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Abstract

This study explores the factors affecting the biodiversity of diatoms, vegetation with focus on bryophytes, and invertebrates with focus on water mites, in a series of 16 spring-habitats. The springs are located primarily from the mountainous part of the Emilia-Romagna Region (Northern Apennines, Italy), and two pool-springs from agricultural and industrial lowland locations. Overall, data indicate that biological diversity (Shannon-Wiener, α-diversity) within individual springs was relatively low, e.g.: Sdiatoms = 0–46, Swater-mites = 0–11. However, when examined at the regional scale, they hosted a very high total number of taxa (γ-diversity; Sdiatoms = 285, Swater-mites = 40), including several new or putatively-new species, and many Red-List taxa. This pattern suggested there is high species turnover among springs, as well as high distinctiveness of individual spring systems. A key goal was to assess the hydrogeological and hydrochemical conditions associated with this high regional-pool species richness, and to provide a guide to future conservation strategies. There was a striking variety of geological conditions (geodiversity, captured mainly with lithotype and aquifer structure) across the study region, which led to wide variation in the hydrosphere, especially in conductivity and pH. Agriculture and industrial activities (anthroposphere) in the lowlands resulted in nutrient enrichment and other forms of pollution. Across all 16 spring-systems, several hydrogeological conditions most strongly influenced the presence or absence of particular biota and were determinants of species importance: spring-head morphology, hydroperiod, discharge, current velocity, and elemental concentration. These findings have important practical consequences for conservation strategies. Our data show that it is imperative to protect entire regional groups of springs, including representatives of the different ecomorphological spring types, lithologies, and degrees of human influence. These findings suggest that springs, when studied from an ecohydrogeological perspective, are excellent systems in which to further investigate and understand geo-biodiversity relationships.
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... Moreover, some of the studies that identified nitrate as an important correlate of RL indices did not include TP measurements [97], which may be autocorrelated with nitrate. Nevertheless, there is empirical evidence that elevated nitrate levels caused by direct loadings are not always concomitant with an increase of TP in springs [55]. Overall, our findings confirm the hypothesized negative correlation between the RL share and the trophic state, while the number of RL taxa and abundance were not correlated. ...
... An unexpected observation was the positive correlation of magnesium (Mg) with RL richness across all assemblages ( Figure S1). Mg is known to influence diatom community composition, e.g., in springs from the Apennines [55] or in petrifying springs from Lower Belgium [98]. Moreover, some diatoms are closely bound to alkaline conditions with high Mg contents, such as Achnanthidium dolomiticum Cantonati & Lange-Bertalot [54,76]. ...
... This probably explains the higher number of RL taxa in the western region, which is rich in lakes on dolomite bedrock. Previous studies have found a correlation between geodiversity and biodiversity of springs [55] and streams [99]. In our dataset, RL richness was positively correlated with total diatom richness, suggesting a possible indirect effect of geodiversity on RL diatom richness. ...
Article
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Mountain lakes are unique and often isolated freshwater habitats that harbour a rich biotic diversity. This high conservation value may be reflected by diatoms, a group of algae that is known for its reliability as a bioindicator, but which has not been studied extensively in mountain lakes of the northern European Alps. In this study, the conservation value of these lakes was assessed by characterizing the number, share, and abundance of diatom Red List (RL) taxa and their relationship with environmental variables, diatom α and β diversity (assemblage uniqueness). For this purpose, linear regression models, generalized linear models, and generalized additive models were fitted and spatial descriptors were included when relevant. Of the 560 diatom taxa identified, 64% were on the RL and half of these were assigned a threat status. As hypothesized, a decreasing share of RL species in sediment and littoral samples at higher trophic levels was reflected by higher total phosphorous content and lower Secchi depth, respectively. Species-rich lakes contained a high number of RL taxa, contrasting our hypothesis of a logarithmic relationship. In turn, RL abundance increased with uniqueness, confirming our initial hypothesis. However, some of the most unique sites were degraded by fish stocking and contained low abundances of RL species. The results demonstrate the importance of oligotrophic mountain lakes as habitats for rare freshwater biota and their vulnerability in light of human impact through cattle herding, tourism, damming, and fish stocking. Additional conservation efforts are urgently needed for mountain lakes that are still underrepresented within legal conservation frameworks. Species richness and uniqueness reflect complementary aspects of RL status and thus should be applied jointly. Uniqueness can indicate both pristine and degraded habitats, so that including information on human impacts facilitates its interpretation.
