BackgroundThe dynamic geological and climatic histories of temperate South America have played important roles in shaping the contemporary distributions and genetic diversity of endemic freshwater species. We use mitochondria and nuclear sequence variation to investigate the consequences of mountain barriers and Quaternary glacial cycles for patterns of genetic diversity in the diadromous fish Galaxias maculatus in Patagonia (~300 individuals from 36 locations).ResultsContemporary populations of G. maculatus, east and west of the Andes in Patagonia, represent a single monophyletic lineage comprising several well supported groups. Mantel tests using control region data revealed a strong positive relationship when geographic distance was modeled according to a scenario of marine dispersal. (r = 0.69, P = 0.055). By contrast, direct distance between regions was poorly correlated with genetic distance (r = -0.05, P = 0.463). Hierarchical AMOVAs using mtDNA revealed that pooling samples according to historical (pre-LGM) oceanic drainage (Pacific vs. Atlantic) explained approximately four times more variance than pooling them into present-day drainage (15.6% vs. 3.7%). Further post-hoc AMOVA tests revealed additional genetic structure between populations east and west of the Chilean Coastal Cordillera (coastal vs. interior). Overall female effective population size appears to have remained relatively constant until roughly 0.5 Ma when population size rapidly increased several orders of magnitude [100× (60×-190×)] to reach contemporary levels. Maximum likelihood analysis of nuclear alleles revealed a poorly supported gene tree which was paraphyletic with respect to mitochondrial-defined haplogroups.ConclusionsFirst diversifying in the central/north-west region of Patagonia, G. maculatus extended its range into Argentina via the southern coastal regions that join the Pacific and Atlantic oceans. More recent gene flow between northern populations involved the most ancient and most derived lineages, and was likely facilitated by drainage reversal(s) during one or more cooling events of the late Pleistocene. Overall female effective population size represents the end result of a widespread and several hundred-fold increase over approximately 0.5 Ma, spanning several climatic fluctuations of the Pleistocene. The minor influence of glacial cycles on the genetic structure and diversity of G. maculatus likely reflects the access to marine refugia during repeated bouts of global cooling. Evidence of genetic structure that was detected on a finer scale between lakes/rivers is most likely the result of both biological attributes (i.e., resident non-migratory behavior and/or landlocking and natal homing in diadromous populations), and the Coastal Cordillera as a dispersal barrier.

Food availability and predation risk have been shown to affect phenotypes during early life history of fishes. Galaxias maculatus, a small fish widely distributed around the southern hemisphere, clearly exhibits a complex trade-off between feeding and predation avoidance during growth over the larval period. We studied the effect of different environmental variables on diet, growth, mortality, and morphology through field surveys and data revision in the literature for limnetic G. maculatus larvae in five oligotrophic lakes of Patagonia. Both number of food categories and prey ingested by larvae were directly related to zooplankton density. Larval growth rate was related with zooplankton density and temperature. Lakes with high zooplankton densities and low predation risk had larvae with deeper bodies and shorter caudal peduncles, while in lakes with less food and high predation risk larvae were slender with shallower bodies and longer peduncles. Food availability and predation risk seem to operate on the swimming performance of G. maculatus larvae through the slenderness of the body and the length of the caudal peduncle. The observed phenotypic variation in growth and morphology could be a key feature that has allowed this species to successfully colonize a wide variety of environments in the southern hemisphere.

Summary 1. Understanding the influence of landscape characteristics on genetic and phenotypic intraspecific variability can yield insights into how evolutionary processes work as well as provide essential information for the conservation of biodiversity. 2. Our aim was to compare the genetic structure and phenotypic variation among Galaxias maculatus populations inhabiting two Atlantic Ocean river basins in Patagonia in relation to historical and contemporary landscape characteristics associated with latitude. 3. Population genetic analysis (based on eight microsatellite loci, 505 individuals) indicates that genetic structure is more pronounced in the Río Negro basin (RN) at 39–41°S (10 localities) than in the southernmost Santa Cruz River basin (SCR) at 49–50°S (seven localities). Spatial autocorrelation analysis showed different effects of geographic distance in shaping population differentiation patterns in the two basins. 4. While in northern Patagonia, fragmented populations could have survived the severity of Quaternary climate cycles, at higher latitudes G. maculatus populations were probably extirpated by extensive ice sheets. Extant populations in the upper reaches of the southernmost basin probably originated from refugia close to the Atlantic Ocean. 5. Based on otolith microchemistry, we have documented facultative diadromy for the first time for the species in the SCR basin, while no evidence of migration to the sea was found in individuals from the RN basin. Vertebral number increased with latitude, and within the SCR basin, the higher counts are possibly associated with a migratory life style.

