Browsing by Subject "Bats"

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Animal-plant-interactions at different scales in changing tropical landscapes of southern Yunnan, China
(2012) Meng, Ling-Zeng; Martin, Konrad
Carabid beetles (Coleoptera: Carabidae) have widely been used to assess biodiversity values of different habitats in cultivated landscapes, but rarely in the humid tropics. This study aimed to investigate effects of land use change on the carabid assemblages in a tributary valley of the Mekong River in tropical southern Yunnan, China. The study area includes habitats of traditional land use systems (rice production and shifting cultivation successions) and was dominated by natural forests until about 30 years ago. Since then, large areas of forest have been, and still are, successively transformed into commercial rubber monoculture plantations. In total, 102 species of Carabidae (including Cicindelinae) were recorded from 13 sites over different seasons, using pitfall traps, Malaise traps and aerial collectors in trees. Cluster analysis and indicator species analysis showed that three types of habitat (rice field fallows, early natural successions and natural forest) possess a degree of uniqueness in species composition. Non-metric multidimensional scaling revealed that the environmental factors explaining 80% of the total variation in carabid assemblage composition are the degree of vegetational openness of a habitat and its plant species diversity. Rice field fallows had significantly higher numbers of species and individuals than any other type of habitat and are probably dominated by species originating from other regions. Carabid assemblages of young rubber plantations (5 and 8 years) were quantitatively similar to those of forests, but without species of significant indicator value. With increasing plantation age (20 and 40 years), the number of carabid species decreased. Increasing age and a further spatial expansion of rubber plantations at the expense of forest areas will have negative impacts on the native forest carabid assemblages with strongest effects on forest specialists and rare species.
Enhanced crop diversity but not smaller field size benefit bats in agricultural landscapes
(2025) Hiller, Thomas; Gall, Friederike; Grass, Ingo; Hiller, Thomas; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Gall, Friederike; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Grass, Ingo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
Context: Farmland biodiversity continues to decline due to the expansion and intensification of agriculture. Historically, efforts to conserve farmland biodiversity have focused on conserving habitats outside agricultural production areas. More recently, attention has turned to the conservation potential of the cropland matrix, where reducing field size and increasing crop diversity to promote crop heterogeneity can significantly benefit farmland biodiversity. Bats are one group of farmland species that have experienced dramatic declines over recent decades. Objectives: Here we investigated the effects of crop heterogeneity (crop diversity, field size) and landscape structural elements (e.g. length of linear structures, distance to forest, proportion of semi-natural habitat) on the activity of bat functional groups. Results: Increasing crop diversity led to greater bat activity, especially for open space foraging bats. However, contrary expectations, bat activity was not affected by heterogeneity in crop configuration, i.e. field edge density. Furthermore, structural landscape elements, including hedgerows and distance to forest, were important predictors of bat activity, especially for species that hunt in highly cluttered spaces. While crop diversity clearly benefited bat activity, the lack of effect of crop configurational heterogeneity on bat foraging activity may suggest heterogeneityarea trade-offs and intensive pesticide use in small-scale vegetable production. Conclusions: Therefore, in addition to maintaining high levels of crop diversity, promoting hedgerows and tree lines between farmland and woodland may facilitate bat activity across the agricultural landscape matrix. The combination of high crop heterogeneity and structural elements provides favorable hunting grounds for bats and may promote their conservation in agricultural landscapes.
Influence of ambient temperature on the phenology of the greater mouse‐eared bat (Myotis myotis)
(2023) Matthäus, Laura; Kugelschafter, Karl; Fietz, Joanna
In order to assess the consequences of climate change and evaluate its impacts on wildlife, it is essential to do so on a species-specific level. It is assumed that changes in the ambient temperature influence energy consumption as well as food availability and thus foraging behavior, reproduction, survival, and therefore population dynamics in bats. Based on this assumption, the present study aims to gain insights into the roosting and breeding behavior of the greater mouse-eared bat (Myotis myotis) in relation to changes of the ambient temperature. For this purpose, we investigated the effect of ambient temperature on the phenology of the greater mouse-eared bat by using activity data of the bats collected using light barriers at the maternity roosts. The light barrier used in this study is a system that detects the interruption of two light beams, for example, by a flying bat, and displays it as an electrical signal. The investigations have shown that 1. the higher the winter temperatures, the earlier the greater mouse-eared bats returned to the roosts to form the maternity colony; however, this was only true for ambient temperatures below 0.5°C, 2. birth season started earlier at higher spring temperatures, 3. the dissolution of maternity roosts occurred earlier with earlier birth season and at higher ambient temperatures during lactation. The results revealed that ambient temperature has an influence on the phenology of the greater mouse-eared bat. Depending on the respective life history stage, an increase in ambient temperature can have a positive or negative effect on the fitness of the animals. In recent years, mild winters have been recorded more frequently, which can have an influence on the behavior of bats. Warm winters within certain limits seem to lead to an earlier formation of the maternity colony, which can be positive or negative for the bats depending on persistent weather conditions and thus insect availability. In the course of climate change, we can also expect earlier spring events and an increase in spring temperature, as well as hot spells in summer. These warm springs and summers seem to lead to an earlier beginning of births, a faster development of the juveniles and an earlier dissolution of the maternity roost. An advance of reproductive activities can be assumed to increase the chance to survive the following winter in both mothers and their young, as they have more time to build up sufficient energy reserves for hibernation before winter starts. Due to the climatic changes, phenological changes of the bats be expected. This study highlights that in order to understand the impact of climate change on biodiversity, it is necessary to investigate in detail effects on a species-specific level and also to consider direct and indirect effects of ambient temperature on different life history stages.