| 1. |
- Bommarco, Riccardo
(författare)
-
Landscape context and habitat type as drivers of bee diversity in European annual crops
- 2009
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 133, s. 40-47
-
Tidskriftsartikel (refereegranskat)abstract
- To better understand the dynamics of bee populations in crops, we assessed the effect of landscape context and habitat type on bee communities in annual entomophilous crops in Europe. We quantified bee communities in five pairs of crop-country: buckwheat in Poland, cantaloupe in France, field beans in the UK, spring oilseed rape in Sweden, and strawberries in Germany. For each country, 7-10 study fields were sampled over a gradient of increasing proportion of semi-natural habitats in the surrounding landscape. The CORINE land cover classification was used to characterize the landscape over a 3 km radius around each study field and we used multivariate and regression analyses to quantify the impact of landscape features on bee abundance and diversity at the sub-generic taxonomic level. Neither overall wild bee abundance nor diversity, taken as the number of sub-genera. was significantly affected by the proportion of semi-natural habitat. Therefore, we used the most precise level of the CORINE classification to examine the possible links between specific landscape features and wild bee communities. Bee community composition fell into three distinct groups across Europe: group I included Poland, Germany, and Sweden, group 2 the UK, and group 3 France. Among all three groups, wild bee abundance and sub-generic diversity were affected by 17 landscape elements including some semi-natural habitats (e.g., transitional wood land-shrub), some urban habitats (e.g., sport and leisure facilities) and some crop habitats (e.g., non-irrigated arable land). Some bee taxa were positively affected by urban habitats only, others by semi-natural habitats only, and others by a combination of semi-natural, urban and crop habitats. Bee sub-genera favoured by urban and crop habitats were more resistant to landscape change than those favoured only by semi-natural habitats. In agroecosystems, the agricultural intensification defined as the loss of semi-natural habitats does not necessarily cause a decline in evenness at the local level, but can change community composition towards a bee fauna dominated by common taxa. (C) 2009 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Farahbakhshazad, Neda, et al.
(författare)
-
Modeling biogeochemical impacts of alternative management practices for a row-crop field in Iowa
- 2008
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 123:1-3, s. 30-48
-
Tidskriftsartikel (refereegranskat)abstract
- The management of contemporary agriculture is rapidly shifting from single-goal to multi-goal strategies. The bottleneck of implementing the strategies is the capacity of predicting the simultaneous impacts of change in management practices on agricultural production, soil and water resources and environmental safety. Process-based models provide an opportunity to quantify the impacts of farm management options on various pools and fluxes of carbon (C) and nitrogen (N) in agroecosystems. The denitrification-decomposition or DNDC model was recently modified for simulating N cycling for the U.S. Midwestern agricultural systems. This paper reports a continuous effort on applying the model for estimating the impacts of alternative management practices (e.g., no-till, cover crop, change in fertilizer rate or timing) on agroecosystems in the Midwestern U.S. A typical row-crop field in Iowa was selected for the sensitivity tests. The modeled results were assessed with a focus on four major indicators of agro-ecosystems, namely crop yield, soil organic carbon (SOC) sequestration, nitrate-N leaching loss and nitrous oxide (N2O) emissions. The results indicated that no-till practice significantly increased SOC storage and reduced nitrate-N leaching rate, but slightly decreased crop yield and increased N2O emissions. By modifying the methods of fertilizer application in conjunction with the no-till practice, the disadvantages of no-till could be overcome. For example, increasing the fertilizing depth and using a nitrification inhibitor could substantially reduce N2O emissions and increase crop yield under the no-till conditions. This study revealed the complexity of impacts of the alternative farming management practices across different climate conditions, soil properties and management regimes. Process-based models can play an important role in quantifying the comprehensive effects of management alternatives on agricultural production and the environment.
|
|
| 3. |
- Gustafson, G.M., et al.
