Posted by Carolina Lara @carislaris

I was recently asked by an engineer friend of mine what my PhD project was about. In my (failed) attempt to put it into simple words, I ended up giving him a large discourse on the topic. A couple of days passed and he got back to me to say “… I always thought biological systems were simpler”. I am new to this world of ecological networks, but simplicity is not a word that can be used to describe them. More specifically for animal-plant mutualistic networks, a set of animals interacts mutualistically with a set of plants that are connected to another set of animals that interact with another set of plants. Animals disperse a plant´s genes and get food as a reward, as in the case of pollination and seed dispersal ecosystem services.

Kereru (Hemiphaga novaeseelandiae), New Zealand’s native pigeon, feeding on Nikau Palm (Rhopalostylis sapida) fruit

The dynamics of these networks and how they are built have profound implications on the coexistence of species and moreover, they can give us insights about how resilient they are to human disturbances, such as habitat fragmentation. It has now been recognised that conservation efforts should not only be directed to species alone, but should also be extended to the interactions and networks they form. Loss of interactions would translate into loss of ecological functions and this could happen even before actual species extinctions, a concept known as extinction debt of ecological interactions. Daniel Janzen, a pioneer scientist in tropical ecology, stated more than 40 years ago that “what escapes the eye, however, is a much more insidious kind of extinction: the extinction of ecological interactions”. So, we really are talking about complexity when we talk about networks. And I’m glad I changed my friend´s perception of just how complex biological systems are.

Carolina Lara M. is a PhD Candidate within the Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her research interests focus on seed dispersal networks within fragmented landscapes. She is supervised by Margaret Stanley, Jason Tylianakis, Karine David, and Anna Santure.