Highlighting the importance of dispersal and establishment in vegetation dynamics and resilience

Prepared by Judit Sonkoly, James M. Bullock, Borja Jiménez-Alfaro & Péter Török

This blog post summarizes conclusions to the Special Feature “Dispersal and establishment”, edited by Péter Török, James M. Bullock, Borja Jiménez‐Alfaro and Judit Sonkoly (https://doi.org/10.1111/jvs.12958).

Investigating the dynamics that structure plant communities and consequently influence whole ecosystems is of crucial importance to understand the response of ecosystems to global change. Yet, we are still a long way from understanding the processes driving vegetation dynamics at different spatial and temporal scales. The two major features of plant communities that enable their stability are resistance and resilience in response to disturbances such as fires, floods, or over-grazing. Resistance is the ability of a community to maintain its structure and functions despite disturbances, while resilience is its ability to recover from changes induced by disturbance. Resilience depends on several processes, including dispersal of seeds and their survival in the soil (spatial seed dispersal and soil seed bank formation), and germination and establishment in favourable locations and vegetation gaps, as summarised in the schema below. In our rapidly changing world, it is vital to study how these processes jointly shape plant communities exposed to disturbances. Papers included in the recent special feature of the Journal of Vegetation Science entitled “Dispersal and establishment” deal with different aspects of dispersal and regeneration and how they affect vegetation dynamics in the face of natural or anthropogenic disturbances. In our editorial entitled “The importance of dispersal and species establishment in vegetation dynamics and resilience”, by reviewing contributions in this Special Feature, we drew general conclusions and outlined research gaps to be filled in the future.

The most important conclusion that can be drawn from the contributions in this Special Feature is that the processes of dispersal and establishment should not be simplistically considered as stochastic or random when studying vegetation dynamics.

We identified four specific research gaps that should be addressed by future studies:

1. The relationship between disturbances and microsite availability. – The creation of vegetation gaps induces vegetation changes via the establishment of species in the seed bank or in the seed rain, meaning that the composition of the seed bank and seed rain may be more important in disturbance-driven vegetation dynamics than that of the standing vegetation. However, species’ regeneration niches are considered much less in vegetation dynamics than the traits and environmental tolerances of adult plants.
2. The link between plant traits related to dispersal, seed bank formation and establishment. – Processes of dispersal and establishment should be included in the classic filter concept of community assembly, but for this, we need to focus more on traits related to these processes and not only on the traits of adult plants.
3. The landscape’s influence on spatial processes. – The effects of landscape-scale habitat configuration and diversity are considered much less in vegetation science than the effects of local factors. To address vegetation changes and biodiversity loss induced by the ongoing global change, metacommunity concepts need to be included more centrally in vegetation science.
4. The effects of humanity on vegetation dynamics. – Human influences are now inevitable in virtually every habitat, so understanding the effects of human-mediated dispersal, landscape degradation and fragmentation, altered disturbance regimes, and other anthropogenic processes on vegetation dynamics is vital to alleviate adverse human impacts.