Roost selection by Mauritian tomb bats (Taphozus mauritianus) in Lilongwe city, Malawi – importance of woodland for sustainable urban planning

Increasing urbanisation has led to a greater use of artificial structures by bats as alternative roost sites. Despite the widespread presence of bats, roost availability may restrict their distribution and abundance in urban environments. There is limited quantitative information on the drivers of bat roost selection and roosting preferences, particularly in African bats. We explore the factors influencing roost selection in the Mauritian tomb bat (Taphozous mauritianus), within an urban landscape in Lilongwe city, Malawi. Eight building and five landscape features of roosts were compared with both adjacent and random control buildings throughout the city. Bat occupied buildings were situated closer to woodland (mean 709m) compared to random buildings (mean 1847m) but did not differ in any other landscape features explored. Roosts were situated on buildings with larger areas and taller walls, suggesting bats select features for predator-avoidance and acoustic perception when leaving the roost. Bats preferred buildings with exposed roof beams which may provide refuge from disturbance. Whilst roosts are situated more often on brick walls, this feature was also associated with landscape features, therefore its importance in roost selection is less clear. These results are indicative that T. mauritianus selects roosts at both the building and landscape level. The selectivity of T. mauritianus in relation to its roost sites implies that preferred roosts are a limited resource, and as such, conservation actions should focus on protecting roost sites and the woodland bats rely on

Organic farming enhances parasitoid diversity at the local and landscape scales

1. The magnitude of the benefits derived from organic farming within contrasting managed landscapes remains unclear and, in particular, the potential scale-dependent response of insect parasitoids is relatively unexplored. Identifying the scale at which parasitoids are affected by organic farming will be an important step to enhance their conservation. 2. We sampled tachinid parasitoids at the centre and margin of arable and grassland fields on paired organic and conventional farms located in landscapes with different proportions of organic land. A total of 192 fields were sampled in two biogeographical regions of the UK. 3. We found that the positive effect of organic farming on tachinid parasitoid diversity can be observed at multiple spatial scales. At the local scale, we found higher abundance and species richness of tachinid parasitoids on organic than on conventional farms and on field margins than on field centres. At the landscape scale, the diversity of tachinids was higher in landscapes with higher proportions of organic land. At both scales, the positive effect of organic farming was clear for arable fields, while it was almost neutral for grasslands. 4. Synthesis and applications. Any attempt to enhance parasitoid diversity in agricultural landscapes needs to consider the local management in relation to the habitat type, location within the field and agricultural management in the surrounding landscape. To restore parasitoid diversity, the promotion of organic agriculture should aim to increase both the total extent of organic farming and the connectivity of individual farms. As the benefits of organic farming to biodiversity clearly spread beyond individual farm boundaries, any assessment of organic farming should consider these positive externalities

Landscape impacts on pollinator communities in temperate systems: evidence and knowledge gaps

Summary 1. This review assesses current knowledge about the interplay between landscape and pollinator communities. Our primary aim is to provide an evidence base, identify key gaps in knowledge and highlight initiatives that will help develop and improve strategies for pollinator conservation. 2. Human-dominated landscapes (such as arable land and urban environments) can have detrimental impacts on pollinator communities but these negative effects can be ameliorated by proximity to semi-natural habitat and habitat corridors. There is also evidence to suggest that increased landscape heterogeneity and landscape configuration can play an important role in the maintenance of diverse pollinator communities. 3. Landscape characteristics have direct impacts on pollinator communities but can also influence abundance and richness through interaction with other drivers such as changing climate or increased chemical inputs in land management. 4. The majority of existing literature focuses on specific hymenopteran groups but there is a lack of information on the impact of landscape changes on non-bee taxa. Research is also needed on the effectiveness of management interventions for pollinators and multiple year observations are required for both urban and rural initiatives. 5. Current policies and monitoring schemes could contribute data that will plug gaps in knowledge, thus enabling greater understanding of relationships between landscapes and pollinator populations. This would in turn help design mitigation and adaptation strategies for pollinator conservation

