Oral Presentation Australian Freshwater Sciences Society Conference 2024

Testing a Method to Quantify Structural Redundancy in Ecological Communities. (113859)

David Dodemaide 1 , Galen Holt 1 , Rebecca E. Lester 1
  1. Centre for Regional and Rural Futures, Deakin University, Waurn Ponds, Victoria, Australia

In ecological communities, some taxa contribute to ecosystem functioning in highly similar ways. When numerous taxa within a community contribute similarly, this might suggest a degree of functional redundancy, where the loss of one species may not necessarily impair ecosystem functioning, providing other functionally similar species can compensate for the loss.

Multidimensional ordination is commonly used to analyse patterns in ecological communities over space and time, being most intuitively visualised using multidimensional scaling techniques. The patterns produced by these techniques can therefore be thought of as a community's structure. Research has shown that it is typical for multiple taxa in a community to contribute to this structure interchangeably therefore implying a different form of redundancy, structural redundancy, where only a small subset of taxa is required to recreate the overall community pattern. Further to this, there may in fact be multiple mutually exclusive subsets of taxa within a community that can reproduce the full-community pattern.

In this presentation, we will examine a method proposed to quantify the amount of structural redundancy within ecological communities and then explore potential links between structural redundancy and functional concepts, such as functional redundancy and compensation. Notionally, a high degree of structural redundancy has previously been indicative of a high potential for functional redundancy.

This concept had seldom been explored in the literature, and certainly not for freshwater macroinvertebrate communities. We performed a series of tests on multiple macroinvertebrate community data sets to discover what, if any, characteristics of a community would strongly influence the amount of structural redundancy present.Our tests ultimately determined that the analytical approach proposed to quantify the amount of structural redundancy is extremely sensitive to sample size. As such, we demonstrate that this approach is unable provide any reliable information regarding the potential for functional redundancy in ecological communities.