Tadashi Miyashita

The University of Tokyo | Todai · Ecosystem studies

Mapping the expansion or reduction of rice fields is fundamental for food and water security, greenhouse gas emission accounting, and environmental management. The historical mapping of rice fields with satellite images is challenging because of the limited availability of remote sensing and training data from past decades. The use of phenology-bas...

Recent increases in wildlife cause negative impacts on humans through both economic and ecological damage, as well as the spread of pathogens. Understanding the population dynamics of wildlife is crucial to develop effective management strategies. However, it is difficult to estimate accurate and precise population size over large spatial and tempo...

Free-ranging cats are invasive species threatening biodiversity worldwide. They may also impose an environmental risk to humans and livestock through the transmission of zoonotic diseases. We investigated antibody levels against Toxoplasma gondii in free-ranging cats and black rats (definitive and representative intermediate hosts) by ELISA and det...

The Sado wrinkled frog (Glandirana susurra) is a recently described threatened amphibian species found only on Sado Island, a small island located off the north coast of Honshu, Japan. We conducted an extensive field survey and genetic analysis of G. susurra to identify its (1) large-scale distribution patterns, (2) remaining levels of genetic dive...

Land abandonment may decrease biodiversity but also provides an opportunity for rewilding. It is therefore necessary to identify areas that may benefit from traditional land management practices and those that may benefit from a lack of human intervention. In this study, we conducted comparative field surveys of butterfly occurrence in abandoned an...

Obtaining cooperation from the local people is a key factor in an efficient management of invasive species. However, conflicts between invasive species managers and local people occur, when the target species is strongly bonded with humans. To understand the attitudes and behaviors of local people toward the issues on free-roaming cats (Felis silve...

To determine large scales habitat suitability for focal species, habitat models derived from one region are often extrapolated to others. However, extrapolation can be inappropriate due to regional variation of habitat selection. Accounting for the ecological mechanisms causing such variation is necessary to resolve this problem. We focused on grey...

Urbanization is increasing globally with wide‐ranging consequences for biodiversity and the ecological processes it performs. Yet knowledge of the range of ecological processes supported by biodiversity in urban environments, and the different taxa that perform these processes is poorly understood. We used a text‐analysis approach to identify the r...

Land abandonment may decrease biodiversity but also provides an opportunity for rewilding. It is therefore necessary to identify areas that may benefit from traditional land management practices and those that may benefit from a lack of human intervention. In this study, we conducted comparative field surveys of butterfly occurrence in abandoned an...

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, which infects almost all mammals and birds. Felids are definitive hosts that shed oocysts of T. gondii with their feces, which is then transmitted by oral ingestion. The study analyzed the prevalence of T. gondii infection in free-ranging cats on Tokunoshima Island, Kagoshima Prefecture from...

The prevalence of Toxoplasma gondii infection in free-ranging cats on Tokunoshima Island was assessed by testing 125 serum samples using anti-T. gondii IgG Indirect Enzyme-Linked ImmunoSorbent Assay. The overall seropositivity rate was 47.2% (59/125). Seropositivity rates in cats with body weight >2.0 kg (57.4%) were significantly higher than in th...

Understanding how invasive predators impact native species is essential for the development of effective control strategies, especially in insular environments where alternative non-native prey species exist. We examined seasonal and spatial shifts in diet of feral cat Felis silvestris catus focusing on the predation on native streaked shearwaters,...

Optimization of spatial resource allocation is crucial for the successful control of invasive species under a limited budget but requires labor‐intensive surveys to estimate population parameters. In this study, we devised a novel framework for the spatially explicit optimization of capture effort allocation using state‐space population models from...

Free-ranging cats Felis silvestris catus are harmful to endemic species, especially on islands. Effective management practices require an understanding of their habitat use and population source at the landscape level. We aimed to identify the source of the free-ranging cat population on Tokunoshima Island, Japan, which harbors a variety of endemic...

Analyses of life history and population dynamics are essential for effective population control of wild mammals. We developed a model for the simultaneous estimation of seasonal changes in three parameters—population density, habitat preference and trap catchability of target animals—based on camera-trapping data and harvest records. The random enc...

Paddy fields play an important role as alternative habitats for various wetland-dependent species. Agricultural intensification in paddy fields, however, presents serious threats to these species. Here, we examined the environmental factors, including those related to modern farming practices, affecting the distribution of the Sado wrinkled frog (G...

