Search

Population estimation implies considering the biology of the species, but also the constraints of logistic aspects such as cost. While common methods based on individual counts can provide precise estimates, they require an extensive sampling effort. An alternative to these methods is using cues linked to the species abundance. In that case, producing absolute estimates requires assessing the relationship between the individuals and these cues. In this paper, we propose a model based on data on spawning behaviour and Approximate Bayesian Computation to estimate the number of sea lamprey spawners using nest counts data. By counting the daily number of occupied nests and using parameters from a behavioural study, we set up a model simulating a spawning season and returning a population estimate by comparison with field data. Our model gives realistic estimates and we discuss the parameters on which to prioritize data collection with a sensitivity analysis, and show that halving the sample size provides a still satisfactory accuracy. We made an easily parametrizable application to run the model for any people interested in sea lamprey population estimation, and believe this framework to be a good way to increase data collection for both endangered and invasive sea lamprey.

Se cumple el 75 aniversario (1949-2024) del lanzamiento del primer volumen de la revista Munibe por parte de los fundadores de la Sociedad de Ciencias Aranzadi. Aprovechando la celebración de esta efeméride, en este trabajo se hace un breve repaso histórico de los acontecimientos más relevantes acaecidos durante este periodo, y las circunstancias que dieron lugar a la fundación en 1984 de la revista filial de Munibe donde se publican estas páginas: Munibe Ciencias Naturales. Durante los pasados 40 años, Munibe Ciencias Naturales ha publicado 484 artículos en 37 volúmenes, y aquí se analizan algunos datos bibliométricos generales de dichos trabajos. Este análisis revela la gran diversidad de contenidos que la revista ha acogido, aunque se observa que los trabajos zoológicos se están haciendo progresivamente más frecuentes en detrimento de los trabajos botánicos y, sobre todo, de los geológicos. Finalmente, se hacen algunas reflexiones sobre el alcance y propósitos de la revista, así como de las perspectivas de cara a su futuro. ABSTRACT: This year marks the 75th anniversary (1949-2024) of the publication of the first volume of the journal Munibe by the founders of the Aranzadi Scientific Society. On the occasion of this anniversary, this article offers a brief summary of the most relevant events that have occured during this period and the circumstances that led to the founding in 1984 of the sister publication in which this article is published: Munibe Natural Sciences. Over the last 40 years, Munibe Natural Sciences has published 484 papers in 37 volumes and this article analyses some of their general bibliometric data. It highlights the great diversity of the subject matter covered in this journal, although it may be observed that zoological papers are gradually becoming more frequent to the detriment of articles on botany and, especially, geology. Finally, this article concludes with a number of thoughts on the aims and scope of the journal, as well as some predictions about its future.

Many inland waters seasonally or permanently dry up, thus exposing sediments to the atmosphere. Here the authors show that a substantial amount of CO2 is emitted from these dry sediments, increasing current inland water carbon flux estimates by 6%.

Rivers are severely affected by human activities and many are simultaneously impacted by multiple stressors. Water diversion for hydropower generation affects ecosystem functioning of the bypassed reaches, which can alternate between periods with natural discharge and others with reduced flow that increase the surface of dry riverbeds. In parallel, urban pollution contributes a complex mixture of nutrients, organic matter, heavy metals, pesticides, and drugs, thus becoming an important stressor in rivers. However, there is little information on the interaction between both stressors on ecosystem functioning and, particularly, on organic matter processing, a key process linked to the input of energy to food webs. To assess the impact of water diversion and urban pollution on organic matter processing, we selected four rivers in a pollution gradient with a similar diversion scheme and compared reaches upstream and downstream from the diversion weirs. We measured leaf-litter decomposition and carbon dioxide (CO2) fluxes in both the wet channel and the dry riverbed. Water diversion and pollution in the wet channel did not affect CO2 fluxes but reduced microbial decomposition, whereas in the dry riverbed, their interaction reduced total and microbial decomposition and CO2 fluxes. Thus, both stressors affected organic matter processing stronger in dry riverbeds than in the wet channel. These results show that dry riverbeds must be taken into account to assess and manage the impacts of human activities on river ecosystems.

The habitat heterogeneity hypothesis states that increased habitat heterogeneity promotes species diversity through increased availability of ecological niches. We aimed at describing the local-scale (i.e. nest and adjacent substrate) effects of nests of the sea lamprey (Petromyzon marinus L.) as ecosystem engineer on macroinvertebrate assemblages. We hypothesized that increased streambed physical heterogeneity caused by sea lamprey spawning would modify invertebrate assemblages and specific biologic traits and promote reach-scale diversity. We sampled thirty lamprey nests of the Nive River, a river of the south western France with a length of 79.3 km and tributary of the Adour River, in three zones: the unmodified riverbed (upstream) and zones corresponding to the nest: the area excavated (pit) and the downstream accumulation of pebbles and cobbles (mound). The increased habitat heterogeneity created by lamprey was accompanied by biological heterogeneity with a reduced density of invertebrates (3777 ± 1332 individuals per m2 in upstream, 2649 ± 1386 individuals per m2 in pit and 3833 ± 1052 individuals per m2 in mound) and number of taxa (23.5 ± 3.9 taxa for upstream, 18.6 ± 3.9 taxa in pit and 21.2 ± 4.5 taxa for mound) in the pit compared to other zones. However the overall taxa diversity in nest increased with 82 ± 14 taxa compared to the 69 ± 8 taxa estimated in upstream zone. Diversity indices were consistent with the previous results indicating a loss of α diversity in pit but a higher β diversity between a pit and a mound than between two upstream zones, especially considering Morisita index accounting for taxa abundance. Trait analysis showed high functional diversity within zones with a reduced proportion of collectors, scrapers, shredders, litter/mud preference and small invertebrates in mound, while the proportion of “slabs, blocks, stones and pebbles” preference and largest invertebrates increased. Pit presented the opposite trend, while upstream had globally intermediate trait proportions. Our results highlight important effects on species and functional diversity due to habitat heterogeneity created by a nest-building species, what can ultimately influence food webs and nutrient processes in river ecosystems.

