Changes in understory species occurrence of a secondary broadleaved forest after mass mortality of oak trees under deer foraging pressure

Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Hokkaido, Japan
DOI
10.7287/peerj.preprints.2271v1
Subject Areas
Biodiversity, Ecology, Plant Science
Keywords
Japanese oak wilt, deer-unpalatable plant species, gap, understory vegetation, sika deer
Copyright
© 2016 Itô
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Itô H. 2016. Changes in understory species occurrence of a secondary broadleaved forest after mass mortality of oak trees under deer foraging pressure. PeerJ Preprints 4:e2271v1

Abstract

The epidemic of mass mortality of oak trees has affected secondary deciduous broadleaved forests that have been used as coppices in Japan. The dieback of oak trees formed gaps in the crown that would be expected to enhance the regeneration of shade-intolerant pioneer species. However, foraging by sika deer Cervus nippon has also affected forest vegetation, and the compound effects of both on forest regeneration should be considered when they simultaneously occur. A field study was conducted in Kyôto City, Japan, to investigate how these compound effects affected the vegetation of the understory layer of such a forest. The presence/absence of seedlings and saplings was observed for 200 quadrats sized 5 m × 5 m for each species in 1992, before the mass mortality and deer encroachment, and in 2014 after these effects. A hierarchical Bayesian model was constructed to explain the occurrence, survival, and colonization of each species with their responses to the gaps created or affected by the mass mortality of oak trees. The species that occurred most frequently in 1992, Eurya japonica, Quercus glauca, and Cleyera japonica, also had the highest survival probability. Deer-unpalatable species such as Symplocos prunifolia and Triadica sebifera had higher colonization rates in the gaps, while the deer-palatable species Aucuba japonica had the smallest survival probability. The gaps thus resulted in promoting the colonization of deer-unpalatable plant species such as Symplocos prunifolia and Triadica sebifera. It might be forecasted that such deer-unpalatable species will dominate the gaps created or affected by the mass mortality of oak trees.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Raw data of species presence/absence and quadrat attributes

R dump file containing raw data, y1: species presence (1) / absence (0) for each quadrat in 1992, y2: species presence (1) /absence (0) for each quadrat in 2014, plot: quadrat attributes (position: 0 for lower slope, 1 for upper slope, slope: slope angles (degree), affect: 0 for not gaps, 1 for gaps created or affected by the mass mortality). Vectors adj, weights and num are spatial data for OpenBUGS.

DOI: 10.7287/peerj.preprints.2271v1/supp-1

BUGS code used in the analysis

BUGS code used in the analysis.

DOI: 10.7287/peerj.preprints.2271v1/supp-2

Table of random species effects

Posterior mean, standard deviation (SD) and quantiles (2.5%, 5%, 50%, 95% and 97.5%) for each random species effect

DOI: 10.7287/peerj.preprints.2271v1/supp-3