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Human‐mediated transport of species outside their natural range is a rapidly growing threat to biodiversity, particularly for island ecosystems that have evolved in isolation. The genetic structure underpinning island populations will largely determine their response to increased transport and thus help to inform biosecurity management. However, this information is severely lacking for some groups, such as the soil fauna. We therefore analysed the phylogeographic structure of an indigenous and an invasive springtail species (Collembola: Poduromorpha), each distributed across multiple remote sub‐Antarctic islands, where human activity is currently intensifying. For both species, we generated a genome‐wide SNP data set and additionally analysed all available COI barcodes. Genetic differentiation in the indigenous springtail Tullbergia bisetosa is substantial among (and, to a lesser degree, within) islands, reflecting low dispersal and historic population fragmentation, while COI patterns reveal ancestral signatures of postglacial recolonization. This pronounced geographic structure demonstrates the key role of allopatric divergence in shaping the region's diversity and highlights the vulnerability of indigenous populations to genetic homogenization via human transport. For the invasive species Hypogastrura viatica, nuclear genetic structure is much less apparent, particularly for islands linked by regular shipping, while diverged COI haplotypes indicate multiple independent introductions to each island. Thus, human transport has likely facilitated this species' persistence since its initial colonization, through the ongoing introduction and inter‐island spread of genetic variation. These findings highlight the different evolutionary consequences of human transport for indigenous and invasive soil species. Crucially, both outcomes demonstrate the need for improved intraregional biosecurity among remote island systems, where the policy focus to date has been on external introductions. [ABSTRACT FROM AUTHOR]

Large herbivores and carnivores today often only occupy small fractions of their former ranges, and restoring them is a conservation priority. Reintroductions may serve two critical goals in this context: (1) to expand and connect existing populations, or (2) to increase the number of separate populations as insurance in case individual populations are lost, for example, to disease. We developed an approach to identify reintroduction sites for both purposes, using an applied example of European bison or wisent (Bison bonasus) in Poland. Using a large occurrence dataset from all extant herds in Poland, we mapped suitable wisent habitats throughout Poland using a species distribution modelling approach. We identified 47 patches of suitable habitat, together covering 20,710 km2, and used graph theory tools to identify the top candidate reintroduction sites for (1) connecting existing herds into larger metapopulations or (2) establishing 'reservoir' herds that could serve as a backup in case of mass die‐offs. The most well‐connected habitat patches ranged between 203 and 728 km2 and occurred mainly in north‐western and south‐eastern Poland, in close vicinity to other free‐ranging herds. In contrast, candidate sites for reservoir herds were smaller (204–410 km2) and occurred mainly in central Poland. Our approach provides a possible blueprint for wisent reintroductions in Poland. More broadly, our work also highlights how jointly planning for multiple conservation goals for wide‐ranging species that depend on reintroductions or translocations can be achieved at the regional scale. [ABSTRACT FROM AUTHOR]

Understanding large‐scale migratory behaviours, local movement patterns and population connectivity are critical to determining the natural processes and anthropogenic stressors that influence population dynamics and for developing effective conservation plans. Atlantic tarpon occur over a broad geographic range in the Atlantic Ocean where they support valuable subsistence, commercial and recreational fisheries. From 2001 through 2018, we deployed 292 satellite telemetry tags on Atlantic tarpon in coastal waters off three continents to document: (a) seasonal migrations and regional population connectivity; (b) freshwater and estuarine habitat utilization; (c) spawning locations; and (d) shark predation across the south‐eastern United States, Gulf of Mexico and northern Caribbean Sea. These results showed that some mature tarpon make long seasonal migrations over thousands of kilometres crossing state and national jurisdictional borders. Others showed more local movements and habitat use. The tag data also revealed potential spawning locations consistent with those inferred in other studies from observations of early life stage tarpon leptocephalus larvae. Our analyses indicated that shark predation mortality on released tarpon is higher than previously estimated, especially at ocean passes, river mouths and inlets to bays. To date, there has been no formal stock assessment of Atlantic tarpon, and regional fishery management plans do not exist. Our findings will provide critical input to these important efforts and assist the multinational community in the development of a stock‐wide management information system to support informed decision‐making for sustaining Atlantic tarpon fisheries. [ABSTRACT FROM AUTHOR]

Research on the genetics of invasive species often focuses on patterns of genetic diversity and population structure within the introduced range. However, a growing body of literature is demonstrating the need to study how native genotypes affect both ecological and evolutionary mechanisms within the introduced range. Here, we used genotyping‐by‐sequencing to study both native and introduced ranges of the amphiatlantic marine invertebrate Ciona intestinalis. A previous study using microsatellites analysed samples collected along the Swedish west coast and showed the presence of genetically distinct lineages in deep and shallow waters. Using 1,653 single nucleotide polymorphisms (SNPs) from newly collected samples (285 individuals), we first confirmed the presence of this depth‐defined genomic divergence along the Swedish coast. We then used approximate Bayesian computation to infer the historical relationship among sites from the North Sea, the English Channel and the northwest Atlantic and found evidence of ancestral divergence between individuals from deep waters off Sweden and individuals from the English Channel. This divergence was followed by a secondary contact that led to a genetic admixture between the ancestral populations (i.e., deep Sweden and English Channel), which originated the genotypes found in shallow Sweden. We then revealed that the colonization of C. intestinalis in the northwest Atlantic was as a result of an admixture between shallow Sweden and the English Channel genotypes across the introduced range. Our results showed the presence of both past and recent genetic admixture events that together may have promoted the successful colonizations of C. intestinalis. Our study suggests that secondary contacts potentially reshape the evolutionary trajectories of invasive species through the promotion of intraspecific hybridization and by altering both colonization patterns and their ecological effects in the introduced range. [ABSTRACT FROM AUTHOR]

A set of seven microsatellite genetic markers were used to examine the population connectivity of the red urchin, Strongylocentrotus franciscanus. I compared four locations in California and two locations in British Columbia (data previously published by Miller et al. 2004). I found significant genetic differentiation between the British Columbia and the California populations, however among the California populations there were few indications of differentiation. I detected some differentiation between recruits and adults within one California population. These results show for the first time that, on a range wide scale, populations of red urchins are genetically divergent. However, on a regional scale, which may be more relevant to fisheries and marine reserve management, there does not seem to be strong genetic differentiation. These findings do not exclude the possibility that there may be substantial local recruitment within populations.

The California Current Ecosystem (CCE) is a dynamic marine ecosystem from which many socioeconomically important fisheries species are harvested. Here, a genotyping-by-sequencing (GBS) approach was used to examine genomic variation in an early life stage (megalopae) of the Dungeness crab (Cancer magister), which constitutes the most valuable single-species commercial fishery in the CCE. Variation in abundance and timing of megalopae recruitment has been extensively studied for over two decades in Coos Bay, Oregon, United States. Within the CCE, documented timing of Dungeness crab life history events indicates that coastal megalopae recruitment is expected to occur April through July; however, long-term studies in Coos Bay have observed late-season recruitment from August to October. Based on variation at 1,913 presumably neutral loci, evidence was found for weak, yet significant differentiation (FST estimate = 0.0011) between the 2014 expected-season recruits (n = 47) and late-season recruits (n = 47) collected in Coos Bay. However, two putatively adaptive loci with a high FST estimate (0.2036) between expected-season and late-season recruits were identified. These findings support the hypothesis that expected-season and late-season megalopae recruiting to Coos Bay within the same year may have originated from different locations or from different breeding groups. Understanding marine species connectivity between ecosystems is important when considering how future changes in ocean conditions may impact fishery harvests.

