The future of the indigenous freshwater crayfish Austropotamobius italicus in Basque Country streams: Is it possible to survive being an inconvenient species?

The white-clawed freshwater crayfish Austropotamobius italicus is listed as “vulnerable” in the Spanish Red List of threatened species, but local legislation varies among Spanish regions. Thus, while in some places the species is classified as “in risk of extinction” and various plans of conservation and restoration have been implemented, in the Basque Country and other regions the species is not listed. The distribution of the white-clawed crayfish in the province of Biscay (Basque Country) was studied from 1993 to 2007 at more than 600 sampling locations. Results show that 108 streams were inhabited by the native crayfish species A. italicus while 137 streams were inhabited by non-native signal crayfish Pacifastacus leniusculus or red-swamp crayfish Procambarus clarkii. The spread of non-native crayfish is not the only threat to the native species whose survival is also closely dependent on how watersheds are managed. Most A. italicus populations inhabit headwaters, where forestry activities are very important. The presence of native crayfish in heavily forested areas results in a conflict of interests and makes its conservation particularly difficult. We employed a SWOT analysis – an assessment and decision tool commonly used in marketing and business – to evaluate the situation of the native white-clawed crayfish in Biscay, a province characterized by very high demographic pressure. SWOT analysis has proved to be a useful diagnostic tool and can help develop better and more accurate management strategies for the conservation of native crayfish threatened by multiple stressors

Cambios en las condiciones físicas, químicas y faunísticas de un sistema fluvial (río Oma, Bizkaia), y desaparición de una población de cangrejo autóctono (Austropotamobius pallipes) : ¿causa y/o efecto?

El Oma (cuenca del río Oka, provincia de Bizkaia) es un pequeño río relativamente poco alterado que recorre terrenos de uso forestal, agrícola y ganadero. En él habitaba una población bien establecida de cangrejo autóctono Austropotamobius pallipes, pero ésta había desaparecido en el verano de 1995, sin que se hubieran registrado mortandades masivas como las características de un episodio de afanomicosis. En este trabajo se estudia la evolución de las condiciones fisicoquímicas y de las comunidades bentónicas estivales del río Oma desde el año 1994 hasta el 2001, comparado esta dinámica respecto a las condiciones generales que presentan los hábitats de otras poblaciones de cangrejo autóctono en la red fluvial del entorno. Aparte de esta desaparición del cangrejo, también se han detectado cambios en algunas condiciones del agua así como en la composición faunística de la comunidad de macroinvertebrados. Se describen estos cambios temporales y se discuten sus posibles causas, especialmente la que ha generado la extinción de la especie protegida (influencia de depredadores, pérdida de calidad de hábitat por vertidos o lixiviados, intervenciones en cauce), pero aunque en otras cuencas cercanas se ha podido encontrar la causa principal de mortandad y/o desaparición de cangrejos, no así en el Oma, en donde podría haber tenido lugar una sinergia entre varios factores. No obstante, la evolución temporal del sistema río en los últimos años parece presentar una tendencia a recuperar las condiciones que tenía en el año 1994, tanto en la fisicoquímica como en la composición faunística.The Oma (Oka basin, province of Biscay) is a relatively little perturbed river, which runs through places where the main activities are forestry, agriculture and cattle raising. The native crayfish Austropotamobius pallipes was well established on it but in the summer of 1995 this population had disappeared. Crayfish mass mortalities that could have been due to the crayfish plague were not detected. The main objective of this work is to study the changes of abiotic and biotic summer conditions of the Oma River from 1994 to 2001. The Oma River conditions are compared with the general conditions of the close fluvial reaches inhabited by native crayfish. In addition to the disappearance of the crayfish population, changes in water chemistry and faunal composition of the benthic community were detected. Temporal variations are described in this work and the possible causes are also discussed, especially those related with the extinction of the protected species (predators' influence, decrease of the habitat quality by leaches, works on the riverbed). We have been able to detect the main cause for the mortality and/or disappearance of crayfish in other close fluvial zones, but not in the Oma River. In this stream it could have been due to the synergic interaction of several factors. However, the temporal evolution of the river system in the last years seems to show a trend to recover the conditions of the river on both physicochemical quality and faunal composition, that had in 1994