Contaminants decrease adhesive strength by interfering with substrate contact. Spider webs adhering to moths present an ideal model to investigate how natural adhesives overcome contamination because moths' sacrificial layer of scales rubs off on sticky silk, facilitating escape. However, Cyrtarachninae spiders have evolved gluey capture threads th...

Dispersal as well as population growth is a key demographic process that determines population dynamics. However, determining the effects of environmental covariates on dispersal from spatial‐temporal abundance proxy data is challenging owing to the complexity of model specification for directional dispersal permeability and the extremely high comp...

Orb webs produced by araneoid spiders depend upon aggregate glue-coated capture threads to retain their prey. Moths are challenging prey for most spiders because their scales detach and contaminate the glue droplets, significantly decreasing adhesion. Cyrtarachne are moth-specialist orb-weaving spiders whose capture threads adhere well to moths. We...

Orb webs intercept and retain prey so spiders may subdue them. Orb webs are composed of sticky, compliant spirals of capture silk spun across strong, stiff major ampullate silk threads. Interplay between differences in the mechanical properties of these silks is crucial for prey capture. Most orb webs depend upon insects contacting several radial a...

Sandy beach ecosystems are decreasing worldwide and organisms living there are becoming threatened. The burrowing wolf spider Lycosa ishikariana is one such example. To establish effective conservation strategies under habitat fragmentation, we examined population genetic structure of L. ishikariana from mitochondrial cytochrome oxidase I gene and...

ON THE COVER: The cover image, by Candido Diaz et al., is based on the Research Article Silk structure rather than tensile mechanics explains web performance in the moth‐specialized spider, Cyrtarachne, DOI: 10.1002/jez.2212. Photo Credit: Sarah Han.

Organic farming aims to reduce the effect on the ecosystem and enhance biodiversity in agricultural areas, but the long-term effectiveness of its application is unclear. Assessments have rarely included various taxonomic groups with different ecological and economic roles. In paddy fields with different numbers of years elapsed since the transition...

Results of GLM showing the effects of farming type and season on the abundance of various arthropods. (PDF)

Types of fertilizer and pesticides that were applied to conventional paddy fields in our study area. (PDF)

Mean (±SE) abundance of various arthropods in different seasons. Left and right bars indicate organic and conventional farming, respectively. (PDF)

Arthropod abundance data used for the analyses. (XLSX)

Background: Invasive ecosystem engineers can facilitate their invasions by modifying the physical environment to improve their own performance, but this positive feedback process has rarely been tested empirically except in sessile organisms. The invasive crayfish Procambarus clarkii is an ecosystem engineer that destroys aquatic macrophytes, whic...

Spiders in the subfamily Cyrtarachninae, including bolas spiders, are moth specialists, and it has been suggested that these spiders initiate web-weaving under high humidity. Here we used Pasilobus hupingensis to experimentally test whether Cyrtarachninae spiders build webs exclusively under high humidity. The results showed that humidity, as well...

Creating a win-win relationship between biodiversity and human well-being is one of the major current challenges for environmental policy. One way to approach this challenge is to identify sites with both high biodiversity and high human interest in urban areas. Here, we propose a new systematic approach to identify such sites by using land prices...

Species distribution models. (DOCX)

Relationships between the search range and the number of the selected sites. (TIFF)

An aerial photograph of a typical urban area including large green spaces (Google map API). (TIFF)

An aerial photograph of typical small town area that is enclosed in a natural green space (Google map API). (TIFF)

An aerial photograph of a typical area located in local cities along a seaside or lakeside (Google map API). (TIFF)

An aerial photograph of a typical area with a complex mixture or edge of green spaces and residential sections (Google map API). (TIFF)

Earlier studies showed environmentally friendly farming (EFF) increased the populations of various organisms in agricultural landscapes, but the mechanisms of these increases were not well studied, due to a lack of knowledge on their temporal dynamics. Here, we examined spatio-temporal dynamics of Tetragnatha spiders, natural enemies of rice pests,...

In studies of habitat suitability at landscape scales, transferability of species-landscape associations among sites are likely to be critical because it is often impractical to collect datasets across various regions. However, limiting factors, such as prey availability, are not likely to be constant across scales because of the differences in spe...