Species' movement influence responses to habitat fragmentation

•Aim: Human conversion of land leads to habitat loss and fragmentation. The effects of habitat loss are well-established, but the effects of fragmentation beyond those of habitat loss, “fragmentation per se” (FPS), are intensely debated. One area of debate is how different species might respond to FPS. We will answer whether FPS have more negative effects on species that spend more time in the matrix and less on species with higher potential patch encounter rates. •Location: Virtual landscapes. •Methods: We simulated the effects of FPS on multiple species with different movement characteristics. All species moved with a random walk (RW), a correlated RW (CRW), or a habitat-dependent walk (HDW). Species also had increasing habitat bias which caused individuals to have a higher probability of moving into a more suitable habitat. The walk type modified the rate at which species encountered habitat patches. Increased bias caused individuals to spend more time in suitable habitats and less time in the matrix between patches. All species experienced higher mortality in less suitable habitats. We analysed FPS effects on species for whom the fragmented focal habitat was the most suitable. •Results: With bias, the species diversity of RW species declined with FPS, while FPS had little effect on the species diversity of species moving by CRW. For HDW species, spending less time in the matrix (moderate movement bias) caused species diversity to increase with FPS, but to decline with high bias. •Main conclusions: These results suggest that even for species that are dependent on fragmented habitat, FPS does not have a unidirectional effect. FPS can have a positive effect on species with high patch encounter rates (HDW with moderate bias) as their functional connectivity increases. These results help to explain why different studies show contradictory effects of FPS on biodiversity

Developing European conservation and mitigation tools for pollination services: approaches of the STEP (Status and Trends of European Pollinators) project

Pollinating insects form a key component of European biodiversity, and provide a vital ecosystem service to crops and wild plants. There is growing evidence of declines in both wild and domesticated pollinators, and parallel declines in plants relying upon them. The STEP project (Status and Trends of European Pollinators, 2010-2015, www.step-project.net) is documenting critical elements in the nature and extent of these declines, examining key functional traits associated with pollination deficits, and developing a Red List for some European pollinator groups. Together these activities are laying the groundwork for future pollinator monitoring programmes. STEP is also assessing the relative importance of potential drivers of pollinator declines, including climate change, habitat loss and fragmentation, agrochemicals, pathogens, alien species, light pollution, and their interactions. We are measuring the ecological and economic impacts of declining pollinator services and floral resources, including effects on wild plant populations, crop production and human nutrition. STEP is reviewing existing and potential mitigation options, and providing novel tests of their effectiveness across Europe. Our work is building upon existing and newly developed datasets and models, complemented by spatially-replicated campaigns of field research to fill gaps in current knowledge. Findings are being integrated into a policy-relevant framework to create evidence-based decision support tools. STEP is establishing communication links to a wide range of stakeholders across Europe and beyond, including policy makers, beekeepers, farmers, academics and the general public. Taken together, the STEP research programme aims to improve our understanding of the nature, causes, consequences and potential mitigation of declines in pollination services at local, national, continental and global scales.[ES] Los insectos polinizadores forman un componente clave de la biodiversidad europea, y proporcionan servicios vitales a los ecosistemas de plantas cultivadas y silvestres. Existe una creciente evidencia del declive de polinizadores silvestres y domesticados, y del declive paralelo de las plantas que dependen de ellos. El proyecto STEP (Estado y tendencias de los polinizadores europeos, 2010-2015, www.step-project.net) está documentando elementos críticos en la naturaleza y la extensión de estos declives, examinando características funcionales claves asociadas con el déficit de polinización, y desarrollando una Lista Roja de grupos de polinizadores europeos. Todas estas actividades juntas suponen el trabajo preliminar base para futuros programas de monitorización de polinizadores. STEP también investiga la importancia relativa de factores potenciales del declive de polinizadores, incluido el cambio climático, pérdida de hábitats y fragmentación, agroquímicos, patógenos, especies invasoras, contaminación lumínica, y otras interacciones. Se están midiendo los impactos ecológicos y económicos del declive de los servicios de polinizadores y de sus fuentes florales, incluyendo los efectos en las poblaciones de plantas silvestres, producción de cultivos y la alimentación humana. STEP está revisando las opciones de mitigación potenciales y las existentes, y proporcionando nuevos tests para su eficacia a lo largo de Europa. El trabajo se basa en modelos y conjuntos de datos desarrollados de novo y en otros ya existentes, complementados con campañas de trabajo de campo con replicación espacial para crear herramientas de soporte de decisiones basadas en la evidencia. STEP está estableciendo nexos de comunicación con un rango amplio de participantes a lo largo de Europa y fuera de ella, incluyendo a políticos, apicultores, granjeros, académicos y el público general. En conjunto, el programa de investigación STEP quiere mejorar nuestra comprensión de la naturaleza, las causas, consecuencias y mitigación potencial del declive de servicios de polinización a escala global, continental, nacional y localPeer reviewe