... In addition, chemical conditions can be altered by agricultural and industrial activities, especially in the lowlands, resulting in nutrient enrichment and other forms of pollution. High geological diversity translates into high spring ecomorphological and hydrochemical diversity, which in turn, is reflected in high g-biodiversity (Cantonati et al., 2020a). An applied consequence of the highly individualistic nature of springs, is that it is imperative to protect entire regional groups of springs, including representatives of the different ecomorphological spring types, lithologies, and degrees of human influence (Cantonati et al., 2020a). ...
... High geological diversity translates into high spring ecomorphological and hydrochemical diversity, which in turn, is reflected in high g-biodiversity (Cantonati et al., 2020a). An applied consequence of the highly individualistic nature of springs, is that it is imperative to protect entire regional groups of springs, including representatives of the different ecomorphological spring types, lithologies, and degrees of human influence (Cantonati et al., 2020a). Springs also host many sensitive, rare, threatened, Red List relict, and exclusive species. ...
... circulare). The importance of lithology-related abiotic parameters (conductivity, pH) has been confirmed many times (e.g., Cantonati et al., 2012bCantonati et al., , 2020a. Werum and Lange-Bertalot (2004) showed that spring diatom communities in a lithologically heterogeneous region can be assigned to different geological formations on a statistically significant basis. ...
Chapter
This chapter briefly reviews the theoretical frameworks provided for springs across disciplines and scales (habitats, ecosystems, multiple ecotones, etc.), and their unique properties and features (extreme heterogeneity, biodiversity hotspots, refugia, least-impaired habitat relicts, etc.). Special attention is devoted to a synthesis of the main classification approaches to springs, and to a succinct representation of the main kinds of springs. The chapter also offers an overview of the main groups of photoautotrops in springs, discussing their diversity, main characteristics, and environmental determinants. Finally, the highly endangered condition of spring habitats worldwide (silent global crisis of spring demise) is acknowledged, discussing threats, and potential resilience, remediation, and restoration strategies.
... So far, applications of the diatom Red Lists for Germany (Lange-Bertalot 1996;Hofmann et al. 2018) have been relatively rare but included a fair variety of inland-waters' habitats: springs (e.g., Werum and Lange-Bertalot 2004;Cantonati et al. 2012), mountain mires (e.g., Fránková et al. 2009;), glacial streams (e.g., Fell et al. 2018, alpine aquatic habitats (e.g., Falasco and Bona 2011), high-mountain lakes (e.g., Tolotti 2001, including paleolimnology: Cantonati et al. 2021, large peri-alpine lakes (Spitale et al. 2011), Mediterranean streams (e.g., Falasco et al. 2016Cantonati et al. 2020c). ...
... Six other species are suspected of being neobiota due to their distribution and spreading: Achnanthidium druartii, Capartogramma crucicula, Encyonema triangulum, Gomphoneis minuta, G. transsilvanica, and Gomphosphenia oahuensis. Achnanthidium, known to include many pioneer species (Rimet and Bouchez 2012;Cantonati et al. 2020c), is the genus with the majority of species amongst the ten taxa discussed as potential neophytes. However, Hofmann et al. (2018) prefer not to classify any of these species as neophytes for the time being, since it cannot be ascertained that their spread resulted from human intervention. ...
... On a similar note, Denys (2000) pointed out the relevance of developing specific lists for regions in which naturally-eutrophic waters are particularly common. Cantonati et al. (2020c), during a tentative application of a Red-List approach to streams in the water-stressed island of Cyprus, found, somewhat unexpectedly, that both species from threat categories of RL18 and putative threat-category species of a possible future Red List tailored for Cyprus occurred more frequently and were more relevant in assemblages from sites in intermittent streams. Since temporary streams are more characteristic than permanent ones in the Mediterranean climatic setting, this points to the necessity of developing diatom red lists tailored for the different biogeographic and climatic ecoregions. ...