Aim: Rapid anthropogenic warming coupled with changes in land use is altering the distributions of species, with consequences for ecosystem functioning and services. It is crucial to evaluate species range shifts based on understanding of the interaction of temperature with non‐climatic factors such as habitat availability and dispersal potential. Here, we aim to investigate roles of environmental temperature, habitat availability and population connectivity on the distributions of hard‐shore intertidal animals. We further examine potential roles of extensive artificial seawall construction in enabling poleward expansion of species in China, thus reshaping coastal biogeography. Location: Chinese coast. Time period: 2013–2017. Major taxa studied: Intertidal invertebrates. Methods: We took an integrative approach encompassing distributional ecology, thermal physiology, molecular genetics, heat budget modelling and larval dispersal to elucidate how interacting multiple drivers, including temperature, habitat availability and larval dispersal, determine distributions of hard‐shore invertebrates, focusing on what sets their range edges at a boundary between biogeographic provinces. Results: Our results untangle the complex interactions of global climate change with the impacts of regional scale coastal development. Temperature, larval transport and habitat availability are the major proximate factors controlling the range limits of coastal marine species. The artificial shorelines provide suitable habitats for hard‐shore species on the Yangtze River Delta, and minimum temperature in winter is an important factor setting the new northern range limit of these hard‐shore species along the Chinese coast. Main conclusions: In the face of global warming and global sprawl of marine hard infrastructure, species distributions, community structures and biogeographic patterns are experiencing dramatic changes. The combined influence of multiple human stressors including climate change and artificial shorelines can be evaluated by using a multidisciplinary framework, including ecological distribution, physiological sensitivity of species to these stressors, and the role of dispersal in maintaining population connectivity. [ABSTRACT FROM AUTHOR]

Gene flow is an important evolutionary force that enables adaptive responses of plant pathogens in response to changes in the environment and plant disease management strategies. In this study, we made a direct inference concerning gene flow in the Irish famine pathogen Phytophthora infestans between two of its hosts (potato and tomato) as well as between China and India. This was done by comparing sequence characteristics of the eukaryotic translation elongation factor 1 alpha (eEF‐1α) gene, generated from 245 P. infestans isolates sampled from two countries and hosts. Consistent with previous results, we found that eEF‐1α gene was highly conserved and point mutation was the only mechanism generating any sequence variation. Higher genetic variation was found in the eEF‐1α sequences in the P. infestans populations sampled from tomato compared to those sampled from potato. We also found the P. infestans population from India displayed a higher genetic variation in the eEF‐1α sequences compared to China. No gene flow was detected between the pathogen populations from the two countries, which is possibly attributed to the geographic barrier caused by Himalaya Plateau and the minimum cross‐border trade of potato and tomato products. The implications of these results for a sustainable management of late blight diseases are discussed. [ABSTRACT FROM AUTHOR]

Managing agricultural pests that use multiple host plant species is a challenge when individuals move between host plants in natural vegetation and agricultural environments. The green mirid (Creontiades dilutus) Stål (Hemiptera: Miridae) is endemic to Australia and routinely invades cotton from local uncultivated vegetation, but may also originate from remote locations in the arid continental interior. This bug is polyphagous and highly mobile, which contributes to its pest status in cotton L. (Malvaceae) systems as well as its persistence in arid environments with sparsely distributed ephemeral host plants. The aim of this study was to evaluate how C. dilutus individuals use a variety of host species across remote arid regions and highly managed agricultural landscapes. Structured field surveys spanning vast areas across the Simpson Desert in the arid heart of Australia, as well as subcoastal cotton production systems, were designed to evaluate host use across environments that share few plant species. High numbers of C. dilutus were collected from Cullen australasicum (Schltdl.) J.W.Grimes (Fabaceae) (perennial hosts) and Goodenia cycloptera R.Br. (Goodeniaceae) (ephemeral hosts) in the desert following rain. In agricultural environments, C. dilutus bugs were mostly found on irrigated Medicago sativa L. (Fabaceae) (lucerne), and to a lesser extent Melilotus indicus (L.) All. (Fabaceae) near rivers. Significantly, bugs were on these plants prior to the planting of cotton across all environments surveyed. These data allow inferences relating host use, host abundance, and insect migration to one another to understand the connection that C. dilutus bugs have between arid and agricultural environments. [ABSTRACT FROM AUTHOR]

The variation in shelled marine gastropod morphology across small spatial scales can reflect restricted population connectivity, resulting in evolution or plastic responses to environmental heterogeneity. The common whelk, Buccinum undatum , is a subtidal gastropod, ubiquitous in the North Atlantic, that exhibits considerable spatial variation in shell morphology and colour. Given that species delimitation in shelled marine gastropods is often based on shell characteristics, such morphological variation can lead to taxonomic confusion. Phylogeographical analysis based on mitochondrial DNA and microsatellites suggested cryptic species composed of Western and Eastern North Atlantic common whelk populations, the separation of which dates to the onset of the Pleistocene glaciation ~2.1 Mya. Divergence within the Eastern North Atlantic is more recent and characterized by isolation by distance. In the present study, phenotypic variation in shell morphology across the North Atlantic range is analysed and compared with molecular divergence. The morphological variation of B. undatum populations reflected the pattern observed for the molecular markers only for certain comparisons of populations and might, in other cases, reflect larger constraints on the morphological variation and, possibly, the impact of environmental influences. [ABSTRACT FROM AUTHOR]

The purpose of this study was to revisit the mitochondrial genetic divergence of North Atlantic populations of the subtidal gastropod Buccinum undatum , because previous mitochondrial DNA (mtDNA) analysis by Pálsson et al. (2014) included 16S ribosomal RNA sequences that were incorrectly assigned to the species. In the present study, population mtDNA variation is now assessed using COI sequences obtained from previous research (Pálsson et al. , 2014) and, to increase the geographical cover of the study, data from recently assembled transcriptomes of 96 Icelandic whelks (Jónsson et al. , 2019) and GenBank are also used. To estimate the mtDNA divergence in B. undatum across the North Atlantic, two species screening indices were used: automatic barcode gap discovey (ABGD; Puillandre et al. , 2012a) and species screening threshold index (SSTI; Witt et al. , 2006). Phylogenetic reconstruction revealed monophyletic Eastern and Western North Atlantic whelk lineages, which diverged early in the Pleistocene glaciation (2.1 Mya), followed by a subsequent divergence event between Greenlandic and Canadian populations at 1.3 Mya. Species screening indices, ABGD and SSTI, indicated cryptic speciation or allopatric divergence. Genetic distances between populations from the two continents were similar to or greater than interspecific genetic distances across several North Pacific and North Atlantic Buccinum species. [ABSTRACT FROM AUTHOR]

