Fingerprints of environmental change on the rare mediterranean flora: a 115-year study

We empirically assessed the long‐term changes in the rare species assemblage of a Mediterranean flora, in terms of species life history traits, niche and biogeographic features, and taxonomic groups. We used a 115‐year historical record of ca. 2100 plant species occurrences in a 6250 km² region in Mediterranean France. Species were assigned to two classes of regional abundance for the years 1886 and 2001 (rare species, i.e. exhibiting one or two occurrences vs. nonrare species), and to three classes of abundance changes during 1886–2001 (decreasing/extinct, stable, increasing/immigrant). Then, we tested whether species regional abundance and species abundance change were related to their morphological and life‐history traits (life form, perenniality, height, dispersal agent, pollination mode), niche and biogeographic features (habitat specialization, level of endemism, biogeographic origin) and taxonomic group. The regional assemblage of rare species was not biologically random and significantly changed between 1886 and 2001. Species classified as rare in 1886 had a significantly higher rate of extinction in the study region during 1886–2001. The highest rate of regression/extinction was found among hydrophyte and/or water‐dispersed rare species, and among annual rare species. However, herbaceous perennial, tree and wind‐dispersed rare species significantly increased in abundance during 1886–2001. Rare species with Eurosiberian distributions, occurring at the southern margin of their range in the study region, dramatically declined or went extinct in the region during 1886–2001; whereas rare species with Mediterranean affinities remained significantly stable. We also found strong evidence for taxonomic patterns in species abundance and abundance changes from 1886 to 2001. The long‐term biological changes documented here in the rare species assemblage of a Mediterranean flora are consistent with the predicted consequences of climate and land use changes currently occurring in the Mediterranean Basin. With the potential decline or even extinction of entire taxa and the loss of southern ecotypes of widespread Eurosiberian species, both evolutionary history and speciation potential of the Mediterranean Region could be strongly altered in future decades.     

Defining phytoclimatic units in Galicia,Spain, by means of multivariate methods

Abstract. Floristic and climate data from 150 plots in 25 sites in Galicia, Spain, were analysed to test the hypothesis that climate is the major factor governing the distribution of woody plant species. TWINSPAN classification, Detrended Correspondence Analysis and Canonical Correspondence Analysis were applied in successive stages of the data analysis to describe vegetational variation in relation to climatic gradients. Six groups of species were defined, two clearly oceanic (Maritime and Cool Maritime), one mediterranean maritime, and three mediterranean (Cold Mediterranean, Cool Mediterranean and Temperate Mediterranean). An aridity gradient was revealed as the primary factor regulating the distribution of the species considered. This main gradient reflects the transition between the Eurosiberian and Mediterranean bio-geographic regions. The gradient can be characterized by means of the Vernet bioclimatic index. A value ≥ 4 for this index can be taken to define the mediterranean zone in our study area. The mean minimum temperature in the coldest month was the second most influential climatic variable. Partial ordination analysis revealed that the residual variation was insignificant and that the observed variation in vegetation can be fully accounted for by climatic variables.     

Adding complexity to the complex: new insights into the phylogeny, diversification and origin of parthenogenesis in the Aporrectodea caliginosa species complex (Oligochaeta, Lumbricidae)

The importance of the Aporrectodea caliginosa species complex lies in the great abundance and wide distribution of the species which exist within it. For more than a century, chaos has surrounded this complex; morphological criteria has failed to solve the taxonomic status of these species. This present body of work aims to study the phylogeny of this complex by increasing the number of samples used in previous molecular works and by including morphologically-similar species that were never studied using molecular tools (A. giardi, Nicodrilus monticola, N. carochensis and N. tetramammalis). Two basal clades were obtained: one formed by A. caliginosa and A. tuberculata and the other by the rest of the species. This second clade was divided into two more: one with Eurosiberian and another with Mediterranean forms. A. caliginosa and A. longa were divided into two paraphyletic groups. Both A. giardi and A. nocturna showed characteristics consistent with monophyletic groups. Each of the two recovered lineages of A. trapezoides were phylogenetically related to different sexual species. While lineage I of A. trapezoides was monophyletic, lineage II resulted to be paraphyletic, as well as the three Nicodrilus 'species'. The diversification of the complex occurred during the Late Miocene-Early Pliocene (6.92-11.09 Mya). The parthenogenetic forms within the Mediterranean clade would have diversified before the ones in the Eurosiberian clade (3.13-4.64 Mya and 1.05-3.48 Mya, respectively), thus implying the existence not only of at least two different moments in which parthenogenesis arose within this complex of species, but also of two different and independent evolutionary lines. Neither the 4× rule nor the GMYC method for species delimitation were successful for distinguishing taxonomically-distinct species.     