(författare)
-
Barn balance calculations of Ca, Cu, K, Mg, Mn, N, P, S and Zn in a conventional and organic dairy farm in Sweden
- 2007
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 119:1-2, s. 160-170
-
Tidskriftsartikel (refereegranskat)abstract
- Calculations of flows and balances of plant nutrients in agricultural production systems provide some basic information for the assessment of their long-term sustainability. The objectives of this study were to assess the possible impacts of variations in element concentrations between years and of undefined sinks and sources of elements on the accuracy of balance calculations. A 3-year study was conducted on Ca, Cu, K, Mg, Mn, N, P, S, and Zn fluxes in the barns (subsystem) of a Swedish farm with separate conventional and organic milk production. Our main focus in this subproject was on barn balance calculations, the barn housing only cows. Barn balance for an element was defined as amount of that element in [feeds, heifers, bedding, water] - [milk, manure, urine, calves, culled cows]. The focus was on: (1) variations in element concentrations in the main flow carriers [feeds, milk, manure, urine]; (2) information about element dynamics and flows of dairy farming systems obtained from internal flows of elements in the barn balance compared with that obtained from the flows associated with milk production in a farm gate balance; (3) differences in element flows and concentrations between the organic and conventional farming systems on this farm. Our conclusions were: (1) the sampling methods used had low coefficients of variation and thus pooled samples can reduce the costs of element analyses. However, urine must be thoroughly mixed if less water-soluble elements are to be monitored. Magnesium differed significantly in concentrations between years in all feedstuffs; (2) year-to-year fluctuations in harvest can influence a calculation negatively if calculations are based on annual harvest and not on feed supplied. The barn balance calculation showed a source of Cu, Mn and Zn that would not have been obvious in a farm gate balance. The element content of manure and urine calculated as [inputs - milk] would have underestimated the amount of Cu, Mn and Zn in manure and overestimated the amount of K and N. The Cu analysis showed an example of conflicting goals between short-term welfare of the cows and long-term soil fertility. EU legislation regarding land for spreading of manure is not a guarantee against soil contamination by heavy metals; (3) the differences between the organic and conventional system related more to differences in forage: concentrate and home-grown: purchased ratios, which were typical for the average Swedish farm of each type, and less to differences in element concentrations of the feed ingredients. © 2006 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Manderscheid, Remy, et al.
(författare)
-
Glufosinate treatment of weeds results in ammonia emission by plants
- 2005
-
Ingår i: Agriculture, Ecosystems & Environment. - Amsterdam : Elsevier. - 0167-8809 .- 1873-2305. ; 109:1-2, s. 129-140
-
Tidskriftsartikel (refereegranskat)abstract
- The herbicide glufosinate, which is also called phosphinothricin (PPT), is known to inhibit glutamine synthetase and thus causes a blockage of ammonium (re)assimilation in plants. The objective of the present study was to test whether application of this herbicide results in an ammonia volatilization from the plants and to quantify nitrogen loss via ammonia emission. Four different weed species (Chenopodium album, Echinocloa crus-galli, Solanum nigrum, Tripleurospermum inodorum) were grown as monocultures in the greenhouse and treated with PPT when their canopies covered the soil. In the first experiment, whole shoot samples were taken during the following days and analysed for ammonium, pH and total nitrogen content. In the second experiment, apoplastic pH and ammonium concentration of the leaves were measured after herbicide application and used for the calculation of Γ-values (ratio between NH4+ and H+ concentration), the stomatal NH3 compensation point and the canopy net NH3 flux with a soil vegetation atmosphere transport (SVAT) model.Herbicide treatment caused a rapid increase in shoot ammonium concentration and the ammonium portion of the plant total nitrogen ranged from 0.6 to 0.9% and from 17 to 44% before and after PPT application, respectively. S. nigrum showed a strong increase in ammonium portion (35%) followed by a decrease (20%), which may have resulted from ammonia volatilization. The difference in total shoot nitrogen content per ground area at the start and 2 weeks after PPT application averaged for the three C3 weed species to a nitrogen loss of ca. 0.4 g N m−2 or approximately 13% of the total nitrogen in the weed canopy. Analysis of the apoplastic fluid yielded an increase in ammonium concentration and a pH decrease after an initial increase on day 1 after the PPT treatment. In order to evaluate the potential for ammonia loss, the Γ-value was calculated for both apoplastic and tissue water. S. nigrum showed the most dramatic increases in both apoplastic and tissue–water Γ-values 4 days after PPT treatment. The calculated stomatal NH3 compensation point was strongly elevated after PPT treatment. However, temporal changes of apoplastic pH and ammonium concentration varied between the species and the modelled ammonia emission ranged from 0.03 to 0.09 g N m−2. It is concluded that PPT application results in an ammonia emission of ca.
|
|
| 5. |
- Ottvall, Richard, et al.
