Markov models of territory occupancy: Implications for the management and conservation of competing species

Markov chains have been frequently used in community ecology to model successional changes, but little attention has been paid to its application in population ecology as a tool to explore the outcomes of species interactions. Markov models can be regarded as >null models> that provide predicted values under a no-change scenario against which the consequences of changes in variables of interest can be assessed. Here we explore Markov chains' potential to project population trends of competing species and derive sensible management strategies. To do that we use six years of field data on territory occupancy and turn-over of two competing top predators in a Mediterranean landscape: the golden and Bonelli's eagles. The results suggest that long-term coexistence of both species in the study area is likely, with the main limitation for their coexistence being the difficulties Bonelli's eagles have in colonising new territories that become available. To avoid future declines in the population of Bonelli's eagle, it is important to take into account that the positive effects of conservation strategies focused on encouraging colonization (e.g. decreasing disperser mortality) are likely to be larger than those focused on avoiding territory abandonment (e.g. decreasing adult mortality). Markov chains are likely to be useful to evaluate the relative merit of alternative management options in other territorial species when patterns of territory occupancy are the only reliable data available, as often happens with large predators. © 2008 Springer Science+Business Media B.V.Peer Reviewe

Living on the Edge: Assessing the Extinction Risk of Critically Endangered Bonelli’s Eagle in Italy

Background: The population of Bonelli’s eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings: We incorporated the most updated demographic information available to assess the extinction risk of endangered Bonelli’s eagle in Italy through a Population Viability Analysis. Using perturbation analyses (sensitivity and elasticity), and a combination of demographic data obtained from an assortment of independent methods, we evaluated which demographic parameters have more influence on the population’s fate. We also simulated different scenarios to explore the effects of possible management actions. Our results showed that under the current conditions, Bonelli’s eagle is expected to become extinct in Italy in less than 50 years. Stand-alone juvenile mortality was the most critical demographic parameter with the strongest influence on population persistence with respect to other demographic parameters. Measures aimed at either decreasing juvenile mortality, adult mortality or decreasing both juvenile and adult mortality resulted in equivalent net positive effects on population persistence (population growth rate l.1). In contrast, changes aimed at increasing breeding success had limited positive effects on demographic trends. Conclusions/Significance: Our PVA provides essential information to direct the decision-making process and exposes gaps in our previous knowledge. To ensure the long-term persistence of the species in Italy, measures are urgently needed to decrease both adult mortality due to poaching and juvenile mortality due to nest plundering, the top ranking mortality causes.PLL is supported by a “Juan de la Cierva” postdoctoral grant of the Spanish Ministry of Economy and Competitiveness (reference JCI-2011–09588)

Anales de Edafología y Agrobiología Tomo 33 Número 9-10

Estudio del equilibrio nutritivo en cultivos de chirimoyo (Annona cherimolia), por César González O., Miguel Fuentes y Soledad Díaz.-- Resistencia a la desecación del tejido foliar y cierre de estomas en alfalfa (M edicago sativa L.) y trébol blanco (Trijolium repens L.) con relación al déficit agua, por M. Sánchez-Díaz y M. Sánchez-Marín.-- Determinación del calor isostérico y consideraciones sobre el mecanismo de la adsorción de fosfato por óxidos de hierro, por L. Madrid, F. Cabrera, P. de Arambarri y E. Díaz.-- Studies on sodium-calcium exchange equilibria. II. In Egyptian soils, by M. H. Nafady.-- Indices nutritivos en manzano (var. R. Delicious), por C. González, O. M. Rodríguez M., J. Solé D. y A. Wylie W.-- Caracteres de los suelos de las zonas citrícolas del valle de Murcia (España), por J. A. Sánchez F., F. Artes y J. López-Tarruella.-- Estudio micromorfológico de suelos desarrollados sobre andesitas en Andalucía oriental, por J. Aguilar y M. Delgado.-- Estudio edafológico de los relieves próximos a la vega de Motril, por J. Aguilar, Ruiz, A. Monge Ureña y C. Sierra Ruiz de la F.-- Consideraciones experimentales sobre el análisis de boro en plantas, por A. León, F.J. López-Andréu, F. Romojaro y C. Alcaraz.-- Efectos de la aplicación conjunta de fertilizantes químicos y microbianos (Azotobaeter Fosjobaeterias) en cultivos enarenados de tomate, por R. Azcón, M. Gómez y J. M. Barea.-- Formas de calcio en suelos del piso tropical de Barbacoas, Colombia, por G. Hugo Eraso, L. Federman Ortiz y O. Hernán Burbano.-- Compuestos íenólicos en Eriea vagans L., por J. Arinés, J. L. G. Mantilla y E. Vieitiz.-- Determinación de glúcidos en plantas por fotocolorimetría. Estudio comparativo de métodos clásicos y automáticos, por C. Cadahía y M. T. Piñeiro.-- Notas. Nombramiento de Consejeros Adjuntos del Patronato Alonso de Herrera.-- Nombramiento y cese de Vocales de la Junta de Gobierno del Patronato Alonso de Herrera.--Fallo de los Premios Alonso de Herrera y Antonio José de Cavanilles.-- Propuesta del Instituto de Alimentación y Productividad Animal sobre nombramiento de Vicedirector del mismo.-- Congresos y Reuniones internacionales.-- Creación de la Comisión Conjunta de Investigación Agraria de los Ministerios de Educación y Ciencia y de Agricultura.-- Restauración y adecuación del Jardín Botánico de Madrid.-- III Reunión Nacional de Centros de Investigación Ganadera Tribunales.-- Clausura del XI Curso Internacional de Edafología y Biología Vegetal.-- 7th International Colloquium on Plant Analysis and Fertilizer Problems.-- X Congreso Internacional de Ciencia del Suelo.-- Clausura del IV Congreso de Ciencia y Tecnología de Alimentos.-- 50th Anniversary Meeting of the British Society for Experimental Biología.-- XXIX Symposium on Symbiosis, Society for Experimental Biología.-- IV Reunión de la Sociedad Español de Microscopía Electrónica.-- Subvención de la Fundación Barrie de la Maza a la Misión Biológica de Galicia.-- Conferencia.-- Los universitarios y la defensa de la naturaleza.-- Seminario, sobre Tipos diferentes de costras calizas y su distribución regional.-- BibliografíaPeer reviewed2019-08.- CopyBook.- Libnova.- Biblioteca ICA

¿Son suficientes para la conservación las ZEPAs y las ZECs?: el caso del Aguila perdicera en el área mediterránea

The Bonelli’s eagle (BE) is considered by the European Union as a high-priority species for conservation in the Valencian Community (East of Spain). However, in 2006 the European Union opened a legal procedure against the Spanish Kingdom, accused of lacking of an adequate network of special protected areas (SPAs) to preserve the BE in the region. Here we evaluate whether important bird areas (IBAs) and SPAs network is enough to preserve this species, on the basis of a thorough analysis of habitat preferences. A GAP analysis is performed to conduct a revision of current SPAs and BirdLife proposed IBAs. Our results suggest that the current network of SPAs becomes insufficient to protect the BE. The IBAs network, although improves the current network of SPAs, increasing the percentage of BE potential habitat included, also results inadequate. We propose a new SPAs network according to the potential suitable habitat for the species. Given the trade-off between financial investment and the conservation of biodiversity, we propose to maximize the surface of potential habitat included in the protected network minimizing the surface of the region that would be necessary to protect, thus avoiding an unnecessary expense and otherwise unrealistic results.Fundación Terra Natur