Estudio de la estructura y composición de carbonales (Acacia pennatula) en dos estadios de desarrollo. Diseño de protocolo para el seguimiento de la dinámica de la vegetación en el CIEA "El Limón", Estelí (Nicaragua)

Los carbonales son un tipo de bosque secundario originados por el abandono de un sistema de producción silvopastoril. Estos parches de bosque ocupan una superficie importante de la zona de amortiguamiento de la Reserva Natural del Tisey-La Estanzuela, área del bioma más amenazado del mundo, el Bosque Seco Tropical. La principal especie que compone esta comunidad vegetal es la Acacia pennatula, conocida comúnmente como carbón. Actualmente no hay muchos estudios sobre los carbonales, por lo que el presente proyecto pretende caracterizar la estructura y composición de la comunidad y describir algunos índices ecológicos básicos, en dos estadios diferentes. El análisis de los datos proporciona información de las principales diferencias en cuanto a estructura y composición que tienen lugar en los carbonales. La disminución natural de la densidad de individuos de A. pennatula con los años, parece tener un efecto positivo sobre la diversidad, composición y estructura de la comunidad. En base a estos datos, se ha diseñado un protocolo para realizar un estudio experimental de estas comunidades en el CIEA "El Limón". En el protocolo, mediante diferentes tratamientos de tala en estadios tempranos, se obtendrán áreas de estudio que presenten un gradiente en la variable densidad de individuos de A. pennatula. El objetivo principal es describir y comparar la estructura, composición y dinámica del carbonal a lo largo del tiempo, y determinar que efecto tiene sobre la comunidad modificar esta variable. Los resultados obtenidos en el protocolo pueden utilizarse como base para desarrollar un plan de manejo para los carbonales que facilite la restauración del Bosque Tropical Seco y el aprovechamiento forestal.Els carbonals són un tipus de bosc secundari originats per l'abandonament d'un sistema de producció silvopastoril. Aquestes fraccions de bosc ocupen una superfície important de la zona d'amortiguament de la Reserva Natural del Tisey-La Estanzuela, àrea del bioma més amenaçat del món, el Bosc Tropical Sec. La principal espècie que conforma aquesta comunitat vegetal es l' Acacia pennatula, coneguda popularment com a carbó. Actualment no hi ha molts d'estudis sobre els carbonals, fet pel qual el present projecte pretén caracteritzar l'estructura i composició de la comunitat i descriure alguns índexs ecològics bàsics, en dos estadis diferents. L'anàlisi de les dades proporciona informació precisa de les principals diferencies i processos que tenen lloc als carbonals. La disminució natural de la densitat d'individus d' A. pennatula amb els anys, sembla tenir un efecte positiu sobre la diversitat, composició i estructura de la comunitat. D'acord amb aquestes dades, s'ha dissenyat un protocol per a realitzar un estudi experimental d'aquestes comunitats al CIEA "El Limón". Al protocol, mitjançant diferents tractaments de tala en estadis joves, s'obtindran àrees d'estudi que presentin un gradient a la variable densitat d'individus d' A. pennatula. L'objectiu principal es descriure i comparar la estructura, composició i dinàmica del carbonal al llarg del temps, i determinar si existeix un efecte positiu al modificar aquesta variable. Els resultats obtinguts al protocol es poden utilitzar com a base per a desenvolupar un pla d'actuació para els carbonals que faciliti la restauració del Bosc Tropical Sec i l'aprofitament forestal.The "carbonales" are a type of secondary forests developed due to the vacated of a silvopastoral system. Those forest fractions occupy an important surface of the Natural Reserve Tisey-La Estanzuela buffer's zone, where we find the world's most threatened biome, the Tropical Dry Forest. The main species of this plant community is Acacia pennatula, commonly known as "carbón". Nowadays there are not many studies about "carbonales", so this project has the aims to characterize, in two different stages, the structure and the composition of the community and describe some basic ecological indices. The data analysis gives accurate information of the main differences and processes taking place in the "carbonales". The natural decrease of the A. pennatula's density over the years seems to have a positive effect on the diversity, the composition and the structure of the community. Based on this, a protocol for an experimental study on those communities in the CIEA "El Limón" has been designed. In the protocol, we will obtain study areas with different density of A. pennatula by different logging treatments in early stages. The main objectives is to describe and compare the structure, the composition and the dynamics of the "carbonal" over time, and determine if there is a positive effect when density is modified. The results obtained from the protocol can be used as the basis to develop a management plan for "carbonales" in order to facilitate the Tropical Dry Forest's restoration and forestry

