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Fukasawa K.,Japan National Institute of Environmental Studies | Hashimoto T.,Japan Wildlife Research Center | Abe S.,Naha Nature Conservation Office
Journal of Applied Ecology | Year: 2013

Summary: An understanding of the underlying processes and comprehensive history of invasive species is necessary to assess the long-term effectiveness of invasive species management. However, continuous, long-term labour-intensive population surveys on invasive species are often not feasible. Thus, it is important to learn about their dynamics through management action and its consequences.  Amami Island, Japan, has an ongoing large-scale and long-term eradication programme of invasive small Indian mongooses. To estimate the long-term pattern of population size and the parameters determining the dynamics, including anthropogenic removal, we applied a surplus-production model within a Bayesian state-space formulation incorporating the initial population size, number of captures and capture effort. Using the estimated process model directly, we conducted stochastic simulations to evaluate the feasibility of eradication.  Estimated 32-year annual capture probability of mongooses has increased since their introduction. The population size started to decline in 2001; mean population size in 2000 was 6141 (95% CI: 5415-6817), and declined to 169 (95% CI: 42-408) by 2011. Parameter estimates of a Weibull catchability model indicated that there was large individual heterogeneity in the probability of being captured, and per-effort capture probability declined with an increase in annual capture effort.  The simulation study indicated that the eradication feasibility in 2023 would be over 90% if the same annual capture effort is upheld as in 2010 (2 075 760 corrected trap-days). However, increasing annual capture effort would have little effect on shortening the time to eradication.  Synthesis and applications. A hierarchical model that incorporates multiple types of data to reveal long-term population dynamics has the potential to be updated with the outcomes of control efforts, and will enhance adaptive management of invasive species. This approach will offer valuable information about trade-offs between time to eradication success and effort per unit time in a long-term eradication project, and the length of time needed to continue management actions to achieve eradication success. A hierarchical model that incorporates multiple types of data to reveal long-term population dynamics has the potential to be updated with the outcomes of control efforts, and will enhance adaptive management of invasive species. This approach will offer valuable information about trade-offs between time to eradication success and effort per unit time in a long-term eradication project, and the length of time needed to continue management actions to achieve eradication success. © 2013 British Ecological Society.


Yasukochi Y.,Graduate University for Advanced Studies | Kurosaki T.,Japan Wildlife Research Center | Yoneda M.,Japan Wildlife Research Center | Koike H.,Kyushu University | Satta Y.,Graduate University for Advanced Studies
BMC Evolutionary Biology | Year: 2012

Background: The major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations. Results: Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. Conclusions: The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian species. This result suggests that the Japanese black bears may also retain more potential resistance against pathogens than other endangered mammalian species. To prevent further decline of potential resistance against pathogens, a conservation policy for the Japanese black bear should be designed to maintain MHC rare variants in each local population. © 2012 Yasukochi et al.; licensee BioMed Central Ltd.


Kubota A.,Ehime University | Kubota A.,Woods Hole Oceanographic Institution | Watanabe M.X.,Ehime University | Kim E.-Y.,Kyung Hee University | And 3 more authors.
Environmental Pollution | Year: 2012

To validate the outcome of the national regulation on dioxins emission implemented in 1999, this study investigated temporal trends of chlorinated dioxins and related compounds (DRCs) in liver of common cormorants (Phalacrocorax carbo) collected from Lake Biwa, Japan between 2001 and 2008, as a part of the "Survey on the State of Dioxins Accumulation in Wildlife" conducted by the Ministry of the Environment, Japan. We also measured a biomarker of DRCs exposure, the cytochrome P450 1A (CYP1A)-dependent O-dealkylation activity of alkoxyresorufins (AROD), including methoxy-, ethoxy-, pentoxy- and benzyloxy-resorufins in the samples over 2001-2007. Neither TEQ nor AROD activity showed any clear declining trend over the time period, although the emission of DRCs during the corresponding period was estimated to be apparently decreasing. Our data indicate that the concentration of recalcitrant DRCs in the cormorant during 2001-2008 was scarcely affected by the national regulation on dioxins emission. © 2012 Elsevier Ltd. All rights reserved.


