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Individuals with disabilities may engage in challenging behavior to escape aversive stimuli, like academic tasks or non-preferred foods. Interventions to reduce these behaviors often employ escape extinction; that is, the implementer withholds escape following challenging behavior. Escape extinction can increase risk of injury, restrict autonomy, and worsen the learner-implementer relationship. To mitigate collateral effects, interventions can use strategies without escape extinction (i.e., escape-based); that is, implementers can provide escape contingent on challenging behavior during intervention, in conjunction with other intervention components. However, no comprehensive syntheses of these interventions have been conducted. We identified 39 articles that included escape-based interventions, which contained 273 single-case designs. Escape-based interventions were associated with lower levels of challenging behavior and higher levels of adaptive behavior than baseline conditions. Most comparisons between escape-based and escape extinction interventions showed no functional relation, indicating that escape extinction may not add substantial benefit to intervention efficacy., Author(s): Kate T. Chazin [sup.1], Marina S. Velez [sup.1], Jennifer R. Ledford [sup.1] Author Affiliations: (1) grid.152326.1, 0000 0001 2264 7217, Department of Special Education, Vanderbilt University, , Peabody Box [...]

The population size has far-reaching effects on the fitness of a population that in turn influences the population extinction or persistence. Understanding the density- and age-dependent factors will facilitate more accurate predictions about the population dynamics and its asymptotic behavior. In this paper, we develop a rigorous mathematical analysis of the study of positive and negative effects of the increased population density in the classical nonlinear age-structured population model. One of the main results expresses the global stability of the system in terms of the newborn function only. We establish the existence of a threshold population size implying the population extinction, which is well known in the population dynamics as the Allee effect. Bibliography: 18 titles. Illustrations: 1 figure. Dedicated to N. N. Uraltseva on the occasion of her 85th birthday, 1 Introduction In biological populations, the density-dependent regulation represents a change in individual fitness caused by changes in the population size or density. The negative density- dependence, often explained by [...]

This paper offers a paleobiological perspective on the debate concerning the possible use of biotechnology to bring back extinct species. One lesson from paleobiology is that extinction selectivity matters in addition to extinction rates and extinction magnitude. Combining some of Darwin's insights about artificial selection with the theory of species selection that paleobiologists developed in the 1970s and 1980s provides a useful context for thinking about de-extinction. Using recent work on the prioritization of candidate species for de-extinction as a test case, the paper argues that de-extinction would be a form of artificial species selection in which humans influence which species persist vs. go extinct. This points to a serious gap in our ethical theory: Much work has been done to clarify the value(s) of biological diversity, but we also need theoretical guidance for decisions that amount to species sorting, and that will shape the macroevolutionary future., Author(s): Derek D. Turner [sup.1] Author Affiliations: (1) Connecticut College, 0000 0001 2343 1311, grid.254656.6, , 270 Mohegan Avenue, 06320, New London, CT, USA Introduction This paper offers a paleontological [...]

Advances in biotechnology mean that it may soon be possible to recreate previously extinct species. This has led to an emerging debate within bioethics about whether we ought to reintroduce extinct species into our ecosystems. In this paper, we discuss the role that biodiversity could play in this debate. Many believe that biodiversity is a good that should be protected. We argue that if biodiversity is a good, then this suggests it should also be promoted, including by reintroducing previously extinct species. We begin by outlining different ways in which biodiversity could be conceptualized, and then analyze various accounts of its value. We suggest no approach justifies an asymmetry between 'protecting' biodiversity by conserving species alive today, and 'creating' biodiversity by introducing previously extinct species. This suggests that if we have reasons stemming from biodiversity to protect species from extinction, we will have similar reasons to reintroduce previously extinct species. We close by asking whether arguments from biodiversity speak in favor of introducing some novel species into the ecosystem., Author(s): Christopher Gyngell [sup.1] , Julian Savulescu [sup.1] [sup.2] Author Affiliations: (1) Oxford Uehiro Centre for Practical Ethics, Oxford University, 0000 0004 1936 8948, grid.4991.5, , Oxford, UK (2) School [...]