Presence of Vibrio mediterranei associated to major mortality in stabled individuals of Pinna nobilis L.

A major epizootic event attributed to Haplosporidium pinnae leading to 100% mortality of Pinna nobilis L. populations along Mediterranean coastlines started in the fall of 2016. As a result, a project to rescue 221 adult individuals of the endangered pen shell, Pinna nobilis was conducted in November 2017 in the two areas of the Spanish coast where the species was still abundant and apparently free from infection by H. pinnae: Port Lligat in the Costa Brava, and the Alfacs Bay in the Ebro Delta. For biosecurity reasons, the 106 individuals from the Ebro Delta were stabled at the IRTA facilities located next to Alfacs Bay, whereas the 115 individuals from Port Lligat were stabled in different institutions throughout the Spanish territory. Initial biopsies showed that individuals from the Ebro Delta were free of the parasite, whereas most individuals from Port Lligat were already parasitized and died in the following months. Individuals at IRTA were hold in five tanks and fed ca. 4% of their dry weight with a mix of three species of phytoplankton and fine riverine sediments (13% OM). Seawater was filtered through 10, 5 and 1 μm to ensure the absence of the parasite and disinfected with UV light. No individuals died during the 4 initial months of captivity, but two died in April–May at temperatures from 17 to 19 °C. A peak of mortalities occurred during the summer months and early fall (53%) with maximums coinciding with temperatures above 25 °C. Individuals were again analyzed by PCR and histology for the presence of H. pinnae, Mycobacteria sp., and other locally important pathogens of commercial bivalves (Vibrio splendidus, V. aestuarianus and Herpesvirus OsHV-1 microVar), and therefore considered as potential pathogens of pen shells. However, with the exception of 3 individuals that were positive for Mycobacteria sp., results were all negative for the studied pathogens. Microbiological culture and isolation of bacteria from three moribund individuals, sacrificed for study purposes, showed V. mediterranei as the dominant species, and further PCR analyses confirmed the presence of the bacterium in ten deceased individuals. Overall, our results suggest the V. mediterranei is an opportunistic pathogen of stabled individuals possibly subjected to stress from captivity, and that antibiotic treatment (Florfenicol) combined with vitamins and mineral supplementation and reduction of water temperature (15 to 18 °C), can be used to mitigate (not to eradicate) the disease. Further research is needed to determine diets and stabling conditions that minimize captivity stress and prevent the emergence of the disease.info:eu-repo/semantics/acceptedVersio

Stable isotope analyses reveal major nutritional deficiencies in captive vs. field juvenile individuals of Pinna nobilis

The pen shell, Pinna nobilis L. is critically endangered by the spread of a haplosporidan parasite. Stable isotopes have been shown an association with dietary assimilation, trophic level, and body condition, and can provide valuable information for ex situ conservation and breeding. In this context, the aim of this study was to investigate the nutritional status of individuals using δ13C and δ15N patterns across pen shell body tissues as tracers of elemental incorporation from treatment diets based on commercial gels and living phytoplankton and/or sediment. Further comparisons were also conducted with field animals and diets to better understand nutritional needs. Captive individuals, were enriched in δ13C and δ15N (~18.9 and 1.3‰, respectively), suggesting severe nutritional stress and utilization of own N and C pools, especially muscle. The mixing model for field individuals evidenced a large contribution from the zooplankton fraction (34.9%), which was further confirmed by experimental feeding with Artemia nauplii.info:eu-repo/semantics/acceptedVersio

