Sensitivity mapping for seabirds and offshore wind power farms : A case study of Slaty-backed gulls in Hokkaido

洋上風力発電は陸上風力発電よりも極めて大きな発電量を持つことから、近年気候変動問題の緩和策として最も有力視されている再生可能エネルギーのひとつである。その一方で、風車への海鳥の衝突等、野生動物への影響も懸念されている。このため、海鳥の生息に配慮した風力発電事業計画のための実用的なセンシティビティマップが求められるが、多くの国で作成されていない。本研究は、海鳥類への影響を最小限にとどめることを目的に、オオセグロカモメ Larus schistisagusをケーススタディとし、本種の生息場選択に関わる要因を明らかにし、センシティビティマップを作成した。 2018年 6－8月に、北海道道東地方に生息するオオセグロカモメ 6個体に GPSロガーを装着し 5分間隔で利用場所を特定した。オオセグロカモメの利用頻度は海水面温度、クロロフィル a、および営巣地からの距離が関係しており、海水面温度やクロロフィル aの上昇に伴い増加し、営巣地からの距離に応じて減少した。しかし、営巣地からの距離が 25 kmを越えた辺りからは横ばいとなった。これらの結果を用いてセンシティビティマップを作成したところ、営巣地に近接した海域だけでなく、遠方であっても潜在的に餌資源量が多い海域であれば、本種が風車に衝突する可能性が高くなることが示唆された。国内での洋上風力発電事業が計画されつつある今日では、本研究で示された手順で緊急にセンシティビティマップを作成し、事前の開発地選択に活用する必要がある。Offshore wind energy is a renewable energy source that offers an opportunity to reduce greenhouse gas emissions while increasing energy security. However, many ecologists have suggested that offshore wind farms may have severe negative impacts on wildlife, especially seabirds. Thus, balancing seabird conservation with human energy demands is necessary when developing wind farms. Bird sensitivity mapping is a powerful and practical tool that can determine turbine collision risk within specific areas; however, sensitivity maps have seldom been generated for seabirds. Focusing on the Slaty-backed gull (Larus schistisagus), a red-listed species that often collides with wind turbines, we determined factors affecting habitat selection with the goal of reducing negative impacts of offshore wind farms. We then generated a sensitivity map using habitat modeling. GPS loggers set to record at 5-minute intervals between June and August 2018 were attached to six Slaty-backed gulls residing in Ochiishi Bay, Nemuro Prefecture, Japan. A Gaussian mixed model indicated that habitat selection was related to food availability (as determined by sea surface temperature and chlorophyll a content) and distance to the nest site. Sea surface temperature and chlorophyll a content were positively related area visitation frequency of Slaty-backed gulls, whereas distance to nest site was negatively correlated. Moreover, area visitation frequency was unchanged when the distance from the nest site was > 25 km. The sensitivity map indicated that areas both near and far from nest sites with potentially abundant food resources were high-risk areas with respect to turbine collisions for Slaty-backed gulls. Based on these results, we advocate the use of sensitivity mapping to reduce interactions between offshore wind farms and seabirds, especially for species that often forage far from their nest sites

Antigen-specific immune responses to influenza vaccine in utero

Initial immune responses to allergens may occur before birth, thereby modulating the subsequent development of atopy. This paradigm remains controversial, however, due to the inability to identify antigen-specific T cells in cord blood. The advent of MHC tetramers has revolutionized the detection of antigen-specific T cells. Tetramer staining of cord blood after CMV infection has demonstrated that effective CD8+ antigen-specific immune responses can follow intrauterine viral infections. We hypothesized that sensitization to antigens occurs in utero in humans. We studied cord blood B and T cell immune responses following vaccination against influenza during pregnancy. Anti-Fluzone and anti-matrix protein IgM antibodies were detected in 38.5% (27 of 70) and 40.0% (28 of 70), respectively, of cord blood specimens. Using MHC tetramers, HA-specific CD4+ T cells were detected among 25.0% (3 of 12) and 42.9% (6 of 14) of cord blood specimens possessing DRB1*0101 and DRB1*0401 HLA types, respectively, and were detected even when the DRB1 HLA type was inherited from the father. Matrix protein–specific CD8+ T cells were detected among 10.0% (2 of 20) of HLA-A*0201+ newborns. These results suggest that B and T cell immune responses occur in the fetus following vaccination against influenza and have important implications for determining when immune responses to environmental exposures begin

Influence of farmland abandonment on the species composition of wetland ground beetles in Kushiro, Japan

Depopulation trends in many developed regions are resulting in an increase in areas of abandoned farmland, which could provide an alternative habitat for species endangered by past conversion of wetlands for agriculture. Additionally, various spatial and temporal factors (landscape structure, local habitat quality, and abandonment age) could influence species composition in abandoned farmland. In this study, we explored the spatio-temporal effects of land abandonment on the species composition of wetland ground beetles (Coleoptera: Carabidae) to examine whether abandoned farmland can contribute to conserve wetland species' habitats. We first compared ground beetle assemblages among four land uses (grassland, wetland, and newly and previously abandoned farmland) in the Kushiro region, eastern Hokkaido, Japan. We then examined the factors influencing differences in wetland species composition between abandoned farmland and wetland. We found that the composition of wetland species in abandoned farmland was more similar to that of wetland than that of grassland. Our results also showed that soil moisture in abandoned farmland was positively related to the land abandonment age and that differences in wetland species composition between abandoned farmland and wetland were negatively related to both soil moisture and surrounding wetland area. Our findings suggest that abandoned farmland can serve as an alternative habitat for wetland ground beetles. Maintaining a high level of soil moisture in abandoned farmland and conserving the surrounding wetland could be an effective strategy for restoring natural habitats for these species

