Naturalness and principle pluralism in conservation.

The concept of naturalness in biodiversity conservation remains polysemic, hampering decision-making. Although some conservationists claim ecosystem naturalness should be primarily determined by composition (integrity), others argue it should be determined by the extent of freedom from anthropogenic influence (autonomy). Problems arise when deciding how to treat affected ecosystems. Although the integrity school promotes benchmark-based active restoration, the autonomy school advocates a hands-off policy, making these 2 approaches contradictory. Moreover, expected global changes have promoted advocacy for ecosystem resilience, further complicating the debate. We argue that autonomy, integrity, and resilience are all morally valid. The conflict between them is contained by recognizing that full naturalness is an unattainable goal; restoration and rewilding processes are not an act of curation, but a contrary-to-duty obligation; principle pluralism can accommodate integrity, resilience, and autonomy as pro tanto principles in a case-specific approach; and naturalness, as an overarching value, gives unity to the plurality of principles.

Naturalidad y pluralismo de principios en conservación Resumen El concepto de naturalidad en la conservación de biodiversidad continúa polisémico, lo cual limita la toma de decisiones. Mientras algunos conservacionistas afirman que la naturalidad de los ecosistemas debe ser determinada primariamente por la composición (integridad), otros argumentan que debe ser determinada por la extensión de libertad de la influencia antropogénica (autonomía).Cuando se decide cómo tratar ecosistemas afectados surgen problemas. Mientras la corriente de integridad promueve restauración activa a partir de un punto de referencia, la corriente de autonomía defiende políticas de no intervención, dos enfoques contradictorios. Además, los cambios globales esperados han promovido propugnar por la resiliencia ecosistémica, lo cual complica el debate aún más. Argumentamos que tanto la autonomía, la integridad y la resiliencia son moralmente válidas. El conflicto entre ellas es atajado mediante el reconocimiento de la naturalidad total es una meta inalcanzable; los procesos de restauración y resilvestración no son un acto de curación, sino una obligación contraria al deber; el pluralismo de principios puede acomodar a la integridad, la resiliencia y la autonomía como principios pro tanto en un caso específico; y la naturalidad, como un valor general, proporciona unidad a la pluralidad de principios.

Long-term reevaluation of spatially explicit models as a means for adaptive wildlife management.

We evaluated a 20-yr-old spatially explicit model (SEM) that predicted the spatial expansion of reintroduced Persian fallow deer in northern Israel. Using the current distribution of the deer and based on multi-model inference we assessed the accuracy of the SEM's prediction and what other factors affected the population's current distribution. If the SEM's projection was still valid, the leading model in the multi-model inference would include only the SEM's projection as an explanatory variable with a good fit. Different leading models would reveal key variables overlooked when the SEM was constructed or changes in the landscape unforeseen at the time, thus assisting adaptive management and decision-making. We assessed deer presence from camera trap encounter counts analyzed using N-mixture models. Models included various combinations of seven predictors: the 20-yr predictions of an SEM developed during the initial phases of the reintroduction, three key landscape characteristics on which the SEM was originally based but updated to reflect current conditions, distance from the release site, elevation, and the distribution of gray wolves (a predator that was absent from the area when the SEM was developed). Competing models were ranked by Akaike information criterion (AIC). Wolf distribution was the key predictor explaining the current deer distribution, appearing in all three leading models (∆AIC < 2.0) and carrying 71% of the AIC weight (coefficient = -14.86 ± 5.6 [mean ± SE]). Of these three models, the SEM 20-yr prediction appeared in two, but explained only a fraction of the variance (coefficient = 0.001 ± 0.08). The contribution of all other predictors was negligible. While the SEM failed to accurately predict the 20-yr deer distribution, the divergence between its projection and reality pointed to the probable cause (wolves) of this discrepancy. The inclusion of the SEM prediction in the leading models indicates that had the wolves not spread to the study area, the predictions would still have merit suggesting that long-term SEMs can potentially be robust. Long-term reevaluation of SEMs can be beneficial even if model projections fail, as the process can uncover the specific factors driving this failure, supporting adaptive management procedures.

