Theoretical insight into three disease-related benefits of migration

Migration (seasonal round-trip movement across relatively large distances) is common within the animal kingdom. This behaviour often incurs extreme costs in terms of time, energy, and/or survival. Climate, food, predation, and breeding are typically suggested as factors favouring the evolution of migration. Although disease regulation has also been considered, few studies consider it as the primary selective pressure for migration. Our aim was to determine, theoretically, under what conditions migration could reduce the long-term disease prevalence within a population, assuming the only benefits of migration are infection-related. We created two mathematical models, one where the population migrates annually and one where the entire population remains on the breeding ground year-round. In each we simulated disease transmission (frequency-dependent and density-dependent) and quantified eventual disease prevalence. In the migration model we varied the time spent migrating, disease-related migration mortality, and the overall migration mortality. When we compared results from the two models, we found that migration generally lowered disease prevalence. We found a population was healthier if it: (1) spent more time migrating (assuming no disease transmission during migration), (2) had higher disease-induced migration mortality, and (3) had an overall higher mortality when migrating (compared to not migrating). These results provide support for two previously proposed mechanisms by which migration can reduce disease prevalence (migratory escape and migratory cull), and also demonstrate that non-selective mortality during migration is a third mechanism. Our findings indicate that migration may be evolutionarily advantageous even if the only migratory benefit is disease control.     

Midpoint attractors and species richness: Modelling the interaction between environmental drivers and geometric constraints

We introduce a novel framework for conceptualising, quantifying and unifying discordant patterns of species richness along geographical gradients. While not itself explicitly mechanistic, this approach offers a path towards understanding mechanisms. In this study, we focused on the diverse patterns of species richness on mountainsides. We conjectured that elevational range midpoints of species may be drawn towards a single midpoint attractor – a unimodal gradient of environmental favourability. The midpoint attractor interacts with geometric constraints imposed by sea level and the mountaintop to produce taxon‐specific patterns of species richness. We developed a Bayesian simulation model to estimate the location and strength of the midpoint attractor from species occurrence data sampled along mountainsides. We also constructed midpoint predictor models to test whether environmental variables could directly account for the observed patterns of species range midpoints. We challenged these models with 16 elevational data sets, comprising 4500 species of insects, vertebrates and plants. The midpoint predictor models generally failed to predict the pattern of species midpoints. In contrast, the midpoint attractor model closely reproduced empirical spatial patterns of species richness and range midpoints. Gradients of environmental favourability, subject to geometric constraints, may parsimoniously account for elevational and other patterns of species richness.     

A life‐history perspective on the demographic drivers of structured population dynamics in changing environments

Current understanding of life‐history evolution and how demographic parameters contribute to population dynamics across species is largely based on assumptions of either constant environments or stationary environmental variation. Meanwhile, species are faced with non‐stationary environmental conditions (changing mean, variance, or both) created by climate and landscape change. To close the gap between contemporary reality and demographic theory, we develop a set of transient life table response experiments (LTREs) for decomposing realised population growth rates into contributions from specific vital rates and components of population structure. Using transient LTREs in a theoretical framework, we reveal that established concepts in population biology will require revision because of reliance on approaches that do not address the influence of unstable population structure on population growth and mean fitness. Going forward, transient LTREs will enhance understanding of demography and improve the explanatory power of models used to understand ecological and evolutionary dynamics.     

