Role of environmental filtering and seed source availability in natural regeneration processes following large-scale disturbances in mountain forests

Jerzy Szwagrzyk,Elżbieta Muter,Kacper Foremnik,Antoni Zięba,Jan Bodziarczyk,Tomasz Zwijacz-Kozica,Barbara Ciesielska,Janusz Szewczyk,Anna Gazda

doi:10.1007/s10342-021-01371-2

Abstract

The relative importance of environmental factors and species pool in natural regeneration processes is still intensively disputed. Is environmental filtering especially important for species with higher requirements for temperature and soil fertility? Is the seed source limitation especially pronounced among tree species with lower dispersal abilities? Trees, seedlings and saplings measurements were conducted in 600 plots of 0.05 ha distributed in a regular grid in the Tatra Mountains (elevation range 817–1797 m a.s.l.). Boosted regression trees were used to analyse the relationships between the numbers of young trees, factors acting as environmental filters and the potential seed source availability. The most important factor affecting the distribution of young trees of most species was elevation; bedrock type was the second most important factor for Acer pseudoplatanus, while potential solar radiation was important for Sorbus aucuparia. The relationship between the presence of mature trees and abundance of young ones was strong in Fagus sylvatica, moderately strong in A. pseudoplatanus, and weak in Picea abies, Abies alba and S. aucuparia. The role of environmental factors in shaping the abundance of young trees varies strongly among species, while the seed source availability is very important for large-seeded trees.

Highlights

The relative roles of environmental factors and the presence of already established individuals in vegetation dynamics have been a matter of discussion in several recent papers (Burton et al 2011)
We focused upon comparisons between mature trees and tall saplings, which have already gone through the stage of high mortality and are quite likely to eventually replace the mature trees in the future
The density of natural regeneration recorded in this study was twice as high as the density found in naturally regenerated areas after windstorms in the Swiss Alps (Kramer et al 2014) and comparable to the densities of seedlings recorded after large-scale disturbances in the Slovakian part of the Tatra Mountains (Budzáková et al 2013)

Summary

Introduction

The relative roles of environmental factors and the presence of already established individuals in vegetation dynamics have been a matter of discussion in several recent papers (Burton et al 2011). The environmental factors act as filters, determining the possibility of a given species to become established and survive in certain habitats (Franklin et al 2013; Kraft et al 2015). In forest communities, the performance of plants growing on the forest floor is strongly affected by the tree canopy. After an intense disturbance and high mortality among mature trees, resources are released. By the time they are taken by the understory plants, they are available for the young trees. The environmental filtering effects in the case of young trees should be clearly visible (Laliberté et al 2014)

Methods

Results

Conclusion