Invisible barriers: anthropogenic impacts on inter- and intra-specific interactions as drivers of landscape-independent fragmentation.

Anthropogenically induced fragmentation constitutes a major threat to biodiversity. Presently, conservation research and actions focus predominantly on fragmentation caused directly by physical transformation of the landscape (e.g. deforestation, agriculture, urbanization, roads, etc.). While there is no doubt that landscape features play a key role in fragmenting populations or enhancing connectivity, fragmentation may also come about by processes other than the transformation of the landscape and which may not be readily visible. Such landscape-independent fragmentation (LIF) usually comes about when anthropogenic disturbance alters the inter- and intra-specific interactions among and within species. LIF and its drivers have received little attention in the scientific literature and in the management of wildlife populations. We discuss three major classes of LIF processes and their relevance for the conservation and management of species and habitats: (i) interspecific dispersal dependency, in which populations of species that rely on other species for transport and propagation become fragmented as the transporting species declines; (ii) interspecific avoidance induction, where species are excluded from habitats and corridors owing to interspecific interactions resulting from anthropogenically induced changes in community structure (e.g. exclusions by increased predation pressure); and (iii) intraspecific behavioural divergence, where populations become segregated owing to anthropogenically induced behavioural differentiation among them. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.

The crucial but underrepresented role of philosophy in conservation science curricula.

Article impact statement: Normative scientists must be trained in current thinking of the philosophy that underlies their fields, an issue not fully realized in conservation.

Revealing life-history traits by contrasting genetic estimations with predictions of effective population size.

Effective population size, a central concept in conservation biology, is now routinely estimated from genetic surveys and can also be theoretically predicted from demographic, life-history, and mating-system data. By evaluating the consistency of theoretical predictions with empirically estimated effective size, insights can be gained regarding life-history characteristics and the relative impact of different life-history traits on genetic drift. These insights can be used to design and inform management strategies aimed at increasing effective population size. We demonstrated this approach by addressing the conservation of a reintroduced population of Asiatic wild ass (Equus hemionus). We estimated the variance effective size (Nev ) from genetic data (N ev =24.3) and formulated predictions for the impacts on Nev of demography, polygyny, female variance in lifetime reproductive success (RS), and heritability of female RS. By contrasting the genetic estimation with theoretical predictions, we found that polygyny was the strongest factor affecting genetic drift because only when accounting for polygyny were predictions consistent with the genetically measured Nev . The comparison of effective-size estimation and predictions indicated that 10.6% of the males mated per generation when heritability of female RS was unaccounted for (polygyny responsible for 81% decrease in Nev ) and 19.5% mated when female RS was accounted for (polygyny responsible for 67% decrease in Nev ). Heritability of female RS also affected Nev ; hf2=0.91 (heritability responsible for 41% decrease in Nev ). The low effective size is of concern, and we suggest that management actions focus on factors identified as strongly affecting Nev, namely, increasing the availability of artificial water sources to increase number of dominant males contributing to the gene pool. This approach, evaluating life-history hypotheses in light of their impact on effective population size, and contrasting predictions with genetic measurements, is a general, applicable strategy that can be used to inform conservation practice.

Zebra migration strategies and anthrax in Etosha National Park, Namibia.

Partial seasonal migration is ubiquitous in many species. We documented this phenomenon in plains zebra (Equus burchelli) in Etosha National Park, Namibia (ENP), and provided a cost-benefit analysis as it relates to the spatial distribution of water, vegetation and endemic anthrax. This analysis draws upon two years of ENP zebra movement data that reveal two sub-populations: migrators and non-migrators. Migrators are shown to be behaviorally dominant in the way they utilize space and use water holes. We raise the possibility that the co-existence of these two groups reflects an evolutionary process, and the size of each group maintains evolutionary equilibrium.

Inferring detailed space use from movement paths: A unifying, residence time-based framework.