Regulating services

No abstract available

A method for the objective selection of landscape-scale study regions and sites at the national level

1. Ecological processes operating on large spatio-temporal scales are difficult to disentangle with traditional empirical approaches. Alternatively, researchers can take advantage of ‘natural’ experiments, where experimental control is exercised by careful site selection. Recent advances in developing protocols for designing these ‘pseudo-experiments’ commonly do not consider the selection of the focal region and predictor variables are usually restricted to two. Here, we advance this type of site selection protocol to study the impact of multiple landscape scale factors on pollinator abundance and diversity across multiple regions. 2. Using datasets of geographic and ecological variables with national coverage, we applied a novel hierarchical computation approach to select study sites that contrast as much as possible in four key variables, while attempting to maintain regional comparability and national representativeness. There were three main steps to the protocol: (i) selection of six 100 9 100 km2 regions that collectively provided land cover representative of the national land average, (ii) mapping of potential sites into a multivariate space with axes representing four key factors potentially influencing insect pollinator abundance, and (iii) applying a selection algorithm which maximized differences between the four key variables, while controlling for a set of external constraints. 3. Validation data for the site selection metrics were recorded alongside the collection of data on pollinator populations during two field campaigns. While the accuracy of the metric estimates varied, the site selection succeeded in objectively identifying field sites that differed significantly in values for each of the four key variables. Between-variable correlations were also reduced or eliminated, thus facilitating analysis of their separate effects. 4. This study has shown that national datasets can be used to select randomized and replicated field sites objectively within multiple regions and along multiple interacting gradients. Similar protocols could be used for studying a range of alternative research questions related to land use or other spatially explicit environmental variables, and to identify networks of field sites for other countries, regions, drivers and response taxa in a wide range of scenarios

The impact of over 80 years of land cover changes on bee and wasp pollinator communities in England

Change in land cover is thought to be one of the key drivers of pollinator declines, and yet there is a dearth of studies exploring the relationships between historical changes in land cover and shifts in pollinator communities. Here, we explore, for the first time, land cover changes in England over more than 80 years, and relate them to concurrent shifts in bee and wasp species richness and community composition. Using historical data from 14 sites across four counties, we quantify the key land cover changes within and around these sites and estimate the changes in richness and composition of pollinators. Land cover changes within sites, as well as changes within a 1 km radius outside the sites, have significant effects on richness and composition of bee and wasp species, with changes in edge habitats between major land classes also having a key influence. Our results highlight not just the land cover changes that may be detrimental to pollinator communities, but also provide an insight into how increases in habitat diversity may benefit species diversity, and could thus help inform policy and practice for future land management

Where is the UK's pollinator biodiversity? The importance of urban areas for flower-visiting insects

Insect pollinators provide a crucial ecosystem service, but are under threat. Urban areas could be important for pollinators, though their value relative to other habitats is poorly known. We compared pollinator communities using quantified flower-visitation networks in 36 sites (each 1 km2) in three landscapes: urban, farmland and nature reserves. Overall, flower-visitor abundance and species richness did not differ significantly between the three landscape types. Bee abundance did not differ between landscapes, but bee species richness was higher in urban areas than farmland. Hoverfly abundance was higher in farmland and nature reserves than urban sites, but species richness did not differ significantly. While urban pollinator assemblages were more homogeneous across space than those in farmland or nature reserves, there was no significant difference in the numbers of rarer species between the three landscapes. Network-level specialization was higher in farmland than urban sites. Relative to other habitats, urban visitors foraged from a greater number of plant species (higher generality) but also visited a lower proportion of available plant species (higher specialization), both possibly driven by higher urban plant richness. Urban areas are growing, and improving their value for pollinators should be part of any national strategy to conserve and restore pollinators