Genotypic variation in foliar nutrient concentrations, δ13C,and chlorophyll fluorescence in relation to tree growth of radiata pine clones in a serpentine soil

This study investigated the genotypic variation in foliar nutrient concentrations, isotopic signature (δ¹³C), and chlorophyll fluorescence (F_v/F_m) and tree growth of 40 radiata pine clones grown on a New Zealand serpentine soil, and the relationships between growth and physiological traits of these clones from improved and unimproved groups. Genotypic variation in growth and physiological traits existed within (i.e., clonal) and between groups, with larger variation among clones. The clonal repeatabilities were greater for foliar nitrogen (N), calcium (Ca), magnesium (Mg), boron (B) concentrations, δ¹³C, and Ca : Mg ratio (0.35–0.64) than for growth traits (0.14–0.27) and other physiological traits (0.08–0.24). Significant phenotypic correlations were found between growth traits and foliar phosphorus (P), potassium (K), sulfur (S), iron (Fe), and K : Mg and Ca : Mg ratios and F_v/F_m (positive), and foliar Mg (negative). This study indicates that the trees on this serpentine soil generally suffered from multiple nutrient deficiencies and imbalances and the clonal variation in growth performance was more related to their capabilities of acclimation to nutrient than water stresses. Overall, the clones that absorbed more P, K, S, and Fe and less Mg from the soil grew better on this serpentine soil. For unimproved clones, the most limiting nutrients for tree growth were foliar K and Fe, while for improved clones it was foliar K.     

Influence of landscape structure on reef fish assemblages

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape.

     

Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez,Chile

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Coarse woody debris decay rates for seven indigenous tree species in the central North Island of New Zealand

The decomposition rate of stem and branch coarse woody debris (CWD, >10 cm in diameter) was assessed in natural forests located in the central North Island of New Zealand. CWD samples had originated from windfalls associated with cyclone Bernie, and had been decaying for approximately 20 years on the forest floor. Species-specific decay rates were estimated from the density of CWD samples relative to the density of live tree samples from the same stands. Decay rates were determined for rimu (Dacrydium cupressinum), matai (Prumnopitys taxifolia), tawa (Beilschmiedia tawa), miro (Prumnopitys ferruginea) and kahikatea (Dacrycarpus dacrydioides) in podocarp forest at Whirinaki, and red (Nothofagus fusca) and silver beech (Nothofagus menziesii) in beech forest at Kaimanawa. The average decay rate for these seven species, expressed as the time taken to lose 50% mass (t_1/2), was 30 years. Larger trees (90 cm diameter at breast height, dbh) decayed more slowly (t_1/2 = 38 years) than smaller trees (30 cm dbh; t_1/2 = 21 years). After adjustment for dbh, P. taxifolia (t_1/2 = 39 years), N. fusca (t_1/2 = 38 years), N. menziesii (t_1/2 = 31 years) and B. tawa (t_1/2 = 26 years) decayed significantly more slowly than D. cupressinum (t_1/2 = 18 years). D. cupressinum decayed more slowly than P. ferruginea (t_1/2 = 16 years) and D. dacrydioides (t_1/2 = 14 years), although these differences were not statistically significant because the CWD sample size was small for the latter two species. An attempt to expand the range of species studied using data from in-ground durability tests was not successful as species decay rankings from these tests were inconsistent with natural forest CWD rankings. Stems heavily colonized by the common decay fungus Ganoderma cf. applanatum decayed more rapidly (t_1/2 = 20 years) than those which were occupied only by other decay fungi (t_1/2 = 40 years). A tree species and dbh-dependent decay constant, λ, was derived for estimating carbon loss from CWD due to fungal decay and insect activity in indigenous forests. Future research will aim to improve these decay equations by investigating the decomposition processes associated with tree species and basidiomycete populations present at other sites in New Zealand.     

支持完整性决策的数据管理

大多数管道的运营、维护和其它设备管理部门,采用一系列各自独立的数据资源和应用程序来管理管道的完整性、维修和安全.将各个独立的数据整合成一个单一的、相互关联的数据管理系统可以提供很多重要的好处.然而,在给定管道早期投资的情况下,评价用于建立一个包含功能强大的数据采集程序在内的新系统的成本是非常困难的.采用静态的和独立的维护性数据的专用风险管理软件被作为一种快捷的、低成本的替代选择,以此来满足规章制度所规定的必须遵从的行业要求.通过开发传统数据等方法,以最小的启动成本来实现阶段性的完整性数据管理.     

Influence of landscape structure on reef fish assemblages

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape.