Conservation practitioners, policy-makers and researchers work within shared spaces with many shared goals. Improving the flow of information between conservation researchers, practitioners and policy-makers could lead to dramatic gains in the effectiveness of conservation practice. However, several barriers can hinder this transfer including lack of time, inaccessibility of evidence, the real or perceived irrelevance of scientific research to practical questions, and the politically motivated spread of disinformation. Conservation Evidence works to overcome these barriers by providing a freely-available database of summarized scientific evidence for the effects of conservation interventions on biodiversity. The methods used to build this database -a combination of discipline-wide literature searching and subject-wide evidence synthesis -have been developed over the last 15 years to address the challenges of synthesizing large volumes of evidence of varying quality and measured outcome

Continued anthropogenic carbon dioxide emissions are acidifying our 16 oceans, and hydrogen ion concentrations in surface oceans are predicted to 17 increase 150% by 2100. Ocean acidification (OA) is changing ocean carbonate 18 chemistry, including causing rapid reductions in calcium carbonate availability 19 with implications for many marine organisms, including biogenic reefs formed by 20 oysters. The impacts of OA are marked. Adult oysters display both decreased 21 growth and calcification rates, while larval oysters show stunted growth, 22 developmental abnormalities, and increased mortality. These physiological 23 impacts are affecting ecosystem functioning and the provision of ecosystem 24 services by oyster reefs. Oysters are ecologically and economically important, 25 providing a wide range of ecosystem services, such as improved water quality, 26 coastlines protection, and food provision. OA has the potential to alter the 27 delivery and the quality of the ecosystem services associated with oyster reefs, 28 with significant ecological and economic losses. This review provides a 29 summary of current knowledge of OA on oyster biology, but then links these 30 impacts to potential changes to the provision of ecosystem services associated 31 with healthy oyster reefs.

Globally, non-native species (NNS) have been introduced and now often entirely replace native species in captive aquaculture; in part, a result of a perceived greater resilience of NSS to climate change and disease. Here, the effects of ocean acidification and warming on metabolic rate, feeding rate, and somatic growth was 2 assessed using two co-occurring species of oysters-the introduced Pacific oyster Magallana gigas (formerly Crassostrea gigas), and native flat oyster Ostrea edulis. Biological responses to increased temperature and pCO2 combinations were tested, the effects differing between species. Metabolic rates and energetic demands of both species were increased by warming but not by elevated pCO2. While acidification and warming did not affect the clearance rate of O. edulis, M. gigas displayed a 40% decrease at ~750 ppm pCO2. Similarly, the condition index of O. edulis was unaffected, but that of M. gigas was negatively impacted by warming, likely due to increased energetic demands that were not compensated for by increased feeding. These findings suggest differing stress from anthropogenic CO2 emissions between species and contrary to expectations, this was higher in introduced M. gigas than in the native O. edulis. If these laboratory findings hold true for populations in the wild, then continued CO2 emissions can be expected to adversely affect the functioning and structure of M. gigas populations with significant ecological and economic repercussions, especially for aquaculture. Our findings strengthen arguments in favour of investment in O. edulis restoration in UK waters.

Ocean acidification and warming may threaten future seafood production, safety and quality by negatively impacting the fitness of marine species. Identifying changes in nutritional quality, as well as species most at risk, is crucial if societies are to secure food production. Here, changes in the biochemical composition and nutritional properties of the commercially valuable oysters, Magallana gigas and Ostrea edulis, were evaluated following a 12-week exposure to six ocean acidification and warming scenarios that were designed to reflect the temperature (+3°C above ambient) and atmospheric pCO 2 conditions (increase of 350-600ppm) predicted for the mid-to end-of-century. Results suggest that O. edulis, and especially M. gigas, are likely to become less nutritious (i.e. containing lower levels of protein, lipid, and carbohydrate), and have reduced caloric content under ocean acidification and warming. Important changes to essential mineral composition under ocean acidification and warming were evident in both species; enhanced accumulation of copper in M. gigas may

For many species, ocean acidification (OA) is having negative physiological consequences on their fitness and resilience to environmental change, but less is known about the ecosystem effects of these changes. Here, we assess how OA conditions predicted for 2100 affects the biological functioning of an important habitat-forming species Mytilus edulis and its susceptibility to predation by a key predator, the gastropod Nucella lapillus. Change in three physiological parameters in Mytilus were assessed: (1) shell thickness and cross-sectional surface area, (2) body volume and (3) feeding rate, as well as susceptibility to predation by N. lapillus. Shell thickness and cross-section area, body volume and feeding rate of Mytilus all reduced under OA conditions indicating compromised fitness. Predation risk increased by ∼26% under OA, suggesting increased susceptibility of mussels to predation and/or altered predator foraging behaviour. Notably, predation of large Mytilus - that were largely free from predation under control conditions - increased by more than 8x under OA, suggesting that body size was no longer a refuge. Our results suggest OA will impact upon ecosystem structure and functioning and the continued provision of ecosystem services associated with Mytilus reefs and the communities associated with them.