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61.
Rapid climate changes are currently driving substantial reorganizations of marine ecosystems around the world. A key question is how these changes will alter the provision of ecosystem services from the ocean, particularly from fisheries. To answer this question, we need to understand not only the ecological dynamics of marine systems, but also human adaptation and feedbacks between humans and the rest of the natural world. In this review, we outline what we have learned from research primarily in continental shelf ecosystems and fishing communities of North America. Key findings are that marine animals are highly sensitive to warming and are responding quickly to changes in water temperature, and that such changes are often happening faster than similar processes on land. Changes in species distributions and productivity are having substantial impacts on fisheries, including through changing catch compositions and longer distances traveled for fishing trips. Conflicts over access to fisheries have also emerged as species distributions are no longer aligned with regulations or catch allocations. These changes in the coupled natural-human system have reduced the value of ecosystem services from some fisheries and risk doing so even more in the future. Going forward, substantial opportunities for more effective fisheries management and operations, marine conservation, and marine spatial planning are likely possible through greater consideration of climate information over time-scales from years to decades.  相似文献   
62.
Two river-lake systems in a mosaic, lowland postglacial landscape (Masurian and Suwalskie Lakelands, northeastern Poland) of different length and flow were studied. The concentration of total and dissolved phosphorus (in water and in seston) and the retention of these two forms of P were analysed at several hydrological occasions in lakes of various morphometry and trophy, and in several stream fragments. The concentration and retention is equally highly variable in lake (lentic patches) and stream fragments (lotic patches) of the system. The polluted stream fragments at all occassions as well as the lakes in summer, are mainly exporting phoshorus. The patches which act as sources occur alternatively with patches which are P-sinks. This makes the whole system more or less balanced with respect to P movement in the landscape.  相似文献   
63.
Spring systems, whether natural or engineered, are composed of compliant and rigid regions. Biological springs are often similar to monolithic structures that distribute compliance and rigidity across the whole system. For example, to confer different amounts of compliance in distinct regions within a single structure, biological systems typically vary regional morphology through thickening or elongation. Here, we analyze the monolithic spring in mantis shrimp (Stomatopoda) raptorial appendages to rapidly acquire or process prey. We quantified the shape of cross‐sections of the merus segment of the raptorial appendage. We also examined specific regions of the merus that are hypothesized to either store elastic energy or provide structural support to permit energy storage in other regions of the system. We found that while all mantis shrimp contain thicker ventral bars in distal cross‐sections, differences in thickness are more pronounced in high‐impact “smasher” mantis shrimp than in the slower‐striking “spearer” mantis shrimp. We also found that spearer cross‐sections are more circular while those of smashers are more eccentric with elongation along the dorso‐ventral axis. The results suggest that the regional thickening of ventral bars provides structural support for resisting spring compression and also reduces flexural stiffness along the system's long axis. This multilevel morphological analysis offers a foundation for understanding the evolution and mechanics of monolithic systems in biology. J. Morphol. 276:1123–1135, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
64.
According to the current, widely accepted paradigm, the evolutionary transition from hermaphroditism toward separate sexes occurs in two successive steps: an initial, intermediate step in which unisexual individuals, male or female, sterility mutants coexist with hermaphrodites and a final step that definitively establishes dioecy. Two nonexclusive processes can drive this transition: inbreeding avoidance and reallocation of resources from one sexual function to the other. Here, we report results of controlled crosses between males and hermaphrodites in Phillyrea angustifolia, an androdioecious species with two mutually intercompatible, but intraincompatible groups of hermaphrodites. We observed different segregation patterns that can be explained by: (1) epistatic interactions between two unlinked diallelic loci, determining sex and mating compatibility, and (2) a mutation with pleiotropic effects: female sterility, full compatibility of males with both hermaphrodite incompatibility groups, and complete male‐biased sex‐ratio distortion in one of the two groups. Modeling shows that these mechanisms can explain the high frequency of males in populations of P. angustifolia and can promote the maintenance of androdioecy without requiring inbreeding depression or resource reallocation. We thus argue that segregation distortion establishes the right conditions for the evolution of cryptic dioecy and potentially initiates the evolution toward separate sexes.  相似文献   
65.
