Effects of woodland islets introduced in a Mediterranean agricultural landscape on local bird communities

This study assesses whether the afforestation approach consisting in the introduction of woodland islets in “agricultural seas” can reconcile the restoration of woody vegetation and the persistence of open-habitat bird populations, providing further opportunities for other forest species to enrich bird diversity at the landscape level. We compared the species richness and abundance of bird communities in a field with 16 introduced woodland islets and in a nearby abandoned field located in central Spain during spring and winter time. The woodland islets presented higher accumulated species richness as well as a higher probability of finding new species if sampling effort were increased only in winter time. These trends were the opposite during spring time. Mean species richness and mean bird abundance were lower at the woodland islets than at the abandoned field in both seasons. We found a higher abundance of open-habitat specialist species in the abandoned field. Woodland islets favoured the wintering of chiffchaff Phylloscopus collybita. We did not find any effects on the only forest specialist species (blue tit Parus caeruleus) in spring. Bird richness and abundance were higher in edge islets than in inner islets. The introduction of larger and mixed plantations connected by hedgerows and a management that favoured the development of big trees, a lower tree density and a diverse shrub layer could promote bird diversity, allowing forest specialists and open-habitat species to coexist at the landscape scale

Plant diversity, biogeography and environment in Iberia: Patterns and possible causal factors

Las figuras que contiene el documento se localizan al final del mismoWe associated patterns of plant diversity with pos- sible causal factors by considering 93 local regions in the Iberian Peninsula and Balearic Islands with respect to biogeo- graphy, environmental favourability, and environmental hetero- geneity, and their relationship with measured species diversity at four different scales: mean local species richness standard- ized at a grain of 100 m 2 , total species richness in a community type within a region (regional community richness), mean compositional similarity, and mosaic diversity. Local regions in biogeographic transition zones to the North African and Atlantic floras had higher regional commu- nity richness and greater mosaic diversity than did non-transi- tional regions, whereas no differences existed in mean local species richness or mean compositional similarity. Mean local species richness was positively related to environmental fa- vourability as measured by actual evapotranspiration, but negatively related to total precipitation and temporal heteroge- neity in precipitation. Mean local species richness was great- est in annual grassland and dwarf shrubland communities, and on calcareous bedrock types. Regional community richness was similarly related to actual evapotranspiration and total precipitation, but in addition was positively related to spatial heterogeneity in topography and soil water holding capacity. Mean compositional similarity decreased with increasing spa- tial heterogeneity and temperature seasonality. Mosaic diver- sity, a measure of complexity, increased with increasing local and regional richness. We hypothesize that these relationships can be explained by four ecological and evolutionary classes of causal factors: nu mbers of individuals, intermediate environments, limits to adaptation, and niche variation. These factors operate at various scales and manifest themselves in various ways. For example, at the site level, apparently processes that increase the number of individuals increase mean local species richness, but at the level of the entire region no such effects were foundWe are deeply indebted to Íñigo Vázquez- Dodero for his assistance in the early stages of this study. Jose M. Rey Arnaiz provided climate data. Emilio Chuvieco pro- vided the remote sensing data. Julio Álvarez, Javier Amigo, Carmen Bartolomé, and Marcelino de la Cruz provided useful information for finding data sets. Manuel Segura and Javier Temiño assisted with the classification of bedrock and soil types. Diana Piorno, Carmen Pineda, and Francisco Bermejo assisted with data entry. Meelis Pärtel, Mike Willig, Brad Hawkins, Sandra Lavorel, Jane Franklin, and R.M. Cowling provided comments about a previous version of this manu- script. This study was funded by the “Determinantes de la diversidad biológica en ecosistemas mediterráneos. Papel de los procesos locales y regionales” project (CICYT AMB96- 1161), and additionally supported by the ”Factores limitantes de la revegetación con especies leñosas autóctonas de áreas degradadas en ambientes mediterráneos. Rendimiento de distintas actuaciones de manejo” project (CICYT REN 2000 745). Travel by J.M.R.B. and S.M.S. was funded by the Universidad de Alcalá. The views expressed in this paper do not necessarily reflect those of the National Science Founda- tion or the United States Governmen

Clipping herbaceous vegetation improves early performance of planted seedlings of the Mediterranean shrub Quercus coccifera

