Protecting an ecosystem service: approaches to understanding and mitigating threats to wild insect pollinators

Insect pollination constitutes an ecosystem service of global importance, providing significant economic and aesthetic benefits as well as cultural value to human society, alongside vital ecological processes in terrestrial ecosystems. It is therefore important to understand how insect pollinator populations and communities respond to rapidly changing environments if we are to maintain healthy and effective pollinator services. This paper considers the importance of conserving pollinator diversity to maintain a suite of functional traits to provide a diverse set of pollinator services. We explore how we can better understand and mitigate the factors that threaten insect pollinator richness, placing our discussion within the context of populations in predominantly agricultural landscapes in addition to urban environments. We highlight a selection of important evidence gaps, with a number of complementary research steps that can be taken to better understand: i) the stability of pollinator communities in different landscapes in order to provide diverse pollinator services; ii) how we can study the drivers of population change to mitigate the effects and support stable sources of pollinator services; and, iii) how we can manage habitats in complex landscapes to support insect pollinators and provide sustainable pollinator services for the future. We advocate a collaborative effort to gain higher quality abundance data to understand the stability of pollinator populations and predict future trends. In addition, for effective mitigation strategies to be adopted, researchers need to conduct rigorous field-testing of outcomes under different landscape settings, acknowledge the needs of end-users when developing research proposals and consider effective methods of knowledge transfer to ensure effective uptake of actions

Data from: Specialists in ancient trees are more affected by climate than generalists

Ancient trees are considered one of the most important habitats for biodiversity in Europe and North America. They support exceptional numbers of specialized species, including a range of rare and endangered wood-living insects. In this study, we use a dataset of 105 sites spanning a climatic gradient along the oak range of Norway and Sweden to investigate the importance of temperature and precipitation on beetle species richness in ancient, hollow oak trees. We expected that increased summer temperature would positively influence all wood-living beetle species whereas precipitation would be less important with a negligible or negative impact. Surprisingly, only oak-specialist beetles with a northern distribution increased in species richness with temperature. Few specialist beetles and no generalist beetles responded to the rise of 4°C in summer as covered by our climatic gradient. The negative effect of precipitation affected more specialist species than did temperature, whereas the generalists remained unaffected. In summary, we suggest that increased summer temperature is likely to benefit a few specialist beetles within this dead wood community, but a larger number of specialists are likely to decline due to increased precipitation. In addition, generalist species will remain unaffected. To minimize adverse impacts of climate change on this important community, long-term management plans for ancient trees are important

Reactive forest management can also be proactive for wood-living beetles in hollow oak trees

AbstractThe debate about whether proactive (focused on irreplaceable species) or reactive (focused on vulnerable species) conservation is more effective usually focuses on the global or multinational scale and knowledge of how these principles interact on-the-ground is lacking. Here we use the first long-term dataset on an entire oak-living beetle community in hollow oaks (Quercus spp.) to ask whether policy-driven conservation actions aimed at vulnerable species can also be proactive for unthreatened, but irreplaceable species. Hollow oaks are vital keystone structures that are rich in both vulnerable and irreplaceable wood-living beetles. We sampled in excess of 23,000 individuals from 307 species over four seasons, across the oak range in Norway. We assessed the importance of key environmental variables for vulnerable, irreplaceable and generalist species. We show that simple management actions taken to benefit vulnerable species in hollow trees could also contribute to preventing the decline of important, irreplaceable species. Clearing regrowth is predicted to increase vulnerable species richness by 75–100%, specialist richness by 65%, and to benefit two generalist species. Regrowth clearance is likely to be similarly beneficial in all oak-based habitats with hollow trees across Europe and North America. Increased oak circumference and local habitat quantity were also beneficial for species richness and influenced species composition. Based on this we provide advice for targeting conservation action. We suggest economic, carbon and recreational benefits of clearance that could increase the attractiveness of conservation for policy-makers. We show the importance of examining large-scale conservation planning principles at a local scale to elicit how they work on the ground where conservation actually happens

Protecting an ecosystem service: approaches to understanding and mitigating threats to wild insect pollinators

Insect pollination constitutes an ecosystem service of global importance, providing significant economic and aesthetic benefits as well as cultural value to human society, alongside vital ecological processes in terrestrial ecosystems. It is therefore important to understand how insect pollinator populations and communities respond to rapidly changing environments if we are to maintain healthy and effective pollinator services. This chapter considers the importance of conserving pollinator diversity to maintain a suite of functional traits and provide a diverse set of pollinator services. We explore how we can better understand and mitigate the factors that threaten insect pollinator richness, placing our discussion within the context of populations in predominantly agricultural landscapes in addition to urban environments. We highlight a selection of important evidence gaps, with a number of complementary research steps that can be taken to better understand: (i) the stability of pollinator communities in different landscapes in order to provide diverse pollinator services; (ii) how we can study the drivers of population change to mitigate the effects and support stable sources of pollinator services and (iii) how we can manage habitats in complex landscapes to support insect pollinators and provide sustainable pollinator services for the future. We advocate a collaborative effort to gain higher quality abundance data to understand the stability of pollinator populations and predict future trends. In addition, for effective mitigation strategies to be adopted, researchers need to conduct rigorous field testing of outcomes under different landscape settings, acknowledge the needs of end-users when developing research proposals and consider effective methods of knowledge transfer to ensure effective uptake of actions