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... De-extinction dialogue represents a diversity of voices: from ethical philosophers, environmental lawyers and historians to population geneticists and biotechnologists. Peer-reviewed literature is almost evenly split between papers whose lead author is a social scientist or philosopher [20][21][22]25,65,69,70,73,74, and those whose lead author is a biological or environmental scientist [23,26,53,66,71,72,75,141,[180][181][182][183][184][185][186][187][188][189][190][191][192][193][194][195][196][197]. ...
... It is rather easy to build a body of literature based on postulation, speculation and opinion but rather difficult to build a reliable body of knowledge based on thorough reviews, model simulations and empirical data, all of which take considerable time, especially for programs that are expected to encompass entire careers or longer. Of the literature published to date, less than 10% is based upon any modelled or collected data [53,141,184,185,200] and only half root their arguments and discussions in relevant empirical or substantiated established intellectual content [19,23,25,53,65,69,71,72,74,141,155,157,[159][160][161]180,182,183,[185][186][187][188][189][190][191][192]201,202]. The remaining publications present many debates and perspectives within a "hyperbolic echo chamber" of de-extinction concerns without drawing from examples of reintroduction biology, animal welfare ethics, or other pertinent established fields of literature and science [20][21][22]69,73,154,158,[162][163][164][165][166][167][168][169][170][171][172][174][175][176][193][194][195][196][197][198], arguably inflating problematic, possibly irrelevant, or worse, unfounded points alongside important and very real critiques. ...
... It is rather easy to build a body of literature based on postulation, speculation and opinion but rather difficult to build a reliable body of knowledge based on thorough reviews, model simulations and empirical data, all of which take considerable time, especially for programs that are expected to encompass entire careers or longer. Of the literature published to date, less than 10% is based upon any modelled or collected data [53,141,184,185,200] and only half root their arguments and discussions in relevant empirical or substantiated established intellectual content [19,23,25,53,65,69,71,72,74,141,155,157,[159][160][161]180,182,183,[185][186][187][188][189][190][191][192]201,202]. The remaining publications present many debates and perspectives within a "hyperbolic echo chamber" of de-extinction concerns without drawing from examples of reintroduction biology, animal welfare ethics, or other pertinent established fields of literature and science [20][21][22]69,73,154,158,[162][163][164][165][166][167][168][169][170][171][172][174][175][176][193][194][195][196][197][198], arguably inflating problematic, possibly irrelevant, or worse, unfounded points alongside important and very real critiques. ...
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De-extinction projects for species such as the woolly mammoth and passenger pigeon have greatly stimulated public and scientific interest, producing a large body of literature and much debate. To date, there has been little consistency in descriptions of de-extinction technologies and purposes. In 2016, a special committee of the International Union for the Conservation of Nature (IUCN) published a set of guidelines for de-extinction practice, establishing the first detailed description of de-extinction; yet incoherencies in published literature persist. There are even several problems with the IUCN definition. Here I present a comprehensive definition of de-extinction practice and rationale that expounds and reconciles the biological and ecological inconsistencies in the IUCN definition. This new definition brings together the practices of reintroduction and ecological replacement with de-extinction efforts that employ breeding strategies to recover unique extinct phenotypes into a single "de-extinction" discipline. An accurate understanding of de-extinction and biotechnology segregates the restoration of certain species into a new classification of endangerment, removing them from the purview of de-extinction and into the arena of species' recovery. I term these species as "evolutionarily torpid species"; a term to apply to species falsely considered extinct, which in fact persist in the form of cryopreserved tissues and cultured cells. For the first time in published literature, all currently active de-extinction breeding programs are reviewed and their progress presented. Lastly, I review and scrutinize various topics pertaining to de-extinction in light of the growing body of peer-reviewed literature published since de-extinction breeding programs gained public attention in 2013.
... Shapiro, 2017), conservation (e.g. Peers, Thornton, Majchrzak, Bastille-Rousseau, & Murray, 2016), philosophy (e.g. Piotrowska, 2018), ethics (e.g. ...
... The potential for the former range of species to have altered significantly since the species was extirpated has been raised (Seddon, Moehrenschlager, & Ewen, 2014) and the closest to demonstrating this is the use of species distribution models to highlight that the former range of three extinct birds will be substantially reduced (Peers et al., 2016). The example of E. turgida (Hitchcock & Cowell, 2020) described above, illustrates that the former range of a species can also be heavily modified by urbanisation and fire suppression. ...
... ( Macnair 1987), and ongoing climate change ( Hof et al. 2011). Thus, in many regions of the world, conditions under which a 200-year-old tree established are likely to be quite different to those existing today ( Sgró, Lowe & Hoffmann 2011), and the ecological context of a species that went extinct even only 100 years ago, such as the passenger pigeon (Ectopistes migratorius), has changed dramatically ( Sherkow & Greely 2013;Peers et al. 2016). ...
... profound, unintended eco-evolutionary changes in the local system (including hysteretic phenomena, in which irreversible catastrophic shift occurs, see e.g., van Nes & Scheffer 2004), (2) unintended spread of the species, which is likely in the case of mismatch between historic and current or future habitat suitability ( Peers et al. 2016), (3) sudden changes in local human pressures (e.g., increase of tourism following the resurrection of a highly charismatic species). These ecological costs, which are similar to some of the well-known ...
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De-extinction, the process of resurrecting extinct species, is in an early stage of scientific implementation. However, its potential to contribute effectively to biodiversity conservation remains unexplored, especially from an evolutionary perspective. 2.We review and discuss the application of the existing evolutionary conservation framework to potential de-extinction projects. We aim to understand how evolutionary processes can influence the dynamics of resurrected populations, and to place de-extinction within micro- and macro-evolutionary conservation perspectives. 3.In programs aiming to revive long-extinct species, the most important constraints to the short-term viability of any resurrected population are (1) their intrinsically low evolutionary resilience, and (2) their poor eco-evolutionary experience, in relation to the absence of (co)adaption to biotic and abiotic changes in the recipient environment. 4.Assuming that some populations of resurrected species can persist locally, they have the potential to bring substantial benefits to biodiversity if the time since initial extinction is short relative to evolutionary dynamics. The restoration of lost genetic information could lead, along with the re-instatement of lost ecological functions, to the restoration of some evolutionary patrimony and processes, such as adaptation and diversification. 5.However, substantial evolutionary costs might occur, including unintended eco-evolutionary changes in the local system, and unintended spread of the species. Further, evolutionary benefits are limited because (1) the use of resurrected populations as « evolutionary proxies » of extinct species is meaningless; (2) their phylogenetic originality is likely to be limited by the selection of inappropriate candidate species, and the fact that the original species might be those for which de-extinction is the most difficult to achieve practically; (3) the resurrection of a few extinct species does not have the potential to conserve as much evolutionary history as traditional conservation strategies, such as the reduction of ongoing species declines and extinction debts. 6.De-extinction is a stimulating idea, which is not intrinsically antagonistic to the conservation of evolutionary processes. However, poor choice of candidate species, and most importantly, too long time scales between a species’ extinction and its resurrection are associated with low expected evolutionary benefits and likely unacceptable eco-evolutionary risks. This article is protected by copyright. All rights reserved.