We tested how the conditions resulting from alternative management strategies addressed to mitigate abiotic and biotic limitations to plant establishment affect the performance of planted Quercus coccifera seedlings. This species is a xerophytic and heliophillous Mediterranean shrub, of interest for the restoration of abandoned farmland. We hypothesised that release from herb competition by clipping would allow Q. coccifera seedlings to cope more efficiently with water shortage by adjusting their mass allocation pattern. We established three environments of herb competition: absence of competition (AC), reduced competition by clipping (RC), and total competition (TC); and applied two irrigation treatments: low and high irrigation. We measured soil moisture at different depths, above- and below-ground herb biomass, and evaluated seedling responses, such as mortality, growth, biomass allocation, and morphological and physiological features. The TC treatment reduced water availability more than the RC treatment, in agreement with the highest water stress of seedlings under TC conditions. Irrigation increased above- and below-ground herb biomass, whereas clipping reduced herb production. Release of herb competition by clipping increased seedling survivorship by one order of magnitude and resulted in a growth rate comparable to the absence of competition. This growth was mostly related to carbon gain allocated to roots. The competition intensity imposed by treatments was related to a parallel reduction in total plant leaf area, biomass allocated to leaves and shoot:root ratio, and an increase in biomass allocated to roots and leaf mass area. The negative effects of herbs on Q. coccifera seedlings seem the result of competition for both water and light, in contrast with previous research with more mesic Quercus species, for which competition is primarily for water. Clipping of herbs is a feasible technique that greatly improved seedling performance, and thus a valuable alternative to herbicide application, common in native plantations aimed at restoring Mediterranean farmland

Restauración de campos agrícolas sin competir por el uso de la tierra para aumentar su biodiversidad y servicios ecosistémicos

Los autores que publican en esta revista están de acuerdo con los siguientes términos: Los autores conservan los derechos de autor y garantizan a la revista el derecho de ser la primera publicación del trabajo licenciado según una licencia de atribución Creative Commons que permite a otros compartir el trabajo con el reconocimiento de la autoría y de la publicación en la que se publicó por primera vez. Los autores pueden establecer por separado acuerdos adicionales para la distribución no exclusiva de la versión de la obra publicada en la revista (por ejemplo, situarlo en un repositorio institucional o publicarlo en un libro), con el reconocimiento de haber sido publicado primero en esta revista. Se permite y se anima a los autores a difundir sus trabajos electrónicamente (por ejemplo, en repositorios institucionales o en su propio sitio web) antes y durante el proceso de envío, ya que puede dar lugar a intercambios productivos, así como a una citación más temprana y mayor de los trabajos publicados.La restauración ecológica es capaz de aumentar la biodiversidad y los servicios ecosistémicos en los agro-sistemas con el objetivo de contrarrestar los impactos ambientales negativos de la expansión y de la intensificación agrícola. Una forma de conseguir este aumento es mediante acciones de restauración o creación estratégica de elementos clave que benefician a especies silvestres y a servicios ecosistémicos particulares sin competir por el uso de la tierra, a la vez que benefician a los cultivos. Algunas de estas acciones son la introducción de setos, charcas y cajas-nido para depredadores de roedores. La implementación de estas acciones de forma generalizada en el mundo contribuiría de forma importante a conciliar la producción agrícola y la conservación de la biodiversidad.Ecological restoration is capable of enhancing biodiversity and ecosystem services in agro-systems to counteract the negative impacts related to agricultural spread and intensification. An approach to get such enhancement is by means of restoring or creating target elements to benefit wildlife and particular services without competition for land use, including agricultural production. Introduction of hedge rows, ponds, and nest boxes for rodent predators are examples of such actions. Wide implementation of these actions is critical to conciliate agricultural production and biodiversity conservation

Restauración de campos agrícolas sin competir por el uso de la tierra para aumentar su biodiversidad y servicios ecosistémicos

