Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432, Aas, Norway.
Sci Rep. 2020 Oct 28;10(1):18485. doi: 10.1038/s41598-020-75723-0.
Predation of invertebrate pest by natural enemies is a critical contribution of nature to people, because invertebrate pests cause a vast amount of economic damage and pesticides use has many long-term costs. Veteran trees are keystone structures and hotspots for biodiversity, and are a potential source of natural enemies. To explore this, we used a balanced experimental design where we measured predatory beetle diversity and attack marks on three colors of artificial caterpillars placed around 20 veteran oaks and 20 nearby young oaks, in Southern Norway. We predicted that around the veteran oaks there would be a greater diversity of predatory beetles and more invertebrate attacks on artificial caterpillars. Sampling for predatory beetles was conducted in summer 2017 and 2018, and invertebrate attacks were measured in 2018. We found support for the predictions: diversity of predatory beetles was higher around veteran trees and there were more arthropod attack marks on artificial caterpillars placed around veteran trees. Our results indicated that veteran trees are a source of natural enemies. Valuing and protecting veteran trees and their communities is an essential step towards a more sustainable system of management that has the possibility of promoting both the wellbeing of people and biodiversity.
天敌捕食无脊椎害虫是大自然对人类的重要贡献，因为无脊椎害虫会造成巨大的经济损失，而农药的使用会带来许多长期的成本。古树是关键结构和生物多样性热点，也是天敌的潜在来源。为了探索这一点，我们使用了平衡实验设计，在挪威南部的 20 棵老橡树和 20 棵附近的年轻橡树周围，测量了三种颜色的人工毛毛虫上捕食性甲虫的多样性和攻击痕迹。我们预测，在老橡树周围会有更多种类的捕食性甲虫，以及更多的无脊椎动物攻击人工毛毛虫。2017 年和 2018 年夏季进行了捕食性甲虫的采样，2018 年测量了无脊椎动物的攻击。我们的研究结果支持了这些预测：老橡树周围的捕食性甲虫多样性更高，而且放在老橡树周围的人工毛毛虫上的节肢动物攻击痕迹也更多。我们的研究结果表明，古树是天敌的来源。重视和保护古树及其群落是建立更可持续的管理系统的重要步骤，这有可能促进人类福祉和生物多样性的共同发展。
