Water mites as indicators of natural aquatic ecosystems of the coastal dunes of the Netherlands and northwestern France

A large number of coastal dune waters in the Netherlands and northwestern France have been investigated for the occurrence of water mites. Dune waters turned out to be very rich in water mite species. In the Dutch dunes, 110 species of water mites have been found; this is 50 % of the total number of water mite species present in the Netherlands. In the French dunes 64 species have been found. The water mites most characteristic of the coastal dunes are the temporary water species. Dune areas with a high-lying hinterland have a water mite composition much different from dune areas with a low-lying hinterland. This can be explained by the existence of a very different hydrology. During the last century human activity affected the ground water of dunes. Afforestation and extraction of ground water for drinking water purposes caused a lowering of the ground water table. As a result, many dune slacks dried out. Moreover, the infiltration of river water caused an eutrophication of the ground water. Nowadays, the dunes most rich in typical water mite species are the dunes in which neither infiltration of river water nor extraction for drinking water purposes, occur. It can be concluded that water mites are good indicators for dune areas with a natural hydrology.     

Vascular Plants Facilitated Bryophytes in a Grassland Experiment

In grassland communities vascular plants and bryophytes form two distinct layers. In order to understand the factors responsible for plant community structure, more information about interactions between these plant groups is needed. Often negative correlations between vascular plant and bryophyte covers have been reported, suggesting competition. Here we tested experimentally whether different grassland vascular plant species (Trifolium pratense, Festuca pratensis, Prunella vulgaris) had different influences on the cover of two bryophyte species (Rhytidiadelphus squarrosus, Brachythecium rutabulum). In a two-year garden pot experiment one bryophyte species and one vascular plant species were planted per pot. Bryophytes were planted at a constant density, vascular plants in four densities. The cover of both bryophyte species increased with increasing vascular plant cover, showing the facilitative effect of vascular plants through creating better microclimate, e.g., optimising temperature. Bryophyte responses to vascular plant species were species-specific. Festuca had significantly positive effects on both bryophyte species in the second year, and Trifolium on Brachythecium in both years, whereas Prunella had no significant effect on bryophytes. The facilitative effect of vascular plants was stronger at the second experimental year. In summary, the biotic effects between bryophytes and grassland vascular plants are species-specific and positive interactions are prevailing at low vascular plant densities.     

Community structure and diversity of bryophytes and vascular plants in abandoned fen meadows

We examined effects of abandonment on species diversity and species composition by comparing 21 calcareous fen meadows in the pre-alpine zone of central and northeastern Switzerland. Meadows were divided into three classes of successional stages (mown: annually mown in late summer, young fallow: 4–15 years, and old fallow: >15 years of abandonment). In each fen, we measured litter mass in four 20 cm×20 cm plots, as well as (aboveground) biomass and species density (number of species per unit area) of bryophytes and vascular plants. Bryophyte biomass was reduced in abandoned fens, whereas litter mass and aboveground biomass of vascular plants increased. Species density of both taxonomic groups was lower in abandoned than in mown fens. Young and old successional stages were not different except for bryophytes, for which old successional stages had higher species density than young stages. We used litter mass and aboveground biomass of vascular plants as covariables in analyses of variance to reveal their effects on species density of both taxonomic groups. For bryophytes, litter mass was more important than vascular plant biomass in explaining variance of species density. This indicates severe effects of burying by litter on bryophyte species density. For species density of vascular plants, both vascular plant biomass and litter mass were of similar importance in explaining the decreased species density. Canonical correspondence analyses showed that abandonment also had an effect on species composition of both bryophytes and vascular plants. However, young and old successional stages were not different indicating fast initial changes after abandonment, but slow secondary succession afterwards. Furthermore, indicator species analysis showed that there was no establishment of new species after abandonment that might dramatically alter fen communities. Re-introduction of mowing as a nature conservation strategy may thus be very promising – even for old fallows.     

