Understanding 20 years of vegetation change in grasslands by focusing on
changes in the cover of Sasa hayatae and Miscanthus
sinensis
Abstract
The impact of Cervus nippon browsing on vegetation in grasslands
in Japan has become pronounced. In obtaining useful information for the
management of grasslands affected by C. nippon browsing, we aimed
to evaluate vegetation changes caused by browsing on multiple axes based
on vegetation survey data from two time periods and to use UAV-mounted
LiDAR data to determine the distribution of indicator species of
vegetation change on an areal scale. The study area was approximately 23
ha around the Ochiai Pass in Higashi Iya Ochiai, Miyoshi City, Tokushima
Prefecture. A vegetation survey was conducted in 2022 at the same 35
sites as in 2002 to understand the changes in vegetation. The ordination
using nonmetric multidimensional scaling (NMDS) revealed that the
changes in the cover of Sasa hayatae and Miscanthus
sinensis and in the current cover of M. sinensis caused by the
changes affected the vegetation in the study area. NMDS revealed that
the entire study area is not changing along a single axis. The data
acquired by the UAV-mounted LiDAR were used to estimate the density of
S. hayatae and M. sinensis, which are indicators of
vegetation change, on an areal basis. A high correlation was determined
between the mean values of the reflected intensity at heights of
0.7–0.8 m for S. hayatae and 1.4–1.5 m for M. sinensis.
The methods used in this study were useful for monitoring spatial and
temporal changes in vegetation, and they could be applied to the
management of different types of grasslands.