Translating niche features: Modelling differential exposure of Argentine reptiles to global climate change

Global climate change affects the distributions of ectotherms and may be the cause of several conservation problems, such as great displacement of climatic suitable spaces for species and, consequently, important reductions of the extent of liveable places, threatening the existence of many of them. Species exposure (and hence vulnerability) to global climate change is linked to features of their climatic niches (such as the relative position of the inhabited localities of each species in the climatic space), and therefore to characteristics of their geographic ranges (such as the extent of the distributions or altitudinal range inhabited by the species). In order to analyze the pattern of response of Argentine reptiles to global climate change, we ran phylogenetic generalized least squares models using species exposure to global climate change as a response variable, and (i) niche properties (breadth and position of the species in the climate space) and (ii) general features of the distribution of species (maximum latitude, altitudinal range, maximum elevation, distributional range and proximity to the most important dispersal barrier) as predictors. Our results suggest that the best way to explain climate change exposure is by combining breadth and position of climatic niche of the species or combining geographic features that are indicators of both niche characteristics. Our best model shows that in our study area, species with the narrowest distributional ranges that also inhabit the highest elevations are the most exposed to the effects of global climate change. In this sense, reptile species from Yungas, Puna and Andes ecoregions could be especially vulnerable to the effects of climate change. We believe that these types of models may represent an interesting tool for determining species and places particularly threatened by the effects of global climate change, which should be strongly considered in conservation planning.     

Acoustic sequences in non‐human animals: a tutorial review and prospectus

Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well‐known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near‐future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial‐style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.     

The Regulatory Status of Genome‐edited Crops

Genome editing with engineered nucleases (GEEN) represents a highly specific and efficient tool for crop improvement with the potential to rapidly generate useful novel phenotypes/traits. Genome editing techniques initiate specifically targeted double strand breaks facilitating DNA‐repair pathways that lead to base additions or deletions by non‐homologous end joining as well as targeted gene replacements or transgene insertions involving homology‐directed repair mechanisms. Many of these techniques and the ancillary processes they employ generate phenotypic variation that is indistinguishable from that obtained through natural means or conventional mutagenesis; and therefore, they do not readily fit current definitions of genetically engineered or genetically modified used within most regulatory regimes. Addressing ambiguities regarding the regulatory status of genome editing techniques is critical to their application for development of economically useful crop traits. Continued regulatory focus on the process used, rather than the nature of the novel phenotype developed, results in confusion on the part of regulators, product developers, and the public alike and creates uncertainty as of the use of genome engineering tools for crop improvement.     

Optimal conservation planning of multiple hydrological ecosystem services under land use and climate changes in Teshio river watershed,northernmost of Japan

Most anthropogenic activities impacted on water quality and quantity, and further impacted on ecosystem services (ESs) in watershed are related to land use and climate changes those may cause losses of ecosystem functions. Effective information regarding ESs and their optimal priority conservation planning responded to land use and climate changes provide useful support for diverse stakeholders in ESs planning, management and policies. This study integrated the approach of spatially explicit ESs (water yield, inorganic nutrient, organic nutrient and sediment retentions) by using hydrology and material flow model (Soil and Water Assessment Tools, SWAT model) into systematic conservation of hydrological ESs according to land use and climate changes in Teshio watershed located in the north of Hokkaido, Japan. We investigated the spatial patterns and the hotspots of ESs changes to determine the spatial pattern of changes in systematic conservation optimal area of ES protection in terms of ESs protection targets. Under the land use and climate change scenarios, the forest land use significantly affected on the water yield, sediment, organic-Nitrogen (N) and organic-Phosphorous (P) retentions. The agricultural land (paddy and farmland fields) impacted on the inorganic-N and inorganic-P retentions. We applied the systematic conservation model (MARXAN model) to optimize the area for management of hydrological ESs satisfied the protection targets (30% and 50% of potential maximum ESs values among all scenarios) in all and individual ecosystem services, respectively. The simulated results indicated that the areas of spatial optimal ESs protection for all hydrological ESs were totally different from those for individual ESs. For bundles of ESs, the optimal priority conservation areas concentrated in southwest, north, and southeast of this watershed, which are related to land use, topography and climate driving factors. These places could guarantee ESs sustainability from both environmental protection and agricultural development standpoints. The priority conservation area turned more compact under climate change because the increased precipitation and temperature increased ESs amount. For individual ESs, the optimal priority conservation areas of water yield, sediment retention and organic nutrient retention were traded off against those of inorganic nutrient retention (lower Jaccard's indexes and negative correlations of selection times). Especially, the negative correlation of selection times increased as the conservation target increased from 30% to 50%. The proposed approach provided useful information for assessing the responses of ESs and systematic conservation optimal planning to the land use and climate changes. The systematic conservation optimal areas of hydrological ESs provided an effective trade-off tool between environmental protection (sediment and organic nutrient retentions) and economic development (water yield and inorganic nutrient retention).     