Los autores que publican en esta revista están de acuerdo con los siguientes términos: Los autores conservan los derechos de autor y garantizan a la revista el derecho de ser la primera publicación del trabajo licenciado según una licencia de atribución Creative Commons que permite a otros compartir el trabajo con el reconocimiento de la autoría y de la publicación en la que se publicó por primera vez. Los autores pueden establecer por separado acuerdos adicionales para la distribución no exclusiva de la versión de la obra publicada en la revista (por ejemplo, situarlo en un repositorio institucional o publicarlo en un libro), con el reconocimiento de haber sido publicado primero en esta revista. Se permite y se anima a los autores a difundir sus trabajos electrónicamente (por ejemplo, en repositorios institucionales o en su propio sitio web) antes y durante el proceso de envío, ya que puede dar lugar a intercambios productivos, así como a una citación más temprana y mayor de los trabajos publicados.La restauración ecológica es capaz de aumentar la biodiversidad y los servicios ecosistémicos en los agro-sistemas con el objetivo de contrarrestar los impactos ambientales negativos de la expansión y de la intensificación agrícola. Una forma de conseguir este aumento es mediante acciones de restauración o creación estratégica de elementos clave que benefician a especies silvestres y a servicios ecosistémicos particulares sin competir por el uso de la tierra, a la vez que benefician a los cultivos. Algunas de estas acciones son la introducción de setos, charcas y cajas-nido para depredadores de roedores. La implementación de estas acciones de forma generalizada en el mundo contribuiría de forma importante a conciliar la producción agrícola y la conservación de la biodiversidad.Ecological restoration is capable of enhancing biodiversity and ecosystem services in agro-systems to counteract the negative impacts related to agricultural spread and intensification. An approach to get such enhancement is by means of restoring or creating target elements to benefit wildlife and particular services without competition for land use, including agricultural production. Introduction of hedge rows, ponds, and nest boxes for rodent predators are examples of such actions. Wide implementation of these actions is critical to conciliate agricultural production and biodiversity conservation

Holistic management approach as a tool for dehesa/montado restoration

PosterDehesa/montado can be defined as a multi-purpose agroforestry system with scattered oak trees. This ecosystem covers an estimated 3.1 million ha and is the most extended silvopastoral system and the largest High Nature Value Farming System in Europe. However, the sustainability of dehesas/montados has been questioned in recent years because of trends towards more intensive and simplified management, which in turn have led to changes in vegetation and soil properties and increased soil erosion rates. Holistic Management approach, based on time-controlled grazing systems, not only increases productivity but also implies ecosystem improvements: soil properties (soil structure, amount of organic matter, water efficiency, and availability soil nutrients) and pasture species cover and composition. McCoster (2000) has described a synergistic effect between a cell grazing (similar to HM) and trees regeneration in Australia. The main goal of this study is to evaluate the effect of the Holistic Management Grazing Approach on the soil properties, trees recovery, pasture cover, biodiversity and productivity opposite to nowadays continuous grazing management and different pasture innovations in Spanish and Portuguese dehesa/montado farms

¿Coinciden los espacios naturales protegidos con las áreas relevantes de diversidad de herpetofauna en España peninsular y Baleares?

Debido a los elevados costes de la conservación, es importante priorizar áreas de actuación que permitan optimizar la inversión realizada. En este trabajo se identifican las áreas relevantes de biodiversidad de anfibios y reptiles en España peninsular e Islas Baleares. Para identificar estas áreas se han usado cuatro criterios, que proporcionaron distintos grados de eficacia o inclusión de especies, particularmente las amenazadas, en las áreas relevantes definidas por ellos. Se examina también la coincidencia geográfica entre dichas áreas relevantes y la red de Espacios Naturales Protegidos (ENPs), detectándose una serie de huecos que se propone completar con nuevos ENPs. Más allá de la explicación de la distribución de las áreas relevantes de biodiversidad, donde intervienen procesos ecológicos y evolutivos, creemos que estudios como éste pueden ayudar a la identificación de zonas del territorio especialmente valiosas para la conservación de la biodiversidad.Estas investigaciones se han beneficiado parcialmente del proyecto "Factores limitantes de la revegetación con especies leñosas autóctonas de áreas degradadas en ambientes mediterráneos. Rendimiento de distintas actuaciones de manejo" (REN2000 745) de la CICYT

Shifting demographic conflicts across recruitment cohorts in a dynamic post-disturbance landscape

