Quantifying dispersal paths in probabilistic habitat networks: a reply to hock and mumby (2015) and an overview of recent developments and applications

Hock and Mumby (2015) describe an approach to quantify dispersal probabilities along paths in networks of habitat patches. This approach basically consists in determining the most probable (most reliable) path for movement between habitat patches by calculating the product of the dispersal probabilities in each link (step) along the paths in the network. Although the paper by Hock and Mumby (2015) has value and includes interesting analyses (see comments in section 7 below), the approach they describe is not new

Influencia de la escala en la configuración del paisaje : mediante un nuevo método de simulación espacial, imágenes de satélite y cartografías temáticas

La creciente preocupación por la evaluación y seguimiento del estado y función de los ecosistemas y paisajes ha dado lugar en los últimos años a un gran desarrollo de los índices de configuración espacial. Éstos son útiles como indicadores ecológicos, al sintetizar y cuantificar aspectos fundamentales de los patrones del paisaje, tales como los relacionados con la fragmentación y la complejidad de las formas de las teselas. Por otro lado, la gran variedad de fuentes de información espacial disponibles actualmente hace que sea cada vez más necesario y frecuente manejar y comparar datos espaciales correspondientes a distintas escalas. Es conocido que la escala influye notablemente en los valores de estos índices espaciales, pero el actual "estado del arte" imposibilita en general realizar comparaciones entre distintas fuentes de información, lo que limita la potencial utilidad de este tipo de análisis de los patrones del paisaje. Para avanzar en el esclarecimiento de estas cuestiones, en esta tesis se realiza un estudio de la influencia de la escala en los índices de configuración del paisaje más detallado y sistemático que en investigaciones anteriores, considerando los tres componentes que definen la escala de los datos cartográficos: la extensión espacial, la unidad mínima cartografiada y la resolución espacial. Para ello se analizan tanto simulaciones espaciales proporcionadas por el nuevo método de conglomerados aleatorios modificados (CAM) como datos categóricos reales derivados de la cartografía CORINE y de imágenes de satélite coetáneas Landsat-TM e IRS-WiFS. El método CAM, que se presenta y describe en esta tesis, permite generar una amplia variedad de simulaciones espaciales en las que se pueden controlar detalladamente los distintos factores que conforman los patrones del paisaje. Por otro lado, los datos reales permiten contrastar y, en su caso, validar las conclusiones obtenidas mediante simulación, proporcionando mayor solidez al análisis realizado. Los resultados y conclusiones originales obtenidos en esta tesis hacen posible conocer el efecto de la escala en la estimación de la fragmentación e irregularidad de las formas de los paisajes. Además, permiten seleccionar aquellos índices más adecuados para la comparación de la configuración de datos espaciales con diferente extensión, resolución o unidad mínima cartografiada

Forest connectivity restoration through reforestation: an integrated methodology for prioritizing agricultural lands and selecting reforestation species

Forest connectivity restoration is a major goal in natural resource planning. Given the high amount of abandoned cultivated lands, setting efficient methods for the reforestation of agricultural lands offers a good opportunity to face this issue. However, reforestations must be carefully planned, which poses two main challenges. In first place, to determine those agricultural lands that, once reforested, would meet more effectively the planning goals. As a further step, in order to grant the success of the activity, it is fairly advisable to select those tree species that are more adapted to each particular environment. Here we intend to give response to both requirements by proposing a sequential and integrated methodology that has been implemented in two Spanish forest districts, which are formed by several landscape types that were previously defined and characterized. Using the software Conefor Sensinode, a powerful tool for quantifying habitat availability that is based on graph theory concepts, we determined the landscapes where forest planning should have connectivity as a major concern and, afterwards, we detected the agricultural patches that would contribute most to enhance connectivity if they were reforested. The subsequent reforestation species assessment was performed within these priority patches. Using penalized logistic regressions we fitted ecological niche models for the Spanish native tree species. The models were trained with species distribution data from the Spanish Forest Map and used climatic and lithological variables as predictors. Model predictions were used to build ordered lists of suitable species for each priority patch. The lists include dominant and non dominant tree species and allow adding biodiversity goals to the reforestation planning. The result of this combined methodology is a map of agricultural patches that would contribute most to uphold forest connectivity if they were reforested and a list of suitable tree species for each patch ordered by occurrence probability. Therefore the proposed methodology may be useful for suitable and efficient forest planning and landscape designing

