Invader complexes or generalist interactions? Seasonal effects of a disturbance gradient on plants and floral visitors
Invader complexes or generalist interactions? Seasonal effects of a disturbance gradient on plants and floral visitors
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DOI：
10.1016/j.foreco.2021.119963
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发表时间：
2021-12-23
影响因子：
3.7
通讯作者：
Garibaldi, Lucas A.
中科院分区：
文献类型：
--
作者：
Aguero, Juan, I;Coulin, Carolina;Garibaldi, Lucas A.
干扰可以促进外来植物的传播，外来植物与外来蜜蜂建立互惠关系，构成入侵者复合体。然而，干扰介导的花卉资源的增加也可以促进本地花卉访客，因为植物与传粉者的相互作用是多面性的。我们在巴塔哥尼亚北部的林地对这些想法进行了实验测试。在三个地点，我们研究了收获强度(生物质去除的0%、30%、50%、70%)对花卉密度(外来草本植物；本地：草本植物、灌木、乔木)和花卉访客密度(外来蜜蜂、大黄蜂；本地：蜜蜂和黄蜂、苍蝇、其他苍蝇、甲虫、蚂蚁)的影响。在四年的时间里，我们在整个花期进行了观察，以测试季节性。HI对本地草本植物的正向影响最大，其次是灌木，对乔木的正向影响为零。不同地点对外来草本植物花卉密度的影响不同。HI促进外来大黄蜂、本地蜜蜂和黄蜂、飞蝇的密度，但对蜜蜂无影响，对其他访花群体有不同程度的影响。尽管季节性是相关的，但与HI没有强烈的交互作用。总体而言，HI提高了本地和外来花卉访客的密度，这可以用通才相互作用而不是入侵者复合体来更好地解释。
Disturbances can facilitate the spread of exotic plants, which establish mutualisms with exotic bees, constituting invader complexes. However, a disturbance-mediated increase in flower resources can also promote native floral visitors due to the fact that plant-pollinator interactions are generalist. We experimentally tested these ideas in northern Patagonian woodlands. In three sites, we examined the effect of harvesting intensity (HI) (0%, 30%, 50%, 70% of biomass removal) on flower density (exotic: herbs; native: herbs, shrubs, trees) and floral visitor density (exotic: honey bees, bumblebees; native: bees and wasps, hoverflies, other flies, beetles, ants). For four years, we made observations throughout the flowering period to test seasonality. HI had the most substantial positive effect on native herbs, followed by shrubs, and it was null on trees. The effects on the floral density of exotic herbs depended on site. HI enhanced the density of exotic bumblebees, native bees and wasps, and hoverflies; but it had no effect on honey bees, and it showed variable effects on the other floral-visitor groups. Although seasonality was relevant, there was no strong interaction with HI. In general, HI enhanced the density of native and exotic floral visitors, which is better explained by generalist interactions rather than by invader complexes.