Article
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Freshwater biodiversity is disproportionally endangered and under-prioritized. Algal Red Lists literature is very limited, and there are only two editions of a single diatom-specific Red List (developed for Germany), in spite of the importance of diatoms for biodiversity and global ecosystem functioning. We used and analysed the new diatom Red List, compared to the previous edition, to show that these diatom microalgae threat status data allow, on one hand, a characterization of the ecological integrity and of the diatom diversity of the different types of inland-water ecosystems (also of practical importance to designate the most relevant habitats for conservation purposes), including a clear assessment of the threat status of the habitat, and, on the other hand, they offer ample possibilities to track the effects of stressors and of environmental change. Our results revealed, among other things, that: (1) threatened taxa concentrate in dystrophic-oligotrophic environments; (2) ‘not threatened’, i.e. tolerant and opportunistic, taxa are most frequent in eutrophic and saline ecosystems; (3) most local diatom extinctions happened in carbonate oligotrophic habitats. In this study, nitrates could be shown to possess a highly significant negative association with the cumulative percentage of diatom taxa in threat categories of the Red List. Having included heterogeneous studies (diverse inland-waters, different geographic areas, from close-to-pristine to impacted, neo- and paleolimnology etc.), we think that this strong negative association is noteworthy and points to the high potential of diatom-Red-List based approaches, especially if these would be tailored for the different biogeographic and climatic ecoregions.
... Despite its low number of species and the fact that it is not an abundant and widely studied genus, species of Gomphosphenia have been found all over the world, some of them over the last 15 years: G. patrickiana Kociolek et al. 2014: 45, figs 65: 1-6) in the United States, G. biwaensis Ohtsuka & Nakai (in Ohtsuka et al. 2018, figs 4-22, 27-30) in Japan, G. pfannkuchae Cholnoky (in Lange-Bertalot 1995: 244) in southwest Africa, G. fontinalis Lange-Bertalot, Ector & Werum (in Werum & Lange-Bertalot 2004: 163, figs 94: 1-16) in Germany and G. plenkoviciae Gligora-Udovič & Zutinić (in Udovič et al. 2018: 231, figs 2-42) in Croatia. Moreover, Gomphosphenia species have been found in diverse types of habitats, such as streams (Falasco et al. 2018), lakes (Ohtsuka et al. 2018) and springs (Cantonati et al. 2020). This genus has been mainly found in alkaline and oligotrophic waters (Genkal & Yarushina 2016, Oliveira & Bicudo 2018. ...
Article
Gomphosphenia minima sp. nov. is a new freshwater diatom described from central Portugal, found in samples from a mountain stream. The species is described here based on light and scanning electron microscopy. This taxon is compared with other Gomphosphenia taxa such as G. fontinalis, G. lingulatiformis and G. tackei. Gomphosphenia minima sp. nov. is characterized by clavate to linear-lanceolate valves with rounded apices and a wide axial area not clearly separated from the central area. This taxon can be confused with G. fontinalis in terms of length and the shape of the central and axial area but they can be easily differentiated because the new species is narrower and the stria density is lower. The new species was found in low abundance in February 2012 and the stream had low electric conductivity levels, neutral pH values, low water temperature and low nutrient content.
... The high beta diversity was also reflected in the high gamma diversity in the spring habitat as a whole. The same trend of low alpha but very high gamma diversity was also observed in spring habitats of the Northern Apennines (Cantonati et al., 2020). The observed and estimated beta diversity values were significantly higher in the springs than in the rhithral streams. ...
Article
1. Springs are perceived by human society as essential sources of drinking water, but on the other hand they represent peculiar and vulnerable ecosystems. They differ from other watercourses in the relatively high stability of their physicochemical conditions. As a result, springs represent ecosystems with an insular character, usually inhabited by specific aquatic communities. 2. Although springs are generally considered species-rich habitats across the world, they have been outside scientific and conservation interest in the karst mountains of the Western Carpathians. This study, therefore, examined the diversity of spring benthic macroinvertebrates and compared it with that of other watercourses of the Western Carpathian riverine landscape. 3. The results of the study showed that, in contrast to rhithral streams, individual karst springs often had low species richness, and therefore they cannot be considered biodiversity hotspots. However, their metacommunity diversity is characterized by high taxonomic turnover, resulting in high gamma diversity. This means that the individual springs often harbour unique macroinvertebrate communities, so they are worthy of protection. 4. However, the present level of spring habitat protection is insufficient as even springs located in protected areas are often captured as sources of drinking water and hydromorphologically or otherwise disturbed. A simple method to evaluate the spring conservation priority (CP) was developed to find a better trade-off between their use and protection. It uses the number of Red List, endemic and crenal taxa, as well as the total species richness at each site. Based on this classification method, 16% of the springs studied reached very high CP, 39% high CP, 33% moderate CP and 12% low CP. 5. The proposed management recommendations based on findings of conservation priority of the Western Carpathian karst springs can significantly contribute to their more effective protection and the creation of a legislative framework relating to spring habitat protection in general.