(författare)
-
Effects of an agri-environmental scheme on wader populations of coastal meadows of southern Sweden
- 2006
-
Ingår i: Agriculture, Ecosystems & Environment. - Amsterdam : Elsevier. - 0167-8809 .- 1873-2305. ; 113:1-4, s. 264-271
-
Tidskriftsartikel (refereegranskat)abstract
- Survey data on breeding wader densities and grazing intensity on coastal meadows on the Baltic island of Öland from 1988, 1998 and 2003 were used to evaluate density and density-changes of four common and widespread wader species, lapwing Vanellus vanellus, redshank Tringa totanus, oystercatcher Haematopus ostralegus and ringed plover Charadrius hiaticula in relation to grazing intensity. Population trends over time and changes in densities in relation to changes in grazing management were evaluated. Both wader densities and the environmental variable grazing intensity demonstrated significant spatial autocorrelation, but all main results were unaffected when accounting for spatial structure in the statistical tests. Breeding densities of investigated species were positively related to grazing intensity and local changes in grazing management affected the local change in wader densities. However, average grazing intensity increased over time whereas wader numbers generally remained constant or declined. Thus, changes in grazing intensity could not explain changes in overall breeding numbers. One explanation for this is probably that grazing mainly affected distribution of birds. Some evidence of a buffer effect was found in the redshank and ringed plover, in which breeding densities declined proportionally more in non-shore than in shore habitat. This was probably due to a redistribution of birds to shore habitat. It is concluded that grazing management is essential for the occurrence of waders, but might not be sufficient to ensure long-term viability of wader populations on coastal meadows.
|
|
| 6. |
- Salomon, Eva, et al.
(författare)
-
Outdoor pig fattening at two Swedish organic farms-Spatial and temporal load of nutrients and potential environmental impact
- 2007
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 121:4, s. 407-418
-
Tidskriftsartikel (refereegranskat)abstract
- In Sweden, outdoor organic pig production is gaining interest. However, the excretory behaviour of pigs may create plant nutrient hotspots in outdoor areas, increasing the environmental impact. This study examined fluxes and balances of N, P, K, Cu and Zn at pen level, and determined the effects of the excretory behaviour of fattening pigs on nutrient load, manure distribution and N, P, K, Cu and Zn concentration in soil within pens at two farms with different outdoor systems (mobile and stationary). A pen in the mobile system had about 72 pigs ha-1 and in the stationary system about 91 pigs ha-1. The average pen balance in the mobile system was 270 kg N, 60 kg P, 110 kg K, 0.4 kg Cu and 1.3 kg Zn ha-1 and in the stationary system 205 kg N, 57 kg P, 99 kg K, 0.4 kg Cu and 1.5 kg Zn ha-1. The smaller net accumulation of nutrients in the stationary system was due to about 30% of excrement nutrients being excreted indoors. A substantial proportion of nutrients (43-95%) from one pig group was found to be concentrated in an area of arable land representing 4-24% of the total pen area. In the mobile system the major part of the defecating was deposited on the hut, feeding and drinking sub-areas. The manure mapping also revealed pig behaviour of avoiding defecation in certain zones. In the stationary system, the concentration of exchangeable P and K in soil (0-30 cm depth) in areas preferred for excretion was more than four-fold higher and the concentration of mineral-N (0-90 cm depth) was about eight-fold higher than in other areas of the pen by the end of the fattening period. Preferred areas for excretion within the pen were affected both by the present pig groups and by previous pig groups 4 years back in time. In the mobile system, the concentration of mineral-N in soil was about three-fold higher in preferred excretion areas compared with other areas. Neither of the two outdoor systems succeeded in avoiding excessive point loads of N within the pen. The flexibility of the mobile outdoor system has to be further improved so that no harmful point loads of nutrients can occur. In the stationary system, a nutrient management technique for collecting the manure on the preferred excretion areas on arable land needs to be developed. © 2006 Elsevier B.V. All rights reserved.
|
|
| 7. |
- Öster, Mathias, et al.