Prey size and species preferences in the invasive blue crab, Callinectes sapidus: Potential effects in marine and freshwater ecosystems

The blue crab, Callinectes sapidus is an invasive species in the Mediterranean region. In Ebro Delta bays, it poses an important risk for the cultivation of Mediterranean mussel (Mytillus galloprovincialis) and Pacific oyster (Crassostrea gigas). Besides, the species thrives in the Ebro River hosting abundant populations of apple snail (Pomacea maculata) and Asian clam (Corbicula fluminea). Food-preference experiments were conducted to assess the effect of predator and prey sizes and prey type (M. galloprovincialis vs. C. gigas and P. maculata vs. C. fluminea) in predation patterns and its possible causes. Our results show that except for the Pacific oyster, which attains protection at sizes of 50–70 mm and was little consumed (0–16%), the other preys are readily predated, at variable rates (mussels: 38–96%; apple snail: 58–93%, and Asian clam: 67–100%), depending on predator and prey sizes. Juveniles and young blue crab adults showed greater consumption of small and medium mussels and a similar trend occurred with Asian clam. In contrast, large and medium apple snails were more heavily predated by adult blue crabs. Species comparisons also showed higher predation of mussels than oysters (71 vs. 8%), and of apple snail than Asian clam (99 vs. 72%). Once the shell barrier was removed, preference for mussels was still preserved, suggesting a nutritional preference. Our results point the need of fishing blue crab in marine areas to prevent losses in mussel production and highlight the potential control exerted over undesired invasive mollusk species.info:eu-repo/semantics/acceptedVersio

Estudio de la estructura y composición de carbonales (Acacia pennatula) en dos estadios de desarrollo. Diseño de protocolo para el seguimiento de la dinámica de la vegetación en el CIEA "El Limón", Estelí (Nicaragua)

