Assessing conservation priorities of endemic freshwater fishes in the Tropical Andes region

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Beyond one bone: Interdisciplinarity to assess nativeness of the tench (Tinca tinca) in Spain

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Fish invading deserts: non‐native species in arid Moroccan rivers

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Growth and feed efficiency of Octopus vulgaris fed on dry pelleted

The purpose of this study was to evaluate the effect of two dry extruded diets on growth and nutritional composition of digestive gland (DG) and muscle of Octopus vulgaris. Both artificial diets (FMK and 3FMK) were composed of gelatin, maltodextrin, yolk, fish and krill meal. The 3FMK diet contained more fishmeal (3×) than the FMK diet. These diets were compared with a control frozen diet consisting of golden grey mullet (Liza aurata) and crab (Liocarcinus depurator). The 3FMK diet promoted higher intakes and feed efficiency than FMK diet, resulting in larger growths (296 respect to 158 g in 42 days; 0.81% vs. 0.78% body weight/day). There was significantly lower moisture, protein and ash content in digestive glands of animals fed pellets (P < 0.05). No significant differences were observed on nutritional composition of muscle among the three groups. Even though the results were still below those of the control group (increase of 1258 g), the good performance in terms of acceptance and growth showed that this extruded diet can be the starting point to develop a commercial feed for this species.     

Effect of two extruded diets with different fish and squid meal ratio on growth,digestibility and body composition of Octopus vulgaris (Cuvier, 1797)

The present work studies the growth and body composition of 18 Octopus vulgaris (6 per treatment) fed two extruded diets, namely FMS and 3FMS, based on different fish and squid meal ratios (1:1, and 3:1 respectively). The diets are compared with a control diet based on crab (Carcinus mediterraneus) and bogue (Boops boops). The growing tests were conducted on animals placed in individual 300 L rectangular fibreglass tanks in an open seawater system, containing PVC tubes as shelters, resulting in 100% survival rate. The control group exhibited the highest specific growth rates (SGR = 2.14%BW day^?1), while values of around 0.69%BW day^?1 were achieved by octopuses fed the extruded diets. Even though the three groups of animals showed similar digestive gland indexes, the two extruded diets promoted significant differences in the muscle composition and fatness of the digestive gland. Digestibility of dry matter was not affected by the type of extruded diet, obtaining ADC values of around 88%. The results suggest that squid and fish meal can be both used in dry pelleted extruded diets, with moderate acceptance by the octopus, even though the formulation must be optimized with the aim of improving acceptability and achieve growths in the range of natural diets.     

Alternative control of Chalara paradoxa,causal agent of black rot of pineapple by plant extract of Mormodica charantia

European Journal of Plant Pathology - Black rot of pineapple caused by the fungus Chalara paradoxa is considered an aggressive and difficult disease to control. The use of natural products has been...     

Why and where do adult trees die in a young secondary temperate forest? The role of neighbourhood

? The density and identity of tree neighbourhood is a key factor to explain tree mortality in forests, especially during the stem exclusion phase.

? To understand this process, we built a logistic model for mortality in a spatially explicit context, including tree and neighbourhood predictors. Additionally, we used this model to build mortality risk frequency distributions. Finally, we tested this model against a random mortality model to predict the spatial pattern of the forest.

? Annual mortality rate was high for pedunculate oak (Quercus robur, 6.99%), moderate for birch (Betula celtiberica, 2.19%) and Pyrenean oak (Q. pyrenaica, 1.58%) and low for beech (Fagus sylvatica, 0.26%). Mortality risk models for pedunculate oak and birch included stem diameter, tree height, canopy position and neighbourhood. Mortality was affected by the specific nature of the neighbourhood showing a clear competitive hierarchy: beech > pedunculate oak > birch. Models based on random mortality and logistic regression model were able to predict the spatial pattern of survivors although logistic regression predictions were more accurate.

? Our study highlights how simple models such as the random mortality one may obscure much more complex spatial interactions.

     

Effects of land use change on biodiversity and ecosystem services in tropical montane cloud forests of Mexico

Tropical montane cloud forests deliver important goods and services to society, such as timber, the supply and purification of fresh water, and carbon sequestration. In spite of their relevance, current deforestation rates are very high, at the expense of affecting the provision of ecosystem services. We explore the impact of land use change in terms of provision of ecosystem services by following two approaches, one very detailed (focused on hydrological services – water quality) and another one with a broader perspective (at a large scale and considering the ecosystem service value (ESV) of several ecosystems and their ecosystem services at the same time). In the highlands of the State of Veracruz, previously forested lands were converted into coffee plantations and cattle ranches. To evaluate the role of species composition and community structure on water quality, we studied nine small watersheds (<15 ha) covered by pristine cloud forest, coffee plantations and cultivated grassland (three each). Species richness of the three land use types was similar, although species composition was as different as 90%. Overall species diversity as well as that of woody species, and growth form diversities decreased in the transformed land uses. Water quality of streams flowing through these watersheds declined: nutrients (nitrate), conductivity, cations, chloride and suspended solids were lowest in the forest streams and highest in streams from coffee watersheds, whereas grasslands were intermediate. We also calculated ecosystem service values (using the transfer value method) and estimated economic market–non-market gains and losses owing to land transformation. Loss of natural ecosystems may imply a significant economic loss to society in terms of ecosystem services, although market gains may still lead land owners to land conversion because revenues are higher. Adequate Payment for Ecosystem Services may be a good option to prevent deforestation, but the compensation should be at least equal to the opportunity cost of the promoted land use. Our estimates are indicative of the urgent need to go beyond water quantity as the most relevant ecosystem service considered in PES schemes.     

Analysis of Andean blackberry (Rubus glaucus) production models obtained by means of artificial neural networks exploiting information collected by small-scale growers in Colombia and publicly available meteorological data

The Andean blackberry (Rubus glaucus) is an important source of income in hillside regions of Colombia. However, growers have little reliable information on the factors that affect the development and yield of the crop, and therefore there is a dearth of information on how to effectively manage the crop. Site specific information recorded by small-scale producers of the Andean blackberry on their production systems and soils coupled with publicly available meteorological data was used to develop models of such production systems. Multilayer perceptrons and Self-Organizing Maps were used as computational models in the identification and visualization of the most important variables for modeling the production of Andean blackberry. Artificial neural networks were trained with information from 20 sites in Colombia where the Andean blackberry is cultivated. Multilayer perceptrons predicted with a reasonable degree of accuracy the production response of the crop. The soil depth, the average temperature, external drainage, and the accumulated precipitation of the first month before harvest were critical determinants of productivity. A proxy variable of location was used to describe overall differences in management between farmers groups. The use of this proxy indicated that, even under essentially similar environmental conditions, large differences in production could be assigned to management effects. The information obtained can be used to determine sites that are suitable for Andean blackberry production, and to transfer of management practices from sites of high productivity to sites with similar environmental conditions which currently have lower levels of productivity.