carries a range of predictions that now require testing through sustainable farm management , a situation ideally suited to ,BACI' style experiments. 5.,We reiterate the need to expand work on other groups of organisms affected negatively or positively by agricultural management to allow a broader perspective of impacts or benefits. [source] Habitat models of bird species' distribution: an aid to the management of coastal grazing marshesJOURNAL OF APPLIED ECOLOGY, Issue 5 2000T. P. Milsom 1.,Coastal grazing marshes comprise an important habitat for wetland biota but are threatened by agricultural intensification and conversion to arable farmland. In Britain, the Environmentally Sensitive Area (ESA) scheme addresses these problems by providing financial incentives to farmers to retain their grazing marshes, and to follow conservation management prescriptions. 2.,A modelling approach was used to aid the development of management prescriptions for ground-nesting birds in the North Kent Marshes ESA. This ESA contains the largest area of coastal grazing marsh remaining in England and Wales (c. 6500 ha) and supports nationally important breeding populations of lapwing Vanellus vanellus and redshank Tringa totanus. 3.,Counts of ground-nesting birds, and assessments of sward structure, surface topography and wetness, landscape structure and sources of human disturbance were made in 1995 and again in 1996, on 19 land-holdings with a combined area of c. 3000 ha. The land-holdings varied from nature reserves at one extreme to an intensive dairy farm at the other. 4.,Models of relationship between the presence or absence of ground-nesting birds and the grazing marsh habitat in each of c. 430 marshes were constructed using a generalized linear mixed modelling (GLMM) method. This is an extension to the conventional logistic regression approach, in which a random term is used to model differences in the proportion of marshes occupied on different land-holdings. 5.,The combined species models predicted that the probability of marshes being occupied by at least one ground-nesting species increased concomitantly with the complexity of the grass sward and surface topography but decreased in the presence of hedgerows, roads and power lines. 6.,Models were also prepared for each of the 10 most widespread species, including lapwing and redshank. Their composition differed between species. Variables describing the sward were included in models for five species: heterogeneity of sward height tended to be more important than mean sward height. Surface topography and wetness were important for waders and wildfowl but not for other species. Effects of boundaries, proximity to roads and power lines were included in some models and were negative in all cases. 7.,Binomial GLMMs are useful for investigating habitat factors that affect the distribution of birds at two nested spatial scales, in this case fields (marshes) grouped within farms. Models of the type presented in this paper provide a framework for targeting of conservation management prescriptions for ground-nesting birds at the field scale on the North Kent Marshes ESA and on lowland wet grassland elsewhere in Europe. [source] The impact of integrated aquaculture,agriculture on small-scale farms in Southern MalawiAGRICULTURAL ECONOMICS, Issue 1 2010Madan M. Dey Aquaculture; Malawi; Participatory research; Technical efficiency Abstract Sustainable agricultural intensification is an urgent challenge for Sub-Saharan Africa. One potential solution is to rely on local farmers' knowledge for improved management of diverse on-farm resources and integration among various farm enterprises. In this article, we analyze the farm-level impact of one recent example, namely the integrated aquaculture,agriculture (IAA) technologies that have been developed and disseminated in a participatory manner in Malawi. Based on a 2004 survey of 315 respondents (166 adopters and 149 nonadopters), we test the hypothesis that adoption of IAA is associated with improved farm productivity and more efficient use of resources. Estimating a technical inefficiency function shows that IAA farms were significantly more efficient compared to nonadopters. IAA farms also had higher total factor productivity, higher farm income per hectare, and higher returns to family labor. [source] Soil carbon sequestration in China through agricultural intensification, and restoration of degraded and desertified ecosystems,LAND DEGRADATION AND DEVELOPMENT, Issue 6 2002R. Lal Abstract The industrial emission of carbon (C) in China in 2000 was about 1,Pg,yr,1, which may surpass that of the United States (1,84,Pg,C) by 2020. China's large land area, similar in size to that of the United States, comprises 124,Mha of cropland, 400,Mha of grazing land and 134,Mha of forestland. Terrestrial C pool of China comprises about 35,60,Pg in the forest and 120,186,Pg in soils. Soil degradation is a major issue affecting 145,Mha by different degradative processes, of which 126,Mha are prone to accelerated soil erosion. Total annual loss by erosion is estimated at 5,5,Pg of soil and 15,9,Tg of soil organic carbon (SOC). Erosion-induced emission of C into the atmosphere may be 32,64,Tg,yr,1. The SOC pool progressively declined from the 1930s to 1980s in soils of northern China and slightly increased in those of southern China because of change in land use. Management practices that lead to depletion of the SOC stock are cultivation of upland soils, negative nutrient balance in cropland, residue removal, and soil degradation by accelerated soil erosion and salinization and the like. Agricultural practices that enhance the SOC stock include conversion of upland to rice paddies, integrated nutrient management based on liberal use of biosolids and compost, crop rotations that return large quantities of biomass, and conservation-effective systems. Adoption of recommended management practices can increase SOC concentration in puddled soil, red soil, loess soils, and