... Some conservationists will advocate for such proxy species to be reintroduced to a suitable former geographic environment (Seddon et al. 2014b), and perceived ecosystem management benefits may arise from doing so (Church 2013). Environmental differences between contemporary and historic habitats (Peers et al. 2016) might encourage further genetic manipulation to create better adapted species. Depending on the length of time the proxy species has been extinct and the method used to produce the proxy, introducing such entities to the wild is tantamount to introducing a non-native species (IUCN 2013; IUCN/SSC 2016; Genovesi and Simberloff 2020), an action that in the absence of predictive knowledge increases the likelihood of unintended ecological consequences. ...
... Some conservationists will advocate for such proxy species to be reintroduced to a suitable former geographic environment (Seddon et al. 2014b), and perceived ecosystem management benefits may arise from doing so (Church 2013). Environmental differences between contemporary and historic habitats (Peers et al. 2016) might encourage further genetic manipulation to create better adapted species. Depending on the length of time the proxy species has been extinct and the method used to produce the proxy, introducing such entities to the wild is tantamount to introducing a non-native species (IUCN 2013; IUCN/SSC 2016; Genovesi and Simberloff 2020), an action that in the absence of predictive knowledge increases the likelihood of unintended ecological consequences. ...
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Unprecedented rates of introduction and spread of non-native species pose burgeoning challenges to biodiversity, natural resource management, regional economies, and human health. Current biosecurity efforts are failing to keep pace with globalization, revealing critical gaps in our understanding and response to invasions. Here, we identify four priority areas to advance invasion science in the face of rapid global environmental change. First, invasion science should strive to develop a more comprehensive framework for predicting how the behavior, abundance, and interspecific interactions of non-native species vary in relation to conditions in receiving environments and how these factors govern the ecological impacts of invasion. A second priority is to understand the potential synergistic effects of multiple co-occurring stressors – particularly involving climate change – on the establishment and impact of non-native species. Climate adaptation and mitigation strategies will need to consider the possible consequences of promoting non-native species, and appropriate management responses to non-native species will need to be developed. The third priority is to address the taxonomic impediment. The ability to detect and evaluate invasion risks is compromised by a growing deficit in taxonomic expertise, which cannot be adequately compensated by new molecular technologies alone. Management of biosecurity risks will become increasingly challenging unless academia, industry, and governments train and employ new personnel in taxonomy and systematics. Fourth, we recommend that internationally cooperative biosecurity strategies consider the bridgehead effects of global dispersal networks, in which organisms tend to invade new regions from locations where they have already established. Cooperation among countries to eradicate or control species established in bridgehead regions should yield greater benefit than independent attempts by individual countries to exclude these species from arriving and establishing.
... And what could be the evolutionary costs, assuming that the resurrected population is viable? Most, if not all evolutionary costs are probably mediated by ecological costs: (i) profound, unintended eco-evolutionary changes in the local system (including hysteretic phenomena, in which irreversible catastrophic shift occurs, see, for example Van Nes & Scheffer 2004), (ii) unintended spread of the species, which is likely in the case of mismatch between historic and current or future habitat suitability (Peers et al. 2016), (iii) sudden changes in local human pressures (e.g. increase of tourism following the resurrection of a highly charismatic species). These ecological costs, which are similar to some of the well-known consequences of invasive species and local environmental degradation, can have major unintended evolutionary consequences (Hendry et al. 2010). ...
Thesis
The impact of human activities on biological diversity is intensifying, and many studies suggest that we are entering a sixth mass extinction. Among the possible actions to halt the erosion of biodiversity, the human-mediated movements of organisms for conservation purposes, i.e. "conservation translocations", are increasingly used to restore populations. In particular, reintroductions aim to restore a viable population of a species within its indigenous range, following local population extinction. These actions often address local or national conservation needs, and their contribution to large-scale biodiversity conservation has yet to be determined. This thesis focuses on the coherence of reintroduction efforts at large scale, by questioning three aspects. The first aspect focuses on a retrospective inventory of bird and mammal reintroduction efforts in order to question the evolutionary and functional representativeness and originality of reintroduction targets. The second aspect focuses on the effectiveness of these programs. We propose a conceptual and unifying demographic framework to define success criteria for conservation translocation programs. Finally, in a final section, we explore the potential benefits of de-extinction projects by questioning their ability to restore evolutionary processes.
... This analysis also served to assess if and where permanently protected areas existed that possessed suitable habitat for chestnut. Other studies have similarly assessed potential overlap between protected lands and the geographic range of candidate species for de-extinction (Peers et al., 2016). ...
Article
American chestnut (Castanea dentata) once held great economic and ecological importance in eastern US forests before its demise due to an invasive blight fungus. Backcross breeding and genetic engineering methods are currently developing a blight-resistant tree with mostly American chestnut traits. With the potential re-introduction of chestnut, research has sought to understand the geographic distribution of chestnut to locate potential restoration sites, but less research has compared ideal restoration sites to underlying land ownership. This research models the historical distribution of chestnut in western New York State (NYS, approximately 27,617 km 2), containing a portion of the original range of chestnut, in order to determine suitable areas for chestnut reintroduction. This study models chestnut distribution using original land survey record (OLSR) data (ca. 1797-1799 CE) and species distribution models (SDMs), then compares model predictions to current protected lands. Results indicate that depending upon modeling technique, predicted suitable habitat for chestnut ranges 27.9-49.7% of the study area, and that 8.0-11.5% of suitable area is within protected land parcels. SDMs suggest that within the study area, the two predictors most important to chestnut distribution are soil pH and terrain slope, with chestnut favoring acidic soils and steeper slopes. By identifying sites for potential re-introduction of chestnut, this study highlights that reintroduction will depend upon cooperation of private landowners along with governments and non-governmental agencies. This study offers a revision to the historical distribution of chestnut in western NYS, and provides insight into land ownership and management issues facing its restoration.
... The International Union for the Conservation of Nature (IUCN) (2013) suggests the use of species distribution models (SDMs) to understand the climate requirements of all species targeted for reintroduction or translocation and to project the availability of climatically suitable habitat for those species now and in the future. SDMs have been used extensively in biodiversity conservation for a variety of applications (Franklin 2013;Rodríguez et al. 2007), including forecasting the natural movement of species in response to climate change (Bosso et al. 2017a, b;Fitzpatrick et al. 2008;Thomas et al. 2004;Williams and Blois 2018;Zhang et al. 2017); predicting the spread of invasive species (Bosso et al. 2017a, b;Katz and Zellmer 2018;Mainali et al. 2015;Petitpierre et al. 2017); identifying appropriate sites for reintroduction within native ranges (Adhikari et al. 2012;McDonald et al. 2018;Pearce and Lindenmayer 1998;Swinnen et al. 2017); planning for the conservation of rare or threatened species (Kabir et al. 2017;Spiers et al. 2018;Vitt et al. 2010;Webb et al. 2017;Yang et al. 2013); and anticipating the resurrection of extinct ones (Peers et al. 2016). These various applications demonstrate the utility of SDMs as foresight tool; they can be used to expand the timescale of conservation planning, particularly in a context of environmental uncertainty and technological novelty. ...