The residence time is the amount of time spent within a predefined circle surrounding each point along the movement path of an animal, reflecting its response to resource availability/quality. Two main residence time-based methods exist in the literature: (1) The variance of residence times along the path plotted against the radius of the circle was suggested to indicate the scale at which the animal perceives its resources; and (2) segments of the path with homogeneous residence times were suggested to indicate distinct behavioral modes, at a certain scale. Here, we modify and integrate these two methods to one framework with two steps of analysis: (1) identifying several distinct, nested scales of area-restricted search (ARS), providing an indication of how animals view complex resource landscapes, and also the resolutions at which the analysis should proceed; and (2) identifying places which the animal revisits multiple times and performs ARS; for these, we extract two scale-dependent statistical measures-the mean visit duration and the number of revisits in each place. The association between these measures is suggested as a signature of how animals utilize different habitats or resource types. The framework is validated through computer simulations combining different movement strategies and resource maps. We suggest that the framework provides information that is especially relevant when interpreting movement data in light of optimal behavior models, and which would have remained uncovered by either coarser or finer analyses.

Research Priorities from Animal Behaviour for Maximising Conservation Progress.

Poor communication between academic researchers and wildlife managers limits conservation progress and innovation. As a result, input from overlapping fields, such as animal behaviour, is underused in conservation management despite its demonstrated utility as a conservation tool and countless papers advocating its use. Communication and collaboration across these two disciplines are unlikely to improve without clearly identified management needs and demonstrable impacts of behavioural-based conservation management. To facilitate this process, a team of wildlife managers and animal behaviour researchers conducted a research prioritisation exercise, identifying 50 key questions that have great potential to resolve critical conservation and management problems. The resulting agenda highlights the diversity and extent of advances that both fields could achieve through collaboration.

Determinants of emigration and their impact on survival during dispersal in fox and jackal populations.

Animals disperse in response to poor resource conditions as a strategy of escaping harsh competition and stress, but may also disperse under good resource conditions, as these provide better chances of surviving dispersal and gaining fitness benefits such as avoiding kin competition and inbreeding. Individual traits should mediate the effect of resources, yielding a complex condition-dependent dispersal response. We investigated how experimental food reductions in a food-rich environment around poultry-growing villages interact with individual-traits (age, gender, body-mass) in two sympatric canids, red foxes and golden jackals, to jointly affect emigration propensity and survival during dispersal. Sub-adult foxes emigrated more frequently from the food-rich habitat than from the pristine, food-limited habitat, while adult foxes showed the opposite trend. During dispersal, adults exhibited lower survival while sub-adults did not experience additional mortality costs. Although fox mortality rates increased in response to food reduction, dispersal remained unchanged, while jackals showed strong dispersal response in two of the three repetitions. Jackal survival under food reduction was lowest for the dispersing individuals. While resources are an important dispersal determinant, different age classes and species experience the same resource environment differently and consequently have different motivations, yielding different dispersal responses and consequences.

A systematic survey of the integration of animal behavior into conservation.

The role of behavioral ecology in improving wildlife conservation and management has been the subject of much recent debate. We sought to answer 2 foundational questions about the current use of behavioral knowledge in conservation: To what extent is behavioral knowledge used in wildlife conservation and management, and how does the use of animal behavior differ among conservation fields in both frequency and types of use? We searched the literature for intersections between key fields of animal behavior and conservation and created a systematic heat map (i.e., graphical representation of data where values are represented as colors) to visualize relative efforts. Some behaviors, such as dispersal and foraging, were commonly considered (mean [SE] of 1147.38 [353.11] and 439.44 [108.85] papers per cell, respectively). In contrast, other behaviors, such as learning, social, and antipredatory behaviors were rarely considered (mean [SE] of 33.88 [7.62], 44.81 [10.65], and 22.69 [6.37] papers per cell, respectively). In many cases, awareness of the importance of behavior did not translate into applicable management tools. Our results challenge previous suggestions that there is little association between the fields of behavioral ecology and conservation and reveals tremendous variation in the use of different behaviors in conservation. We recommend that researchers focus on examining underutilized intersections of behavior and conservation themes for which preliminary work shows a potential for improving conservation and management, translating behavioral theory into applicable and testable predictions, and creating systematic reviews to summarize the behavioral evidence within the behavior-conservation intersections for which many studies exist.