• Ottelia acuminata var. jingxiensis is confined to several Karst rivers. • Genetic connectivity and genetic variation were assessed based on 11 microsatellites. • Both water flow and zoochory (or mankind) were major contributors for gene exchange. • Recent habitat fragmentation resulted in decreased gene flow. • Separate conservation among rivers and watercourse dredging were suggested. Dispersal is a key evolutionary force affecting gene flow and genetic diversity. Therefore, analysis of population connectivity plays an important role in protecting endangered species. Ottelia acuminata var. jingxiensis is a perennial endangered aquatic plant, and present in several karst rivers of Yunnan–Guizhou Plateau. We estimated the genetic variation and population connectivity by nuclear microsatellites in 11 populations mainly from three rivers. The plant showed low genetic diversity (H E = 0.205–0.367), which was mainly explained by its critically restricted geographical range. Meanwhile, relatively low genetic differentiation (F ST = 0.186; G" ST = 0.242) was found compared with that of other studies about varieties of O. acuminata in isolated habitats. Cluster analyses based on different approaches consistently showed populations from the same river clustered together, suggesting water flow acting as corridors for dispersal; additionally, bidirectional gene flows within and among rivers indicated that zoochory or mankind were also major contributors to gene exchange. The results showed that contemporary gene flow was much lower than historical gene flow, suggesting that recent habitat fragmentation resulted in decreased gene flow. We recommend watercourse dredging within rivers to enhance habitat stability and to improve connectivity among populations. In addition, the different populations from different rivers or isolated habitats should be protected to maintain the genetic diversity. [ABSTRACT FROM AUTHOR]

The transition from the Middle Paleolithic (MP) to the Upper Paleolithic (UP), circa 40kya, is viewed as a major turning point in human evolution, in terms of the material culture, demography, and geographical expansion of modern humans. However, attempts to identify an origin of this so-called 'revolution' in the form of a particular stone-tool techno-complex, representing cultural modernity, which spread across the human range, have failed. Instead, the archaeological record of this period comprises multiple 'transitional techno-complexes', some associated with modern humans and others with Neanderthals. The cultures that these techno-complexes represent are characterized by precursors of the material cultures of the UP, often alongside features that suggest local cultural continuity. The broadly simultaneous appearance of these transitional cultures, despite a lack of a clear common origin, is puzzling. We suggest that these local 'revolutions' had a common underlying driver, which explains the simultaneous appearance of transitional techno-complexes, but that this driver did not determine the particular form of each local revolution. We propose that the driver of the transition to the UP was an increase in inter-population connectivity, both within- and between-species, which allowed local cultures to rapidly evolve and to attain greater complexity than ever before. We suggest that this change was driven by the interaction between modern humans and Neanderthals. In this article we outline processes that are likely to have influenced inter-population connectivity, bringing together evolutionary and ecological perspectives alongside insights from the field of cultural evolution. • The transition from the middle to upper Paleolithic is characterized by multiple transitional techno-complexes. • Many transitional techno-complexes seem independent of one another, and display local geographic continuity. • The coordinated appearance 50-40kya of independent transitional techno-complexes is puzzling, and suggests a common driver. • We suggest the driver was inter-population connectivity increase among moderns and Neanderthals, within and between species. • We propose dynamics in demography, natural selection, and cultural evolution that could have increased connectivity. [ABSTRACT FROM AUTHOR]

The common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the world's tropical and subtropical oceans in waters greater than 20°C. Life-history variables, migratory behaviour, and genetic markers have been used to define major stocks in the central Atlantic Ocean and Mediterranean Sea. Here, we used the mitochondrial DNA gene NADH subunit 1 (688 bp) to test for differences between population groups. A total of 103 haplotypes were detected among 203 fish. Gene diversities in samples were large and similar among populations (mean h  = 0.932; range 0.894–0.987), but nucleotide diversities varied widely among samples (range π  = 0.004–0.034) and appear to reflect population histories. Principal component analysis revealed two large populations groups, and the analysis of molecular variation and pairwise values of ΦST resolved population structure within these groups. Populations in the eastern Atlantic and Mediterranean showed the largest amounts of divergence from one another (ΦCT = 0.331). Adult movement and biophysical barriers to larval dispersal may explain contemporary differences between stocks, but the divergent populations in the Mediterranean Sea are likely due to isolations by cold temperature barriers during Pleistocene glaciations. The geographically large stock groupings require international cooperation in the harvest management and conservation of local dolphinfish populations. [ABSTRACT FROM AUTHOR]

Symbiotic relationships are a common phenomenon among marine invertebrates, forming both obligatory and facultative dependencies with their host. Here, we investigate and compare the population structure of two crustacean species associated with both shallow and mesophotic ecosystems: an obligate symbiont barnacle (Ceratoconcha domingensis) , of the coral Agaricia lamarcki and a meiobenthic, free-living harpacticoid copepod (Laophontella armata). Molecular analyses of the Cytochrome Oxidase Subunit I (COI) gene revealed no population structure between mesophotic and shallow barnacle populations within south-west Puerto Rico (ΦST = 0.0079, P = 0.33). The absence of population structure was expected due to the pelagic naupliar larvae of the barnacles and the connectivity patterns exhibited by the coral itself within the same region. Laophontella armata exhibited significant structure based on the mitochondrial COI gene between the mesophotic reef ecosystem of El Seco, Puerto Rico and mangrove sediments of Curaçao (ΦST = 0.2804, P = 0.0). The El Seco and Curaçao copepods shared three COI haplotypes despite the obligatory benthic development of harpacticoid copepods and the geographic distance between the two locations. Three other COI haplotypes from El Seco exhibited higher than expected (up to 7%) intra-species variability, potentially representing three new cryptic species of harpacticoid copepods or rare, deeply divergent lineages of L. armata. This result is evidence for the urgent need of a deeper investigation into the meiofauna diversity associated with mesophotic coral ecosystems (MCEs) , arguably the most diverse metazoan component of MCEs. [ABSTRACT FROM AUTHOR]

Disentangling pathways by which nonindigenous species expand and spread regionally remains challenging. Molecular ecology tools are often employed to determine the origins and spread of introduced species, but the complexities of some organisms may be reducing the efficacy of these tools. Some colonial species exhibit complexities by way of chimerism and winter colony regression, which may alter the genetic diversity of populations and mask the connectivity occurring among them. This study uses nuclear microsatellite data and simple GIS‐based modeling to investigate the influence of chimerism and winter regression on the genetic diversity and patterns of genetic population connectivity among colonies of Didemnum vexillum on artificial substrates. Colonies sampled in summer were shown to form a metapopulation, with high levels of admixture, extreme outcrossing, and some substructure. These patterns were consistent within the subsampled winter colonies and with the inclusion of chimeric data. However, allelic richness and diversity were significantly different between winter and summer samples, altering interpretations relating to population connectivity and pelagic larval duration. This study demonstrates the importance of including seasonal sampling and imperative life history traits in genetic studies for clear interpretations and the successful management of introduced species. [ABSTRACT FROM AUTHOR]

Understanding the causes of larval dispersal is a major goal of marine ecology, yet most research focuses on proximate causes. Here we ask how ultimate, evolutionary causes affect dispersal. Building on Hamilton and May's classic 1977 article "Dispersal in Stable Habitats," we develop analytic and simulation models for the evolution of dispersal kernels in spatially structured habitats. First, we investigate dispersal in a world without edges and find that most offspring disperse as far as possible, opposite the pattern of empirical data. Adding edges to our model world leads to nearly all offspring dispersing short distances, again a mismatch with empirical data. Adding resource heterogeneity improves our results: most offspring disperse short distances with some dispersing longer distances. Finally, we simulate dispersal evolution in a real seascape in Belize and find that the simulated dispersal kernel and an empirical dispersal kernel from that seascape both have the same shape, with a high level of short-distance dispersal and a low level of long-distance dispersal. The novel contributions of this work are to provide a spatially explicit analytic extension of Hamilton and May's 1977 work, to demonstrate that our spatially explicit simulations and analytic models provide equivalent results, and to use simulation approaches to investigate the evolution of dispersal kernel shape in spatially complex habitats. Our model could be modified in various ways to investigate dispersal evolution in other species and seascapes, providing new insights into patterns of marine larval dispersal. [ABSTRACT FROM AUTHOR]

