Cultivating Resilience in Dryland Soils: An Assisted Migration Approach to Biological Soil Crust Restoration.

Land use practices and climate change have driven substantial soil degradation across global drylands, impacting ecosystem functions and human livelihoods. Biological soil crusts, a common feature of dryland ecosystems, are under extensive exploration for their potential to restore the stability and fertility of degraded soils through the development of inoculants. However, stressful abiotic conditions often result in the failure of inoculation-based restoration in the field and may hinder the long-term success of biocrust restoration efforts. Taking an assisted migration approach, we cultivated biocrust inocula sourced from multiple hot-adapted sites (Mojave and Sonoran Deserts) in an outdoor facility at a cool desert site (Colorado Plateau). In addition to cultivating inoculum from each site, we created an inoculum mixture of biocrust from the Mojave Desert, Sonoran Desert, and Colorado Plateau. We then applied two habitat amelioration treatments to the cultivation site (growth substrate and shading) to enhance soil stability and water availability and reduce UV stress. Using marker gene sequencing, we found that the cultivated mixed inoculum comprised both local- and hot-adapted cyanobacteria at the end of cultivation but had similar cyanobacterial richness as each unmixed inoculum. All cultivated inocula had more cyanobacterial 16S rRNA gene copies and higher cyanobacterial richness when cultivated with a growth substrate and shade. Our work shows that it is possible to field cultivate biocrust inocula sourced from different deserts, but that community composition shifts toward that of the cultivation site unless habitat amelioration is employed. Future assessments of the function of a mixed inoculum in restoration and its resilience in the face of abiotic stressors are needed to determine the relative benefit of assisted migration compared to the challenges and risks of this approach.

Reforestation of high elevation pines: Direct seeding success depends on seed source and sowing environment.

Forest persistence in regions impacted by increasing water and temperature stress will depend upon species' ability to either rapidly adjust to novel conditions or migrate to track ecological niches. Predicted, rapid climate change is likely to outpace the adaptive and migratory capacity of long-lived isolated tree species, and reforestation may be critical to species' persistence. Facilitating persistence both within and beyond a species' range requires identification of seed lots best adapted to the current and future conditions predicted with rapid climate change. We evaluate variation in emergent seedling performance that leads to differential survival among species and populations for three high elevation five-needle pines. We paired a fully reciprocal field common garden experiment with a greenhouse common garden study to (1) quantify variation in seedling emergence and functional traits, (2) ask how functional traits affect performance under different establishment conditions, and (3) evaluate whether trait and performance variation demonstrates local adaptation and plasticity. Among study species-limber, Great Basin bristlecone, and whitebark pines-we found divergence in emergence and functional traits, though soil moisture was the strongest driver of seedling emergence and abundance across all species. Generalist limber pine had a clear emergence advantage as well as traits associated with drought adaptation, while edaphic specialist bristlecone pine was characterized by low emergence yet high early survival once established. Despite evidence for edaphic specialization, soil characteristics alone did not explain bristlecone success. Across species, trait-environment relationships provided some evidence for local adaptation in drought-adapted traits, but we found no evidence of local adaptation in emergence or survival at this early life stage. For managers looking to promote persistence, sourcing seed from drier environments is likely to impart greater drought resistance into reforestation efforts through strategies such as greater root investment, increasing the probability of early seedling survival. This research demonstrates, through a rigorous reciprocal transplant experimental design, that it may be possible to select climate- and soil-appropriate seed sources for reforestation. However, planting success will ultimately rely on a suitable establishment environment, requiring careful consideration of interannual climate variability for management interventions in these climate and disturbance-impacted tree species.

Assessment of the impact of climate change on endangered conifer tree species by considering climate and soil dual suitability and interspecific competition.