This article will explore a problem which is related to our moral obligations towards species. Although the re-creation of extinct animals has been discussed to some degree both in lay deliberations as well as by scientists, advocates tend to emphasize the technological and scientific value of such an endeavour, and the 'coolness' factor (Sherkow and Greely Science, 340(6128), 32-33, 2013 (See CR32)). This article will provide an argument in favour of re-creation based on normative considerations. The environmentalist community generally accepts that it is wrong to exterminate species, for reasons beyond any instrumental value these species may have. It is often also claimed that humanity has a collective responsibility to either preserve or at least to not exterminate species. These two beliefs are here assumed to be correct. The argument presented here departs from and places these two ideas in a deontological framework, from which it is argued that when humanity causes the extinction of a species, this is a moral transgression, entailing a residual obligation. Such an obligation implies a positive duty to mitigate any harm caused by our moral failure. In light of recent scientific progress in the field of genetic engineering, it will be argued that humanity has a prima facie obligation to re-create species whose extinction mankind may have caused, also known as de-extinction., Author(s): Karim Jebari[sup.1] Author Affiliations: (1) Institute for Futures Studies, Holländargatan 13, 101 31, Stockholm, Sweden Introduction In its Earth Charter , the United Nations Educational, Scientific and Cultural Organization [...]

Much has been made of the objects present in Elizabeth Bowen's fiction, which is no surprise given her increasing focus on the external world over the internal one. (1) For [...]

About 10,000 years ago, one could have mistaken the Egyptian landscape for that of East Africa today. Instead of vast arid deserts, the region north of Aswan held enough annual [...]

Palaeontologists have charted 300 million years of Earth's history in breathtaking detail. Palaeontologists have charted 300 million years of Earth's history in breathtaking detail., Author(s): Ewen Callaway Author Affiliations: Supercomputer scours fossil record for Earth's hidden extinctions Trilobites disappeared from the fossil record during the mass extinction at the end of the Permian period, [...]

For centuries, biogeographers have examined the factors that produce patterns of biodiversity across regions. The study of islands has proved particularly fruitful and has led to the theory that geographic area and isolation influence species colonization, extinction and speciation such that larger islands have more species and isolated islands have fewer species (that is, positive species-area and negative species-isolation relationships) (1-4). However, experimental tests of this theory have been limited, owing to the difficulty in experimental manipulation of islands at the scales at which speciation and long-distance colonization are relevant (5). Here we have used the human-aided transport of exotic anole lizards among Caribbean islands as such a test at an appropriate scale. In accord with theory, as anole colonizations have increased, islands impoverished in native species have gained the most exotic species, the past influence of speciation on island biogeography has been obscured, and the species-area relationship has strengthened while the species-isolation relationship has weakened. Moreover, anole biogeography increasingly reflects anthropogenic rather than geographic processes. Unlike the island biogeography of the past that was determined by geographic area and isolation, in the Anthropocene--an epoch proposed for the present time interval--island biogeography is dominated by the economic isolation of human populations., The number of species (that is, richness) on islands is theorized to be a function of colonization and in situ speciation that add species, and extinction that subtracts them (1-6). [...]

There are three senses of extinction: the now widely discussed sixth great extinction event (which we can begin to imagine, witnessed by humans even if in anticipation); extinction by humans [...]

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1600-0706.2010.18713.x Byline: Alexandro Caruso, Goran Thor, Tord Snall Abstract: Metapopulation models are often used for understanding and predicting species dynamics in fragmented landscapes. Several models have been proposed depending on e.g. the relative importance of patch dynamics on the metapopulation dynamics. Dead wood is a dynamic substrate patch, and species that are confined to such patches have experienced a high degree of habitat loss in managed forests. Little is, however, known about how the population dynamics of epixylic species are affected by the fast dynamics of their substrate patches. We quantified the effect of local patch conditions and metapopulation processes on colonizations and extinctions of epixylic lichen species in a managed boreal forest landscape. This was done by twice surveying seven lichen metapopulations on 293 stumps in 30 stands of ages covering the duration of the dynamic patches (stumps). We also investigated the relative importance of local stochastic extinctions from stumps that remained available, and deterministic extinctions due to stump surface disappearance. We found importance of a decay gradient, surrounding metapopulation size, and local population sizes, in driving the colonization-extinction dynamics of epixylic lichens. The species were sorted along the stump decay gradient. Increasing surrounding metapopulation size was associated with increased colonization rates, and increasing local population size decreased lichen extinction rates. Finally, both local stochastic extinctions and deterministic extinctions due to patch disappearance occur, confirming that the long-term persistence of epixylic lichens depends on colonization rates that compensate for stochastic population extinctions as well as deterministic extinctions. Author Affiliation: (1)Dept of Ecology, Swedish University of Agricultural Sciences, PO Box 7044, SE-750 07 Uppsala, Sweden Article History: Paper manuscript accepted 20 April 2010 Article note: A. Caruso, Dept of Ecology, Swedish University of Agricultural Sciences, PO Box 7044, SE-750 07 Uppsala, Sweden. E-mail: alexandro.caruso@ekol.slu.se