Diaporthe eres is considered one of the most important causal agents of many plant diseases, with a broad host range worldwide. In this study, multiple sequences of ribosomal internal transcribed spacer region (ITS), translation elongation factor 1-α gene (EF1-α), beta-tubulin gene (TUB2), calmodulin gene (CAL), and histone-3 gene (HIS) were used for multi-locus phylogenetic analysis. For phylogenetic analysis, maximum likelihood (ML), maximum parsimony (MP), and Bayesian inferred (BI) approaches were performed to investigate relationships of D. eres with closely related species. The results strongly support that the D. eres species falls into a monophyletic lineage, with the characteristics of a species complex. Phylogenetic informativeness (PI) analysis showed that clear boundaries could be proposed by using EF1-α, whereas ITS showed an ineffective reconstruction and, thus, was unsuitable for speciating boundaries for Diaporthe species. A combined dataset of EF1-α, CAL, TUB2, and HIS showed strong resolution for Diaporthe species, providing insights for the D. eres complex. Accordingly, besides D. biguttusis, D. camptothecicola, D. castaneae-mollissimae, D. cotoneastri, D. ellipicola, D. longicicola, D. mahothocarpus, D. momicola, D. nobilis, and Phomopsis fukushii, which have already been previously considered the synonymous species of D. eres, another three species, D. henanensis, D. lonicerae and D. rosicola, were further revealed to be synonyms of D. eres in this study. In order to demonstrate the genetic diversity of D. eres species in China, 138 D. eres isolates were randomly selected from previous studies in 16 provinces. These isolates were obtained from different major plant species from 2006 to 2020. The genetic distance was estimated with phylogenetic analysis and haplotype networks, and it was revealed that two major haplotypes existed in the Chinese populations of D. eres. The haplotype networks were widely dispersed and not uniquely correlated to specific populations. Overall, our analyses evaluated the phylogenetic identification for D. eres species and demonstrated the population diversity of D. eres in China.

Knowledge about connectivity between populations is essential for the fisheries management of commercial species. The lobster Jasus frontalis inhabits two oceanic island groups, the Juan Fernández Archipelago and the Desventuradas Islands, separated by 800 km. Since this species is primarily exploited in the Juan Fernández Archipelago, knowledge of the connectivity patterns among islands is foundational for species management. Here, we used variability at single-nucleotide polymorphisms (SNPs) and individual-based modeling (IBM) to estimate the genetic structure and connectivity between J. frontalis populations in these island groups. The variability at 9090 SNPs suggests two genetic populations, one in the Juan Fernández Archipelago and one in the Desventuradas Islands. Furthermore, IBM suggests an asymmetric connectivity pattern, with particles moving from the Juan Fernández Archipelago to the Desventuradas Islands but not vice versa. Since the IBM analysis suggests asymmetric larval movement between the islands, and the genetic analysis indicates isolation between the Juan Fernández Archipelago and the Desventuradas Islands, larval retention mechanisms such as small-scale oceanographic processes or behavior could hinder larval movement between islands. This study highlights the importance of using more than one methodology to estimate population connectivity. • Population genetics and connectivity in the spiny lobster Jasus frontalis were studied through genetic and modeling analyses. • Variability at 9090 SNPs suggests two genetic populations separated by 850 km. • Modeling analysis showed a northward asymmetric pattern of connectivity. • The analyses suggest an effect of larval behavior that would avoid larval movement between the studies islands. [ABSTRACT FROM AUTHOR]

Effective management of blacktip sharks relies on a comprehensive understanding of population distribution and stock structure. Previous stock separations and the implementation of regional quotas have proven successful in maintaining the sustainable harvest of blacktip sharks in both the Western North Atlantic and United States Gulf of Mexico (US GoM), in commercial and recreational fisheries. Within the US GoM, finer scale biological separation between blacktips in western and eastern regions has been supported through tagging, genetic, and diet data. This study provides additional evidence of unique ecological isotopic niche areas and δ15N and δ13C values for blacktip sharks from the western, central, and eastern US GoM across muscle and vertebral tissues that reflect different isotope turnover rates. Blacktip sharks from western and central regions exhibited isotope values and niches that were significantly smaller compared to eastern sharks, with enriched δ13C and depleted δ15N west of 88ºN. Ontogenetic shifts were noted for most regions and there was no crossover or overlap in average isotope values from early to recent life between regions. These spatiotemporal patterns suggest that in the year following birth and prior to the time of capture, blacktip sharks on the central and western shelves have separated ecologically from blacktips on the eastern US GoM Florida shelf. • δ15N and δ13C values in blacktip shark vertebrae and muscle tissue vary by region. • Isotopic niches exhibited minimal overlap between the eastern and western GoM. • Lifetime regional residency suggested across ontogeny in vertebrae. • Combined isotopic tracers support ecological separation of GoM blacktips sharks. [ABSTRACT FROM AUTHOR]

This “Perspectives” paper identifies aspects of tiger shark (Galeocerdo cuvier) biology that are currently unknown or for which additional data are needed to improve interpretive power. Some of these data gaps may be regional. Technical or methodological approaches to acquiring these data are suggested. Some of these technologies already exist, some are in development and some exist in concept only. Reproductive biology and behavior, social interactions and the behavioral ecology of sub-adults are among the areas identified as deserving of future research effort.

Planktonic larvae are thought to be very susceptible to offshore advection in upwelling regimes, increasing dispersal and decreasing recruitment. However, larvae of 42 species of nearshore benthic crustaceans primarily developed on the inner shelf at locations both in (98.5%) and away (99.8%) from a perennial upwelling center in the upwelling season of a recruitment-limited region characterized by persistent, strong, upwelling. During three cross-shelf cruises conducted at each location, larvae of 21 species remained on the inner shelf at both sites by occurring beneath seaward-flowing surface currents while larvae of other species migrated to midshelf (four species) or offshore (14 species) by initially developing near the surface. Postlarvae apparently returned to shore either deep in landward-flowing upwelled water or near the surface where behavior allows them to be transported shoreward by internal waves, diel wind cycles or wind relaxation events. Thus, recruitment limitation in upwelling regimes does not appear to be caused by larval mortality from offshore transport, requiring new research directions to advance our understanding of population dynamics, structure and connectivity.