Climate change results in the habitat loss of many conifer tree species and jeopardizes species biodiversity and forest ecological functions. Delineating suitable habitats for tree species via climate niche model (CNM) is widely used to predict the impact of climate change and develop conservation and management strategies. However, the robustness of CNM is broadly debated as it usually does not consider soil and competition factors. Here we developed a new approach to combine soil variables with CNM and evaluate interspecific competition potential in the niche overlapping areas. We used an endangered conifer species - Chamaecyparis formosensis (red cypress) - as a case study to predict the impact of climate change. We developed a novel approach to integrate the climate niche model and soil niche model predictions and considered interspecific competition to predict the impacts of climate change on tree species. Our results show that the suitable habitat for red cypress would decrease significantly in the future with an additional threat from the competition of an oak tree species. Our approach and results may represent significant implications in making conservation strategies and evaluating the impacts of climate change, and providing the direction of the refinement of the ecological niche model.

Genetic rescue remains underused for aiding recovery of federally listed vertebrates in the United States.

Restoring gene flow among fragmented populations is discussed as a potentially powerful management strategy that could reduce inbreeding depression and cause genetic rescue. Yet, examples of assisted migration for genetic rescue remain sparse in conservation, prompting several outspoken calls for its increased use in genetic management of fragmented populations. We set out to evaluate the extent to which this strategy is underused and to determine how many imperiled species would realistically stand to benefit from genetic rescue, focusing on federally threatened or endangered vertebrate species in the United States. We developed a "genetic rescue suitability index (GR index)" based on concerns about small population problems relative to risks associated with outbreeding depression and surveyed the literature for 222 species. We found that two-thirds of these species were good candidates for consideration of assisted migration for the purpose of genetic rescue according to our suitability index. Good candidate species spanned all taxonomic groups and geographic regions, though species with more missing data tended to score lower on the suitability index. While we do not recommend a prescriptive interpretation of our GR index, we used it here to establish that assisted migration for genetic rescue is an underused strategy. For example, we found in total, "genetic rescue" was only mentioned in 11 recovery plans and has only been implemented in 3 of the species we surveyed. A potential way forward for implementation of this strategy is incorporating genetic rescue as a priority in USFWS recovery documentation. In general, our results suggest that although not appropriate for all imperiled species, many more species stand to benefit from a conservation strategy of assisted migration for genetic rescue than those for which it has previously been considered or implemented.

How Should We Help Wild Animals Cope with Climate Change? The Case of the Iberian Lynx.

Climate change and related shifts in weather conditions result in massive biodiversity declines and severe animal suffering. This article explores the measures that can be taken to decrease animal suffering and prevent species from going extinct. Taking the Iberian lynx as a case study, we assess the extent to which it is beneficial for animal welfare and species conservation to do nothing or reduce other threats, provide food or shelter, relocate the species via assisted migration, or bring the population into captivity. We argue that, given the Iberian lynx's non-invasive characteristics, assisted migration may be the best way to protect the species while ensuring animal welfare and protecting wildness and other ecosystem values.

Genomic analyses point to a low evolutionary potential of prospective source populations for assisted migration in a forest herb.

Climate change is increasingly impacting temperate forest ecosystems and many forest herbs might be unable to track the changing climate due to dispersal limitation. Forest herbs with a low adaptive capacity may therefore benefit from conservation strategies that mitigate dispersal limitation and evolutionary constraints, such as assisted migration. However, assisted migration strategies rarely consider evolutionary constraints of potential source populations that may jeopardize their success. In cases where climate adaptation is overshadowed by competing evolutionary processes, assisted migration is unlikely to support adaptation to future climates. Using a combination of population and landscape genomic analyses, we disentangled local adaptation drivers and quantified the adaptability and vulnerability to climate change of the self-incompatible deciduous forest herb Primula elatior. Southern populations displayed a sharp genetic turnover and a considerable amount of local adaptation under diversifying selection was discovered. However, most of the outlier loci could not be linked to climate variables (71%) and were likely related to other local adaptation drivers, such as photoperiodism. Furthermore, specific adaptations to climate extremes, such as drought stress, could not be detected. This is in line with the typical occurrence of forest herbs in buffered climatic conditions, which can be expected to reduce selection pressures imposed by climate. Finally, populations in the south of the distribution area had increased sensitivity to climate change due to a reduced adaptive capacity and a moderate genetic offset, while central European populations were sensitive due to a high genetic offset. We conclude that assisted migration from southern source populations could bear significant risk due to nonclimatic maladaptation and a low adaptive capacity. Regional admixture and restoration of ecological connectivity to increase the adaptive capacity, and assisted range expansion to suitable habitat in the north might be more appropriate mitigation strategies.

