Accounting for demographic uncertainty increases predictions for species coexistence: A case study with annual plants

Abstract

Natural systems contain more complexity than is accounted for in models of modern coexistence theory. Coexistence modelling often disregards variation arising from stochasticity in biological processes, heterogeneity among individuals and plasticity in trait values. However, these unaccounted-for sources of uncertainty are likely to be ecologically important and have the potential to impact estimates of coexistence. We applied a Bayesian modelling framework to data from an annual plant community in Western Australia to propagate uncertainty in coexistence outcomes using the invasion criterion and ratio of niche to fitness differences. We found accounting for this uncertainty altered predictions of coexistence versus competitive exclusion for 3 out of 14 species pairs and yielded a probability of priority effects for an additional species pair. The propagation of uncertainty arising from sources of biological complexity improves our ability to predict coexistence more accurately in natural systems.

Different measures of niche and fitness differences tell different tales

“…Fifth, if the method applies to a system, then the method should be easy to apply and require as few experiments as possible (Godwin et al 2020). Sixth, niche and fitness differences should be robust against measurement errors (Bowler et al 2022).…”

Building modern coexistence theory from the ground up: the role of community assembly

“…A better understanding of non-coexistence is direly needed, as often models fitted to empirical data predict competitive exclusion despite co-occurring species (Buche et al ., 2022; Germain et al ., 2016; Kraft et al ., 2015b; Godoy & Levine, 2014). This mismatch between empirical observation may stem from difficulties of assessing the actual underlying species interactions (Adler et al ., 2018a) or from uncertainties (Bowler et al ., 2022). However, it is also conceivable that non-coexistence is more than solely the absence of coexistence.…”

Pathways to global-change effects on biodiversity: new opportunities for dynamically forecasting demography and species interactions

“…Although the intrinsic relationship between demographic and community levels of organization has traditionally been well recognized [52][53][54][55][56], its integration to forecasting has remained elusive [57]. Prominent examples of multispecies demographic models exist in coexistence research [56,58], eco-evolutionary dynamics [59], trophic interactions [60,61] and forest stand dynamics [35]. However, forecasting applications that empirically assess the feedback between species demography and species interactions in a community context are largely missing (but see [35] for approaches to indirectly link demography and community composition via resources).…”