salt-affected soils. In addition, soil restoration has a potential to sequester SOC. Total potential of soil C sequestration in China is 105,198,Tg,C,yr,1 of SOC and 7,138,Tg,C,yr,1 for soil inorganic carbon (SIC). The accumulative potential of soil C sequestration of 11,Pg at an average rate of 224,Tg,yr,1 may be realized by 2050. Soil C sequestration potential can offset about 20 per cent of the annual industrial emissions in China. Copyright © 2002 John Wiley & Sons, Ltd. [source] Mammals, agri-environment schemes and set-aside , what are the putative benefits?MAMMAL REVIEW, Issue 4 2007D. W. MACDONALD ABSTRACT 1The impacts of agricultural intensification on farmland wildlife have been the subject of increasing concern, particularly over the last two decades. Population declines have occurred for a number of mammalian species, sometimes drastically so, and changes in farming practice are believed to be significant contributory factors. 2The major policy instruments for delivering environmental benefits on farmland are agri-environment schemes. These encourage farmers to adopt more environmentally sensitive farming practices to promote farmland biodiversity. Additionally, compulsory set-aside, which reduces agricultural surplus, could also have positive impacts on wildlife. In this paper we consider some of the putative benefits of agri-environment schemes and set-aside for mammals. 3We review how establishment and management options within agri-environment schemes and set-aside might affect habitat resources for mammals. For example, conservation headlands increase plant and invertebrate resources within the crop edge for mammals such as wood mice. Grassy field margins can support communities of smaller mammals, and hedgerows may act as important commuting and hunting routes. Their potential will depend on factors such as seed mixtures used, timing and severity of cutting, and length of time they have been in place. 4At a farm level, habitat heterogeneity may be increased through organic agriculture, which is supported by some agri-environment schemes. Studies suggest significant benefits to mammals, including wood mice and bats. However, it is increasingly recognized that effective conservation of farmland mammals must seek solutions at the landscape scale, addressing such issues as habitat connectivity between farms. One approach may be the better targeting of scheme agreements. 5We suggest that agri-environment schemes and set-aside can contribute to the conservation of mammals on farmland. Recent policy changes are likely to have further positive impacts on farmland wildlife but appropriate mammal monitoring programmes must be developed rigorously to assess their effects. [source] Domestic Transitions, Desiccation, Agricultural Intensification, and Livelihood Diversification among Rural Households on the Central Plateau, Burkina FasoAMERICAN ANTHROPOLOGIST, Issue 3 2009Colin Thor West ABSTRACT Understanding how and why domestic groups alter their function and form has long been a theme within anthropology. Numerous accounts have detailed the processes that drive household transformations and their underlying mechanisms. Mostly, these studies describe how domestic groups fission and fuse between extended and nuclear forms. In recent years, scholars have emphasized that these transformations should be understood within larger contexts of social and environmental change. Mossi communities on the Central Plateau of Burkina Faso provide an excellent opportunity to explore such processes because the large extended households documented 30 years ago were predicted to decline and eventually disappear. In this study, I examine dynamics of household transformations and test the validity of this prediction. I use perspectives from sustainability science and computer-simulation modeling to understand how regional desiccation, agricultural intensification, and livelihood diversification articulate with domestic transitions. [source] The value of agri-environment schemes for macro-invertebrate feeders: hedgehogs on arable farms in BritainANIMAL CONSERVATION, Issue 5 2010A. R. Hof Abstract Agri-environment schemes have been introduced in countries throughout the world in an attempt to reverse the negative impacts of agricultural intensification on biodiversity and the environment. There have been some investigations into the effectiveness of such schemes, which show mixed outcomes but little is known with regard to mammals. The hedgehog is a generalist predator and preys on, among others, an array of macro-invertebrates, prey important for many other taxa. For a non-volant species, it is highly mobile in the environment and should thus be less susceptible to negative effects of habitat fragmentation caused by agricultural intensification. However, it has recently been included in the UK Biodiversity Action Plan, as a result of evidence of a significant decline. We studied the importance of agri-environment schemes for hedgehogs using radio-tracking on arable farms. Both agri-environment field margins and hedgerows appear to be very valuable for hedgehogs. Both habitat types were intensively utilized by hedgehogs; higher food availability/accessibility on agri-environment field margins and higher food or nest site availability along edges and/or lower predation risk by badgers in arable areas may explain these preferences. Badger predation of hedgehogs was high in the study site and the main cause of death. Our study emphasizes the importance of natural habitat in an agricultural landscape and shows that agri-environment schemes can be beneficial to this generalist macro-invertebrate feeder. The implementation of agri-environment schemes that include wide field margins and dense, well-established hedgerows on farmland could significantly contribute to the viability of hedgehog populations in intensive arable-farming landscapes, and by implication benefit other macro-invertebrate feeders. [source] | ||||||||||||||||||||||||||||