Managed relocation is defined as the movement of species, populations, or genotypes to places outside the areas of their historical distributions to maintain biological diversity or ecosystem ...functioning with changing climate. It has been claimed that a major extinction event is under way and that climate change is increasing its severity. Projections indicating that climate change may drive substantial losses of biodiversity have compelled some scientists to suggest that traditional management strategies are insufficient. The managed relocation of species is a controversial management response to climate change. The published literature has emphasized biological concerns over difficult ethical, legal, and policy issues. Furthermore, ongoing managed relocation actions lack scientific and societal engagement. Our interdisciplinary team considered ethics, law, policy, ecology, and natural resources management in order to identify the key issues of managed relocation relevant for developing sound policies that support decisions for resource management. We recommend that government agencies develop and adopt best practices for managed relocation.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Mammalian spermiogenesis is a remarkable cellular transformation, during which round spermatids elongate into chromatin-condensed spermatozoa. The signaling pathways that coordinate this process are ...not well understood, and we demonstrate here that homeodomain-interacting protein kinase 4 (HIPK4) is essential for spermiogenesis and male fertility in mice. HIPK4 is predominantly expressed in round and early elongating spermatids, and
knockout males are sterile, exhibiting phenotypes consistent with oligoasthenoteratozoospermia.
mutant sperm have reduced oocyte binding and are incompetent for in vitro fertilization, but they can still produce viable offspring via intracytoplasmic sperm injection. Optical and electron microscopy of HIPK4-null male germ cells reveals defects in the filamentous actin (F-actin)-scaffolded acroplaxome during spermatid elongation and abnormal head morphologies in mature spermatozoa. We further observe that HIPK4 overexpression induces branched F-actin structures in cultured fibroblasts and that HIPK4 deficiency alters the subcellular distribution of an F-actin capping protein in the testis, supporting a role for this kinase in cytoskeleton remodeling. Our findings establish HIPK4 as an essential regulator of sperm head shaping and potential target for male contraception.
Gene transfer between species during interspecific hybridization is a widely accepted reality in plants but is considered a relatively rare phenomenon among animals. Here we describe a unique case of ...mitochondrial DNA (mtDNA) paraphyly in the skipper genus, Erynnis, that involves well-diverged allopatric species. Using molecular evidence from both mitochondrial and nuclear genomes, we found high levels of intraspecific divergence in the mitochondrial genome within E. propertius (over 4% pair-wise sequence divergence) but no such differentiation in the nuclear genome. Sequence comparisons with related Erynnis suggest that past, but recent and infrequent introgression between E. propertius and E. horatius is the most reasonable explanation for the observed pattern of mtDNA paraphyly. This example of putative introgression highlights the complexity of mtDNA evolution and suggests that similar processes could be operating in other taxa that have not been extensively sampled. Our observations reinforce the importance of involving multiple genes with different modes of inheritance in the analysis of population history of congeneric taxa.
The fossil record tells us that many species shifted their geographic distributions during historic climate changes, but this record does not portray the complete picture of future range change in ...response to climate change. In particular, it does not provide information on how species interactions will affect range shifts. Therefore, we also need modern research to generate understanding of range change. This paper focuses on the role that species interactions play in promoting or preventing geographic ranges shifts under current and future climate change, and we illustrate key points using empirical case studies from an integrated study system. Case studies can have limited generalizability, but they are critical to defining possible outcomes under climate change. Our case studies emphasize host limitation that could reduce range shifts and enemy release that could facilitate range expansion. We also need improvements in modeling that explicitly consider species interactions, and this modeling can be informed by empirical research. Finally, we discuss how species interactions have implications for range management by people.