Identification of current ecosystem functional types in the Iberian Peninsula

Aim To examine the geographical patterns of the interception of photosynthetically active radiation by vegetation and to describe its spatial heterogeneity through the definition of ecosystem functional types (EFTs) based on the annual dynamics of the Normalized Difference Vegetation Index (NDVI), a spectral index related to carbon gains. Location The Iberian Peninsula. Methods EFTs were derived from three attributes of the NDVI obtained from NOAA/AVHRR sensors: the annual integral (NDVI‐I), as a surrogate of primary production, an integrative indicator of ecosystem functioning; and the intra‐annual relative range (RREL) and month of maximum NDVI (MMAX), which represent key features of seasonality. Results NDVI‐I decreased south‐eastwards. The highest values were observed in the Eurosiberian Region and in the highest Mediterranean ranges. Low values occurred in inner plains, river basins and in the southeast. The Eurosiberian Region and Mediterranean mountains presented the lowest RREL, while Eurosiberian peaks, river basins, inner‐agricultural plains, wetlands and the southeastern part of Iberia presented the highest. Eurosiberian ecosystems showed a summer maximum of NDVI, as did high mountains, wetlands and irrigated areas in the Mediterranean Region. Mediterranean mountains had autumn–early‐winter maxima, while semi‐arid zones, river basins and continental plains had spring maxima. Based on the behaviour in the functional traits, 49 EFTs were defined. Main conclusions The classification, based on only the NDVI dynamics, represents the spatial heterogeneity in ecosystem functioning by means of the interception of radiation by vegetation in the Iberian Peninsula. The patterns of the NDVI attributes may be used as a reference in evaluating the impacts of environmental changes. Iberia had a high spatial variability: except for biophysically impossible combinations (high NDVI‐I and high seasonality), almost any pattern of seasonal dynamics of radiation interception was represented in the Peninsula. The approach used to define EFTs opens the possibility of monitoring and comparing ecosystem functioning through time.     

The non-omphalinoid species of Arrhenia in the Iberian Peninsula

A taxonomic study of the species with nutant, pleurotoid and cyphelloid basidiomata of the genus Arrhenia in the Iberian Peninsula is presented. This study is based on the examination of recent specimens collected in the field and from dried herbarium collections. Five species and one variety of this genus are recognized on the basis of morphological and ecological features: Arrhenia acerosa var. acerosa, A. acerosa var. tenella, A. auriscalpium, A. lobata, A. retiruga and A. spathulata. Arrhenia auriscalpium is new to Spain, where it is not restricted to alpine zones of the Eurosiberian region and is more common in the Mediterranean region than previously reported. In contrast, A. acerosa var. tenella currently is known from the Eurosiberian subalpine belt and represents the first report to the Iberian Peninsula, and A. retiruga is known only from the mesomediterranean to supramediterranean belts of the Mediterranean region. Arrhenia acerosa var. acerosa, A. lobata and A. spathulata are widespread in both the Eurosiberian and the Mediterranean regions. Non-Iberian materials of A. acerosa var. tenella and A. spathulata also were studied for comparison. Cyphella cochlearis var. subsessilis, Dictyolus lagunae, Leptoglossum muscigenum var. azonum and Pleurotellus acerosus var. tenellus are lectotypified. Cyphella cochlearis var. subssesilis, Dictyolus lagunae and Leptoglossum muscigenum var. azonum are synonymized with Arrhenia spathulata, and Cyphella cochlearis var. auriformis is placed in synonymy with A. auriscalpium. These taxa are illustrated, described and discussed, based on Iberian material with emphasis on features of the basidioma, pigment of the pileipellis, presence or absence of clamps and shape and size of the basidiospores. A diagnostic key also is given.     