Cumulative curves of cell numbers where breeding sites of buzzards were detected in five study sites for last three observation-years. (TIFF)

Proportions in areas of all types of forests and open-fields in five study sites. Proportions of deciduous and evergreen broad-leaved and planted coniferous forests within all types of forests, and those of paddy fields and grasslands within open-fields are also shown. (XLSX)

Maximum numbers of used-cells, numbers of breeding nests in a year when the used-cells were the maximum, number of studied cells, and year when the used-cells were maximum in each study sites. (XLSX)

Landscape compositions in five study sites for inferring habitat models of gray-faced buzzards in Japan. (TIFF)

Proportions of prey items fed on chicks of gray-faced buzzards in four studied regions in Japan. All those records were carried out using video cameras set close by the nests. Records by the cameras were conducted throughout the nestling periods. (TIFF)

Average nearest neighbor distances between gray-faced buzzard nests in five study-sites of Japan. Error bar shows standard error. (TIFF)

Ecosystem engineering, or the modification of physical environments by organisms, can influence trophic interactions and thus food web dynamics. Although existing theory exclusively considers engineers using autochthonous resources, many empirical studies show that they often depend on allochthonous resources. By developing a simple mathematical mo...

A long-standing interest in ecology and wildlife management is to find drivers of wildlife population dynamics because it is crucial for implementing the effective wildlife management. Recent studies have demonstrated the usefulness of state-space modeling for this purpose, but we often confront the lack of the necessary time-series data. This is p...

Despite recent attempts to quantify the relative strength of density- and trait-mediated indirect effects, rarely has the issue been properly addressed at the population level. Most research is based on short-term small-scale experiments in which behavioral and/or physiological responses prevail. Here we estimated the time-scales during which densi...

Marxan is reserve selection software that was developed to identify efficient, near-optimal spatial solutions to conservation planning. Here we describe its basic mechanisms and introduce previous studies to outline the program's use and potential applications. Marxan seeks sets of planning units to achieve a given conservation goal at minimum cost...

A consensus now holds that biodiversity conservation in agricultural landscapes is important in addition to the protection of pristine habitats, and the role of wildlife-friendly farming is increasing in this context. Paddy-dominated landscapes harbor a variety of organisms that primarily depend on wetlands, as opposed to those that inhabit dry ara...

In this book, the authors have addressed ecological, socioeconomic, political, and practical factors pertaining to social-ecological restoration of paddy-dominated landscapes. It is evident that both social and ecosystem dimensions of ecological restoration play fundamental roles in restoration success. In the concluding chapter, we synthesize key...

The evolutionary process of the unique web architectures of spiders of the sub-family Cyrtarachninae, which includes the triangular web weaver, bolas spider, and webless spider, is thought to be derived from reduction of orbicular 'spanning-thread webs' resembling ordinal orb webs. A molecular phylogenetic analysis was conducted to explore this hyp...

Target 11 of the Aichi Biodiversity Targets established in 2010 by the Convention on Biological Diversity aims to conserve at least 17% of terrestrial areas by 2020. Although global-scale conservation planning to achieve this target has already been attempted, conservation effectiveness strongly depends on region-specific natural and social factors...

A new species, Pardosa albomarginata, is described from Sadogashima Is., Niigata Prefecture, Japan.

Habitat connectivity is considered to have an important role on the persistence of populations in the face of habitat fragmentation, in particular, for species with conservation concern. However, it can also impose indirect negative effects on native species through the spread of invasive species. Here, we investigated direct and indirect effects o...

An increasing number of studies are being conducted to examine the density- or trait-mediated indirect effects of large herbivores on phytophagous insects. However, these effects are highly context dependent and no general trends have been made clear. We conducted a meta-analysis focusing on three factors capable of affecting detection of the indir...

Cyrtarachne is an orb-weaving spider belonging to the subfamily Cyrtarachninae (Araneidae) which includes triangular-web-building Pasilobus and bolas spiders. The Cyrtarachninae is a group of spiders specialized in catching moths, which is thought to have evolved from ordinary orb-weaving araneids. Although the web-building time of nocturnal spider...

Although the importance of landscape mosaicness for biodiversity has been repeatedly stressed in terrestrial ecosystems, the significance of its application in the ocean has rarely been addressed. This application appears to be particularly important in East and Southeast Asia because the coastal landscape is complicated by the presence of many isl...

Biodiversity has a hierarchical structure, consisting of genetic, species, and ecosystem levels. Although the importance of genetic and species diversities is well recognized from both basic and applied perspectives, there has been virtually no conceptualization of how and why ecosystem diversity matters from an ecological or socioecological perspe...