... Many of the springs are colonized by diverse diatom communities influenced by differences in geology, water chemistry, microhabitat types, altitude etc. (Gerecke et al. 2007). They can be considered a link between aquatic and terrestrial habitats (Cantonati et al. 2020a) and in many cases are inhabited by taxa typical for subaerial habitats (Lowe et al. 2017) and streams (Czerwik-Marcinkowska et al. 2018). Despite their small size, springs provide refugia for many rare and endangered species (Cantonati et al. 2012b, Hofmann et al. 2018. ...
Article
The Krka River is located at Balkan Peninsula in the Dinaric region of Croatia and it is a typical groundwater-fed karst river characterized by an unusual phenomenon-tufa. Tufa designates porous CaCO3 deposits forming under specific physical and chemical conditions and hosting very diverse freshwater biota. Karst springs are considered one of the most diverse habitats for diatoms and are usually inhabited by specific diatom assemblages, which include the Krka spring zone. However, such habitats are particularly impacted by human activities, so previous studies have recently been conducted to raise awareness of the importance of karstic spring zones, especially because they are inhabited by specific and rare species. During the research at Krka River, samples were collected in the spring zone in May 2017, and the observations revealed the existence of a one Cymbopleura species characterized by slightly convex to almost linear valves, which are slightly protracted, broadly rounded and weakly dorsally bent at the apices. Based on detailed morphological analyses on light and scanning electron microscopy it appears that this population resembles two previously described taxa: C. rupicola var. minor Krammer and C. rupicola var. korana Krammer. Here we provide a more detailed description of the mentioned population under the new name Cymbopleura amicula stat. nov. et nom. nov. due to the significant differences from C. rupicola, together with a comparison with similar taxa in Cymbopleura.
... In spring habitats, Taxböck et al. [47] found that discharge was an important variable influencing diatom specie richness along elevational gradients and that higher flow rates tended to lead to higher similarities among diatom communities developing on different substrata (= in different microhabitats within a spring). Cantonati et al. [48] noted that the relevance of discharge variability sometimes tends to be underestimated in spring investigations because permanent, stable springs are often selected for this type of study. ...
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We studied diatoms from the fifteen springs selected in the Berchtesgaden National Park on be-half of the Bavarian State Ministry for the Environment to be sentinel environments of cli-mate-change effects. For three of these springs, diatom data based on samples taken in 1997 were also available. A total of 162 species belonging to 49 genera were found sampling three micro-habitat types (lithic materials, bryophytes, surface sediments). The cumulative percentage of all species included in a threat category including endangered species was 43%, confirming previ-ous findings for comparable environments of the Alps. We could find a statistically significant positive association between the Meinzer variability index for discharge and the cumulative rel-ative abundance of aerial diatom species. This study thus highlighted once again the relevance of discharge (and associated water-level) variability as an environmental determinant of diatom assemblages in spring ecosystems. Increased nitrate concentrations in some springs, likely due to diffuse airborne pollution and, locally, to impacts such as forest management, game, and cat-tle, led to a relevant occurrence of eutraphentic diatom species. Our results show a segregation of the older data in non-parametric diatom-based ordinations, suggesting a strong potential for the use of spring diatoms in studies aiming at tracking the effects of climate and environmental change.