Late Würm and early Holocene in the mountains of northwest Iberia: biostratigraphy,chronology and tree colonization

Northwest Iberia (Spain and Portugal) is a large and complex territory which is currently considered a contact border between two different biogeographical regions, the Eurosiberian and the Mediterranean. Such complexity is clearly influenced by several main factors, namely the winding mountain ranges of this region and their position on the peninsula, which result in several markedly different environments coexisting within distances of only a few kilometres apart, such as extremely oceanic or continental climates and high mountain areas or inland basins. This intricacy might also be reflected in the postglacial palaeoecological reconstructions which have been made for different mountain areas of northwest Iberia. Several isolated pollen diagrams from key sites in the area which have been published during the last decades have been questioned, because they show tendencies or chronologies apparently incompatible with global dynamics affecting the North Atlantic. In this paper we explore the possible integration of the biostratigraphies and chronologies of several selected pollen sites in this region. Northwest Iberia as a whole has been firstly divided into several more homogeneous biogeographical units, and high quality pollen sequences from each unit were selected to obtain reconstructions of local dynamics at each site and also approximations of the regional tendencies in each unit. Subsequently, the correlation between the different regional tendencies and their coherence in relation to the global climatic models performed for the North Atlantic is discussed.     

Forest composition in Mediterranean mountains is projected to shift along the entire elevational gradient under climate change

Aim Species distribution models have been used frequently to assess the effects of climate change on mountain biodiversity. However, the value and accuracy of these assessments have been hampered by the use of low‐resolution data for species distributions and climatic conditions. Herein we assess potential changes in the distribution and community composition of tree species in two mountainous regions of Spain under specific scenarios of climate change using data with a high spatial resolution. We also describe potential changes in species distributions and tree communities along the entire elevational gradient. Location Two mountain ranges in southern Europe: the Central Mountain Range (central west of the Iberian Peninsula), and the Iberian Mountain Range (central east). Methods We modelled current and future distributions of 15 tree species (Eurosiberian, sub‐Mediterranean and Mediterranean species) as functions of climate, lithology and availability of soil water using generalized linear models (logistic regression) and machine learning models (gradient boosting). Using multivariate ordination of a matrix of presence/absence of tree species obtained under two Intergovernmental Panel on Climate Change (IPCC) scenarios (A2 and B2) for two different periods in the future (2041–70 and 2071–2100), we assessed the predicted changes in the composition of tree communities. Results The models predicted an upward migration of communities of Mediterranean trees to higher elevations and an associated decline in communities of temperate or cold‐adapted trees during the 21st century. It was predicted that 80–99% of the area that shows a climate suitable for cold–wet‐optimum Eurosiberian coniferous and broad‐leaved species will be lost. The largest overall changes were predicted for Mediterranean species found currently at low elevations, such as Pinus halepensis, Pinus pinaster, Quercus ilex ssp. ballota and Juniperus oxycedrus, with sharp increases in their range of 350%. Main conclusions It is likely that areas with climatic conditions suitable for cold‐adapted species will decrease significantly under climate warming. Large changes in species ranges and forest communities might occur, not only at high elevations within Mediterranean mountains but also along the entire elevational gradient throughout this region, particularly at low and mid‐elevations. Mediterranean mountains might lose their key role as refugia for cold‐adapted species and thus an important part of their genetic heritage.     

Genetic differentiation and secondary contact zone in the seagrass Cymodocea nodosa across the Mediterranean–Atlantic transition region