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1600-0706.2010.18666.x Byline: Stephen F. Matter, Jens Roland Abstract: While many studies have examined factors potentially impacting the rate of local population extinction, few experimental studies have examined the consequences of extinction for spatial population dynamics. Here we report results from a large-scale, long-term experiment examining the effects of local population extinction for the dynamics of surrounding populations. From 2001-2008 we removed all adult butterflies from two large, neighboring populations within a system of 17 subpopulations of the Rocky Mountain Apollo butterfly, Parnassius smintheus. Surrounding populations were monitored using individual, mark-recapture methods. We found that population removal decreased immigration to surrounding populations in proportion to their connectivity to the removed populations. Correspondingly, within-generation population abundance declined. Despite these effects, we saw little consistent impact between generations. The extinction rates of surrounding populations were unaffected and local population growth was not consistently reduced by the lack of immigration. The broader results show that immigration affects local abundance within generations, but dynamics are mediated by density-dependence within populations and by broader density-independent factors acting between generations. The loss of immigrants resulting from extinction has little impact on the persistence of local populations in this system. Author Affiliation: (1)Dept of Biological Sciences, Univ. of Cincinnati, Cincinnati, OH 45220, USA (2)Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB T5K 1X4, Canada Article History: Paper manuscript accepted 26 April 2010 Article note: S. F. Matter, Dept of Biological Sciences, Univ. of Cincinnati, Cincinnati, OH 45220, USA. mattersf@uc.edu

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1600-0706.2010.18616.x Byline: Amanda K. Gibson, Jorge I. Mena-Ali, Michael E. Hood Abstract: Global declines in biodiversity create an urgent need to address the impact of infectious disease in the small and fragmented populations that characterize threatened species. However, the paucity of empirical data provides little ability to predict whether disease generally accelerates threatened species towards extinction or becomes less important as populations decline. This study tests whether plant species threatened with extinction exhibit lower disease frequencies and lower overall parasite species richness while also experimentally testing for the effect of physiological disease resistance. Herbarium surveys of the genus Silene revealed that anther-smut disease was significantly less frequent in threatened species than non-threatened species, and this effect was not constrained by the host phylogeny or by physiological resistance. Moreover, analysis across a much broader range of plants (using US Federal designations) revealed that species with endangered status had significantly lower species richness of fungal pathogens than closely-related, non-endangered species. These results support the role of host ecology, rather than physiological resistance or phylogeny, in determining overall lower incidences and diversity of diseases in plant species threatened by extinction. Low disease incidence accompanied by susceptibility in threatened species may result from selection against costly resistance genes in the absence of disease. Author Affiliation: (1)Dept of Biology, McGuire Life Sciences Building, Amherst College, Rts 9 and 116, Amherst, MA 01002-5000, USA Article History: Paper manuscript accepted 7 May 2010 Article note: M. E. Hood, Dept of Biology, McGuire Life Sciences Building, Amherst College, Rts 9 and 116, Amherst, MA 01002-5000, USA. E-mail: mhood@amherst.edu

