Incorporating knowledge uncertainty into species distribution modelling

Monitoring progress towards global goals and biodiversity targets require reliable descriptions of species distributions over time and space. Current gaps in accessible information on species distributions urges the need for integrating all available data and knowledge sources, and intensifying cooperations to more effectively support global environmental governance. For many areas and species groups, experts can constitute a valuable source of information to fill the gaps by offering their knowledge on species-environment interactions. However, expert knowledge is always subject to uncertainty, and incorporating that into species distribution mapping poses a challenge. We propose the use of the dempster–shafer theory of evidence (DST) as a novel approach in this field to extract expert knowledge, to incorporate the associated uncertainty into the procedure, and to produce reliable species distribution maps. We applied DST to model the distribution of two species of eagle in Spain. We invited experts to fill in an online questionnaire and express their beliefs on the habitat of the species by assigning probability values for given environmental variables, along with their confidence in expressing the beliefs. We then calculated evidential functions, and combined them using Dempster’s rules of combination to map the species distribution based on the experts’ knowledge. We evaluated the performances of our proposed approach using the atlas of Spanish breeding birds as an independent test dataset, and further compared the results with the outcome of an ensemble of conventional SDMs. Purely based on expert knowledge, the DST approach yielded similar results as the data driven SDMs ensemble. Our proposed approach offers a strong and practical alternative for species distribution modelling when species occurrence data are not accessible, or reliable, or both. The particular strengths of the proposed approach are that it explicitly accounts for and aggregates knowledge uncertainty, and it capitalizes on the range of data sources usually considered by an expert

Montanera fattening average daily gain of Silvela iberian pigs according to growing system

Average daily gain during the montanera fattening period (grazing acorns and grass) of a flock of 84 pure Silvela Iberian pigs is analysed. A group was bred in an intensive system and the other one was bred in an traditional outdoor system. The results show better ADG in pigs from the traditional outdoor system but those confirm that is possible to obtain good performances with pigs from intensive system alter an adaptation to grazing period (0.87±0.02 kg versus 0.59±0.02 kg).Se analiza la ganancia media diaria a lo largo de los dos primeros meses de montanera de un grupo de 84 cerdos Ibéricos puros de la estirpe Silvela pertenecientes a dos grupos de recría diferentes: intensivo en parques y extensivo tradicional. Los resultados indican que se obtienen mejores resultados de ganancia media diaria con el sistema extensivo tradicional pero que es posible obtener buenos resultados con los cerdos procedentes del sistema intensivo, previa adaptación al pastoreo (0,87±0,02 kg versus 0,59±0,02 kg; p<0,001)

Archivos de Zootecnia. Informe Editorial 2010

The editorial process of Archivos de Zootecnia during 2010 is reported below. A total of 384 manuscripts were received from 33 countries, mainly from Brazil (66.9%). Consequently, the language most frequently used in the manuscripts was Portuguese, followed by Spanish and English. The mean time between submission and publication of a manuscript was 836.3 days. The rejection rate was 50.8%. In 2010, 49 articles, 21 short notes and 10 reviews (total 83) were published by authors coming from 15 countries.Se analiza el proceso editorial de Archivos de Zootecnia durante 2010. Se recibieron 384 manuscritos procedentes de 33 países, principalmente de Brasil (66,9%). Consecuentemente, el lenguaje más frecuentemente usado fue el portugués, seguido del español y el inglés. El tiempo medio entre recepción y publicación de un manuscrito fue elevado ( 836.3 dias). La tasa de rechazo fue del 50,8%. En 2010 fueron publicados 49 artículos, 21 notas breves y 10 revisiones (83 trabajos en total) cuyos autores pertenecían a 15 países diferentes

