Visions of Nature and Environmental Sustainability: Shellfish Harvesting in the Dutch Wadden Sea

The concept of sustainability has several, sometimes contrasting, meanings that may generate confusion, misunderstanding, and conflict concerning conservation and restoration practices. It is therefore desirable to clarify the concept of sustainability, thereby potentially contributing to mutual understanding, especially when social conflicts arise. This article discusses a recently published typology of three conceptions of sustainability that range from economic to ecocentric valuations of nature. We argue that the typology is incomplete because it does not include the arcadian approaches. For this reason, we introduce a “tripolar model” for conceptions of sustainability, applying it to the debate on shellfish harvesting in the Dutch Wadden Sea. We conclude that the particular visions or conceptions of sustainability held by relevant actors may have an impact on strategies for conservation.     

Cell population indexes of spermatogenic yield and testicular sperm reserves in adult jaguars (Panthera onca)

The intrinsic yield of spermatogenesis and supporting capacity of Sertoli cells are the desirable indicators of sperm production in a species. The objective of the present study was to quantify intrinsic yield and the Sertoli cell index in the spermatogenic process and estimate testicular sperm reserves by histological assessment of fragments obtained by testicular biopsy of five adult jaguars in captivity. The testicular fragments were fixed in 4% glutaric aldehyde, dehydrated at increasing alcohol concentrations, included into hydroxyethyl methacrylate, and were cut into 4 μm thickness. In the seminiferous epithelium of the jaguar, 9.2 primary spermatocytes in pre-leptotene were produced by “A” spermatogonia. During the meiotic divisions only 3.2 spermatids were produced by a primary spermatocyte. The general spermatogenic yield of the jaguar was about 23.4 cells and each Sertoli cell was able to maintain about 19.2 germ cells, 11 of them were round spermatids. In each seminiferous epithelium cycle about 166 million spermatozoa were produced by each gram of testicular tissue. In adult jaguars, the general spermatogenic yield was similar to the yield observed in pumas, greater than that observed for the domestic cat, but less compared to most domestic animals.     

Patterns of species richness for vascular plants in China's nature reserves

Explaining the heterogeneous distribution of biodiversity across the Earth has long been a challenge to ecologists and biogeographers. Here, we document the patterns of plant species richness for different taxonomic groups in China's nature reserves, and discuss their possible explanations at national and regional scales, using vascular plant richness data coupled with information on climate and topographical variables. We found that water deficit, energy and elevation range (a surrogate of habitat heterogeneity) represent the primary explanations for variation in plant species richness of the nature reserves across China. There are consistent relationships between species richness and climate and habitat heterogeneity for different taxonomic vascular plant groups at the national scale. Habitat heterogeneity is strongly associated with plant richness in all regions, whereas climatic constraints to plant diversity vary regionally. In the regions where energy is abundant or water is scarce, plant richness patterns were determined by water and habitat heterogeneity, whereas in the region with low energy inputs, water interacting with energy, and habitat heterogeneity determined its species richness pattern. Our results also suggest that energy variables alone do not represent the primary predictor of plant richness.     

Consequences of early chilling stress in two Triticum species: plastic responses and adaptive significance

Phenotypic plasticity of two primitive wheat species (Triticum monococcum L. and Triticum dicoccum S.) was studied in response to early chilling stress. Selection pressure differentials, gradients and plasticity costs on plant morphogenesis, growth and reserve carbohydrate consumption were estimated. Regression analysis was applied to investigate differential developmental changes and patterns between treatments. Four‐day‐old seedlings of T. monococcum and T. dicoccum, differing in plant stature and reserve carbohydrates, were given an early chilling temperature (4 °C for 42 day) and compared with control plants grown at 23 °C. Early chilling stress resulted in a significant increase in leaf mass ratio (LMR) and relative growth rate (RGR), a reduction in flag leaf size, total biomass, specific leaf area (SLA) and reserve carbohydrate storage at flowering, together with advanced onset of flowering. Selection pressure within the early chilling environment favoured early flowering, smaller SLA, higher LMR and lower reserve carbohydrates, suggesting the observed responses were adaptive. Furthermore, a regression of daily cumulative plant biomass derived from a crop growth simulation model (CERES‐Wheat) on crop vegetation period revealed a divergent developmental pattern in early‐chilled plants. Using selection pressure gradient analysis, we found similar responses among these traits, except for SLA and sucrose, indicating that these two traits have indirect effects on fitness. Thus, the total effects of SLA and reserve sucrose on relative fitness seem to be buffered via the rapid growth rate in chilled plants. While lower SLA may reduce early chilling stress effects at an individual leaf level, a higher LMR and use of reserve carbohydrates indicated that compensatory growth of chilled plants during the recovery period relied on the concerted action of altered resource allocation and reserve carbohydrate consumption. However, a significant cost of plasticity was evident only for flowering time, LMR and fructan levels in the early chilling environment. Our results demonstrate that morphological and intrinsic developmental (ontogenetic) patterns in two Triticum species respond to early chilling stress.     