The giant panda is an example of a species that has faced extensive historical habitat fragmentation, and anthropogenic disturbance and is assumed to be isolated in numerous subpopulations with limited gene flow between them. To investigate the population size, health, and connectivity of pandas in a key habitat area, we noninvasively collected a total of 539 fresh wild giant panda fecal samples for DNA extraction within Wolong Nature Reserve, Sichuan, China. Seven validated tetra‐microsatellite markers were used to analyze each sample, and a total of 142 unique genotypes were identified. Nonspatial and spatial capture–recapture models estimated the population size of the reserve at 164 and 137 individuals (95% confidence intervals 153–175 and 115–163), respectively. Relatively high levels of genetic variation and low levels of inbreeding were estimated, indicating adequate genetic diversity. Surprisingly, no significant genetic boundaries were found within the population despite the national road G350 that bisects the reserve, which is also bordered with patches of development and agricultural land. We attribute this to high rates of migration, with four giant panda road‐crossing events confirmed within a year based on repeated captures of individuals. This likely means that giant panda populations within mountain ranges are better connected than previously thought. Increased development and tourism traffic in the area and throughout the current panda distribution pose a threat of increasing population isolation, however. Maintaining and restoring adequate habitat corridors for dispersal is thus a vital step for preserving the levels of gene flow seen in our analysis and the continued conservation of the giant panda meta‐population in both Wolong and throughout their current range. We employed noninvasive molecular genetic methods in Wolong Nature Reserve to investigate the giant panda populations in the Northern Qionglai Mountains, with a particular focus on connectivity. Surprisingly, we found that a major road and historical human settlement and agriculture in the valley have not resulted in genetic differentiation between populations on either side of the disturbance. The high levels of migration and gene flow across areas of anthropogenic disturbance found in our study suggest that giant panda populations likely do not face the levels of population isolation within mountain ranges that have been widely assumed. [ABSTRACT FROM AUTHOR]

Effective management and conservation of migratory bird populations require knowledge and incorporation of their movement patterns and space use throughout the annual cycle. To investigate the little‐known migratory patterns of two grassland bird species, we deployed 180 light‐level geolocators on Grasshopper Sparrows (Ammodramus savannarum) and 29 Argos‐GPS tags on Eastern Meadowlarks (Sturnella magna) at Konza Prairie, Kansas, USA, and six US Department of Defense (DoD) installations distributed across the species' breeding ranges. We analyzed location data from 34 light‐level geolocators and five Argos‐GPS tags attached for 1 year to Grasshopper Sparrows and Eastern Meadowlarks, respectively. Grasshopper Sparrows were present on the breeding grounds from mid‐April through early October, substantially longer than previously estimated, and migrated on average ~2,500 km over ~30 days. Grasshopper Sparrows exhibited strong migratory connectivity only at a continental scale. The North American Great Lakes region likely serves as a migratory divide for Midwest and East Coast Grasshopper Sparrows; Midwest populations (Kansas, Wisconsin, and North Dakota; n = 13) largely wintered in Texas or Mexico, whereas East Coast populations (Maryland and Massachusetts, n = 20) wintered in the northern Caribbean or Florida. Our data from Eastern Meadowlarks provided evidence for a diversity of stationary and short‐ and long‐distance migration strategies. By providing the most extensive examination of the nonbreeding movement ecology for these two North American grassland bird species to date, we refine information gaps and provide key insight for their management and conservation. To investigate the little‐known migratory patterns of two North American grassland bird species, we analyzed location data estimated from 34 light‐level geolocators recovered from Grasshopper Sparrows (Ammodramus savannarum) and five Argos‐GPS tags from Eastern Meadowlarks (Sturnella magna) across much of the two species' breeding ranges. Grasshopper Sparrows exhibited strong migratory connectivity only at a continental scale, while Eastern Meadowlarks provided evidence for a diversity of stationary and short‐ and long‐distance migration strategies. By providing the most extensive examination of the nonbreeding movement ecology for these two North American grassland bird species to date, we refine information gaps and provide key insight for conducting their management and conservation. [ABSTRACT FROM AUTHOR]

Studying population genetics of deep‐sea animals helps us understand their history of habitat colonization and population divergence. Here, we report a population genetic study of the deep‐sea mussel Bathymodiolus platifrons (Bivalvia: Mytilidae) widely distributed in chemosynthesis‐based ecosystems in the Northwest Pacific. Three mitochondrial genes (i.e., atp6, cox1, and nad4) and 6,398 genomewide single nucleotide polymorphisms (SNPs) were obtained from 110 individuals from four hydrothermal vents and two methane seeps. When using the three mitochondrial genes, nearly no genetic differentiation was detected for B. platifrons in the Northwest Pacific. Nevertheless, when using SNP datasets, all individuals in the South China Sea (SCS) and three individuals in Sagami Bay (SB) together formed one genetic cluster that was distinct from the remaining individuals. Such genetic divergence indicated a genetic barrier to gene flow between the SCS and the open Northwest Pacific, resulting in the co‐occurrence of two cryptic semi‐isolated lineages. When using 125 outlier SNPs identified focusing on individuals in the Okinawa Trough (OT) and SB, a minor genetic subdivision was detected between individuals in the southern OT (S‐OT) and those in the middle OT (M‐OT) and SB. This result indicated that, although under the influence of the Kuroshio Current and the North Pacific Intermediate Water, subtle geographic barriers may exist between the S‐OT and the M‐OT. Introgression analyses based on these outlier SNPs revealed that Hatoma Knoll in the S‐OT represents a possible contact zone for individuals in the OT‐SB region. Furthermore, migration dynamic analyses uncovered stronger gene flow from Dai‐yon Yonaguni Knoll in the S‐OT to the other local populations, compared to the reverse directions. Taken together, the present study offered novel perspectives on the genetic connectivity of B. platifrons mussels, revealing the potential interaction of ocean currents and geographic barriers with adaption and reproductive isolation in shaping their migration patterns and genetic differentiation in the Northwest Pacific. [ABSTRACT FROM AUTHOR]

Abstract Larval Atlantic sea scallops (Placopecten magellanicus) simulations in the Middle Atlantic Bight (MAB) from 2006 to 2012 were performed to investigate annual and inter-annual dispersal and connectivity patterns among stock regions. These simulations used a circulation model based on the Regional Ocean Modeling System (ROMS) and an individual-based larval model (IBM) that included larval behavior. The circulation model used realistic dynamical forcing (e.g. , winds, tides, and open ocean boundary conditions), thermo-dynamical fluxes (e.g., solar radiations, sensible and latent heating), and hydrological forcing; the larval IBM included vertical swimming and sinking behaviour, temperature-dependent growth, and settlement. Simulated larvae that reach settlement size and suitable habitat in 45 days are considered 'successful', and two regions are considered 'connected' by larval dispersal when larvae successfully disperse from one region to the other. In general, simulated larval dispersal patterns varied seasonally (28% higher in September and October compared to May and June), among years (2007 through 2009 had 5% lower larval success during August and September compared to other years), and spatially, with larvae released from the northern regions like Long Island acting as a substantive larval source with 14% greater dispersal success and 15% greater connectivity with other regions than those released elsewhere. Over the seven years simulated, the MAB scallop stocks showed high rates of connectivity to regions to the south and more limited and variable connectivity to regions to the north. In species like sea scallops with limited adult mobility, larval dispersal supplies recruits, enables range expansion, and connects populations. Thus, appreciation of dispersal patterns are essential for fishery management of this economically valuable stock. [ABSTRACT FROM AUTHOR]

The Driftless Area of the upper Mississippi River drainage is a unique geographic region because of its complex geological history and the influence of recent, intensive human activities. The longnose dace, Rhinichthys cataractae, is a relatively common, small freshwater fish that is distributed in swift, cool streams within the region. The aim of this study was to determine the spatial genetic differentiation of the longnose dace and define the broad scale environmental variables that shape the distribution of the species in the southwestern portion of the Driftless Area. Genotypic data from seven microsatellite loci were analyzed for 276 individuals from 15 localities representing major drainages within the region in northeast Iowa. Broad scale environmental variables including hydrologic, soil, and climatic factors were evaluated to construct an ecological niche model (ENM) to predict the suitability of habitat for the species within the region. Results of the genetic analyses revealed two distinct, but somewhat admixed genetic clusters of longnose dace in Iowa. The genetic differentiation between localities and between drainages was low to moderate with some evidence of isolation by distance. Most of the variation was observed by differences between individuals within local populations. The ENM generated largely reflected the known distribution of the species in Iowa with a decreasing probability of suitable habitat from northern to southern drainages. Geologic factors played a key role in the model. The distribution and population structure of the longnose dace in the northeast Iowa revealed that isolation by distance, historical processes and the underlying geology are primarily responsible for the observed spatial distribution of genetic variation. [ABSTRACT FROM AUTHOR]

