Fire drives animal population dynamics across many ecosystems. Yet, we still lack an understanding of how most species recover from fire and the effects of fire severity and patchiness on recovery ...processes. This information is crucial for fire‐mediated biodiversity conservation, particularly as fire regimes change globally.
We conducted an experiment to test whether post‐fire recovery is driven by in situ survival or recolonisation, and to determine whether this varies with fires of increasing percentage area burnt (burn cover) and severity. We used the pale field rat Rattus tunneyi as a model, because it represents the extinction process for a suite of mammal species suffering population collapse across Australia's northern savannas. Our treatments spanned a gradient from patchy, low severity fires (simulating early dry season management burns) to thorough, high severity fires (simulating wildfires). We performed capture–mark–recapture, vegetation and aerial surveys before, 6 weeks after and 1 year after fire.
Six weeks after fire, pale field rats were only captured in unburnt patches of vegetation, and capture rates were proportional to the amount of unburnt habitat. One year later, both vegetation and pale field rat populations recovered across all sites. However, population recovery after low severity fires was likely achieved through in situ survival and reproduction in unburnt micro‐refuges, compared to recolonisation driving recovery after high severity fires.
Synthesis and applications. Pale field rat persistence is strongly dependent on the retention of unburnt habitat patches within fire‐affected areas. Management strategies that increase micro‐refugia within burnt areas may facilitate pale field rat population recovery. Globally, building recovery mechanisms into fire management will be vital for supporting the long‐term persistence of fire‐affected species.
Pale field rat persistence is strongly dependent on the retention of unburnt habitat patches within fire‐affected areas. Management strategies that increase micro‐refugia within burnt areas may facilitate pale field rat population recovery. Globally, building recovery mechanisms into fire management will be vital for supporting the long‐term persistence of fire‐affected species.
Abstract Measuring genetic diversity of wild species using DNA-based data remains resource intensive and time consuming for nearly all species. However, genetic assessments are needed for global ...conservation commitments, including the Convention on Biological Diversity, and for governments and managers to evaluate conservation progress, as well as prioritizing species and populations to preserve and recover genetic diversity (e.g., via genetic rescue). Recently, indicators were developed for tracking and reporting genetic diversity status and trends for hundreds of species. The indicators quantify two simple proxies of within-population and among-population genetic diversity and adaptive potential: small effective population size (Ne < 500) and the loss of genetically distinct populations. The indicators must balance scientific credibility, practicality, and simplicity. In the present article, we summarize the advantages of these pragmatic indicators, address critiques by scientists for simplifying assumptions and by policymakers for complexity, and propose potential solutions and next steps. We aim to support practitioners putting indicators into policy, action, legislation, and reporting.
Landscape genetics is increasingly transitioning away from microsatellites, with single nucleotide polymorphisms (SNPs) providing increased resolution for detecting patterns of spatial‐genetic ...structure. This is particularly pertinent for research in arid‐zone mammals due to challenges associated with unique life history traits, such as boom‐bust population dynamics and long‐distance dispersal capacities. Here, we provide a case study comparing SNPs versus microsatellites for testing three explicit landscape genetic hypotheses (isolation‐by‐distance, isolation‐by‐barrier, and isolation‐by‐resistance) in a suite of small, arid‐zone mammals in the Pilbara region of Western Australia. Using clustering algorithms, Mantel tests, and linear mixed effects models, we compare functional connectivity between genetic marker types and across species, including one marsupial, Ningaui timealeyi, and two native rodents, Pseudomys chapmani and P. hermannsburgensis. SNPs resolved subtle genetic structuring not detected by microsatellites, particularly for N. timealeyi where two genetic clusters were identified. Furthermore, stronger signatures of isolation‐by‐distance and isolation‐by‐resistance were detected when using SNPs, and model selection based on SNPs tended to identify more complex resistance surfaces (i.e., composite surfaces of multiple environmental layers) in the best‐performing models. While we found limited evidence for physical barriers to dispersal across the Pilbara for all species, we found that topography, substrate, and soil moisture were the main environmental drivers shaping functional connectivity. Our study demonstrates that new analytical and genetic tools can provide novel ecological insights into arid landscapes, with potential application to conservation management through identifying dispersal corridors to mediate the impacts of ongoing habitat fragmentation in the region.