Hydrological landscape settings of base‐rich fen mires and fen meadows: an overview

Question: Why do similar fen meadow communities occur in different landscapes? How does the hydrological system sustain base‐rich fen mires and fen meadows? Location: Interdunal wetlands and heathland pools in The Netherlands, percolation mires in Germany, Poland, and Siberia, and calcareous spring fens in the High Tatra, Slovakia. Methods: This review presents an overview of the hydrological conditions of fen mires and fen meadows that are highly valued in nature conservation due to their high biodiversity and the occurrence of many Red List species. Fen types covered in this review include: (1) small hydrological systems in young calcareous dune areas, and (2) small hydrological systems in decalcified old cover sand areas in The Netherlands; (3) large hydrological systems in river valleys in Central‐Europe and western‐Siberia, and (4) large hydrological systems of small calcareous spring fens with active precipitation of travertine in mountain areas of Slovakia. Results: Different landscape types can sustain similar nutrient poor and base‐rich habitats required by endangered fen meadow species. The hydrological systems of these landscapes are very different in size, but their ground water flow pattern is remarkably similar. Paleoecological research showed that travertine forming fen vegetation types persisted in German lowland percolation mires from 6000 to 3000 BP. Similar vegetation types can still be found in small mountain mires in the Slovak Republic. Small pools in such mires form a cascade of surface water bodies that stimulate travertine formation in various ways. Travertine deposition prevents acidification of the mire and sustains populations of basiphilous species that elsewhere in Europe are highly endangered. Conclusion: Very different hydrological landscape settings can maintain a regular flow of groundwater through the top soil generating similar base‐rich site conditions. This is why some fen species occur in very different landscape types, ranging from mineral interdunal wetlands to mountain mires.     

Impacts of alien plants and man‐made disturbance on soil‐growing bryophyte and lichen diversity in coastal areas of Sardinia (Italy)

Abstract

Seventy phytosociological relevés were performed in 1 m × 1 m plots at 14 study sites spread along sandy shores in northern and southern Sardinia (Italy). The plots were selected in different habitat types (open dunes, native Juniperus woodlands, maquis, and plantations with Acacia, Eucalyptus and Pinus) according to a stratified sampling method in order to investigate impacts deriving from different levels of Carpobrotus spp. cover, dry litter from exotic trees, and other disturbance types. The quantile regression and logistic regression analyses revealed that the reduction in the amount of bryophyte and lichen cover on sand dunes of the study area is caused either by a high cover of Carpobrotus spp. mats or by a high cover of dry exotic litter in dense, unmanaged or poorly managed forest plantations. Additional detrimental effects are often driven by other kinds of man‐made disturbances. Forest management in the coastal areas of Sardinia should be gradually modified to take into account the conservation of bryophytes and lichens. Some of the biological indicators used are quite widespread in the Mediterranean coastal habitats or are exclusively associated with sand dunes; therefore, they can also be conveniently used as indicators of biological impacts in other countries or islands of the same biogeographical region.     

Loss of habitat specialists despite conservation management in fen remnants 1995–2006

Many ecosystems of high conservation value have been shaped by human impacts over centuries. Today, traditional management of semi-natural habitats is a common conservation measure in Europe. However, despite traditional management, habitat remnants may still loose specialist species due to surrounding land-use change or atmospheric nitrogen deposition. To detect trends in species density (2-m² plot scale) and habitat quality in calcareous fens in the pre-Alps of Switzerland, we surveyed 36 traditionally managed fens in 1995/97 and again in 2005/06 (five plots per fen). The fens occurred at three altitudinal levels (800–1000, 1000–1200, 1200–1400 m asl) and were either extensively grazed or mown once a year. Despite these traditional management regimes, species density of fen specialists and of all bryophytes decreased during this decade (vascular plant specialists: ?9.4%, bryophyte specialists: ?14.9%, all bryophytes: ?5.7%). Management had no effect on the number of Red-List species and habitat specialists of vascular plants per plot. However, bryophyte species density was more strongly reduced in grazed fens. Species density of vascular plant generalists increased between the two surveys (+8.2%) but not of bryophytes. Among vascular plants, Red-List species decreased from 1.01 to 0.78 species per plot. Furthermore, between the two surveys aboveground plant biomass, mean plant-community indicator values for nutrients and species density of nutrient indicators increased, whereas mean plant indicator values for soil moisture, light and peat, and species density for peat indicators, decreased. We attribute these changes and the loss of specialist species over the past decade mainly to land-use change in the surrounding area and to nutrient inputs. Thus, despite traditional management, calcareous fens in the pre-Alps suffer from ongoing habitat deterioration and endangered plant species remain threatened. For their long-term protection, we suggest to reduce nutrient inputs and, where necessary, to restore hydrology and adjust grazing management.     

