A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Effects of Goose Herbivory on Littoral Vegetation and Aquatic Macroinvertebrates During Breeding Season
Tekijät: Kjeller, Elsie; Arzel, Céline; Elmberg, Johan; Söderquist, Pär; Gunnarsson, Gunnar
Kustantaja: Wiley-Blackwell
Julkaisuvuosi: 2025
Lehti: Freshwater Biology
Artikkelin numero: e70114
Vuosikerta: 70
Numero: 10
ISSN: 0046-5070
eISSN: 1365-2427
DOI: https://doi.org/10.1111/fwb.70114
Julkaisun avoimuus kirjaamishetkellä: Avoimesti saatavilla
Julkaisukanavan avoimuus : Osittain avoin julkaisukanava
Verkko-osoite: https://doi.org/10.1111/fwb.70114
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/505835196
- During recent decades, increased populations of geese have raised concerns about their potential impact on the abundance and composition of shoreline vegetation through grazing, and how this may affect other organisms relying on the same vegetation for food or refuge.
- We investigated the direct effects of goose grazing on shoreline vegetation and the potential indirect effects on aquatic macroinvertebrates, assessed through an exclosure experiment. The study was carried out over one growing season (March–August) in ten eutrophic wetlands with varying goose density, all located in agricultural landscapes in southern Sweden. We predicted that exclosures protected from grazing would have higher vegetation aboveground biomass, height, cover and species diversity (H′), as well as greater macroinvertebrate total abundance, taxon richness and taxon diversity compared to control plots.
- Aboveground biomass was 27% higher in exclosures. However, goose density correlated positively with vegetation cover (%) and species diversity, but negatively with vegetation height. Aquatic macroinvertebrate total abundance was significantly lower in exclosures, whereas neither taxon richness nor diversity differed between controls and exclosures. Moreover, the total abundance of aquatic invertebrates was generally higher in wetlands with moderate goose density. No significant associations were found between goose density and taxon richness or diversity of macroinvertebrates.
- In conclusion, predictions regarding direct grazing effects on vegetation were confirmed only for aboveground biomass. However, in some sites, dense stands of reed and cattails may have reduced grazing pressure by physically restricting accessibility. Additionally, substantial differences in vegetation species composition among study sites contributed to high data variability, which potentially could have masked treatment effects.
- The results add to a growing number of studies suggesting that geese do not invariably cause or contribute to the degradation of aquatic ecosystems, at least in highly productive wetlands and when goose density is moderate. Our study highlights the need for more experiments investigating the grazing effects of large herbivorous waterbirds in aquatic ecosystems in different environmental settings. Identifying thresholds at which grazing effects begin to impact the ecosystem would provide a valuable tool for wildlife and wetland management.
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