We evaluate landscape connectivity using two different genetic marker types across arid‐zone mammals, which are underrepresented in the landscape genetics literature. We find that topography, substrate, and soil moisture are the main environmental drivers shaping connectivity and that single nucleotide polymorphism (SNP) markers provide finer‐detailed ecological insight. To our knowledge, our study is the first to compare SNPs and microsatellites to empirically test isolation‐by‐resistance hypotheses.
For decades, studies have focused on how dispersal and mating systems influence genetic structure across populations or social groups. However, we still lack a thorough understanding of how these ...processes and their interaction shape spatial genetic patterns over a finer scale (tens—hundreds of metres). Using uniparentally inherited markers may help answer these questions, yet their potential has not been fully explored. Here, we use individual‐level simulations to investigate the effects of dispersal and mating system on fine‐scale genetic structure at autosomal, mitochondrial and Y chromosome markers. Using genetic spatial autocorrelation analysis, we found that dispersal was the major driver of fine‐scale genetic structure across maternally, paternally and biparentally inherited markers. However, when dispersal was restricted (mean distance = 100 m), variation in mating behaviour created strong differences in the comparative level of structure detected at maternally and paternally inherited markers. Promiscuity reduced spatial genetic structure at Y chromosome loci (relative to monogamy), whereas structure increased under polygyny. In contrast, mitochondrial and autosomal markers were robust to differences in the specific mating system, although genetic structure increased across all markers when reproductive success was skewed towards fewer individuals. Comparing males and females at Y chromosome vs. mitochondrial markers, respectively, revealed that some mating systems can generate similar patterns to those expected under sex‐biased dispersal. This demonstrates the need for caution when inferring ecological and behavioural processes from genetic results. Comparing patterns between the sexes, across a range of marker types, may help us tease apart the processes shaping fine‐scale genetic structure.
Genetic diversity is one of the three main levels of biodiversity recognised in the Convention on Biological Diversity (CBD). Fundamental for species adaptation to environmental change, genetic ...diversity is nonetheless under‐reported within global and national indicators. When it is reported, the focus is often narrow and confined to domesticated or other commercial species.
Several approaches have recently been developed to address this shortfall in reporting on genetic diversity of wild species. While multiplicity of approaches is helpful in any development process, it can also lead to confusion among policy makers and heighten a perception that conservation genetics is too to be of use to organisations and governments.
As the developers of five of the different approaches, we have come together to explain how various approaches relate to each other and propose a scorecard, as a unifying reporting mechanism for genetic diversity.
Policy implications. We believe the proposed combined approach captures the strengths of its components and is practical for all nations and subnational governments. It is scalable and can be used to evaluate species conservation projects as well as genetic conservation projects.
مُمُلخص
التنوع الوراثي هو أحد مستويات التنوع البيولوجي الرئيسية الثلاث المُكونة لاتفاقية التنوع البيولوجي الدولية (سي بي دي). رغم أن التنوع الوراثي جانب مهم في تكيف الأنواع والتغير البيئي، إلا أنه عادةً لا يتم التركيز عليه في التقارير الإحيائية الوطنية والعالمية. وغالباً ما يقتصر التركيز على الأنواع الحية الداجنة أو التجارية.
تم مؤخراً تطوير عدة أساليب لمعالجة هذا النقص في التركيز على تضمين التنوع الوراثي للأنواع البرية في التقارير الوطنية. ورغم أن تعدد هذه الأساليب مفيد في أي عملية تطوير، إلا أنه يمكن أن يؤدي أيضًا إلى الارتباك بين صانعي السياسات ويُعطي الانطباع بأن علم الحفاظ الوراثي على الأنواع هو أمر غير أساسي بالتالي قد يتم إغفاله من قِبل المنظمات والحكومات.
