Selección de especies y efecto del ciervo (Cervus elaphus L.) sobre arbustedos y matorrales de los Montes de Toledo, España central

Agroforestry systems (mosaics of woodlands, rangelands and croplands) managed for red deer rearing and hunting constitute a profitable and increasing form of land usage in Mediterranean Spain since the 1960s. As a consequence, stocking rates have increased dramatically and are now frequently over 50 individuals/km2. That situation has created a new problem of sustainability for that new type of agroforestry systems. This paper analyses the selection of woody species by red deer and the effect of that species on Mediterranean shrublands at the Montes de Toledo range in central Spain. Selection indexes were measured for 33 woody species by comparing percentages of utilization (browsing) with percentages of availability. Phillyrea angustifolia, Arbutus unedo and Quercus faginea showed the highest selection indexes while Thymus mastichina, Daphne gnidium and Pinus pinea showed the lowests ones. Food preferences showed no significant variation with different red deer stocking rates. The effect of red deer stocking rates around 35 individuals/km2 on woodlands and shrublands seems to be over the sustainability level even though sown pastures and croplands are available for red deer populations within the study area.Los sistemas agroforestales (mosaicos de bosques, arbustedos, matorrales, pastos herbáceos y cultivos) dedicados a la caza del ciervo constituyen una forma rentable y creciente de uso territorial en la España mediterránea desde la década de 1960. Como consecuencia, las cargas cinegéticas han aumentado mucho y sobrepasan con frecuencia los 50 individuos/km2. Ello origina un nuevo problema de sustentabilidad para esos nuevos sistemas agroforestales. Este trabajo analiza la selección de especies leñosas por el ciervo y el efecto de sus poblaciones sobre arbustedos y matorrales de los Montes de Toledo. Se obtuvieron índices de selección para 33 especies leñosas comparando sus porcentajes de utilización (ramoneo) con los de disponibilidad. Phillyrea angustifolia, Arbutus unedo y Quercus faginea presentaron los máximos índices mientras que Thymus mastichina, Daphne gnidium y Pinus pinea exhibieron los más bajos. Las preferencias alimenticias no varíaron significativamente al hacerlo las cargas cinegéticas. El efecto de una carga del orden de 35 ciervos/km2 parece superar el límite de sustentabilidad, incluso teniendo en cuenta que en el área de estudio existen pastos sembrados y cultivos disponibles para los ciervos

Multimethod, multistate Bayesian hierarchical modeling approach for use in regional monitoring of wolves

[EN]: In many cases, the first step in large-carnivore management is to obtain objective, reliable, and cost-effective estimates of population parameters through procedures that are reproducible over time. However, monitoring predators over large areas is difficult, and the data have a high level of uncertainty. We devised a practical multimethod and multistate modeling approach based on Bayesian hierarchical-site-occupancy models that combined multiple survey methods to estimate different population states for use in monitoring large predators at a regional scale. We used wolves (Canis lupus) as our model species and generated reliable estimates of the number of sites with wolf reproduction (presence of pups). We used 2 wolf data sets from Spain (Western Galicia in 2013 and Asturias in 2004) to test the approach. Based on howling surveys, the naïve estimation (i.e., estimate based only on observations) of the number of sites with reproduction was 9 and 25 sites in Western Galicia and Asturias, respectively. Our model showed 33.4 (SD 9.6) and 34.4 (3.9) sites with wolf reproduction, respectively. The number of occupied sites with wolf reproduction was 0.67 (SD 0.19) and 0.76 (0.11), respectively. This approach can be used to design more cost-effective monitoring programs (i.e., to define the sampling effort needed per site). Our approach should inspire well-coordinated surveys across multiple administrative borders and populations and lead to improved decision making for management of large carnivores on a landscape level. The use of this Bayesian framework provides a simple way to visualize the degree of uncertainty around population-parameter estimates and thus provides managers and stakeholders an intuitive approach to interpreting monitoring results. Our approach can be widely applied to large spatial scales in wildlife monitoring where detection probabilities differ between population states and where several methods are being used to estimate different population parameters.J.V.L.B. was supported by a Juan de la Cierva research contract (JCI-2012-13066) from the Spanish Ministry of Economy and Competitiveness.Peer Reviewe

Monitoring wolf occupancy and reproductive groups at regional level

Trabajo presentado al IV Congresso Ibérico do Lobo, celebrado en la Escola Superior Agrária do Instituto Politécnico de Castelo Branco (Portugal) del 27 al 30 de Octubre de 2016.Peer Reviewe

Estimando la ocupación y los grupos reproductores de lobo a escala regional

Trabajo presentado al XII Congreso de la Sociedad Española para la Conservación y Estudio de los Mamíferos (SECEM), celebrado en Burgos del 4 al 7 de diciembre de 2015.La gestión de especies exige el uso de sistemas de seguimiento de poblaciones estandarizados, objetivos y replicables. En el caso del lobo, ello resulta singularmente complejo a escala regional. Diferentes planes de gestión y conservación de la especie se basan en información sobre la distribución de la especie y el número de grupos reproductores. En esta presentación se presenta una metodología de seguimiento del lobo a escala regional que considerando la detectabilidad, combina: i) la estima de la ocupación espacial basada en un modelo de sitio-ocupación incorporando la correlación espacial de la presencia del lobo (con modelos condicionales autoregresivos) y utilizando covariables (p.ej. altitud, longitud de transecto) para ocupación y detección. En el caso de estudio que se presenta -el lobo en España- se observa una relación significativa y positiva entre la ocupación y la altitud, y entre la longitud del transecto y la probabilidad de detección; ii) una metodología específica para estimar grupos reproductores, también basada en los modelos de sitio-ocupación, que da respuesta a la dificultad de estimar grupos reproductores con las bajas probabilidades de detección en las estaciones de escucha. De manera tradicional, se ha considerado como "segura" la reproducción en los grupos con detección de cachorros en estaciones de escucha o puntos de observación y "probable" para aquellos grupos donde se detectaba una alta acumulación de otros indicios de presencia. Como consecuencia, en la estima de grupos reproductores no se conocía el error asociado al muestreo. Hemos integrado dos metodologías de seguimiento comúnmente utilizadas en la Península Ibérica (búsqueda de indicios y estaciones de escucha) en un marco bayesiano en BUGS, que permite estimar el número de grupos de lobos con y sin reproducción, y las probabilidades asociadas a las metodologías de detección y sus correspondientes errores. El modelo que se presenta aquí se ha testado con simulaciones y con datos reales. Concluimos que su uso permite una estima más precisa, incorpora los niveles de incertidumbre, y posibilita además la planificación previa del muestreo para ajustar los errores de la estima a realizar.Peer reviewe