Variation in hippocampal neuroanatomy correlates well with spatial learning ability in mice. Here, we have studied both hippocampal neuroanatomy and behavior in 53 isogenic BXD recombinant strains derived from C57BL/6J and DBA/2J parents. A combination of experimental, neuroinformatic and systems genetics methods was used to test the genetic bases of variation and covariation among traits. Data were collected on seven hippocampal subregions in CA3 and CA4 after testing spatial memory in an eight‐arm radial maze task. Quantitative trait loci were identified for hippocampal structure, including the areas of the intra‐ and infrapyramidal mossy fibers (IIPMFs), stratum radiatum and stratum pyramidale, and for a spatial learning parameter, error rate. We identified multiple loci and gene variants linked to either structural differences or behavior. Gpc4 and Tenm2 are strong candidate genes that may modulate IIPMF areas. Analysis of gene expression networks and trait correlations highlight several processes influencing morphometrical variation and spatial learning.  相似文献   
66.
The paper analyses the current limitations of the constraints of decision and action processes in land-use, resource management and conservation policies and approaches, identifying their main factors, proposing alternative strategies to solve the present gaps and limitations. It identifies the need for a new paradigmatic approach based on innovative forms of involvement, commitment and individual and community rewarding systems. This approach is developed based on the characterization of the main drivers of land-use, resource management and conservation policies, namely α-perceptions (immediate and primary satisfaction) and k-perceptions (more mediate and complex consideration of satisfaction, implying long-term perceptions and collective benefits beyond the individual interests). It also analyses the effects of the introduction of new forms of income and incentives (such as trade-offs and payments for environmental services) or management approaches such as Ecological-Based Management or the use of Nature-Based Solutions. The main axioms and instruments necessary to build such a new paradigmatic approach (namely trade-offs, accountability and contractualization) are described. On this basis, it is possible to present a concept for an innovative institutional and social culture and a governance system aimed at an effective land-use, resource management and conservation policies. This governance concept is described and its sustaining individual, social and institutional drivers enunciated.  相似文献   
67.
Sinusoidal oscillation transmission through branched metabolic pathways is studied. Two systems are analyzed, which are composed of two convergent reaction branches and differ in the length of one of them. Linear kinetics is assumed first. Michaelis-Menten enzymes are then considered by using previous results that suggest their behavior with respect to propagation of oscillations is close to linearity around the mean input flux. As a result, there exist ways to modulate the activity of the enzymes so that propagation is equivalent for branched and specific unbranched pathways. Cells may have taken advantage of such a possibility in cases where oscillations have a biological role.  相似文献   
68.
Research into the design and utilization of brain-implanted microdevices, such as microelectrode arrays, aims to produce clinically relevant devices that interface chronically with surrounding brain tissue. Tissue surrounding these implants is thought to react to the presence of the devices over time, which includes the formation of an insulating "glial scar" around the devices. However, histological analysis of these tissue changes is typically performed after explanting the device, in a process that can disrupt the morphology of the tissue of interest.Here we demonstrate a protocol in which cortical-implanted devices are collected intact in surrounding rodent brain tissue. We describe how, once perfused with fixative, brains are removed and sliced in such a way as to avoid explanting devices. We outline fluorescent antibody labeling and optical clearing methods useful for producing an informative, yet thick tissue section. Finally, we demonstrate the mounting and imaging of these tissue sections in order to investigate the biological interface around brain-implanted devices.  相似文献   
69.
70.
Forest conservation strategies and plans can be unsuccessful if the new habitat conditions determined by climate change are not considered. Our work aims at investigating the likelihood of future suitability, distribution and diversity for some common European forest species under the projected changes in climate, focusing on Southern Europe. We combine an Ensemble Platform for Species Distribution Models (SDMs) to five Global Circulation Models (GCMs) driven by two Representative Concentration Pathways (RCPs), to produce maps of future climate‐driven habitat suitability for ten categories of forest species and two time horizons. For each forest category and time horizon, ten maps of future distribution (5 GCMs by 2 RCPs) are thus combined in a single suitability map supplied with information about the “likelihood” adopting the IPCC terminology based on consensus among projections. Then, the statistical significance of spatially aggregated changes in forest composition at local and regional level is analyzed. Finally, we discuss the importance, among SDMs, that environmental predictors seem to have in influencing forest distribution. Future impacts of climate change appear to be diversified across forest categories. A strong change in forest regional distribution and local diversity is projected to take place, as some forest categories will find more suitable conditions in previously unsuitable locations, while for other categories the same new conditions will become less suited. A decrease in species diversity is projected in most of the area, with Alpine region showing the potentiality to become a refuge for species migration.  相似文献   
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