Larval transport by marine organisms is regulated by a combination of vertical swimming behavior and seasonal reproductive timing, but recent studies suggest horizontal swimming behaviors may also be important. Larvae in highly productive coastal upwelling regions are especially vulnerable to offshore transport and must employ effective dispersal “strategies” to return onshore to suitable settlement sites. Using a primitive-equation numerical model, we investigate how horizontal swimming affects nearshore larval supply and potential settlement and connectivity during climatological spring and summer in central California, a region of persistent coastal upwelling within the California Current System. The addition of shoreward swimming with speeds of 1–7 cm s −1 increases nearshore larval supply by a factor of 1.4–13, depending on the speed, timing of its onset, and the vertical swimming behavior of the larvae, which included both diel and ontogenetic vertical migrations. Nearshore larval supply increases approximately linearly with swimming speed integrated over the pelagic larval duration. While pelagic connectivity increases with shoreward swimming for all vertical behaviors investigated, spatial patterns of connectivity, when standardized by nearshore larval supply, are similar with and without horizontal behavior. Onshore swimming broadens the alongshore extent of areas that can act as effective source regions in central California, increasing potential dispersal distances 11–26%. A related statistic, the reverse pelagic connectivity, reveals Monterey Bay and the Gulf of the Farallones as important source regions that should be considered when adaptively managing California's network of marine protected areas. [ABSTRACT FROM AUTHOR]

Abstract: Connectivity among stream fish populations allows for exchange of genetic material and helps maintain genetic diversity, adaptive potential and population stability over time. Changes in species demographics and population connectivity have the potential to permanently alter the genetic patterns of stream fish, although these changes through space and time are variable and understudied in small‐bodied freshwater fish. As a spatially widespread, common species of benthic freshwater fish, the variegate darter (Etheostoma variatum) is a model species for documenting how patterns of genetic structure and diversity respond to increasing isolation due to large dams and how scale of study may shape our understanding of these patterns. We sampled variegate darters from 34 sites across their range in the North American Ohio River basin and examined how patterns of genetic structure and diversity within and between populations responded to historical population changes and dams within and between populations. Spatial scale and configuration of genetic structure varied across the eight identified populations, from tributaries within a watershed, to a single watershed, to multiple watersheds that encompass Ohio River mainstem habitats. This multiwatershed pattern of population structuring suggests genetic dispersal across large distances was and may continue to be common, although some populations remain isolated despite no apparent structural dispersal barriers. Populations with low effective population sizes and evidence of past population bottlenecks showed low allelic richness, but diversity patterns were not related to watershed size, a surrogate for habitat availability. Pairwise genetic differentiation (FST) increased with fluvial distance and was related to both historic and contemporary processes. Genetic diversity changes were influenced by underlying population size and stability, and while instream barriers were not strong determinants of genetic structuring or loss of genetic diversity, they reduce population connectivity and may impact long‐term population persistence. The broad spatial scale of this study demonstrated the large spatial extent of some variegate darter populations and indicated that dispersal is more extensive than expected given the movement patterns typically observed for small‐bodied, benthic fish. Dam impacts depended on underlying population size and stability, with larger populations more resilient to genetic drift and allelic richness loss than smaller populations. Other darters that inhabit large river habitats may show similar patterns in landscape‐scale studies, and large river barriers may impact populations of small‐bodied fish more than previously expected. Estimation of dispersal rates and behaviours is critical to conservation of imperilled riverine species such as darters. [ABSTRACT FROM AUTHOR]

Context: Common species important for ecosystem restoration stand to lose as much genetic diversity from anthropogenic habitat fragmentation and climate change as rare species, but are rarely studied. Salt marshes, valuable ecosystems in widespread decline due to human development, are dominated by the foundational plant species black needlerush (Juncus roemerianus Scheele) in the northeastern Gulf of Mexico.Objectives: We assessed genetic patterns in J. roemerianus by measuring genetic and genotypic diversity, and characterizing population structure. We examined population connectivity by delineating possible dispersal corridors, and identified landscape factors influencing population connectivity.Methods: A panel of 19 microsatellite markers was used to genotype 576 samples from ten sites across the northeastern Gulf of Mexico from the Grand Bay National Estuarine Research Reserve (NERR) to the Apalachicola NERR. Genetic distances (FST and Dch) were used in a least cost transect analysis (LCTA) within a hierarchical model selection framework.Results: Genetic and genotypic diversity results were higher than expected based on life history literature, and samples structured into two large, admixed genetic clusters across the study area, indicating sexual reproduction may not be as rare as predicted in this clonal macrophyte. Digitized coastal transects buffered by 500 m may represent possible dispersal corridors, and developed land may significantly impede population connectivity in J. roemerianus.Conclusions: Results have important implications for coastal restoration and management that seek to preserve adaptive potential by sustaining natural levels of genetic diversity and conserving population connectivity. Our methodology could be applied to other common, widespread and understudied species. [ABSTRACT FROM AUTHOR]

Abstract: The habitat template concept applied to a freshwater system indicates that lotic species, or those which occupy permanent habitats along stream courses, are less dispersive than lentic species, or those that occur in more ephemeral aquatic habitats. Thus, populations of lotic species will be more structured than those of lentic species. Stream courses include both flowing water and small, stagnant microhabitats that can provide refuge when streams are low. Many species occur in these microhabitats but remain poorly studied. Here, we present population genetic data for one such species, the tropical diving beetle Exocelina manokwariensis (Dytiscidae), sampled from six localities along a ~300 km transect across the Birds Head Peninsula of New Guinea. Molecular data from both mitochondrial (CO1 sequences) and nuclear (ddRAD loci) regions document fine‐scale population structure across populations that are ~45 km apart. Our results are concordant with previous phylogenetic and macroecological studies that applied the habitat template concept to aquatic systems. This study also illustrates that these diverse but mostly overlooked microhabitats are promising study systems in freshwater ecology and evolutionary biology. With the advent of next‐generation sequencing, fine‐scale population genomic studies are feasible for small nonmodel organisms to help illuminate the effect of habitat stability on species’ natural history, population structure and geographic distribution. [ABSTRACT FROM AUTHOR]

