2023-07-06 ワシントン州立大学(WSU)
◆この結果は、さらに破壊的なクアッガ貝とゼブラ貝による将来の侵入について懸念があることを示しています。コロンビア川はこれまでにこれらの侵略的な生物を免れていましたが、タイワンシジミの存在は深刻な問題であり、河川の清浄を維持するためには注意が必要です。
◆他の地域ではさらに多くのタイワンシジミが見つかっており、クアッガ貝とゼブラ貝も同様に問題となっています。人間の活動によってこれらの侵略的な生物が広がることがありますので、予防策や対策が重要です。
＜関連情報＞
- https://news.wsu.edu/press-release/2023/07/06/asian-clams-spread-in-columbia-river-warns-of-worse-invaders/
- https://onlinelibrary.wiley.com/doi/full/10.1002/iroh.202202134
米国コロンビア川下流域における侵略的タイワンシジミ（Corbicula fluminea）の広範な分布、存在量、生息地の関連性 Broadscale distribution, abundance, and habitat associations of the invasive Asian clam (Corbicula fluminea) in the lower Columbia River, USA
Salvador B. Robb-Chavez, Stephen M. Bollens, Gretchen Rollwagen-Bollens, Timothy D. Counihan
International Review of Hydrobiology Published: 27 May 2023
DOI:https://doi.org/10.1002/iroh.202202134
Abstract
The Asian clam, Corbicula fluminea, is an invasive freshwater bivalve that has established populations across the globe and is known to have deleterious effects on natural and human systems. Yet, despite being present in the Columbia River (CR) for nearly a century, little is known about this invader’s basic biology and ecology in this large river system. Thus, we undertook a field study to assess its (i) broadscale distribution and abundance, and (ii) associations with habitat characteristics in the lower CR. During 2019–2020, C. fluminea were collected from 27 shore-based stations spanning 481 river kilometers of the lower CR, along with several habitat characteristics (bank slope, temperature, dissolved oxygen, pH, salinity, conductivity, chlorophyll-a concentration, and sediment composition and % organic matter [OM]). C. fluminea abundance ranged from 0 to 430 ind. m−2. Most sites with abundances >100 ind. m−2 were located downstream of Bonneville Dam, whereas most sites with abundances <100 ind. m−2 were located upstream. Generalized linear models predicting the abundance of C. fluminea indicated significantly positive correlations with water temperature and % sand, and negative correlations with bank slope and sedimentary % OM. We also reviewed the global literature on abundance and habitat associations of C. fluminea and compared this with our own results. Our investigation represents the greatest spatial extent at which C. fluminea has been studied in the CR and our results provide a better understanding of the basic biology and ecology of this global invader, as well as provide natural resource managers with information on habitat conditions favorable for this invasive bivalve within temperate river ecosystems.
