I’m currently a PhD candidate at the Experimental Plant Ecology Group at Radboud University, Nijmegen. My research focuses on the interaction between plant and pollinator communities – and more importantly, how information from emerging plant-pollinator interaction networks can be used to inform conservation/restoration projects in an era of insect declines.
Before we jump right into my research, let’s first have a look at plant-pollinator interaction networks – what are they and why study them? Plant-pollinator interaction networks consist of all species of the flower community on one side and all species of the pollinator community on the other. Each species is known as a ‘node’ and is depicted by a circle or square. The size of this node scales with its abundance – the more abundant a species is, the bigger the node that represents it will be. Now these species of course interact with each other and each recorded interaction (in this case a flower visitation event) is depicted as a line between the two interacting species (or nodes). The more interactions between two species, the larger the connection will become. Below, you can see an example from Roberto Novella-Fernandez et al. (2019).
Figure from Roberto Novella-Fernandez et al. (2019). An example of a plant-pollinator interaction network. Note how every block (=node) represents a species, and block size differs based on species abundance. The nodes are connected by species interactions and the size of the connection depends on the amount of interactions.
Now at first (or maybe after some time still) this might look confusing. But let’s take a step back and start simple; if bees would not visit flowers, they would not be pollinated. Vice versa, bees need to visit flowers for their food supply. Simple, right? As such, this network of interactions between species directly depicts ecosystem functioning! Rather than ‘just’ looking at the biodiversity of species and their abundance, we can see who is interacting with who. And that is what fascinates me so much about this field of research; we actually get to understand how multiple species can live together in the same area!
So what can we learn from these networks? First of all, theoretical studies have found that network properties can be linked to community diversity and stability. For instance, nested network organisation was linked to pollinator diversity and certain species within networks (so called hub-species) seem crucial for network stability by supporting many species and individuals. If some plant communities, through plant-pollinator interaction networks, are indeed better at supporting pollinators than others this is crucial information for pollinator restoration projects. However, how important are these networks for pollinator biodiversity in a field situation, where many more factors influence pollinators?
This is the central question in my research. By constructing plant-pollinator networks along a local and landscape level habitat gradient I study how local vegetation and landscape level factors (such as floral resource availability and surrounding habitat types) influence pollinator communities. By doing so I hope to identify factors that are crucial for pollinator community formation and thus future restoration projects. More specifically, I’m interested in the role of total plant diversity and specific plant (hub-)species in shaping pollinator communities. As pollinator restoration projects often aim at improving local plant communities this information could benefit these projects.