The distribution, density and biomass of terrestrial reptiles in Dominica, West Indies

Fourteen species of reptiles have been recorded from the island of Dominica, Lesser Antilles. As part of a larger study of the ecology of Dominica's forests, the distribution, density and biomass of three widespread lizard species ( Anolis oculatus, Ameiva fuscata and Mabuya mabouya ) were estimated in all major vegetation types. No consistent differences between seasons occurred for any of the three species, and at no site was a definite breeding season detected. Densities, estimated mainly by plot counts, were highest in coastal woodlands where mean densities reached 2148 Anolis per hectare, 379 Ameiva per hectare, and 751 Mabuya per hectare. Densities in rain forest sites were often very low. Combined biomass for the three species also reached a maximum in coastal woodlands of 44.7 kg/ha. This value is amongst the highest recorded for terrestrial reptile assemblages, and suggests that Dominica's coastal woodlands are unusually favourable habitats for reptiles.
Previous studies of Caribbean lizards have suggested that either competition or predation from birds may influence lizard densities. The present study, however, found no such relationships, and it was concluded that lizard density was independent of bird density.     

华南海岸典型沙生植物根系构型特征

选择华南海岸典型沙地, 采用全挖法, 对4种典型沙生植物木麻黄(Casuarina equisetifolia)、厚藤(Ipomoea pes-caprae)、老鼠艻(Spinifex littoreus)和狗牙根(Cynodon dactylon)的根系构型进行了研究。结果表明: 1)狗牙根和老鼠艻的根系总体分支率显著高于木麻黄, 厚藤最小, 说明大部分草本植物在生长过程中通过增加根系分支率, 提高物质传输效率, 除木麻黄外, 其他3个物种枝系均平卧伸展, 易于受到沙埋生出不定根, 进一步提高其物质传输效率; 2) 4种沙生植物根系平均连接长度最大的为木麻黄, 平均连接长度为19.25 cm, 且相对其他3个物种传导根所占的比例最大, 说明木麻黄通过增加平均连接长度以减少根系内部对土壤资源的竞争, 并提高传导根的比例, 以增加资源传输效率; 3) 4种沙生植物根系构型均倾向于叉状分支, 其中草本植物的根系构型更为接近, 说明草本植物受到的资源胁迫相对较小, 有利于在海岸沙地恢复中快速定居; 与内陆地区沙生植物相比, 海岸沙生植物在土壤资源的获取及空间拓展方面表现出显著的差异, 反映出不同生境条件下物种对生境胁迫的适应策略。因此, 海岸沙地前缘植被恢复应以草本植物为主, 尤其是具有不定根的物种, 乔木则不适合。     

Architectural characteristics of roots in typical coastal psammophytes of South China

选择华南海岸典型沙地, 采用全挖法, 对4种典型沙生植物木麻黄(Casuarina equisetifolia)、厚藤(Ipomoea pes-caprae)、老鼠艻(Spinifex littoreus)和狗牙根(Cynodon dactylon)的根系构型进行了研究。结果表明: 1)狗牙根和老鼠艻的根系总体分支率显著高于木麻黄, 厚藤最小, 说明大部分草本植物在生长过程中通过增加根系分支率, 提高物质传输效率, 除木麻黄外, 其他3个物种枝系均平卧伸展, 易于受到沙埋生出不定根, 进一步提高其物质传输效率; 2) 4种沙生植物根系平均连接长度最大的为木麻黄, 平均连接长度为19.25 cm, 且相对其他3个物种传导根所占的比例最大, 说明木麻黄通过增加平均连接长度以减少根系内部对土壤资源的竞争, 并提高传导根的比例, 以增加资源传输效率; 3) 4种沙生植物根系构型均倾向于叉状分支, 其中草本植物的根系构型更为接近, 说明草本植物受到的资源胁迫相对较小, 有利于在海岸沙地恢复中快速定居; 与内陆地区沙生植物相比, 海岸沙生植物在土壤资源的获取及空间拓展方面表现出显著的差异, 反映出不同生境条件下物种对生境胁迫的适应策略。因此, 海岸沙地前缘植被恢复应以草本植物为主, 尤其是具有不定根的物种, 乔木则不适合。     

