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Anadromous, resident, and landlocked Arctic char (Salvelinus alpinus) differentially experience drift and gene flow, making them ideal for studying incipient divergence. We investigated genetic divergence within and among char occupying landlocked and sea-accessible sites in Labrador, Canada, using 11 microsatellites. Unlike anadromous char, landlocked char were highly genetically differentiated. Genetic subgroups were detected within landlocked and sea-accessible sites. Within Ramah Lake (a sea-accessible site containing two subgroups), one subgroup matured at a small size, and both subgroups had equal proportions of males to females. These findings refute residency as a sneaker male tactic and instead suggest the presence of reproductively isolated resident and anadromous char. Subgroups demonstrated equal frequencies of Atlantic and Arctic lineage mtDNA haplotypes, suggesting their genetic differences were not due to allopatry during the last glacial maximum. Our results are therefore consistent with the sympatric genetic divergence of resident and anadromous Arctic char morphs.

Although more than a decade has passed since the imperative to reduce fragmentation of care, high rehospitalization rates among Medicare patients with chronic diseases persist; at least 25% of these are considered preventable. Transitional care models that emphasize coordination among providers have demonstrated significant reductions in hospitalization rates. However, achieving effective collaboration among providers across disciplines and/or facilities through implementation of transitional care models can be challenging.The aims of this article are to (1) describe a collaborative transitional care program implemented by a 7-hospital health care system and a postacute senior care service provider organization to pilot a transitional care program (Transitions Across Care Settings [TRACS]) for improving coordination of care for their mutual patients and (2) share results and lessons learned from this quality initiative.The goal of the TRACS program, which used the Coleman Care Transitions Intervention model, was to reduce 30-day readmissions to lower than the national averages for an initial target population of inpatients with pneumonia, congestive heart failure, and acute myocardial infarction diagnoses.The overall readmission rate for 104 patients in the pilot TRACS program was 4.8%. Readmission rates were 0% for acute myocardial infarction, 7.1% for congestive heart failure, and 4.4% for pneumonia.A culture of patient safety was facilitated by a registered nurse transitions coach through consistent communication and flow of patient information during patient hand offs across the care continuum. More than 1000 patients are already admitted to the next iteration of the TRACS program, resulting in a sustainable enterprise.

For land management agencies such as Parks Canada that are tasked with maintaining the ecological integrity of protected, natural landscapes, dealing with the impacts of non-indigenous species on forest succession is a serious management concern. In both Terra Nova and Gros Morne National Parks (island of Newfoundland, Canada), the cumulative impacts of non-native species are negatively affecting the capacity of a dominant conifer, balsam fir (Abies balsamea), to regenerate following canopy disturbance by forest insects. Early development of an understory fir layer is compromised by heavy predation on female cones by red squirrels (Tamiasciurus hudsonicus), and post-dispersal seed and seedling predation by non-native rodents and slugs. Taller saplings are then subjected to heavy browsing from non-native moose (Alces alces) so that recruitment to reproductive-aged trees is largely inhibited. An indirect effect of the long-term removal of understory fir is that seedbeds are shifting from optimal f...

Theories of density-dependent habitat selection predict that competitive interference should produce curvilinear relationships when the population densities in adjacent habitats are graphed against each other. We tested the theory by manipulating population densities of brook trout (Salvelinus fontinalis) in four separate natural-stream enclosures containing flat and riffle habitats. Brook trout distributions in streams typically reflect a size-based dominance hierarchy. As predicted by theory, interference among individuals was revealed by curved regressions of density in the paired habitats (isodars). Brook trout exhibited no strong preference for either habitat at low population densities. Habitat preferences emerged clearly at higher densities, apparently reflecting the distribution of suitable sites in the habitat pairs. Predicted bodysize distributions between flat and riffle were mirrored consistently by those observed in the population. The isodar analysis, based only on density data, revealed the...

The successful integration of theories of habitat selection into landscape ecology depends upon the proper identification of habitat. Habitats must be distinguished at appropriate spatial scales, and evidence must be provided that individuals recognize and respond to the habitat classification. We use evolutionary theories to document how density- dependent habitat selection and habitat variation can be applied to identify habitats in landscapes. We apply our protocol to small-mammal (Clethrionomys gapperi) populations across a series of repeated landscapes in the Hudson Bay Lowland of Ontario, Canada. We postulated initially that the landscapes were composed of two easily distinguishable habitats, but our protocol demonstrated three habitat types influencing density-dependent habitat selection by C. gapperi. The third habitat has profound implications for population regu- lation in the lowland and highlights the importance of proper habitat identification.

