Nonnative Species in British Columbia Eelgrass Beds Spread via Shellfish Aquaculture and Stay for the Mild Climate

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• 作者：Megan E. Mach ; Colin D. Levings ; Kai M. A. Chan
• 关键词：British Columbia ; Seagrass ; Nonnative ; Invasive ; Exotic ; Aquaculture ; Zostera marina
• 刊名：Estuaries and Coasts
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：40
• 期：1
• 页码：187-199
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment, general; Ecology; Freshwater & Marine Ecology; Environmental Management; Coastal Sciences; Water and Health;
• 出版者：Springer US
• ISSN：1559-2731
• 卷排序：40

文摘

Nonnative species cause economic and ecological impacts in habitats they invade, but there is little information on how they spread and become abundant. This is especially true for nonnative species in native Zostera marina eelgrass beds in coastal British Columbia, Canada, which play a vital role in estuarine ecosystems. We tested how nonnative species richness and abundance were related to both arrival vectors and environmental factors in northeast Pacific eelgrass. Using correlation tests and generalized linear models, we examined how nonnative macroinvertebrates (benthic, epifaunal, and large mobile) and some algae species were related to arrival vectors (shipping and aquaculture) and environmental factors (climate variables, human population density, and native richness and abundance). We found 12 nonnative species, 50 % with known negative impacts within eelgrass habitats. For benthic organisms, both nonnative richness and abundance were strongly correlated with shellfish aquaculture activities, and not with shipping activity. For epifaunal nonnative richness and abundance, neither vector was significantly correlated. Climate (temperature and salinity) helped explain nonnative richness but not abundance; there was no relationship of nonnative richness or abundance to native species richness and abundance or population density. Results suggest that aquaculture activities are responsible for many primary introductions of benthic nonnative species, and that temperature and salinity tolerances are responsible for post-introduction invasion success. While aquaculture and shipping vectors are becoming increasingly regulated to prevent further international spread of nonnative species, it will be important when managing nonnatives to consider secondary spread from intraregional transport through local shellfish aquaculture and shipping.