How exotic plants integrate into pollination networks

1. There is increasing world-wide concern about the impact of the introduction of exotic species on ecological communities. Since many exotic plants depend on native pollinators to successfully establish, it is of paramount importance that we understand precisely how exotic species integrate into existing plant–pollinator communities. 2. In this manuscript, we have studied a global data base of empirical pollination networks to determine whether community, network, species or interaction characteristics can help identify invaded communities. 3. We found that a limited number of community and network properties showed significant differences across the empirical data sets – namely networks with exotic plants present are characterized by greater total, plant and pollinator richness, as well as higher values of relative nestedness. 4. We also observed significant differences in terms of the pollinators that interact with the exotic plants. In particular, we found that specialist pollinators that are also weak contributors to community nestedness are far more likely to interact with exotic plants than would be expected by chance alone. 5. Synthesis. By virtue of their interactions, it appears that exotic plants may provide a key service to a community’s specialist pollinators as well as fill otherwise vacant ‘coevolutionary niches’

Native and alien flower visitors differ in partner fidelity and network integration

<div><div>These data files support the following publication</div><div><br></div><div>Trøjelsgaard, K., Heleno, R., & Traveset, A. <b>Native and alien flower visitors differ in partner fidelity and network integration</b>. Ecology Letters, <i>accepted. </i>doi: 10.1111/ele.13287</div><div><i><br></i></div><div>For more details see the Read Me file or the original publication.</div></div><div><br></div><div><b><u>Abstract</u></b></div><div>Globalisation persistently fuels the establishment of non-native species outside their natural ranges. While alien plants have been intensively studied little is known about alien flower visitors, and especially, how they integrate into natural communities. Here we focus on mutualistic networks from five Galápagos islands to quantify whether alien and native flower visitors differ consistently in their pairwise interactions. We find that i) alien flower visitors have more interaction partners and larger species strengths (i.e. plants are more connected to alien insects), ii) native insects tend to have higher partner fidelity as they deviate more from random partner utilization, and iii) the difference between native and alien flower visitors in network integration intensifies with island degradation. Thus, native and alien flower visitors are not interchangeable, and alien establishment might have yet unforeseen consequences for the pairwise dynamics between plants and flower visitors on the Galápagos – especially on the heavily disturbed islands. <br></div