Monitoring and management of Pyrenean chamois in Aragon

8 páginasPeer reviewe

Veinte años de seguimiento poblacional de ungulados silvestres de Aragón

The remarkable increase of wild ungulates populations in Aragon during the last 50 years, both in numbers and distribution, has made population monitoring a need for effective management of these species. In parallel to their raising numbers, problems related to crop damage and collisions with vehicles are growing. In this situation there has been a shift in the management goals from conservation to population control. Different methods have been used in the surveys: postal enquiries for distribution, battues, distance sampling, night spotlight surveys and indirect ones based on transect and plot counts of pellet groups. Surveys started in 1985 for red deer, 1990 for wild boar and Iberian wild goat, 1995 for chamois and 2002 for roe deer, gradually becoming a population monitoring program. The surveys are carried out by rangers and wildlife consultants under the coordination and supervision of the Fish and Game Service of the Aragon Government. The ungulate populations are still growing (wild boar, wild goat, red and roe deer), are relatively stabilised (fallow deer, feral goat), fluctuate due to diseases (chamois) or show small populations limited to fenced states (Barbary sheep, mouflon). Hunting bags went from 1,100 to 36,000 during an eleven-year period (1990-2009): 303 chamois, 1,173 wild goats, 2,141 roe deer, 2,424 red deer and 29,595 wild boars, showing a trend which is still increasing. The main tool is therefore hunting quota and its verification through hunting bags declarations, damages to crops and car crashes, and population trend and abundance.La importante expansión de las poblaciones de ungulados silvestres en Aragón desde los años 50 del siglo XX hasta la actualidad, tanto en superficie ocupada como en abundancia de ejemplares, ha hecho necesario el seguimiento de las mismas para su adecuada gestión. Su incremento en las dos últimas décadas, junto con el importante aumento de daños agrícolas y colisiones con vehículos, ha motivado un importante cambio en los criterios gestores; pasando de la conservación y fomento al control e incluso reducción de efectivos. Los métodos utilizados para el seguimiento de las poblaciones fueron: encuestas quincenales de distribución, batidas, muestreos de distancia, captura – recaptura, fareos nocturnos y muestreos indirectos basados en el conteo de grupos de excrementos en transectos y parcelas fijas. Los seguimientos se comenzaron a realizar en 1985 en el caso del ciervo, 1990 en el jabalí y cabra montesa, 1995 en el sarrio y 2002 en el corzo, habiéndose convertido paulatinamente en una verdadera monitorización poblacional. Los seguimientos son realizados por Agentes de Protección de la Naturaleza del Gobierno de Aragón y asistencias técnicas externas, bajo la supervisión y coordinación de los responsables administrativos. Los resultados obtenidos muestran que, algunas poblaciones continúan su expansión e incremento (jabalí, ciervo, corzo, cabra montesa), otras se encuentran relativamente estabilizadas (gamo, cabra doméstica asilvestrada), y unas pocas fluctúan debido a enfermedades (sarrio) o muestran presencias testimoniales prácticamente reducidas a cercados (arruí, muflón). Las capturas declaradas han pasado de 1.100 a 36.000 en 11 años (1999-2009): 303 sarrios, 1.173 cabras montesas, 2.141 corzos, 2.424 ciervos y 29.595 jabalíes, con una tendencia al incremento que aún no ha finalizado. El instrumento fundamental por lo tanto son los cupos de caza y su verificación se realiza a partir de las declaraciones de capturas, los daños a la agricultura y accidentes automovilísticos y la tendencia y abundancia poblacional

Registry of the Spanish network for systemic sclerosis: survival, prognostic factors, and causes of death

Systemic sclerosis (SSc) is a rare, multisystem disease showing a large individual variability in disease progression and prognosis. In the present study, we assess survival, causes of death, and risk factors of mortality in a large series of Spanish SSc patients. Consecutive SSc patients fulfilling criteria of the classification by LeRoy were recruited in the survey. Kaplan-Meier and Cox proportional-hazards models were used to analyze survival and to identify predictors of mortality. Among 879 consecutive patients, 138 (15.7%) deaths were registered. Seventy-six out of 138 (55%) deceased patients were due to causes attributed to SSc, and pulmonary hypertension (PH) was the leading cause in 23 (16.6%) patients. Survival rates were 96%, 93%, 83%, and 73% at 5, 10, 20, and 30 years after the first symptom, respectively. Survival rates for diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc were 91%, 86%, 64%, and 39%; and 97%, 95%, 85%, and 81% at 5, 10, 20, and 30 years, respectively (log-rank: 67.63, P < 0.0001). The dcSSc subset, male sex, age at disease onset older than 65 years, digital ulcers, interstitial lung disease (ILD), PH, heart involvement, scleroderma renal crisis (SRC), presence of antitopoisomerase I and absence of anticentromere antibodies, and active capillaroscopic pattern showed reduced survival rate. In a multivariate analysis, older age at disease onset, dcSSc, ILD, PH, and SRC were independent risk factors for mortality. In the present study involving a large cohort of SSc patients, a high prevalence of disease-related causes of death was demonstrated. Older age at disease onset, dcSSc, ILD, PH, and SRC were identified as independent prognostic factors

Survival of natural populations of Austropotamobius pallipes in rivers in Bizkaia, Basque Country (North of Iberian Peninsula)

Some relict populations of the native crayfish Austropotamobius pallipes have been located in rivers in Bizkaia, (Basque Country, Spain), and its population numbers and dynamics, and habitat conditions have been studied for three years. The first descriptive results are given in this paper. The native crayfish populations must be considered residual because of the disrupted area distribution and highly fluctuating demography of the species. Up to now, the species has been located in more than thirty fluvial areas of relatively high slope and shallow and good quality water. Population characteristics (sex ratio, length and weight relations and length frequency classes) are studied in nineteen cases. Maximal relative population numbers are about 100 captures per hour ; these values are correlated to variables of conductivity, hardness, and concentrations of nitrates, nitrites, magnesium, potassium and ammonium. The degree of mineralization must reach a minimum level and, within the values found in the studied rivers, its increase favours the population of crayfish. Management measures to conserve native crayfish must include the protection and improvement of their habitat, prevention of access to it and to the commencement of a genetic study to palliate the phenomenon of endemism. It would also be highly recommendable to begin experimental restocking of riverbeds now without crayfish fauna and with apparently optimum conditions for the establishment of populations of autochthonous crayfish