Abstract Declines of apex predators can cause dramatic increases of smaller predators and ensuing collapses of their prey. However, recent empirical evidence finds that the disappearance of apex predators does not reduce but can increase prey populations. This poses a great challenge in managing species interactions involving mesopredator release....

The importance of landscape heterogeneity to biodiversity may depend on the size of the geographic range of species, which in turn can reflect species traits (such as habitat generalization) and the effects of historical and contemporary land covers. We used nationwide bird survey data from Japan, where heterogeneous landscapes predominate, to test...

Landscapes in nature can be viewed as a continuum of small total habitable area with high fragmentation to widely spreading habitats. The dispersal‐mediated rescue effect predominates in the former landscapes, while classical density‐dependent processes generally prevail in widely spread habitats. A similar principle should be applied to population...

Although patch isolation and patch size have long been considered the two primary parameters affecting metapopulation processes, patch quality is now recognized as a third factor. The extent to which patch quality influences between-patch migration processes and local population sizes, however, is poorly understood. Using a mark-recapture survey fo...

The invasive crayfish Procambarus clarkii is an omnivore and an ecosystem engineer whose feeding mechanism has reduced the abundance of many native invertebrates and macrophytes. Since macrophytes provide refuges for aquatic insects, macrophyte depletion by crayfish might have indirect negative effects on animal prey in aquatic habitats. We postula...

Modernization of drainage systems is suspected of causing a deterioration in the biodiversity of paddy-dominated landscapes that are substitutes for natural wetlands. Here, we focused on the gray-faced buzzard (Butastur indicus), a top predator that inhabits agricultural landscapes in East Asia. We evaluated the impacts of drainage system moderniza...

Heptathela spiders of Okinawajima Is. were taxonomically revised using DNA sequence data. An analysis of mt-COI gene sequences revealed two clades (HY and HH), one of which (HY) was identified as Heptathela yanbaruensis because HY included specimens from Yona, the type locality of this species. To evaluate gene flow between HY and HH, the sequences...

With a focus on environmentally friendly rice farming, this unique book integrates both ecosystem and human dimensions of ecological restoration to provide strategies to promote sustainable agriculture and rural development. Paddy fields have multiple functions beyond their role of producing rice: They serve as refuge habitats for a range of wildli...

Invasive species and anthropogenic habitat alteration are major drivers of biodiversity loss. When multiple invasive species occupy different trophic levels, removing an invasive predator might cause unexpected outcomes owing to complex interactions among native and non-native prey. Moreover, external factors such as habitat alteration and resource...

For maintaining social and financial support for eradication programs of invasive species, quantitative assessment of recovery of native species or ecosystems is important because it provides a measurable parameter of success. However, setting a concrete goal for recovery is often difficult owing to lack of information prior to the introduction of...

In Japan, the density of Japanese tree frogs (Hyla japonica) may not be necessary high in traditional rice fields compared to modern fields because the modernization of drainage systems from shallow earthen ditches to deep concrete-line ones reduces the abundance of predators/competitors for tadpoles, such as dojo loach (Misgurnus anguillicaudatus)...

Male spider specimens collected in Thailand were identified as males of Anepsion japonicum Yaginuma 1962. There was no conclusive evidence that female specimens collected at the same time belong to the same species, because the female of the species has not been described. We compared morphological data and mt-COI sequencing data for these female s...

In this study, we aimed to investigate the habitat of grassland plants which flower in the spring, compared to the difference of the long-term mowing management of semi-natural grasslands in the Shimousa plateau in the Chiba Prefecture of Japan. In grassland plants which flower in the spring, Ranunculus japonicus and Lathyrus quinquenervius were fo...

Landscape supplementation, which enhances densities of organisms by combination of different landscape elements, is likely common in heterogeneous landscapes, but its prevalence and effects on species richness have been little explored. Using grassland-dwelling spiders in an agricultural landscape, we postulated that richness and abundances of majo...

We examined complex geographical patterns in the morphology of a kleptoparasitic spider, Argyrodes kumadai, across its distributional range in Japan. To disentangle biotic and abiotic factors underlying morphological variation, latitudinal trends were investigated in two traits, body size and relative leg length, across separate transition zones fo...

Ungulate herbivory can fundamentally aff ect terrestrial vegetation at the landscape and regional levels, but its impact has never been analyzed from meta-community perspectives. Here, we study a meta-community of forest ground-layer plants in a warm-temperate region along a clear gradient of deer density interplaying with gradients of other enviro...