Abstract. Warming Arctic temperatures can drive changes in vegetation structure and function directly by stimulating plant growth or indirectly by stimulating microbial decomposition of organic matter and releasing more nutrients for plant uptake and growth. The arctic biome is currently increasing in deciduous shrub cover and this increase is expected to continue with climate warming. However, little is known how current deciduous shrub communities will respond to future climate induced warming and nutrient increase. We examined the plant and ecosystem response to a long-term (18 years) nutrient addition and warming experiment in an Alaskan arctic tall deciduous shrub tundra ecosystem to understand controls over plant productivity and carbon (C) and nitrogen (N) storage in shrub tundra ecosystems. In addition, we used a meta-analysis approach to compare the treatment effect size for aboveground biomass among seven long-term studies conducted across multiple plant community types within the Arctic. We found that biomass, productivity, and aboveground N pools increased with nutrient additions and warming, while species diversity decreased. Both nutrient additions and warming caused the dominant functional group, deciduous shrubs, to increase biomass and proportional C and N allocation to aboveground stems but decreased allocation to belowground stems. For all response variables except soil C and N pools, effects of nutrients plus warming were largest. Soil C and N pools were highly variable and we could not detect any response to the treatments. The biomass response to warming and fertilization in tall deciduous shrub tundra was greater than moist acidic and moist non-acidic tundra and more similar to the biomass response of wet sedge tundra. Our data suggest that in a warmer and more nutrient-rich Arctic, tall deciduous shrub tundra will have greater total deciduous shrub biomass and a higher proportion of woody tissue that has a longer residence time, with a lower proportion of C and N allocated to belowground stems.

The management of the marine environment requires effective temporal monitoring of communities and assemblages to detect any change above the level of natural variability. Even though sponges are usually abundant in subtidal hard substratum environments and have the ability to significantly influence other community members, they have often been excluded from monitoring programmes because they are taxonomically difficult and often hard to quantify compared to other marine groups. We consider the use of a morphological method to examine photoquadrat data collected at 3 hard substratum sites over a 10 yr period at Skomer Marine Nature Reserve, south-west Wales. Differences in the morphological assemblages and abundance were apparent between years, but the sponge assemblages showed rapid recovery (within 1 yr) to their original assemblage composition and abundance following declines. The changes were attributed to natural biological variation or a short-term impact, rather than any response to prolonged environmental change and there was no correlation between any of the changes in assemblages observed and the environmental variables measured. A comparison of morphological and species data enabled the same sponge assemblages to be identified at different sites, validating the method. This morphological approach to monitoring represents a cost-effective and realistic way of monitoring certain sponge assemblages.

Growing demand for palm oil is driving its expansion into the African tropics, potentially leading to significant carbon emissions if tropical forest is converted to palm monoculture. In this first study of a Central African oil palm concession (31,800 ha), we predict that the conversion of 11,500 ha of logged forest to a palm plantation in Gabon will release 1.50 Tg C (95% CI = [1.29, 1.76]). These emissions could be completely offset over 25 years through sequestration in planned forest set-asides given a 2.6:1 ratio of logged to converted forest. Using an agricultural suitability model, we find that careful national land-use planning could largely avoid high carbon emissions while meeting goals for palm oil production. We recommend that Gabon adopts a national carbon threshold for land conversion and requires concession-level set-aside ratios that meet no-net emissions criteria as mechanisms for steering plantations away from high carbon forests

