Application of the Red List Index for conservation assessment of Spanish vascular plants

The International Union for Conservation of Nature (IUCN) Red List Index (RLI) is used to measure trends in extinction risk of species over time. The development of 2 red lists for Spanish vascular flora during the past decade allowed us to apply the IUCN RLI to vascular plants in an area belonging to a global biodiversity hotspot. We used the Spanish Red Lists from 2000 and 2010 to assess changes in level of threat at a national scale and at the subnational scales of Canary Islands, Balearic Islands, and peninsular Spain. We assigned retrospective IUCN categories of threat to 98 species included in the Spanish Red List of 2010 but absent in the Spanish Red List of 2000. In addition, we tested the effect of different random and taxonomic and spatial Spanish samples on the overall RLI value. From 2000 to 2010, the IUCN categories of 768 species changed (10% of Spanish flora), mainly due to improved knowledge (63%), modifications in IUCN criteria (14%), and changes in threat status (12%). All measured national and subnational RLI values decreased during this period, indicating a general decline in the conservation status of the Spanish vascular flora. The Canarian RLI value (0.84) was the lowest, although the fastest deterioration in conservation status occurred on peninsular Spain (from 0.93 in 2000 to 0.92 in 2010). The RLI values based on subsamples of the Spanish Red List were not representative of RLI values for the entire country, which would discourage the use of small areas or small taxonomic samples to assess general trends in the endangerment of national biotas. The role of the RLI in monitoring of changes in biodiversity at the global and regional scales needs further reassessment because additional areas and taxa are necessary to determine whether the index is sufficiently sensitive for use in assessing temporal changes in species’ risk of extinction.     

The role of agri‐environment schemes in conservation and environmental management

Over half of the European landscape is under agricultural management and has been for millennia. Many species and ecosystems of conservation concern in Europe depend on agricultural management and are showing ongoing declines. Agri‐environment schemes (AES) are designed partly to address this. They are a major source of nature conservation funding within the European Union (EU) and the highest conservation expenditure in Europe. We reviewed the structure of current AES across Europe. Since a 2003 review questioned the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta‐analyses examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in response to AES, with the size of the effect depending on the structure and management of the surrounding landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We examined the change in effect size over time by merging the data sets of 3 recent meta‐analyses and found that schemes implemented after revision of the EU's agri‐environmental programs in 2007 were not more effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production (such as field margins and hedgerows) are more effective at enhancing species richness than those aimed at productive areas (such as arable crops or grasslands). Outstanding research questions include whether AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in intensively farmed areas, whether they are more or less cost‐effective for farmland biodiversity than protected areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson from the European experience is that AES can be effective for conserving wildlife on farmland, but they are expensive and need to be carefully designed and targeted.     

Use of genetic,climatic, and microbiological data to inform reintroduction of a regionally extinct butterfly

Species reintroductions are increasingly used as means of mitigating biodiversity loss. Besides habitat quality at the site targeted for reintroduction, the choice of source population can be critical for success. The butterfly Melanargia russiae (Esper´s marbled white) was extirpated from Hungary over 100 years ago, and a reintroduction program has recently been approved. We used museum specimens of this butterfly, mitochondrial DNA data (mtDNA), endosymbiont screening, and climatic‐similarity analyses to determine which extant populations should be used for its reintroduction. The species displayed 2 main mtDNA lineages across its range: 1 restricted to Iberia and southern France (Iberian lineage) and another found throughout the rest of its range (Eurasian lineage). These 2 lineages possessed highly divergent wsp alleles of the bacterial endosymbiont Wolbachia. The century‐old Hungarian specimens represented an endemic haplotype belonging to the Eurasian lineage, differing by one mutation from the Balkan and eastern European populations. The Hungarian populations of M. russiae occurred in areas with a colder and drier climate relative to most sites with extant known populations. Our results suggest the populations used for reintroduction to Hungary should belong to the Eurasian lineage, preferably from eastern Ukraine (genetically close and living in areas with the highest climatic similarity). Materials stored in museum collections can provide unique opportunities to document historical genetic diversity and help direct conservation.     

Relation of RNA/DNA ratios to growth for the scallop Euvola (Pecten) ziczac in suspended culture

We examined the relation of RNA/DNA ratios to growth for three size groups of the tropical scallop Euvola ziczac maintained in suspended culture at 8, 21 and 34 m in depth in the Golfo de Cariaco, Venezuel. Various growth parameters indicated that production decreased with depth. This was more likely due to a decrease in seston quality with depth than to temperatures or seston abundance (which were similar at the various depths studied). The RNA/DNA ratio was correlated with the G-index of muscle growth for juveniles (r ²=0.55). A much weaker correlation was observed for the maturing scallops (r ²=0.18), probably because of the interaction between reproductive and somatic growth. In fully mature scallops, somatic growth was negligible and the RNA/DNA ratios appeared to be inversely related to the level of physiological stress of the scallops. Whereas RNA/DNA ratios are difficult to interpret for maturing E. ziczac, because an increased ratio can be due to either increased gonadal or somatic growth, they are useful in predicting growth in juveniles and physiological stress in fully mature scallops.     

