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How effective are European agri-environment schemes in conserving and promoting biodiversity ? / David Kleijn in Journal of applied ecology, 40 ([01/01/2003]) 

Public Citation [article]  inJournal of applied ecology > 40 [01/01/2003] . - 947-969 Titre : How effective are European agri-environment schemes in conserving and promoting biodiversity ? Type de document : Imprimé Auteurs : David Kleijn ; Willliam J. Sutherland (1956-) Année de publication : 2003 Article en page(s) : 947-969 Langues : Français (fre) Résumé : Increasing concern over the environmental impact of agriculture in Europe has led to the introduction of agri-environment schemes. These schemes compensate farmers financially for any loss of income associated with measures that aim to benefit the environment or biodiversity. There are currently agri-environment schemes in 26 out of 44 European countries. Agri-environment schemes vary markedly between countries even within the European Union. The main objectives include reducing nutrient and pesticide emissions, protecting biodiversity, restoring landscapes and preventing rural depopulation. In virtually all countries the uptake of schemes is highest in areas of extensive agriculture where biodiversity is still relatively high and lowest in intensively farmed areas where biodiversity is low. Approximately $24·3 billion has been spent on agri-environment schemes in the European Union (EU) since 1994, an unknown proportion of it on schemes with biodiversity conservation aims. We carried out a comprehensive search for studies that test the effectiveness of agri-environment schemes in published papers or reports. Only 62 evaluation studies were found originating from just five EU countries and Switzerland (5). Indeed 76% of the studies were from the Netherlands and the United Kingdom, where until In the majority of studies, the research design was inadequate to assess reliably the effectiveness of the schemes. Thirty-one percent did not contain a statistical analysis. Where an experimental approach was used, designs were usually weak and biased towards giving a favourable result. The commonest experimental design (37% of the studies) was a comparison of biodiversity in agri-environment schemes and control areas. However, there is a risk of bias if either farmers or scheme co-ordinators select the sites for agri-environment schemes. In such cases the sites are likely to have a higher biodiversity at the outset compared to the controls. This problem may be addressed by collecting baseline data (34% of studies), comparing trends (32%) or changes (26%) in biodiversity between areas with and without schemes or by pairing scheme and control sites that experience similar environmental conditions (16%). 5. Overall, 54% of the examined species (groups) demonstrated increases and 6% decreases in species richness or abundance compared with controls. Seventeen percent showed increases for some species and decreases for other species, while 23% showed no change at all in response to agri-environment schemes. The response varied between taxa. Of 19 studies examining the response of birds that included a statistical analysis, four showed significant increases in species richness or abundance, two showed decreases and nine showed both increases and decreases. Comparative figures for 20 arthropod studies yielded 11 studies that showed an increase in species richness or abundance, no study showed a decrease and three showed both increases and decreases. Fourteen plant studies yielded six studies that showed increases in species richness or abundance, two showed decreases and no study showed both increases and decreases. Synthesis and applications. The lack of robust evaluation studies does not allow a general judgement of the effectiveness of European agri-environment schemes. We suggest that in the future, ecological evaluations must become an integral part of any scheme, including the collection of baseline data, the random placement of scheme and control sites in areas with similar initial conditions, and sufficient replication. Results of these studies should be collected and disseminated more widely, in order to identify the approaches and prescriptions that best deliver biodiversity enhancement and value for money from community support." Lien pérenne : DOI : 10.1111/j.1365-2664.2003.00868.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=147261 Kleijn, David, Sutherland, Willliam J. (1956-) 2003 How effective are European agri-environment schemes in conserving and promoting biodiversity ? Journal of applied ecology, 40: 947-969.

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Consultable Article (2003) URL

Plant traits as predictors of performance in ecological restoration / Richard F. Pywell in Journal of applied ecology, 40 ([01/01/2003]) 

Public Citation [article]  inJournal of applied ecology > 40 [01/01/2003] . - 65-77 Titre : Plant traits as predictors of performance in ecological restoration Type de document : Imprimé Auteurs : Richard F. Pywell ; James Bullock ; David Roy ; Liz Warman ; Kevin John Walker ; Peter Rothery Année de publication : 2003 Article en page(s) : 65-77 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Restauration des écosystèmes [CBNPMP-Thématique] Revégétalisation Résumé : 1 There are few studies of the performance of species in restored vegetation communities. Here we report the results of a meta-analysis of 25 experiments concerned with species-rich grassland restoration on ex-arable land and agriculturally improved grasslands situated at a wide range of locations throughout lowland Britain. Differences in species’ performance were related to 38 physiological and morphological traits. 2 An experiment-adjusted performance index was calculated for each of the 58 species (13 grasses and 45 forbs). The performance index was calculated for the first 4 years after establishment together with a temporal trend. 3 Individual species showed large differences in performance indices. However, grasses consistently out-performed forbs. 4 We examined the linkage between species’ performance and traits according to four non-exclusive hypotheses. The ability to establish and persist in restored vegetation communities requires: (H1) good gap colonization ability; (H2) strong competitive capability; and (H3) ability to undergo vegetative regeneration. (H4) Successful species are generalists associated with fertile habitats. 5 Trait analyses supported all four hypotheses. Within the forbs, good establishment in the first year was linked to traits determining colonization ability: ruderality, percentage germination of seeds and autumn germination. However, traits linked to competitive ability, vegetative growth and seed bank persistence became increasingly important determinants of success with time. Species with generalist habitat requirements, and especially those associated with fertile soils, performed increasingly well with time. This reflects the development of a closed vegetation in which the ability to grow vigorously and out-compete other established plants is important. 6 Stress-tolerators, habitat specialists and species of infertile habitats performed badly. This may reflect high residual fertility in restored grasslands and particular niche requirements of these species. This may be a problem as grassland restoration often targets communities characterized by species with these traits and many are food plants of invertebrates of conservation value. 7 There were few significant correlations between the performance of the grasses and traits reflecting their overall good performance in comparison with the forbs. 8 This study has important implications for practical restoration programmes and policies. Efficiency might be increased by introducing only species with good performance, but this would lead to uniformity among restored grasslands and would diminish the benefits of habitat restoration for national and regional biodiversity. 9 Synthesis and applications. Future work should focus on practical methods to increase the successful establishment of the poor performing but desirable species, by (i) targeting restoration to low fertility soils, (ii) changing the abiotic environment or (iii) the ‘phased introduction’ of species several years after restoration, when both the plant community is more stable and the environmental conditions are more favourable for establishment. Note de contenu : Lien pérenne : DOI : 10.1046/j.1365-2664.2003.00762.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=148808 Pywell, Richard F., Bullock, James, Roy, David, Warman, Liz, Walker, Kevin John, Rothery, Peter 2003 Plant traits as predictors of performance in ecological restoration. Journal of applied ecology, 40: 65-77.

Documents numériques

Consultable Article (2003) URL