Everybody loses: intraspecific competition induces tragedy of the commons in Allenby's gerbils.

Interference competition may lead to a tragedy of the commons in which individuals driven by self-interest reduce the fitness of the entire group. We investigated this hypothesis in Allenby's gerbils, Gerbillus andersoni allenbyi, by comparing foraging behaviors of single vs. pairs of gerbils. We recorded strong interference competition within the foraging pairs. Competition reduced the amount of time the gerbils spent foraging, as well as foraging efficiency since part of the foragers' attention was directed toward detecting competitors (apparent predation risk). Single gerbils harvested significantly more food than the combined efforts of two gerbils foraging together. Competition reduced the success of both individuals within a pair by more than 50%, making this a case of the tragedy of the commons where each individual's investment in competition reduces the success of all individuals within the group, including its own. Despite their great costs, competitive behaviors will be selected for as long as one individual achieves higher fitness than the other. In nature, interspecific interactions, such as predation risk, may act to reduce and regulate the deleterious effects of intraspecific competition.

The exploration-exploitation dilemma: a multidisciplinary framework.

The trade-off between the need to obtain new knowledge and the need to use that knowledge to improve performance is one of the most basic trade-offs in nature, and optimal performance usually requires some balance between exploratory and exploitative behaviors. Researchers in many disciplines have been searching for the optimal solution to this dilemma. Here we present a novel model in which the exploration strategy itself is dynamic and varies with time in order to optimize a definite goal, such as the acquisition of energy, money, or prestige. Our model produced four very distinct phases: Knowledge establishment, Knowledge accumulation, Knowledge maintenance, and Knowledge exploitation, giving rise to a multidisciplinary framework that applies equally to humans, animals, and organizations. The framework can be used to explain a multitude of phenomena in various disciplines, such as the movement of animals in novel landscapes, the most efficient resource allocation for a start-up company, or the effects of old age on knowledge acquisition in humans.

Genetic diversity of the Eurasian Otter (Lutra lutra) population in Israel.

The Israeli population of Eurasian otter (Lutra lutra) marks the Palearctic southern boundary of the species' distribution in the Levant. During the 20th century, the otter population in Israel experienced a dramatic decline due to anthropogenic habitat alterations. Currently, the otter population in Israel is estimated at about 100 individuals and defined as "Critically Endangered". The aim of this research was to characterize the Israeli otter population in order to determine its genetic diversity and fragmentation state for conservation purposes. Monitoring spraint sites during 2000-2011 along active and historic otter distribution regions indicate both stable and unstable otter subpopulations, mainly along the Jordan River. Four otter subpopulations, representing 57 individuals, were characterized by 12 microsatellites, previously used to characterize the European otter populations. The genetic results indicated three subpopulations correlating with three geographical regions: the Hula Valley, Sea of Galilee, and the Harod Valley. A moderate genetic diversity (F (st) = 0.087-0.123) was found among the subpopulations, suggesting sporadic interactions between individuals from distinct geographical locations along the Jordan Rift Valley. The Israeli otter population was found to be very small, demographically remote and genetically distinct, harboring unique alleles absent from the studied European populations. Therefore, immediate conservation actions are recommended to prevent the deterioration of the isolated, unique, and critically endangered otter population in Israel.

Effectiveness of multiple release sites in reintroduction of Persian fallow deer.