Bryophyte and vascular plant species richness in boreo-nemoral moist forests and mires

We compare species richness of bryophytes and vascular plants in Estonian moist forests and mires. The material was collected from two wetland nature reserves. Bryophyte and vascular plant species were recorded in 338 homogeneous stands of approximately 1 ha in nine forest and two mire types. Regional species pools for bryophytes and vascular plants were significantly correlated. The correlations between the species richnesses of bryophytes and vascular plants per stand were positive in all community types. The relative richnesses (local richness divided by the regional species pool size) were similar for bryophyte species and for vascular plant species. This shows that on larger scales, conservation of the communities rich in species of one taxonomic plant group, maintains also the species richness of the other. The minimum number of stands needed for the maintenance of the regional species pool of typical species for the every community type was calculated using the species richness accumulation curves. Less stands are needed to maintain the bryophyte species pools (300–5300 for bryophytes and 400–35 000 for vascular plants).     

Impact of the invasive moss Campylopus introflexus on carabid beetles (Coleoptera: Carabidae) and spiders (Araneae) in acidic coastal dunes at the southern Baltic Sea

Campylopus introflexus is an invasive moss in Europe and North America that is adapted to acidic and nutrient-poor sandy soils with sparse vegetation. In habitats like acidic coastal dunes (grey dunes) it can reach high densities, build dense carpets and modify habitat conditions. While the impact of the moss invasion on the vegetation is well analyzed, there is a lack of knowledge regarding possible effects on arthropods. In the present study we analyzed the impact of Campylopus introflexus on the ground-dwelling arthropods carabid beetles and spiders, as both taxa are known to be useful indicator taxa even on a small-scale level. In 2009 we compared species composition in a) invaded, moss-rich (C. introflexus) and b) native, lichen-rich (Cladonia spp.) acidic coastal dunes by using pitfall traps. A total of 1,846 carabid beetles (39 species) and 2,682 spiders (66 species) were caught. Species richness of both taxa and activity densities of spiders were lower in invaded sites. Species assemblages of carabids and spiders differed clearly between the two habitat types and single species were displaced by the moss encroachment. Phytophagous carabid beetles, web-building spiders and wolf spiders were more abundant in native, lichen-rich sites. Shifts in species composition can be explained by differences in the vegetation structure, microclimate conditions and most likely a reduced food supply in invaded sites. By forming dense carpets and covering large areas, the moss invasion strongly alters typical arthropod assemblages of endangered and protected (EU-directive) acidic coastal dunes.     

Ecological study of pine forest clearings along the French Atlantic sand dunes: Perspectives of restoration

The 18th century afforestation campaign carried out in western France to fix sand dunes has left only a small surface of non-forested dunes. As dune plantations have only a small conservation value, it would be of great interest to restore grey dunes. But, for the moment, there is no proof that pine felling would lead to grey dunes. So, a study has been carried out on pine forest clearings along the French Atlantic shoreline. Floral and ecological data were carried out and analysed with two statistical tools, CA (canonical analysis) and CCA (canonical correspondence analysis). The clearings appear very different from one bank of the Gironde river to the other. South of the river, the clearing vegetation develops on acid soils and possess some thermophilous species. North of the river, the clearings are composed mostly of species growing best on calcareous soils. Apart from geographical variations, clearings showed two patterns of response: development of closed thickets and tall heathlands; or an open vegetation similar to growing heathlands and grasslands. The cover, the height, the floral richness per strata as well as pedological characteristics are the parameters which explain the best floristic composition of pine clearings. The vigour of pine forests and the degree of exposure to coastal influences determine whether close or open vegetation develops. Where there is an open vegetation, restoration of grey dunes may be possible. In the other case, alternative solutions, such as the restoration of dune woodlands or dune heath, may provide best conservation values.     