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Given the scale and speed of contemporary environmental changes, intensive conservation interventions are increasingly being proposed that would assist the evolution of adaptive traits in threatened species. The ambition of these projects is tempered by a number of concerns, including the potential maladaptation of manipulated organisms for contemporary and future climatic conditions in their historical ranges. Following the guidelines of the International Union for the Conservation of Nature, we use a species distribution model (SDM) to consider the potential impact of climate change on the distribution and quantity of suitable habitat for American chestnut (Castanea dentata), a functionally extinct forest species that has been the focus of various restoration efforts for over 100 years. Consistent with other SDMs for North American trees, our model shows contraction of climatically suitable habitat for American chestnut within the species’ historical range and the expansion of climatically suitable habitat in regions to the north of it by 2080. These broad changes have significant implications for restoration practice. In particular, they highlight the importance of germplasm conservation, local adaptation, and addressing knowledge gaps about the interspecific interactions of American chestnut. More generally, this model demonstrates that the goals of assisted evolution projects, which often aim to maintain species in their native ranges, need to account for the uncertainty and novelty of future environmental conditions.
... So far, much attention has focused on selecting species that are good candidates for de-extinction (Seddon et al., 2014) and on the development of techniques required to bring back an extinct species (Church & Regis, 2012). While initial research on evaluating habitat suitability for potential de-extinction projects has just begun (e.g., Peers et al., 2016), the best possible knowledge of the inhabited environment, realized niche, and autecology of any candidate species will be required to successfully reintroduce populations into the wild (Seddon et al., 2014), as well as fully evaluate present and future habitat suitability. ...
Article
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The study of the ecology and natural history of species has traditionally ceased when a species goes extinct, despite the benefit to current and future generations of potential findings. We used the extinct Carolina parakeet as a case study to develop a framework investigating the distributional limits, subspecific variation, and migratory habits of this species as a means to recover important information about recently extinct species. We united historical accounts with museum collections to develop an exhaustive , comprehensive database of every known occurrence of this once iconic species. With these data, we combined species distribution models and ordinal niche comparisons to confront multiple conjectured hypotheses about the parakeet's ecology with empirical data on where and when this species occurred. Our results demonstrate that the Carolina parakeet's range was likely much smaller than previously believed, that the eastern and western subspecies occupied different climatic niches with broad geographical separation, and that the western subspecies was likely a seasonal migrant while the eastern subspecies was not. This study highlights the novelty and importance of collecting occurrence data from published observations on extinct species, providing a starting point for future investigations of the factors that drove the Carolina parakeet to extinction. Moreover, the recovery of lost autecological knowledge could benefit the conservation of other parrot species currently in decline and would be crucial to the success of potential de-extinction efforts for the Carolina parakeet.
... Arguments in favour of de-extinction include necessity, driven by the rapid rate of species and habitat loss 3,4 , an ethical duty to redress past mistakes 5 , as well as potential technological and ecological knowledge that could stem from de-extinction programmes 4 . Counter-arguments include high risk of failure due to difficulties of cloning for some species 6 , technical risks inherent in re-introductions [7][8][9] , loss of culture in resurrected animal species 8 , and lack of remaining habitat for some species 10,11 , as well as negative consequences for extant species, including reduced incentive for traditional conservation 12 , and ecological impacts of introducing long-absent or genetically modified species 12 . ...
Article
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There is contentious debate surrounding the merits of de-extinction as a biodiversity conservation tool. Here, we use extant analogues to predict conservation actions for potential de-extinction candidate species from New Zealand and the Australian state of New South Wales, and use a prioritization protocol to predict the impacts of reintroducing and maintaining populations of these species on conservation of extant threatened species. Even using the optimistic assumptions that resurrection of species is externally sponsored, and that actions for resurrected species can share costs with extant analogue species, public funding for conservation of resurrected species would lead to fewer extant species that could be conserved, suggesting net biodiversity loss. If full costs of establishment and maintenance for resurrected species populations were publicly funded, there could be substantial sacrifices in extant species conservation. If conservation of resurrected species populations could be fully externally sponsored, there could be benefits to extant threatened species. However, such benefits would be outweighed by opportunity costs, assuming such discretionary money could directly fund conservation of extant species. Potential sacrifices in conservation of extant species should be a crucial consideration in deciding whether to invest in de-extinction or focus our efforts on extant species.
... populations with relatively low evolutionary potential). Despite strong evidence that extinction risk increases as genetic diversity decreases (Frankham, Ballou & Briscoe 2010;Allendorf, Luikart & Aitken 2012), the conservation genetic implications of de-extinction have received surprisingly little coverage in the peer-reviewed literature (Gar cia-Gonz alez &Margalida 2014;Peers et al. 2016), excluding the promise of using genome-editing technologies to enhance conservation outcomes for extant threatened species (Hellmann & Pfrender 2011;Shapiro 2015;Johnson et al. 2016;Taylor & Gemmell 2016;Piaggio et al. 2017). Here, we argue if the end goal of de-extinction is to create self-sustaining populations of functional proxies to restore ecological function, then due consideration should be given to the creation of adequately large, genetically diverse populations that possess the ability to adapt to a changing environment (i.e. ...
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De-extinction sensu stricto is the resurrection of phenotypic traits once possessed by extinct species to create extant functional proxies. To realise the ecological benefit of de-extinction, self-sustaining (genetically viable) populations of functional proxies are required. It is often implied, yet rarely stated, that the genetic challenges associated with the survival and recovery of extant threatened species in an effort to conserve biodiversity are also relevant to the use of functional proxies of extinct species as a conversation tool. Here, we highlight the importance of prioritising evolutionary potential − the capacity to evolve (adapt) in response to environmental change − in populations of functional proxies. We use conservation genetic principles to describe impediments to the creation and maintenance of evolutionary potential as a series of potentially unavoidable genetic bottlenecks (pre-extinction, resurrection, captive, translocation). To give any successfully translocated populations of functional proxies the best chance to survive beyond the first few generations in the wild, we advocate the use of a holistic framework that includes the creation of sufficiently large, genetically diverse popluations that harbour the ability to adapt to a changing environment. This article is protected by copyright. All rights reserved.
... Shortstopping can benefit migrants by decreasing the amount of energy they spend on long-distance flight 7 and facilitating earlier arrival on the breeding grounds 8 , but these benefits require finding suitable new wintering sites closer to the breeding grounds. Changes in climate and land use can create suitable new sites, where warmer temperatures decrease energy expenditure when overwintering at higher latitudes 7,9,10 and increased food availability from land use change (for example, land conversion to agriculture) can further offset the increased energetic requirements of overwintering in a colder place 4,11,12 . ...
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Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.
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We provide an overview of the use of species distribution modeling to address research questions related to parrot ecology and conservation at a global scale. We conducted a literature search and applied filters to select the 82 most relevant studies to discuss. The study of parrot species distribution has increased steadily in the past 30 years, with methods and computing development maturing and facilitating their application for a wide range of research and applied questions. Conservation topics was the most popular topic (37%), followed by ecology (34%) and invasion ecology (20%). The role of abiotic factors explaining parrot distribution is the most frequent ecological application. The high prevalence of studies supporting on-ground conservation problems is a remarkable example of reduction in the research-action gap. Prediction of invasion risk and assessment of invasion effect were more prevalent than examples evaluating the environmental or economic impact of these invasions. The integration of species distribution models with other tools in the decision-making process and other data (e.g., landscape metrics, genetic, behavior) could even further expand the range of applications and provide a more nuanced understanding of how parrot species are responding to their even more changing landscape and threats.
Article
Ancient DNA (aDNA) analysis has led to significant breakthroughs in our understanding of the origin of our own species as well as that of many commensal and wild species. New approaches in aDNA research promise to make it a major tool for adaptation to and mitigation of the impacts of the rapidly changing climates of the Anthropocene. This article reviews a number of these new lines of research and their current and potential future contributions to responding to climate change, particularly in two areas: the generation of deeper baseline data on ecological and environmental change, and the tracking and recovery of lost genetic diversity to strengthen the resilience of living species. The article argues that aDNA analysis is creating a powerful new pathway for archeology to engage with the challenges of the Anthropocene.
