Importance of intraspecific variation and spatiotemporal turnover for forecasting plant-pollinator interactions under environmental change
Author(s)
Cantwell-Jones, Aoife
Type
Thesis
Abstract
Mutualisms represent a critical set of interactions globally, underpinning biodiversity and ecosystem stability. Thus, understanding the mechanisms structuring mutualistic interactions will be essential for forecasting how interactions will be affected by environmental change. In recent decades, using a trait-based approach to determine interaction probabilities between taxa has started to prove fruitful. However, when implemented, this approach has typically focused on interactions aggregated across landscapes and over years, failing to account for intraspecific variation in interactions and traits. Given interactions occur between individuals reacting to local environmental conditions, this aggregation risks obscuring the mechanisms underlying why individuals interact. In this thesis, I examine how incorporating intraspecific variation and the spatiotemporal context into plant-pollinator networks can move us towards a more predictive framework of their interactions. I use a montane Arctic bumblebee community as a case study, as this system captures a natural temperature gradient through an elevational cline, has a short growing season with rapid phenological turnover, and considerable intraspecific variation through bumblebee life history. I find bumblebee individuals across species can be more morphologically similar (in body size) than within species, and this trait overlap among species is important for providing redundancy against extinctions in the network. Bumblebees additionally exhibit a large seasonal trait turnover (decoupled from species turnover), which when not considered, can mislead us on the mechanisms underpinning plant-bumblebee interactions. Finally, I find that bee activity, interaction patterns and functional availability are structured by fine-scale temperature variation, with the scale at which we study climate (micro or macro) being important for our ability to detect these trends. Overall, my thesis underlines the necessity of incorporating intraspecific variation and spatiotemporal turnover into plant-pollinator networks for accurately understanding the processes underpinning them and for predicting how interactions will be reshaped under climate change.
Date Issued
2024-08-01
Date Awarded
2025-03-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Gill, Richard
Sponsor
Natural Environment Research Council
Grant Number
NE/S007415/1
Publisher Department
Department of Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)