Differential effects of ammonium and nitrate deposition on fen phanerogams and bryophytes

Question: High atmospheric nitrogen (N) deposition has been shown to affect productivity and species composition of terrestrial ecosystems. This study focused on the differential effects of the two inorganic N forms in atmospheric deposition (i.e. ammonium and nitrate). Methods and location: Nutrient addition experiments were carried out during 4 years in a mesotrophic fen in a low‐deposition area in Ireland. In a factorial design, plots were fertilized with ammonium and/or nitrate, in two doses comparable with 35 and 70 kg N ha^?1 y^?1 and compared with an unfertilized control. Results: Vascular plant biomass as well as bryophyte biomass were not affected by N dose but showed significantly different responses to the N form. In the ammonium‐fertilized plots, vascular plant biomass was higher and moss biomass was lower than the control, while nitrate additions had no effect. Vascular plant species density was high (16 species per 0.49 m²) and was not affected by any of the treatments; bryophyte species density was also high (seven species per 0.04 m²) but showed a significant decrease upon ammonium fertilization. Conclusion: The vulnerability of the mesotrophic vegetation to enhanced atmospheric N deposition depends strongly on the N form. If N would be mainly deposited as NO_x, no detrimental effects on the vegetation will occur. If, however, the deposition is mainly in the form of NH_y, the bryophyte vegetation will be seriously damaged, while the vascular plant vegetation will show an increased biomass production with possible shifts in dominance from Carex and herb species to grasses and shrubs.     

Are some communities of the coastal dune zonation more susceptible to alien plant invasion?

Aims Coastal areas, and in particular coastal dunes, are ecosystems strongly affected by the invasion of alien plants. However, few attempts have ever been made to quantify alien species incidence in different communities along the coastal zonation. This work aims to analyze the distribution of alien plants along the coastal zonation of sandy shores on the Tyrrhenian coast, addressing specifically differences among plant communities in abundance of alien plants.Methods The study was performed on recent dunes (Holocene) of the central western coast of Italy. We selected dune landscapes where invasion processes were particularly evident. Vegetation plots were randomly sampled and through cluster analysis, we identified six plant communities corresponding to the typical zonation described for the Tyrrhenian sandy coast of Central Italy. We evaluated and compared frequency and abundance of invasion in these different communities. Further, we investigated how propagule pressure (measured using as proxy human structures) contributed to the observed invasion patterns.Important findings We found a relatively low total number of aliens but also a differential distribution pattern and strong abundance of some of the aliens in specific sectors of the vegetation zonation. The perennial community of transition dunes appears most affected by invasion processes, related almost exclusively to the frequent and widespread Carpobrotus aff. acinaciformis. This alien species reaches high cover values, apparently lowering cover of native species of transition dune plant communities. Higher levels of invasion in the transition dune can be partially explained because of greater propagule pressure in this section of the dune profile. Our findings thus have important conservation and management implications since transition dune communities with Crucianella maritima are rare and protected (sensu Habitat 92/43/EEC Directive) along the entire Italian coast.     

Changes in forest understorey vegetation in Norway related to long‐term soil acidification and climatic change