Article
Scientists around the world are actively working toward de-extinction, the concept of bringing extinct species back to life. Before herds of woolly mammoths roam and flocks of passenger pigeons soar once again, the international community needs to consider what should be done about de-extinct species from a legal and policy perspective. In the context of international environmental law, the precautionary principle counsels that the absence of scientific certainty should not be used as an excuse for failing to prevent environmental harm. No global legal framework exists to protect and regulate de-extinct species, and this Article seeks to fill that gap by anticipating how the global legal framework for de-extinction could be structured. The Article recommends that the notions underlying the precautionary principle should be applied to de-extinction and that the role of international treaties and other international agreements should be considered to determine how they will or should apply to de-extinct species. The Article explains the concepts of extinction and de-extinction, reviews relevant international treaties and agreements, and analyzes how those treaties and agreements might affect de-extinct species as objects of trade, as migratory species, as biodiversity, as genetically modified organisms, and as intellectual property. The Article provides suggestions about how the treaties and the international legal framework could be modified to address de-extinct species more directly. Regardless of ongoing moral and ethical debates about de-extinction, the Article concludes that the international community must begin to contemplate how de-extinct species will be regulated and protected under existing and prospective international laws and policies.
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Because habitat loss is the main cause of extinction, where and how much society chooses to protect is vital for saving species. The United States is well positioned economically and politically to pursue habitat conservation should it be a societal goal. We assessed the US protected area portfolio with respect to biodiversity in the country. New synthesis maps for terrestrial vertebrates, freshwater fish, and trees permit comparison with protected areas to identify priorities for future conservation investment. Although the total area protected is substantial, its geographic configuration is nearly the opposite of patterns of endemism within the country. Most protected lands are in the West, whereas the vulnerable species are largely in the Southeast. Private land protections are significant, but they are not concentrated where the priorities are. To adequately protect the nation’s unique biodiversity, we recommend specific areas deserving additional protection, some of them including public lands, but many others requiring private investment.
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Invasive alien species can have serious adverse impacts on both the environment and the economy. Being able to predict the impacts of an alien species could assist in preventing or reducing these impacts. This study aimed to establish whether there are any life history traits consistently correlated with the impacts of alien birds across two continents, Europe and Australia, as a first step toward identifying life history traits that may have the potential to be adopted as predictors of alien bird impacts. A recently established impact scoring system was used in combination with a literature review to allocate impact scores to alien bird species with self-sustaining populations in Australia. These scores were then tested for correlation with a series of life history traits. The results were compared to data from a previous study in Europe, undertaken using the same methodology, in order to establish whether there are any life history traits consistently correlated with impact across both continents. Habitat generalism was the only life history trait found to be consistently correlated with impact in both Europe and Australia. This trait shows promise as a potential predictor of alien bird impacts. The results support the findings of previous studies in this field, and could be used to inform decisions regarding the prevention and management of future invasions.
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Reviving extinct species with new synthetic biology tools is as exciting an idea as it is controversial. Genomic manipulation of extinct species’ close relatives and/or cloning suitably preserved cells are the two main ways synthetic biology could be used to revive species. Discussions of where to target initial revival efforts have focused on species’ charisma (e.g. Woolly mammoth, Passenger pigeon) with less emphasis on feasibility or the ecological, ethical and legal considerations. Here I discuss who we could and should de-extinct, focussing on these latter criteria. Given the current devastating anthropogenic pressures on biodiversity, I suggest that a better use of de-extinction technologies would be to focus them on preventing species extinctions by restoring populations of critically endangered species. For example, this could be through increasing population numbers through cloning or genomic manipulation to better enable susceptible species to adapt to global change or by restoring genetic diversity by reviving extinct sub-species (e.g. Quagga, Barbary lion). This idea circumvents many of the criticisms of de-extinction from conservationists, whilst retaining public interest in de-extinction.
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Technological advances have raised the controversial prospect of resurrecting extinct species. Species DeExtinction should involve more than the production of biological orphans to be scrutinized in the laboratory or zoo. If DeExtinction is to realize its stated goals of deep ecological enrichment, then resurrected animals must be translocated (i.e., released within suitable habitat). Therefore, DeExtinction is a conservation translocation issue and the selection of potential DeExtinction candidates must consider the feasibility and risks associated with reintroduction. The International Union for the Conservation of Nature (IUCN) Guidelines on Reintroductions and Other Conservation Translocations provide a framework for DeExtinction candidate selection. We translate these Guidelines into ten questions to be addressed early on in the selection process to eliminate unsuitable reintroduction candidates. We apply these questions to the thylacine, Yangtze River Dolphin, and Xerces blue butterfly.
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The ecological impacts of marine invasive species vary according to the spatial and temporal scale of analysis, thereby challenging the extraction of generalities about underlying mechanisms. Here, we applied a broad impact framework that addresses this scale-dependency, to test if general drivers of impacts can be identified and quantified from marine invasion experiments. This framework explains variability in impacts according to the unique (specific) and universal (general) attributes of the (1) invasive organism, (2) resident biota, (3) resource levels, and (4) abiotic conditions. In this framework, unique and universal attributes encompass the properties that are either ecologically relevant to only a few specific invasions (e.g. a unique toxin) or to most invasions (e.g. invader density, size, age or longevity), respectively. We reviewed 88 published marine invasion impact experiments, where 18 tested for effects of universal and 11 for unique attributes of the invasive organism (63 tested for presence–absence effects, where these attributes are confounded). A meta-analysis confirmed that the species identity and density (representing a unique and universal attribute, respectively) of the invader significantly predicted impacts. These attributes should, therefore, whenever possible, be treated as separate impact-modifiers. By contrast, very few experiments have tested if universal or unique attributes of the resident biota, the resource levels or the abiotic conditions modify invasion impact. This highlights a major research gap; quantitative syntheses cannot be undertaken until more factorial experiments have manipulated the invasive species and habitat-associated drivers in concert (with ≥2 treatments per test factor). In conclusion, to facilitate a broader understanding of marine invasion impacts, we advocate that universal and unique impact-components, whenever possible, are treated as separate test entities that should be examined for each of the four impact drivers.
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A predictive understanding of the ecological impacts of nonnative species has been slow to develop, owing largely to an apparent dearth of clearly defined hypotheses and the lack of a broad theoretical framework. The context dependency of impact has fueled the perception that meaningful generalizations are nonexistent. Here, we identified and reviewed 19 testable hypotheses that explain temporal and spatial variation in impact. Despite poor validation of most hypotheses to date, evidence suggests that each can explain at least some impacts in some situations. Several hypotheses are broad in scope (applying to plants and animals in virtually all contexts) and some of them, intriguingly, link processes of colonization and impact. Collectively, these hypotheses highlight the importance of the functional ecology of the nonnative species and the structure, diversity, and evolutionary experience of the recipient community as general determinants of impact; thus, they could provide the foundation for a theoretical framework for understanding and predicting impact. Further substantive progress toward this goal requires explicit consideration of within-taxon and across-taxa variation in the per capita effect of invaders, and analyses of complex interactions between invaders and their biotic and abiotic environments.