Assisted migration is plausible for a boreal tree species under climate change: A quantitative and population genetics study of trembling aspen (Populus tremuloides Michx.) in western Canada.

A novel method was tested for improving tree breeding strategies that integrate quantitative and population genetics based on range-wide reciprocal transplant experiments. Five reciprocal common garden tests of Populus tremuloides were investigated including 6450 trees across western Canada focusing on adaptation traits and growth. Both genetic parameters and home-site transplant models were evaluated. We found a genetic trade-off between growth and early spring leaf flush and late fall senescence. Coefficients of phenotypic variation (CVp) of cell lysis (CL), a measure of freezing injury, shrank from 0.28 to 0.10 during acclimation in the fall, and the CVp slope versus the freezing temperature was significantly different from zero (R 2 = 0.33, p = .02). There was more between-population genetic variation in fall phenology than in spring leaf phenology. We suggest that P. tremuloides demonstrated a discrepancy between the ecological optimum and the physiological optimum minimum winter temperature. The sub-optimal growing condition of P. tremuloides is potentially caused by the warmer ecological optimum than the physiological optimum. Assisted migration and breeding of fast growers to reforest cooler plantation sites can improve productivity. Transferring the study populations to less than 4°C of extreme minimum temperature appears safe for reforestation aligning with the historical recolonization direction of the species. This is equivalent to a 5-10° latitudinal northward movement. Fall frost hardiness is an effective criterion for family selection in the range tested in this study.

Leaf Economic and Hydraulic Traits Signal Disparate Climate Adaptation Patterns in Two Co-Occurring Woodland Eucalypts.

With climate change impacting trees worldwide, enhancing adaptation capacity has become an important goal of provenance translocation strategies for forestry, ecological renovation, and biodiversity conservation. Given that not every species can be studied in detail, it is important to understand the extent to which climate adaptation patterns can be generalised across species, in terms of the selective agents and traits involved. We here compare patterns of genetic-based population (co)variation in leaf economic and hydraulic traits, climate-trait associations, and genomic differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-year-old trees growing in a common-garden trial established with progeny from populations of both species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania, Australia. Despite originating from the same climatic gradients, the species differed in their levels of population variance and trait covariance, patterns of population variation within each species were uncorrelated, and the species had different climate-trait associations. Further, the pattern of genomic differentiation among populations was uncorrelated between species, and population differentiation in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to explain this decoupling of patterns and propose that the choice of seed provenances for climate-based plantings needs to account for multiple dimensions of climate change unless species-specific information is available.

Strategies to mitigate shifts in red oak (Quercus sect. Lobatae) distribution under a changing climate.

Red oaks (Quercus sect. Lobatae) are a taxonomic group of hardwood trees, which occur in swamp forests, subtropical chaparral and savannahs from Columbia to Canada. They cover a wide range of ecological niches, and many species are thought to be able to cope with current trends in climate change. Genus Quercus encompasses ca. 500 species, of which ca. 80 make up sect. Lobatae. Species diversity is greatest within the southeastern USA and within the northern and eastern regions of Mexico. This review discusses the weak reproductive barriers between species of red oaks and the effects this has on speciation and niche range. Distribution and diversity have been shaped by drought adaptations common to the species of sect. Lobatae, which enable them to fill various xeric niches across the continent. Drought adaptive traits of this taxonomic group include deciduousness, deep tap roots, ring-porous xylem, regenerative stump sprouting, greater leaf thickness and smaller stomata. The complex interplay between these anatomical and morphological traits has given red oaks features of drought tolerance and avoidance. Here, we discuss physiological and genetic components of these adaptations to address how many species of sect. Lobatae reside within xeric sites and/or sustain normal metabolic function during drought. Although extensive drought adaptation appears to give sect. Lobatae a resilience to climate change, aging tree stands, oak life history traits and the current genetic structures place many red oak species at risk. Furthermore, oak decline, a complex interaction between abiotic and biotic agents, has severe effects on red oaks and is likely to accelerate species decline and fragmentation. We suggest that assisted migration can be used to avoid species fragmentation and increase climate change resilience of sect. Lobatae.