Aim A central question in evolutionary ecology is the nature of environmental barriers that can limit gene flow and induce population genetic divergence, a first step towards speciation. Here we study the geographical barrier constituted by the transition zone between the Atlantic Ocean and the Mediterranean Sea, using as our model Cymodocea nodosa, a seagrass distributed throughout the Mediterranean and in the Atlantic, from central Portugal to Mauritania. We also test predictions about the genetic footprints of Pleistocene glaciations. Location The Atlantic–Mediterranean transition region and adjacent areas in the Atlantic (Mauritania to south‐west Portugal) and the Mediterranean. Methods We used eight microsatellite markers to compare 20 seagrass meadows in the Atlantic and 27 meadows in the Mediterranean, focusing on the transition between these basins. Results Populations from these two regions form coherent groups containing several unique, high‐frequency alleles for the Atlantic and for the Mediterranean, with some admixture west of the Almeria–Oran Front (Portugal, south‐west Spain and Morocco). These are populations where only one or a few genotypes were found, for all but Cadiz, but remarkably still show the footprint of a contact zone. This extremely low genotypic richness at the Atlantic northern edge contrasts with the high values (low clonality) at the Atlantic southern edge and in most of the Mediterranean. The most divergent populations are those at the higher temperature range limits: the southernmost Atlantic populations and the easternmost Mediterranean, both potential footprints of vicariance. Main conclusions A biogeographical transition region occurs close to the Almeria–Oran front. A secondary contact zone in Atlantic Iberia and Morocco results from two distinct dispersal sources: the Mediterranean and southernmost Atlantic populations, possibly during warmer interglacial or post‐glacial periods. The presence of high‐frequency diagnostic alleles in present‐day disjunct populations from the southernmost Atlantic region indicates that their separation from all remaining populations is ancient, and suggests an old, stable rear edge.     

Pentaschistis (Poaceae) diversity in the Cape mediterranean region: habitat heterogeneity and climate stability

Aim To evaluate the role of habitat heterogeneity on species richness and turnover in the mega species‐rich Cape Floristic Region (Cape), the mediterranean region of southern Africa. Location The Cape and Drakensberg regions of southern Africa. Methods Bioclimatic data were used to estimate habitat amount and habitat heterogeneity in the Cape and Drakensberg regions; these data were then used to explain the patterns of species diversity in the Pentaschistis clade (Poaceae) in these two regions. Habitat variables were used to create ‘bioclimatic units’ to characterize 1′× 1′ cells in southern Africa and to describe the niches of species. Using these bioclimatic units, the niche and range sizes of species in the two regions were compared. A phylogram was used to test for age and lineage effects. Results Pentaschistis species diversity and turnover are higher in the Cape than the Drakensberg. There is no significant difference in the habitat amount and heterogeneity between the two regions. Species occupy the same range of estimated niche sizes, yet there are significantly more range‐restricted Pentaschistis species in the Cape. Main conclusions The roles of age‐ and lineage‐related effects are rejected; biodiversity differences lie in the regions. Current macrohabitat does not explain the differences in biodiversity between the two regions. The larger number of range‐restricted species in the Cape cannot be explained by dispersal mechanism or the occupation of range‐restricted habitats. Species of Pentaschistis and other Cape clades share characteristics associated with species from historically climatically stable areas, and palaeoclimatic and palaeontological evidence indicates the Cape climate has been more stable than the Drakensberg climate throughout the Pleistocene. We conclude that the corresponding lack of extinction might have allowed an accumulation of species in the Cape. Similar climatic and biological evidence for the south‐west Australian Floristic and Mediterranean regions indicate that the same mechanism might explain the high species richness of these mediterranean regions.     

Influences of ecology and biogeography on shaping the distributions of cryptic species: three bat tales in Iberia

To determine what shapes the distributions of cryptic species, we aimed to unravel ecological niches and geographical distributions of three cryptic bat species complexes in Iberia, Plecotus auritus/begognae, Myotis mystacinus/alcathoe and Eptesicus serotinus/isabellinus (with 44, 69, 66, 27, 121 and 216 records, respectively), considering ecological interactions and biogeographical patterns. Species distribution models (SDMs) were built using a presence‐only technique (Maxent), incorporating genetically identified species records with environmental variables (climate, habitat, topography). The most relevant variables for each species’ distribution and respective response curves were then determined. SDMs for each species were overlapped to assess the contact zones within each complex. Niche analyses were performed using niche metrics and spatial principal component analyses to study niche overlap and breadth. The Plecotus complex showed a parapatric distribution, although having similar biogeographical affinities (Eurosiberian), possibly explained by competitive exclusion. The Myotis complex also showed Eurosiberian affinities, with high overlap between niches and distribution, suggesting resource partitioning between species. Finally, E. serotinus was associated with Eurosiberian areas, while E. isabellinus occurred in Mediterranean areas, suggesting possible competition in their restricted contact zone. This study highlights the relevance of considering potential ecological interactions between similarly ecological species when assessing species distributions. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 ,150–162.     

