10 research outputs found
The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands
Intensively managed grasslands are globally prominent ecosystems. We investigated whether experimental increases in plant diversity in intensively managed grassland communities can increase their resource use efficiency. This work consisted of a coordinated, continental-scale 33-site experiment. The core design was 30 plots, representing 15 grassland communities at two seeding densities. The 15 communities were comprised of four monocultures (two grasses and two legumes) and 11 four-species mixtures that varied in the relative abundance of the four species at sowing. There were 1028 plots in the core experiment, with another 572 plots sown for additional treatments. Sites agreed a protocol and employed the same experimental methods with certain plot management factors, such as seeding rates and number of cuts, determined by local practice. The four species used at a site depended on geographical location, but the species were chosen according to four functional traits: a fast-establishing grass, a slow-establishing persistent grass, a fast-establishing legume, and a slow-establishing persistent legume. As the objective was to maximize yield for intensive grassland production, the species chosen were all high-yielding agronomic species. The data set contains species-specific biomass measurements (yield per species and of weeds) for all harvests for up to four years at 33 sites. Samples of harvested vegetation were also analyzed for forage quality at 26 sites. Analyses showed that the yield of the mixtures exceeded that of the average monoculture in >97% of comparisons. Mixture biomass also exceeded that of the best monoculture (transgressive overyielding) at about 60% of sites. There was also a positive relationship between the diversity of the communities and aboveground biomass that was consistent across sites and persisted for three years. Weed invasion in mixtures was very much less than that in monocultures.
These data should be of interest to ecologists studying relationships between diversity and ecosystem function and to agronomists interested in sustainable intensification. The large spatial scale of the sites provides opportunity for analyses across spatial (and temporal) scales. The database can also complement existing databases and meta-analyses on biodiversity–ecosystem function relationships in natural communities by focusing on those same relationships within intensively managed agricultural grasslands
Assessing the relationship between biodiversity and stability of ecosystem function – is the coefficient of variation always the best metric?
The role of biodiversity in regulating the stability of ecosystem functioning (functional stability) has importance for the reliable delivery of ecosystem services. To date, ecological studies that aim to measure stability in ecosystem function across a range in diversity have almost universally used the coefficient of variation (CV, the ratio of standard deviation of functional response to its mean) in reaching conclusions. We argue that the use of CV for this purpose can lead to misleading conclusions on functional stability. We use illustrative scenarios to show that an assessment of functional stability based on the CV is not as effective in many cases as one based on joint consideration of mean and standard deviation, and may be completely misleading, especially where low values of functional response are a desirable outcome. Faced with similar questions, agronomic studies that aim to assess the stability of ecosystem function (comparison of yield of different varieties within and across different sites) take both the average response and variability within- and between-sites into consideration. We argue that the way stability is measured should be appropriate for the questions about the delivery of ecosystem services that are being addressed. Assessment of the importance of diversity in providing ecosystem services for society is more likely to be made on socio-economic evaluation of trade-offs between mean and variability of the function rather than its stability as measured by the coefficient of variation
Regional and farm system drivers of avian biodiversity within agriculture ecosystems
Rethinking Agricultural Systems in the UK, St. Catherine's College, Oxford, 18-19 December 2013Aspects of Applied BiologyFarm-wide bird surveys were carried out on 119 grass-based farms located in three
separate regions in Ireland during the winter and breeding seasons. Data relating to
livestock production system (dairy or non-dairy) and participation in the Irish agrienvironment
scheme (AES) at the time, the Rural Environmental Protection Scheme,
were collected. GLMMs were used to establish the factors influencing bird populations
during the winter and breeding season. Region and farming system had significant effects
on avian biodiversity and there were frequently greater numbers on more intensively
managed dairy farms, compared with less intensive non-dairy farms. AES participation
had no significant effect on bird populations. Our findings demonstrate a clear influence
of region and farm system on avian biodiversity, and suggest that the greater resource
availability in more intensive farm systems may actually be beneficial for certain
components of farmland biodiversity.AD 22/01/201
Response of farmland biodiversity to the introduction of bioenergy crops: effects of local factors and surrounding landscape context
