Ant community composition and functional traits in newly established grasslands within agricultural landscapes

1. Die fortschreitende Intensivierung und Fragmentierung der europäischen Agrarlandschaften führt zu einem dramatischen Rückgang der biologischen Vielfalt und der damit verbundenen Funktionen und bedroht wichtige Taxa wie Ameisen. Zur Aufrechterhaltung von Ökosystemdienstleistungen wie der durch Ameisen vermittelten Schädlingsbekämpfung birgt die gezielte Förderung von Graslandflächen ein großes Potenzial. 2. Diese Studie untersuchte Unterschiede in der Zusammensetzung von Ameisengemeinschaften (a) zwischen Getreidefeldern, altem Grasland und neu angelegten Graslandtransekten im Alter von drei Jahren; (b) in Abhängigkeit von funktionellen Eigenschaften wie Ernährung, Rekrutierungsverhalten und Koloniegröße; und in Verbindung mit (c) dem natürlichen Schädlingsbekämpfungspotenzial. 3. Der Ameisenartenreichtum unterschied sich nicht signifikant zwischen neuem und altem Grasland, war aber im Vergleich zu Getreidefeldern signifikant höher. Im Detail zeigte sich jedoch, dass die Artenzusammensetzung in den neu angelegten Graslandtransekten eher den Getreidefeldern ähnelte und eine verarmte Auswahl der Artengemeinschaft der alten Graslandflächen war. Der von den Ameisengemeinschaften bedeckte funktionelle Raum überlagerte sich zwischen alten und neuen Graslandflächen, war jedoch in den alten Graslandflächen erweitert. Die Schädlingsbekämpfung unterschied sich nicht signifikant zwischen den Habitattypen und konnte nicht mit der Prävalenz funktioneller Eigenschaften in Verbindung gebracht werden. 4. Synthese und Anwendungen Neue Grasländer können den Ameisenartenreichtum, deren Abundanz und die Schädlingsbekämpfung in Agrarökosystemen erhöhen. Drei Jahre nach ihrer Etablierung wurden neue Grasländer jedoch immer noch von gewöhnlichen Agrobiont-Ameisenarten dominiert und es fehlten Habitatspezialisten, die eine konstante Versorgung mit Nahrungsressourcen und lange zur Koloniegründung benötigen. Neue Grasländer stellen eine vielversprechende Massnahme zur Aufwertung von Agrarlandschaften dar, müssen aber längerfristig erhalten werden, um eine vergleichbare Biodiversität und Funktion zu gewährleisten.1. Ongoing intensification and fragmentation of European agricultural landscapes dramatically reduce biodiversity and associated functions, and threaten service providing key taxa such as ants. To sustain ecosystem services such as ant mediated pest control, the enhancement of perennial non-crop areas holds great potential. 2. This study investigated differences in ant community composition (a) between cereal fields, old grasslands, and newly established grassland transects of three years age; (b) depending on functional traits such as diet, recruitment behaviour and colony size; and linked to (c) natural pest control potential. 3. Ant species richness was not significantly different between new and old grasslands, but significantly higher compared to cereal fields. Contrary, ant community composition of new grasslands was more similar to cereal fields and distinct from the species-pool of old grasslands. The functional trait space covered by the ant communities overlapped between old and new grasslands, but was extended in the old grasslands. Pest control did not differ significantly between habitat types, and could not be linked to the prevalence of functional traits related to biocontrol services. 4. Synthesis and applications New grasslands can increase ant species richness, abundance and pest control in agroecosystems. However, three years after their establishment, new grasslands were still dominated by common agrobiont ant species and lacked habitat specialists, who require a constant supply of food resources and long colonization times. New grasslands hence represent a promising measure for enhancing agricultural landscapes, but must be preserved in the longer term to provide comparable biodiversity and functions

Ant community composition and functional traits in new grassland strips within agricultural landscapes

Abstract Ongoing intensification and fragmentation of European agricultural landscapes dramatically reduce biodiversity and associated functions. Enhancing perennial noncrop areas holds great potential to support ecosystem services such as ant‐mediated pest control. To study the potential of newly established grassland strips to enhance ant diversity and associated functions, we used hand collection data and predation experiments to investigate differences in (a) ant community composition and (b) biocontrol‐related functional traits, and (c) natural pest control across habitats in cereal fields, old grasslands, and new grassland transects of three years of age. Ant species diversity was similar between new and old grasslands, but significantly higher in new grasslands than in surrounding cereal fields. Contrary, ant community composition of new grasslands was more similar to cereal fields and distinct from the species pool of old grasslands. The functional trait space covered by the ant communities showed the same distribution between old and new grasslands. Pest control did not differ significantly between habitat types and therefore could not be linked to the prevalence of functional ant traits related to biocontrol services in new grasslands. Our findings not only show trends of convergence between old and new grasslands, but also indicate that enhancing ant diversity through new grasslands takes longer than three years to provide comparable biodiversity and functionality. Synthesis and applications: Newly established grasslands can increase ant species richness and abundance and provide a consistent amount of biocontrol services in agroecosystems. However, three years after their establishment, new grasslands were still dominated by common agrobiont ant species and lacked habitat specialists present in old grasslands, which require a constant supply of food resources and long colony establishment times. New grasslands represent a promising measure for enhancing agricultural landscapes but must be preserved in the longer term to promote biodiversity and resilience of associated ecosystem services

Changes in Community Composition and Functional Traits of Bumblebees in an Alpine Ecosystem Relate to Climate Warming

Climate warming has been observed as the main cause of changes in diversity, community composition, and spatial distribution of different plant and invertebrate species. Due to even stronger warming compared to the global mean, bumblebees in alpine ecosystems are particularly exposed to these changes. To investigate the effects of climate warming, we sampled bumblebees along an elevational gradient, compared the records with data from 1935 and 1936, and related our results to climate models. We found that bumblebee community composition differed significantly between sampling periods and that increasing temperatures in spring were the most plausible factor explaining these range shifts. In addition, species diversity estimates were significantly lower compared to historical records. The number of socio-parasitic species was significantly higher in the historical communities, while recent communities showed increases in climate generalists and forest species at lower elevations. Nevertheless, no significant changes in community-weighted means of a species temperature index (STI) or the number of cold-adapted species were detected, likely due to the historical data resolution. We conclude that the composition and functionality of bumblebee communities in the study area have been significantly affected by climate warming, with changes in land use and vegetation cover likely playing an additional important role

Home-and-away comparisons of life history traits indicate enemy release and founder effects of the solitary bee, Megachile sculpturalis

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