Evaluating ecosystem-level anthropogenic impacts in a stressed transitional environment: The case of the Seine estuary

During 2002–2005, a new container terminal in the commercial harbour of Le Havre, named “Port2000”, was built on the northern flank of the Seine estuary, northern France. This extension is already known to have modified the estuary current and sediment dynamics, as well as reducing biomass of the suprabenthos assemblage, for the whole downstream part of the system. However, studies on other biotic communities were largely inconclusive, and an ecosystem-wide analysis was still lacking. Here, we performed a before/after study of ecosystem dynamics of the different habitats of the Seine estuary, using a Linear Inverse Modelling technique (LIM-MCMC) to estimate all flows occurring in the food web. Ecological Network Analysis indices were calculated, summarising ecosystem functioning traits and giving indications about the habitat health status. Results showed that the southern flank (FS, Fosse Sud) exhibits all characteristics to be considered as the least stressed habitat of the estuary: system activity and functional specialisation of flows were stable between periods, ecosystem recycling processes and detrital dynamics were also stable; an increase in trophic specialisation (decrease in system omnivory) was the only change confirming a general ecological succession. The northern flank (FN, Fosse Nord), where the actual terminal was built, showed a food web with increased importance of lower trophic levels (increased detritivory and carbon recycling), increased stability and flow efficiency, but possibly regressed to a previous step in ecological succession. In the central navigation channel (CH), patterns of network indices were overall inconclusive and the general image is one of a constantly shifting food web, a condition possibly caused by the year-round dredging activities. The functioning of the Seine estuary – especially of FN and FS – seems to have been modified by the combination of harbour construction and the related mitigation measures. Network indices partially captured this combination of changes and, although not fully operational yet, they are promising tools to comply with the European Union mandate of defining ecosystem health status.     

Inter-regional linkage analysis of industrial CO2 emissions in China: An application of a hypothetical extraction method

As the largest CO₂ emitter in the world, China has faced great pressure to mitigate its CO₂ emissions. Thus, issues related to CO₂ emissions in China have been widely studied. However, the industrial linkages of CO₂ emissions at the regional level have been less concerned. This study integrates hypothetical extraction method with the multi-regional input–output model, and investigates industrial CO₂ emission linkages of China at the regional level. Based on the data of China in 2007, which decomposes China into eight regions, this study first analyzes the production-based emission (PBE) and consumption-based emission (CBE) of each region. The PBE and CBE of 10 branches are then analyzed and decomposed into three parts. Finally, this study decomposes the externally produced embodied emission (EPEE) and internally produced embodied emission (IPEE) of Petrochemicals and Minerals in the East Coast, to illustrate how these two indicators of a branch affect other branches in the economy. Results show that regions with large PBE, such as coastal regions and Central, usually have large CBE, whereas Jing-jin has the smallest PBE and CBE. Branches such as Mining and Petrochemicals and Minerals, have large PBE and are net CO₂ emission exporters; while Construction and Other Services are net importers. According to the decomposition results of PBE and CBE, branches can be classified into four groups. The decomposed IPEE and EPEE of Petrochemicals and Minerals in the East Coast show that from the perspective of regions, CO₂ emissions this branch exports to and imports from East Coast are most. From the perspective of branches, decomposition of IPEE shows that Petrochemicals and Minerals in the East Coast exports a large amount of CO₂ emissions to Construction, while the decomposition results of EPEE show that the studied branch imports least CO₂ emissions from Construction. Policy implications deduced from this study are discussed.