(författare)
-
Plant colonization of ex-arable fields from adjacent species-rich grasslands : the importance of dispersal vs. recruitment ability
- 2009
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 130:3-4, s. 93-99
-
Tidskriftsartikel (refereegranskat)abstract
- Species-rich semi-natural grasslands have declined drastically in Europe over the last century and occur in modern landscapes as small and isolated fragments. Recreation of these species-rich plant communities and increasing connectivity of remaining grasslands are important goals for nature conservation. Ex-arable fields located adjacent to species-rich grasslands have been suggested as targets for such recreation, but we still lack knowledge about the processes determining colonization from grasslands to ex-arable fields. We examined transects from species-rich semi-natural grasslands to ex-arable fields in a nature reserve located in southeast Sweden, and analysed relationships between observed colonization of ex-arable fields and two characteristics of species: dispersal ability and recruitment ability. Colonization of ex-arable fields was not related to dispersal ability, assessed as adhesive potential to animal coat, wind dispersal potential and seed mass (related to seed production), but was positively related to recruitment ability, assessed by sowing experiment. The same relationships appeared when using a performance index from sowing experiments conducted in the UK. We conclude that recruitment ability is a key factor for colonization of ex-arable fields. In our study, around 50% of semi-natural grassland species were able to colonize adjacent ex-arable field margins spontaneously within a time window of less than 50 years. Seed sowing is however needed to increase the speed of the colonization process, because increasing seed density promotes colonization of species with poor recruitment in ex-arable fields. Actions to increase area and connectivity of species-rich grasslands should consider incorporating ex-arable fields.
|
|
| 8. |
- Öster, Mathias, et al.
(författare)
-
Validation of plant diversity indicators in semi-natural grasslands
- 2008
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 125:1-4, s. 65-72
-
Tidskriftsartikel (refereegranskat)abstract
- The use of plant biodiversity indicators in a nationwide survey of semi-natural grasslands in Sweden was examined by comparing results from the survey with additional in-depth studies of plant diversity at the same 30 sites in southern Sweden. Additional grasslands, that were not subjected to the nationwide survey (i.e. rejected after an initial site selection), were also investigated in order to examine the quality of the initial site selection and to assess to what extent they harboured species rich plant communities. Results showed that grasslands that were not included in the nationwide survey were generally smaller in size and that they contained significantly lower plant diversity than sites that were included by the survey. However, some indicator species, including indicators for poor management, were abundant in both types of sites. Biodiversity indicators correctly indicated both plant species richness and plant species density when using data from the in-depth study. However, by comparing indicator species found by the nationwide survey and by the in-depth study, it was shown that the survey overlooked 42% of all indicator species occurrences, which removed the significant relationship between indicator richness and total plant species richness. Furthermore, a null model showed that the chosen indicator species did not perform significantly better than species chosen at random from the available species pool. The conclusion was that validation of indicators is crucial, because even though real correlations exist between taxa or between a subset of species and overall diversity, poor precision of surveys might make these indicators useless. This also suggests that the effort put into searching for the indicator species may have to be so high, that it may be more efficient to go directly into assessing the biological values they are supposed to indicate.
|
|
| 9. |
|
|
| 10. |
- Lindborg, Regina, et al.
(författare)
-
A landscape perspective on conservation of semi-natural grasslands.
- 2008
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809. ; 125:1-4, s. 213-222
-
Tidskriftsartikel (refereegranskat)abstract
- Current agri-environmental schemes and subsidies for conservation and restoration of semi-natural grasslands do not explicitly assess land use changes affecting whole landscapes, but have so far focused on single objects and small areas. In this paper, we discuss a landscape perspective versus a “single object” perspective when conserving semi-natural grassland in agricultural landscapes. The focus is on the values biodiversity, cultural heritage, a vital countryside, and effects on economy when land use changes. We conclude that when land use change in the landscape surrounding an object, important additional effects on the different values are found. For example, a countryside where animals graze former arable fields and where marginal habitats are managed will have a positive effect, not only on the biodiversity associated to semi-natural grasslands, but also for the image of a vital and dynamic landscape. An increased number of roads, on the other hand, may negatively affect cultural heritage and decrease biodiversity in grasslands, leading to negative effects on the value of common goods through isolation. Placing objects in a larger spatial context and combining several different aspects into a landscape perspective, will improve long-term preservation of values associated to semi-natural grasslands.
|
|