Glutathione S-transferases in earthworms (Lumbricidae).

Glutathione S-transferase activity (EC 2.5.1.18) was demonstrated in six species of earthworms of the family Lumbricidae: Eisenia foetida, Lumbricus terrestris, Lumbricus rebellus, Allolobophora longa, Allolobophora caliginosa and Allolobophora chlorotica. Considerable activity was obtained with 1-chlorl-2,4-dinitrobenzene and low activity with 3,4-dichloro-1-nitrobenzene, but no enzymic reaction was detectable with sulphobromophthalein 1,2-epoxy-3-(p-nitrophenoxy)propane of trans-4-phenylbut-3-en-2-one as substrates. Enzyme prepartations from L. rubellus and A. longa were the most active, whereas A. chlorotica gave the lowest activity. The ratio of the activities obtained with 1-chloro-2,4-dinitrobenzene and 3,4-cichloro-1-nitrobenzene was very different in the various species, but no phylogenetic pattern was evident. Isoelectric focusing gave rise to various activity peaks as measured with 1-chloro-2,4-dinitrobenzene as a substrate, and the activity profiles of the species examined appeared to follow a taxonomic pattern. The activity of Allolobophora had the highest peak in the alkaline region, whereas that of Lumbricus had the highest peak in the acid region. Eisenia showed a very complex activity profile, with the highest peak ne pH 7. As determined by an enzymic assay, all the species contained glutathione, on an average about 0.5 mumol/g wet wt. Conjugation with glutathione catalysed by glutathione S-transferases may consequently be an important detoxification mechanism in earthworms.     

Environmental and human factors influencing rare plant local occurrence, extinction and persistence: a 115-year study in the Mediterranean region

Aim Assessing whether environmental and human factors influenced the spatial distribution and the dynamics of regionally rare plant species since the late nineteenth century, and whether these spatial and temporal patterns of rare species occurrences differ according to their chorology (level of endemism and biogeographic affinity). Location An area extending over 6250 km² in the French Mediterranean Region. Methods We used two botanical surveys achieved in 1886 and in 2001, and considered species rare if occurring in only one or two sites in the study area. Each rare species was assigned to a group of endemism level (restricted endemic, non‐endemic), and of biogeographic affinity (Mediterranean, South/Central European, Mountain, Eurosiberian). A 1 × 1 km grid was applied to the study zone. Generalized linear models were developed to study the spatial distribution and the fate of rare species occurrences (local extinction vs. local persistence between 1886 and 2001), as a function of environmental and human variables. Multivariate analyses were used to test whether the spatial distribution and the fate of rare species occurrences differed according to their chorology. Results In 2001, rare species as a whole tended to occur at higher altitude, in zones dominated by semi‐natural open habitats, and where cultivated area had decreased in the last 30 years. Between 1886 and 2001, rare species were the most prone to local extinction in zones where human population density, cultivated area and livestock density had increased the most. Between 1886 and 2001, rare species had a higher probability of local persistence in zones of high altitude and steep slope, on basic bedrocks and with low cultivated area. Rare species with Mountain and Eurosiberian affinities occurred in marginal habitats in the study region, i.e. on gneiss‐micaschist bedrocks and at high altitudes, whereas Mediterranean and South/Central European rare species occupied more varied environmental conditions. Between 1886 and 2001, Eurosiberian rare species showed high rates of local extinction whereas Mediterranean rare species had a significantly higher probability of local persistence. Restricted endemic species mostly occurred in zones of high slope, low human population density, and where cultivated area had decreased in the last 30 years. Occurrences of restricted endemics remained significantly stable between 1886 and 2001. Main conclusions Environmental and land‐use changes that occurred over the twentieth century in the Mediterranean Basin had significant impacts on the spatial distribution and on the long‐term dynamics of rare species occurrences. Urbanization and recent agriculture intensification, occurring mainly in coastal plains and littoral zones, caused most local extinctions of rare species from 1886 to 2001. Local populations of Eurosiberian species, which reach their range limits in marginal zones of the Mediterranean, also appear to be highly vulnerable. Conversely, most restricted endemic species occur in habitats with harsh topography and low human disturbance and have a higher potential of local persistence.     