Los carbonales son un tipo de bosque secundario originados por el abandono de un sistema de producción silvopastoril. Estos parches de bosque ocupan una superficie importante de la zona de amortiguamiento de la Reserva Natural del Tisey-La Estanzuela, área del bioma más amenazado del mundo, el Bosque Seco Tropical. La principal especie que compone esta comunidad vegetal es la Acacia pennatula, conocida comúnmente como carbón. Actualmente no hay muchos estudios sobre los carbonales, por lo que el presente proyecto pretende caracterizar la estructura y composición de la comunidad y describir algunos índices ecológicos básicos, en dos estadios diferentes. El análisis de los datos proporciona información de las principales diferencias en cuanto a estructura y composición que tienen lugar en los carbonales. La disminución natural de la densidad de individuos de A. pennatula con los años, parece tener un efecto positivo sobre la diversidad, composición y estructura de la comunidad. En base a estos datos, se ha diseñado un protocolo para realizar un estudio experimental de estas comunidades en el CIEA “El Limón”. En el protocolo, mediante diferentes tratamientos de tala en estadios tempranos, se obtendrán áreas de estudio que presenten un gradiente en la variable densidad de individuos de A. pennatula. El objetivo principal es describir y comparar la estructura, composición y dinámica del carbonal a lo largo del tiempo, y determinar que efecto tiene sobre la comunidad modificar esta variable. Los resultados obtenidos en el protocolo pueden utilizarse como base para desarrollar un plan de manejo para los carbonales que facilite la restauración del Bosque Tropical Seco y el aprovechamiento forestal.Els carbonals són un tipus de bosc secundari originats per l’abandonament d’un sistema de producció silvopastoril. Aquestes fraccions de bosc ocupen una superfície important de la zona d’amortiguament de la Reserva Natural del Tisey-La Estanzuela, àrea del bioma més amenaçat del món, el Bosc Tropical Sec. La principal espècie que conforma aquesta comunitat vegetal es l’ Acacia pennatula, coneguda popularment com a carbó. Actualment no hi ha molts d’estudis sobre els carbonals, fet pel qual el present projecte pretén caracteritzar l’estructura i composició de la comunitat i descriure alguns índexs ecològics bàsics, en dos estadis diferents. L’anàlisi de les dades proporciona informació precisa de les principals diferencies i processos que tenen lloc als carbonals. La disminució natural de la densitat d’individus d’ A. pennatula amb els anys, sembla tenir un efecte positiu sobre la diversitat, composició i estructura de la comunitat. D’acord amb aquestes dades, s’ha dissenyat un protocol per a realitzar un estudi experimental d’aquestes comunitats al CIEA “El Limón”. Al protocol, mitjançant diferents tractaments de tala en estadis joves, s’obtindran àrees d’estudi que presentin un gradient a la variable densitat d’individus d’ A. pennatula. L’objectiu principal es descriure i comparar la estructura, composició i dinàmica del carbonal al llarg del temps, i determinar si existeix un efecte positiu al modificar aquesta variable. Els resultats obtinguts al protocol es poden utilitzar com a base per a desenvolupar un pla d’actuació para els carbonals que faciliti la restauració del Bosc Tropical Sec i l’aprofitament forestal.The “carbonales” are a type of secondary forests developed due to the vacated of a silvopastoral system. Those forest fractions occupy an important surface of the Natural Reserve Tisey-La Estanzuela buffer’s zone, where we find the world’s most threatened biome, the Tropical Dry Forest. The main species of this plant community is Acacia pennatula, commonly known as “carbón”. Nowadays there are not many studies about “carbonales”, so this project has the aims to characterize, in two different stages, the structure and the composition of the community and describe some basic ecological indices. The data analysis gives accurate information of the main differences and processes taking place in the “carbonales”. The natural decrease of the A. pennatula’s density over the years seems to have a positive effect on the diversity, the composition and the structure of the community. Based on this, a protocol for an experimental study on those communities in the CIEA “El Limón” has been designed. In the protocol, we will obtain study areas with different density of A. pennatula by different logging treatments in early stages. The main objectives is to describe and compare the structure, the composition and the dynamics of the “carbonal” over time, and determine if there is a positive effect when density is modified. The results obtained from the protocol can be used as the basis to develop a management plan for “carbonales” in order to facilitate the Tropical Dry Forest’s restoration and forestry

Growth of juvenile Pinna nobilis in captivity conditions: Dietary and pathological constraints

The fan mussel, Pinna nobilis, is an endemic Mediterranean species, whose populations have been seriously affected by infectious diseases. The effect of diet composition on growth and survival rates, and on nutritional metrics including ingestion and absorption rates, together with food preferences were investigated in 48 juveniles. Individuals were initially acclimated to conditions of captivity with a mixed diet of three species of microalgae cultured in situ and riverine sediment. Then, they were changed to different diets based on combinations of commercial phytoplankton gels and riverine sediments except for a control group that was maintained under the acclimation conditions. Diet A consisted of Tetraselmis chuii; diet B on a 2 species mix of T. chuii and Isochrysis aff. galbana (T-ISO), diet C on a 3 species mix T. chuii, T-ISO and Phaeodactylum tricornatum, diet D on riverine sediment without microalgae, and diet E on T. chuii and riverine sediment. Individuals under experimental diets were fed ad libitum once per day and the water with food excess replaced before the next ration. The control diet showed the highest survival and growth (50% vs. 2.5% survival and ca. 6 mm vs. <1 mm shell growth· month−1), but rates were much lower than those of field animals (by ca. 30–40%). Mortality was ultimately associated to presence of Vibrio mediterranei, but our results suggest that diet quality is an important factor mediating host condition and disease resistance. Individuals fed sediments showed the lowest levels of nutritional performance, with higher ingestion (up to 5.5 times higher) and lower absorption rates (by approx. 60%), suggesting a poor adaptation to feed on detrital material. Additionally, individuals showed a significantly higher consumption of less voluminous microalgae (T-ISO and P.tricornatum) during food preference assays. The experimentation suggests that the development of new diets nutritionally similar to those available in the field and the finding of new food supplements promoting disease resistance is a research priority for the optimal maintenance of the species under long-term captivity conditions.info:eu-repo/semantics/acceptedVersio

