Are Nested Networks More Robust to Disturbance? A Test Using Epiphyte-Tree, Comensalistic Networks

Recent research on ecological networks suggests that mutualistic networks are more nested than antagonistic ones and, as a result, they are more robust against chains of extinctions caused by disturbances. We evaluate whether mutualistic networks are more nested than comensalistic and antagonistic networks, and whether highly nested, host-epiphyte comensalistic networks fit the prediction of high robustness against disturbance. A review of 59 networks including mutualistic, antagonistic and comensalistic relationships showed that comensalistic networks are significantly more nested than antagonistic and mutualistic networks, which did not differ between themselves. Epiphyte-host networks from old-growth forests differed from those from disturbed forest in several topological parameters based on both qualitative and quantitative matrices. Network robustness increased with network size, but the slope of this relationship varied with nestedness and connectance. Our results indicate that interaction networks show complex responses to disturbances, which influence their topology and indirectly affect their robustness against species extinctions

Influence of number of flowers and number of previous and simultaneous foragers on bumblebees' local foraging decisions

The number of both flowers and co-foragers may affect bumblebees' local foraging decisions and the effort they devote to each flower during foraging. We studied bumblebees' local foraging decisions by using an experimental set-up in which bumblebees (Bombus terrestris) foraged for a single species (Salvia farinacea) in patches containing S. farinacea and Tagetes bonanza in varying densities (25, 50 and 75 % Salvia). We did not restrict the number of co-foragers, which allowed us also to assess the influence of simultaneous and previous foragers on foraging decisions. Bumblebees could adjust the effort per inflorescence and flower to the number of available inflorescences and flowers in the patch. They increased between-patch and between-plant movements as the number of previous foragers increased, and this effect was stronger in the patches with more Salvia, probably due to the synergic effects of number of flowers and number of previous foragers. Simultaneous foragers, on the contrary, favoured within-plant movements. The probability of leaving a patch was positively related to inflorescence exploitation time and to the number of previous foragers. The movements between patches followed Salvia abundance and were modified by the experience gained in the observation period. This experiment shed light on the influence of foragers' abundances on local foraging behaviour, and the interactions and synergies between flower abundance and foragers' abundances at a local scale, which are still much unknown. © 2014 Springer-Verlag Berlin Heidelberg and ISPAThis study was supported by the project 170532/V40, financed by the Norwegian Research Council. During the writing of this manuscript, AL was supported by a Juan de la Cierva contract, financed by the Spanish Ministry of Science and Innovation, and MP was supported by a JAE predoc contract, financed by the Spanish Council for Scientific ResearchPeer Reviewe

Seed dispersal by lizards on a continental-shelf island: Predicting interspecific variation in seed rain based on plant distribution and lizard movement patterns

16 páginas, 5 figuras, 1 tabla, 3 apéndicesAim We estimated the patterns of seed deposition provided by the eyed lizard, Timon lepidus, and evaluated whether these patterns can be generalized across plant species with different traits (fruit and seed size) and spatial distributions. Location Monteagudo Island, Atlantic Islands National Park (north-western Spain). Methods We radio-tracked seven lizards for 14days and estimated their home ranges using fixed kernels. We also geo-referenced all fruit-bearing individuals of four plant species dispersed by eyed lizards in the study area (Corema album, Osyris alba, Rubus ulmifolius and Tamus communis), measured the passage time of their seeds through the lizard gut, and estimated seed predation in four habitats (bare sand, grassland, shrub and gorse). Seed dispersal kernels were estimated using a combination of these data and were combined with seed predation probability maps to incorporate post-dispersal seed fate ('seed survival kernels'). Results Median seed gut-passage times were around 52-98h, with maximum values up to 250h. Lizards achieved maximum displacement in their home ranges within 24-48h. Seed predation was high (80-100% of seeds in 2months), particularly under Corema shrub and gorse. Seed dispersal kernels showed a common pattern, with two areas of preferential seed deposition, but the importance of these varied among plant species. Interspecific differences among dispersal kernels were strongly reduced by post-dispersal seed predation; hence, seed survival kernels of the different plant species showed high auto- and pairwise-correlations at small distances (<50m). As a result, survival to post-dispersal seed predation increased with dispersal distance for O. alba and T. communis, but not for C. album. Main conclusions Seed dispersal by lizards was determined primarily by the interaction between the dispersers' home ranges and the position of the fruit-bearing plants. As a result, seed rain shared a common template, but showed considerable variation among species, determined by their specific spatial context. Seed predation increased the spatial coherence of the seed rain of the different species, but also resulted in contrasting relationships between seed survival and dispersal distance, which may be of importance for the demographic and evolutionary processes of the plants. © 2012 Blackwell Publishing Ltd.This research was partially funded by the Spanish Ministry of Environment through its National Park Organism program (project grant 125/2005).A.R.L. and M.P. received funding support from the Spanish Scientific Research Council (JAEDoc and JAEpreDoc programs, respectively, co-funded by the European Social Fund), and J.R.P. was supported by a Marie Curie Intra European Fellowship (Grant Agreement Number PIEF-GA-2009-237097) within the 7th European Community Framework Programme.Peer reviewe

Seed dispersal in anthropogenic landscapes: incorporating the role of individual decisions by animal dispersers

Trabajo presentado en el 4º Congreso Ibérico de Ecología, celebrado en Coimbra, Portugal, del 16 al 19 de junio de 2015Peer Reviewe

Development of a real-time PCR assay for detection and quantification of Enteromyxum scophthalmi parasites in turbot intestinal samples

The myxozoan parasite Enteromyxum scophthalmi causes severe enteritis in cultured turbot Scophthalmus maximus, thus generating important economic losses. At present, there are no prevention or control measures for the disease, and many aspects of the life cycle and transmission of the parasite are not yet known. In this study, a highly sensitive, reproducible and rapid quantitative (real time) polymerase chain reaction (qPCR) assay was developed to detect E. scophthalmi DNA. The qPCR assay targets the 28S rRNA gene of the parasite, which has a high identity (94%) with the myxosporidian Enteromyxum leei rRNA gene. The qPCR assay was able to detect up to 13 DNA copies, corresponding to 0.55 fg, estimating that genomic DNA has around 1450 copies of 28S rRNA gene per parasite nucleus. The mean intra- and inter-assay coefficients of variation were below 5% and no detectable amplification was observed with DNA from non-infected turbot. The assay was validated with a histological identification of intestinal content samples from experimentally infected turbot and a good correlation between both methods was observed. The results demonstrate that the qPCR assay can be applied in the diagnosis of turbot enteromyxosis and to determine the relative abundance of E. scophthalmi in turbot intestinal contents in health monitoring studies.Peer reviewe

5 - Target sources of polyphenols in different food products and their processing by-products

This book chapter provides a description of the different natural sources of polyphenols, such as fruit and vegetables, cereals and legumes, coffee, tea, olive oil, cocoa, herbs and species. Industrial processing of these raw materials lead to the production of huge amount of by-products, which are a good source of antioxidants, mainly polyphenols. Recently, the recovery of these high-added-value compounds from food processing by-products is an important issue. Therefore, a particular attention in this chapter is focused on the new trend of food processing by-products and plant waste extracts as a source of polyphenols