Towards improved socio-economic assessments of ocean acidification’s impacts

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research.     

Herbivores and variation in the composition of specific phenolics of boreal coniferous trees: a search for patterns

Coniferous trees of different species, or of the same species growing at different locations, vary in the extent to which they are attacked by various herbivores and pathogens. Plant secondary metabolites might be a key to understanding some of this variation. At the site level, we investigated if there was an intra- or interspecies pattern for individual compounds (or for groups of compounds) and their relationship to indices of plant nitrogen and plant productivity. For example, do plants exhibit similar covariance in defence compounds when evaluated across a number of sites varying in productivity? Here, we concentrated on the phenolic profile of Pinus sylvestris, Picea abies, Juniperus communis and Pinus contorta. Our results indicate striking differences in secondary chemistry profiles of the twigs including needles of the trees and in the inter-relationships amongst individual compounds and groups of compounds. Flavonols occurred in high variety in P. sylvestris and were highly correlated with each other, differing from P. contorta. But the results of the factor analyses indicate an underlying pattern for flavonols of the coumaroyl type for P. contorta. In contrast, the compounds of the other tree species showed a low degree of inter-correlation. Co-occurring phenolics of different tree species were not correlated. Overall, our analysis of site indices indicated that plant productivity was not a useful predictor for the concentration of specific phenolics. The relationship amongst plant nitrogen and specific phenolics might be the result of two defence strategies (one related and the other not related to nitrogen content). This might enable the plant to shift its defences against attacks with a high degree of flexibility.     

Regeneration status of mangrove forests in Mida Creek,Kenya: a compromised or secured future?

The structure and regeneration patterns of Mida Creek mangrove vegetation were studied along belt transects at 2 forest sites of Mida Creek (3 degrees 20'S, 40 degrees 00'E): Uyombo and Kirepwe. Based on the species importance values, the dominant mangrove tree species in Mida were Ceriops tagal (Perr.) C. B. Robinson and Rhizophora mucronata Lamk. Tree density varied from 1197 trees ha(-1) at Kirepwe to 1585 trees ha(-1) at Uyombo and mean tree height was higher at the former site compared to the latter. The size-class structure at both localities of Mida showed the presence of more small trees than large ones. Spatial distribution pattern of adults and juveniles varied greatly between sites and they showed a close to uniform pattern (Morisita's Index I0 < 1) for trees, but a tendency to random distribution (I0 = 1) for juveniles. The present paper shows that unmanaged but exploited mangroves do not necessarily disappear, but change qualitatively from locally preferred R. mucronata to the less preferred C. tagal. Whereas the effects of this change on the ecological function of the mangrove cannot be estimated yet, the economical function of the mangrove has evidently weakened.     

Heavy metal accumulation by the halophyte species Mediterranean saltbush

To identify Cd- and Zn-accumulating plants exhibiting a high growth rate, seeds from the halophyte species Mediterranean saltbush (Atriplex halimus L.) were collected on a heavy-metal-contaminated site in southeastern Spain (Llano del Beal, Cartagena). Seedlings from this ecotype were exposed for 3 wk to 0.1 mM Cd or Zn in a nutrient solution in a fully controlled environment. All plants remained alive and no significant growth inhibition was recorded until the end of the experiment. Mean Cd and Zn accumulation in aerial parts was 830 and 440 mg kg(-1), respectively, and the rate of metal translocation even increased with the duration of stress exposure. Resistance to heavy metals in this species may be partly linked to precipitation of Cd in oxalate crystals in the stems. A Cd-induced decrease in glutathione concentration also suggests that phytochelatins overproduction may occur in these conditions. We conclude that Mediterranean saltbush, which is able to produce up to 5 Mg dry matter ha(-1) yr(-1), may be an effective species for phytoextraction and should be tested for this purpose in field conditions.     

Field-Based Evaluation Tool for Riparian Buffer Zones in Agricultural Catchments

Riparian buffer zones can improve water quality and enhance habitat, but a comprehensive yet rapid method that can assist the resource manager in assessing the effectiveness of buffers is not available. The aim of this paper is to describe and illustrate the use of a newly developed field-based evaluation tool for riparian buffer zones in agricultural catchments. The Buffer Zone Inventory and Evaluation Form (BZIEF) incorporates criteria-based scoring systems developed from literature review, subsequent peer-review, and then a pilot field study. Use of the BZIEF is demonstrated by comparing buffer zones in three catchments established for water quality and habitat improvement under the Water Fringe Option agrienvironment scheme in England in order to assess whether the buffers were likely to provide environmental enhancement. Results among the three catchments were generally similar; buffer zones scored highly for their abundant vegetation cover, lack of erosion, stream habitat quality, and sufficient width. Furthermore, previous grassland or arable land use did not substantially affect buffer zone ratings. However, the BZIEF indicated that inappropriate soil characteristics in one catchment were likely to constrain buffer zone effectiveness for improving water quality. In another catchment, poor riparian vegetation diversity and structure may yield ineffective habitat enhancement, according to the BZIEF. It was concluded that the BZIEF might be a useful tool for buffer zone comparison and monitoring, even though more work is needed to test and validate the method. For example, the BZIEF could be used to target appropriate locations for buffer zones and is flexible, so could be adapted for different policies, objectives and regions.     