Population genetics has increasingly become an important tool for determining appropriate taxonomic units for managing species of conservation interest. Yelloweye rockfish (Sebastes ruberrimus), canary rockfish (S. pinniger) and bocaccio (S. paucispinis) in the inland waterways of Puget Sound (PS), WA, USA were listed under the U.S. Endangered Species Act (ESA) in 2010. These listings relied heavily on evidence from other species that these populations were ‘discrete’ taxonomic units because little information was available for these species in PS. To fill this data gap, we collaborated with recreational fishing communities in PS to collect tissue samples and used population genetics analyses to determine whether samples from PS were genetically differentiated from samples collected from the outer coasts of the U.S. and Canada. Multiple analyses using restriction-site associated DNA sequencing data showed that yelloweye rockfish in PS and British Columbia, Canada were genetically different from coastal populations, while canary rockfish showed no genetic differentiation. These results support hypotheses that the genetic connectivity of rockfish populations is based on interactions between life-history characteristics and oceanographic conditions. These data also support the ESA designation status and the expansion of protected geographical boundaries for yelloweye rockfish but also suggest canary rockfish in PS are not a ‘discrete’ population and may not meet the first criterion of the ESA, as initially assumed. Collaboration among agencies and fishing communities, and cost-efficient genetic analyses provided a framework for collecting and analyzing data essential to the conservation and management of threatened and endangered species. [ABSTRACT FROM AUTHOR]

Due to increasing anthropogenic impacts on deep-sea hydrothermal vent ecosystems, it is essential to understand population structure and maintenance through larval recruitment and recovery of vent faunas after disturbances. In this study, we quantified vent animal recruitment in the Okinawa Trough, in the western Pacific Ocean. This is the first study to investigate recruitment patterns at a man-made hydrothermal vent. Colonization plates were deployed at three sites. Site 1 manifested new hydrothermal shimmering with small chimneys, white bacterial mats, and some alvinocaridid shrimp that arrived after drilling. Site 2 showed no evidence of newly arrived foundation species after drilling, and Site 3 had pre-existing animal communities in the vicinity of the new vent. Twenty-two months after deployment, colonization plates were retrieved and recruited animals were inventoried. Species composition and abundance differed among sites, but relatively high similarity in species composition was observed at Sites 1 and 3, though not at Site 2. Newly established communities on the plates at Sites 1 and 2 (no pre-existing fauna) showed lower species richness and abundance than at Site 3. Differences in abundance and size-frequency distributions of major recruits on the plates (i.e. Lepetodrilus nux , Bathymodiolus spp.) suggest the importance of reproductive and early life-history characteristics in spatial variability of recruitment. Lepetodrilus nux populations established on the plates at Site 1 showed high genetic connectivity. These results illustrate the importance of localized recruitment, which may have a significant impact on sustainability of vent faunal populations, despite the existence of regional metapopulations. [ABSTRACT FROM AUTHOR]

Abstract: Defaunation of large‐bodied frugivores could be causing severe losses of crucial ecosystem functions such as seed dispersal. The immediate ecological consequences may include alteration or even collapse of seed‐mediated gene flow affecting plant population connectivity, with impacts on the regional scale distribution of genetic variation. Yet, these far‐reaching consequences of defaunation remain understudied. Here, we tested whether human‐induced defaunation of the Canarian frugivorous lizards (Gallotia, Lacertidae) altered within‐island population connectivity and the amount and large‐scale distribution of genetic variation of Neochamaelea pulverulenta (Rutaceae), which relies exclusively on these lizards for seed dispersal. Our study system defines a lizard downsizing gradient with three contrasted ecological scenarios (islands) with relatively optimal (Gran Canaria; large‐sized lizards), suboptimal (Tenerife; medium) and collapsed seed dispersal processes (La Gomera; small). We extensively sampled individual plant genotypes from 80 populations spanning the full geographical range of the plant to examine their genetic diversity, population‐genetic network topologies, and the patterns of isolation both by distance (IBD) and resistance (IBR) across these three ecological scenarios. Plant genetic diversity appeared unaffected by defaunation‐mediated downsizing of frugivorous lizards. However, we found a reduced overall plant population connectivity together with an increased isolation by distance within the most defaunated islands (La Gomera and, to a lesser extent, Tenerife) when compared with the scenario preserving the functionality of lizard‐mediated seed dispersal (Gran Canaria). The results, with a significant effect of lizard downsizing, were robust when controlling for biotic/abiotic differences among the three islands by means of isolation by resistance models (IBR). Synthesis. Our results provide valuable insights into the far‐reaching consequences of the deterioration of mutualisms on plant population dynamics over very large spatial scales. Conservation of large‐bodied frugivores is, thus, essential because their irreplaceable mutualistic dispersal services maintain an extensive movement of seeds across the landscape, crucial for maintaining the genetic cohesiveness of metapopulations and the adaptive potential of plant species across their entire geographical range. [ABSTRACT FROM AUTHOR]

Abstract: Populations of broadcast spawning marine organisms often have large sizes and are exposed to reduced genetic drift. Under such scenarios, strong selection associated with spatial environmental heterogeneity is expected to drive localized adaptive divergence, even in the face of connectivity. We tested this hypothesis using a seascape genomics approach in the commercially important greenlip abalone (Haliotis laevigata). We assessed how its population structure has been influenced by environmental heterogeneity along a zonal coastal boundary in southern Australia linked by strong oceanographic connectivity. Our data sets include 9,109 filtered SNPs for 371 abalones from 13 localities and environmental mapping across ~800 km. Genotype–environment association analyses and outlier tests defined 8,786 putatively neutral and 323 candidate adaptive loci. From a neutral perspective, the species is better represented by a metapopulation with very low differentiation (global FST = 0.0081) and weak isolation by distance following a stepping‐stone model. For the candidate adaptive loci, however, model‐based and model‐free approaches indicated five divergent population clusters. After controlling for spatial distance, the distribution of putatively adaptive variation was strongly correlated to selection linked to minimum sea surface temperature and oxygen concentration. Around 80 candidates were annotated to genes with functions related to high temperature and/or low oxygen tolerance, including genes that influence the resilience of abalone species found in other biogeographic regions. Our study includes a documented example about the uptake of genomic information in fisheries management and supports the hypothesis of adaptive divergence due to coastal environmental heterogeneity in a connected metapopulation of a broadcast spawner. [ABSTRACT FROM AUTHOR]

To enhance numerical modeling of the coastal ecosystem complex (CEC), we reviewed the CEC and related concepts along with the current coastal ecosystem model framework in this study. We identified two model implementation paths from the initial objectives to numerical models: specific model building, and the use of existing model frameworks. As the CEC is still at the conceptual stage, both paths are possible. Four important ecological features of CEC modeling (population connectivity, habitat heterogeneity, ontogeny of organisms, and trophic interactions) were also identified. Models for population connectivity, species distributions, life histories, and food webs were categorized using these features. We found that some previously established concepts (between-habitat interactions, coastal ecosystem mosaic, and seascape nursery) overlap with the CEC concept. Several existing integrated model frameworks were reviewed, focusing on their potential to simulate CEC processes. Building specific models for the CEC at the current conceptual stage will be challenging, and modification of existing models will be needed if they are to be used for CEC modeling. Habitat function, ontogenetic development in early life stages, and recruitment variability are important factors when modifying existing models for the development of CEC models. Although model complexity should become high to reproduce observed ecoclogical processes, an intermediate level of model ccomplexity is feasible to decrease parameter uncertainty in models for fisheries management. [ABSTRACT FROM AUTHOR]