Discharge reduction, as caused by water diversion for hydropower, and fine sediments deposition, are prevalent stressors that may affect multiple ecosystem functions in streams. Periphytic biofilms play a key role in stream ecosystem functioning and are potentially affected by these stressors and their interaction. We experimentally assessed the interactive effects of discharge and fine sediments on biofilm metabolism in artificial indoor channels using a factorial split-plot design with two explanatory variables: water discharge (20, 39, 62, 141 and 174 cm3 s-1) and fine sediments (no sediment or 1100 mg L-1 of sediments). We incubated artificial tiles for 25 days in an unpolluted stream to allow biofilm colonization, and then placed them into the indoor channels for acclimation for 18 days. Subsequently, we manipulated water discharge and fine sediments and, after 17 days, we measured biofilm chlorophyll-a concentration and metabolism. Water velocity (range, 0.5 to 3.0 cm s-1) and sediment deposition (range, 6.1 to 16.6 mg cm-2) increased with discharge, the latter showing that the effect of increased inputs prevailed over sloughing. In the no-sediment treatments, discharge did not affect biofilm metabolism, but reduced chlorophyll-a. Sediments, probably as a consequence of nutrients released, promoted metabolism of biofilm and chlorophyll-a, which became independent of water discharge. Our results indicate that pulses of fine sediments can promote biofilm algal biomass and metabolism, but show interactive effects with discharge. Although discharge reduction can affect the abundance of basal resources for food webs, its complex interactions with fine sediments make it difficult to forecast the extent and direction of the changes.

Las plantaciones de eucalipto (género Eucalyptus) tienen una amplia distribución a escala global y causan preocupación por los efectos que pueden ocasionar sobre el medio ambiente. En este trabajo revisamos la evolución de la superficie cubierta por los eucaliptos en Euskadi y evaluamos sus efectos ambientales a partir de la bibliografía científica existente sobre esta región y sobre la península ibérica. Entre 1986 y 2019, la superficie de plantaciones de eucaliptos se ha cuadruplicado, pasando de 4.866 a 19.643 ha, proceso este que está acelerándose a causa de la plaga de la banda marrón del pino. Los estudios publicados muestran de manera sistemática que las plantaciones de eucaliptos en Euskadi y el resto de la Península tienen un efecto medioambiental negativo si se compara con las plantaciones de pino y, especialmente, con los bosques nativos. Las plantaciones de eucalipto modifican las características del suelo y disminuyen la biodiversidad. Entre los organismos más afectados se encuentran los hongos, líquenes, plantas herbáceas, anfibios, aves e invertebrados acuáticos. También se detectan alteraciones en el funcionamiento del ecosistema, en procesos como la descomposición de hojarasca. Aunque algunas afecciones parecen ser consecuencia de la intensidad con la que se explotan estas plantaciones y podrían reducirse mediante medidas correctoras, otros efectos parecen guardar relación con las características intrínsecas del eucalipto que, en consecuencia, no pueden modificarse. Es previsible que la magnitud de los impactos se agrave conforme se incremente la superficie cubierta por eucaliptales así como el número de rotaciones en sus explotaciones. ___________________________________________ Abstract Eucalyptus plantations are widely distributed throughout the world, thus creating concern due to their potential environmental effects. In this work we analyse the evolution of the coverage of eucalypts in the Basque Country and assess their environmental effects based on the scientific literature from this region and from the Iberian Peninsula. From 1986 to 2019 the area covered by eucalypt plantations increased fourfold, from 4,866 to 19,643 ha, a process that is accelerating as a consequence of the pine needle blight. The research so far published shows systematically that eucalypt plantations in the Basque Country and in the rest of the peninsula have detrimental environmental effects, compared to pine plantations and, especially, to native forests. Eucalypt plantations alter soil characteristics and reduce biodiversity. Fungi, lichens, herbaceous plants, amphibians, birds and aquatic invertebrates are among the most seriously affected groups of organisms. Ecosystem processes, such as leaf-litter breakdown, are also affected. Some of these effects seem to be a consequence of the intensity of exploitation in these plantations and, thus, could be reduced by means of improved management; other effects seem to relate to the intrinsic characteristics of the eucalypts, which cannot be modified. The magnitude of the impacts will likely increase with the area covered by eucalypt plantations, as well as with the number of crop rotations.

Abstract Background Progressive encephalomyelitis with rigidity and myoclonus (PERM) syndrome is a rare neurological condition. Its clinical characteristics include axial and limb muscle rigidity, myoclonus, painful spasms and hyperekplexia. Diagnosis of this disease can be very challenging and optimal long-term treatment is unclear. Case presentation We report a case of a 62 year old patient admitted for repetitive myoclonus and rigidity in the lower limbs progressing since 10 years, associated with a fluctuating encephalopathy requiring stays in Intensive Care Unit. Multiple diagnostics and treatment were proposed, unsuccessfully, before the diagnosis of PERM syndrome was established. In association with the clinical presentation, a strong positive result for GAD (glutamic acid decarboxylase) antibodies lead to the diagnosis of PERM syndrome. Conclusions PERM syndrome is a rare disease and its diagnosis is not easy. Once the diagnosis is established, the correct treatment should follow and could be lifesaving, regardless of a delayed diagnosis. Maintenance of long-term oral corticotherapy is suggested to prevent relapses.