Portail documentaire

Dépouillements

Flow regulation reduces native plant cover and facilitates exotic invasion in riparian wetlands / Jane A Catford in Journal of applied ecology, 48 ([01/01/2011]) 

Public Citation [article]  inJournal of applied ecology > 48 [01/01/2011] . - 432-442 Titre : Flow regulation reduces native plant cover and facilitates exotic invasion in riparian wetlands Type de document : Électronique Auteurs : Jane A Catford ; Barbara J Downes ; Christopher J Gippel ; Peter A Vesk Année de publication : 2011 Article en page(s) : 432-442 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Plantes subspontanées, naturalisées, envahissantes Résumé : 1. River regulation and exotic plant invasion threaten riverine ecosystems, and the two often co-occur. By altering water regimes, flow regulation can facilitate plant invasion by providing conditions that directly benefit invading species, or by reducing competition from native species unsuited to the modified conditions. Integrating water and weed management has the potential to limit riparian plant invasion and maximize the ecological benefit of environmental flows. 2. We surveyed plant communities and modelled flood histories of 24 riparian wetlands along the regulated River Murray, south-eastern Australia. There were no suitable control rivers, so we compared modelled pre- and post-regulation hydrological data to quantify hydrological change in the study wetlands. Regression analyses revealed relationships between hydrological modification and cover of native non-weed, native weed and exotic weed groups and 10 individual species. 3. Exotic cover was highest and native non-weed cover lowest in wetlands that had experienced the greatest change in hydrology – a reduction in peak flow. Native weeds did not respond to hydrological modification indicating that exotic species’ success was not reliant on their generalist characteristics. 4. By altering habitat filters, hydrological modification caused a decline in amphibious native non-weed species cover and simultaneously provided drier conditions that directly favoured the exotic species group dominated by terrestrial species. Exotic species were potentially further assisted by human-mediated dispersal. 5. Species and functional diversity was inversely related to exotic cover. By shifting the balance between native and exotic taxa and changing community functional composition, flow regulation may disrupt the ecological function and ecosystem services of floodplain wetlands. 6. Synthesis and applications. Worldwide, flow regulation has led to riverine ecosystems becoming more terrestrial. The success of most introduced plants relies on minimal inundation. In this study, flood magnitude was more important than frequency, timing, or duration for wetland flora because it reflects spatial extent and depth of flooding. Augmenting natural spring floods with environmental flows will kill terrestrial weeds and facilitate native macrophyte growth. Combined with strategies for managing particular amphibious weeds, we recommend flows of 117 000–147 000 ML day−1 for at least 2 days every 10 years for River Murray wetland weed management. Lien pérenne : DOI : 10.1111/j.1365-2664.2010.01945.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=142753 Catford, Jane A, Downes, Barbara J, Gippel, Christopher J, Vesk, Peter A 2011 Flow regulation reduces native plant cover and facilitates exotic invasion in riparian wetlands. Journal of applied ecology, 48: 432-442.

Documents numériques

Consultable Article (2011) URL

Clarifying climate change adaptation responses for scattered trees in modified landscapes / Martin F. Breed in Journal of applied ecology, 48 ([01/01/2011]) 

Public Citation [article]  inJournal of applied ecology > 48 [01/01/2011] . - 637-641 Titre : Clarifying climate change adaptation responses for scattered trees in modified landscapes Type de document : Imprimé Auteurs : Martin F. Breed ; Kym M. Ottewell ; Michael G. Gardner ; Andrew J. Lowe Année de publication : 2011 Article en page(s) : 637-641 Langues : Anglais (eng) Catégories : [LOTERRE-Biodiversité] Changement climatique [CBNPMP-Thématique] Conservation et gestion des espèces Résumé : 1. Many studies have investigated adaptation to climate change. However, the term ‘adaptation’ has been used ambiguously and sometimes included parts of both classic evolutionary processes and conservation planning measures (i.e. human-mediated adaptation). 2. To reduce ambiguity, we define three classes of evolutionary processes involved in adaptation – migrational, novel-variant and plasticity. Migrational adaptation describes the process of redistribution of standing genetic variation among populations. Novel-variant adaptation describes the increase in frequency of beneficial, new genetic variants. Plasticity adaptation refers to adaptive plastic responses of organisms to environmental stressors. Quite separately, human-mediated adaptation aims to maintain these evolutionary processes. 3. Whilst the role of scattered trees in migrational adaptation of fauna may have been neglected in the past, their capacity to assist migrational adaptation of trees has been previously documented. However, their role in novel-variant and plasticity adaptation is generally unrecognised, and warrants further attention. 4. Synthesis and applications. By defining different aspects of adaptation carefully, we show that scattered trees should not be cleared since they may facilitate gene flow across fragmented landscapes. However, they should be avoided as dominant seed sources since their stock may be of poor quality. Lien pérenne : DOI : 10.1111/j.1365-2664.2011.01969.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=149228 Breed, Martin F., Ottewell, Kym M., Gardner, Michael G., Lowe, Andrew J. 2011 Clarifying climate change adaptation responses for scattered trees in modified landscapes. Journal of applied ecology, 48: 637-641.

Documents numériques

Consultable Article (2011) URL