Archivos de Zootecnia: Informe Editorial 2008

The editorial process of Archivos de Zootecnia during 2008 is reported below. A total of 294 manuscripts were received from 24 countries mainly from Brazil (73%). Consequently, the language most frequently used in the manuscripts was Portuguese, followed by Spanish and English. The mean time between reception and publication of a manuscript was high (657 days). The rejection rate was 35.7%. In 2008, 42 articles, 30 short notes and 10 reviews (total 82) were published from 13 countries.Se revisa el proceso editorial de Archivos de Zootecnia durante 2008. Se recibieron 294 manuscritos procedentes de 24 países, principalmente de Brasil (73%). Consecuentemente, el primer idioma más utilizado fue el portugués seguido del español y el inglés. El tiempo medio entre recepción y publicación es elevado (657 días). La tasa de rechazo fue del 35,7%, publicándose 42 artículos, 30 notas breves y 10 revisiones bibliográficas, en total 82 contribuciones procedentes de 13 países

Archivos de Zootecnia. Informe Editorial 2009

The editorial process of Archivos de Zootecnia during 2009 is reported below. A total of 342 manuscripts were received from 24 countries, mainly from Brazil (75.8%). Consequently, the language most frequently used in the manuscripts was Portuguese, followed by Spanish and English. The mean time between submission and publication of a manuscript was 690.7 days. The rejection rate was 53.5%. In 2009, 44 articles, 72 short notes and 9 reviews (total 125) were published by authors from 29 countries. Se analiza el proceso editorial de Archivos de Zootecnia durante 2009. Se recibieron 342 manuscritos procedentes de 24 países, principalmente de Brasil (75,8%). Consecuentemente, el lenguaje más frecuentemente usado fue el portugués, seguido del español y el inglés. El tiempo medio entre recepción y publicación de un manuscrito fue elevado (690,7 dias). La tasa de rechazo fue del 53,5%. En 2009 fueron publicados 44 artículos, 72 notas breves y 9 revisiones (125 trabajos en total) cuyos autores pertenecían a 29 países diferentes

Generalized sampling: from shift-invariant to U-invariant spaces

The aim of this article is to derive a sampling theory in U-invariant subspaces of a separable Hilbert space ℋ where U denotes a unitary operator defined on ℋ. To this end, we use some special dual frames for L2(0, 1), and the fact that any U-invariant subspace with stable generator is the image of L2(0, 1) by means of a bounded invertible operator. The used mathematical technique mimics some previous sampling work for shift-invariant subspaces of L2(ℝ). Thus, sampling frame expansions in U-invariant spaces are obtained. In order to generalize convolution systems and deal with the time-jitter error in this new setting we consider a continuous group of unitary operators which includes the operator U

Experimental conditions for microhabitat selection in terrestrial snails

Habitat selection by terrestrial snails, used as laboratory animals, is an important factor because it can alter growth rates often used as a good biological indicator, moreover of its productive meaning. As support to the studies in this field, different models from election of microhabitat based on the individual selection or derived from other questions as the availability or the accessibility of the habitat or patron of movement of the organism are reviewed. Finally two experimental designs used in invertebrates under laboratorial conditions for preference studies are considered.La selección de hábitat por los caracoles terrestres que se utilizan como animales de experimentación, es importante porque condiciona el crecimiento y éste, además de su importancia productiva, es un buen indicador en muchos estudios. Como apoyo a los estudios en este campo, se revisan diferentes modelos de elección de microhábitat en función de la selección del propio individuo o bien derivados de cuestiones en buena parte ajenas a él como la disponibilidad o accesibilidad del hábitat o el patrón de movimiento del organismo. Finalmente se plantean dos diseños experimentales adecuados para el estudio de preferencia en invertebrados bajo condiciones de laboratorio

