Effects of sika deer (Cervus nippon) and dwarf bamboo (Sasamorpha borealis) on seedling emergence and survival in cool-temperate mixed forests in the Kyushu Mountains

Abstract

Effects of sika deer (Cervus nippon) and dwarf bamboo (''sasa;'' Sasamorpha borealis) on seedling emergence and survival were investigated in cool-temperate mixed forests in the Kyushu mountain range, Japan. We compared the effects of sika deer between two sites with different sika deer densities. One site (no-sasa forest) has sparse cover of S. borealis and a high density of sika deer, and the other site (sasa forest) has dense cover of S. borealis with a low density of sika deer. In the no-sasa forest, more seedlings emerged and the survival rate of the seedlings was higher compared with the sasa forest. Compared with the sasa forest, the canopy in the no-sasa forest was more open, the organic layer was shallower and drier, the mean daily soil temperature was higher, and soil temperature fluctuated more widely. Those environmental parameters did not differ between unfenced and fenced plots. The comparison between the sasa and no-sasa forests suggested that removal of S. borealis by sika deer had an indirect positive effect on seedling emergence and survival. However, the fenced-plot experiments indicated that sika deer inhibited seedling emergence and survival. These contradictory conclusions could result from the much larger negative effects of S. borealis on seedling emergence and survival compared with the effects of sika deer browsing.Keywords Cervus nippon density Á Direct and indirect effects of sika deer Á Exclosure experiment Á Regeneration Á Seedling emergence and survival

Influence of using texture information in remote sensed data on the accuracy of forest type classification at different levels of spatial resolution

“…and Tsuga sieboldii Carr., and deciduous broadleaved trees such as Quercus crispula Blume, Fagus crenata Blume and Acer sieboldianum Miq. (Murata et al 2009). …”

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Contribution of conspecific negative density dependence to species diversity is increasing towards low environmental limitation in Japanese forests

“…Generally, the effect of CNDD is the strongest for the smallest trees 20,29 , although trees with DBH ≥ 4.8 cm were recorded and analysed in our dataset. On the other hand, by not including the smallest trees we avoid the effect of overgrazing by deer, which has been a major problem preventing tree recruitment in Japan, especially in recent years 64 .…”

Effects of deer abundance on broad-leaf tree seedling establishment in the understory of Abies sachalinensis plantations

“…In addition to browsing, the canopy structure of overstory trees has a significant effect on seedling density (Tremblay et al 2007;Gill and Morgan 2010). Dwarf bamboo also often has a large effect on seedling density in Japanese forests (Nakashizuka 1987;Itô and Hino 2004;Murata et al 2009). Our study corroborates the findings of these earlier works (Table 4); seedling density was very low in some plots, even with low deer abundance (Fig.…”

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