Releasing animals in more than one location may increase or decrease the probability of success of a reintroduction project, yet the question of how many release sites to use has received little attention. We used empirical data from the reintroduction program of the Persian fallow deer (Dama mesopotamica) (Galilee region in northern Israel) in an individual-based spatially explicit simulation model to assess the effects of releasing deer from multiple sites. We examined whether multiple release sites increase reintroduction success, and if so, whether the optimal number of sites for a given scenario can be determined and whether the outcome differs if animals are released alternately (i.e., the location of the release alternates yearly between sites) or consecutively (i.e., one release site is used for several years, then another is used, and so forth). We selected 8 potential release sites in addition to the original site and simulated the release of 180 individuals at a rate of 10 individuals per year in different combinations of the original site and 1-4 additional sites. In our model, releasing animals into the wild at multiple sites produced higher population growth and greater spatial expansion than releasing animals at only one site and a consecutive-release approach was superior to an alternate-release approach. We suggest that through the use of simulation modeling that is based on empirical data from previous releases, managers can make better-informed decisions regarding the use of multiple release sites and greatly improve the probability of reintroduction success.

Does interspecific competition drive patterns of habitat use in desert bat communities?

Bodies of water are a key foraging habitat for insectivorous bats. Since water is a scarce and limiting resource in arid environments, bodies of open water may have a structuring effect on desert bat communities, resulting in temporal or spatial partitioning of bat activity. Using acoustic monitoring, we studied the spatial and temporal activity patterns of insectivorous bats over desert ponds, and hypothesised that sympatric bat species partition the foraging space above ponds based on interspecific competitive interactions. We used indirect measures of competition (niche overlap and competition coefficients from the regression method) and tested for differences in pond habitat selection and peak activity time over ponds. We examined the effect of changes in the activity of bat species on their potential competitors. We found that interspecific competition affects bat community structure and activity patterns. Competing species partitioned their use of ponds spatially, whereby each species was associated with different pond size and hydroperiod (the number of months a pond holds water) categories, as well as temporally, whereby their activity peaked at different hours of the night. The drying out of temporary ponds increased temporal partitioning over permanent ponds. Differences in the activity of species over ponds in response to the presence or absence of their competitors lend further support to the role of interspecific competition in structuring desert bat communities. We suggest that habitat use and night activity pattern of insectivorous bats in arid environments reflect the trade-offs between selection of preferred pond type or activity time and constraints posed by competitive interactions.

Ecological trap for desert lizards caused by anthropogenic changes in habitat structure that favor predator activity.

Anthropogenic habitat perturbation is a major cause of population decline. A standard practice managers use to protect populations is to leave portions of natural habitat intact. We describe a case study in which, despite the use of this practice, the critically endangered lizard Acanthodactylus beershebensis was locally extirpated from both manipulated and natural patches within a mosaic landscape of an afforestation project. We hypothesized that increased structural complexity in planted patches favors avian predator activity and makes these patches less suitable for lizards due to a heightened risk of predation. Spatial rarity of natural perches (e.g., trees) in arid scrublands may hinder the ability of desert lizards to associate perches with low-quality habitat, turning planted patches into ecological traps for such species. We erected artificial trees in a structurally simple arid habitat (similar to the way trees were planted in the afforestation project) and compared lizard population dynamics in plots with these structures and without. Survival of lizards in the plots with artificial trees was lower than survival in plots without artificial trees. Hatchlings dispersed into plots with artificial trees in a manner that indicated they perceived the quality of these plots as similar to the surrounding, unmanipulated landscape. Our results showed that local anthropogenic changes in habitat structure that seem relatively harmless may have a considerable negative effect beyond the immediate area of the perturbation because the disturbed habitat may become an ecological trap.

Behavioral changes, stress, and survival following reintroduction of Persian fallow deer from two breeding facilities.