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The benefits of protected areas (PAs) for biodiversity have been questioned in the context of climate change because PAs are static, whereas the distributions of species are dynamic. Current PAs may, however, continue to be important if they provide suitable locations for species to colonize at their leading-edge range boundaries, thereby enabling spread into new regions. Here, we present an empirical assessment of the role of PAs as targets for colonization during recent range expansions. Records from intensive surveys revealed that seven bird and butterfly species have colonized PAs 4.2 (median) times more frequently than expected from the availability of PAs in the landscapes colonized. Records of an additional 256 invertebrate species with less-intensive surveys supported these findings and showed that 98% of species are disproportionately associated with PAs in newly colonized parts of their ranges. Although colonizing species favor PAs in general, species vary greatly in their reliance on PAs, reflecting differences in the dependence of individual species on particular habitats and other conditions that are available only in PAs. These findings highlight the importance of current PAs for facilitating range expansions and show that a small subset of the landscape receives a high proportion of colonizations by range-expanding species.
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Aim This paper presents a tool for long-term global change studies; it is an update of the History Database of the Global Environment (HYDE) with estimates of some of the underlying demographic and agricultural driving factors. Methods Historical population, cropland and pasture statistics are combined with satellite information and specific allocation algorithms (which change over time) to create spatially explicit maps, which are fully consistent on a 5′ longitude/latitude grid resolution, and cover the period 10,000 bc to ad 2000. Results Cropland occupied roughly less than 1% of the global ice-free land area for a long time until ad 1000, similar to the area used for pasture. In the centuries that followed, the share of global cropland increased to 2% in ad 1700 (c. 3 million km2) and 11% in ad 2000 (15 million km2), while the share of pasture area grew from 2% in ad 1700 to 24% in ad 2000 (34 million km2) These profound land-use changes have had, and will continue to have, quite considerable consequences for global biogeochemical cycles, and subsequently global climate change. Main conclusions Some researchers suggest that humans have shifted from living in the Holocene (emergence of agriculture) into the Anthropocene (humans capable of changing the Earth's atmosphere) since the start of the Industrial Revolution. But in the light of the sheer size and magnitude of some historical land-use changes (e.g. as result of the depopulation of Europe due to the Black Death in the 14th century and the aftermath of the colonization of the Americas in the 16th century) we believe that this point might have occurred earlier in time. While there are still many uncertainties and gaps in our knowledge about the importance of land use (change) in the global biogeochemical cycle, we hope that this database can help global (climate) change modellers to close parts of this gap.
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Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km(2) to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally, these data should be sampled to reflect variation in the underlying environment across large spatial extents, and at fine spatial resolution. Simplified ecosystems where there are relatively few interacting species and sometimes a wealth of existing ecosystem monitoring data (e.g. arctic, alpine or island habitats) offer settings where the development of modelling tools that account for biotic interactions may be less difficult than elsewhere.
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The distributions of many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate. Using a meta-analysis, we estimated that the distributions of species have recently shifted to higher elevations at a median rate of 11.0 meters per decade, and to higher latitudes at a median rate of 16.9 kilometers per decade. These rates are approximately two and three times faster than previously reported. The distances moved by species are greatest in studies showing the highest levels of warming, with average latitudinal shifts being generally sufficient to track temperature changes. However, individual species vary greatly in their rates of change, suggesting that the range shift of each species depends on multiple internal species traits and external drivers of change. Rapid average shifts derive from a wide diversity of responses by individual species.
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Background: Significant shifts in climate are considered a threat to plants and animals with significant physiological limitations and limited dispersal abilities. The southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Plethodontids are lungless ectotherms, so their ecology is strongly governed by temperature and precipitation. Many plethodontid species in southern Appalachia exist in high elevation habitats that may be at or near their thermal maxima, and may also have limited dispersal abilities across warmer valley bottoms. Methodology/principal findings: We used a maximum-entropy approach (program Maxent) to model the suitable climatic habitat of 41 plethodontid salamander species inhabiting the Appalachian Highlands region (33 individual species and eight species included within two species complexes). We evaluated the relative change in suitable climatic habitat for these species in the Appalachian Highlands from the current climate to the years 2020, 2050, and 2080, using both the HADCM3 and the CGCM3 models, each under low and high CO(2) scenarios, and using two-model thresholds levels (relative suitability thresholds for determining suitable/unsuitable range), for a total of 8 scenarios per species. Conclusion/significance: While models differed slightly, every scenario projected significant declines in suitable habitat within the Appalachian Highlands as early as 2020. Species with more southern ranges and with smaller ranges had larger projected habitat loss. Despite significant differences in projected precipitation changes to the region, projections did not differ significantly between global circulation models. CO(2) emissions scenario and model threshold had small effects on projected habitat loss by 2020, but did not affect longer-term projections. Results of this study indicate that choice of model threshold and CO(2) emissions scenario affect short-term projected shifts in climatic distributions of species; however, these factors and choice of global circulation model have relatively small affects on what is significant projected loss of habitat for many salamander species that currently occupy the Appalachian Highlands.
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Species distribution models (SDMs) are common tools for assessing the potential impact of climate change on species ranges. Uncertainty in SDM output occurs due to differences among alternate models, species characteristics and scenarios of future climate. While considerable effort is being devoted to identifying and quantifying the first two sources of variation, a greater understanding of climate scenarios and how they affect SDM output is also needed. Climate models are complex tools: variability occurs among alternate simulations, and no single 'best' model exists. The selection of climate scenarios for impacts assessments should not be undertaken arbitrarily - strengths and weakness of different climate models should be considered. In this paper, we provide bioclimatic modellers with an overview of emissions scenarios and climate models, discuss uncertainty surrounding projections of future climate and suggest steps that can be taken to reduce and communicate climate scenario-related uncertainty in assessments of future species responses to climate change.
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Causal attribution of recent biological trends to climate change is complicated because non-climatic influences dominate local, short-term biological changes. Any underlying signal from climate change is likely to be revealed by analyses that seek systematic trends across diverse species and geographic regions; however, debates within the Intergovernmental Panel on Climate Change (IPCC) reveal several definitions of a 'systematic trend'. Here, we explore these differences, apply diverse analyses to more than 1,700 species, and show that recent biological trends match climate change predictions. Global meta-analyses documented significant range shifts averaging 6.1 km per decade towards the poles (or metres per decade upward), and significant mean advancement of spring events by 2.3 days per decade. We define a diagnostic fingerprint of temporal and spatial 'sign-switching' responses uniquely predicted by twentieth century climate trends. Among appropriate long-term/large-scale/multi-species data sets, this diagnostic fingerprint was found for 279 species. This suite of analyses generates 'very high confidence' (as laid down by the IPCC) that climate change is already affecting living systems.
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Species' invasions have long been regarded as enormously complex processes, so complex as to defy predictivity. Phases of this process, however, are emerging as highly predictable: the potential geographic course of an invasion can be anticipated with high precision based on the ecological niche characteristics of a species in its native geographic distributional area. This predictivity depends on the premise that ecological niches constitute long-term stable constraints on the potential geographic distributions of species, for which a sizeable body of evidence is accumulating. Hence, although the entire invasion process is indeed complex, the geographic course that invasions are able to take can be anticipated with considerable confidence.