Mejora de la calidad y conectividad del hábitat forestal del oso pardo en la Cordillera Cantábrica: propuesta metodológica e implicacionesde gestión

Desarrollo de estrategias de gestión forestal que mejoren la calidad del hábitat para el oso pardo cantábrico y la conectividad dentro y entre sus subpoblaciones

Large-scale determinants of diversity across Spanish forest habitats: accounting for model uncertainty in compositional and structural indicators

An integral understanding of forest biodiversity requires the exploration of the many aspects it comprises and of the numerous potential determinants of their distribution. The landscape ecological approach provides a necessary complement to conventional local studies that focus on individual plots or forest ownerships. However, most previous landscape studies used equally-sized cells as units of analysis to identify the factors affecting forest biodiversity distribution. Stratification of the analysis by habitats with a relatively homogeneous forest composition might be more adequate to capture the underlying patterns associated to the formation and development of a particular ensemble of interacting forest species. Here we used a landscape perspective in order to improve our understanding on the influence of large-scale explanatory factors on forest biodiversity indicators in Spanish habitats, covering a wide latitudinal and altitudinal range. We considered six forest biodiversity indicators estimated from more than 30,000 field plots in the Spanish national forest inventory, distributed in 213 forest habitats over 16 Spanish provinces. We explored biodiversity response to various environmental (climate and topography) and landscape configuration (fragmentation and shape complexity) variables through multiple linear regression models (built and assessed through the Akaike Information Criterion). In particular, we took into account the inherent model uncertainty when dealing with a complex and large set of variables, and considered different plausible models and their probability of being the best candidate for the observed data. Our results showed that compositional indicators (species richness and diversity) were mostly explained by environmental factors. Models for structural indicators (standing deadwood and stand complexity) had the worst fits and selection uncertainties, but did show significant associations with some configuration metrics. In general, biodiversity increased in habitats covering wider topographic ranges and comprising forest patches with more complex shapes. Patterns in other relationships varied between indicators (e.g. species richness vs. diversity), or even were opposed (trees vs. shrubs). Our study (1) allowed deepening the understanding of biodiversity patterns in a large set of Spanish forest habitats and (2) highlighted the increasing complexity of identifying common landscape conditions favouring forest biodiversity as the range of analysed biodiversity aspects is widened beyond the more commonly assessed species richness indicators.This work has received financial support from the Ministerio de Ciencia e Innovación (Spain) and FEDER funds through the IBEPFOR (CGL2006- 00312/BOS) project. The NFI data were supplied by the Ministerio de Medio Ambiente y Medio Rural y Marino, Spain)

Ordenación forestal: ejercicios resueltos

Este libro recoge diez ejercicios sobre la aplicación práctica de los métodos para la ordenación sostenible de nuestros bosques, estructurados en dos partes: la primera dedicada a las masas coetáneas y regulares, y la segunda a las masas irregulares. Los ejercicios cuentan con una resolución detallada y amplias explicaciones, y se dirigen principalmente a alumnos de primer curso de ordenación de montes o gestión forestal

Apoyo de los sensores ópticos y de radar de apertura sintética a la información forestal

Aunque la teledetección, en su forma pionera de las fotografías aéreas, ha sido siempre utilizada como apoyo en los inventarios forestales, existe un cierto distanciamiento del uso intensivo de las imágenes de satélite, al menos en los países europeos de larga tradición en estos inventarios. En nuestra contribución, enunciamos vías de superación de estos problemas a partir de la presentación de (i) un análisis integrado detallado de datos de inventarios e imágenes de sensores ópticos en un parque natural mediterráneo (Sant Llorenç de Munt i L�Obac, Barcelona), y (ii) nuestro trabajo, en curso, sobre el análisis de las estimaciones realizadas a partir del radar de apertura sintética polarimétrico e interferométrico en la montaña del Corredor (Barcelona)