Question: Does the understorey vegetation of Norwegian boreal forests change in relation to broad‐scale, long‐term changes? Location: Norway. Methods: Permanently marked 1‐m² vegetation plots from 17 monitoring reference areas in forests dominated by Picea abies (11 areas, 620 plots) and Betula spp. (six areas, 300 plots) were analysed twice, at the start in 1988–1997 and 5 yr later (1993–2002). Species subplot frequency data were analysed separately for each area by univariate and multivariate statistical methods; 5‐yr changes in single species abundances, species number per plot and species composition were tested. Results: Two distinct patterns of change were found: 1. Abundance of several vascular plant species decreased in SE Norwegian Picea forests, most noticeably of species with a preference for richer soils, such as Oxalis acetosella. 2. Abundance of many bryophyte species as well as bryophyte species number per plot increased in forests of both types over most of Norway. Conclusions: The pattern of vascular plant changes is probably a time‐delayed response of long‐lived, mainly clonal, populations to acidified soils resulting from deposition of long‐distance airborne pollutants. The pattern bryophyte changes, with reference to the close link between climatic conditions for growth and abundance changes for Hylocomium splendens established in previous demographic studies, is related to climatic conditions favourable for bryophyte growth. We conclude that many forest understorey plants are sensitive indicators of environmental change, and that the concept used for intensive monitoring of Norwegian forests enables early detection of changes in vegetation brought about by broad‐scale, regional, impact factors.     

Regional and local variation of spider assemblages (Araneae) from coastal grey dunes along the North Sea

Aim This study aims to determine the underlying causes of local and regional patterns of variation in community structure of spiders in coastal grey dunes, and especially whether ecological time constrains the species composition in young and isolated grey dune habitats. Location The study was conducted in coastal dunes from northern France (Boulonnais, Nord‐Pas‐de‐Calais), Belgium (Flemish coastal dunes) and the Netherlands [Amsterdam Water Supply (AWD) dunes and Dunes from the Provincial Water Company North‐Holland]. Methods Spiders were collected with pitfall traps in twenty‐eight grey dune patches in the four areas under investigation. Species composition and environmental parameters (vegetation structure, distance to the sea and the patch‐edge, eolic dynamics and lime richness) were determined. Assemblage composition was related to the regional and local environmental factors with the Primer software package to determine the assemblage‐determining parameters. Differences in species presence were analysed as a function of their habitat preference and distribution range. Results Differences in grey dune spider assemblage structure can mainly be attributed to differences in local sand dynamics and the region. Species from dynamic dunes are mainly present in grey dunes from Belgium and France, while species from non‐dunal xerothermic habitats (chalk grasslands and heathland) occur in both the Boulonnais and the north Holland dune region. These species are absent from geologically young or other xerotherm habitat isolated Flemish coastal dunes. Main conclusion The data show that regional variation in spider assemblage composition results from local landscape characteristics (dynamics in the dune area), the latitude and the connectivity to non‐dunal xerothermic habitats. The strong and moderate geological isolation of dune areas from the Flemish coast and the AWD dunes, respectively, results in the absence of (at least some) species that are primarily bound to heathland and/or chalk grassland. This indicates the importance of ecological time for the assemblage structure. The limited dispersal capacity of the heathland and/or chalk grassland species is probably the main reason for their absence.     

The Netherlands as an environment for chironomid fauna

Commonness and distributional patterns of Chironomidae in The Netherlands are discussed with respect to the occurrence in different water types and the role of some environmental factors. At least 205 taxa were present in The Netherlands. Nine of them became extinct. Lowest numbers of species were recorded in the zone with coastal dunes and in the brackish area. Most species are present in the pleistocene area with sandy soils and variation in relief. The number of species of lotic water are extending those of lentic water. Species wide-spread in The Netherlands are mainly living in eutrophic water. Many species tolerate hypertrophic conditions, especially in running water. Only twenty percent of the species of lotic and lentic water are acid-tolerant. Nowadays species of non-acid, oligotrophic or mesotrophic waters are rare. Oxygen regime in connection with the presence of specific microhabitats are important factors regulating chironomid fauna.     

Vascular plant and bryophytes species representation in the protected areas network on the national scale

The complexity of nature conservation raises questions about biodiversity protection at the level of species as well as their spatial distribution between differently designated nature conservation areas. We have concentrated on comparison of the existing protected areas and recently established conservation initiative areas—Important Plant Areas. We have estimated how well these areas support the protection of two plant groups—bryophytes and vascular plants. We sought answers to the following questions: (a) are there any trends in the distribution of protected bryophyte and vascular plant species in the protected areas network, and (b) does the Important Plant Areas network promote better protection of bryophyte species compared with the existing protected areas network. Our results demonstrated that bryophytes need special care in nature conservation decisions to reach the reasonable conservation target. Important Plant Areas that were targeted to vascular plants have less importance in preserving bryophyte diversity than already existing conservation areas system. Conservation programs like IBA, IPA etc. have their specific tool and outcome to add conservation values to the existing protected areas system.     