Maximising return on conservation investment in the conterminous USA

Efficient conservation planning requires knowledge about conservation targets, threats to those targets, costs of conservation and the marginal return to additional conservation efforts. Systematic conservation planning typically only takes a small piece of this complex puzzle into account. Here, we use a return‐on‐investment (ROI) approach to prioritise lands for conservation at the county level in the conterminous USA. Our approach accounts for species richness, county area, the proportion of species' ranges already protected, the threat of land conversion and land costs. Areas selected by a complementarity‐based greedy heuristic using our full ROI approach provided greater averted species losses per dollar spent compared with areas selected by heuristics accounting for richness alone or richness and cost, and avoided acquiring lands not threatened with conversion. In contrast to traditional prioritisation approaches, our results highlight conservation bargains, opportunities to avert the threat of development and places where conservation efforts are currently lacking.     

广东莲花山白盆珠省级自然保护区鸟类资源调查

于2008年1月～2010年12月对广东莲花山白盆珠省级自然保护区鸟类进行了调查,共记录到鸟类151种,隶属于45科16目。其中非雀形目鸟类74种(占49.01%),雀形目77种(50.99%);94种属东洋界种类(62.25%),42种属古北界种类(27.81%),15种属广布种(9.93%);留鸟88种(58.28%)、冬候鸟44种(29.14%)、夏候鸟15种(9.93%)、旅鸟和迷鸟4种(2.65%);国家Ⅱ级重点保护鸟类22种(14.57%)。该保护区鸟类特色是中华秋沙鸭种群数量较大,猛禽资源和水鸟资源较丰富。     

Differences of ecological functions inside and outside the wetland nature reserves in Sanjiang Plain, China

Conservation effectiveness of wetland nature reserves is determined by both the management intensity inside the reserves and the hydrological status outside the reserves. Therefore, differences of ecological functions inside and outside the reserves are an integrated indictor for assessing conservation effectiveness. Based on the land use map created from Landsat-TM satellite image and 1:50000 Digital Elevation Model (DEM) data in the study area, the catchments that belong to the wetland reserves were determined as their hydrological sensitive zones by SWAT (Soil and Water Assessment Tool) hydrological model. The ecological function indices of wetland reserves and their corresponding hydrological sensitive zones were calculated through expert consultation and value assessment on wetland ecosystem service functions. The results showed that the ecological functions of national wetland reserves were better than those of local reserves in general. However, the wetland ecological functions of hydrological sensitive zones of the former were not always better than those of the latter. Meanwhile, clustering analysis showed that the wetland ecological functions of several adjacent reserves in Nongjiang-Bielahonghe watershed were similar. But correlation analysis found that there existed a remarkable positive correlation between the wetland ecological function indices of local reserves and their hydrological sensitive zones.     

陕西米仓山自然保护区夏秋季鸟类调查

2006年7~10月,对陕西米仓山自然保护区的鸟类资源进行了调查研究。结果显示,保护区鸟类13目37科81属125种(亚种),鸟类种数分别占秦岭鸟类总种数的36·98%及陕西省鸟类总种数的33·42%。其中国家Ⅰ级重点保护野生动物1种,国家Ⅱ级重点保护野生动物12种,陕西省省级重点保护野生动物4种;我国特有鸟类13种;CITES附录Ⅱ鸟类10种。按区系成分划分,东洋种57种,古北种37种,广布种27种。按居留型划分,留鸟89种,夏候鸟32种,冬候鸟2种,旅鸟2种。与陕西佛坪、重庆大巴山等周边保护区相比,米仓山保护区的鸟类多样性比较丰富,区系成分以东洋种为主,并具有东洋界和古北界过渡区的特征。     

Light-induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate

Light induces both the germination of turions of the duckweed Spirodela polyrhiza and the degradation of the reserve starch stored in the turions. The germination photoresponse requires nitrate, and we show here that nitrate is also needed for the light-induced degradation of the turion starch. Ammonium cannot substitute for nitrate in this regard, and nitrate thus acts specifically as signal to promote starch degradation in the turions. Irradiation with continuous red light leads to starch degradation via auto-phosphorylation of starch-associated glucan, water dikinase (GWD), phosphorylation of the turion starch and enhanced binding of alpha-amylase to starch granules. The present study shows that all of these processes require the presence of nitrate, and that nitrate exerts its effect on starch degradation at a point between the absorption of light by phytochrome and the auto-phosphorylation of the GWD. Nitrate acts to coordinate carbon and nitrogen metabolism in germinating turions: starch will only be broken down when sufficient nitrogen is present to ensure appropriate utilization of the released carbohydrate. These data constitute the first report of control over the initiation of reserve starch degradation by nitrate.