Alberto Barausse

Making Robust Policy Decisions Using Global Biodiversity Indicators

In order to influence global policy effectively, conservation scientists need to be able to provide robust predictions of the impact of alternative policies on biodiversity and measure progress towards goals using reliable indicators. We present a framework for using biodiversity indicators predictively to inform policy choices at a global level. The approach is illustrated with two case studies in which we project forwards the impacts of feasible policies on trends in biodiversity and in relevant indicators. The policies are based on targets agreed at the Convention on Biological Diversity (CBD) meeting in Nagoya in October 2010. The first case study compares protected area policies for African mammals, assessed using the Red List Index; the second example uses the Living Planet Index to assess the impact of a complete halt, versus a reduction, in bottom trawling. In the protected areas example, we find that the indicator can aid in decision-making because it is able to differentiate between the impacts of the different policies. In the bottom trawling example, the indicator exhibits some counter-intuitive behaviour, due to over-representation of some taxonomic and functional groups in the indicator, and contrasting impacts of the policies on different groups caused by trophic interactions. Our results support the need for further research on how to use predictive models and indicators to credibly track trends and inform policy. To be useful and relevant, scientists must make testable predictions about the impact of global policy on biodiversity to ensure that targets such as those set at Nagoya catalyse effective and measurable change.

Long-term changes in community composition and life-history traits in a highly exploited basin (northern Adriatic Sea): the role of environment and anthropogenic pressures

The changes in a marine community in the northern Adriatic Sea were explored over a period of 65 years using landings data from a commercial fishing fleet, and the role of fishing pressure and environmental variations in driving these changes was investigated. A total of 40 taxonomic categories, including one or several species, were analysed, representing 93·7% of the total landings. From 1945 to 2010 a significant decrease in the evenness index was observed, indicating a trend towards landings dominated by fewer taxa. The composition of the landings showed a temporal shift during the 1980s; from 1945 to the 1980s a continuous, clear change in composition took place, probably driven by an increase in fishing pressure as well as riverine nutrient inputs. Since the 1980s, a different trend of changing composition emerged. Among the analysed predictors, fishing capacity, summer seawater temperature, inflow from the Po River (the major river of the northern Adriatic Sea) and nutrients were related to the changes in landings. In relation to life-history traits of the landed species, the community shifted from large, late-maturing species to more fecund, smaller and earlier-maturing species. A high fishing pressure is probably the major cause of these changes, possibly acting synergistically with environmental variations.

Improved heat tolerance in air drives the recurrent evolution of air-breathing

The transition to air-breathing by formerly aquatic species has occurred repeatedly and independently in fish, crabs and other animal phyla, but the proximate drivers of this key innovation remain a long-standing puzzle in evolutionary biology. Most studies attribute the onset of air-breathing to the repeated occurrence of aquatic hypoxia; however, this hypothesis leaves the current geographical distribution of the 300 genera of air-breathing crabs unexplained. Here, we show that their occurrence is mainly related to high environmental temperatures in the tropics. We also demonstrate in an amphibious crab that the reduced cost of oxygen supply in air extends aerobic performance to higher temperatures and thus widens the animals thermal niche. These findings suggest that high water temperature as a driver consistently explains the numerous times air-breathing has evolved. The data also indicate a central role for oxygen- and capacity-limited thermal tolerance not only in shaping sensitivity to current climate change but also in underpinning the climate-dependent evolution of animals, in this case the evolution of air-breathing.

Steps toward a shared governance response for achieving Good Environmental Status in the Mediterranean Sea

The Mediterranean region is of fundamental importance to Europe given its strategic position. The responsibility for its overall ecosystem integrity is shared by European Union Member States (EU-MS) and other Mediterranean countries. A juxtaposition of overlapping governance instruments occurred recently in the region, with the implementation of both the Marine Strategy Framework Directive (MSFD) for EU-MS and the Ecosystem Approach Strategy (ECAP) for all Mediterranean countries, including EU-MS. Both MSFD and ECAP are structured around vision-driven processes to achieve Good Environmental Status and a Healthy Environment, respectively. These processes have clear ecosystem-based, integrated policy objectives to guarantee the preservation and integrity of Mediterranean marine ecosystem goods and services. However, adoption of these instruments, especially those related to the new EUMS directives on marine policy, could result in a governance gap in addition to the well-known economic gap between the EU and the non-EU political blocs. We identify two complementary requirements for effective implementation of both MSFD and ECAP that could work together to reduce this gap, to ensure a better alignment between MSFD and ECAP and better planning for stakeholder engagement. These are key issues for the future success of these instruments in a Mediterranean region where discrepancies between societal and ecological objectives may pose a challenge to these processes.

Food web modeling of a river ecosystem for risk assessment of down-the-drain chemicals: A case study with AQUATOX

Conventional approaches to estimating protective ecotoxicological thresholds of chemicals, i.e. predicted no-effect concentrations (PNEC), for an entire ecosystem are based on the use of assessment factors to extrapolate from single-species toxicity data derived in the laboratory to community-level effects on ecosystems. Aquatic food web models may be a useful tool to improve the ecological realism of chemical risk assessment because they enable a more insightful evaluation of the fate and effects of chemicals in dynamic trophic networks. A case study was developed in AQUATOX to simulate the effects of the anionic surfactant linear alkylbenzene sulfonate and the antimicrobial triclosan on a lowland riverine ecosystem. The model was built for a section of the River Thames (UK), for which detailed ecological surveys were available, allowing for a quantification of energy flows through the whole ecosystem. A control scenario was successfully calibrated for a simulation period of one year, and tested for stability over six years. Then, the model ecosystem was perturbed with varying inputs of the two chemicals. Simulations showed that both chemicals rapidly approach steady-state, with internal concentrations in line with the input bioconcentration factors throughout the year. At realistic environmental concentrations, both chemicals have insignificant effects on biomass trends. At hypothetical higher concentrations, direct and indirect effects of chemicals on the ecosystem dynamics emerged from the simulations. Indirect effects due to competition for food sources and predation can lead to responses in biomass density of the same magnitude as those caused by direct toxicity. Indirect effects can both exacerbate or compensate for direct toxicity. Uncertainties in key model assumptions are high as the validation of perturbed simulations remains extremely challenging. Nevertheless, the study is a step towards the development of realistic ecological scenarios and their potential use in prospective risk assessment of down-the-drain chemicals.