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CO2 emissions from fossil-fuel burning and industrial processes have been accelerating at a global scale, with their growth rate increasing from 1.1% y(-1) for 1990-1999 to >3% y(-1) for 2000-2004. The emissions growth rate since 2000 was greater than for the most fossil-fuel intensive of the Intergovernmental Panel on Climate Change emissions scenarios developed in the late 1990s. Global emissions growth since 2000 was driven by a cessation or reversal of earlier declining trends in the energy intensity of gross domestic product (GDP) (energy/GDP) and the carbon intensity of energy (emissions/energy), coupled with continuing increases in population and per-capita GDP. Nearly constant or slightly increasing trends in the carbon intensity of energy have been recently observed in both developed and developing regions. No region is decarbonizing its energy supply. The growth rate in emissions is strongest in rapidly developing economies, particularly China. Together, the developing and least-developed economies (forming 80% of the world's population) accounted for 73% of global emissions growth in 2004 but only 41% of global emissions and only 23% of global cumulative emissions since the mid-18th century. The results have implications for global equity.
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Reintroductions are attempts to return species to parts of their historical ranges where they were extirpated, and might involve release of either captive-bred or wild-caught individuals. The poor success rate of reintroductions worldwide has led to frequent calls for greater monitoring, and since 1990 there has been an exponential increase in the number of peer-reviewed publications related to reintroduction. However, these publications have largely been descriptive accounts or have addressed questions retrospectively based on the available data. Here, we advocate a more strategic approach where research and monitoring targets questions that are identified a priori. We propose ten key questions for reintroduction biology, with different questions focusing at the population, metapopulation and ecosystem level. We explain the conceptual framework behind each question, provide suggestions for the best methods to address them, and identify links with the related disciplines of restoration ecology and invasion biology. We conclude by showing how the framework of questions can be used to encourage a more integrated approach to reintroduction biology.
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The United States Environmental Protection Agency's Community Multiscale Air Quality (CMAQ) regional-scale model is used to study concentrations and dry deposition of nitrogen species in North Carolina (NC) during the summer season. Each modelled and measured species featured a similar diurnal trend. A process budget analysis (production and removal evaluation) of NO, NO 2 , and NO Y depicted the model's capability to evaluate various process contributions. Dry deposition of NH 3 contributed 34.2 ± 57.9 µg N m -2 hr -1 ; whereas HNO 3 contributed slightly larger dry deposition of nitrogen, 35.2 ± 16.0 µg N m -2 hr -1 , in NC. NH 4 + and NO 3 - hourly-averaged wet deposition fluxes were calculated as 37.3 ± 19.7 µg N -2 hr -1 and 40.6 ± 11.8 µg N m -2 hr -1 , respectively. Examination of total nitrogen deposition during the summer season in NC found that NH 3 contributes approximately 50% of the dry deposition and NO 3 - contributes approximately 50% of the wet deposition.
Article
Taxonomic bias has been documented in general science and conservation research publications. We examined whether taxonomic bias is similarly severe in actual conservation programmes as indicated by the focus of species reintroduction projects worldwide. We compiled a database of reintroduction projects worldwide, yielding a total of 699 species of plants and animals that are the focus of recent, current or planned reintroductions. Using IUCN (World Conservation Union) data for total numbers of known species worldwide, we found that vertebrate projects were over-represented with respect to their prevalence in nature. Within vertebrates, mammals and, to a lesser extent, birds, were over-represented, whereas fish were under-represented. This over-representation extended to two mammal orders, artiodactylids and carnivores, and to four bird orders, anseriforms, falconiforms, gruiforms and galliforms. For neither mammals nor birds was reintroduction project bias related to any differences between orders in vulnerability to threat. Bird species that are the focus of reintroduction efforts are more likely to be categorised as ‘Threatened’ than expected on the basis of the distribution of all known species over all threat categories, however, nearly half of all bird species being reintroduced are classified as ‘Least Concern’. The selection of candidates for reintroduction programmes is likely to consider national priorities, availability of funding and local community support, over global conservation status, While a focus on charismatic species may serve to garner public support for conservation efforts, it may also divert scarce conservation resources away from taxa more in need of attention.
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We are entering an age in which species extinction may be reversible. De-extinction, as it has been labeled, can apply to any species for which DNA can be recovered, from woolly mammoths of the Pleistocene to thylacines and passenger pigeons from the twentieth century. These developments, which were showcased in March 2013 at a daylong conference called TEDxDeExtinction, held in Washington, DC, (http:// tedxdeextinction.org), are exciting to some scientists and terrifying to others. If we are to embark on this de-extinction journey, an act some might label playing God, we need to establish the rules of the game. I want to suggest that the well-established standards for species reintroduction projects provide a solid foundation on which de-extinction can be built. Critics of de-extinction in the popular science media have quickly pointed out drawbacks. From an ethical perspective, they have pointed to potential violations of animal welfare standards, the potential drain on resources that could be used in the conservation of still-existing species, and the implication that species destruction might be seen as permissible if it is reversible. The ecological objections have included the lack of ecosystems in which the re-created creatures could live, the potential invasiveness of the species in the ecosystem, and the potential for new disease vectors. Exploration of de-extinction’s ethical dilemmas will require serious scientific and public debate, including a significant contribution from humanities researchers, including philosophers and historians, who have the appropriate theoretical background for conceptualizing what is at stake. I will not tackle those ethical issues here. The solution to the ecological dilemmas, however, may already be at hand through the application of reintroduction standards. Reintroduction as a guide Reintroduction, the release of a species into an area in which it had been indigenous but has since become extinct, is a long-standing practice. The earliest use of the word reintroduction in a conservation context is in an article from 1832 about the return of capercaillie (or capercailzie) to Scotland (Wilson 1832). The western capercaillie was hunted out in Scotland in the late eighteenth century, and Wilson reported on the first attempt to bring the birds back to Scotland using specimens from Sweden. From these humble beginnings, an entire science of reintroduction has been built up, particularly over the last 30 years. Reintroduction science has a strong institutional basis in the International Union for Conservation of Nature (IUCN) and in its Species Survival Commission reintroduction specialist group, founded in 1988. The IUCN developed guidelines for reintroduction (IUCN 1998), which are currently under revision (Dalrymple and Moehrenschlager 2013). The guidelines suggest background studies to allow identification of the species’ habitat requirements, identification of lessons learned from prior reintroduction projects of similar species, evaluation of potential sites within the former range of the species, selection of appropriately diverse genetic stock, and an assessment of the socioeconomic context of the project. Armstrong and Seddon (2008) extended the guidelines, proposing key questions at the population, metapopulation, and ecosystem levels that should be addressed
Article
There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new value; and that society needs it as a conservation last resort. I also assessed several possible ethical arguments against pursuing de-extinction: that it is unnatural; that it could cause animal suffering; that it could be ecologically problematic or detrimental to human health; and that it is hubristic. There are reasons in favor of reviving long extinct species, and it can be ethically acceptable to do so. However, the reasons in favor of pursuing de-extinction do not have to do with its usefulness in species conservation; rather, they concern the status of revived species as scientific and technological achievements, and it would be ethically problematic to promote de-extinction as a significant conservation strategy, because it does not prevent species extinctions, does not address the causes of extinction, and could be detrimental to some species conservation efforts. Moreover, humanity does not have a responsibility or obligation to pursue de-extinction of long extinct species, and reviving them does not address any urgent problem. Therefore, legitimate ecological, political, animal welfare, legal, or human health concerns associated with a de-extinction (and reintroduction) must be thoroughly addressed for it to be ethically acceptable. La Ética de Revivir Especies Extintas Hace Mucho Tiempo Sandler.