Population structure and dynamics and habitat conditions of the native crayfish Austropotamobius pallipes in a pond : a case study in Basque Country (Northern Iberian Peninsula)

A natural and in appearance healthy population of the native crayfish Austropotamobius pallipes inhabiting a pond near Bilbao has been studied for three years, together with abiotic conditions of their habitat. The population occupies a littoral fringe (100 m length, 6 m width and approximately 1.5 m maximum depth), and has an estimated average density of 1.67 specimen/m2. Despite the very high conductivity of the water (all values are above 1,750 µS/cm), total net production in the period 94-96 was 2,571 . ± 460.0 g (4.3 ± 0.8 g/m2), with a productivity rate of 0.18 ± 0.04 measured as Production/Biomass (P/B) index. We think that population equilibrium with the carrying capacity of the pond ecosystem is reached

Survival of natural populations of Austropotamobius pallipes in rivers in Bizkaia, Basque Country (North of Iberian Peninsula)

Some relict populations of the native crayfish Austropotamobius pallipes have been located in rivers in Bizkaia, (Basque Country, Spain), and its population numbers and dynamics, and habitat conditions have been studied for three years. The first descriptive results are given in this paper. The native crayfish populations must be considered residual because of the disrupted area distribution and highly fluctuating demography of the species. Up to now, the species has been located in more than thirty fluvial areas of relatively high slope and shallow and good quality water. Population characteristics (sex ratio, length and weight relations and length frequency classes) are studied in nineteen cases. Maximal relative population numbers are about 100 captures per hour ; these values are correlated to variables of conductivity, hardness, and concentrations of nitrates, nitrites, magnesium, potassium and ammonium. The degree of mineralization must reach a minimum level and, within the values found in the studied rivers, its increase favours the population of crayfish. Management measures to conserve native crayfish must include the protection and improvement of their habitat, prevention of access to it and to the commencement of a genetic study to palliate the phenomenon of endemism. It would also be highly recommendable to begin experimental restocking of riverbeds now without crayfish fauna and with apparently optimum conditions for the establishment of populations of autochthonous crayfish

The future of the indigenous freshwater crayfish

The white-clawed freshwater crayfish Austropotamobius italicus is listed as “vulnerable” in the Spanish Red List of threatened species, but local legislation varies among Spanish regions. Thus, while in some places the species is classified as “in risk of extinction” and various plans of conservation and restoration have been implemented, in the Basque Country and other regions the species is not listed. The distribution of the white-clawed crayfish in the province of Biscay (Basque Country) was studied from 1993 to 2007 at more than 600 sampling locations. Results show that 108 streams were inhabited by the native crayfish species A. italicus while 137 streams were inhabited by non-native signal crayfish Pacifastacus leniusculus or red-swamp crayfish Procambarus clarkii. The spread of non-native crayfish is not the only threat to the native species whose survival is also closely dependent on how watersheds are managed. Most A. italicus populations inhabit headwaters, where forestry activities are very important. The presence of native crayfish in heavily forested areas results in a conflict of interests and makes its conservation particularly difficult. We employed a SWOT analysis – an assessment and decision tool commonly used in marketing and business – to evaluate the situation of the native white-clawed crayfish in Biscay, a province characterized by very high demographic pressure. SWOT analysis has proved to be a useful diagnostic tool and can help develop better and more accurate management strategies for the conservation of native crayfish threatened by multiple stressors

Modelling the habitat of a wild ungulate in a semi-arid Mediterranean environment in southwestern Europe: small cliffs are key predictors of the presence of Iberian wild goat

After a drastic contraction in the species' range, the Iberian wild goat Capra pyrenaica (Schinz, 1838) has recolonized semi-arid steppe areas where the availability of resources is lower than it is in the species typical habitat. There is a gap in the habitat characteristics that allow the species to survive in an environment that lacks high cliffs and rocky outcrops. We hypothesize that microhabitat characteristics allow the species to find the resources necessary for survival in atypical areas. To test that, we measured several topographic variables (slope, distance to small cliffs and elevation) as well as land use/cover variables (distance to bushes, forests, agriculture, artificial and rivers). To model the habitat in the Middle Ebro Valley, Spain, we used data from 7-yr of monitoring of the species in an averaged-model with Generalized Linear Mixed Model (GLMM-Logit). Distance to small cliffs and distance to bushes explained most of the variance in the model which reflected a fragmented potential habitat. The fragmented structure of the habitat which might act as a metapopulation system, and the spatial configuration of fragments along rivers might act as corridors that favour the dispersal should be taken in consideration in the conservation and management of the species.We also acknowledge funding from by the Spanish Ministry of Economy and Competitiveness (CGL2009-07301 and the FPI grant BES-2010-034151), and the Spanish Severo Ochoa Program (SEV-2012-0262)