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1600-0706.2010.18557.x Byline: Benjamin Baiser, Gareth J. Russell, Julie L. Lockwood Abstract: Human induced global change has greatly altered the structure and composition of food webs through the invasion of non-native species and the extinction of native species. Much attention has been paid to the effects of species deletions on food web structure and stability. However, recent empirical evidence suggests that for most taxa local species richness has increased as successful invasions outpace extinctions at this scale. This pattern suggests that food webs, which represent feeding interactions at the local scale, may be increasing in species richness. Knowledge of how food web structure relates to invasive species establishment and the effect of successful invaders on subsequent food web structure remains an unknown but potentially important aspect of global change. Here we explore the effect of food web topology on invasion success in model food webs to develop hypotheses about how the distribution of biodiversity across trophic levels affects the success of invasion at each trophic level. Our results suggest a connectance (C) based framework for predicting invasion success in food webs due to the way that C constrains the number of species at each trophic level and thus the number of potential predators and prey for an invader at a given trophic level. We use the relationship between C and the proportion of species at each trophic level in 14 well studied food webs to make the following predictions; 1) the success of basal invaders will increase as C increases due to the decrease in herbivores in high C webs, 2) herbivore invasion success will decrease as C increases due to the decrease in the proportion of basal species and increase in intermediate species and omnivores in high C webs. 3) Top predator invasion success will increase as C increases due to the increase in intermediate prey species. However, it is not clear how the relative influence of trophic structure compares to empirically known predictors of invasion success such as invader traits, propagule pressure, and resource availability. Author Affiliation: (1)Graduate Program in Ecology and Evolution, and Dept of Ecology, Evolution and Natural Resources, Rutgers Univ., New Brunswick, NJ 08901, USA (2)Harvard Forest, Harvard Univ., 324 North Main Street, Petersham, MA 01366 USA (3)Dept of Biologicall Sciences, New Jersey Inst. of Technology, Newark, NJ 07102, USA, and Dept of Biological Sciences, Rutgers Univ., Newark, NJ 07102, USA Article History: Paper manuscript accepted 7 May 2010 Article note: B. Baiser, Graduate Program in Ecology and Evolution, and Dept of Ecology, Evolution and Natural Resources, Rutgers Univ., New Brunswick, NJ 08901, USA. E-mail: bbaiser@fas.harvard.edu

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2010.01461.x Byline: TRACY M. ROUT (*[double dagger]), DEAN HEINZE ([dagger]), MICHAEL A. McCARTHY (*) Keywords: conservation management; decision theory; dodo; ivory-billed woodpecker; mountain pygmy-possum; optimal monitoring; risk analysis; uncertainty Abstract: Abstract: Statements of extinction will always be uncertain because of imperfect detection of species in the wild. Two errors can be made when declaring a species extinct. Extinction can be declared prematurely, with a resulting loss of protection and management intervention. Alternatively, limited conservation resources can be wasted attempting to protect a species that no longer exists. Rather than setting an arbitrary level of certainty at which to declare extinction, we argue that the decision must trade off the expected costs of both errors. Optimal decisions depend on the cost of continued intervention, the probability the species is extant, and the estimated value of management (the benefit of management times the value of the species). We illustrated our approach with three examples: the Dodo (Raphus cucullatus), the Ivory-billed Woodpecker (U.S. subspecies Campephilus principalis principalis), and the mountain pygmy-possum (Burramys parvus). The dodo was extremely unlikely to be extant, so managing and monitoring for it today would not be cost-effective unless the value of management was extremely high. The probability the Ivory-billed woodpecker is extant depended on whether recent controversial sightings were accepted. Without the recent controversial sightings, it was optimal to declare extinction of the species in 1965 at the latest. Accepting the recent controversial sightings, it was optimal to continue monitoring and managing until 2032 at the latest. The mountain pygmy-possum is currently extant, with a rapidly declining sighting rate. It was optimal to conduct as many as 66 surveys without sighting before declaring the species extinct. The probability of persistence remained high even after many surveys without sighting because it was difficult to determine whether the species was extinct or undetected. If the value of management is high enough, continued intervention can be cost-effective even if the species is likely to be extinct. Abstract (Spanish): Asignacion Optima de Recursos para la Conservacion de Especies que Pueden Estar Extintas Resumen. Las declaraciones de extincion siempre seran inciertas debido a la deteccion imperfecta de especies en su medio. Se pueden cometer dos errores al declarar extinta a una especie. La extincion puede ser declarada prematuramente, con la consiguiente perdida de proteccion e intervenciones de manejo. Alternativamente, los recursos limitados para la conservacion pueden ser desperdiciados intentando proteger a una especie que ya no existe. En lugar de fijar un nivel arbitrario de certidumbre para declarar la extincion, argumentamos que la decision debe considerar los costos esperados de ambos errores. Las decisiones optimas dependen del costo de la intervencion continua, la probabilidad de que la especie exista y el valor estimado del manejo (el beneficio del manejo multiplicado por el valor de la especie). Ilustramos nuestro metodo con tres ejemplos: el dodo (Raphus cucullatus), Campephilus principalis principalis, y Burramys parvus. Es extremadamente improbable que el dodo exista, asi que su manejo y monitoreo no seria rentable a menos que el valor del manejo fuera extremadamente alto. La probabilidad de que C. p. principalis exista dependio de la aceptacion de los controversiales avistamientos recientes. Sin los controversiales avistamientos recientes, fue optimo declarar extinta a la especie en 1965 a mas tardar. Aceptando los controversiales avistamientos recientes, fue optimo continuar monitoreando y manejando hasta 2032. Burramys parvus existe actualmente, con una tasa de avistamiento en rapida declinacion. Fue optimo realizar hasta 66 muestreos sin avistamientos antes de declarar extinta a la especie. La probabilidad de persistencia permanecio alta aun despues de muchos muestreos sin avistamiento porque fue dificil determinar si la especie estaba extinta o no detectada. Si el valor de manejo es lo suficientemente alto, la intervencion continua puede ser rentable aun si la especie probablemente esta extinta. Author Affiliation: (*)Commonwealth Environment Research Facility (Applied Environmental Decision Analysis), School of Botany, University of Melbourne, Australia ([dagger])Department of Primary Industries, Parks, Water and Environment, Tasmania, Australia Article History: Paper submitted August 18, 2009; revised manuscript accepted October 22, 2009. Article note: ([double dagger]) email tmrout@unimelb.edu.au