Testing a relict distributional pattern of fen plant and terrestrial snail species at the Holocene scale: a null model approach

Aim The term relict refers to a formerly widespread species currently occurring in refugia that provide a persistent combination of specific ecological conditions. In peatlands, direct palaeoecological evidence of relict status exists for some plant species and, in the case of calcareous sediments, for some snail species. We tested whether some species are significantly linked to old calcareous fens at the millennial scale independent of the effect of recent fen area. We focused on three organism groups – vascular plants, bryophytes and land snails – that differ in the degree of preservation of their remains in calcareous fen sediments and in their dispersal ability. Location Western Carpathians (Slovakia and the Czech Republic). Methods The sample sites comprised 47 well‐preserved calcareous fens, from which we compiled complete recent species lists, measured the area and analysed radiocarbon‐dated samples from the deepest sediment and from the beginning of complete deforestation, as indicated by plant and snail fossils. Using the species co‐occurrences in large data sets, we identified calcareous fen specialists and compared their recent distribution patterns against a null model that controlled for the effect of fen area. Results Two land snail species, eleven vascular plant species and no bryophyte species have statistically significant affinities with old fens, independent of the effect of recent fen area. For one bryophyte and one snail, the effects of age and area are not distinguishable. Main conclusions The results for land snails, being abundantly preserved and easily determinable in calcareous fen deposits, are in full accordance with the direct macrofossil evidence. This suggests that our approach indirectly revealed a relict distribution of the species. Identification of species that are significantly linked to ancient localities at the millennial scale has great potential in palaeoecology for the detection of stands with old sediments, and in nature conservation as a tool for the identification of long‐term‐persisting rare species that infrequently colonize young sites and thus deserve priority in the protection of their habitats. From a theoretical perspective, limited dispersal from old to new localities of the same habitat can contribute to spatial effects in biotic assemblages, even at relatively fine scales.     

Responses of Dune Plant Communities to Continental Uplift from a Major Earthquake: Sudden Releases from Coastal Squeeze

Vegetated dunes are recognized as important natural barriers that shelter inland ecosystems and coastlines suffering daily erosive impacts of the sea and extreme events, such as tsunamis. However, societal responses to erosion and shoreline retreat often result in man-made coastal defence structures that cover part of the intertidal and upper shore zones causing coastal squeeze and habitat loss, especially for upper shore biota, such as dune plants. Coseismic uplift of up to 2.0 m on the Peninsula de Arauco (South central Chile, ca. 37.5º S) caused by the 2010 Maule earthquake drastically modified the coastal landscape, including major increases in the width of uplifted beaches and the immediate conversion of mid to low sandy intertidal habitat to supralittoral sandy habitat above the reach of average tides and waves. To investigate the early stage responses in species richness, cover and across-shore distribution of the hitherto absent dune plants, we surveyed two formerly intertidal armoured sites and a nearby intertidal unarmoured site on a sandy beach located on the uplifted coast of Llico (Peninsula de Arauco) over two years. Almost 2 years after the 2010 earthquake, dune plants began to recruit, then rapidly grew and produced dune hummocks in the new upper beach habitats created by uplift at the three sites. Initial vegetation responses were very similar among sites. However, over the course of the study, the emerging vegetated dunes of the armoured sites suffered a slowdown in the development of the spatial distribution process, and remained impoverished in species richness and cover compared to the unarmoured site. Our results suggest that when released from the effects of coastal squeeze, vegetated dunes can recover without restoration actions. However, subsequent human activities and management of newly created beach and dune habitats can significantly alter the trajectory of vegetated dune development. Management that integrates the effects of natural and human induced disturbances, and promotes the development of dune vegetation as natural barriers can provide societal and conservation benefits in coastal ecosystems.