Mobbing call experiment suggests the enhancement of forest bird movement by tree cover in urban landscapes across seasons

Local scale movement behavior is an important basis to predict large-scale bird movements in heterogeneous landscapes. Here we conducted playback experiments using mobbing calls to estimate the probability that forest birds would cross a 50-m urban area during three seasons (breeding, dispersal, and wintering seasons) with varying amounts of tree cover, building area, and electric wire density. We examined the responses of four forest resident species: Marsh Tit (Poecile palustris), Varied Tit (Sittiparus varius), Japanese Tit (P. minor), and Eurasian Nuthatch (Sitta europaea) in central Hokkaido, northern Japan. We carried out and analyzed 250 playback experiments that attracted 618 individuals. Our results showed that tree cover increased the crossing probability of three species other than Varied Tit. Building area and electric wire density had no detectable effect on crossing probability for four species. Seasonal difference in the crossing probability was found only for Varied Tit, and the probability was the highest in the breeding season. These results suggest that the positive effect of tree cover on the crossing probability would be consistent across seasons. We therefore conclude that planting trees would be an effective way to promote forest bird movement within an urban landscape

Seasonal variation in patch and landscape effects on forest bird communities in a lowland fragmented landscape

In fragmented temperate landscapes, species responses to patch and landscape structures are likely to vary across seasons. However, few studies have examined the dynamic effects on biodiversity across seasons. We examined the effects of patch attributes and connectivity and seasonal variation in the effects of these environmental variables on forest bird communities at woodland fragments surrounded by agricultural land across three seasons (breeding, dispersal, and wintering seasons). We surveyed birds in woodland remnants and examined the effects of patch area, woodland connectivity, woodland type, and three interaction terms between these environmental variables and season (patch area x season, connectivity x season, and woodland type x season) on forest bird communities. In the results, species richness, abundance and composition of forest bird communities were associated with patch attributes and connectivity, and some of these associations varied depending on the season. Specifically, there were significantly higher abundances of specialist birds in riparian woodlands compared to conifer woodlands during the breeding season, whereas this pattern was reversed during the winter. In addition, we found the negative effects of patch area during the dispersal and wintering seasons and the positive effect of connectivity during the dispersal season on generalist bird abundances. These results suggest that woodland patches with high conservation values differ among three seasons. The conservation planning for a fragmented landscape therefore needs to consider the role of patch attributes and connectivity during multiple seasons rather than just the breeding season

Urban permeability for birds : An approach combining mobbing-call experiments and circuit theory

The urban matrix was recently shown to be a mosaic of heterogeneous dispersal habitats. We conducted a playback experiment of mobbing calls to examine the probabilities of forest birds to cross a distance of 50 m over urban matrix with different land-cover types in an urban area. We treated the reciprocal of the crossing probabilities as a movement resistance for forest birds. We drew resistance surfaces based on the land-cover maps of urban Sapporo. We applied a circuit theory to examine the relative role of a detour route consisting of a riparian corridor and urban matrix for dispersing forest bird individuals from continuous forest to an isolated green space in the midst of an urban area. Our results showed that wood cover had the highest crossing probability, while open land (grassland and pavement) had the lowest probabilities. Buildings and water surface displayed an intermediate probability. Resistance surfaces and flow maps at 25- and 50-m resolutions were very similar and suggested that dispersing individuals are likely to use the intervening building areas that dominate the urban matrix rather than detour through riparian corridors. Our results showed the useful combination of experimental approaches and circuit theory, and the importance of the spatial configuration of corridors, as well as the composition and management of dispersal habitats, to landscape connectivity

Effects of land use and climate on the distribution of the Jungle Nightjar Caprimulgus indicus in Hokkaido, northern Japan

Although the relative importance of land use and climate to large-scale bird distributions has received great attention, it is difficult to separate the effects of land use and climate, and there are few studies on bird abundance distributions on a large scale. Here, we examined the effects of land use and climate on the abundance of the nocturnal Jungle Nightjar Caprimulgus indicus in Hokkaido, northern Japan. We chose 125 sampling sites with low correlations (vertical bar r vertical bar<0.58) between land use and climate, and combined a playback method with a hierarchical model (N-mixture model). We thereby accounted for the possibility that we could not detect all individuals during the field survey. Results show that Jungle Nightjar abundance was greater at sites within a 4-km radius of moderate forest cover (similar to 75%) and with high average temperatures during the breeding season. Moreover, the effects of land-use were greater than those of climate. Mapping predictions of Jungle Nightjar abundance indicated that suitable areas are distributed in southern and central Hokkaido and around the margins of montane zones. Factoring in the covariation of land use and climate, land use may be the most important driver of the distribution of the Jungle Nightjar in Hokkaido