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2010.01464.x Byline: LIAN PIN KOH* (*), JABOURY GHAZOUL (*) Keywords: agriculture; biodiversity crisis; countryside biogeography; equilibrium theory; forest regeneration; power model; reconciliation ecology; secondary succession Abstract: Abstract: Application of island biogeography theory to prediction of species extinctions resulting from habitat loss is based on the assumption that the transformed landscape matrix is completely inhospitable to the taxa considered, despite evidence demonstrating the nontrivial influence of matrix on populations within habitat remnants. The island biogeography paradigm therefore needs refining to account for specific responses of taxa to the area of habitat 'islands' and to the quality of the surrounding matrix. We incorporated matrix effects into island theory by partitioning the slope (z value) of species-area relationships into two components: [gamma], a constant, and [sigma], a measure of taxon-specific responses to each component of a heterogeneous matrix. We used our matrix-calibrated model to predict extinction and endangerment of bird species resulting from land-use change in 20 biodiversity hotspots and compared these predictions with observed numbers of extinct and threatened bird species. We repeated this analysis with the conventional species-area model and the countryside species-area model, considering alternative z values of 0.35 (island) or 0.22 (continental). We evaluated the relative strength of support for each of the five candidate models with Akaike's information criterion (AIC). The matrix-calibrated model had the highest AIC weight (w.sub.i = 89.21%), which means the weight of evidence in support of this model was the optimal model given the set of candidate models and the data. In addition to being a valuable heuristic tool for assessing extinction risk, our matrix-calibrated model also allows quantitative assessment of biodiversity benefits (and trade-offs) of land-management options in human-dominated landscapes. Given that processes of secondary regeneration have become more widespread across tropical regions and are predicted to increase, our matrix-calibrated model will be increasingly appropriate for practical conservation in tropical landscapes. Abstract (Spanish): Un Modelo Especies-Area Calibrado para la Matriz para Predecir las Perdidas de Biodiversidad Debido a Cambios en el Uso de Suelo Resumen. La aplicacion de la teoria de biogeografia de islas a la prediccion de extinciones de especies como resultado de la perdida de habitat se basa en el supuesto de que la matriz de paisaje transformado es inhospito para los taxa considerados, no obstante la evidencia que demuestra la influencia no trivial de la matriz sobre las poblaciones en los remanentes de habitat. Por lo tanto, el paradigma de la biogeografia de islas requiere refinacion para explicar las respuestas especificas de los taxa al area de las 'islas' de habitat y a la calidad de la matriz circundante. Incorporamos los efectos de la matriz en la teoria de islas dividiendo la pendiente (valor z) de las relaciones especies-area en dos componentes: [gamma], una constante, y [sigma], una medida de las respuestas especificas del taxon a cada componente de una matriz heterogenea. Utilizamos nuestro modelo calibrado para la matriz para predecir la extincion y estatus de riesgo de especies de aves como resultado del cambio en el uso de suelo en 20 sitios de importancia para la biodiversidad y comparamos estas predicciones con el numero observado de especies de aves extintas y amenazadas. Repetimos este analisis con el modelo especies-area convencional y el modelo especies-area rural, considerando valores alternativos de z de 0.35 (isla) o 0.22 (continental). Evaluamos la solidez relativa del soporte de cada uno de los cinco modelos con el criterio de informacion Akaike (AIC). El modelo calibrado para la matriz tuvo el mayor AIC (w.sub.i = 89.21%), lo que significa que el peso de la evidencia que soporta este modelo fue el modelo optimo dado el conjunto de modelos candidatos y los datos. Ademas de ser una herramienta heuristica valiosa para evaluar el riesgo de extincion, nuestro modelo calibrado para la matriz tambien permite una evaluacion cuantitativa de los beneficios para la biodiversidad de las opciones de manejo de suelo en paisajes dominados por la actividad humana. Debido que los procesos de regeneracion secundaria se han extendido en las regiones tropicales y que se espera que incrementen, nuestro modelo calibrado para la matriz cada vez sera mas apropiado para la conservacion en paisajes tropicales. Author Affiliation: (*)Institute of Terrestrial Ecosystems, ETH Zurich, CHN G 74.2, Universitatstrasse 16, 8092 Zurich, Switzerland Article History: Paper submitted May 22, 2009; revised manuscript accepted October 27, 2009. Article note: (*) email lian.koh@env.ethz.ch

