Regeneration: an overlooked aspect of trait‐based plant community assembly models

Abstract

1. Despite the disproportionate influence that propagule production, dispersal, seed-to-seedling recruitment and vegetative reproduction can have on plant population and community dynamics, progress has been slow in the directed collection of regeneration traits to inform community assembly outcomes. 2. While seed mass is globally available and linked to growth and reproductive output, there are limits to its explanatory ability. In this essay, we call for expanded efforts to integrate a more diverse set of regeneration traits into community assembly models. 3. First, we extend an existing community assembly framework to conceptualize regeneration as a series of transitional processes whose outcomes are influenced by abiotic filters, biotic interactions and species traits. We then briefly review the literature, highlighting filters and traits of demonstrated or theorized importance for each transition. Finally, we place regeneration in the context of existing and emerging modelling approaches in trait-based community assembly, summarizing key areas of progress needed to integrate regeneration traits into these efforts. 4. Synthesis. By incorporating influential regeneration traits into empirical studies and global data bases, we can begin to disentangle regenerative mechanisms underlying community assembly outcomes and enhance rapidly developing models of species' abundances, distributions and responses to environmental change.

Temperate rain forest species partition fine-scale gradients in light availability based on their leaf mass per area (LMA)

“…Few studies so far have incorporated functional traits of early-stage development plant organisms (e.g. saplings) into community assembly models (Larson and Funk, 2016). Specifically, we found that woody species partitioned fine-scale gradients in light availability based on their LMA, and this niche partitioning potentially facilitates species coexistence at the within-community level.…”

“…This finding provides evidence of trait-based partitioning of fine-scale light availability by woody species at the regeneration level. We also propose that the concept of resource-use strategy successfully applied to adults can be used to define the regeneration niche of plant species (see Larson and Funk, 2016). This trait-based niche partitioning of fine-scale light availability was not evident in the Mediterranean forest community we studied, where light is not expected to be limiting.…”

“…We concentrated on early life stages (i.e. saplings), because it is known that adaptations to the regeneration niche, encompassing the environmental conditions encountered in the early phases of a plant's life cycle, play a central role in coexistence of woody species (Grubb, 1977;Poorter, 2007), and also because regeneration traits in general have been much overlooked in the traitbased approach for community assembly models (Larson and Funk, 2016). We chose LMA -the leaf dry investment per unit of light-intercepting leaf area deployed (Poorter et al, 2009) -because it is a trait intimately related to light availability (and therefore carbon investment), reflecting different light acquisition strategies (Wright et al, 2004;Pérez-Harguindeguy et al, 2013).…”

Predicting the global incidence of seed desiccation sensitivity

“…Jiménez‐Alfaro et al . ; Larson & Funk ) in favour of functional traits measured solely for the mature plant and, more rarely, also for seedlings. One key seed trait that plays an important role in the regeneration ecology of a species is the ability of the seed to survive desiccation (Tweddle et al .…”

The functional trait spectrum of European temperate grasslands

“…Plant species may be particularly sensitive to environmental filtering at the regeneration stage and this might be more important than other life‐history stages as species could be totally excluded from a habitat due to inappropriate environmental conditions for germination or successful establishment (Grubb, ). However, our knowledge of plant trait ecology is largely focused on few traits concerning aboveground vegetative growth and morphology, and very few studies have assessed the potential role of regeneration traits (Jiménez‐Alfaro, Silveira, Fidelis, Poschlod, & Commander, ; Larson & Funk, ; Poschlod et al., ; Saatkamp et al., ). Regeneration traits have been long acknowledged as relevant to the natural maintenance of biodiversity (Grubb, ), and have been found to be important for both species coexistence and species sorting (Bernard‐Verdier et al., ; Fernández‐Pascual, Pérez‐Arcoiza, Prieto, & Díaz, ; Pierce, Bottinelli, Bassani, Ceriani, & Cerabolini, ).…”