Temporal trends in abundance and phenology of migratory birds across the Italian Alps during a 20-year period

Introduction: Bird migration across mountainous regions has been studied usually at single sites due to the difficulty in employing and support a multi-site sampling effort. This may affect inference on migration whose scale is larger that a single site. The Progetto Alpi has been monitoring post-breeding bird migration through the Italian Alps with a network of several ringing stations since 1997. Until 2017, 666,471 ringing data of 191 different species were collected. Methods: Phenology of bird migration in terms of date of capture and the related elevational distribution during the sampling season (August-November) were analysed for 69 species. For a subset of 45 species the inter-annual variation in phenology along with trends in the number of ringed birds and in the ratio between the number of juveniles and adults ringed, were also analysed. Results: Migration through the Italian Alps occurred differently between species, with heterogeneity across species in the median date of capture and their elevational distribution. No linear trends in phenology were detected. For four species an annual linear increase of the ringed individuals was detected, while for other four species an annual linear decrease of the captures was detected. For two species, an increase of the ratio between the number of the juveniles and the number of adults ringed was detected. Conclusions: The long-term standardized monitoring of post-breeding migration allowed us to consolidate and increase knowledge of bird migration through Italian southern Alps. The information gathered allowed us to define the temporal and elevation distribution of passerine birds crossing the mountainous area, and to test interannual trends in the number of captures. The main purpose of this work was to report on the information collected in twenty years of field activity, providing a contribution to the understanding this complex phenomenon. Further investigations and more in-depth analyses are necessary to understand how environmental factors and species-specific eco-physiological traits interact and affect migratory strategies of passerine birds in the Italian Alpine region.

Landscape and Species Traits Co-Drive Roadkills of Bats in a Subtropical Island

The expansion of roads has threatened wildlife populations by driving casualties due to vehicle collisions. However, the ecological drivers of wildlife roadkills are not yet fully explored. We investigated the strength of landscape features and ecomorphological traits in determining spatial patterns of bat roadkills in Taiwan. In total, 661 roadkills that belonged to 20 bat species were acquired by citizen scientists between 2011 and 2019. The number and species richness of victim bats declined with increasing elevations with varying species compositions. Elevation and artificial light had significantly negative effects on the occurrence of roadkill, whereas protected area and its interaction with elevation had positive effects. Ordination analyses showed that roadkills were driven by different ecomorphological traits and landscape features. At low elevations, road casualties were associated with an aerial hawking hunting strategy. At higher elevations, roadkills were associated with higher elevational distribution. Roadkills of non-cave bats were associated with brighter environments, suggesting that bats might be exposed to higher risk when hunting insects near artificial light. Our findings suggest that management agencies shall consider both species traits and landscape features when planning impact assessments and mitigation practices of roadkills for bats and probably other wildlife, particularly when long environmental gradients are covered.

Elevational distribution ranges of vascular plant species in the Baekdudaegan mountain range, South Korea

The climate is changing rapidly, and this may pose a major threat to global biodiversity. One of the most distinctive consequences of climate change is the poleward and/or upward shift of species distribution ranges associated with increasing temperatures, resulting in a change of species composition and community structure in the forest ecosystems. The Baekdudaegan mountain range connects most forests from the lowland to the subalpine zone in South Korea and is therefore recognized as one of the most important biodiversity hotspots. This study was conducted to understand the distribution range of vascular plants along elevational gradients through field surveys in the six national parks of the Baekdudaegan mountain range. We identified the upper and lower distribution limits of a total of 873 taxa of vascular plants with 117 families, 418 genera, 793 species, 14 subspecies, 62 varieties, two forms, and two hybrids. A total of 12 conifers were recorded along the elevational gradient. The distribution ranges of Abies koreana, Picea jezoensis, Pinus pumila, and Thuja koraiensis were limited to over 1000 m above sea level. We also identified 21 broad-leaved trees in the subalpine zone. A total of 45 Korean endemic plant species were observed, and of these, 15 taxa (including Aconitum chiisanense and Hanabusaya asiatica) showed a narrow distribution range in the subalpine zone. Our study provides valuable information on the current elevational distribution ranges of vascular plants in the six national parks of South Korea, which could serve as a baseline for vertical shifts under future climate change.

Effects of habitat heterogeneity on the elevational distribution of bird diversity in a typical modern montane

The biodiversity in montane ecosystems is high but is threatened by rapid environmental change. Urbanization and other anthropogenic activities in the mountains surrounding cities can affect changes in land use and habitat heterogeneity. Moreover, patterns of habitat heterogeneity are closely related to elevation and have a major effect on montane biodiversity. The aim of this study was to analyze the effects of habitat heterogeneity on the vertical distribution pattern of bird diversity by characterizing the structure of the bird community, biodiversity, and landscape factors at different altitudes. Continuous monitoring of the breeding birds at Mount Tai from 2016 to 2019 revealed that forest reduced the diversity and abundance of birds and favored montane birds. Habitat composition varied at different altitudes. In the high-mountain belt and the middle-mountain belt, the habitat was primarily composed of forest. In contrast, artificial habitat was more common in the low-mountain belt. Bird abundance, species richness, and the Shannon-Wiener index decreased as the altitude increased, and the structure of the bird community significantly differed in the different belts. Some rare species tended to only occupy specific belts. Road density, number of habitat patches, patch density, and the percentage of forest significantly affected bird diversity. The effect of patch density was higher compared with other landscape factors. The “habitat amount hypothesis” was more suitable for explaining the elevational distribution pattern of bird diversity at Mount Tai. Sufficient habitat and more patches in the low-mountain belt supported higher bird diversity. The middle-mountain belt and high-mountain belt showed contrasting patterns. Our results highlight the effects of ongoing urbanization and human activities on montane biodiversity and emphasize the need for artificial habitats in the mountains surrounding cities to be managed.

Elevational Distribution of the Asian Tiger Mosquito, Aedes albopictus, in the Inland Mountain Area of Nagano and Yamanashi Prefectures, Japan

ABSTRACT Nagano and Yamanashi prefectures of Japan comprise an inland mountain area that extends widely north and south, with elevation varying greatly by location. Mosquitoes transmitting infectious disease have a diversity of habitats in Nagano and Yamanashi, and many species can be expected there. However, there have been few reports on mosquito fauna; in particular, little information is available on mosquitoes such as Aedes albopictus. The mosquito fauna was investigated to clarify their elevational distribution ranging from 317 to 1,534 m, focusing especially on Ae. albopictus, in 24 areas in Nagano and Yamanashi prefectures from July to September in 2012–16. Adult mosquitoes were collected using the Centers for Disease Control and Prevention traps in each area, in addition to larval mosquito collections at several temple and shrine precincts in each area. At sites where elevations were >800 m (14 sites), no adult Ae. albopictus were captured. In addition, larval Ae. albopictus were not collected at elevations >728 m (15 sites). Aedes albopictus was captured at 20 other sites (annual mean air temperature ranged from 9.4 to 15.2°C, July–September mean air temperature ranged from 19.9 to 25.0°C).