Morphometric and genetic analysis as proof of the existence of two sturgeon species in the Guadalquivir river

Morphometric and genetic methods were used to identify two sturgeon species, Acipenser naccarii Bonaparte, 1836, and A. sturio Linnaeus, 1758, captured in some of the principal rivers of the Iberian Peninsula, including the Guadalquivir. After measuring 25 Iberian specimens from a fishery and several Spanish and Portuguese museums and applying stepwise discriminant analysis (SDA), four specimens preserved in different museums [two specimens from the Guadalquivir river (EBD-8173 and EBD-8174), one specimen from the Tagus river (MUC1) and one specimen from the Mondego river (MUC46B)], as well as five specimens captured in the Guadalquivir river in the 1940s but not preserved (CM1, CM2, CM3, CM4 and CM5), were identified as A. naccarii. After cloning and characterisation of a satellite-DNA family, HindIII, from A.␣naccarii genome, its absence from the genome of A.␣sturio was determined. Using this satellite-DNA as a genetic marker and by means of dot-blotting, we demonstrate that the DNA of the two specimens captured during the mid-1970s in the Guadalquivir river cross-hybridised with HindIII satellite-DNA sequences of A.␣naccarii. We conclude that A. naccarii is autochthonous to the Iberian Peninsula and is not, as was previously believed, endemic to the Adriatic Sea. Received: 28 November 1996 / Accepted: 10 March 1997     

Dynamics of a peculiar plant-herbivore relationship: the photosynthetic ascoglossan Elysia timida and the chlorophycean Acetabularia acetabulum

The ascoglossan mollusc Elysia timida Risso, 1818 retains functional chloroplasts from its algal food, the chlorophycean Acetabularia acetabulum (L.). Photosynthates from the plastids are an important source of organic nutrients for the mollusc. Chloroplast exploitation has an ecological function, allowing the ascoglossan to live entirely on an algal diet which is of limited, seasonal availability to other herbivores. Between October 1987 and July 1988, the annual evolution of the molluscan and algal populations was studied in a cove of Mazarrón Bay, southeast Spain. The population density of the mollusc is highly dependent on its food supply, being controlled by the seasonal life cycle of the algal population. During its life cycle, the degree of grazing by the mollusc decreases with increasing algal calcification, the cell walls of the alga progressively calcify, and the eventually highly calcificied stalks are completely resistant to ascoglossan grazing. In contrast, the exploitation of the algal chloroplasts retained by the molluscs increases during the seasonal cycle. The progressively increasing scarcity of food during the seasonal cycle may have led to the retention of symbiotic chloroplasts by E. timida. The developmental strategy of the ascoglossan also changes during the year: when food is abundant (in November, December, January, February and March) it is direct, with no planktonic larval phase, when food is scarce (in October, April, May and June) it is lecithotrophic, with a short planktonic larval phase. Chloroplast retention acts as a buffer, alleviating the effects of annual changes in density, structure and abundance of the alga on the nutritional state of the molluse.     

Actions of 17β-estradiol on carbohydrate metabolism in liver,gills, and brain of gilthead sea bream Sparus auratus during acclimation to different salinities

The influence of gonadal maturation on seawater adaptability at the metabolic level was assessed in the euryhaline teleost Sparus auratus by treatment of immature fish with 17ß-estradiol (E₂) followed by acclimation to different environmental salinities. Fish were injected with coconut oil alone (sham) or containing E₂ (10 µg g^–1 body weight) and maintained in seawater (40). After 5 days, fish from oil- and E₂-implanted groups were sampled. At the same time, fish of both groups were transferred to brackish water (5, hypoosmotic test), seawater (40, transfer test), and hypersaline water (55, hyperosmotic test); 4 days after transfer (9 days post-implant) all groups were sampled. Data obtained from liver suggest that E₂ treatment produced effects comparable to those already reported in literature, including decreased glycogen levels, increased glycolytic potential, and decreased gluconeogenic potential. This, together with the fact that many changes displayed in shams among salinities disappeared in E₂-treated fish allow us to suggest that the response of liver carbohydrate metabolism to osmotic acclimation is exceeded by the response elicited by E₂ treatment. In gills, E₂ treatment produced increased lactate levels, decreased capacity for use of exogenous glucose, and decreased the potential of the pentose phosphate pathway. These findings suggest that the energy demand occurring in gills during osmotic acclimation should be increasingly fuelled by substrates other than exogenous glucose. Finally, data obtained in brain of E₂-treated fish suggest a lower necessity of exogenous glucose, increased lactate levels, and decreased glycolytic potential.Communicated by S.A. Poulet, Roscoff     

Effects of salinity and dietary DHA (22:6n - 3) content on lipid composition and performance of Penaeus kerathurus postlarvae

A two-way ANOVA experiment was designed to study the effects of salinity and dietary docosahexaenoic acid (DHA; 22:6n-3) on lipid composition and performance of postlarvae from the marine shrimp Penaeus kerathurus (Forskål, 1775). Shrimp were reared from 1- to 8-d-old postlarvae at 35 and 25‰S with Kelko-enriched Artemia sp. [20.0 μg (n-3)?HUFA mg^?1 dry weight; 9.1 μg DHA mg^?1 dry weight] and nonenriched Artemia sp. [14.2 μg (n-3)?HUFA mg^?1 dry weight; 0.3 μg DHA mg^?1 dry weight]. Dietary DHA content did not affect either total length or survival but influenced the nutritional status represented by condition indices (triacylglycerol/total polar lipid and triacylglycerol/free cholesterol) of 8-d-old postlarvae at the end of the experiment. Culture salinity affected final total length and condition indices but did not show any effect on survival in the different experimental treatments. The interaction of dietary DHA and culture salinity was not significant for total length and survival but was significant for both condition indices used. P. kerathurus 8-d-old postlarvae showed better growth, survival and nutritional condition when reared at 35‰S and when fed on Kelko-enriched Artemia sp., but the differences with postlarvae from other treatments were very poorly marked. The results demonstrate that 8-d-old postlarvae may have sufficiently developed osmoregulatory capabilities to resist 25‰S under good conditions, although (n-3) HUFA-enriched diets may also enhance osmotic stress resistance, general performance and disease resistance.