2024-06-25 カナダ・ブリティッシュコロンビア大学(UBC)
今年の蝶の目撃数が減少した理由として、湿った涼しい春と外来昆虫に対する農薬散布が考えられます。iNaturalistによれば、メトロバンクーバー地域での蝶の観察数は、4月から6月にかけて昨年の約1,000件から約400件に減少しました。
◆UBCのミシェル・ツェン助教授は、蝶の減少の原因として、春が例年より涼しく湿っていたことを挙げています。蝶は成虫になるために一定の温度が必要で、春が涼しいと成虫になるまでの時間が長くなります。また、雨天時には蝶は飛びたがらないため、観察数が減少します。さらに、外来種対策としての農薬散布も蝶に影響を与える可能性があります。
◆蝶は環境条件に敏感で、環境の変化の指標となるため、蝶の減少は重要な問題です。気候変動による異常気象も影響している可能性があります。
<関連情報>
- https://news.ubc.ca/2024/06/the-mystery-of-the-missing-butterflies-in-vancouver/
- https://cdnsciencepub.com/doi/full/10.1139/cjz-2023-0150
都市街路樹における鱗翅目種の豊かさと群集構成 Lepidoptera species richness and community composition in urban street trees
Risa Ogushi, Edward Sun, Leah R. E. Campbell, Fritzi B. Chandrakumar, Ray Fort, Nicole Graham, Julien Grebert, Orissa Grewal, …
Canadian Journal of Zoology Published:23 May 2024
DOI:https://doi.org/10.1139/cjz-2023-0150
Abstract
The triple threats of climate change, habitat loss, and environmental pollution have stimulated discussion on how urban areas can be modified to mitigate heat increases and provide habitat for wildlife such as insects. The strategy of using trees to reduce temperatures has been adopted by numerous cities. However, the majority of street trees planted around the world are non-native. Studies conducted in non-urban areas have demonstrated in comparison to native plants, non-native plants are less likely to support native insect diversity. Here, we use a database approach to quantify the number of native Lepidoptera species associated with 76 of the most common street tree species planted in Vancouver, Canada. We tested the prediction that compared to non-native trees, native street trees will support a higher diversity and unique community of native Lepidoptera. As predicted, native street trees were associated with five times as many native Lepidoptera species, and the Lepidoptera communities supported by native versus non-native street trees were distinct. There was no difference in native Lepidoptera associations between broadleaf versus coniferous street trees. These results are consistent with studies that have used active sampling techniques to investigate insect richness on a smaller subset of native and non-native tree species. Collectively, these data provide good evidence that planting native instead of non-native trees will help stem the loss of insect diversity in urban areas.