Earthworm populations in conventional and integrated farming systems in the LIFE Project (SW England) in 1990–2000

Dilute formalin was used to sample earthworm populations in a field experiment comparing conventional (CFS) and integrated (IFS) farming systems, at Long Ashton in SW England during 1990–2000. Crops in the CFS were established by ploughing. Those in the IFS treatments were established by non‐inversion tillage: in the first 5 yrs using a Dutzi cultivator or by direct drilling (IFS‐1); from 1994 onwards using either a Vaderstad cultivator (IFS‐2) or a Dutzi cultivator (IFS‐3). These treatments had little or no effect on earthworm populations over the first 3 yrs of the experiment, but after this time total earthworm numbers and biomass were generally greater in the IFS treatments than in the CFS. Individual earthworm species (determined from 1995 onwards) differed in their response to the different farming systems. Numbers of Allolobophora chlorotica, Lumbricus festivus, L. rubellus and L. terrestris averaged over all years were significantly greater in IFS‐3 than in CFS, with densities in IFS‐2 nearly always intermediate and not significantly different from either extreme. Average treatment differences for other species were not significant, although in most years numbers of Aporrectodea longa, Lumbricus castaneus and Octolasion spp. were greatest in IFS‐3, with IFS‐2 similar to or less than CFS. There were no consistent differences between treatments for Aporrectodea caliginosa and A. rosea. Tillage method and the number of crop establishment passes were probably the main factors affecting earthworm populations, although the abundance and distribution of some species may also have been influenced by the amount of soil organic matter. During the period 1995–2000,13 species of earthworms were recorded from the site with A. caliginosa and Al. chlorotica the dominant species. These and other species which normally live in temporary burrows close to the soil surface formed about 80% of the total earthworms extracted, with the larger deep burrowing species, such as A. longa and L. terrestris, representing <20% of the total catch. Species diversity was consistently greater in the Dutzi‐based integrated system (IFS‐3) than in either the Vaderstad‐based integrated system (IFS‐2) or the conventional system (CFS). It is suggested that knowledge of the species composition of earthworm communities is essential in order to properly anticipate the likely impact of modified farming practices on earthworm populations. Careful consideration of the specific machine(s) used for tillage operations may also be required.     

Invasion Patterns of Lumbricidae Into the Previously Earthworm-free Areas of Northeastern Europe and the Western Great Lakes Region of North America

We examine the patterns of expansion of exotic European earthworms in northeastern Europe and the western Great Lakes region of North America. These areas share many ecological, climatic and historical characteristics and are devoid of indigenous earthworm fauna due to Quaternary glaciations. These regions are being colonized by a similar suite of exotic lumbricid species and it is unlikely that this is the result of chance, but rather indicates that these species have particular characteristics making them successful invaders. The present macro-scale distributions of earthworm species in northern Russia show little connection to the pattern of the last glaciation. Rather, the primary factors that determine the current distributions of earthworm species include climatic conditions, the life history traits of different earthworm species, the suitability of habitat and intensity and patterns of human activity. In the western Great Lakes region of North America, there are three primary factors affecting current distributions of exotic earthworm species including the patterns of human activity and land use practices, the composition of particular source populations of earthworms associated with different vectors of transport and the soil and litter properties of habitats across the region. Disturbance of a habitat does not appear to be a prerequisite to the invasion and establishment of exotic earthworms. Analysis of the macro-scale distributions of Lumbricidae species in northeastern Europe may provide important insights into the potential of invasive European earthworm species to spread in North America, and identify potentially invasive species.     

