Quantitative methods for defining percentage area targets for habitat types in conservation planning

The Earth’s resources are finite, therefore planning for their use requires the definition of broad goals and the formulation of operational targets derived from goals, that enable decisions to be made and success measured. The objective of this study was to review methods for the formulation of percentage conservation targets for the coverage of habitat types within a network of conservation areas. We reviewed the scope and data requirements of these methods and discussed the strengths and limitations of their application. We identified five groups of methods applicable to habitat types that define: (1) fixed percentage targets across all habitats based on species-area relationship, or habitat-specific targets based on (2) species-area relationship, (3) heuristic principles, (4) trade-off of target size with reserved area, or (5) spatially-explicit Population Viability Analysis (PVA) for selected species. No ideal method exists and two factors should guide the choice of a method: the type of biodiversity goal and data availability. Given the lack of perfect biodiversity data, we suggest the use of a composite target based on a combination of methods.     

Effects of dietary soy isoflavones on estrogenic activity,cortisol level,health and growth in rainbow trout,Oncorhynchus mykiss

Soy isoflavones (the phytoestrogens genistein, daidzein and glycitein) may act as estrogen receptor agonists or antagonists. The aim of this study was to examine the effect of dietary isoflavones on growth, reproduction and health in rainbow trout (Oncorhynchus mykiss). Rainbow trout fed three experimental diets containing different concentrations of isoflavones (0, 500 and 1,500 ppm). Growth, estrogenic activity, plasma estradiol levels, gonadal development, state of stress and histological changes in selected tissues were evaluated at the end of 70 days. Neither growth performance nor the relative mRNA levels of Insulin Growth Factor I (igf‐I) in the liver were influenced by different levels of dietary isoflavones. Plasma and liver vitellogenin (VTG) protein levels and plasma 17‐β‐estradiol (E₂) were unaffected by treatments, although the correlation between plasma levels of E₂ and VTG densitometry values was significant (p < .05). The fish gonadosomatic index (GSI) did not significantly differ among the three experimental groups but correlated with plasma VTG densitometry values (p < .05). Plasma, muscle and fin cortisol concentrations fell within the normal welfare range and were not correlated with isoflavone levels. Histologically, the distal intestine showed a normal morphology with well‐differentiated enterocytes and in the liver hepatocytes were also normal. A supranuclear accumulation of lipid droplets in enterocytes and some lipid droplets in hepatocytes were observed in all tested groups, suggesting an impact of basal dietary lipid on transport/metabolism of fat in the fish. Overall, the present results suggest that the doses of isoflavones tested do not compromise rainbow trout reproduction, growth and health.