The recent growth in bioenergy crop cultivation, stimulated by the need to implement measures to reduce net CO2 emissions, is driving major land-use changes with consequences for biodiversity and ecosystem service provision. Although the type of bioenergy crop and its associated management is likely to affect biodiversity at the local (field) scale, landscape context and its interaction with crop type may also influence biodiversity on farms. In this study, we assessed the impact of replacing conventional agricultural crops with two model bioenergy crops (either oilseed rape Brassica napus or Miscanthus à  giganteus) on vascular plant, bumblebee, solitary bee, hoverfly and carabid beetle richness, diversity and abundance in 50 sites in Ireland. We assessed whether within-field biodiversity was also related to surrounding landscape structure. We found that local- and landscape-scale variables correlated with biodiversity in these agricultural landscapes. Overall, the differences between the bioenergy crops and the conventional crops on farmland biodiversity were mostly positive (e.g. higher vascular plant richness in Miscanthus planted on former conventional tillage, higher solitary bee abundance and richness in Miscanthus and oilseed rape compared with conventional crops) or neutral (e.g. no differences between crop types for hoverflies and bumblebees). We showed that these crop type effects were independent of (i.e. no interactions with) the surrounding landscape composition and configuration. However, surrounding landscape context did relate to biodiversity in these farms, negatively for carabid beetles and positively for hoverflies. Although we conclude that the bioenergy crops compared favourably with conventional crops in terms of biodiversity of the taxa studied at the field scale, the effects of large-scale planting in these landscapes could result in very different impacts. Maintaining ecosystem functioning and the delivery of ecosystem services will require a greater understanding of impacts at the landscape scale to ensure the sustainable development of climate change mitigation measures.This research was funded by the SIMBIOSYS Project (http://www.tcd.ie/research/simbiosys/, 2007-B-CD-1-S1) as part of the Science, Technology, Research and Innovation for the Environment (STRIVE) Programme, financed by the Irish Government under the National Development Plan 2007–2013, administered on behalf of the Department of the Environment, Heritage and Local Government by the Irish Environmental Protection Agency.peer-reviewe
Konflik batin tokoh utama novel Orang-Orang Proyek karya Ahmad Tohari dalam tinjauan psikologi sastra dan relevansinya sebagai bahan pembelajaran sastra di SMA kelas XI semester 1
The recent growth in bioenergy crop cultivation, stimulated by the need to implement measures to reduce net CO2 emissions, is driving major land-use changes with consequences for biodiversity and ecosystem service provision. Although the type of bioenergy crop and its associated management is likely to affect biodiversity at the local (field) scale, landscape context and its interaction with crop type may also influence biodiversity on farms. In this study, we assessed the impact of replacing conventional agricultural crops with two model bioenergy crops (either oilseed rape Brassica napus or Miscanthus à  giganteus) on vascular plant, bumblebee, solitary bee, hoverfly and carabid beetle richness, diversity and abundance in 50 sites in Ireland. We assessed whether within-field biodiversity was also related to surrounding landscape structure. We found that local- and landscape-scale variables correlated with biodiversity in these agricultural landscapes. Overall, the differences between the bioenergy crops and the conventional crops on farmland biodiversity were mostly positive (e.g. higher vascular plant richness in Miscanthus planted on former conventional tillage, higher solitary bee abundance and richness in Miscanthus and oilseed rape compared with conventional crops) or neutral (e.g. no differences between crop types for hoverflies and bumblebees). We showed that these crop type effects were independent of (i.e. no interactions with) the surrounding landscape composition and configuration. However, surrounding landscape context did relate to biodiversity in these farms, negatively for carabid beetles and positively for hoverflies. Although we conclude that the bioenergy crops compared favourably with conventional crops in terms of biodiversity of the taxa studied at the field scale, the effects of large-scale planting in these landscapes could result in very different impacts. Maintaining ecosystem functioning and the delivery of ecosystem services will require a greater understanding of impacts at the landscape scale to ensure the sustainable development of climate change mitigation measures.This research was funded by the SIMBIOSYS Project (http://www.tcd.ie/research/simbiosys/, 2007-B-CD-1-S1) as part of the Science, Technology, Research and Innovation for the Environment (STRIVE) Programme, financed by the Irish Government under the National Development Plan 2007–2013, administered on behalf of the Department of the Environment, Heritage and Local Government by the Irish Environmental Protection Agency
A comparison of winter bird communities in agricultural grassland and cereal habitats in Ireland: implications for Common Agricultural Policy reform
Capsule. In winter, grassland sites had greater bird numbers compared to winter cereals, but a number of species of conservation concern were exclusively recorded on winter cereals.
Aims. To compare the winter bird communities in grassland and winter cereal fields.
Methods. Grassland and winter cereal fields were surveyed for overwintering birds in a landscape of mixed grassland and arable agriculture.
Results. Generalized Linear Models demonstrated that total bird abundance, the mean abundance of the majority of ecological groups and that of several common species, were significantly greater in grassland compared with winter cereal fields. However, a number of species of conservation concern, e.g. Skylark Aluda arvensis, were observed only on winter cereal fields. Only a minority of bird variables showed a positive response to field size. Of these, total bird species richness and the Shannon and Simpson's diversity indices showed positive significant responses to increasing field size, which may alternatively and perhaps more correctly be interpreted as a positive response to field boundary density within the farmed landscape.
