Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Developing and integrating enhancement strategies to improve and restore fisheries

Fisheries enhancements are management approaches involving the use of aquaculture and habitat technologies (in the broadest sense) to enhance or restore fisheries. The technologies most commonly used include hatchery rearing and release of aquatic animals and provision of artificial structures such as artificial reefs. Both are associated with distinct fields of knowledge and communities of practice. Recent calls to expand and broaden the role of aquaculture and habitat enhancements in marine conservation and an increasingly integrated view of living marine resource management have led to an aspirational broadening of concepts in this area. The 10th William R and Lenore Mote Symposium and 6 th International Symposium on Stock Enhancement and Sea Ranching aimed to advance and integrate knowledge across enhancement technologies and practices. Substantial progress was noted in multiple technical areas such as understanding the potential and limitations for rearing organisms fit for release into the wild, and the design of artificial reefs to enhance local fish abundance. Crucial higher-level goals such as effectively enhancing or restoring fish abundance and fisheries at the stock level continue to receive insufficient attention across the enhancement sciences. Integration of enhancement strategies provides opportunities and challenges including a need to recognize, cross-discover, and engage other distinct areas of knowledge and communities of practice. A quick reference guide is provided to facilitate this process

Evolving context and maturing science: Aquaculture-based enhancement and restoration enter the marine fisheries management toolbox

Aquaculture-based enhancement of marine fisheries includes sea ranching, stock enhancement, and restocking. A rapidly evolving context and maturing science base have effectively put these approaches into the fisheries management toolbox. Among the contextual factors are (1) a rapid expansion of captive breeding and domestication to new marine species, (2) fisheries governance systems that address the common dilemma, and (3) global environmental change impacts on coastal fisheries that increasingly call for active approaches to maintaining or increasing fisheries yields and ecosystem services. The science base of marine restocking, stock enhancement, and sea ranching continues to advance rapidly and has now reached a point where it is becoming possible to assess the likely contribution of such approaches to fisheries management goals prior to major investments being undertaken and to design enhancement programs effectively and responsibly where good potential is judged to exist. This signifies an important transition of marine fisheries enhancement from an exploratory, research-oriented endeavor to a tool in the fisheries management tool box

Fisheries enhancement and restoration in a changing world

Fisheries enhancement is an important strategy for maintaining and improving fisheries productivity, and addressing some of the other contemporary challenges facing marine ecosystems. Aquaculture-based enhancement includes stock enhancement, restocking, and sea ranching. Developments in aquaculture techniques, tagging, genetics, modelling and ecology have underpinned growth in this field in the 21st century, particularly in the context of marine recreational fisheries. Marine enhancement practice has now matured to the point that quantitative tools are frequently applied before any fish or shellfish are released into the natural environment, and pilot-scale enhancement scenarios and release strategies are evaluated before full implementation. Social and economic studies are also increasingly important components of this assessment. Here, several case studies from diverse geographic areas exemplify the union of aquaculture technology, quantitative modelling, social science, physiology and ecology to estimate enhancement potential, improve enhancement strategies, assess enhancement outcomes, and support adaptive management. Integrating aquaculture-based enhancement with habitat enhancement presents a remarkable opportunity for future research and development, and offers the potential to further increase the opportunities and associated socio-economic benefits that are available to a broad range of fisheries stakeholder

Regressive evolution of an eye pigment gene in independently evolved eyeless subterranean diving beetles

Regressive evolution, the reduction or total loss of non-functional characters, is a fairly common evolutionary phenomenon in subterranean taxa. However, the genetic basis of regressive evolution is not well understood. Here we investigate the molecular evolution of the eye pigment gene cinnabar in several independently evolved lineages of subterranean water beetles using maximum likelihood analyses. We found that in eyeless lineages cinnabar has an increased rate of sequence evolution, as well as mutations leading to frame shifts and stop codons, indicative of pseudogenes. These results are consistent with the hypothesis that regressive evolution of eyes proceeds by random mutations, in the absence of selection, that ultimately lead to the loss of gene function in protein-coding genes specific to the eye pathway