Spatial patterns of the Iberian and Balearic endemic vascular flora

The Iberian flora has a high degree of originality (1328 endemic species, 24% of endemism), comparable to other regions in the Mediterranean Basin. The richness of Iberian endemic species is unevenly distributed; the greatest diversity is found in the main mountain ranges although the southwestern Atlantic coast and specially the Balearic Islands are rich in range-restricted endemic species. The largest number of endemic genera is found in the northwestern mountains, which might have acted as a refugium area. The Baetic System, which includes nearly half (46%) of the total Iberian endemic species, is by far the richest region of the territory. Its endemic flora is characterized by the great richness of narrow endemics and the high species turnover rate. The k-means partitioning analysis enables us to identify 11 units, generally well defined by the natural geographic features. The clusters including the northwestern mountains, the Cantabrian Mountains, the southwestern coast and especially the Balearic Islands, the Pyrenees and the Baetic System are compact and consist of a high proportion of diagnostic species, and can therefore be considered areas of endemism on a large scale. The regionalization reflects a primary longitudinal division of Iberia between a basic eastern and an acidic western region, but also partly reveals a climatic division between Eurosiberian and Mediterranean regions. Southeastern Iberia seems to be an important center of differentiation for several typically Mediterranean genera (e.g. Centaurea, Linaria, Armeria, Teucrium and Thymus), but other large genera are also highly diversified.     

Eurosiberian meadows at their southern edge: patterns and phytogeography in the NW Tien Shan

Question: What are the community types, underlying gradients and phytogeographical affinities of montane meadows in the western Tien Shan? Location: Aksu‐Jabagly Nature Reserve, South Kazakhstan, Middle Asia. Methods: Species composition, structural and environmental variables were studied in 98 plots. Species composition was classified by cluster analysis and gradients explored using NMDS. Relationships between species richness, environmental and structural variables were investigated with regression analysis. Phytogeographic patterns were assessed by examining species distribution types. Results: Seven community types were distinguished by cluster analysis. Three axes of the NMDS explained 77% of the variation, showing different overlap of communities with environmental and structural properties. Species richness showed linear relationships with pH, altitude, heat load, soil skeletal content and structural variables. Middle Asian and Eurosiberian species constituted the majority of the species pool and cover. Conclusion: The studied communities represent a unique mixture of Middle Asian and Eurosiberian species that exhibit structural and environmental similarities to Eurosiberian meadows. The Tien Shan mountain meadows can thus be considered an endemic‐rich southern outlier of the broader Eurosiberian meadow formation. Shifts in land‐use patterns pose a potential threat that deserves more attention from conservationists.     

Synopsis of the rupicolous vegetation of Galicia (North-western Iberian Peninsula)

In this paper we present a synopsis of the rupicolous vegetation found in Galicia, according to the Zürich-Montpellier School. The climate of this territory, an area of 29,439 km² situated in the Northwest of the Iberian Peninsula, is largely Atlantic European becoming subhumid Mediterranean with a Central European tendency in the east of the region. There is an appreciable summer drought but annual rainfall is high: ombroclime is thus hyperhumid or humid becoming subhumid in the Southeast. Biogeographically most of the area is Eurosiberian except part of the Southeast, which is Mediterranean. Acidic rocks (granites, gneissic, schists and slates) predominate; there are also smaller areas of limestone, gabbros, and metabasic and ultrabasic rocks, some of this last type are serpentine. In this synthesis, we report 17 associations and 16 subassociations as well as 3 communities of unknown syntaxonomy. Of these, 1 association and 9 subassociations are described as new syntaxa and the names of 3 associations are corrected. The principal ecological conditions that influence the composition and distribution of these associations and its biogeographic and bioclimatic characteristics are presented in two summarizing tables. Floristic differences between the associations included in this synopsis are summarized in a synoptic table.     

Seasonality of spiders (Araneae) in Mediterranean ecosystems and its implications in the optimum sampling period

Abstract.  1. Fields such as ecology, macroecology, and conservation biology rely on accurate and comparable data. This is especially important for mostly unknown and megadiverse taxa such as spiders and regions such as the Mediterranean. Short-term sampling programmes are increasingly seen as the best option for sampling spiders. Comparability of results, however, demands standard procedures both in methodology and in sampling period. Cost-efficiency dictates that this period should be the most species rich.
2. Pitfall trapping was conducted in 23 sites from north to south Portugal, comprising three large-scale environmental zones and many different habitat types, during 10 months in each site. The annual richness pattern, differences in this pattern between areas and habitats, the complementarity between sampling periods and possible environmental correlates of richness were studied.
3. May and June present the optimal time for collecting spiders in Mediterranean areas. Northern areas have a later peak in richness and dense tree-cover sites offer more flexibility for sampling, with a higher proportion of species present at each period throughout the year.
4. Day length is the environmental factor most correlated with species richness. Maximum daily temperature may reduce richness, especially in southernmost areas, where summer temperatures can be extremely harsh.
5. It is recommended that short-term sampling programmes, intended to give a reasonable picture of spider communities in Portugal and in the Iberian Peninsula (and possibly extending to all the Mediterranean), should be conducted during May or June, with variable flexibility according to area and habitat. The proposed suggestions should appeal to everyone working in the field, given the cost-efficiency and comparability of results by adopting a common standardised approach.     