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2009.01429.x Byline: SHELLY LACHISH (*[dagger][dagger]), HAMISH McCALLUM ([dagger]s.), DYDEE MANN ([double dagger]), CHRISSY E. PUKK ([double dagger]), MENNA E. JONES ([dagger][double dagger]) Keywords: disease suppression; infectious disease management; selective culling; Tasmanian devil facial tumor disease; threatened species Abstract: Abstract: Sustainable strategies to manage infectious diseases in threatened wildlife are still lacking despite considerable concern over the global increase in emerging infectious diseases of wildlife and their potential to drive populations to extinction. Selective culling of infected individuals will often be the most feasible option to control infectious disease in a threatened wildlife host, but has seldom been implemented or evaluated as a management tool for the conservation of threatened species. The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction by an infectious cancer, devil facial tumor disease (DFTD). We assess the success of an adaptive management trial involving selective culling of infected Tasmanian devils to control DFTD. Demographic and epidemiological parameters indicative of disease progression and impact were compared between the management site and a comparable unmanaged control site. Selective culling of infected individuals neither slowed rate of disease progression nor reduced population-level impacts of this debilitating disease. Culling mortality simply compensated for disease mortality in this system. Failure of selective culling to impede DFTD progress and reduce its impacts in the managed population was attributed to DFTD's frequency-dependent nature, its long latent period and high degree of infectivity, and the presence of a cryptic hidden disease reservoir or continual immigration of diseased individuals. We suggest that increasing the current removal rate and focusing removal efforts prior to the breeding season are options worth pursuing for future management of DFTD in this population. On the basis of our experience, we suggest that disease-management programs for threatened wildlife populations be developed on the principles of adaptive management and utilize a wide variety of strategies with regular reviews and adaptation of strategies undertaken as new information is obtained. Abstract (Spanish): Evaluacion de la Extraccion Selectiva de Individuos Infectados para Controlar la Enfermedad de Tumor Facial en el Demonio de Tasmania Resumen: No obstante la creciente preocupacion por el incremento global de enfermedades infecciosas emergentes y su potencial para llevar a las especies a la extincion, aun se carece de estrategias sustentables para el manejo de enfermedades infecciosas de la vida silvestre amenazada. La extraccion selectiva de individuos infectados a menudo sera la opcion mas viable para controlar una enfermedad infecciosa en una especie amenazada, pero casi no se ha implementado o evaluado como una herramienta de manejo para la conservacion de especies amenazadas. El Demonio de Tasmania (Sarcophilus harrisii) esta amenazado por un cancer infeccioso, la enfermedad de tumor facial del demonio (ETFD). Evaluamos el exito de una prueba de manejo adaptativo para controlar ETFD que involucro la extraccion selectiva de Demonios de Tasmania infectados. Los parametros demograficos y epidemiologicos indicadores del progreso e impacto de la enfermedad fueron comparados entre el sitio de manejo y un sitio control sin manejo. La extraccion selectiva de los individuos infectados no disminuyo la tasa de progresion de la enfermedad ni redujo los impactos de esta enfermedad debilitante en la poblacion. La mortalidad selectiva simplemente compenso la mortalidad de la enfermedad en este sistema. El fracaso de la extraccion selectiva para impedir el progreso de EFTD y reducir sus impactos en la poblacion manejada fue atribuido a la naturaleza dependiente de la frecuencia de ETFD, su largo periodo de latencia y alto grado de infectividad, y la presencia de un reservorio criptico de la enfermedad o la inmigracion continua de individuos enfermos. Sugerimos que el incremento de la actual tasa de remocion y concentrar los esfuerzos de remocion antes de la epoca reproductiva son opciones que vale pena explorar para el manejo futuro de EFTD en esta poblacion. Con base en nuestra experiencia, sugerimos que los programas de manejo de enfermedades en poblaciones de vida silvestre amenazada sean desarrollados con base en los principios del manejo adaptativo y utilicen una amplia variedad de estrategias con revisiones frecuentes y la adaptacion de las estrategias a medida que se obtenga informacion nueva. Author Affiliation: (*)School of Integrative Biology, University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia ([dagger])School of Zoology, University of Tasmania, Private Bag 5, Churchill Avenue, Hobart 7001, Tasmania, Australia ([double dagger])Department of Primary Industries and Water, 134 Macquarie Street, Hobart, 7001 Tasmania, Australia Article History: Paper submitted April 26, 2009; revised manuscript accepted September 9, 2009. Article note: ([dagger][dagger]) Current address: School of Zoology, University of Tasmania, Private Bag 5, Hobart, Tasmania 7001, Australia, email s.lachish@uq.edu.au (s.) Current address: Griffith School of Environment, Griffith University, Nathan, Brisbane, Queensland 4101, Australia.