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Springs represent relevant habitats which support high levels of biodiversity and productivity, providing refugia to both plants and animals together with essential ecosystem services. However, springs are often overlooked or even destroyed by human activity. Locating, inventorying, and monitoring springs is, therefore, becoming of increasing importance. This study aims at developing a multidisciplinary approach to detect ephemeral springs, which can only be discovered by hydrogeological surveys when discharge occurs. We suggest potential cooperation between hydrogeologists and botanists based on the use of a plant species as an indicator of the occurrence of ephemeral springs fed by ophiolitic perched groundwater aquifers. In this study, the grass Molinia arundinacea was used as a bioindicator, observed in periods when there was no discharge and whose occurrence on ophiolite bodies was revealed by previous studies in the northern Apennines (Italy). A total of twenty ophiolitic bodies were explored and grassland stands including Molinia populations were discovered in 86 springs (15 reported for the first time). Detailed geomorphological and hydrogeological sampling was also performed in ten springs, recording the occupancy area, cover and functional traits of Molinia at two permanent and eight ephemeral springs and along their streambeds. Molinia not only colonised the spring outlets, but also occurred along the streambeds fed by ephemeral springs, with a higher occupancy area where the rocky outcrops were covered by detrital deposits and at the base of the morphological incision. Additionally, the cover of Molina populations was correlated with the average water discharge, with the highest functional trait values found in locations with high soil moisture. Results confirmed that while Molinia performs best on permanently moist soils, it is also able to grow on soils with a fluctuating water-table or even in dry conditions, thus representing an excellent indicator of springs fed by temporary perched aquifers.
Preprint
Despite the ecological significance of desert springs, little is known about relationships between spring hydrogeochemistry and ecology, particularly over multiple trophic levels. Here, we surveyed microbial communities (bacteria and archaea) and benthic macroinvertebrate (BMI) communities in springs that recharge through granitoid rocks in Owens Valley, CA, to determine whether subtle geochemical differences imparted by Paleozoic roof pendant weathering in the source area affects spring ecosystems. Relative to other springs, roof pendant-recharged springs were characterized by elevated: (i) Ca ²⁺ /Na ⁺ , Ca ²⁺ /Mg ²⁺ , and divalent/monovalent cation ratios, (ii) relative abundance of benthic aerobes/facultative anaerobes and holdfast/stalked bacteria, and (iii) abundance and diversity of shredder and collector-gatherer BMIs. These BMI feeding groups graze on biofilm communities and stimulate bacterial degradation of particulate organic matter, consistent with extensive bacteria-BMI connections in co-occurrence networks of these springs. Springs not impacted by roof pendants were instead enriched with anaerobes and chemolithotrophs and low-diversity BMI communities with poor bacteria-BMI network connectivity. We speculate that excess Ca ²⁺ derived from roof pendant weathering plays a key role in biofilm formation on coarse granite substrates, with subsequent synergy between benthic microbial biofilms and diverse BMI shredders/collector-gatherers to degrade allochthonous organic material.
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Aim Alpine spring ecosystems have long been considered as highly isolated, island-like habitats. This presumption, however, is insufficiently supported empirically and conclusions about spring isolation have been based on indirect evidence. Therefore, we investigated the population genomic structure of Partnunia steinmanni Walter, 1906, a strictly spring-dwelling water mite (Hydrachnidia) species, to shed light on the degree of interconnection among freshwater spring habitats. Location Protected areas across the Alps, Central Europe. Methods Partnunia steinmanni populations were sampled by hand-net from 12 springs. Population genomic structure was inferred with 2263 polymorphic restriction site-associated DNA (RADseq) loci of 256 individuals. We assessed genomic admixture, the phylogenetic relationship, isolation by distance, contemporary migration, effective population sizes, and genetic diversity among individuals from different springs. Results We observed strong genetic differentiation between individuals from different springs. Water mites from each spring qualified as well-delimited distinct populations with only little intra-spring migration, even when these were located in close geographic proximity. Furthermore, we found subtle shared genetic structure among springs within the same area, and a southwestern genotype associated with the Rhône catchment that extended into eastern populations. Effective population size estimates and standing genetic variation within springs were generally low. Main conclusions Our findings indicate strong insularity of freshwater springs and headwater areas, likely caused by intra-alpine Pleistocene isolation and limited dispersal abilities of strictly spring-bound species like P. steinmanni. Our results support the concept of spring habitat isolation and highlight the importance of alpine protected areas to conserve springs as substantial components of freshwater biodiversity.