Understanding the influence of landscape features on population differentiation is fundamental to evolutionary biology studies. We examined spatial patterns of genetic and phenotypic variability among Galaxias maculatus populations in a complex of four postglacial lakes in northwestern Patagonia differing in size and connectivity among them. A hierarchical Bayesian analysis grouped the individuals collected from eleven localities into three genetic clusters, first defining the populations of the two large lakes and separating the two small lakes in subsequent analysis. Genetic structuring was restricted within large lakes. It is known that the larval stage of Galaxias maculatus migrate to the limnetic zone of Patagonian lakes, possibly exerting an homogenizing effect on gene flow within lakes. Gene flow asymmetry and divergences among lakes can be explained by a combination of landscape characteristics and the presence of predators in the short streams that connect them. Individuals from the small lakes are the most divergent morphologically and genetically. The population in the isolated Redonda Lake, exhibits meristic differences as well, suggesting strong drift and environmental effects. This population is likely to have been isolated following the decline in water level of a paleolake that existed in this region approximately 13.2 kya BP. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

Aim Historical connectivity between drainages may represent an underappreciated contributor to the biodiversity within a catchment. First, we tested whether an isolated population of freshwater-limited galaxiids represents a contribution by past interdrainage connectivity to this system's biodiversity, rather than reflecting intracatchment dispersal or speciation. Second, we sought to distinguish between possible geomorphic processes that could have allowed any past connectivity.Location The Clutha and adjacent Southland region drainages on the South Island of New Zealand.Methods We estimated the phylogeographical relationships among 466 cytochrome b sequences from 'roundhead' Galaxias populations throughout the Southland region and the Clutha drainage, using three different methods. Subsequently, possible geomorphic mechanisms of interdrainage connectivity were examined concurrently with genetic population divergence time estimates obtained by coalescent analysis.Results All samples obtained in the lower Clutha system were genetically attributable to G. gollumoides and reflected at least a third, independent colonization event from Southland involving this species, rather than intradrainage dispersal or speciation by pre-existing Clutha populations. Geomorphological inferences and divergence time estimates of less than 7 ka are consistent with headwater connections across low divides between the lower Clutha and the Catlins region of Southland, rather than anastomosing of main channels during low sea stands. Main conclusionsThe observation of at least three interdrainage connectivity events influencing the diversity and distribution of G. gollumoides lineages within the Clutha system highlights the potential significance of these processes as contributors to the magnitude and distribution of biodiversity within catchments.

This article documents the addition of 473 microsatellite marker loci and 71 pairs of single-nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Barteria fistulosa, Bombus morio, Galaxias platei, Hematodinium perezi, Macrocentrus cingulum Brischke (a.k.a. M. abdominalis Fab., M. grandii Goidanich or M. gifuensis Ashmead), Micropogonias furnieri, Nerita melanotragus, Nilaparvata lugens Stål, Sciaenops ocellatus, Scomber scombrus, Spodoptera frugiperda and Turdus lherminieri. These loci were cross-tested on the following species: Barteria dewevrei, Barteria nigritana, Barteria solida, Cynoscion acoupa, Cynoscion jamaicensis, Cynoscion leiarchus, Cynoscion nebulosus, Cynoscion striatus, Cynoscion virescens, Macrodon ancylodon, Menticirrhus americanus, Nilaparvata muiri and Umbrina canosai. This article also documents the addition of 116 sequencing primer pairs for Dicentrarchus labrax.

Aims: Pleistocene glacial cycles have had profound effects on the distribution and genetic diversity of high latitude species, which can vary with species-specific traits, such as vagility. Demographic responses of antarctic flying seabirds to the same events remain unassessed. We addressed this knowledge gap by studying the genetic population connectivity and demographic history of a flying seabird endemic to Antarctica, the Snow petrel. We hypothesize that their high vagility due to flight may represent an advantage over non-flying seabirds in enduring past climate variation.Location: Approximately 3,000 km of coastline in East Antarctica, covering three areas in Mac. Robertson Land, Princess Elizabeth Land and Wilkes Land. An inland location was also sampled at the Prince Charles Mountains, Mac. Robertson Land.Taxon: Snow petrel (Pagodroma nivea). Methods:We sampled 93 individuals and sequenced a total of 5,412 base pairs, including two mitochondrial genes, four anonymous nuclear loci and a nuclear intron. We used frequentist and Bayesian approaches to examine population genetic structuring and an Extended Bayesian Skyline Plot method to infer the demographic history of the species in the study area. In addition, evidence of exposed bedrock during glacial periods was summarized in maps of the studied area representing potential refugia for the species.Results: Differentiation indexes, genetic clustering and haplotype networks suggest long-term population connectivity for Snow petrels across the study area, with no evidence for reliction into refugia that were genetically isolated. Significantly, population expansions pre-dated the Last Glacial Maximum (LGM), but only where there was evidence of ice-free areas during this period. Main conclusions:The high vagility of Snow petrels may have been advantageous for access to foraging areas and supported large populations despite the harsh conditions during the LGM. Our results highlight that species-specific traits can exert a strong influence on demographic responses to the same environmental events.

The purpose of this review is to describe how health service and delivery systems support health equity, and to identify strategies and indicators being used to measure health equity. Introduction:It is widely acknowledged that a population health and equity approach is needed to improve the overall health of the population. The health service and delivery system plays an important role in this approach. Despite this, system transformation to address health inequities has been slow. This is due, in part, to the lack of evidence-based guidance on how health service and delivery systems can address and measure health equity integration. Most studies focus on health equity integration in the public health sector at a provincial or national level, but less is known about integration within the health service and delivery system. More information is needed to understand how that transformation is occurring, or could occur, to make a meaningful contribution toward improving population health outcomes.Inclusion criteria: This scoping review will identify studies that describe the strategies and indicators that health service and delivery systems are using to integrate health equity and how progress is measured. Evidence from qualitative, quantitative, mixed method studies, and gray literature will be included.Methods: This review will be conducted in accordance with JBI methodology for scoping reviews. A comprehensive search strategy, developed with a librarian scientist, will be used to identify relevant sources. Titles, abstracts, and full texts will be evaluated against inclusion criteria. Information will be extracted by two independent reviewers. Data will be synthesized and presented narratively, with tables and figures where appropriate.