Seed dispersal effectiveness, which measures the number of adult plant individuals produced by seed dispersal, is the product of the number of seeds dispersed and the probability a seed produces an adult. Directed dispersal to certain habitat types may enhance some stages of recruitment but disfavor others, generating demographic conflicts in plant ontogeny. We asked whether temporal changes in habitat features may affect the distribution of seedlings recruited from dispersed acorns, and whether this could induce shifts in the life-stage conflicts experienced by successive cohorts of naturally recruited plants. As early successional habitats are characterized by rapid change, we used a burnt pine stand in southern Spain to monitor the recruitment and performance of a major tree species (Quercus ilex) across 7 yr in four types of post-fire habitats. These differed in structure and included patches of unburnt forest and three management alternatives of burnt trees: logging, partial cutting, and nonintervention. Young oaks that resprouted after the fire were mainly located near acorn sources, while new seedlings initially emerged mostly in habitats with standing snags due to habitat selection by European jays, Garrulus glandarius, for dispersal. The dead pines gradually collapsed and attracted less dispersal, so subsequent seedling cohorts mainly recruited within patches of unburnt pines. These live pines enhanced the survival of the oaks located beneath their canopy but greatly reduced their growth as compared to the other post-fire habitats, thus representing a demographic conflict that was absent elsewhere. As a consequence of the directional shift in the habitat where seedlings recruited, successive seedling cohorts experienced a gradual improvement in their likelihood of survival but a reduction in growth. The progressive intensification of this life-stage conflict hinged on the reduction of vertical structures in the habitat with standing burnt pines. Recruitment success thus involved temporal variation in the habitat where recruitment occurred, likely resulting from changes in the direction of seed dispersal, and spatial variation in habitat suitability for seedling establishment and growth. Temporal changes in habitat structure can indirectly change the environment in which recruitment occurs, and consequently seed dispersal effectiveness, by shifting the direction of seed dispersal.Ministerio de Ciencia e InnovaciónComunidad de MadridMinisterio de Ciencia y Educació

Models for biomass estimation in native forest tree plantations and secondary forests in the Costa Rican Caribbean Region

The use of forest ecosystems as carbon sinks is now more accepted. However, credible information about its growth in terms of\ud biomass and its capacity to capture and store CO2 is still insufficient in order to suggest ways by which forest owners should be\ud compensated. The objective for this study was to construct models that allow us to determine tree biomass for native tree plantations\ud of Hieronyma alchorneoides Allemào, Vochysia guatemalensis Donn and a group of 35 species of secondary forests in the\ud Costa Rican Caribbean region. In each plantation the tree with the mean diameter at breast height (d) was harvested; in secondary\ud forests the harvested tree corresponded to the mean d tree with the highest Importance Value Index (IVI) for each diametric class.\ud Destructive sampling was used, separating each tree component and collecting a field sample in order to determine dry matter\ud content (MS). All selected models had R2aj values above 82.6%. Tree species from secondary forests showed the lowest R2aj\ud values. Stem, roots and total biomass had R2aj values above 91.3%, while leaves and branches had values between 82.6 and 94.1%.\ud Biomass expansion factor (BEF) in secondary forest was 1.44 and in forest tree plantations it was 1.56. The radical biomass (Bra)\ud relationship to total aboveground biomass (Bat) and stem biomass (Bf) in secondary forests was 0.25 and 0.37, respectively, 0.26\ud and 0.39 for V. guatemalensis and 0.3 and 0.52 for H. alchorneoides.El uso de los ecosistemas forestales como sumideros y reservorios de carbono es cada día más aceptado. Aún así, la información\ud fidedigna sobre su crecimiento en biomasa y la capacidad de captura y de almacenamiento de CO2 es insuficiente para proponer\ud formas de compensación a los propietarios de bosques. El objetivo de este trabajo fue construir modelos para estimar la biomasa\ud del árbol en plantaciones de Hieronyma alchorneoides, Vochysia guatemalensis y para un grupo de 35 especies en bosque secundario,\ud en la zona Caribe de Costa Rica. En cada plantación se extrajo un árbol de diámetro promedio a la altura del pecho (d) y en\ud bosque secundario un árbol de d promedio de la especie de mayor índice de valor de importancia por clase diamétrica. Se utilizó\ud un muestreo destructivo, separando cada componente del árbol y tomando una muestra de campo para determinar la materia seca.\ud Todos los modelos seleccionados tuvieron un R2aj superior al 82,6%. Las especies arbóreas de bosque secundario mostraron R2aj\ud inferiores. El fuste, raíz y biomasa total del árbol mostraron R2aj > 91,3%, y las hojas y ramas, entre 82,6 y 94,1%. El factor de\ud expansión de biomasa en bosque secundario fue de 1,44 y en plantaciones de 1,56. Se estimó que la relación de biomasa radical\ud respecto a biomasa aérea total y biomasa del fuste fue 0,25 y 0,37, respectivamente, en bosques secundarios; 0,26 y 0,39 en V.\ud guatemalensis, y 0,3 y 0,52 en H. alchorneoides.Este trabajo ha sido financiado por la Universidad\ud Nacional Autónoma de Costa Rica, el Ministerio de Ciencia\ud y Tecnología de Costa Rica y gracias al apoyo de la empresa\ud privada. El primer autor se benefició de una beca del\ud Programa Miguel de Cervantes para realizar su tesis doctoral\ud en la Universidad de Alcalá de Henares, España