Comparing management strategies for conserving communities of climate-threatened species with a stochastic metacommunity model.

Many species are shifting their ranges to keep pace with climate change, but habitat fragmentation and limited dispersal could impede these range shifts. In the case of climate-vulnerable foundation species such as tropical reef corals and temperate forest trees, such limitations might put entire communities at risk of extinction. Restoring connectivity through corridors, stepping-stones or enhanced quality of existing patches could prevent the extinction of several species, but dispersal-limited species might not benefit if other species block their dispersal. Alternatively, managers might relocate vulnerable species between habitats through assisted migration, but this is generally a species-by-species approach. To evaluate the relative efficacy of these strategies, we simulated the climate-tracking of species in randomized competitive metacommunities with alternative management interventions. We found that corridors and assisted migration were the most effective strategies at reducing extinction. Assisted migration was especially effective at reducing the extinction likelihood for short-dispersing species, but it often required moving several species repeatedly. Assisted migration was more effective at reducing extinction in environments with higher stochasticity, and corridors were more effective at reducing extinction in environments with lower stochasticity. We discuss the application of these approaches to an array of systems ranging from tropical corals to temperate forests. This article is part of the theme issue 'Ecological complexity and the biosphere: the next 30 years'.

The immediate costs and long-term benefits of assisted gene flow in large populations.

With the genetic health of many plant and animal populations deteriorating due to climate change outpacing adaptation, interventions, such as assisted gene flow (AGF), may provide genetic variation necessary for populations to adapt to climate change. We ran genetic simulations to mimic different AGF scenarios in large populations and measured their outcomes on population-level fitness to determine circumstances in which it is worthwhile to perform AGF. In the absence of inbreeding depression, AGF was beneficial within a few generations only when introduced genotypes had much higher fitness than local individuals and traits affecting fitness were controlled by a few genes of large effect. AGF was harmful over short periods (e.g., first ∼10-20 generations) if there was strong outbreeding depression or introduced deleterious genetic variation. When the adaptive trait was controlled by many loci of small effect, the benefits of AGF took over 10 generations to realize-potentially too long for most climate-related management scenarios. The genomic integrity of the recipient population typically remained intact following AGF; the amount of genetic material from the donor population usually constituted no more of the recipient population's genome than the fraction of the population introduced. Significant genomic turnover (e.g., >50% replacement) only occurred when the selective advantage of the adaptive trait and translocation fraction were extremely high. Our results will be useful when adaptive management is used to maintain the genetic health and productivity of large populations under climate change.