كمطورين لخمسة من الأساليب المختلفة لتحديد التنوع الوراثي، فإننا نشرح هنا كيفية ارتباط هذه الأساليب المختلفة ببعضها البعض ونقترح بطاقة قياس الأداء، كآلية إبلاغ موحدة للتنوع الوراثي.
رؤية مستقبلية: نعتقد أن هذا الأسلوب المشترك المُقترح يجسد نقاط القوة في مكوناته وهو عملي لجميع الدول والحكومات المحلية. حيث أنه قابل للتطوير ويمكن استخدامه لتقييم مشاريع الحفاظ على الأنواع الحية وكذلك مشاريع المحافظة على التنوع الوراثي.
Zusammenfassung
Genetische Vielfalt ist eine der drei Säulen der Biodiversität, die im Übereinkommen zum Schutz biologischer Vielfalt definiert wurden. Obwohl die genetische Vielfalt für die Anpassungsfähigkeit von Arten von grundlegender Bedeutung ist, findet sie in nationalen und weltweiten Indikatoren zum Erfassen biologischer Vielfalt kaum Beachtung. Wird dennoch über genetische Vielfalt berichtet beschränkt sie sich häufig auf Arten, die wirtschaftlich bedeutend sind, oder auf die Tier‐ oder Pflanzenzucht.
Innerhalb der letzten Zeit wurden mehrere Ansätze entwickelt, wie diese Vernachlässigung der Berücksichtigung genetischer Vielfalt in den Zustandsberichten zur biologischen Vielfalt verbessert werden können. Verschiedene Ansätze können aber auch zu Verwirrung beitragen und insbesondere bei Entscheidungsträger dazu führen, dass Methoden der Naturschutzgenetik immer noch als zu abstrakt für eine Anwendung angesehen werden.
Hier stellen wir ein einheitliches Bewertungsschema zur Erfassung genetischer Vielfalt vor.
Relevanz. Die Kombination verschiedener Ansätze zur Erfassung genetischer Vielfalt innerhalb eines einheitlichen Bewertungsschemas ermöglicht die Anwendung in allen Ländern und Regionen weltweit. Es kann spezifisch angepasst werden und dient damit auch der Evaluation von Naturschutzprojekten
Riassunto
La diversità genetica è uno dei tre livelli principali della biodiversità come riconosciuto dalla Convenzione sulla Diversità Biologia (CBD). Essa è fondamentale affinchè le specie possano adattarsi ai cambiamenti ambientali, nondimeno all’interno degli indicatori globali e nazionale è sotto rappresentata.
Recentemente sono stati sviluppati molti approcci per risolvere questa lacuna nel riportare i dati sulla diversità genetica delle specie selvatiche. Sebbena la molteplicità degli approccia sia utile in ogni processo di sviluppo, essa può altresì portare a qualche confusione fra i decisori politici ed accrescere la percezione che la genetica della conservazione sia troppo astratta per essere utilizzata dalle organizzazioni e dai governi.
In qualità di sviluppatori di 5 dei diversi approcci, ci siamo riuniti per spiegare come i vari approcci siano reciprocamente correlati e per proporre una ‘carta a punti’, quale meccanismo univoco per riportare i dati sulla diversità genetica.
Implicazioni politiche. Crediamo che la proposta di un approccio combinato catturi la forza di ciascuna delle sue componenti e sia applicabile da tutte le nazioni e dai governi sub‐nazionali. Essa è modulabile e può esser impiegata per valutare i progetti di conservazione così come quelli di genetica della conservazione.
We believe the proposed combined approach captures the strengths of its components and is practical for all nations and subnational governments. It is scalable and can be used to evaluate species conservation projects as well as genetic conservation projects.
