Assessing How Understory Plant and Pollinator Interactions are Affected by Differing Canopy Phenologies

Abstract

Advancements in springtime phenologies of plants and their pollinators have been widely observed within the northern hemisphere due to climate change. The observed advancements have led to concern over potential mismatching occurring between plant-pollinator interactions. The effect of forest canopies on understory phenological interactions has scarcely been investigated. We studied the effect of differing canopy closure parameters on understory phenological interactions within Plymbridge woods, Devon, UK, over a 6-month study period. The temporal overlap between canopy, understory flower and pollinators were investigated using Pianka overlap indices. Canopy phenology was modelled using NLSTIMEDIST package of R, giving three canopy parameters, canopy r (maximum rate of canopy closure), canopy c (temporal concentration) and canopy t (canopy closure duration). All temporal overlap values were as expected within the woodland, suggesting no mismatching has occurred within the woodland to date. Supporting previous literature, suggesting plants and their pollinators are shifting phenologies at similar rates. Canopy r was seen to have a significant positive relationship with the overlap between canopy and understory flowers, suggesting as canopy closure rate increased, the temporal overlap between canopy and flowers also increased. However, Canopy c contradicted this with a negative relationship with the overlap between canopy and understory flowers. The discrepancies seen between these two canopy parameters are likely due to the low sample size due to limited resources within the study. Despite the low sample sizes within the study, the methodology used will likely be useful for future studies, investigating the effect of canopy closure on understory phenologies.