Nonrandom assemblies of small mammals conform, on average, to a simple pattern discovered by Barry Fox: "Species entering a community will tend to be drawn from a different group until each group is represented, and then the rule repeats." We demonstrate that the Fox assembly pattern is a probabilistic consequence of adding guild structure to models of consumer-resource competition. Assemblies agreeing with the Fox pattern will occur more frequently than those that do not agree with it. High-probability states of coexistence occurring in heterogeneous habitats will frequently include lower-probability states in habitat subsamples. In communities composed of many guilds, low-probability "non-Fox" states representing i guilds should occupy a broader range of habitat variation than should subsets of high-probability Fox states representing fewer guilds. Differences in resource gradients among habitats should produce a correlated habitat bias in guild representation. Patterns of community assembly from divers...

We estimated local and metapopulation effective sizes ([Formula: see text] and meta-[Formula: see text]) for three coexisting salmonid species (Salmo salar, Salvelinus fontinalis, Salvelinus alpinus) inhabiting a freshwater system comprising seven interconnected lakes. First, we hypothesized that [Formula: see text] might be inversely related to within-species population divergence as reported in an earlier study (i.e., FST: S. salarS. fontinalisS. alpinus). Using the approximate Bayesian computation method implemented in ONeSAMP, we found significant differences in [Formula: see text] ([Formula: see text]) between species, consistent with a hierarchy of adult population sizes ([Formula: see text]). Using another method based on a measure of linkage disequilibrium (LDNE: [Formula: see text]), we found more finite [Formula: see text] values for S. salar than for the other two salmonids, in line with the results above that indicate that S. salar exhibits the lowest [Formula: see text] among the three species. Considering subpopulations as open to migration (i.e., removing putative immigrants) led to only marginal and non-significant changes in [Formula: see text], suggesting that migration may be at equilibrium between genetically similar sources. Second, we hypothesized that meta-[Formula: see text] might be significantly smaller than the sum of local [Formula: see text]s (null model) if gene flow is asymmetric, varies among subpopulations, and is driven by common landscape features such as waterfalls. One 'bottom-up' or numerical approach that explicitly incorporates variable and asymmetric migration rates showed this very pattern, while a number of analytical models provided meta-[Formula: see text] estimates that were not significantly different from the null model or from each other. Our study of three species inhabiting a shared environment highlights the importance and utility of differentiating species-specific and landscape effects, not only on dispersal but also in the demography of wild populations as assessed through local [Formula: see text]s and meta-[Formula: see text]s and their relevance in ecology, evolution and conservation.

Landscape genetics holds promise for the forecasting of spatial patterns of genetic diversity based on key environmental features. Yet, the degree to which inferences based on single species can be extended to whole communities is not fully understood. We used a pristine and spatially structured community of three landlocked salmonids (Salvelinus fontinalis, Salmo salar, and Salvelinus alpinus) from Gros Morne National Park (Newfoundland, Canada) to test several predictions on the interacting effects of landscape and life history variation on genetic diversity, neutral divergence, and gene flow (m, migration rate). Landscape factors consistently influenced multispecies genetic patterns: (i) waterfalls created strong dichotomies in genetic diversity and divergence between populations above and below them in all three salmonids; (ii) contemporary m decreased with waterway distance in all three species, while neutral genetic divergence (h) increased with waterway distance, albeit in only two taxa; (iii) river flow generally produced downstream-biased m between populations when waterfalls separated these, but not otherwise. In contrast, we expected differential life history to result in a hierarchy of neutral divergence (S. salar > S. fontinalis > S. alpinus) based on disparities in dispersal abilities and population size from previous mark-recapture studies. Such hierarchy additionally matched varying degrees of spatial genetic structure among species revealed through individual-based analyses. We conclude that, whereas key landscape attributes hold power to predict multispecies genetic patterns in equivalent communities, they are likely to interact with species-specific life history attributes such as dispersal, demography, and ecology, which will in turn affect holistic conservation strategies.

Interpreting patterns of population structure in nature is often challenging, especially in dynamic landscapes where population genetic connectivity evolves over time. In this study, we document the absence of migration-drift equilibrium in a stream-dwelling euryhaline fish resulting from past fine-scale drainage rearrangements and evaluate the relative contribution of past and current hydrological landscapes on observed population structure. Based on allelic variation at nine microsatellite loci, genetic relationships among 12 populations of brook charr, Salvelinus fontinalis, from Gros Morne National Park of Canada (GMNP, Newfoundland, Canada) did not reflect current stream hierarchical structure. In addition, we observed no correlation between population differentiation and contemporary landscape features (waterway distance and sums of altitudinal differences). Instead, population relationships were consistent with historical hydrological structure predicted a priori based on geomorphological and biogeographical evidences. Also, population differentiation was strongly correlated with inferred historical landscape features. Contemporary barriers have apparently preserved the signature of past genetic connectivity by constraining gene flow. Based on the relationships between population differentiation and current and past landscape features at various spatial scales, we suggest that brook charr genetic diversity in GMNP is mostly the result of small distance migrations at the time of colonization and subsequent differentiation through drift. This study highlights the potential of approaching landscapes from a combination of contemporary and historical perspectives when interpreting nonequilibrium population structures resulting from landscape rearrangement.

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