Dobata S.,University of Tokyo | Dobata S.,University of Ryukyus | Sasaki T.,University of Ryukyus | Sasaki T.,Fumakilla Ltd. | And 5 more authors.
Molecular Ecology | Year: 2011

How cooperation can arise and persist, given the threat of cheating phenotypes, is a central problem in evolutionary biology, but the actual significance of cheating in natural populations is still poorly understood. Theories of social evolution predict that cheater lineages are evolutionarily short-lived. However, an exception comes from obligate socially parasitic species, some of which thought to have arisen as cheaters within cooperator colonies and then diverged through sympatric speciation. This process requires the cheater lineage to persist by avoiding rapid extinction that would result from the fact that the cheaters inflict fitness cost on their host. We examined whether this prerequisite is fulfilled, by estimating the persistence time of cheaters in a field population of the parthenogenetic ant Pristomyrmex punctatus. Population genetic analysis found that the cheaters belong to one monophyletic lineage which we infer has persisted for 200-9200 generations. We show that the cheaters migrate and are thus horizontally transmitted between colonies, a trait allowing the lineage to avoid rapid extinction with its host colony. Although horizontal transmission of disruptive cheaters has the potential to induce extinction of the entire population, such collapse is likely averted when there is spatially restricted migration in a structured population, a scenario that matches the observed isolation by distance pattern that we found. We compare our result with other examples of disruptive and horizontally transmissible cheater lineages in nature. © 2010 Blackwell Publishing Ltd.


Furusawa T.,Kyoto University | Sirikolo M.Q.,National Herbarium and Botanical Gardens | Sasaoka M.,Hokkaido University | Ohtsuka R.,Japan Wildlife Research Center
Journal of Ethnobiology and Ethnomedicine | Year: 2014

Background: In Solomon Islands, forests have provided people with ecological services while being affected by human use and protection. This study used a quantitative ethnobotanical analysis to explore the society-forest interaction and its transformation in Roviana, Solomon Islands. We compared local plant and land uses between a rural village and urbanized village. Special attention was paid to how local people depend on biodiversity and how traditional human modifications of forest contribute to biodiversity conservation.Methods: After defining locally recognized land-use classes, vegetation surveys were conducted in seven forest classes. For detailed observations of daily plant uses, 15 and 17 households were randomly selected in the rural and urban villages, respectively. We quantitatively documented the plant species that were used as food, medicine, building materials, and tools.Results: The vegetation survey revealed that each local forest class represented a different vegetative community with relatively low similarity between communities. Although commercial logging operations and agriculture were both prohibited in the customary nature reserve, local people were allowed to cut down trees for their personal use and to take several types of non-timber forest products. Useful trees were found at high frequencies in the barrier island's primary forest (68.4%) and the main island's reserve (68.3%). Various useful tree species were found only in the reserve forest and seldom available in the urban village. In the rural village, customary governance and control over the use of forest resources by the local people still functioned.Conclusions: Human modifications of the forest created unique vegetation communities, thus increasing biodiversity overall. Each type of forest had different species that varied in their levels of importance to the local subsistence lifestyle, and the villagers' behaviors, such as respect for forest reserves and the semidomestication of some species, contributed to conserving diversity. Urbanization threatened this human-forest interaction. Although the status of biodiversity in human-modified landscapes is not fully understood, this study suggested that traditional human modifications can positively affect biodiversity and that conservation programs should incorporate traditional uses of landscapes to be successful. © 2014 Furusawa et al.; licensee BioMed Central Ltd.


Sueyoshi S.,Kibi International University | Ohtsuka R.,Japan Wildlife Research Center
Biodemography and Social Biology | Year: 2010

An interview survey of 450 Muslim women in a rural village of south Jordan under the early stage of fertility transition was conducted to explore major causes of contraceptive use, taking both their sociodemographic attributes and fatwa (Islamic jurisprudence)-based perception into account. Discriminant analysis, which was performed for the subject women divided into 15- to 29-, 30- to 39-, and 40- to 49-year age groups, revealed that "the number of living children" in the former and "to do contraception for good care of children" in the latter played significant roles in discrimination into contraceptive user and nonuser groups for any age groups. To cope with demographically and socioeconmically vulnerable situations, contraceptive prevalence rate should be increased by means of government-led family planning programs in cooperation with the imam (Muslim religious leaders and priests) through fatwa, in which special attention is paid to traditional norms, represented by good childcare. Copyright © Society for the Study of Social Biology.