Natural concentrations and reference values for trace elements in soils of a tropical volcanic archipelago

Fernando de Noronha is a small volcanic archipelago in the Southern Atlantic, some 350 km NE of the city of Natal in NE Brazil. These remote volcanic islands represent a largely pristine environment, distant from sources of anthropogenic contamination. This study was carried out to determine the natural concentrations of Ag, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, V and Zn in the A and B horizons of soils of Fernando de Noronha. The aims of the study were twofold: determine whether there is a relationship between the bedrock geology and soils and to establish quality reference values for soils from Fernando de Noronha. Soil samples were subjected to acid digestion by the USEPA method 3051A, and metals were determined by inductively coupled plasma emission spectrophotometry. The results showed that the trace element distribution largely reflects the geochemistry of the underlying volcanic rocks of the Remedios and Quixaba Formations. The results demonstrate that the concentrations of Ba, Cr, Zn, Ni and Cu from the soils of the volcanic Fernando de Noronha archipelago are higher than those found in soils from continental Brazil. However, concentrations of Ni, Cu and Co are lower in soils of the archipelago as compared to other volcanic islands throughout the world. The elevated trace element concentrations of the volcanic parent material of Fernando de Noronha soils seem to be the main factor governing the relatively high natural concentrations of trace elements.     

Retrospective assessment of a managed coastal realignment and lagoon restoration measure: the Geltinger Birk,Germany

We document and analyse the implementation process of a large combined coastal protection realignment and nature protection rewetting scheme, covering about 1000 ha at the German Baltic coast. The assessment reviews local planning documents, includes a media analysis, a tourist survey, stakeholder interviews and we provide criteria for measuring success, derived from the Systems Approach Framework (SAF) concept. The full process in the Geltinger Birk took over 25 years and was finished in 2013. The early years were characterised by strong local opposition, a polarization of the local society, misinformation and negative media coverage. Land purchase, the establishment of a local information centre with an environmental manager, improved public participation, a more pro-active media strategy and the readiness to accept compromises finally enabled a successful implementation. Today, a comprehensive tourism information and guidance system exists and the area became a popular tourist place. 80% of all visitors point out the outstanding nature experience and 87% are positive about the combined coastal protection and restoration measure. Parallel, major stakeholders changed their attitude and today are positive about the situation. However, the long timespan between initiation of the process and implementation of the measure, calls for a systematic, guided management approach, like the SAF. Especially, because climate change, sea level rise and increasing pressures on the coasts require a much faster implementation of adaptation measures in future.     

Atrazine toxicity to Handroanthus heptaphyllus,a nontarget species from a Brazilian biome threatened by agriculture

The economic basis of the Brazilian midwest is agriculture, concentrating most of the grain production in the country. With the purpose of increasing yield, farmers have intensified land use and the use of atrazine among other pesticides, which can supposedly compromise human health and photosynthetic metabolism of plant species from Cerrado, such as Handroanthus heptaphyllus. The aim of this study was to determine experimentally the sensitivity level of H. heptaphyllus to atrazine, by measuring gas exchange, chlorophyll a fluorescence, chloroplastidic pigments, and membrane permeability. The experiment was conducted in a factorial scheme. Nine‐month‐old H. heptaphyllus plants were treated with six realistic doses of atrazine: 0, 25, 50, 100, 200, and 400 g a.i. ha^–1 (corresponding to 10, 20, 40, 80, and 100% of the commercial dose recommended for corn crops, respectively), with five replications. Evaluations were performed at 12, 36, 84, 180, and 276 h after treatment application. Photosynthesis, the effective quantum yield of photosystem II, and electron transport rate were gradually reduced by the action of atrazine. On the other hand, the nonphotochemical quenching increased gradually, which indicates that this mechanism was not sufficient to avoid oxidative stress and cellular damage in H. heptaphyllus treated plants. Based on these results, we concluded that the action of the herbicide in the photosynthetic reduction occurs by the electron transport rate limitation. Therefore, H. heptaphyllus trees are at risk in Cerrado areas next to agricultural lands.     

Polymorphic ROS scavenging revealed by CCCP in a lizard

Ingestion of antioxidants has been argued to scavenge circulating reactive molecules (e.g., free radicals), play a part in mate choice (by mediating access to this important resource), and perhaps increase life span. However, recent work has come to question these relationships. We have shown elsewhere in the polychromatic lizard, Ctenophorus pictus, that diet supplementation of carotenoids as antioxidants does not depress circulating natural reactive oxygen species (ROS) levels and leads to no corresponding improvement of color traits. However, a much stronger test would be to experimentally manipulate the ROS levels themselves and assess carotenoid-induced ROS depression. Here, we achieve this by using carbonyl cyanide 3-chlorophenylhydrazone, which elevates superoxide (SO) formation approximately threefold at 10 μM in this model system. We then look for depressing effects on ROS of the carotenoids in order to assess whether ‘super-production’ of SO makes carotenoid effects on elevated ROS levels detectable. The rationale for this treatment was that if not even such elevated levels of SO are reduced by carotenoid supplementation, the putative link carotenoids, ROS depression, and mate quality (in terms of antioxidant capacity) is highly questionable. We conclude that there is no significant effect of carotenoids on mean SO levels even at the induced ROS levels. However, our results showed a significant interaction effect between carotenoid treatment and male color, with red males having higher ROS levels than yellow males. We suggest that this may be because different pigments are differently involved in the generation of the integumental colors in the two morphs with concomitant effects on ROS depletion depending on carotenoid uptake or allocation to coloration and antioxidation.