Malacological diversity in Andalusia. Renewable resource

The aim of this study is the evaluation of malacological diversity in Andalusian region. It has been observed high heterogeneity in relation to distribution patters of snails. Terrestrial edible snail populations are grouped in zones in relation to spatial distribution and specie. Zone I is located in Sierra Morena and shows a low density level of the most commonly edible species (O. lactea, H. aspersa, T. pisana and E. vermiculata). Zone II is extended throughout La Campiña and Vega del Guadalquivir. This zone is widely populated by snails with great economically importance: O. lactea and T. pisana and H. aspersa with a smaller density. Zone III is located in Sierras Béticas and it is characterised by the presence of many endemic populations (O. lactea murcica, O. punctata, T. pisana arietina, T. subdentata helicella, C. nemoralis, I. gualtierianus gualtierianus, I. gualtierianus alonensis, I. gualtierianus guiraoanus, etc.). It is necessary to develop strategic plans in order to conserve the malacological diversity in Andalusia.El objetivo del estudio es la evaluación de la diversidad malacológica andaluza como base del aprovechamiento de un recurso genético de interés económico. Se zonifican las poblaciones de caracoles comestibles existentes en Andalucía en relación al número de especies y su distribución geográfica. Se observa elevada heterogeneidad que da lugar a la conformación de tres zonas diferenciadas, en las que aparecen fundamentalmente los géneros Otala, Theba, Cantareus, Iberus, Eobania, Cepaea, Pseudotachea y Sphincterochila. La Zona I comprende Sierra Morena y se caracteriza por una baja presencia de caracoles, asociados mayoritariamente a la presencia humana y representados por las especies más comunes (O. lactea, H. aspersa, T. pisana y E. vermiculata). La Zona II comprende la Campiña y Vega del Guadalquivir, donde aparecen las especies de mayor valor comercial: O. lactea y T. pisana, con gran distribución; y H. aspersa con menor presencia. Finalmente la Zona III, que se integra por las Sierras Béticas donde aparecen, junto con las especies anteriormente citadas, gran diversidad de taxones con elevada singularidad, debido a la existencia de un número importante de endemismos y poblaciones relictas (O. lactea murcica, O. punctata, T. pisana arietina, T. subdentata helicella, C. nemoralis, I. gualtierianus gualtierianus, I. gualtierianus alonensis, I. gualtierianus guiraoanus, etc.). La existencia de esta biodiversidad justifica la necesidad de adoptar acciones estratégicas y planes específicos de conservación que preserven este recurso de forma eficaz

Acorn production at the dehesa: influential factors

This paper reviews the state-of-the-knowledge of acorn production in the South-Western Iberian dehesas. In the first part are briefly described the soil and climatic determining factors and phenology of most common trees of genus Quercus at the dehesa (Q. ilex, Q. suber and Q. faginea). In the second part, acorn production estimations are analyzed. Was established a mean acorn yield of 300 to 700 kg/ha; with individual productions of 8-14 kg/tree for Q. ilex, 5-10 kg/tree for Q. suber and 1-11 kg/tree for Q. faginea; with a highly variable production, both between and within years and individual trees. Finally we review the factors affecting acorn production, describing density of trees (estimated in 20-50 trees/ha), masting phenomenon (with cycles of 2-5,5 years and asynchrony between trees), individual cha-racteristics of trees (genetic potential, age, top surface, etc.), tree mass handling (with favourable effect of tilling, moderate pruning and sustainable grazing), meteorological conditions (mainly drought and meteorology during flowering) and sanitary status (Lymantria, Tortrix, Curculio, Cydia, Balaninus and Brenneria).Se revisa el conocimiento sobre la producción de bellota en las dehesas del SW de la Península Ibérica. Primero se analizan los condicionantes edafoclimáticos y la fenología de los principales árboles del género Quercus (Q. ilex, Q. suber y Q. faginea) presentes en las dehesas. A continuación se analiza la producción de bellota, que presentan valores medios de 300 a 700 kg/ha y producciones individuales de 8-14 kg/árbol para Q. ilex, 5-10 kg/árbol para Q. suber y 1-11 kg/árbol para Q. faginea; resultando producciones muy variables entre individuos, tanto intra como interanualmente. Finalmente, se revisan los factores que afectan a la producción de bellota; y entre éstos se describen la densidad de árboles (estimada en 20-50 pies adultos/ha), el fenómeno de la vecería (con ciclos de 2-5,5 años y asincronía entre árboles), las características individuales de los árboles (potencial genético, edad, superficie de copa, etc.), el manejo de la arboleda (con efecto favorable del laboreo, las podas ligeras y el pastoreo sostenible), las condiciones meteorológicas (principalmente sequía y meteorología durante la floración) y el estado sanitario (Lymantria, Tortrix, Curculio, Cydia, Balaninus y Brenneria)