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CUSTOMIZED SPATIAL CLIMATE MODELS FOR NORTH AMERICA Over the past two decades, researchers at Natural Resources Canada's Canadian Forest Service, in collaboration with the Australian National University (ANU), Environment Canada (EC), and the National Oceanic and Atmospheric Administration (NOAA), have made a concerted effort to produce spatial climate products (i.e., spatial models and grids) covering both Canada and the United States for a wide variety of climate variables and time steps (from monthly to daily), and across a range of spatial resolutions. Here we outline the method used to generate the spatial models, detail the array of products available and how they maybe accessed, briefly describe some of the usage and impact of the models, and discuss anticipated further developments. Our initial motivation in developing these models was to support forestry-related applications. They have since been utilized by a wider range of agencies and researchers. This article is intended to further raise awareness of the strengths and weaknesses of these climate models and to facilitate their wider application. (Page 1611)
Article
Objective evaluations of wildlife reintroductions are vital for increasing the success of future efforts to re-establish endangered species. Attempts to reintroduce one of the most endangered mammals in North America, the black-footed ferret (Mustela nigripes), have been ongoing for 18years with no quantitative assessment of factors related to reintroduction success. We examined relationships between ferret reintroduction success and factors associated with disease outbreaks, release strategies, and the distribution and abundance of their primary prey, prairie dogs (Cynomys sp.), at 11 reintroduction sites. The most important factor related to ferret reintroduction success was a cumulative metric incorporating both size of the area occupied by prairie dogs and density of prairie dog burrows within that area. Each of the four successful sites had prairie dog populations that occupied an area of at least 4300ha. No sites with
Article
A map of ecoregions of the conterminous United States has been compiled to assist managers of aquatic and terrestrial resources in understanding the regional patterns of the realistically attainable quality of these resources. The ecoregions are based on perceived patterns of a combination of causal and integrative factors including land use, land surface form, potential natural vegetation, and soils. A synoptic approach similar to that used to define these ecoregions is also useful for applications of the map. Initial efforts to use the framework are at the state level of resource management; they center on aquatic ecosystems — mainly attainable ranges in chemical quality, biotic assemblages, and lake trophic state.
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Although new technologies may make it possible to bring extinct species back to life, there are ethical, legal, and social ramifications to be addressed.
Article
Aim: Niche conservatism, or the extent to which niches are conserved across space and time, is of special concern for the study of non-native species as it underlies predictions of invasion risk. Based on the occurrence of 28 non-native birds in Europe, we assess to what extent Grinnellian realized niches are conserved during invasion, formulate hypotheses to explain the variation in observed niche changes and test how well species distribution models can predict non-native bird occurrence in Europe. Location: Europe Methods: To quantify niche changes, a recent method that applies kernel smoothers to densities of species occurrence in a gridded environmental space was used. This corrects for differences in the availability of environments between study areas and allows discriminating between ‘niche expansion’ into environments new to the species and ‘niche unfilling’, whereby the species only partially fills its niche in the invaded range. Predictions of non-native bird distribution in Europe were generated using several distribution modeling techniques. Results: Niche overlap between native and non-native bird populations is low, but niche changes are smaller for species having a higher propagule pressure and that were introduced longer ago. Non-native birds in Europe occupy a subset of the environments they inhabit in their native ranges. Niche expansion into novel environments is rare for most species, allowing species distribution models to accurately predict invasion risk. Main conclusions: Because of the recent nature of most bird introductions, species occupy only part of the suitable environments available in the invaded range. This signals that apart from purely ecological factors, patterns of niche conservatism may also be contingent on population-specific historical factors. These results also suggest that many claims of niche differences may be due to a partial filling of the native niche in the invaded range and thus do not represent true niche changes.
Article
Experiments testing biodiversity effects on ecosystem functioning have been criticized on the basis that their random-assembly designs do not reflect deterministic species loss in nature. Because previous studies, and their critics, have focused primarily on plants, however, it is underappreciated that the most consistent such determinism involves biased extinction of large consumers, skewing trophic structure and substantially changing conclusions about ecosystem impacts that assume changing plant diversity alone. Both demography and anthropogenic threats render large vertebrate consumers more vulnerable to extinction, on average, than plants. Importantly, species loss appears biased toward strong interactors among animals but weak interactors among plants. Accordingly, available evidence suggests that loss of a few predator species often has impacts comparable in magnitude to those stemming from a large reduction in plant diversity. Thus, the dominant impacts of biodiversity change on ecosystem functioning appear to be trophically mediated, with important implications for conservation.
Article
We considered the possible effects Passenger Pigeon (Ectopistes migratorius) flocks may have had on the disturbance regime and species composition of presettlement forests in eastern North America. We suggest that the activities of roosting and nesting Passenger Pigeons caused widespread, frequent disturbances in presettlement eastern forests through tree limb and stem breakage and nutrient deposition from pigeon excrement. We suspect that the deposition of fine fuels resulting from such disturbances may have influenced fire intensity and frequency in presettlement forests. Further, we propose that consumption of vast quantities of acorns by pigeons during the spring breeding season may partially explain the dominance of white oak (Quercus alba) throughout much of the presettlement north-central hardwoods region. Consequently, the pigeon's extinction may have facilitated the increase and expansion of northern red oak (Quercus rubra) during the twentieth century. Although it is difficult to accurately quantify how physical and chemical disturbances and mast consumption by Passenger Pigeon flocks affected forest ecology, we suspect they shaped landscape structure and species composition in eastern forests prior to the twentieth century. We believe their impact should be accounted for in estimates of the range of natural variability of conditions in eastern hardwood forests.
Article
It would be an exaggeration to argue that most invasions produce ecosystem impacts, and the term should be reserved for cases in which many species in an ecosystem are affected. However, certain facts suggest that true ecosystem impacts are more common than is normally assumed. First, the term “ecosystem impact” has often been reserved for cases in which the nutrient regime or nutrient cycling is affected, whereas physical structural and other changes in ecosystems ought to be included. Second, as with all ecology, very few systems and species have been studied relative to all those that exist, so it is likely that many ecosystem impacts remain to be detected. Third, there are many types of impacts, many are idiosyncratic, many are subtle, and many are indirect, so it is likely that many impacts have simply not been recognized even in studied systems. Finally, the frequency of the lag phenomenon in invasions implies that at least some existing non-native species that are currently having little or no impact will eventually have much greater ones. These facts suggest that, even if it would be an overstatement to say that most invasions cause ecosystem impacts, it would not be more of an overstatement than the common assertion that very few introduced species have any significant impact. KeywordsFire regime–Habitat structure–Invasional meltdown–Lag time–Nutrient cycling
Article
The availability of detailed environmental data, together with inexpensive and powerful computers, has fueled a rapid increase in predictive modeling of species environmental requirements and geographic distributions. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, absence data are not available for most species. In this paper, we introduce the use of the maximum entropy method (Maxent) for modeling species geographic distributions with presence-only data. Maxent is a general-purpose machine learning method with a simple and precise mathematical formulation, and it has a number of aspects that make it well-suited for species distribution modeling. In order to investigate the efficacy of the method, here we perform a continental-scale case study using two Neotropical mammals: a lowland species of sloth, Bradypus variegatus, and a small montane murid rodent, Microryzomys minutus. We compared Maxent predictions with those of a commonly used presence-only modeling method, the Genetic Algorithm for Rule-Set Prediction (GARP). We made predictions on 10 random subsets of the occurrence records for both species, and then used the remaining localities for testing. Both algorithms provided reasonable estimates of the species’ range, far superior to the shaded outline maps available in field guides. All models were significantly better than random in both binomial tests of omission and receiver operating characteristic (ROC) analyses. The area under the ROC curve (AUC) was almost always higher for Maxent, indicating better discrimination of suitable versus unsuitable areas for the species. The Maxent modeling approach can be used in its present form for many applications with presence-only datasets, and merits further research and development.
