Honda T.,Yamanashi Prefecture Agricultural Research Center |
Iijima H.,Yamanashi Forest Research Institute
Population Ecology | Year: 2016
Wildlife can cause serious crop damages, and factorial analyses focusing ecological aspects have been conducted to resolve this problem. However, ethological perspectives should also be considered. Individuals often show consistent biases in behaviour—so-called personality; e.g., boldness may cause to intrude into a farmland. Here, we hypothesized that boldness–shyness traits in wildlife could be managed through selective harvesting on the base of personality traits. We considered several scenarios involving the selective harvesting and fencing as means to prevent crop damage, and assessed their effects on the average boldness and population size using simulation models, assuming that bold individuals tend to enter farmlands, while shy ones prefer to stay in forests. The results showed that fencing and selective harvesting in farmlands reduced both the average boldness and crop damages, while harvesting in forests caused the increase of the both. Those results came from the selective harvesting and fencing on the base of personality traits, and indicate that not only population ecology but also an ethological approach is needed for wildlife management. © 2016 The Society of Population Ecology and Springer Japan
Ohsawa M.,Yamanashi Forest Research Institute
Journal of Insect Conservation | Year: 2010
The conservation of biodiversity is an important goal of most forest management efforts, and proper monitoring of biodiversity requires immediate attention. Coleoptera, the largest order of organisms on Earth, should be monitored as a crucial part of overall biodiversity. To facilitate monitoring of Coleopteran diversity, indicators at the family level that adequately represent the beetle diversity were investigated. One Malaise trap was placed in each of 52 forest stands in the central mountainous region of Japan; all captured beetles were identified to species. Pearson's correlation coefficients were calculated between the number of species in each family and the total number of species in all families combined. The relationship between the species composition of each family and the overall composition of all families was examined using Mantel tests. Families with high correlation coefficients for species richness included Cerambycidae, Cleridae, Curculionidae, Lycidae, Elateridae. Families exhibiting strong similarity in composition to the composition of all families were Scolytidae, Elateridae, Curculionidae, Cerambycidae, and Staphylinidae and the Cerambycidae, Curculionidae, and Elateridae were determined to be useful surrogates for Coleopteran diversity. All significant pairwise correlations between each of these three families and other Coleopteran families were positive, indicating that each was appropriate as a competent surrogate. Thus, this study identified adequate diversity indicators in Coleoptera that can be caught by Malaise traps. The accumulation of data on indicators obtained through different methods or in different climates is necessary to ensure the selection of widely applicable indicator families as stable surrogates of beetle diversity. © 2010 Springer Science+Business Media B.V.
Nagaike T.,Yamanashi Forest Research Institute |
Nagaike T.,Yamanashi Comprehensive Research Organization for Science and Technology
Ecological Research | Year: 2012
The effects of browsing by sika deer (Cervus nippon) on subalpine vegetation (Betula forests and tall grasslands) were investigated in the South Alps National Park, Japan. The browsing ratio (the number of browsed quadrats to the number of quadrats occurring in each plot) was significantly higher in Betula forests than in grasslands. A significant negative correlation was found between the browsing ratio and some species diversity indices (number of species and the Shannon-Wiener diversity index) in the Betula forests, but not in grasslands. The frequency of occurrence and the number of preferred browse species were significantly higher in Betula forests than in grasslands. Browsing was not always the most serious on the most frequent vegetation. For example, Polemonium caeruleum L. subsp. yezoense var. nipponicum, which is listed as vulnerable on Japan's red list of threatened species and was low in occurrence in Betula forests compared to grasslands, was more browsed in Betula forests than in grasslands. Less frequently occurring species subjected to more browsing could easily disappear. The disappearance of such species would exert a strong effect on the species pool in the area. © 2012 The Ecological Society of Japan.
Nagaike T.,Yamanashi Forest Research Institute
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2012
This paper discusses the pros and cons, effects on productivity and their mechanisms, and other issues related to mixed tree plantations as an alternative to pure tree plantations. Mixed tree plantations provide a broad range of goods and ecosystem services via the diversity of species planted. This diversity provides various habitats and ecological niches and can improve productivity through reduced competition and facilitation. Issues involved in experimental mixed plantations include the spacing and distribution of species and trees. Most previous studies have focused on young plantations. Because management practices need to vary according to the objectives of a mixed tree plantation, many issues need to be resolved for the practical introduction of mixed tree plantations.
Ohsawa M.,Yamanashi Forest Research Institute |
Shimokawa T.,Yamanashi University
Biological Conservation | Year: 2011
We studied the effects of extending the rotation period (long-rotation) and related ecological variables on the biodiversity of six beetle families in larch (Larix kaempferi) plantations. Beetle diversity in the forest understory and the canopy of long-rotation and middle-aged plantations was compared. The relationships between the species richness of each beetle family and 24 ecological variables were identified. We found that beetle diversity tended to increase with long-rotation and responded differently to the ecological variables in two woodland strata (understory and canopy); e.g., an increase in phytophagies occurred in the canopy. Among the 24 measured ecological variables, the species richness of naturally regenerated mature trees, their abundance, and the quality and quantity of coarse woody material (CWM) had the strongest influences on beetle diversity. The former two variables increased with long-rotation; however, most variables related to CWM did not increase because thinned trees were left in middle-aged plantations as fallen logs. Therefore, the occurrence of naturally regenerated native trees that had grown sufficiently tall to reach canopy height in long-rotation plantations underpinned the improved biodiversity in larch plantations, contributing to native beetle species richness in these woodlands. Long-rotation makes plantations more heterogeneous, particularly in the canopy, and promotes greater native beetle diversity. © 2011 Elsevier Ltd.