Non-native earthworms in riparian soils increase nitrogen flux into adjacent aquatic ecosystems

Riparian zones are an important transition between terrestrial and aquatic ecosystems, and they function in nutrient cycling and removal. Non-native earthworms invading earthworm-free areas of North America can affect nutrient cycling in upland soils and have the potential to affect it in riparian soils. We examined how the presence of earthworms can affect riparian nutrient cycling and nutrient delivery to streams. Two mesocosm experiments were conducted to determine how (1) the biomass of earthworms and (2) earthworm species can affect nutrient flux from riparian zones to nearby streams and how this flux can affect streamwater nutrients and periphyton growth. In separate experiments, riparian soil cores were amended with one of four mixed earthworm biomasses (0, 4, 10, or 23 g m(-2) ash-free dry mass) or with one of three earthworm species (Aporrectodea caliginosa, Lumbricus terrestris, L. rubellus) or no earthworm species. Riparian soil cores were coupled to artificial streams, and over a 36-day period, we measured nutrient leaching rates, in-stream nutrient concentrations, and periphyton growth. Ammonium leaching increased with increasing biomass and was greatest from the A. caliginosa treatments. Nitrate leaching increased through time and increased at a greater rate with higher biomass and from cores containing A. caliginosa. We suggest that the overall response of increased nitrate leaching [90% of total nitrogen (N)] was due to a combination of ammonium excretion and burrowing by earthworms, which increased nitrification rates. During both experiments, periphyton biomass increased through time but did not differ across treatments despite high in-stream inorganic N. Through time, in-stream phosphorus (P) concentration declined to <5 microg l(-1), and periphyton growth was likely P-limited. We conclude that activities of non-native earthworms (particularly A. caliginosa) can alter biogeochemical cycling in riparian zones, potentially reducing the N-buffering capacity of riparian zones and altering stoichiometric relationships in adjacent aquatic ecosystems.     

STUDIES ON THE RELATIONSHIPS BETWEEN EARTHWORMS AND SOIL FERTILITY: I. BIOLOGICAL STUDIES IN THE FIELD

Changes in the seasonal activity of several species of earthworms have been followed in a permanent pasture field for 18 months, 1945–6. The two soil conditions which chiefly determine activity are temperature and moisture. Other factors are the occurrence of an obligatory diapause in the two species Allolobophora nocturna and A. longa , and changes in population in A. chlorotica and Lumbricus terrestris.
Soil temperature and soil moisture also determined the weight of soil thrown up in the form of wormcasts during autumn, winter and spring. It is suggested that only two species, A. nocturna and A. longa , are responsible for wormcasts and that the other four common species present play little or no part in this activity.
At Rothamsted it was found that the previous agricultural history of the field is an important factor in determining the fauna. Old permanent pasture is characterized by a high percentage of A. nocturna and a rather lower percentage of A. caliginosa. Ploughing old permanent pasture and reseeding to grass after 1 or 2 years arable reduces the proportions of A. nocturna and A. caliginosa and increases that of Eisenia rosea. Arable fields have A. chlorotica as the dominant species and pasture fields 2–7 years grass after many years of arable fanning still show a high percentage of A. chlorotica and a low proportion of A. nocturna.
A survey of the Carse of Stirling, Scotland, showed that soil type is also an important factor in determining the earthworm fauna. A. caliginosa was the dominant species on the three soil types studied, but the subdominant species varied. On clay soil, A. longa was subdominant; on loam, A. longa and L. rubellus ; on sandy soil, A. longa, L. rubellus and A. chlorotica. The dominant species of pasture land at Rothamsted, A. nocturna , was not found at Stirling.