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First data on the biological richness of Mediterranean springs The taxonomic richness of the main biological groups in springs in the Mediterranean biogeographical region has been investigated for the first time. This work has focused on two mountainous areas of mainly limestone substrata: the Montsant massif (south of the Catalan pre-coastal ranges, NE Iberian Peninsula) and the Serra de Tramuntana (north of the island of Mallorca). The taxa of macroalgae, diatoms, bryophytes, cormophytes, aquatic invertebrates and vertebrates have been analysed in ten springs of each area, and a total of 500 taxa have been identified in Montsant (ranging between 82-152 taxa per site) and 363 taxa in Serra de Tramuntana (ranging between 55-119 taxa per site). Depending on each spring, the biological groups showing the greatest richness value are either cormophytes, diatoms or invertebrates. The resulting biological richness, which is reported for the first time in Mediterranean crenic systems, is similar to the values found in other published works on springs in the Euro-Siberian biogeographic region, showing their role as outstanding biodiversity hot spots also in Mediterranean environments. The similarity analysis showed that the springs shared a low number of taxa, resulting in a low value of similarity. In conclusion, the results suggested that each spring could represent a unique, unrepeatable community. RESUMEN Primeros datos sobre la riqueza biológica de las fuentes mediterráneas Se investiga por primera vez la estructura biocenótica y la riqueza taxonómica asociada a los hábitats fontanales de la región biogeográfica mediterránea, tanto en ecosistemas continentales como insulares, a través del inventariado de sus principales grupos biológicos. El trabajo se ha centrado en dos áreas montañosas de naturaleza calcárea: el macizo de Montsant (sur de las sierras prelitorales catalanas) y la Serra de Tramuntana (norte de la isla de Mallorca). Se ha analizado sistemáticamente los taxones de macroalgas, diatomeas, briófitos, cormófitos, invertebrados acuáticos y vertebrados en 10 fuentes de cada región, y se ha identificado un total de 500 taxones en Montsant (con un rango de 82-152 taxones por fuente) y de 363 taxones en la Serra de Tramuntana (con un rango de 55-119 taxones por fuente). Dependiendo de cada fuente, los grupos biológicos que exhiben mayor riqueza son los cormófitos, las diatomeas o los invertebrados. La riqueza biológica hallada y que reporta-mos por primera vez para ecosistemas fontanales mediterráneos, es similar a la encontrada por otros autores en fuentes de la región biogeográfica eurosiberiana y demuestra su papel como focos excepcionales de biodiversidad también en ambientes mediterráneos. El análisis de similitud muestra que las fuentes presentan una baja proporción de taxones coincidentes entre ellas, lo que resulta en un valor bajo de similitud. En consecuencia, los resultados sugieren que cada fuente podría conformar en sí misma una comunidad única e irrepetible.
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Context One approach to maintain the resilience of biotic communities is to protect the variability of abiotic characteristics of Earth’s surface, i.e. geodiversity. In terrestrial environments, the relationship between geodiversity and biodiversity is well recognized. In streams, the abiotic properties of upstream catchments influence stream communities, but the relationships between catchment geodiversity and aquatic biodiversity have not been previously tested. Objectives The aim was to compare the effects of local environmental and catchment variables on stream biodiversity. We specifically explored the usefulness of catchment geodiversity in explaining the species richness on stream macroinvertebrate, diatom and bacterial communities. Methods We used 3 geodiversity variables, 2 land use variables and 4 local habitat variables to examine species richness variation across 88 stream sites in western Finland. We used boosted regression trees to explore the effects of geodiversity and other variables on biodiversity. Results We detected a clear effect of catchment geodiversity on species richness, although the traditional local habitat and land use variables were the strongest predictors. Especially soil-type richness appeared as an important factor for species richness. While variables related to stream size were the most important for macroinvertebrate richness and partly for bacterial richness, the importance of water chemistry and land use for diatom richness was notable. Conclusions In addition to traditional environmental variables, geodiversity may affect species richness variation in streams, for example through changes in water chemistry. Geodiversity information could be used as a proxy for predicting stream species richness and offers a supplementary tool for conservation efforts.