Past and future challenges in managing European seas

Marine environments have undergone large-scale changes in recent decades as a result of multiple anthropogenic pressures, such as overfishing, eutrophication, habitat fragmentation, etc., causing often nonlinear ecosystem responses. At the same time, management institutions lack the appropriate measures to address these abrupt transformations. We focus on existing examples from social-ecological systems of European seas that can be used to inform and advise future management. Examples from the Black Sea and the Baltic Sea on long-term ecosystem changes caused by eutrophication and fisheries, as well as changes in management institutions, illustrate nonlinear dynamics in social-ecological systems. Furthermore, we present two major future challenges, i.e., climate change and energy intensification, that could further increase the potential for nonlinear changes in the near future. Practical tools to address these challenges are presented, such as ensuring learning, flexibility, and networking in decision-making processes across sectors and scales. A combination of risk analysis with a scenario-planning approach might help to identify the risks of ecosystem changes early on and may frame societal changes to inform decision-making structures to proactively prevent drastic surprises in European seas.

A Comparative Analysis of Trophic Structure and Functioning in Large-Scale Mediterranean Marine Ecosystems

The Mediterranean is a sea rich with many kinds of diversity. It is a hotspot of marine biodiversity which covers many habitats and environmental conditions, and is surrounded by three continents characterized by different cultures and degrees of socio-economic development, whose coastal human activities exert multiple pressures on the marine environment. Yet, surprisingly, the diversity in the structure and functioning of Mediterranean marine ecosystems has not been analyzed rigorously, especially on large spatial scales. Such information are critical to implement an Ecosystem Approach to the management of the Mediterranean Sea. To fill this gap, a comparative analysis of the South Catalan, the Northern-Central Adriatic, the Northern Adriatic and the North Aegean Seas was performed. Trophic network models of the marine pelagic environment in each system were assembled with Ecopath software, based on published datasets. To facilitate the comparison, models were constructed with the same number and kind of trophic groups. Multiple indicators from ecological network analysis were calculated and consistently highlighted similarities and differences among Mediterranean pelagic food webs. Shared traits included the key role of intermediate-trophic level species, the low overall impact exerted by large predators, and inefficiencies in the exploitation of phytoplankton and detritus production giving rise to high export flows fuelling the benthic compartment. Primary productivity markedly influenced food web properties, but additional differences in the global structure of trophic flows emerged, highlighting a great ecosystem diversity. The systems could be ranked in a clear order of development and maturity (from high to low): South Catalan, Northern-Central Adriatic, North Aegean, Northern Adriatic Sea.

Phytoplankton dynamics in the Gulf of Aqaba (Eilat, Red Sea): a simulation study of mariculture effects.

The northern Gulf of Aqaba is an oligotrophic water body hosting valuable coral reefs. In the Gulf, phytoplankton dynamics are driven by an annual cycle of stratification and mixing. Superimposed on that fairly regular pattern was the establishment of a shallow-water fish-farm initiative that increased gradually until its activity was terminated in June 2008. Nutrient, water temperature, irradiation, phytoplankton data gathered in the area during the years 2007-2009, covering the peak of the fish-farm activity and its cessation, were analyzed by means of statistical analyses and ecological models of phytoplankton dynamics. Two datasets, one from an open water station and one next to the fish farms, were used. Results show that nutrient concentrations and, consequently, phytoplankton abundance and seasonal succession were radically altered by the pollution originating from the fish-farm in the sampling station closer to it, and also that the fish-farm might even have influenced the open water station.

Biopotentiality as an index of environmental compensation for composting plants

The Biopotentiality Index is a landscape ecology indicator, which can be used to estimate the latent energy of a given land and to assess the environmental impacts due to the loss of naturalness on a landscape scale. This indicator has been applied to estimate the effectiveness of the measures put in place to provide an environmental compensation for the revamping of a composting plant. These compensation measures are represented by a green belt with a minimum width of 25 m all around the plant, representing both a windbreak and a buffer zone, and by two wide wooded zones acting as core natural areas. This case-study shows that the compensation index could be used as a key tool in order to negotiate the acceptance of waste treatment plant with the population.

Jellyfish Blooms and Their Impacts on Welfare Benefits: Recreation in the UK and Fisheries in Italy

Over the last decades, extensive jellyfish blooms have been recorded in several regions worldwide raising concern about a possible “jellification” of global seas. Potential causes of jellyfish blooms include overfishing, global warming, eutrophication, chemical pollution, the increase of artificial hard substrates, and the transport of exotic species in ballast water or for trade. Jellyfish blooms have negative impacts in a number of ways. Impacts on fisheries are the most frequently reported but the evidence base also includes impacts on aquaculture, energy production, tourism, and human health. Very few estimates of the welfare losses due to jellyfish blooms are available. We provide estimates of the potential welfare losses stemming from impacts of blooms on recreation in the UK and fisheries in Italy. Our estimates show that losses can be considerable. The evidence collected here and elsewhere in the literature warrants a consideration of increased efforts towards the monitoring and control of jellyfish blooms.