Our failure to understand or predict evolutionary dynamics under climatic change precludes much conservation planning. Evolution may reduce extinction under global warming, but few studies have ...explored how genetic covariation, the norm for most quantitative traits, will affect the course of evolution under rapid climatic change. To draw attention to and begin to fill this gap, we draw from the population genetics literature and explore climate-driven evolution using a multi-trait model under two qualitative scenarios of climate change. Under a monotonic change in the mean environment and a change in the amplitude and frequency of a periodic environment, we show that the angle between the direction of the largest genetic covariation and the selection gradient is important in determining a population’s fitness decline, or lag load. When the environment changes monotonically in the direction of the greatest covariation, the population is able to more closely track the changing environment resulting in a lower lag load. In contrast, when the environment changes in a direction of low covariation, the ability of the population to track the changing environment is lower, and the population experiences a higher lag load. In a periodic environment, populations suffer a higher lag load under increased environmental amplitude than under increased frequency. These observations suggest that populations where the angle between the largest genetic covariation and the selection gradient is large, as well as populations experiencing an increased magnitude of environmental extremes, may be vulnerable to extinctions and genetic bottlenecks and may benefit from conservation efforts that enhance the preservation of genetic diversity. To make specific predictions of evolutionary trajectories and obtain estimates of lag loads for natural populations, climatic changes have to be quantified in terms of fitness landscapes and genetic covariation among climate-related traits must be measured. We performed an extensive review of the literature and found only 24 studies that quantify covariation in traits involving climate.
Multidimensional Evaluation of Managed Relocation Richardson, David M.; Hellmann, Jessica J.; McLachlan, Jason S. ...
Proceedings of the National Academy of Sciences - PNAS,
06/2009, Letnik:
106, Številka:
24
Journal Article
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Managed relocation (MR) has rapidly emerged as a potential intervention strategy in the toolbox of biodiversity management under climate change. Previous authors have suggested that MR (also referred ...to as assisted colonization, assisted migration, or assisted translocation) could be a last-alternative option after interrogating a linear decision tree. We argue that numerous interacting and value-laden considerations demand a more inclusive strategy for evaluating MR. The pace of modern climate change demands decision making with imperfect information, and tools that elucidate this uncertainty and integrate scientific information and social values are urgently needed. We present a heuristic tool that incorporates both ecological and social criteria in a multidimensional decision-making framework. For visualization purposes, we collapse these criteria into 4 classes that can be depicted in graphical 2-D space. This framework offers a pragmatic approach for summarizing key dimensions of MR: capturing uncertainty in the evaluation criteria, creating transparency in the evaluation process, and recognizing the inherent tradeoffs that different stakeholders bring to evaluation of MR and its alternatives.
With the growing capacity to inventory microbial community diversity, the need for statistical methods to compare community inventories is also growing. Several approaches have been proposed for ...comparing the diversity of microbial communities: some adapted from traditional ecology and others designed specifically for molecular inventories of microbes. Rarefaction is one statistical method that is commonly applied in microbial studies, and this chapter discusses the procedure and its advantages and disadvantages. Rarefaction compares observed taxon richness at a standardized sampling effort using confidence intervals. Special emphasis is placed here on the need for precise, rather than unbiased, estimation methods in microbial ecology, but precision can be judged only with a very large sample or with multiple samples drawn from a single community. With low sample sizes, rarefaction curves also have the potential to lead to incorrect rankings of relative species richness, but this chapter discusses a new method with the potential to address this problem. Finally, this chapter shows how rarefaction can be applied to the comparison of the taxonomic similarity of microbial communities.
There is a pressing need to predict how species will change their geographic ranges under climate change. Projections typically assume that temperature is a primary fitness determinant and that ...populations near the poleward (and upward) range boundary are preadapted to warming. Thus, poleward, peripheral populations will increase with warming, and these increases facilitate poleward range expansions. We tested the assumption that poleward, peripheral populations are enhanced by warming using 2 butterflies (Erynnis propertius and Papilio zelicaon) that co-occur and have contrasting degrees of host specialization and interpopulation genetic differentiation. We performed a reciprocal translocation experiment between central and poleward, peripheral populations in the field and simulated a translocation experiment that included alternate host plants. We found that the performance of both central and peripheral populations of E. propertius were enhanced during the summer months by temperatures characteristic of the range center but that local adaptation of peripheral populations to winter conditions near the range edge could counteract that enhancement. Further, poleward range expansion in this species is prevented by a lack of host plants. In P. zelicaon, the fitness of central and peripheral populations decreased under extreme summer temperatures that occurred in the field at the range center. Performance in this species also was affected by an interaction of temperature and host plant such that host species strongly mediated the fitness of peripheral individuals under differing simulated temperatures. Altogether we have evidence that facilitation of poleward range shifts through enhancement of peripheral populations is unlikely in either study species.
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