Carbon pools recover more quickly than plant biodiversity in tropical secondary forests.

Although increasing efforts are being made to restore tropical forests, little information is available regarding the time scales required for carbon and plant biodiversity to recover to the values associated with undisturbed forests. To address this knowledge gap, we carried out a meta-analysis comparing data from more than 600 secondary tropical forest sites with nearby undisturbed reference forests. Above-ground biomass approached equivalence to reference values within 80 years since last disturbance, whereas below-ground biomass took longer to recover. Soil carbon content showed little relationship with time since disturbance. Tree species richness recovered after about 50 years. By contrast, epiphyte richness did not reach equivalence to undisturbed forests. The proportion of undisturbed forest trees and epiphyte species found in secondary forests was low and changed little over time. Our results indicate that carbon pools and biodiversity show different recovery rates under passive, secondary succession and that colonization by undisturbed forest plant species is slow. Initiatives such as the Convention on Biological Diversity and REDD+ should therefore encourage active management to help to achieve their aims of restoring both carbon and biodiversity in tropical forests

Use of variety mixtures to reduce disease, increase resource-use efficiency resulting in enhanced profitability

This tool provides information on the use of mixtures to reduce disease in wheat-based rotations. Increasing diversity through sowing of mixtures can improve yield and reduce disease pressure. The tool is a power point presentation with research results and facts, providing information to farmers and agronomists working in integrated pest management in wheat-based systems in Europe. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7) under the grant agreement n°26586

Forest landscape restoration in the drylands of Latin America

Forest Landscape Restoration (FLR) involves the ecological restoration of degraded forest landscapes, with the aim of benefiting both biodiversity and human well-being. We first identify four fundamental principles of FLR, based on previous definitions. We then critically evaluate the application of these principles in practice, based on the experience gained during an international, collaborative research project conducted in six dry forest landscapes of Latin America. Research highlighted the potential for FLR; tree species of high socioeconomic value were identified in all study areas, and strong dependence of local communities on forest resources was widely encountered, particularly for fuelwood. We demonstrated that FLR can be achieved through both passive and active restoration approaches, and can be cost-effective if the increased provision of ecosystem services is taken into account. These results therefore highlight the potential for FLR, and the positive contribution that it could make to sustainable development. However, we also encountered a number of challenges to FLR implementation, including the difficulty of achieving strong engagement in FLR activities among local stakeholders, lack of capacity for community-led initiatives, and the lack of an appropriate institutional and regulatory environment to support restoration activities. Successful implementation of FLR will require new collaborative alliances among stakeholders, empowerment and capacity building of local communities to enable them to fully engage with restoration activities, and an enabling public policy context to enable local people to be active participants in the decision making process. © 2012 by the author(s). Published here under license by the Resilience Alliance

Grupos funcionales y variación en rasgos foliares y de tallo de 113 especies leñosas en un bosque seco tropical

In seasonally dry tropical forest (SDTF) plant trait variation has been associated with adaptation to light and water availability and a coordinated tolerance of plants to shortage of both resources has been proposed. We tested this hypothesis in a set of 113 species by analyzing the relationships amongst eleven leaf and stem traits that have been related to shade and drought tolerance. In addition, the usefulness of different types of functional classifications describing community plant trait variation was evaluated. Strong relationships were observed between leaf and stem traits, potentially conferring coordinated tolerance to shade and drought, and three axes of variation were identified by means of a principal component analysis. The first axis described leaf and stem economy, the second was related to leaf thickness and organization and the third was related to the trade-offs between leaf size, stem density and bark thickness. Stem density was correlated strongly with several plant traits, emphasizing its key role in explaining variation in life history strategies of SDTF species. Significant differences were found between functional groups categorized by phylogeny and leaf phenology, whereas for life forms differences were only observed for palms and bamboos. En los bosques secos tropicales (BST) la variación en rasgos vegetales se ha relacionado con adaptaciones a cambios en la disponibilidad de luz y agua y se ha propuesto una tolerancia coordinada a la escasez de ambos recursos. En este estudio probamos dicha hipótesis en un conjunto de 113 especies mediante el análisis de la relación entre once rasgos funcionales de hojas y tallos, que se han asociado con la tolerancia a la sombra y la sequía. Adicionalmente, evaluamos la utilidad de diferentes clasificaciones funcionales para describir la variación de los rasgos en la comunidad de plantas estudiada. Se observaron relaciones fuertes entre rasgos de las hojas y el tallo, otorgando potencialmente tolerancia a la sombra y la sequía, además se identificaron tres ejes de variación a través de un análisis de componentes principales. El primer eje se relacionó con la economía de hojas y tallo, el segundo con el grosor y la organización de las hojas y el tercero con compromisos entre el tamaño de hoja, la densidad del tallo y el grosor de la corteza. La densidad del tallo se relacionó fuertemente con varios rasgos, enfatizando su papel clave explicando la variación en las estrategias de historia de vida de las especies de BST. Se observaron diferencias significativas entre grupos funcionales categorizados por filogenia y fenología, mientras que entre formas de vida solo se observaron diferencias para las palmas y guaduas

Modelling the role of groundwater hydro-refugia in East African hominin evolution and dispersal.

