Colonization and development of Oribatida mite communities (Acari: Oribatida) in the forest reclaimed limestone mine dumps

In order to study the colonization and development of moss mites (Oribatida) communities in a Scots pine forest of a reclaimed limestone mine dump in Northern Poland, 3 plots from the dump were chosen. The selected plots differed in age, 5 years old, 35 and 50 years old. From a total of 30 samples 499 mites (Acari) were extracted in Tullgren funnel from which 262 were Oribatida. Abundance (N) was analyzed in all mites and after determining the species of both, juvenile and adult stages of oribatids, the following indices were analyzed: Abundance (N), Dominance (D), Species diversity (S), Species richness (s) and Shannon’s diversity index (H). Regarding to the results obtained; oribatid mites were dominant with the highest abundance in all assemblages (Plot 1: 139 Oribatida /299 Acari. Plot 2: 40/55 and Plot 3: 83/145). Tectocepheus velatus showed a very high dominance (45,99%) in plot 1; the highest value for Shannon’s diversity index belonged to plot 3. On the other hand, juvenile’s percentage was significantly higher than adult’s percentage, especially at plot 2 (95,02%). These results made us to conclude that the high abundance of oribatids in the youngest forest is due to T. velatus’s high abundance and that plot 3 is the best habitat for mites. Finally, the high occurrence of juvenile stages requires keeping on studying the area.

Biotic vs. Abiotic Control of Decomposition: A Comparison of the Effects of Simulated Extinctions and Changes in Temperature

The loss of species is known to have significant effects on ecosystem functioning, but only recently has it been recognized that species loss might rival the effects of other forms of environmental change on ecosystem processes. There is a need for experimental studies that explicitly manipulate species richness and environmental factors concurrently to determine their relative impacts on key ecosystem processes such as plant litter decomposition. It is crucial to understand what factors affect the rate of plant litter decomposition and the relative magnitude of such effects because the rate at which plant litter is lost and transformed to other forms of organic and inorganic carbon determines the capacity for carbon storage in ecosystems and the rate at which greenhouse gasses such as carbon dioxide are outgassed. Here we compared how an increase in water temperature of 5 degrees C and loss of detritivorous invertebrate and plant litter species affect decomposition rates in a laboratory experiment simulating stream conditions. Like some prior studies, we found that species identity, rather than species richness per se, is a key driver of decomposition, but additionally we showed that the loss of particular species can equal or exceed temperature change in its impact on decomposition. Our results indicate that the loss of particular species can be as important a driver of decomposition as substantial temperature change, but also that predicting the relative consequences of species loss and other forms of environmental change on decomposition requires knowledge of assemblages and their constituent species' ecology and ecophysiology.

SYSTEMATICS OF GROUNDWATER OLIGOCHAETES (ANNELIDA, CLITELLATA) IN KARSTIC AREAS OF THE CANTABRIAN REGION/ ERREGIO KANTAURIARREKO EREMU KARSTIKOETAN DAUDEN LURPEKO OLIGOKETO (ANNELIDA, CLITELLATA) URT

This thesis deals with the oligochaete taxa (Annelida, Clitellata) from several karst units in the Cantabrian region, northern Iberian Peninsula. Groundwater oligochaetes are still poorly known fauna and the area seems to be a promising hotspot for groundwater taxa. Metodology is based on both morphological and molecular analyses. More than 7,000 specimens were collected from five karst units and >60 taxa were identified. Stygobiont oligochaete fauna in the northern Iberian Peninsula is diverse and mostly endemic (range areas <300 km). Three new stygogiont oligochaete species are described: Gianius navarroi Rodriguez & Achurra, 2010, Isochaetides gianii Rodriguez & Achurra, 2010 and Troglodrilus jugeti Achurra et al., 2012; and another four new taxa will be described in the near future. Taxonomic remarks on Lophochaeta ignota Stolc, 1886 and Troglodrilus galarzai (Giani & Rodriguez, 1988) are provided. The controversial separation of L. ignota and Heterochaeta costata Claparède, 1863 from Tubifex Lamarck, 1816 is corroborated by mitochondrial molecular data. Following the DNA barcoding method, individuals of the stygoxene species Stylodrilus heringianus Claparède, 1862 from different geographic areas are shown to represent a single metapopulation. The first phylogenetic analysis of the subfamily Tubificinae based on molecular data is attemped, which although incompletely resolved, evidences for the first time a close relationship between a stygobiont oligochaete (Troglodrilus Juget et al. 2006) and an estuarine especies (Heterochaeta costata Claparéde, 1863). A marine ancestor is hypothesised for Troglodrilus. Finally, Ereñozar karst unit (Biscay) is suggested to be a hotspot for groundwater oligochaetes (11 stygobiont taxa, of which 4 are endemic to the karst unit) and several biodiversity indices (Species richness, Rarity, Vulnerability and Complementarity) are shown to be useful tools for conservation management of groundwater habitats in that karst area.