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2009.01428.x Byline: JAMES A. ESTES (*), M. TIM TINKER ([dagger]), JAMES L. BODKIN ([double dagger]) Keywords: Alaska; interaction strength; kelp; phase state; recovery; sea otter; sea urchins Abstract: Abstract: Recovery criteria for depleted species or populations normally are based on demographic measures, the goal being to maintain enough individuals over a sufficiently large area to assure a socially tolerable risk of future extinction. Such demographically based recovery criteria may be insufficient to restore the functional roles of strongly interacting species. We explored the idea of developing a recovery criterion for sea otters (Enhydra lutris) in the Aleutian archipelago on the basis of their keystone role in kelp forest ecosystems. We surveyed sea otters and rocky reef habitats at 34 island-time combinations. The system nearly always existed in either a kelp-dominated or deforested phase state, which was predictable from sea otter density. We used a resampling analysis of these data to show that the phase state at any particular island can be determined at 95% probability of correct classification with information from as few as six sites. When sea otter population status (and thus the phase state of the kelp forest) was allowed to vary randomly among islands, just 15 islands had to be sampled to estimate the true proportion that were kelp dominated (within 10%) with 90% confidence. We conclude that kelp forest phase state is a more appropriate, sensitive, and cost-effective measure of sea otter recovery than the more traditional demographically based metrics, and we suggest that similar approaches have broad potential utility in establishing recovery criteria for depleted populations of other functionally important species. Abstract (Spanish): Utilizacion de la Funcion Ecologica para Desarrollar Criterios de Recuperacion para Especies Disminuidas: Nutrias Marinas y Bosques de Algas en el Archipielago Aleutiano Resumen: Los criterios para la recuperacion de especies o poblaciones disminuidas generalmente se basan en medidas demograficas, con la meta de mantener suficientes individuos en un area suficientemente extensa para asegurar un riesgo de extincion futura socialmente tolerable. Tales criterios de recuperacion basados en demografia pueden ser insuficientes para restaurar los papeles funcionales de especies con interacciones estrechas. Exploramos la idea de desarrollar un criterio de recuperacion para nutrias marinas (Enhydra lutris) en el archipielago Aleutiano con base en su papel clave en los ecosistemas de bosques de algas. Muestreamos nutrias marinas y habitats arrecifales rocosos en 34 combinaciones isla-tiempo. El sistema casi siempre existio en una condicion de estado dominado por algas o deforestado, lo cual era pronosticable a partir de la densidad de nutrias marinas. Usamos un analisis de remuestreo de estos datos para mostrar que la condicion de estado en una isla particular puede ser determinada con un 95% de probabilidad de clasificacion correcta con informacion de seis sitios. Cuando se permitio que el estatus de la poblacion de nutrias marinas (y por lo tanto, la condicion de estado del bosque de algas) variara aleatoriamente entre islas, solo se tuvieron que muestrear 15 islas para estimar la verdadera proporcion que estaba dominada por algas (dentro de 10%) con una confianza de 90%. Concluimos que la condicion de estado del bosque de alfas es una medida mas apropiada, sensible y rentable de la recuperacion de nutrias marinas que las medidas mas tradicionales basadas en demografia, y sugerimos que metodos similares tienen una amplia utilidad potencial para el establecimiento de criterios de recuperacion de poblaciones disminuidas de otras especies funcionalmente importantes. Author Affiliation: (*)Department of Ecology and Evolutionary Biology, Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, CA 95060, U.S.A. emailjestes@ucsc.edu ([dagger])U.S. Geological Survey, 100 Shaffer Road, Santa Cruz, CA 95060, U.S.A. ([double dagger])U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, U.S.A. Article History: Paper submitted May 15, 2009; revised manuscript accepted August 25, 2009.