Landscape‐scale conservation that considers metapopulation dynamics will be essential for preventing declines of species facing multiple threats to their survival. Toward this end, we developed a ...novel approach that combines occurrence records, spatial–environmental data, and genetic information to model habitat, connectivity, and patterns of genetic structure and link spatial attributes to underlying ecological mechanisms. Using the threatened northern quoll (Dasyurus hallucatus) as a case study, we applied this approach to address the need for conservation decision‐making tools that promote resilient metapopulations of this threatened species in the Pilbara, Western Australia, a multiuse landscape that is a hotspot for biodiversity and mining. Habitat and connectivity were predicted by different landscape characteristics. Whereas habitat suitability was overwhelmingly driven by terrain ruggedness, dispersal was facilitated by proximity to watercourses. Although there is limited evidence for major physical barriers in the Pilbara, areas with high silt and clay content (i.e., alluvial and hardpan plains) showed high resistance to dispersal. Climate subtlety shaped distributions and patterns of genetic turnover, suggesting the potential for local adaptation. By understanding these spatial–environmental associations and linking them to life‐history and metapopulation dynamics, we highlight opportunities to provide targeted species management. To support this, we have created habitat, connectivity, and genetic uniqueness maps for conservation decision‐making in the region. These tools have the potential to provide a more holistic approach to conservation in multiuse landscapes globally.
Resumen
La conservación a nivel del paisaje que incluye las dinámicas metapoblacionales será esencial para prevenir la declinación de especies con múltiples amenazas a su supervivencia. Enfocados en este fin, desarrollamos una estrategia novedosa que combina los registros presenciales, datos espacio‐ambientales e información genética para modelar la conectividad de hábitat y los patrones de estructura genética y conectar los atributos espaciales con los mecanismos ecológicos subyacentes. Usamos al cuol del norte (Dasyurus hallucatus) como estudio de caso para aplicar esta estrategia y abordar la necesidad de herramientas de decisión en la conservación que promuevan metapoblaciones resilientes de esta especie en la Pilbara de Australia Occidental, un paisaje multiusos que es un punto caliente para la biodiversidad y la minería. Diferentes características del paisaje pronosticaron la conectividad y el hábitat. Mientras que la escabrosidad del terreno causó enormemente la idoneidad del hábitat, la dispersión estuvo propiciada por la proximidad a los cauces. Aunque hay evidencias limitadas de barreras físicas importantes en la Pilbara, las áreas con un contenido elevado de limo y arcilla (es decir, planicies aluviales y de alio) mostraron una gran resistencia a la dispersión. La matización climática determinó la distribución y los patrones del recambio genético, lo que sugiere un potencial para la adaptación local. Si entendemos estas asociaciones espacio‐ambientales y las conectamos con las dinámicas metapoblacionales y de historia de vida, podemos resaltar las oportunidades para proporcionar un manejo focalizado de la especie. Para respaldar esto hemos creado mapas de hábitat, conectividad y singularidad genética para las decisiones de conservación en la región. Estas herramientas tienen el potencial de proporcionar una estrategia más holística para la conservación en los paisajes multiusos de todo el mundo.
The Coalition for Conservation Genetics (CCG) brings together four eminent organizations with the shared goal of improving the integration of genetic information into conservation policy and ...practice. We provide a historical context of conservation genetics as a field and reflect on current barriers to conserving genetic diversity, highlighting the need for collaboration across traditional divides, international partnerships, and coordinated advocacy. We then introduce the CCG and illustrate through examples how a coalition approach can leverage complementary expertise and improve the organizational impact at multiple levels. The CCG has proven particularly successful at implementing large synthesis‐type projects, training early‐career scientists, and advising policy makers. Achievements to date highlight the potential for the CCG to make effective contributions to practical conservation policy and management that no one “parent” organization could achieve on its own. Finally, we reflect on the lessons learned through forming the CCG, and our vision for the future.
