Molecular cloning and characterization of six novel HMW‐GS genes from Aegilops speltoides and Aegilops kotschyi

Six novel high molecular weight glutenin subunits (HMW‐GS) from Aegilops speltoides (SS, 2n = 2x = 14) and Aegilops kotschyi (UUSS, 2n = 4x = 28) were identified by SDS‐PAGE and designated as ASy15*, AKx1*, AKx3*, AKx2.3, AKy20* and AKy8*, respectively. Their complete open reading frames (ORFs) were cloned and sequenced by allele‐specific PCR (AS‐PCR). Sequence comparison demonstrated that these novel genes displayed high single‐nucleotide polymorphisms (SNP) and InDel variations. In particular, AKy8* had an extra cysteine residue at position 140 in the central repetitive domain, while AKx2.3 had an unusually long repetitive domain (816 aa), which might have positive effects on gluten quality. Phylogenetic analysis showed that AKx1* and AKx3* belonged to the 1S genome, AKx2.3 to the 1U genome, and AKy20* and AKy8* most likely to the 1S genome. The divergence between the 6 HMW‐GS genes from the two Aegilops species and those from Triticum species occurred 4.77–23.54 MYA. The authenticity of these isolated endogenous HMW‐GS genes was confirmed through heterologous expression in Escherichia coli and Western blotting.     

China's distant‐water fisheries in the 21st century

We conservatively estimate the distant‐water fleet catch of the People's Republic of China for 2000–2011, using a newly assembled database of reported occurrence of Chinese fishing vessels in various parts of the world and information on the annual catch by vessel type. Given the unreliability of official statistics, uncertainty of results was estimated through a regionally stratified Monte Carlo approach, which documents the presence and number of Chinese vessels in Exclusive Economic Zones and then multiplies these by the expected annual catch per vessel. We find that China, which over‐reports its domestic catch, substantially under‐reports the catch of its distant‐water fleets. This catch, estimated at 4.6 million t year^?1 (95% central distribution, 3.4–6.1 million t year^?1) from 2000 to 2011 (compared with an average of 368 000 t·year^?1 reported by China to FAO), corresponds to an ex‐vessel landed value of 8.93 billion € year^?1 (95% central distribution, 6.3–12.3 billion). Chinese distant‐water fleets extract the largest catch in African waters (3.1 million t year^?1, 95% central distribution, 2.0–4.4 million t), followed by Asia (1.0 million t year^?1, 0.56–1.5 million t), Oceania (198 000 t year^?1, 144 000–262 000 t), Central and South America (182 000 t year^?1, 94 000–299 000 t) and Antarctica (48 000 t year^?1, 8 000–129 000 t). The uncertainty of these estimates is relatively high, but several sources of inaccuracy could not be fully resolved given the constraints inherent in the underlying data and method, which also prevented us from distinguishing between legal and illegal catch.     

Fate of nitrogen released from 15N-labeled litter in European beech forests

The decomposition and fate of 15N-labeled beech litter was monitored in three European beech (Fagus sylvatica L.) forests (Aubure, France; Ebrach, Germany; and Collelongo, Italy) for 3 years. Circular plots around single beech trees were isolated from roots of neighboring trees by soil trenching, and annual litterfall was replaced by 15N-labeled litter. Nitrogen was continuously released from the decomposing litter. However, over a 2-year period, this release was balanced by the incorporation of exogenous N. Released N accumulated mainly at the soil surface and in the topsoil. Microbial biomass remained almost constant during the experiment at all sites except for considerably lower values at Ebrach. The 15N enrichment of the microbial biomass increased strongly during the first year and then remained stable. The 15N released from the decomposing litter was rapidly detected in roots and leaves of the beech trees, increasing regularly and linearly over the course of the experiment. The uptake of litter-released 15N by the trees was reduced under conditions that reduced tree growth. Under these conditions, leaves and fine roots were the dominant N sinks, and little N was allocated to other plant parts. By contrast, N uptake and N allocation from leaves to stem and bark tissues increased when tree growth was enhanced. Budgets for 15N showed that 2 to 4% of litter-released N was incorporated into the trees, about 35% remained in the litter and about 50% reached the topsoil.     

13C and 15N isotopic fractionation in trees, soils and fungi in a natural forest stand and a Norway spruce plantation

¹⁵N and ¹³C natural abundances of foliage, branches, trunks, litter, soil, fungal sporophores, mycorrhizas and mycelium were determined in two forest stands, a natural forest and a Norway spruce plantation, to obtain some insights into the role of the functional diversity of saprotrophic and ectomycorrhizal fungi in carbon and nitrogen cycles. Almost all saprotrophic fungi sporophores were enriched in ¹³C relative to their substrate. In contrast, they exhibited no or very little shift of δ¹⁵N. Judging from the amount of C discrimination, ectomycorrhizal fungi seem to acquire carbon from their host or from dead organic matter. Some ectomycorrhizal species seem able to acquire nitrogen from dead organic matter and could be able to transfer it to their host without nitrogen fractionation, while others supply their host with ¹⁵N-depleted nitrogen. Moreover ectomycorrhizal species displayed a significant N fractionation during sporophore differentiation, while saprotrophic fungi did not.     

Multi-scale habitat selection modeling: a review and outlook

Context

Scale is the lens that focuses ecological relationships. Organisms select habitat at multiple hierarchical levels and at different spatial and/or temporal scales within each level. Failure to properly address scale dependence can result in incorrect inferences in multi-scale habitat selection modeling studies.

Objectives

Our goals in this review are to describe the conceptual origins of multi-scale habitat selection modeling, evaluate the current state-of-the-science, and suggest ways forward to improve analysis of scale-dependent habitat selection.

Methods

We reviewed more than 800 papers on habitat selection from 23 major ecological journals published between 2009 and 2014 and recorded a number of characteristics, such as whether they addressed habitat selection at multiple scales, what attributes of scale were evaluated, and what analytical methods were utilized.

Results

Our results show that despite widespread recognition of the importance of multi-scale analyses of habitat relationships, a large majority of published habitat ecology papers do not address multiple spatial or temporal scales. We also found that scale optimization, which is critical to assess scale dependence, is done in less than 5 % of all habitat selection modeling papers and less than 25 % of papers that address “multi-scale” habitat analysis broadly defined.

Conclusions

Our review confirms the existence of a powerful conceptual foundation for multi-scale habitat selection modeling, but that the majority of studies on wildlife habitat are still not adopting multi-scale frameworks. Most importantly, our review points to the need for wider adoption of a formal scale optimization of organism response to environmental variables.