Article
The rise of extinction rates associated with human activities has led to a growing interest in identifying extinction-prone taxa and extinction-promoting drivers. Previous work has identified habitat alterations and invasive species as the major drivers of recent bird extinctions. Here, we extend this work to ask how these human-driven impacts differentially affect extinction-prone taxa, and if any specific driver promotes taxonomic homogenization of avifauna. Like most previous studies, our analysis is based on global information of extinction drivers affecting threatened and extinct bird species from the IUCN Red List. Unlike previous studies, we employ a multivariate statistical framework that allows us to identify the main gradients of variation in extinction drivers. By using these gradients, we show that bird families with the highest extinction risk are primarily associated with threats posed by invasive species, once species richness and phylogeny are taken into account. As expected, the negative impact of invasive species was higher on island species, but our results also showed that it was particularly high in those species with small distribution ranges. On the other hand, mainland species and island species with large ranges tended to be affected by habitat destruction. Thus the impacts of invasive species promote the process of taxonomic homogenization among islands and between islands and continents. Consequently, introduced species may increase biotic homogenization not only directly, as generally believed, but also indirectly through their disproportional impact on endemic species imperilment.
Article
Ecosystems worldwide are losing some species and gaining others, resulting in an interchange of species that is having profound impacts on how these ecosystems function. However, research on the effects of species gains and losses has developed largely independently of one another. Recent conceptual advances regarding effects of species gain have arisen from studies that have unraveled the mechanistic basis of how invading species with novel traits alter biotic interactions and ecosystem processes. In contrast, studies on traits associated with species loss are fewer, and much remains unknown about how traits that predispose species to extinction affect ecological processes. Species gains and losses are both consequences and drivers of global change; thus, explicit integration of research on how both processes simultaneously affect ecosystem functioning is key to determining the response of the Earth system to current and future human activities.
Article
Many of the species at greatest risk of extinction from anthropogenic climate change are narrow endemics that face insurmountable dispersal barriers. In this review, I argue that the only viable option to maintain populations of these species in the wild is to translocate them to other locations where the climate is suitable. Risks of extinction to native species in destination areas are small, provided that translocations take place within the same broad geographic region and that the destinations lack local endemics. Biological communities in these areas are in the process of receiving many hundreds of other immigrant species as a result of climate change; ensuring that some of the 'new' inhabitants are climate-endangered species could reduce the net rate of extinction.
Article
The ranges of plants and animals are moving in response to recent changes in climate. As temperatures rise, ecosystems with 'nowhere to go', such as mountains, are considered to be more threatened. However, species survival may depend as much on keeping pace with moving climates as the climate's ultimate persistence. Here we present a new index of the velocity of temperature change (km yr(-1)), derived from spatial gradients ( degrees C km(-1)) and multimodel ensemble forecasts of rates of temperature increase ( degrees C yr(-1)) in the twenty-first century. This index represents the instantaneous local velocity along Earth's surface needed to maintain constant temperatures, and has a global mean of 0.42 km yr(-1) (A1B emission scenario). Owing to topographic effects, the velocity of temperature change is lowest in mountainous biomes such as tropical and subtropical coniferous forests (0.08 km yr(-1)), temperate coniferous forest, and montane grasslands. Velocities are highest in flooded grasslands (1.26 km yr(-1)), mangroves and deserts. High velocities suggest that the climates of only 8% of global protected areas have residence times exceeding 100 years. Small protected areas exacerbate the problem in Mediterranean-type and temperate coniferous forest biomes. Large protected areas may mitigate the problem in desert biomes. These results indicate management strategies for minimizing biodiversity loss from climate change. Montane landscapes may effectively shelter many species into the next century. Elsewhere, reduced emissions, a much expanded network of protected areas, or efforts to increase species movement may be necessary.
Article
Many ecosystems are rapidly being transformed into new, non-historical configurations owing to a variety of local and global changes. We discuss how new systems can arise in the face of primarily biotic change (extinction and/or invasion), primarily abiotic change (e.g. land use or climate change) and a combination of both. Some changes will result in hybrid systems retaining some original characteristics as well as novel elements, whereas larger changes will result in novel systems, which comprise different species, interactions and functions. We suggest that these novel systems will require significant revision of conservation and restoration norms and practices away from the traditional place-based focus on existing or historical assemblages.
Article
Two experiments have been performed to clone the bucardo, an extinct wild goat. The karyoplasts were thawed fibroblasts derived from skin biopsies, obtained and cryopreserved in 1999 from the last living specimen, a female, which died in 2000. Cytoplasts were mature oocytes collected from the oviducts of superovulated domestic goats. Oocytes were enucleated and coupled to bucardo's fibroblasts by electrofusion. Reconstructed embryos were cultured for 36h or 7d and transferred to either Spanish ibex or hybrid (Spanish ibex malex domestic goat) synchronized recipients. Embryos were placed, according to their developmental stage, into the oviduct or into the uterine horn ipsilateral to an ovulated ovary. Pregnancy was monitored through their plasmatic PAG levels. In Experiment 1, 285 embryos were reconstructed and 30 of them were transferred at the 3- to 6-cells stage to 5 recipients. The remaining embryos were further cultured to day 7, and 24 of them transferred at compact morula/blastocyst stage to 8 recipients. In Experiment 2, 154 reconstructed embryos were transferred to 44 recipients at the 3- to 6-cells stage. Pregnancies were attained in 0/8 and 7/49 of the uterine and oviduct-transferred recipients, respectively. One recipient maintained pregnancy to term, displaying very high PAG levels. One morphologically normal bucardo female was obtained by caesarean section. The newborn died some minutes after birth due to physical defects in lungs. Nuclear DNA confirmed that the clone was genetically identical to the bucardo's donor cells. To our knowledge, this is the first animal born from an extinct subspecies.
Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves
  • G Church
  • E Regis
Church, G., Regis, E., 2012. Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves. Basic Books, New York, NY.
Guidelines for Reintroductions and Other Conservation Translocations
  • Iucn
IUCN, 2013. Guidelines for Reintroductions and Other Conservation Translocations.
Customized spatial climate models for North America
  • D Mckenney
  • M Hutchinson
  • P Papadopol
  • K Lawernce
  • J Pedlar
  • K Campbell
  • E Milewska
  • R Hopkinson
  • D Price
  • T Owen
McKenney, D., Hutchinson, M., Papadopol, P., Lawernce, K., Pedlar, J., Campbell, K., Milewska, E., Hopkinson, R., Price, D., Owen, T., 2011. Customized spatial climate models for North America. Natural Resource Canada.
How to bring passenger pigeons all the way back
  • Novak
Novak, B., 2013. How to bring passenger pigeons all the way back. TEDxDeExtinction.
Maximum entropy modeling of species geographic distributions
  • Phillips
Phillips, S.J., Anderson, R.P., Schapire, R.E., 2006. Maximum entropy modeling of species geographic distributions. Ecol. Model. 190, 231-259. http://dx.doi.org/10.1016/j. ecolmodel.2005.03.026.
Novel ecosystems: implications for conservation and restoration
  • Hobbs