Con el deterioro de la salud genética de muchas poblaciones de plantas y animales debido a la ventaja que le lleva el cambio climático a la adaptación, algunas intervenciones, como el flujo génico asistido (FGA), pueden proporcionar la variación genética necesaria para que las poblaciones se adapten al cambio climático. Simulamos diferentes escenarios de FGA aplicado en poblaciones grandes y medimos los resultados en la aptitud a nivel poblacional para determinar las circunstancias en las que merece la pena realizar FGA. Cuando no hubo depresión endogámica, el FGA produjo un beneficio en pocas generaciones sólo cuando se introdujeron genotipos que tenían una aptitud mucho mayor que los individuos locales y cuando unos cuantos genes de gran efecto controlaron los rasgos que afectaban a la aptitud. El flujo génico asistido fue dañino en periodos cortos (p.ej.: las primeras 10-20 generaciones) si existía una fuerte depresión exogámica o una variación genética deletérea introducida. Cuando muchos loci de pequeño efecto controlaron el rasgo adaptativo, los beneficios del FGA tardaron más de 10 generaciones en aparecer - un tiempo potencialmente muy largo para la mayoría de la gestión relacionada con el clima. La integridad genómica de la población receptora casi siempre permaneció intacta después del FGA; es decir, la cantidad de material genético de la población donante generalmente no constituyó más que la fracción de población introducida en el genoma de la población receptora. La rotación genómica significativa (p.ej.: reemplazos >50%) sólo ocurrió cuando la ventaja selectiva del rasgo adaptativo y la fracción de reubicación fueron extremadamente elevadas. Nuestros resultados serán útiles cuando se use la gestión adaptativa para mantener la salud genética y la productividad de las poblaciones grandes bajo el cambio climático.

Current Conservation Regimes and the Road to Laws on Assisted Migration.

The negative impact of climate change on biodiversity will continue to escalate rapidly. While some species will naturally migrate to more suitable areas or adapt to the new climatic environmental conditions in different fashions, for others doing so may prove to be problematic or impossible. Against this backdrop, scientists and environmentalists have proposed implementing plans for Assisted Migration (AM)-meaning the translocation of plants and animals to areas outside their natural habitats to conserve their species under the new emerging climatic conditions. This article seeks to identify legal approaches towards AM considering not only possible benefits from using this tool but also a necessity to minimize related risks. With regard to its stated purpose, this article also compares legal and policy documents relevant to AM issues from the United States, Australia, and the European Union. In conclusion, we have found, and this article shows, that while existing legal and policy documents leave room for manoeuvreing in regard to climate-related translocations and even sometimes explicitly mention AM as a possible tool for conservation, there exists a need for the further development of concrete legal mechanisms and their balancing with the predominant ideas and goals brought about by the necessity to protect native biota.

Applying genomics in assisted migration under climate change: Framework, empirical applications, and case studies.

The rate of global climate change is projected to outpace the ability of many natural populations and species to adapt. Assisted migration (AM), which is defined as the managed movement of climate-adapted individuals within or outside the species ranges, is a conservation option to improve species' adaptive capacity and facilitate persistence. Although conservation biologists have long been using genetic tools to increase or maintain diversity of natural populations, genomic techniques could add extra benefit in AM that include selectively neutral and adaptive regions of the genome. In this review, we first propose a framework along with detailed procedures to aid collaboration among scientists, agencies, and local and regional managers during the decision-making process of genomics-guided AM. We then summarize the genomic approaches for applying AM, followed by a literature search of existing incorporation of genomics in AM across taxa. Our literature search initially identified 729 publications, but after filtering returned only 50 empirical studies that were either directly applied or considered genomics in AM related to climate change across taxa of plants, terrestrial animals, and aquatic animals; 42 studies were in plants. This demonstrated limited application of genomic methods in AM in organisms other than plants, so we provide further case studies as two examples to demonstrate the negative impact of climate change on non-model species and how genomics could be applied in AM. With the rapidly developing sequencing technology and accumulating genomic data, we expect to see more successful applications of genomics in AM, and more broadly, in the conservation of biodiversity.

Difficult climate-adaptive decisions in forests as complex social-ecological systems.