Conclusions. Farmland habitats are important for the provision of overwintering resources for birds, and policy directed towards bird conservation should target the management of locally significant habitat types. The implications of these findings are discussed in light of the proposed revision of the Common Agricultural Policy in 2014, particularly the proposed measure for crop diversification.Author has checked copyrightkpw13/5/1
The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands
Different bioindicators measured at different spatial scales vary in their response to agricultural intensity
Ecologically, potential bioindicator taxa operate at different scales within agricultural ecosystems, and thereby provide a means to investigate the influence of changing management practice on biological diversity at different scales within the agro-ecosystem. Surveys of grassland plant species at field level, parasitoid Hymenoptera at the field and farm scale, and bird populations and habitats at farm scale were carried out on 119 grass-based farms across three regions in the Republic of Ireland. In addition, habitat richness and aquatic macroinvertebrates were quantified at landscape scale. Agricultural intensity on the surveyed farms was quantified by mean farm stocking rate, calculated as livestock units per ha (LU/ha), and generalised linear mixed models used to evaluate relationships between stocking rate and the incidence of chosen bioindicator groups. Field scale bioindicators (plant species richness and parasitoid taxon richness and abundance) were negatively associated with mean farm stocking rate. Over much of its observed range, mean farm stocking rate was positively associated with total bird species richness and abundance, and the species richness and abundance of farmland bird indicator species recorded in the winter season. However, these relationships were quadratic, and above a relatively high upper limit of 2.5–3.5 LU/ha, further increase in farm stocking rate had a negative influence. Results demonstrate that different bioindicators measured at different spatial scales vary in their response to agricultural intensity. The lack of a consistent bioindicator response to farm stocking rate suggests that within predominantly farmed regions, maximising biodiversity requires a careful targeting and monitoring with bioindicator taxa that are informative of influences at relevant operational scales. The insights provided may then be much more informative for the design and implementation of agri-environment measures that maximise biodiversity within farmed landscapes.DG 19/11/201
Data Paper. Data Paper
<h2>File List</h2><div>
<p><a href="site_info.csv">site_info.csv</a> (MD5: 7393db4a89f77a2e2a56f9047bafcc7a)</p>
<p><a href="biomass.csv">biomass.csv</a> (MD5:f97a1f933698f668db3048419592b003 )</p>
<p><a href="forage_quality.csv">forage_quality.csv</a> (MD5: 8b12dc683a54f9b2a5509434ea99a48e)</p>
<p><a href="climate.csv">climate.csv</a> (MD5: 551431023f171cda91049d5cfba5f39e)</p>
<p><a href="soils.csv">soils.csv</a> (MD5: 4159cb47cb736980d6d27cf73681e678)</p>
</div><h2>Description</h2><div>
<p>Intensively managed grasslands are globally prominent ecosystems. We investigated whether experimental increases in plant diversity in intensively managed grassland communities can increase their resource use efficiency.
This work consisted of a coordinated, continental-scale 33-site experiment. The core design was 30 plots, representing 15 grassland communities at two seeding densities. The 15 communities were comprised of four monocultures (two grasses and two legumes) and 11 four-species mixtures that varied in the relative abundance of the four species at sowing. There were 1028 plots in the core experiment, with another 572 plots sown for additional treatments. Sites agreed a protocol and employed the same experimental methods with certain plot management factors, such as seeding rates and number of cuts, determined by local practice. The four species used at a site depended on geographical location, but the species were chosen according to four functional traits: a fast-establishing grass, a slow-establishing persistent grass, a fast-establishing legume, and a slow-establishing persistent legume. As the objective was to maximize yield for intensive grassland production, the species chosen were all high-yielding agronomic species.
The data set contains species-specific biomass measurements (yield per species and of weeds) for all harvests for up to four years at 33 sites. Samples of harvested vegetation were also analyzed for forage quality at 26 sites.
Analyses showed that the yield of the mixtures exceeded that of the average monoculture in >97% of comparisons. Mixture biomass also exceeded that of the best monoculture (transgressive overyielding) at about 60% of sites. There was also a positive relationship between the diversity of the communities and aboveground biomass that was consistent across sites and persisted for three years. Weed invasion in mixtures was very much less than that in monocultures.</p>
<p>These data should be of interest to ecologists studying relationships between diversity and ecosystem function and to agronomists interested in sustainable intensification. The large spatial scale of the sites provides opportunity for analyses across spatial (and temporal) scales. The database can also complement existing databases and meta-analyses on biodiversity–ecosystem function relationships in natural communities by focusing on those same relationships within intensively managed agricultural grasslands.</p>
<p><i>Key words</i>: <i>agricultural grasslands; biodiversity; ecosystem function; forage quality; mixtures; monocultures; overyielding; plant community; species biomass; yield.</i>
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