Water is a fundamental resource, yet its spatiotemporal availability in East Africa is poorly understood. This is the area where most hominin first occurrences are located, and consequently the potential role of water in hominin evolution and dispersal remains unresolved. Here, we show that hundreds of springs currently distributed across East Africa could function as persistent groundwater hydro-refugia through orbital-scale climate cycles. Groundwater buffers climate variability according to spatially variable groundwater response times determined by geology and topography. Using an agent-based model, grounded on the present day landscape, we show that groundwater availability would have been critical to supporting isolated networks of hydro-refugia during dry periods when potable surface water was scarce. This may have facilitated unexpected variations in isolation and dispersal of hominin populations in the past. Our results therefore provide a new environmental framework in which to understand how patterns of taxonomic diversity in hominins may have developed

Habitat fragmentation intensifies trade-offs between biodiversity and ecosystem services in a heathland ecosystem in southern England

While habitat fragmentation represents a major threat to global biodiversity, its impacts on provision of ecosystem services are largely unknown. We analysed biodiversity value and provision of multiple ecosystem services in 110 fragments of lowland heathland ecosystems in southern England, in which vegetation dynamics have been monitored for over 30 years. Decreasing fragment size was found to be associated with a decrease in biodiversity and recreational values, but an increase in relative carbon storage, aesthetic value and timber value. The trade-off between either biodiversity or recreational values with the other ecosystem services therefore became more pronounced as heathland size decreased. This was attributed to a higher rate of woody succession in smaller heathland fragments over the past three decades, and contrasting values of different successional vegetation types for biodiversity and provision of ecosystem services. These results suggest that habitat fragmentation can reduce the potential for developing “win win” solutions that contribute to biodiversity conservation while also supporting socio-economic development. Approaches to multi-purpose management of fragmented landscapes should therefore consider the potential trade-offs in ecosystem services and biodiversity associated with fragmentation, in order to make an effective contribution to sustainable development

Identifying spring barley cultivars with differential response to tillage

Cultivars and some cultivar mixtures of spring barley were grown under inversion and non-inversion tillage conditions for three or four years and assessed for disease and yield in order to obtain genotypes that can be used to determine the mechanisms of cultivation adaptation. In general, the higher-yielding cultivars under inversion tillage conditions gave lower yields under non-inversion tillage, whereas low-yielding older cultivars showed relatively smaller reductions in yield under non-inversion tillage. A few cultivars showed preferential yield performance for either inversion or non-inversion tillage and this was irrespective of their overall yield performance. There was no pedigree or breeding programme link between these cultivars and no above-ground gross morphological trait observed was associated with tillage adaptation. Root hairs may contribute to inversion tillage adaptation as a root hair absence mutant was associated with non-inversion adaptation and it is likely that other root-associated traits are responsible also for tillage adaptation. There was no overall cultivar or tillage interaction with rhynchosporium symptoms but a differential tillage interaction may occur in individual years. We have identified clearly contrasting cultivars and tested their across-season robustness with respect to tillage treatment for further detailed mechanistic studies and identification of tillage adaptation traits

Using seed respiration as a tool for calculating optimal soaking times for 'on-farm' seed priming of barley (Hordeum vulgare)

A low-cost technique named ‘on-farm’ seed priming is increasingly being recognised as an effective approach to maximise crop establishment. It consists of anaerobically soaking seeds in water before sowing resulting in rapid and uniform germination, and enhanced seedling vigour. The extent of these benefits depends on the duration soaking time. Current determination of optimal soaking time by germination assays and mini-plot trials is resource-intensive, as it is species/genotype-specific. This study aimed to determine the potential of seed respiration rate (an indicator of metabolic activity) and seed morphological changes during barley priming as predictors of the priming benefits and, thus, facilitate determination of optimal soaking times. A series of germination tests revealed that germination rate is mostly attributable to rapid hydration of embryo tissues as the highest gains occurred before the resumption of respiration. Germination uniformity, however, was not significantly improved until seed were primed for at least 8 h, i.e. after a first respiration burst was initiated. The maximum seedling vigour was attained when the priming was stopped just before the beginning of the differentiation of embryonic axes (20 h) after which vigour began to decrease (‘over-priming’). The onset of embryonic axes elongation was preceded by a second burst of respiration, which can be used as a marker for priming optimisation. Thus, monitoring of seed respiration provides a rapid and inexpensive alternative to the current practice. The method could be carried out by agricultural institutions to provide recommended optimal soaking times for the common barley varieties within a specific region