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Background and aims – The detailed analysis of algae and cyanoprokaryotes in a heterogeneous group of spring habitats (including all the different typologies) of the northern Apennines (Emilia-Romagna Region, Italy) revealed a new Amphora species in a small mountain flowing spring with low conductivity, and a new Halamphora species in a large, inland-saline (Triassic gypsum), fast flowing spring (Poiano spring). The present study aims to describe in detail these two new species found in contrasting spring types. Methods – This study is based on light microscopy (both fresh –for plastids – and prepared materials) and scanning electron microscopy observations, as well as a thorough morphological, physical, chemical, and biological characterization of the habitats. Key results – Amphora eileencoxiae sp. nov. is most similar to A. vetula (and allied taxa), and is characterized by the outline with acutely rounded, moderately ventrally bent ends, by the dimensions, and by the well-defined, semi-elliptic dorsal area. Halamphora poianensis sp. nov. is most similar to H. gasseae but differs by the higher stria density, the clearly ventrally bent ends, and the strongly developed dorsal raphe ledge. Conclusions – This is a contribution to the knowledge of the genera Amphora and Halamphora in mountain springs in understudied geographic areas and inland-saline springs, the species communities of which are likely insufficiently explored.
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Spring water chemistry is influenced by many factors, including geology, climate, vegetation and land use, which determine groundwater residence times and water–rock interaction. Changes in water chemistry can have a profound impact on their associated ecosystems. To protect these ecosystems and to evaluate possible changes, knowledge of the underlying processes and dynamics is important. We collected water samples at 20 locations during 5 campaigns within the water catchment area of the upper Schönmünz river in the Black Forest National Park, Southwest Germany and analyzed them hydro-chemically for their contents of inorganic constituents, organic carbon content, fluorescence properties as well as several physico chemical field parameters and spring discharge. Results show that water chemistry is strongly dependent on geology and that the response of dissolved organic carbon to changes in hydraulic conditions is highly dynamic. Due to increased flow through the upper soil layer during and after rain events, more organic carbon is extracted from the soil and transported with the water. Fluorescence EEM measurements indicate an allochthonous source of this organic carbon. This study can be used as baseline to assess future changes and serve as a supplement to ongoing studies of the spring ecosystems.
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More or less needle-shaped species of Fragilaria s.s. are difficult to identify. Here we contribute to the taxonomy of this difficult group by describing three species new to science from very low conductivity mountain freshwater environments. two of the new species resemble taxa established by Kützing in the early 19 th century: F. rumpens and F. vaucheriae. Fragilaria spinaspeciosa sp. nov., from a seepage (helocrenic spring) in the northern apennines, is superficially similar to F. rumpens, but has a lower stria density. Fragilaria tridentina sp. nov. is distinguished from F. gracilis by its smaller length-to-breadth ratio and more closely spaced areolae. Fragilaria vaucheriaeraetica sp. nov. is distinguished from F. vaucheriae and F. microvaucheriae by its outline and denser striae. these last three species also have distinctly different ecologies. Fragilaria vaucheriaeraetica sp. nov. is found in very low conductivity, very low nitrate, ultra-oligotrophic waters, while F. vaucheriae and F. microvaucheriae are found in medium conductivity, high total phosphorus, and relatively high nitrate streams. accurate species identification and knowledge of each species' ecological preferences are critically important if diatoms are to be used effectively as indicators of environmental impact and climate change. Weakly buffered, low alkalinity, low nutrient and low conductivity mountain freshwater habitats are sensitive to human disturbance and biotopes for many rare (red List) diatoms. as such, they serve as valuable early warning systems for detecting the effects of climate change and other human activities.
Article
Following an update of the survey of the European water mite fauna (Acari: Hydrachnidia) last published by K. Viets (1978), we confirmed the occurrence of 970 species. Based on the evaluation of these data, new bibliography and our own unpublished data, the main habitat preference is determined for each species. The resulting ecological data are analysed with a main focus on species inhabiting groundwater-influenced habitats. No other invertebrate group includes a similarly high share of species with a particular relationship to spring habitats: about one fifth of the European Hydrachnidia has a preference for spring habitats, a total number of 137 (14%) is crenobiontic (living exclusively in springs). The following topics are addressed: (1) the significance of spring habitats for the diversity of water mites - percentage of crenobionts/crenophiles at different geographical latitudes; (2) regional stenotopy - intraspecific differences in habitat preference between populations at different latitudes; (3) communities colonizing springs vs. hyporheic - similarities and differences; (4) evolution of crenobiosis in water mites - potential governing factors; (5) endangered species - direct and indirect anthropogenic threats to the natural diversity of water mites.