Sekiyama M.,University of Tokyo | Roosita K.,Bogor Agricultural University | Ohtsuka R.,Japan Wildlife Research Center
Asia Pacific Journal of Clinical Nutrition | Year: 2012

Dietary habits of children, including snack foods consumption, in developing countries have seldom been investigated in relation to their nutrition and health. To assess the effects of snack foods consumption of 154 children aged 1-12 years in a rural village of West Java, Indonesia, a 3-hour-interval food recall survey for all meals and snack foods consumed in seven consecutive days for each subject, anthropometry, and interviews for sociodemographic indicators were conducted. Their overall prevalence of stunting and underweight was 69.5% and 35.7%. There were 221 foods consumed by the subjects, among which 68 foods were categorized as snack foods. Though the children of both <7 year and ≥7 year age groups consumed snack foods similarly throughout the day, the latter group only consumed larger amounts of energy from snack foods at school recess-times. The mean percent contribution of snack foods was 59.6% for fat, 40.0% for energy, 20.6% for calcium, and <10% for vitamins A and C. Half number of the subjects who snacked more than the median amount consumed less carbohydrate and vitamin C than the remaining half. Furthermore, the more snack-consuming group the lower z score for height-for-age (HAZ) among schoolchildren. To improve this nutritionally vulnerable situation, consumption of snack foods should be replaced by the non-snack foods which contain much higher nutrient density, i.e., 15 times for calcium and 32 times for vitamin A. Moreover, considering high snack foods consumption of ≥7 y age group at school, appropriate school nutrition programs should be promoted.


Sekiyama M.,University of Tokyo | Roosita K.,Bogor Agricultural University | Ohtsuka R.,Japan Wildlife Research Center
American Journal of Physical Anthropology | Year: 2015

This study investigated the growth trajectories and the relative relevance levels of nutrition, disease, and hormonal status at various developmental stages among children in adverse environments to provide population-based empirical evidence for the life history theory. Three years of longitudinal anthropometric data in 1-year intervals were obtained from 418 boys and girls aged 0 to 12 years at recruitment. Following the final measurement, the main survey, which included blood and feces sampling, 3-h interval food consumption recall surveys for energy and nutrient intakes and anthropometry, was performed. Blood and feces were used for detecting, respectively, anemia and hormonal (IGF-I and IGFBP-3) levels as well as intestinal helminthiasis (Ascaris, Trichuris, and hookworm). The major findings of this study are summarized as follows: 1) the growth velocity of the subject children lagged behind international standards during childhood and juvenility but caught up during early adolescence; 2) diseases, both intestinal helminths and anemia, had significant effects on growth in childhood but not at older ages; and 3) hormonal status significantly affected growth in the children, with its highest significance in early adolescence. A larger growth than international standards in early adolescence likely follows programmed hormonal mechanisms after the onset of puberty. The onset of puberty might be associated with adequate amounts of nutrient intake and be mediated by hormonal function, because the IGF-IZ score was significantly correlated with energy and protein intakes at the transitional period from juvenility to adolescence, when puberty occurs. Am J Phys Anthropol 157:94-106, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.


Numazawa M.,Frog House | Sengoku S.,Japan Wildlife Research Center
Current Herpetology | Year: 2011

Courtship and nesting behaviors and some reproductive parameters were reported for Eleutherodactylus monensis, a terrestrial leptdactylid frog endemic to Mona Island, Puerto Rico, for the first time on the basis of captive observations of two males and one female. The female, captured in the wild in April 1996, produced a total of 22 clutches, each consisting of 5-28 eggs (x̄±SD: 16.2±4.55), at intervals of 14-59 days (25±15.91) from December 1997 to May 2001. Approximately five days before each oviposition, the female started digging the ground with her hind-legs to make a nest concavity. Then, the female temporarily left the concavity, during which one of the males entered therein and started digging also with his hind-legs. The nest concavity eventually got to approximately 37-43 mm in diameter and 10-15 mm in depth. Then, the male moved out of it and started amplexus by mounting and holding the female. The amplectant pair moved to the concavity and the female resumed digging with her hind-legs. She, then, laid a clutch of eggs and buried it also with her hind-legs at a depth of approximately 5 to 40 mm and diameter of approximately 30 to 45 mm. The froglets, weighing 38-67 mg (57.9±6.12), hatched 15-23 days (18.8±2.86) after oviposition. © 2011 by The Herpetological Society of Japan.


Suguro T.,6 39 I Gontazaka | Nagano H.,Japan Wildlife Research Center
Acta Arachnologica | Year: 2015

A new salticid species of the genus Ictus is described as Icius rugosus, from Mukojima, Anijima and Hahajima Islands of the Ogasawara Islands, Japan. This species resembles the generic type I. hamatus (С. L. Koch 1846) but can be distinguished from the latter by genital morphologies in both sexes and male chelicera with ventral wrinkles. Additionally, I. daisetsuzartus Saito 1934 is newly synonymized with Sitticus ranieri (Peckham & Peckham 1909), as Matsuda (1997) pointed out first. As a result, Japanese species belonging to this genus is only the new species for the present. © 2015, Arachnological Society of Japan. All rights reserved.

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