Campos-Navarrete, M. J. | Search bioRxiv

bioRxiv2021

Effects of productive management of an agroforestry system on the associated diversity of parasitoids (Hymenoptera: Braconidae)

Tropical agroecosystems have emerged from the continuous modification of natural environments, as a sustainability alternative for food production and biodiversity conservation. This work explores how the diversity of parasitoids is modified in environments where plant diversity is limited e.g. crops and when these are adjacent to secondary vegetation, i.e. a scenario fragmented continuously in a limited space. It was found that there is no direct effect of plant diversity in the group of parasitoids studied; but the number of specialist species is high, which indicates that in diversified agroecosystems these probably function as remnants of natural habitat or as a refuge for parasitoids that disperse to different types of management within the agroecosystem. Therefore, it is necessary to consider in future studies the controls exerted by the plant diversity effects bottom-up and consumer top-down. Adding to this the context of the interactions that occur in agroecosystems.

ecology↗

bioRxiv2019

The effect of alien species on plant-pollinator network structure across a gradient of plant species invasion

The interactions between pairs of native and alien plants via shared use of pollinators have been widely studied. Studies of invasive species effects at the community level on the other hand are still scarce. Few community level studies, however, have considered how differences in the intensity of invasion, and degree of floral trait similarity between native and invasive species, can mediated effects on native plant-pollinator communities. Here, we evaluated the effect of alien species on overall plant-pollinator network structure, and species-level network parameters, across nine coastal communities distributed along 205 km at Yucatan, Mexico that vary in alien species richness and flower abundance. We further assessed the effect of alien plant species on plant-pollinator network structure and robustness via computational simulation of native and invasive plant extinction scenarios. We did not find significant differences between native and alien species in functional floral phenotypes, the visitation rate and species composition of the pollinator community. Variation in the proportion of alien plant species and flower abundance across sites did not affect plant-pollinator networks structure. Species-level network parameters (i.e., normalized degree and nestedness contribution) did not differ between native and alien species. Furthermore, our simulation analyses revealed that alien species are functionally equivalent to native species and contribute equally to network structure and robustness. Overall, our results suggest that alien species are well integrated into native coastal plant-pollinator networks which may be facilitated by high levels of floral trait similarity and pollinator use overlap. As a result, alien species may play a similar role than that of natives in the structure and stability of native plant and pollinator communities in the studied coastal sand dune ecosystem.

ecology↗