Understanding and assessing landscape connectivity is often a primary goal when studying patchy or spatially structured populations. It is commonly accepted that the matrix plays a role in determining connectivity; however, it is not clear how the process of assessing connectivity is impacted by different ways in which the matrix may be represented, particularly if matrix structure is generalized to expedite analysis. We conducted a controlled experiment using computer simulations to evaluate the impact of increasing levels of matrix generalization on connectivity assessment using a constant arrangement of habitat patches. We varied matrix generalization for six simulated landscape patterns by adjusting the number of classes and level of pattern grain in 16 ways to yield sets of landscapes for which the matrix ranged from not generalized (i.e., heterogeneous) to completely generalized (i.e., homogeneous) while habitat placement was held constant. Least-cost paths were calculated for each landscape, and a spatial interaction model (SIM) was implemented to model the counts of patch inflows (immigration) and pairwise exchange. Applying a SIM allowed us to generate absolute outputs and explicitly compare the effect of changes to matrix generalization on connectivity. We found that both assessment of connections (i.e., measured distance and spatial delineation of least-cost paths) and patch inflows/pairwise exchange were highly sensitive to matrix generalization and that effects were inconsistent and unpredictable across the range of matrix representations, especially when estimating connectivity for individual patches. We conclude that matrix pattern may have an underappreciated effect on connectivity and that least-cost path delineation and connectivity assessment may be very sensitive to generalizations of the matrix. We suggest that sensitivity analysis of the matrix representation should be performed when conducting connectivity analyses. [ABSTRACT FROM AUTHOR]

Twenty-eight species of hydroids are now known from Japanese tsunami marine debris (JTMD) sent to sea in March 2011 from the Island of Honshu and landing between 2012 and 2016 in North America and Hawai'i. To 12 JTMD hydroid species previously reported, we add an additional 16 species. Fourteen species (50%) were detected only once; given the small fraction of debris sampled, this suggests that the diversity of the total arriving hydroid fauna was likely larger. Our ongoing studies provide the first documentation of these species being rafted from one continental margin to another. Plumalecium plumularioides (Clark, 1877) is newly reported for the Japanese hydroid fauna. Fourteen species (52%), held to be either naturally amphi-Pacific or possibly introduced by ships at some earlier date, were already known from the Pacific coast of North America. We suggest that Obelia griffini Calkins, 1899, as represented in the JTMD fauna, may be a North Pacific oceanic neustonic species. We propose that Hydrodendron mirabile (Hincks, 1866) and its congeners be included in the family Phylactothecidae Stechow, 1921, here emended. We establish a new family, Plumaleciidae Choong and Calder, 2018, to accommodate the genus Plumalecium Antsulevich, 1982. [ABSTRACT FROM AUTHOR]

Identifying genetic connectivity and discrete population boundaries is an important objective for management of declining Caribbean reef-building corals. A double digest restriction-associated DNA sequencing protocol was utilized to generate 321 single nucleotide polymorphisms to estimate patterns of horizontal and vertical gene flow in the brooding Caribbean plate coral, Agaricia lamarcki. Individual colonies (n = 59) were sampled from eight locations throughout southwestern Puerto Rico from six shallow (~ 10–20 m) and two mesophotic habitats (~ 30–40 m). Descriptive summary statistics (fixation index, FST), analysis of molecular variance, and analysis through landscape and ecological associations and discriminant analysis of principal components estimated high population connectivity with subtle subpopulation structure among all sampling localities. [ABSTRACT FROM AUTHOR]

Southern flounder (Paralichthys lethostigma) from an estuarine complex in the Gulf of Mexico were tagged with acoustic transmitters (n = 60) from 2016 to 2018 to assess estuarine-coastal connectivity during fall/winter spawning runs. Both egress and residency behaviors were observed for adult southern flounder caught in the Galveston Bay Complex (GBC), and individuals were classified as migrators or residents based on their maximum distance detected (MDD). Migrators (MDD >5 km; mean 13.8 km) displayed directed egress out of the GBC, with individuals moving through the tidal pass in November and December, peaking in mid to late December. In contrast, residents (MDD <5 km; mean 0.6 km) showed limited movements and were often detected in the same general area throughout the fall, winter, and spring, indicating overwintering in the GBC. Conventional tagging was also performed on over 1300 southern flounder and mean MDD for all recaptured fish was 5.7 km. Mean monthly MDD of conventionally tagged fish was also highest in December and linked to egress from the GBC. Although directed migrations into the Gulf were observed for southern flounder with both tagging approaches, a meaningful fraction of the population displayed sedentary tendencies with MDD less than 1–2 km and retention within the GBC. The coexistence of two migratory contingents with contrasting estuarine-coastal migration behaviors is symbolic of partial migration by southern flounder, which may influence the resilience and stability of the population. Given that the timing and magnitude of peak egress out of this estuarine complex did not align with management regulations intended to protect spawning adults (i.e., peak movement after reopening of fishery), our findings also indicate the need to extend future closures to protect migrators during the primary egress period. • Directed egress out of an estuarine complex was displayed by adult southern flounder (Paralichthys lethostigma). • Coexistence of two population contingents was observed (resident and migratory), which is indicative of partial migration by this species. • Individuals classified as migrators displayed relatively rapid movements out of the estuary and into the Gulf of Mexico in the late fall. • Residents overwintered within the estuarine complex, and during the spring and summer both classes exhibited little to no movement. • Timing of peak egress out of the estuary did not align with management regulations (i.e., closures) intended to protect spawners. [ABSTRACT FROM AUTHOR]

Mesopelagic fish are largely abundant poorly studied fish that are still intact, but which, due to their potentially great added value, will be imminently exploited by humans. Therefore, studies that provide information to anticipate the anthropogenic impact on this important resource are urgently needed. In particular, knowledge about their connectivity, potential adaptation and resilience are needed. This information can be obtained through the analysis of genome-wide markers which are now relatively easily and cost-efficiently discovered thanks to high-throughput sequencing technologies. Here, we have generated thousands of SNP markers in Maurolicus muelleri, based on the restriction-site associated DNA sequencing method, and preformed population connectivity and genetic diversity analyses in a subset of samples collected from the Bay of Biscay. Our study proves the method valid for obtaining genome-wide markers in this species and provides the first insights into the population genomics of M. muelleri. Importantly, the genomic resources developed here are made available for future studies and set the basics for additional endeavors on this issue.

Small island archipelagos with fringing and dispersed reef systems represent special marine ecosystems, providing a patchy habitat for many coral reef organisms. Although geographic distances may be short, it is still unclear if such environments are inhabited evenly with panmictic conditions or if limited connectivity between marine populations, even on small geographic scales, leads to genetic differentiation between areas within the archipelago or even single reef structures. To study diversity patterns and connectivity between reefs of the Spermonde Archipelago, Indonesia, population genetic analyses of two reef organisms were performed by using the mitochondrial control region and microsatellite markers. A vertebrate (clown anemonefish) and an invertebrate species (sea squirt) were studied in parallel to investigate if there are general patterns of connectivity in Spermonde for sessile or site attached marine species, which can be extrapolated to a larger group. The genetic population structures revealed restrictions in gene flow in the clown anemone fish (Amphiprion ocellaris), especially between near-shore reefs in the South of the archipelago. This indicates very localized genetic exchange and may also reflect the high self-recruitment typical for these fish. The northern reefs show higher connectivity despite geographic distances being larger. The filter-feeding sessile sea squirt, Polycarpa aurata, features similar population patterns, especially in the southern area. However, connectivity is generally higher in the middle and shelf edge areas of Spermonde for this species. The results underline that there are restrictions to gene flow even on very small geographic scales in the studied organisms, with many barriers to gene flow in the southern shallower shelf area. Weaker currents in this area may lead to more influence of biological factors for dispersal, such as larval behavior, motility and competition for suitable habitat. The results are discussed in the context of conservation and MPA planning in the Spermonde Archipelago.