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2009.01398.x Byline: MELINDA L. MOIR (*[dagger][dagger]), PETER A. VESK (*), KARL E.C. BRENNAN ([dagger]), DAVID A. KEITH ([double dagger]), LESLEY HUGHES (s.), MICHAEL A. McCARTHY (*) Keywords: extinction risk; host specificity; host switching; insects; invertebrates; plant-insect interactions; parasites; species loss Abstract: Abstract: Coextinction is a poorly quantified phenomenon, but results of recent modeling suggest high losses to global biodiversity through the loss of dependent species when hosts go extinct. There are critical gaps in coextinction theory, and we outline these in a framework to direct future research toward more accurate estimates of coextinction rates. Specifically, the most critical priorities include acquisition of more accurate host data, including the threat status of host species; acquisition of data on the use of hosts by dependent species across a wide array of localities, habitats, and breadth of both hosts and dependents; development of models that incorporate correlates of nonrandom host and dependent extinctions, such as phylogeny and traits that increase extinction-proneness; and determination of whether dependents are being lost before their hosts and adjusting models accordingly. Without synergistic development of better empirical data and more realistic models to estimate the number of cothreatened species and coextinction rates, the contribution of coextinction to global declines in biodiversity will remain unknown and unmanaged. Abstract (Spanish): Restricciones Actuales y Directrices Futuras en la Estimacion de la Coextincion Resumen: La coextincion es un fenomeno poco cuantificado, pero los resultados de modelos recientes sugieren grandes perdidas de biodiversidad local mediante la perdida de especies dependientes cuando los hospederos se extinguen. Hay vacios criticos en la teoria de coextincion, y los delineamos en un marco de referencia para dirigir la investigacion futura hacia estimaciones mas precisas de las tasas de coextincion. Especificamente, las prioridades mas criticas incluyen la obtencion de datos mas precisos de los hospederos, incluyendo el estatus de amenaza de las especie hospedera; obtencion de datos sobre el uso de hospederos por especies dependientes en una amplia gama de localidades, habitats y amplitud tanto de hospederos como dependientes; desarrollo de modelos que incorporen correlaciones de extinciones no aleatorias de hospederos y dependientes, como la filogenia y atributos que incrementan la susceptibilidad a la extincion; y determinar si los dependientes se pierden antes que sus hospederos y consecuentemente ajustar los modelos. Sin el desarrollo sinergico de mejores datos empiricos y modelos mas realistas para estimar el numero de especies coamenazadas y las tasas de coextincion, la contribucion de coextincion a las declinaciones globales de biodiversidad permanecera desconocida y no podra ser manejada. Author Affiliation: (*)School of Botany, University of Melbourne, Parkville, VIC 3010, Australia ([dagger])Western Australian Department of Environment & Conservation, P.O. Box 10173, Kalgoorlie, WA 6430, Australia ([double dagger])NSW National Parks & Wildlife Service, P.O. Box 1967, Hurstville, NSW 2220, Australia (s.)Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia Article History: Paper submitted April 6, 2009; revised manuscript accepted August 17, 2009. Article note: ([dagger][dagger]) email mmoir@unimelb.edu.au