Pinna nobilis in suboptimal environments are more tolerant to disease but more vulnerable to severe weather phenomena

We examined a disease outbreak of the fan mussel, Pinna nobilis (L.), in the Alfacs Bay (South Ebro Delta, Spain) during a period of two years in three zones exposed to a summer salinity gradient resulting from agricultural freshwater discharges and distance to the open sea. Long-term monitoring was also conducted in Fangar Bay (North Ebro Delta), featuring lower salinities and no evidence of disease. Results showed that the salinity gradient of Alfacs Bay (37.4–35.7) was associated to cumulative mortality (100% near the mouth, 43% in middle regions, and 13% in inner regions), thus hindering the spread of pathogens. Young specimens showed to be more tolerant to disease than large adults but become vulnerable over time. In Fangar Bay, lower salinities (30.5–33.5) prevented the disease but individuals were highly vulnerable to Storm Gloria which caused 60% mortality in 3 weeks, and ~100% in 6 weeks.info:eu-repo/semantics/acceptedVersio

Presence of Vibrio mediterranei associated to major mortality in stabled individuals of Pinna nobilis L

A major epizootic event attributed to Haplosporidium pinnae leading to 100% mortality of Pinna nobilis L. populations along Mediterranean coastlines started in the fall of 2016. As a result, a project to rescue 221 adult individuals of the endangered pen shell, Pinna nobilis was conducted in November 2017 in the two areas of the Spanish coast where the species was still abundant and apparently free from infection by H. pinnae: Port Lligat in the Costa Brava, and the Alfacs Bay in the Ebro Delta. For biosecurity reasons, the 106 individuals from the Ebro Delta were stabled at the IRTA facilities located next to Alfacs Bay, whereas the 115 individuals from Port Lligat were stabled in different institutions throughout the Spanish territory. Initial biopsies showed that individuals from the Ebro Delta were free of the parasite, whereas most individuals from Port Lligat were already parasitized and died in the following months. Individuals at IRTA were hold in five tanks and fed ca. 4% of their dry weight with a mix of three species of phytoplankton and fine riverine sediments (13% OM). Seawater was filtered through 10, 5 and 1 μm to ensure the absence of the parasite and disinfected with UV light. No individuals died during the 4 initial months of captivity, but two died in April–May at temperatures from 17 to 19 °C. A peak of mortalities occurred during the summer months and early fall (53%) with maximums coinciding with temperatures above 25 °C. Individuals were again analyzed by PCR and histology for the presence of H. pinnae, Mycobacteria sp., and other locally important pathogens of commercial bivalves (Vibrio splendidus, V. aestuarianus and Herpesvirus OsHV-1 microVar), and therefore considered as potential pathogens of pen shells. However, with the exception of 3 individuals that were positive for Mycobacteria sp., results were all negative for the studied pathogens. Microbiological culture and isolation of bacteria from three moribund individuals, sacrificed for study purposes, showed V. mediterranei as the dominant species, and further PCR analyses confirmed the presence of the bacterium in ten deceased individuals. Overall, our results suggest the V. mediterranei is an opportunistic pathogen of stabled individuals possibly subjected to stress from captivity, and that antibiotic treatment (Florfenicol) combined with vitamins and mineral supplementation and reduction of water temperature (15 to 18 °C), can be used to mitigate (not to eradicate) the disease. Further research is needed to determine diets and stabling conditions that minimize captivity stress and prevent the emergence of the disease.info:eu-repo/semantics/acceptedVersio