Dynamic meta-analysis: a method of using global evidence for local decision making.

BACKGROUND: Meta-analysis is often used to make generalisations across all available evidence at the global scale. But how can these global generalisations be used for evidence-based decision making at the local scale, if the global evidence is not perceived to be relevant to local decisions? We show how an interactive method of meta-analysis-dynamic meta-analysis-can be used to assess the local relevance of global evidence. RESULTS: We developed Metadataset ( www.metadataset.com ) as a proof-of-concept for dynamic meta-analysis. Using Metadataset, we show how evidence can be filtered and weighted, and results can be recalculated, using dynamic methods of subgroup analysis, meta-regression, and recalibration. With an example from agroecology, we show how dynamic meta-analysis could lead to different conclusions for different subsets of the global evidence. Dynamic meta-analysis could also lead to a rebalancing of power and responsibility in evidence synthesis, since evidence users would be able to make decisions that are typically made by systematic reviewers-decisions about which studies to include (e.g. critical appraisal) and how to handle missing or poorly reported data (e.g. sensitivity analysis). CONCLUSIONS: In this study, we show how dynamic meta-analysis can meet an important challenge in evidence-based decision making-the challenge of using global evidence for local decisions. We suggest that dynamic meta-analysis can be used for subject-wide evidence synthesis in several scientific disciplines, including agroecology and conservation biology. Future studies should develop standardised classification systems for the metadata that are used to filter and weight the evidence. Future studies should also develop standardised software packages, so that researchers can efficiently publish dynamic versions of their meta-analyses and keep them up-to-date as living systematic reviews. Metadataset is a proof-of-concept for this type of software, and it is open source. Future studies should improve the user experience, scale the software architecture, agree on standards for data and metadata storage and processing, and develop protocols for responsible evidence use.

The challenge of biased evidence in conservation.

Efforts to tackle the current biodiversity crisis need to be as efficient and effective as possible given chronic underfunding. To inform decision-makers of the most effective conservation actions, it is important to identify biases and gaps in the conservation literature to prioritize future evidence generation. We used the Conservation Evidence database to assess the state of the global literature that tests conservation actions for amphibians and birds. For the studies in the database, we investigated their spatial and taxonomic extent and distribution across biomes, effectiveness metrics, and study designs. Studies were heavily concentrated in Western Europe and North America for birds and particularly for amphibians, and temperate forest and grassland biomes were highly represented relative to their percentage of land coverage. Studies that used the most reliable study designs-before-after control-impact and randomized controlled trials-were the most geographically restricted and scarce in the evidence base. There were negative spatial relationships between the numbers of studies and the numbers of threatened and data-deficient species worldwide. Taxonomic biases and gaps were apparent for amphibians and birds-some entire orders were absent from the evidence base-whereas others were poorly represented relative to the proportion of threatened species they contained. Metrics used to evaluate effectiveness of conservation actions were often inconsistent between studies, potentially making them less directly comparable and evidence synthesis more difficult. Testing conservation actions on threatened species outside Western Europe, North America, and Australasia should be prioritized. Standardizing metrics and improving the rigor of study designs used to test conservation actions would also improve the quality of the evidence base for synthesis and decision-making.

El Desafío de la Evidencia Sesgada en la Conservación Resumen Los esfuerzos para lidiar con la actual crisis de la biodiversidad necesitan ser tan eficientes y efectivos como sea posible dado el crónico subfinanciamiento. Para informar a los órganos de decisión sobre las acciones de conservación más efectivas, es importante identificar los sesgos y las brechas en la literatura de la conservación para priorizar generación de evidencias en el futuro. Usamos la base de datos Conservation Evidence para evaluar el estado de la literatura mundial que analiza las acciones para la conservación de anfibios y aves. Para los estudios dentro de la base de datos, investigamos su extensión espacial y taxonómica y su distribución a lo largo de biomas, medidas de efectividad y diseños de estudio. Los estudios se concentraron principalmente en Europa Occidental y en América del Norte en el caso de las aves y particularmente para los anfibios. Los biomas con mayor representación en relación con su porcentaje de cobertura de suelo fueron el bosque templado y los pastizales. Los estudios que utilizaron el diseño más confiable - impacto del control antes- después y ensayos controlados al azar - fueron los que presentaron mayor restricción geográfica y menor presencia dentro de la base de evidencias. También encontramos relaciones espaciales negativas entre el número de estudios y el número de especies amenazadas o con pocos datos a nivel mundial. Los sesgos y las brechas taxonómicas fueron evidentes para los anfibios y las aves - hubo órdenes enteros ausentes en la base de evidencias - mientras que otros taxones estuvieron representados pobremente en relación con la proporción de especies amenazadas que albergan. Las medidas utilizadas para evaluar la efectividad de las acciones de conservación con frecuencia fueron incompatibles entre los estudios, lo que las hace potencialmente menos comparables directamente y también dificulta la síntesis de las evidencias. Se debe priorizar el análisis de las acciones para la conservación de las especies que se encuentran fuera de Europa Occidental, América del Norte y Australasia. La estandarización de las medidas y el mejoramiento del rigor de los diseños de estudio que se usan para evaluar las acciones de conservación también mejoraría la calidad de la base de evidencias para la síntesis y la toma de decisiones.

Conservation planning in agricultural landscapes: hotspots of conflict between agriculture and nature.

AIM: Conservation conflict takes place where food production imposes a cost on wildlife conservation and vice versa. Where does conservation impose the maximum cost on production, by opposing the intensification and expansion of farmland? Where does conservation confer the maximum benefit on wildlife, by buffering and connecting protected areas with a habitable and permeable matrix of crop and non-crop habitat? Our aim was to map the costs and benefits of conservation versus production and thus to propose a conceptual framework for systematic conservation planning in agricultural landscapes. LOCATION: World-wide. METHODS: To quantify these costs and benefits, we used a geographic information system to sample the cropland of the world and map the proportion of non-crop habitat surrounding the cropland, the number of threatened vertebrates with potential to live in or move through the matrix and the yield gap of the cropland. We defined the potential for different types of conservation conflict in terms of interactions between habitat and yield (potential for expansion, intensification, both or neither). We used spatial scan statistics to find 'hotspots' of conservation conflict. RESULTS: All of the 'hottest' hotspots of conservation conflict were in sub-Saharan Africa, which could have impacts on sustainable intensification in this region. MAIN CONCLUSIONS: Systematic conservation planning could and should be used to identify hotspots of conservation conflict in agricultural landscapes, at multiple scales. The debate between 'land sharing' (extensive agriculture that is wildlife friendly) and 'land sparing' (intensive agriculture that is less wildlife friendly but also less extensive) could be resolved if sharing and sparing were used as different types of tool for resolving different types of conservation conflict (buffering and connecting protected areas by maintaining matrix quality, in different types of matrix). Therefore, both sharing and sparing should be prioritized in hotspots of conflict, in the context of countryside biogeography.