Using population synchrony to target conservation action

Rapid declines in many widespread species are challenging traditional conservation approaches, and new strategies are urgently needed. Conventional approaches of identifying and reversing the effects of specific environmental drivers are rarely feasible for widespread species, because a broad range of environmental changes can be contributing to population declines across species' ranges. Instead we need to a) identify achievable routes to recovery by boosting productivity and/or survival and b) target funding and conservation actions to locations and/or time periods in which demographic rates are low and could be boosted. However, the effectiveness of such an approach will depend on the scale and consistency of variation in demographic rates across species' ranges. Consistent spatial variation in demography (eg productivity always high in some sites and low in others) would facilitate targeted long-term conservation action (eg through habitat management) to increase the frequency of sites with high productivity. However, annual variation in demographic rates could mean that targeted conservation actions are best delivered in specific years (eg by providing food or managing predators). This spatial and temporal variation is captured by measures of synchrony, a fundamental feature of population and community dynamics. In this study, we exploit synchrony in counts, demographic rates and associated environmental conditions for breeding birds across Europe, to deliver a step-change in understanding of how to address declines in widespread species.

Synchrony can be defined as the correlated fluctuation in, for example, the number of individuals present across sites. Synchrony can be relatively localised (often reflecting local habitat conditions and community interactions), or it can operate over hundreds of kilometres (often reflecting climatic conditions). Synchrony can also vary across species' ranges and through time. We will exploit this 'geography of synchrony' and any temporal changes in it to examine whether spatial and temporal patterns in synchrony reflect equivalent patterns in demographic rates (productivity and survival) and associated environmental conditions, and if they are consistent for species with similar characteristics. Strong links between synchrony in counts, rates and environmental conditions across communities would provide the platform for disrupting these patterns, enabling us to identify key sites for conservation actions and the temporal delivery of actions needed to reduce the frequency of conditions with low demographic rates and abundance.

Opportunities to quantify spatio-temporal variation in synchrony are rare because they require long-term data across broad spatial scales. Bird populations are excellent model systems because citizen science schemes exist that generate standardised measures of abundance and demography over requisite scales. Using European bird survey data to explore the demographic drivers of synchrony can also provide a current and critical conservation application of the ecological advances delivered. Across Europe, many widespread bird species have declined severely in recent decades, with declines most apparent amongst farmland birds, African-Eurasian migrants, and specialist species. Actions capable of addressing these declines are urgently needed but have remained elusive. We will use survey data from 80 species, collected from over 16500 sites across 18 countries to quantify whether the geographies of count and rate synchrony are 1) similar within species; 2) changing over time and 3) more similar for species sharing ecological traits. Linking these three key features of synchrony with equivalent patterns in environmental variables will allow identification of the environmental conditions influencing demographic rates, the scales at which they are operating, and thus the types and scales of conservation actions most likely to achieve population recovery.

The continued global declines of widespread species reported in the recent Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report demands a radical rethink of conservation action design and delivery. By defining and characterising the relationships between environmental synchrony, demographic rate synchrony and count synchrony, the proposed research exploits spatial and temporal variation in population structure and environmental conditions to establish a novel framework for designing and implementing conservation actions to mitigate or offset the impacts of environmental changes on widespread species. This research will be of direct relevance to conservationists and policy-makers involved with developing national and international conservation strategies, because it specifically addresses key questions about the type and scale of conservation action required to rescue declining populations, when the initial causes of the declines are unknown. We expect our findings to highlight a growing need for conservation actions to be targeted in time as well as space, for example, through concentrated predator management or resource supplementation in times and places when demographic rates are low. To date, conservation actions is primarily targeted spatially (e.g. protected area networks), but this novel dimension of targeting actions temporally (eg to offset the effects of years with harsh climatic conditions) is likely to be an increasingly important aspect of conservation strategy.

Across Europe, many common and widespread bird species have declined severely in recent decades, with declines most apparent amongst farmland birds, African-Eurasian migrants, and species with specialist habitat or diet requirements. This is a cause for great concern among policy-makers, conservationists and members of the public for whom these species hold great cultural value. Our findings of how best to boost demographic rates in migrants will be particularly beneficial to Parties to the Convention on Migratory Species (CMS) who are required to undertake actions to reduce effects of habitat degradation, but for whom it is not yet clear which actions are likely to be effective. Much effort is currently focused on identifying potential drivers of change in sub-Saharan Africa but improving, for example, breeding sites with low productivity, in order to increase the frequency of sites achieving high productivity, could provide an alternative route to addressing local declines across Europe. These findings will inform the design and delivery of conservation action through agri-environment schemes, forest management and protected area networks across Europe, with particular relevance to developments around the transition towards payment-by-results approaches and, in the UK, post-Brexit conservation strategies.

We will make use of our strong links to UK and European governments and NGOs, and the highly effective interface between researchers, policy-makers and amateur ornithologists provided by the BTO, to disseminate our findings through presentations to conservation bodies, government and volunteer groups, and through our involvement in international species management plans and conservation strategies. We will also report our findings and to the organisers of the PECBMS and Euro-CES citizen science surveys, and also make use of the full range of BTO publications to volunteers and interested members of the public to highlight our studies and their implications.