Valoración del estado ecológico de la costa rocosa de Urdaibai (Bizkaia), mediante el estudio de fitobentos intermareal

Dentro de las medidas protectoras sobre la Reserva de la Biosfera de Urdaibai se encuentra el EDAR (Estación Depuradora de Aguas Residuales) de Lamiaran (Bermeo), que entrará en funcionamiento próximamente (otoño 2014). Para evaluar su impacto sobre el medio costero, el presente estudio realiza una primera valoración del estado ecológico de la costa abierta de la reserva mediante diversos parámetros del fitobentos intermareal. Se estableció una red de muestreo compuesta por dos localidades impactadas y cuatro control. En cada localidad se eligieron aleatoriamente dos estaciones y se muestrearon dos niveles en la zona intermareal inferior. Las localidades impactadas por aguas residuales reflejaban valores bajos de riqueza específica, cobertura, diversidad y cobertura de perennes junto a una mayor abundancia de especies estacionales de morfología simple. Sin embargo los análisis estadísticos no detectaron diferencias significativas entre ambos grupos de localidades (impactadas vs control) detectando únicamente diferencias significativas a nivel de estación, debido en gran medida al efecto de la dispersión de las unidades muestrales para los parámetros estudiados.

Community Turnover of Wood-Inhabiting Fungi across Hierarchical Spatial Scales

For efficient use of conservation resources it is important to determine how species diversity changes across spatial scales. In many poorly known species groups little is known about at which spatial scales the conservation efforts should be focused. Here we examined how the community turnover of wood-inhabiting fungi is realised at three hierarchical levels, and how much of community variation is explained by variation in resource composition and spatial proximity. The hierarchical study design consisted of management type (fixed factor), forest site (random factor, nested within management type) and study plots (randomly placed plots within each study site). To examine how species richness varied across the three hierarchical scales, randomized species accumulation curves and additive partitioning of species richness were applied. To analyse variation in wood-inhabiting species and dead wood composition at each scale, linear and Permanova modelling approaches were used. Wood-inhabiting fungal communities were dominated by rare and infrequent species. The similarity of fungal communities was higher within sites and within management categories than among sites or between the two management categories, and it decreased with increasing distance among the sampling plots and with decreasing similarity of dead wood resources. However, only a small part of community variation could be explained by these factors. The species present in managed forests were in a large extent a subset of those species present in natural forests. Our results suggest that in particular the protection of rare species requires a large total area. As managed forests have only little additional value complementing the diversity of natural forests, the conservation of natural forests is the key to ecologically effective conservation. As the dissimilarity of fungal communities increases with distance, the conserved natural forest sites should be broadly distributed in space, yet the individual conserved areas should be large enough to ensure local persistence.

Biotic vs. Abiotic Control of Decomposition: A Comparison of the Effects of Simulated Extinctions and Changes in Temperature

The loss of species is known to have significant effects on ecosystem functioning, but only recently has it been recognized that species loss might rival the effects of other forms of environmental change on ecosystem processes. There is a need for experimental studies that explicitly manipulate species richness and environmental factors concurrently to determine their relative impacts on key ecosystem processes such as plant litter decomposition. It is crucial to understand what factors affect the rate of plant litter decomposition and the relative magnitude of such effects because the rate at which plant litter is lost and transformed to other forms of organic and inorganic carbon determines the capacity for carbon storage in ecosystems and the rate at which greenhouse gasses such as carbon dioxide are outgassed. Here we compared how an increase in water temperature of 5 degrees C and loss of detritivorous invertebrate and plant litter species affect decomposition rates in a laboratory experiment simulating stream conditions. Like some prior studies, we found that species identity, rather than species richness per se, is a key driver of decomposition, but additionally we showed that the loss of particular species can equal or exceed temperature change in its impact on decomposition. Our results indicate that the loss of particular species can be as important a driver of decomposition as substantial temperature change, but also that predicting the relative consequences of species loss and other forms of environmental change on decomposition requires knowledge of assemblages and their constituent species' ecology and ecophysiology