Climate change threatens the social, ecological, and economic benefits enjoyed by forest-dependent communities worldwide. Climate-adaptive forest management strategies such as genomics-based assisted migration (AM) may help protect many of these threatened benefits. However, such novel technological interventions in complex social-ecological systems will generate new risks, benefits, and uncertainties that interact with diverse forest values and preexisting risks. Using data from 16 focus groups in British Columbia, Canada, we show that different stakeholders (forestry professionals, environmental nongovernmental organizations, local government officials, and members of local business communities) emphasize different kinds of risks and uncertainties in judging the appropriateness of AM. We show the difficulty of climate-adaptive decisions in complex social-ecological systems in which both climate change and adaptation will have widespread and cascading impacts on diverse nonclimate values. Overarching judgments about AM as an adaptation strategy, which may appear simple when elicited in surveys or questionnaires, require that participants make complex trade-offs among multiple domains of uncertain and unknown risks. Overall, the highest-priority forest management objective for most stakeholders is the health and integrity of the forest ecosystem from which all other important forest values derive. The factor perceived as riskiest is our lack of knowledge of how forest ecosystems work, which hinders stakeholders in their assessment of AM's acceptability. These results are further evidence of the inherent risk in privileging natural science above other forms of knowledge at the science-policy interface. When decisions are framed as technical, the normative and ethical considerations that define our fundamental goals are made invisible.

Of mutualism and migration: will interactions with novel ericoid mycorrhizal communities help or hinder northward Rhododendron range shifts?

Rapid climate change imperils many small-ranged endemic species as the climate envelopes of their native ranges shift poleward. In addition to abiotic changes, biotic interactions are expected to play a critical role in plant species' responses. Below-ground interactions are of particular interest given increasing evidence of microbial effects on plant performance and the prevalence of mycorrhizal mutualisms. We used greenhouse mesocosm experiments to investigate how natural northward migration/assisted colonization of Rhododendron catawbiense, a small-ranged endemic eastern U.S. shrub, might be influenced by novel below-ground biotic interactions from soils north of its native range, particularly with ericoid mycorrhizal fungi (ERM). We compared germination, leaf size, survival, and ERM colonization rates of endemic R. catawbiense and widespread R. maximum when sown on different soil inoculum treatments: a sterilized control; a non-ERM biotic control; ERM communities from northern R. maximum populations; and ERM communities collected from the native range of R. catawbiense. Germination rates for both species when inoculated with congeners' novel soils were significantly higher than when inoculated with conspecific soils, or non-mycorrhizal controls. Mortality rates were unaffected by treatment, suggesting that the unexpected reciprocal effect of each species' increased establishment in association with heterospecific ERM could have lasting demographic effects. Our results suggest that seedling establishment of R. catawbiense in northern regions outside its native range could be facilitated by the presence of extant congeners like R. maximum and their associated soil microbiota. These findings have direct relevance to the potential for successful poleward migration or future assisted colonization efforts.

Do southern seed or soil microbes mitigate the effects of warming on establishing prairie plant communities?

Restoration in this era of climate change comes with a new challenge: anticipating how best to restore populations to persist under future climate conditions. Specifically, it remains unknown whether locally adapted or warm-adapted seeds best promote native plant community restoration in the warmer conditions predicted in the future and whether local or warm-adapted soil microbial communities could mitigate plant responses to warming. This may be especially relevant for biomes spanning large climatic gradients, such as the North American tallgrass prairie. Here, we used a short-term mesocosm experiment to evaluate how seed provenances (Local Northern region, Non-local Northern region, Non-local Southern region) of 10 native tallgrass prairie plants (four forbs, two legumes, and four grasses) responded to warmer conditions predicted in the future and how soil microbial communities from those three regions influenced these responses. Warming and seed provenance affected plant community composition and warming decreased plant diversity for all three seed provenances. Plant species varied in their individual responses to warming, and across species, we detected no consistent differences among the three provenances in terms of biomass response to warming and few strong effects of soil provenance. Our work provides evidence that warming, in part, may reduce plant diversity and affect restored prairie composition. Because the southern provenance did not consistently outperform others under warming and we found little support for the "local is best" paradigm currently dominating restoration practice, identifying appropriate seed provenances to promote restoration success both now and in future warmer environments may be challenging. Due to the idiosyncratic responses across species, we recommend that land managers compare seeds from different regions for each species to determine which seed provenance performs best under warming and in restoration for tallgrass prairies.