Reintroductions often rely on captive-raised, naïve animals that have not been exposed to the various threats present in natural environments. Wild animals entering new areas are timid and invest much time and effort in antipredator behavior. On the other hand, captive animals reared in predator-free conditions and in close proximity to humans may initially lack this tendency, but can reacquire some antipredator behavior over time. We monitored the changes in antipredator-related behaviors of 16 radio-collared Persian fallow deer (Dama mesopotamica) reintroduced to the Soreq Valley in Israel from 2 breeding facilities: one heavily visited by the public (The Biblical Zoo of Jerusalem, Israel) and the other with reduced human presence (Hai-Bar Carmel, Israel). We monitored each individual for up to 200 days after release, focusing on flush and flight distance, flight mode (running or walking), and use of cover. In addition, we compared fecal corticosterone (a stress-related hormone) from samples collected from known animals in the wild to samples collected in the breeding facilities. Reintroduced individuals from both origins exhibit increased flush distance over time; flush and flight distances were larger in individuals from Hai-Bar; use of cover increased with time, but was greater in Hai-Bar Carmel animals; corticosterone levels were significantly higher in fecal samples from reintroduced animals than in samples from captive animals; and Hai-Bar Carmel animals had an 80% survival rate over the 200 days, whereas no animals from the Biblical Zoo of Jerusalem survived. Reintroduced Persian fallow deer reacquired antipredator behaviors after the release, but the process was slow (months) and differences between conditions at the breeding facilities that were seemingly benign (e.g., number of visitors and other human related activities) influenced this process and consequently affected the success of the reintroduction. Captive breeding facilities for the purpose of reintroduction should minimize anthropogenic disturbances.

A framework for generating and analyzing movement paths on ecological landscapes.

The movement paths of individuals over landscapes are basically represented by sequences of points (x(i), y(i)) occurring at times t(i). Theoretically, these points can be viewed as being generated by stochastic processes that in the simplest cases are Gaussian random walks on featureless landscapes. Generalizations have been made of walks that (i) take place on landscapes with features, (ii) have correlated distributions of velocity and direction of movement in each time interval, (iii) are Lévy processes in which distance or waiting-time (time-between steps) distributions have infinite moments, or (iv) have paths bounded in space and time. We begin by demonstrating that rather mild truncations of fat-tailed step-size distributions have a dramatic effect on dispersion of organisms, where such truncations naturally arise in real walks of organisms bounded by space and, more generally, influenced by the interactions of physiological, behavioral, and ecological factors with landscape features. These generalizations permit not only increased realism and hence greater accuracy in constructing movement pathways, but also provide a biogeographically detailed epistemological framework for interpreting movement patterns in all organisms, whether tossed in the wind or willfully driven. We illustrate the utility of our framework by demonstrating how fission-fusion herding behavior arises among individuals endeavoring to satisfy both nutritional and safety demands in heterogeneous environments. We conclude with a brief discussion of potential methods that can be used to solve the inverse problem of identifying putative causal factors driving movement behavior on known landscapes, leaving details to references in the literature.

A movement ecology paradigm for unifying organismal movement research.

Movement of individual organisms is fundamental to life, quilting our planet in a rich tapestry of phenomena with diverse implications for ecosystems and humans. Movement research is both plentiful and insightful, and recent methodological advances facilitate obtaining a detailed view of individual movement. Yet, we lack a general unifying paradigm, derived from first principles, which can place movement studies within a common context and advance the development of a mature scientific discipline. This introductory article to the Movement Ecology Special Feature proposes a paradigm that integrates conceptual, theoretical, methodological, and empirical frameworks for studying movement of all organisms, from microbes to trees to elephants. We introduce a conceptual framework depicting the interplay among four basic mechanistic components of organismal movement: the internal state (why move?), motion (how to move?), and navigation (when and where to move?) capacities of the individual and the external factors affecting movement. We demonstrate how the proposed framework aids the study of various taxa and movement types; promotes the formulation of hypotheses about movement; and complements existing biomechanical, cognitive, random, and optimality paradigms of movement. The proposed framework integrates eclectic research on movement into a structured paradigm and aims at providing a basis for hypothesis generation and a vehicle facilitating the understanding of the causes, mechanisms, and spatiotemporal patterns of movement and their role in various ecological and evolutionary processes. "Now we must consider in general the common reason for moving with any movement whatever." (Aristotle, De Motu Animalium, 4th century B.C.).