Time filter

Source Type

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


Iijima H.,Yamanashi Forest Research Institute | Nagaike T.,Yamanashi Forest Research Institute | Honda T.,Yamanashi Prefecture Agricultural Research Center
Journal of Wildlife Management | Year: 2013

Deer population control is important in wildlife management, because overabundance of deer is a problem worldwide. For practical deer population control, deer population dynamics and the factors that influence them need to be evaluated in low-cost and time-efficient ways. However, in traditional methods of estimation, such as cohort analysis, large numbers of deer need to be caught for many years, and the ages of the deer must be determined. We estimated deer population dynamics by using a Bayesian state-space model with multiple deer abundance indices (seen deer per unit effort, pellet group count, and block count) and numbers of deer hunted and culled in Yamanashi Prefecture, central Japan. In the state process of our state-space model, latent deer abundance at year t in location m (Dt,m), with m being each cell of a grid mesh covering Yamanashi Prefecture, was assumed to decrease annually through hunting and culling, to increase with the population growth rate of each mesh (r m; which was determined from the percentages of forest, evergreen forest, and artificial grassland), and to fluctuate stochastically. In the observation process, Dt,m was assumed to be correlated with the deer abundance indices and a Gaussian white noise in the deer abundance indices. The estimated Dt,m was correlated with each deer abundance index, but the correlation coefficient was the greatest for pellet group density. The percentage of hunted and culled deer needed to reach 30% to reduce the annual growth rate (Dt,m/Dt-1,m). Increasing the percentage of artificial grassland increased rm. Our results showed that 1) deer abundance could be estimated by using only deer abundance indices in addition to population growth rate and the percentage of hunted and culled deer; and 2) preventing the intrusion of deer onto artificial grassland and intensive culling on artificial grassland were important to decrease deer abundance. © 2013 The Wildlife Society.


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.


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.


Goto S.,Tokyo University of Science | Iijima H.,Hokkaido University | Iijima H.,Yamanashi Forest Research Institute | Ogawa H.,Hokkaido University | Ohya K.,Hokkaido University
Restoration Ecology | Year: 2011

To evaluate the effects of intraspecific hybridization of local and nonlocal genotypes on growth traits of progeny in Abies sachalinensis, we performed reciprocal crossing between nonlocal trees in a high-elevation zone (1,100-1,200 m asl) and local trees in a low-elevation zone (530 m asl) in Hokkaido, northern Japan, in 1979 and established a common garden experiment using local × local (female × male), local × nonlocal , nonlocal × local , and nonlocal × nonlocal progeny in the low-elevation zone in 1986. Survival, height, diameter at breast height (dbh), needle nitrogen content, specific leaf area (SLA), and needle area per shoot diameter (NA) of 25-year-old progeny were measured in 2005. The survival rate was consistently high (>85% on average). Reductions in height and dbh were apparent in F1 hybrids compared with local × local progeny. Furthermore, outbreeding depression was significant in height growth of nonlocal × local F1 hybrids and in dbh of both F1 hybrids. Reductions in growth traits may be related to morphological needle traits, such as the low values of SLA and NA. Elevation guidelines for A. sachalinensis seed zones are discussed to ensure the long-term viability of both restored and native populations. © 2009 Society for Ecological Restoration International.


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.


Iijima H.,Yamanashi Forest Research Institute | Nagaike T.,Yamanashi Forest Research Institute
Ecological Indicators | Year: 2014

Increasing deer density can cause serious degradation of forests in the Americas, Europe, and Asia. To manage deer impacts, evaluating their current impacts on forest ecosystems is necessary, usually via vegetation indices. However, the relationship between vegetation indices and absolute deer density, while taking into account tree size, snow depth, light condition, and the type of understory vegetation, has never been investigated. We examined the relationship between various vegetation indices and absolute deer density in 344 study plots in the deciduous broad-leaved forest of Yamanashi Prefecture, central Japan. In each plot, debarking and browsing, along with the coverage and maximum height of understory vegetation, were surveyed. Estimated deer densities for 82 5 × 5-km mesh units ranged from 0.8 deer/km2 to 32.7 deer/km2. The percentages of debarked trees within a plot ranged from 0 to 84%. Debarking was promoted by high deer density, small tree size, and thick snow. The effect of tree size on debarking was stronger than that of deer density. Occurrence of browsing on understory vegetation was higher at higher deer densities, and where understory vegetation was dominated by evergreen dwarf bamboo. Coverage and maximum height of understory vegetation were unaffected by deer density but increased with canopy openness and the dominance of dwarf bamboo in the understory. Overall, we predict that debarking of small trees living in heavy snow areas should occur even at low deer densities (<10 deer/km2). Browsing on dwarf bamboo should occur at intermediate deer densities (10-30 deer/km2), while debarking of thick trees living in low snow areas should occur only at high deer densities (≥30 deer/km2). Our study shows that debarking and browsing on understory vegetation are appropriate indices for evaluating deer impacts on forest ecosystems, but that tree size, snow depth, and the type of understory vegetation should also be considered. © 2014 Elsevier Ltd. All rights reserved.


Nagaike T.,Yamanashi Forest Research Institute | Nagaike T.,University of Tokyo
Journal of Forest Research | Year: 2010

Species composition and community structure of naturally regenerated trees in Larix kaempferi plantations and natural forests were compared in relation to altitudinal gradient. Fifty-nine L. kaempferi plantations and 26 natural forest stands including old-growth and secondary forests were selected from 1300 to 2000 m a. s. l. in Mt Kushigata of central Japan. Vegetation plots (10 × 10 m) were established in each stand (85 plots in total). Species composition differed significantly between forest types, particularly on high altitude plots. Some species were significantly biased to natural forests, while no species were biased to plantations. Although some species that responded significantly to altitude were common to both forest types (e.g., Acer ukurunduese, Castanea crenata, and Fraxinus lanuginose f. serrata), some differed between forest types (e.g., Fagus japonica, Prunus maximowiczii, and P. nipponica). Thus, plantation management altered species responses to altitude. Altitude should be considered when planning and carrying out forest ecological restoration in plantations, because species composition of naturally regenerated trees has already been changed by past plantation management. In particular, attention should be paid to ecological restoration at high altitude. © The Japanese Forest Society and Springer 2009.


Nagaike T.,Yamanashi Forest Research Institute
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2014

Forest certification schemes have had a pivotal role in conserving biological diversity and enhancing ecosystem services in the field of sustainable forest management. This review has shown an increasing trend in forest certification research. In particular, the effects of forest certification on biological diversity and the natural environment were summarized, and future research directions were discussed. The number of research articles focusing on certification has sharply increased in foreign scientific journals, and many have focused on objective comparisons of certification programs. Only a few articles directly evaluated the conservation of rare and threatened species in certified forests. Many such articles indirectly showed the possibility of conserving these species through improvements in forest management practices via certification (e.g., preserving riparian areas in the case of logging). However, some authors assert that certification is of little value in minimizing the negative impacts of forestry, and that it does not play an important role in conserving biological diversity outside of nature reserves which were designated by laws. Research should be conducted to quantitatively analyze the impacts of certification on biological diversity conservation, and to evaluate outcomes of forest certification schemes on site. Certification plays an important role in promoting the integration of social and natural sciences within the field of forest science, and any research relating to it should be encouraged.

Loading Yamanashi Forest Research Institute collaborators
Loading Yamanashi Forest Research Institute collaborators