Population links between an insectivorous bird and moths disentangled through national-scale monitoring data.

Insects are key components of food chains, and monitoring data provides new opportunities to identify trophic relationships at broad spatial and temporal scales. Here, combining two monitoring datasets from Great Britain, we reveal how the population dynamics of the blue tit Cyanistes caeruleus are influenced by the abundance of moths - a core component of their breeding diet. We find that years with increased population growth for blue tits correlate strongly with high moth abundance, but population growth in moths and birds is less well correlated; suggesting moth abundance directly affects bird population change. Next, we identify moths that are important components of blue tit diet, recovering associations to species previously identified as key food sources such as the winter moth Operoptera brumata. Our work provides new evidence that insect abundance impacts bird population dynamics in natural communities and provides insight into spatial diet turnover at a national-scale.

Characterizing the trophy hunting debate on Twitter.

Social media is an arena of debate for contentious political and social topics. One conservation topic debated online is the acceptability of trophy hunting, a debate that has implications for national and international policy. We used a mixed-methods approach (grounded theory and quantitative clustering) to identify themes in the trophy hunting debate on Twitter. We examined commonly co-occurring categories that describe people's stances on trophy hunting. We identified 12 categories and 4 preliminary archetypes opposing trophy hunting-activism, scientific, condemning, and objecting-whose opposition derived from different moral reasoning. Few tweets (22) in our sample of 500 supported trophy hunting, whereas 350 opposed it. The debate was hostile; 7% of tweets in our sample were categorized as abusive. Online debates can be unproductive, and our findings may be important for stakeholders wishing to effectively engage in the trophy hunting debate on Twitter. More generally, we contend that because social media is increasingly influential, it is important to formally contextualize public responses to contentious conservation topics in order to aid communication of conservation evidence and to integrate diverse public perspectives in conservation practice.

Caracterización del debate sobre la cacería de trofeos en Twitter Resumen Las redes sociales son arenas de debate para temas políticos y sociales polémicos. Un tema de conservación que se debate en línea es la aceptación de la cacería de trofeos, cuya discusión tiene implicaciones políticas nacionales e internacionales. Usamos una estrategia de métodos mixtos (teoría fundamentada y datos cuantitativos agrupados) para identificar los temas en el debate sobre la cacería de trofeos en Twitter. Analizamos las categorías concurrentes más comunes que describían la postura de las personas con respecto al tema. Identificamos doce categorías y cuatro arquetipos preliminares en contra de la cacería de trofeos (activista, científico, condenatorio y opositor), cuya oposición derivó de diferentes razonamientos morales. Pocos tuits (22) en nuestra muestra de 500 apoyaban la cacería de trofeos, mientras que 350 se oponían a ella. El debate era hostil, pues 7% de los tuits en nuestra muestra estuvieron categorizados como abusivos. Los debates en línea pueden ser improductivos y nuestros descubrimientos pueden ser importantes para los actores que desean participar de forma efectiva en el debate sobre la cacería de trofeos en Twitter. De manera más generalizada, sostenemos que, debido a la creciente influencia de las redes sociales, es importante que las respuestas públicas a los temas polémicos de conservación estén contextualizadas de manera formal para así auxiliar a la comunicación de la evidencia de conservación y para integrar las diferentes perspectivas públicas en la práctica de la conservación.

Mechanisms underpinning community stability along a latitudinal gradient: Insights from a niche-based approach.

At large scales, the mechanisms underpinning stability in natural communities may vary in importance due to changes in species composition, mean abundance, and species richness. Here we link species characteristics (niche positions) and community characteristics (richness and abundance) to evaluate the importance of stability mechanisms in 156 butterfly communities monitored across three European countries and spanning five bioclimatic regions. We construct niche-based hierarchical structural Bayesian models to explain first differences in abundance, population stability, and species richness between the countries, and then explore how these factors impact community stability both directly and indirectly (via synchrony and population stability). Species richness was partially explained by the position of a site relative to the niches of the species pool, and species near the centre of their niche had higher average population stability. The differences in mean abundance, population stability, and species richness then influenced how much variation in community stability they explained across the countries. We found, using variance partitioning, that community stability in Finnish communities was most influenced by community abundance, whereas this aspect was unimportant in Spain with species synchrony explaining most variation; the UK was somewhat intermediate with both factors explaining variation. Across all countries, the diversity-stability relationship was indirect with species richness reducing synchrony which increased community stability, with no direct effects of species richness. Our results suggest that in natural communities, biogeographical variation observed in key drivers of stability, such as population abundance and species richness, leads to community stability being limited by different factors and that this can partially be explained due to the niche characteristics of the European butterfly assemblage.