Stand Composition, Tree-Related Microhabitats and Birds—A Network of Relationships in a Managed Forest

Jan Holeksa,Łukasz Piechnik,Mateusz Ledwoń,Grażyna Szarek-Łukaszewska,Magdalena Żywiec,Przemysław Kurek

doi:10.3390/f13010103

Abstract

Forest ecosystems contain many tree-related microhabitats (TreMs), which are used by various groups of organisms. Birds use TreMs for shelter, foraging and breeding. The abundance and variability of TreMs is related to tree stand composition and age. Over the last few centuries there has been a drastic decline in the structural and biological diversity of temperate forests over large areas of the Northern Hemisphere. These changes have reduced the diversity and quantity of TreMs. In this study we showed the relationships between stand composition, the abundance of TreMs, and the species richness of birds in a managed forest. We focused on TreMs that are important to birds: woodpecker breeding cavities, rot holes, dead branches, broken treetops, and perennial polypores. Our study was performed in a managed lowland temperate forest. In 94 plots (10 ha each) we made bird surveys and inventoried the stand composition and TreMs. Our results show that the tree stand composition of a managed forest affects the abundance of TreMs. The share of deciduous trees in the stand favors the occurrence of such TreMs as dead branches, rot holes and perennial polypores. The overall richness of bird species and the species richness of primary cavity nesters depended on the total basal area of oak, hornbeam and birch, whereas the species richness of secondary cavity nesters increased with the total basal area of birch and oak.

Highlights

Forest ecosystems contain many specific tree-related microhabitats; examples include tree hollows, necroses, rotted places on trunks, stem shoots, bark cracks, dead canopy branches or upturned root plates [1,2]
We focused on five tree-related microhabitats (TreMs) potentially related to birds and frequently present in managed forests: woodpecker breeding cavities, rot holes, dead branches, broken treetops and perennial polypores
TreMs were distributed non-randomly among tree species, we focused our analyses of bird assemblages on tree species composition

Summary

Introduction

Forest ecosystems contain many specific tree-related microhabitats (hereafter TreMs); examples include tree hollows, necroses, rotted places on trunks, stem shoots, bark cracks, dead canopy branches or upturned root plates [1,2]. The abundance of TreMs is positively related to the diversity of some species of vascular plants [3], fungi [4], invertebrates [5] and vertebrates [6,7] They are key structures for biodiversity in both managed and protected forests [8,9]. Woodpecker breeding cavities, which are breeding sites for both primary and secondary cavity nesters, are among the most-studied TreMs [9] Rot holes are another TreM well-known in the context of their relationship with birds. They arise as a result of mechanical damage and fungal activity, and serve as breeding places for secondary cavity nesters [13,14]. The significance of numerous other TreMs (e.g., dead branches, perennial polypores, broken treetops, trunk cracks) has not been studied in detail, but potentially they positively affect bird abundance

Methods

Results

Conclusion