Gallé Róbert, Tölgyesi Csaba, Szabó Ágota Réka, Korányi Dávid, Bátori Zoltán, Hábenczyus Alida, Török Edina, Révész Kitti, Torma Attila, Gallé-Szpisjak Nikolett, Lakatos Tamás, Batáry Péter
'Lendület' Landscape and Conservation Ecology, Institute of Ecology and Botany, Centre for Ecological Research, Alkotmány út 2-4, 2163 Vácrátót, Hungary; National Laboratory for Healty Security, Centre for Ecological Research, Alkotmány út 2-4, 2163 Vácrátót, Hungary; MTA-SZTE 'Momentum' Applied Ecology Research Group, Közép fasor 52, 6726 Szeged, Hungary.
MTA-SZTE 'Momentum' Applied Ecology Research Group, Közép fasor 52, 6726 Szeged, Hungary; Department of Ecology, University of Szeged, Közép fasor 52, 6726 Szeged, Hungary.
Sci Total Environ. 2023 Dec 10;903:166199. doi: 10.1016/j.scitotenv.2023.166199. Epub 2023 Aug 10.
Plant invasion and habitat fragmentation have a detrimental effect on biodiversity in nearly all types of ecosystems. We compared the direct and indirect effects of the invasion of the common milkweed (Asclepias syriaca) on biodiversity patterns in different-sized Hungarian forest-steppe fragments. We assessed vegetation structure, measured temperature and soil moisture, and studied organisms with different ecological roles in invaded and non-invaded sites of fragments: plants, bees, butterflies, flower-visiting wasps, flies, true bugs, and spiders. Temperature and soil moisture were lower in invaded than in non-invaded area. Milkweed had a positive effect on plant species richness and flower abundance. In contrast, we mainly found indirect effects of invasion on arthropods through alteration of physical habitat characteristics and food resources. Pollinators were positively affected by native flowers, thus, milkweed indirectly supported pollinators. Similarly, we found higher species richness of herbivores in invaded sites than control sites, as species richness of true bugs also increased with increasing plant species richness. Predators were positively affected by complex vegetation structure, higher soil moisture and lower temperature. Furthermore, increasing fragment size had a strong negative effect on spider species richness of non-invaded sites, but no effect in invaded sites. Especially, grassland specialist spiders were more sensitive to fragment size than generalists, whereas generalist spider species rather profited from invasion. Although milkweed invades natural areas, we did not identify strong negative effects of its presence on the diversity of the grassland biota. However, the supportive effect of milkweed on a few generalist species homogenises the communities. The rate of invasion might increase with increasing fragmentation, therefore we recommend eliminating invasive plants from small habitat fragments to preserve the native biota. Focusing also on generalist species and revealing the indirect effects of invasions are essential for understanding the invasion mechanisms and would support restoration efforts.
植物入侵和栖息地破碎化几乎对所有类型生态系统中的生物多样性都有不利影响。我们比较了普通马利筋（Asclepias syriaca）入侵对不同大小匈牙利森林草原片段生物多样性模式的直接和间接影响。我们评估了植被结构，测量了温度和土壤湿度，并研究了片段中入侵和未入侵地点具有不同生态作用的生物：植物、蜜蜂、蝴蝶、访花黄蜂、苍蝇、椿象和蜘蛛。入侵区域的温度和土壤湿度低于未入侵区域。马利筋对植物物种丰富度和花朵数量有积极影响。相比之下，我们主要发现入侵通过改变物理栖息地特征和食物资源对节肢动物产生间接影响。传粉者受到本地花朵的积极影响，因此，马利筋间接支持了传粉者。同样，我们发现入侵地点的食草动物物种丰富度高于对照地点，因为椿象的物种丰富度也随着植物物种丰富度的增加而增加。捕食者受到复杂植被结构、较高土壤湿度和较低温度的积极影响。此外，片段大小增加对未入侵地点的蜘蛛物种丰富度有强烈负面影响，但对入侵地点没有影响。特别是，草原特化蜘蛛比泛化蜘蛛对片段大小更敏感，而泛化蜘蛛物种则从入侵中获益更多。尽管马利筋入侵自然区域，但我们并未发现其存在对草原生物群落多样性有强烈负面影响。然而，马利筋对一些泛化物种的支持作用使群落同质化。随着破碎化加剧，入侵速度可能会增加，因此我们建议从小栖息地片段中清除入侵植物以保护本地生物群。关注泛化物种并揭示入侵的间接影响对于理解入侵机制至关重要，并将支持恢复工作。