Evaluating unintended consequences of intentional species introductions and eradications for improved conservation management.

Increasingly intensive strategies to maintain biodiversity and ecosystem function are being deployed in response to global anthropogenic threats, including intentionally introducing and eradicating species via assisted migration, rewilding, biological control, invasive species eradications, and gene drives. These actions are highly contentious because of their potential for unintended consequences. We conducted a global literature review of these conservation actions to quantify how often unintended outcomes occur and to elucidate their underlying causes. To evaluate conservation outcomes, we developed a community assessment framework for systematically mapping the range of possible interaction types for 111 case studies. Applying this tool, we quantified the number of interaction types considered in each study and documented the nature and strength of intended and unintended outcomes. Intended outcomes were reported in 51% of cases, a combination of intended outcomes and unintended outcomes in 26%, and strictly unintended outcomes in 10%. Hence, unintended outcomes were reported in 36% of all cases evaluated. In evaluating overall conservations outcomes (weighing intended vs. unintended effects), some unintended effects were fairly innocuous relative to the conservation objective, whereas others resulted in serious unintended consequences in recipient communities. Studies that assessed a greater number of community interactions with the target species reported unintended outcomes more often, suggesting that unintended consequences may be underreported due to insufficient vetting. Most reported unintended outcomes arose from direct effects (68%) or simple density-mediated or indirect effects (25%) linked to the target species. Only a few documented cases arose from more complex interaction pathways (7%). Therefore, most unintended outcomes involved simple interactions that could be predicted and mitigated through more formal vetting. Our community assessment framework provides a tool for screening future conservation actions by mapping the recipient community interaction web to identify and mitigate unintended outcomes from intentional species introductions and eradications for conservation.

Evaluación de las Consecuencias Involuntarias de las Introducciones y Erradicaciones Intencionales de Especies para el Manejo Mejorado de la Conservación Resumen Actualmente se despliegan estrategias cada vez más intensas para mantener la biodiversidad y la función del ecosistema como respuesta a las amenazas antropogénicas mundiales, incluyendo la introducción y erradicación intencionales de especies por medio de la migración asistida, el retorno a la vida silvestre, el control biológico, la erradicación de especies invasoras y la genética dirigida. Estas acciones son muy polémicas por el potencial que tienen para generar consecuencias involuntarias. Realizamos una revisión de la literatura mundial sobre estas acciones de conservación para cuantificar cuán seguido ocurren las consecuencias involuntarias y cuáles son sus causas subyacentes. Para evaluar los resultados de conservación, desarrollamos un marco de trabajo de evaluación comunitaria para mapear sistemáticamente el rango de posibles interacciones para 111 estudios de caso. Con la aplicación de esta herramienta cuantificamos el número de tipos de interacción consideradas en cada estudio y documentamos la naturaleza y la fuerza de los resultados involuntarios. Se reportaron los resultados voluntarios en 51% de los casos, una combinación de resultados voluntarios e involuntarios en 26% de los casos y estrictamente los resultados involuntarios en el 10% de los casos. Por lo tanto, los resultados involuntarios fueron reportados en el 36% de todos los casos evaluados. En la evaluación general de los resultados de conservación (sopesando los efectos voluntarios y. los involuntarios), algunos efectos involuntarios fueron bastante inocuos en relación con el objetivo de conservación, mientras que otros resultaron en consecuencias involuntarias severas para las comunidades receptoras. Los estudios que evaluaron un mayor número de interacciones comunitarias con la especie objetivo reportaron resultados involuntarios con mayor frecuencia, lo que sugiere que las consecuencias involuntarias pueden estar subvaloradas debido al escrutinio insuficiente. La mayoría de los resultados involuntarios reportados surgieron de los efectos directos (68%) o de los efectos indirectos o mediados por la densidad (25%) vinculados con la especie diana. Solamente unos cuantos casos documentados surgieron de interacciones más complejas (7%). Por lo tanto, la mayoría de los resultados involuntarios involucran interacciones simples que podrían ser pronosticadas y mitigadas por medio de un escrutinio más formal. Nuestro marco de trabajo de evaluación comunitaria proporciona una herramienta para la revisión de las acciones de conservación en el futuro mediante el mapeo de la red de interacciones entre comunidades receptoras y para la mitigación de los resultados involuntarios surgidos de las introducciones y erradicaciones intencionales de especies a favor de la conservación.