3 Skomer Marine Nature Reserve, Countryside Council for Wales, Fishermans Cottage, Martins Haven, Haverfordwest, Pembrokeshire SA62 3BJ, UKSubmerged artificial surface imitates newly available habitat for settlement of marine fauna. It also enables study of the timing of benthic larval settlement. Such knowledge is important if the model of possible recovery after disturbance in protected areas is to be assessed. During this study recruitment of sessile benthic invertebrate fauna at spatial and temporal scales was investigated using artificial panels submerged in the Skomer Marine Nature Reserve (Wales, UK). Panels were exchanged monthly between May 2009 and September 2011 (with the exclusion of winter time). Recruitment was highly variable with regard to time and distribution; abundance and number of recruiting species varied significantly between sites (about 2 km apart from each other), depths (6 and 12 m), position on panels (top or underside) and years without any obvious trends. The highest number of individuals and highest values of species richness were at Bernies Rocks, at the greater depth and on the underside surface of panels. Bryozoans were the dominant taxon on panels in each studied year and month. Most macrofaunal species noted on panels exhibit a colonial life strategy with short-lived, non-feeding larval stage. Although many species settle all year round, levels of settlement usually peak in summer months, showing a seasonal recruitment pattern (Bugula fulva, Spirobranchus triqueter, Chorizopora brongniarti and Escharoides coccinea). Some species had a pronounced settlement peak in spring (e.g. Electra pilosa and Balanus crenatus).

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Sublittoral macrobenthic communities in the Skomer Marine Nature Reserve (SMNR), Pembrokeshire, Wales, were sampled at 10 stations in 1993, 1996, 1998, 2003, 2007 and 2009 using a Day grab and a 0.5 mm mesh. The time series is analysed using Similarities Profiles (SIMPROF) tests and associated methods. Q-mode analysis using clustering with Type 1 SIMPROF addresses multivariate structure among samples, showing that there is clear structure associated with differences among years. Inverse (r-mode) analysis using Type 2 SIMPROF decisively rejects a hypothesis that species are not associated with each other. Clustering of the variables (species) with Type 3 SIMPROF identifies groups of species which covary coherently through the time-series. The time-series is characterised by a dramatic decline in abundances and diversity between the 1993 and 1996 surveys. By 1998 there had been a shift in community composition from the 1993 situation, with different species dominating. Communities had recovered in terms of abundance and species richness, but different species dominated the community. No single factor could be identified which unequivocally explained the dramatic changes observed in the SMNR. Possible causes were the effects of dispersed oil and dispersants from the Sea Empress oil spill in February 1996 and the cessation of dredge-spoil disposal off St Annes Head in 1995, but the most likely cause was severe weather. With many species, and a demonstrable recovery from an impact, communities within the SMNR appear to be diverse and resilient. If attributable to natural storms, the changes observed here indicate that natural variability may be much more important than is generally taken into account in the design of monitoring programmes.

Sharp, J. H., Winson, M. K., Wade, S., Newman, P., Bullimore, B., Lock, K., Burton, M., Gibbs, R., Porter, J. S. (2008). Differential microbial fouling on the marine bryozoan Pentapora fascialis. ?Journal of the Marine Biological Association of the United Kingdom, 88, (4), 705-710. IMPF: 01.06 RONO: 00Marine fouling is a commercially important problem affecting abiotic and biotic surfaces. In this study we investigated the surface fouling on a colonial reef-building invertebrate, the bryozoan Pentapora fascialis, from the Welsh coast. We captured 300 scanning electron microscope (SEM) images of 5 colonies of the bryozoan P. fascialis in order to quantify the level of fouling on the exterior surfaces. Evidence for differential fouling was found to occur at several spatial scales, including between older and newer zooids, between proximal and distal regions of the same zooids and between colonies. The current year's growing zooids were found to have a higher level of fouling than older zooids. The difference in the mean level of fouling of proximal regions of zooids compared to distal regions was found to be significant in P. fascialis. In agreement with the differential fouling previously observed by other authors in the laminar bryozoan Flustra foliacea where the proximal region of a zooid was observed to have a higher level of fouling, the fouling coverage in P. fascialis was higher in the proximal region of zooids. A reduction of fouling on some bryozoan surfaces may be caused by production of antimicrobial compounds. Further studies of microbial fouling of a similar quantitative scale in other bryozoans could aid in the identification of novel antimicrobial agents useful for preventing microbial fouling on abiotic surfaces in the marine environment.Peer reviewe