Population Estimation and Trappability of the European Badger (Meles meles): Implications for Tuberculosis Management.

peer-reviewedEstimates of population size and trappability inform vaccine efficacy modelling and are required for adaptive management during prolonged wildlife vaccination campaigns. We present an analysis of mark-recapture data from a badger vaccine (Bacille Calmette–Gue´ rin) study in Ireland. This study is the largest scale (755 km2) mark-recapture study ever undertaken with this species. The study area was divided into three approximately equal–sized zones, each with similar survey and capture effort. A mean badger population size of 671 (SD: 76) was estimated using a closed-subpopulation model (CSpM) based on data from capturing sessions of the entire area and was consistent with a separate multiplicative model. Minimum number alive estimates calculated from the same data were on average 49–51% smaller than the CSpM estimates, but these are considered severely negatively biased when trappability is low. Population densities derived from the CSpM estimates were 0.82–1.06 badgers km22, and broadly consistent with previous reports for an adjacent area. Mean trappability was estimated to be 34–35% per session across the population. By the fifth capture session, 79% of the adult badgers caught had been marked previously. Multivariable modelling suggested significant differences in badger trappability depending on zone, season and age-class. There were more putatively trap-wary badgers identified in the population than trap-happy badgers, but wariness was not related to individual’s sex, zone or season of capture. Live-trapping efficacy can vary significantly amongst sites, seasons, age, or personality, hence monitoring of trappability is recommended as part of an adaptive management regime during large–scale wildlife vaccination programs to counter biases and to improve efficiencies.Department of Agriculture, Food and the MarineTeagasc Walsh Fellowship Programm

La restauración del lince puede reducir la abundancia de otros depredadores

Resumen del trabajo presentado al XIV Congreso de la Sociedad Española para la Conservación y Estudio de los Mamíferos (SECEM), celebrado en Jaca (Huesca) del 5 al 8 de diciembre de 2019.Peer reviewe

Restoring apex predators can reduce mesopredator abundances

The role that apex predators play in ecosystem functioning, disease regulation and biodiversity maintenance is increasingly debated. However, the positive impacts of their presence in terrestrial ecosystems, particularly in human-dominated landscapes, remain controversial. Limited experimental insights regarding the consequences of apex predator recoveries may be behind such controversy and may also impact on the social acceptability towards the recovery of these species. Using a quasi-experimental design and state-of-the-art density estimates, we show that mesopredator abundances were reduced after the restoration of an apex predator, with evidence of resonating positive impacts on lower trophic levels. Iberian lynx Lynx pardinus reintroduction was followed by the reduction of the abundance of mesocarnivores (red foxes Vulpes vulpes and Egyptian mongooses Herpestes ichneumon by ca. 80%) and the recovery of small game of high socio-economic value (European rabbits Oryctolagus cuniculus and red-legged partridges Alectoris rufa). The observed mesopredator reduction resulted in an estimated 55.6% less rabbit consumption for the entire carnivore guild. Our findings have important implications for the social acceptability of Iberian lynx reintroductions, which crucially depend on the perception of private land owners and managers. Under certain circumstances, restoring apex predators may provide a sustainable and ethically acceptable way to reduce mesopredator abundances.J.J. and J.C.N.A.worked under the project 17MNES021 from the Spanish Ministry forthe Ecological Transition (MITECO), executed by TRAGSATEC S.L.J.V.L.B. was supported by the Ramon & Cajal program (RYC-2015-18932) from the Ministry of Economy, Industry and Competitiveness. The staff of IberLince LIFE Project (LIFE10NAT/ES/570) in Extremadura, and Extremadura Regional Government.Peer reviewe

A poor international standard for trap selectivity threatens carnivore conservation

Unintentional mortality of endangered carnivores due to non-selective trapping is important for conservation and warrants urgent attention. Currently, non-selective traps are being approved and used based on trap selectivity tests conducted according to International Organization for Standardization (ISO) guidelines. We review these guidelines and find them inadequate, because: 1) the ISO definition of selectivity does not account for relative abundance of target and non-target species and does not therefore meaningfully reflect selectivity; 2) the guidelines methodology at best quantifies relative selectivity of one trap against another, which is of limited use unless the control trap is known to have an acceptable level of absolute selectivity for the target species; 3) information on relative trap selectivity cannot simply be extrapolated elsewhere, unless species assemblage and relative species abundances are consistent. We demonstrate that the ISO definition of trap selectivity is only a simple capture proportion and therefore does not represent trap selectivity. ISO guidelines on trap selectivity should be reviewed to reflect particular ecological scenarios and we suggest how this might be done. Policy-makers, practitioners and researchers should interpret scientific results more cautiously. Trap approval decisions should be based on scientific evidence to avoid undermining the conservation of biodiversity