Red de Ecoetología, Instituto de Ecología A.C., Carretera antigua a Coatepec 351, Colonia El Haya, Xalapa, Veracruz 91073, Mexico.
Centro Tlaxcala de Biología de la Conducta (CTBC), Universidad Autónoma de Tlaxcala, Tlaxcala 90000, Mexico.
Sci Total Environ. 2024 Dec 1;954:176553. doi: 10.1016/j.scitotenv.2024.176553. Epub 2024 Sep 29.
Urbanization is a significant driver of land use change, profoundly impacting biodiversity and ecosystem services worldwide. However, its effects in the tropics, which host some of the planet's highest biodiversity, remain inadequately understood. Orchid bees (Apidae: Euglossini) are key pollinators in Neotropical ecosystems, playing crucial roles in maintaining floral diversity and reproductive success of orchids and other plant families. Yet, little is known about how urbanization influences their diversity and pollination. In this study, we analyzed the diversity and composition or orchid bee communities along an urbanization gradient which extends from the city center to the surrounding cloud forests, which bear high orchid endemism while being highly threatened. Along the same gradient, we further evaluated pollination of a model native orchid, Gongora galeata, which is exclusively pollinated by the bee Euglossa obrima. As expected, increasing urbanization led to a decrease in orchid bee diversity, as well as a clear separation in species composition between urban and non-urban sites and a reduction in G. galeata pollination (i.e. fruit production). However, contrary to our expectations, orchid pollination also decreased with environmental heterogeneity and the abundance of its specific pollinator. Despite urban areas still hosting orchid bee species, our results reveal clear negative effects of urbanization not only on diversity, but also on the ecosystem function of a highly threatened group of bees. This study highlights the importance of considering local factors of urban landscapes for preserving not only biodiversity, but also fundamental ecological processes in cities.
城市化是土地利用变化的重要驱动因素，深刻影响着全球的生物多样性和生态系统服务。然而，城市化对热带地区的影响，这些地区拥有地球上一些最高的生物多样性，仍未得到充分理解。兰花蜂（Apidae: Euglossini）是新热带生态系统中的关键传粉者，在维持兰花和其他植物科的花卉多样性和繁殖成功方面发挥着至关重要的作用。然而，人们对城市化如何影响它们的多样性和传粉知之甚少。在这项研究中，我们分析了兰花蜂群落的多样性和组成，沿着一个城市化梯度延伸，从市中心到周围的云雾森林，这些森林承载着高兰花特有种，同时也受到高度威胁。沿着同一梯度，我们进一步评估了模型本地兰花 Gongora galeata 的传粉情况，该兰花仅由蜜蜂 Euglossa obrima 传粉。正如预期的那样，随着城市化的加剧，兰花蜂的多样性减少，城市和非城市地区的物种组成明显分离，以及 G. galeata 的传粉（即果实产量）减少。然而，与我们的预期相反，兰花的传粉也随着环境异质性和其特定传粉者的丰度而减少。尽管城市地区仍有兰花蜂物种，但我们的结果显示，城市化不仅对多样性，而且对高度受威胁的蜜蜂群体的生态系统功能都有明显的负面影响。这项研究强调了考虑城市景观的本地因素对于保护生物多样性以及城市中基本生态过程的重要性。