Background. Malaria remains a major cause of global mortality. Extracellular heme, released during malaria-induced hemolysis, mediates a number of pathogenic processes associated with vascular and ...organ injury. Hemopexin (hpx) facilitates the degradation of extracellular heme. In this study, we explore the hypothesis that dysregulation of the heme-hpx axis is associated with disease severity, acute kidney injury (AKI), and outcome. Methods. Plasma levels of hemin and hpx (at admission, day 3, and day 14) were assessed in children with severe malaria in Jinja, Uganda. Results. The ratio of heme to hpx was higher at admission and decreased with recovery (median, 0.043 interquartile range {IQR}, 0.007-0.239 on day 1, 0.024 IQR, 0.005-0.126 on day 3, and 0.008 IQR, 0.002-0.022 on day 14; P<.001). Ratios of heme to hpx at admission were higher in children with as compared to those without severe anemia (median, 0.124 IQR, 0.024-0.431 vs 0.016 IQR, 0.003-0.073; P<.0001), children with as compared to those without respiratory distress (median, 0.063 IQR, 0.017-0.413 vs 0.020 IQR, 0.004-0.124; P<.01), and children with as opposed to those without stage 3 AKI (median, 0.354 IQR, 0.123-2.481 vs 0.037 IQR, 0.005-0.172, P<.01). The heme to hpx ratio at admission was associated with 6-month mortality (median, 0.148 IQR, 0.042-0.500 vs 0.039 IQR, 0.007-0.172; P = .012). Conclusions. The ratio of heme to hpx is associated with disease severity and adverse clinical outcomes in Ugandan children, and dysregulation of the heme axis may contribute to malaria pathogenesis.
Ecological disturbance and climate are key drivers of temporal dynamics in the demography and genetic diversity of natural populations. Microscale refuges are known to buffer species’ persistence ...against environmental change, but the effects of such refuges on demographic and genetic patterns in response to short‐term environmental variation are poorly understood. We quantified demographic and genetic responses of mountain brushtail possums (Trichosurus cunninghami) to rainfall variability (1992–2013) and to a major wildfire. We hypothesized that there would be underlying differences in demographic and genetic processes between an unburnt mesic refuge and a topographically exposed zone that was burnt in 2009. Fire caused a 2‐year decrease in survival in the burnt zone, but the population grew after the fire due to immigration, leading to increased expected heterozygosity. We documented a fire‐related behavioural shift, where the rate of movement by individuals in the unburnt refuge to the burnt zone decreased after fire. Irrespective of the fire, there were long‐term differences in demographic and genetic parameters between the mesic/unburnt refuge and the nonmesic/burnt zone. Survival was high and unaffected by rainfall in the refuge, but lower and rainfall‐dependent in the nonmesic zone. Net movement of individuals was directional, from the mesic refuge to the nonmesic zone, suggesting fine‐scale source–sink dynamics. There were higher expected heterozygosity (HE) and temporal genetic stability in the refuge, but lower HE and marked temporal genetic structure in the exposed habitat, consistent with reduced generational overlap caused by elevated mortality and immigration. Thus, fine‐scale refuges can mediate the short‐term demographic and genetic effects of climate and ecological disturbance.
Introduction: Susceptibility to amyotrophic lateral sclerosis (ALS) is associated with smoking in some studies, but it is not clear which aspect of smoking behavior is related. Using detailed records ...of lifetime smoking we investigated the relationship between smoking and ALS in a UK population. Methods: In this retrospective case-control study, smoking status was collected using environmental questionnaires from people diagnosed with ALS between 2008 and 2013 and from age, sex and geographically matched controls. Categorical measures of smoking behavior were: smoking at the time of survey and smoking initiation; continuous measures were intensity (cigarettes per day), duration (years from starting to stopping or time of survey), cigarette pack years, and comprehensive smoking index (CSI), a measure of lifetime smoking. We used logistic regression to assess the risk of ALS with different combinations of smoking variables adjusted for age at survey, gender, level of education, smoking status and alcohol initiation, selecting the best model using the Akaike Information Criterion. Results: There were 388 records with full smoking history. The best-fitting model used CSI and smoking status at the time of survey. We found a weak association between current smoking and risk of ALS, OR 3.63 (95% CI 1.02-13.9) p value 0.05. Increase in CSI score did not increase risk of ALS: OR 0.81 (95% CI 0.58-1.11) p value 0.2.Conclusion: There is weak evidence of a positive effect of current smoking on the risk of ALS which does not show dose-dependence with higher levels of lifetime smoking and maybe a false positive result.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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