Accelerating Adaptation of Forest Trees to Climate Change Using Individual Tree Response Functions.

In forest tree breeding, assisted migration has been proposed to accelerate the adaptive response to climate change. Response functions are currently fitted across multiple populations and environments, enabling selections of the most appropriate seed sources for a specific reforestation site. So far, the approach has been limited to capturing adaptive variation among populations, neglecting tree-to-tree variation residing within a population. Here, we combined the response function methodology with the in-situ breeding approach, utilizing progeny trials of European larch (Larix decidua) across 21 test sites in Austria ranging from Alpine to lowland regions. We quantified intra-population genetic variance and predicted individual genetic performance along a climatic gradient. This approach can be adopted in most breeding and conservation programs, boosting the speed of adaptation under climate change.

Genomic Approaches for Conservation Management in Australia under Climate Change.

Conservation genetics has informed threatened species management for several decades. With the advent of advanced DNA sequencing technologies in recent years, it is now possible to monitor and manage threatened populations with even greater precision. Climate change presents a number of threats and challenges, but new genomics data and analytical approaches provide opportunities to identify critical evolutionary processes of relevance to genetic management under climate change. Here, we discuss the applications of such approaches for threatened species management in Australia in the context of climate change, identifying methods of facilitating viability and resilience in the face of extreme environmental stress. Using genomic approaches, conservation management practices such as translocation, targeted gene flow, and gene-editing can now be performed with the express intention of facilitating adaptation to current and projected climate change scenarios in vulnerable species, thus reducing extinction risk and ensuring the protection of our unique biodiversity for future generations. We discuss the current barriers to implementing conservation genomic projects and the efforts being made to overcome them, including communication between researchers and managers to improve the relevance and applicability of genomic studies. We present novel approaches for facilitating adaptive capacity and accelerating natural selection in species to encourage resilience in the face of climate change.

Evolvability of Drought Response in Four Native and Non-native Conifers: Opportunities for Forest and Genetic Resource Management in Europe.

Intraspecific genetic variation in drought response is expected to play an important role in determining the persistence of tree populations in global change as it (1) allows for spontaneous selection and local adaptation of tree populations, (2) supports assisted seed transfer of less-drought-sensitive provenance, and (3) enables the integration of drought-sensitivity traits into tree breeding. Estimating the potential of such adaptation options requires quantitative genetic knowledge of drought sensitivity across significant parts of species distributions and a comparative assessment of genetic variation within economically and ecologically important tree species. We quantified genetic variation within and among populations of four conifers growing within common garden experiments in the drought-prone eastern Austria. This region experienced three strong drought periods between 1980 and 2010 that resulted in significant reductions in radial growth. Among the four tested species, Douglas-fir revealed the highest resistance during drought and silver fir the best recovery after drought, while European larch and Norway spruce showed the lowest resistance. High genetic variation among populations and phenotypic stability across all three drought events was found for Norway spruce and silver fir, but not for the other species. Heritability and evolvability of drought traits, both approximated via genetic repeatability, revealed strong differences among populations of all four species. Repeatability and evolvability for resistance were highest in Norway spruce and, for recovery, highest in European larch. Our comparison indicates that the mean drought sensitivity of a species is not related to the intraspecific genetic variation in drought response. Thus, also highly drought-sensitive species, such as Norway spruce and European larch, harbor significant genetic variation in drought response within and among populations to justify targeted tree breeding, assisted gene flow, and supportive forest management to foster local adaptations to future conditions.