Dry Grasslands Research Articles

“Iron chlorosis paradox” in calcicoles and calcifuges from European dry grasslands: A meta-analysis

Iron (Fe) deficiency-related chlorosis (lime chlorosis) and the “paradox of iron chlorosis” in calcicole and calcifuge plants are unresolved problems. We performed a meta-analysis of our previous studies to determine whether calcicoles are more resistant to lime chlorosis than calcifuges are, whether lime chlorosis is Fe chlorosis per se and what is the source of the “paradox of iron chlorosis” in grassland plants. We found that both calcicoles and calcifuges are susceptible to chlorosis when grown on alkaline soil. In general, lime chlorosis does not result from Fe deficiency but is likely associated with manganese (Mn). Additionally, our analyses revealed that Ecological Indicator Values for Europe for soil reaction (R EIVEs) are not random to experimentally determined calcicole/calcifuge behavior but are not straightforward. Ultimately, neither the experimentally determined calcicole index nor the R EIVEs explained the microelemental nutrition of grassland plants in general (except for Zn acquisition), which highlights the need for species ecology-oriented studies to understand these phytocenoses.

Dwarf shrubs may mitigate the negative effects of climate change on spiders by moderating microclimate

Climate change negatively affects arthropod biodiversity worldwide. Mitigating the resulting arthropod decline is a great challenge. Dwarf shrubs in open areas might buffer microclimatic extremities by reducing the solar radiation reaching the ground and weakening air circulation near the soil surface. Forest steppes are mosaics of forests and grasslands covering a vast area in Eurasia. This heterogeneous ecosystem offers the opportunity to study the effect of small habitat features, i.e. dwarf shrubs, in dry grasslands and compare the fauna of rosemary-leaved willow (Salix rosmarinifolia) shrubs with forest patch interiors, open grasslands and their edges. We hypothesized that the dwarf shrub microhabitat has a wetter and cooler microclimate than open grassland and a different spider community composition than other forest-steppe microhabitats. We recorded microclimatic parameters with data loggers, measured soil moisture with TDR and collected ground-dwelling spiders with pitfall traps. We detected the highest soil moisture (6.26 ± 1.21%, mean ± 95% confidence interval) and air humidity (80.19 ± 3.19%) in forests and the lowest in grasslands (4.36 ± 0.65%; 66.59 ± 2.53%, respectively). The warmest microhabitats were grasslands (23.23 ± 0.51°C), whereas the coolest microhabitats were forests (18.92 ± 0.41°C). The distinct microclimate of dwarf shrubs was cooler (21.46 ± 0.41°C) and moister (5.43 ± 0.53%) than the surrounding semi-desert like grassland. Furthermore, we found a different spider community composition and trait state composition of spiders in forests, edges, grasslands and dwarf shrub microhabitats. Forests (9.90 ± 0.95) and edges (11.44 ± 1.27) hosted a higher species richness than grasslands (7.08 ± 4.27) and dwarf shrubs (5.09 ± 1.33). We collected larger spiders on the edges than in dwarf shrub microhabitats. The dwarf shrubs hosted a different microclimate and spider community composition from the grassland. Climate change in the forest-steppe region is assumed to be driven by a combination of warming and drying. In the coming decades, drought frequency and severity are predicted to increase. Woody vegetation, even dwarf shrubs, creates a thermal and moisture heterogeneity that might aid arthropods in buffering macroclimatic warming through behavioural thermoregulation. Therefore, their presence on grasslands can benefit the conservation of specialised grassland arthropods.

Between-year weather differences and long-term environmental trends both contribute to observed vegetation changes in a plot resurvey study.

Repeated surveys of vegetation plots offer a viable tool to detect fine-scale responses of vegetation to environmental changes. In this study, our aim was to explore how the species composition and species richness of dry grasslands changed over a period of 17 years, how these changes relate to environmental changes and how the presence of spring ephemerals, which may react to short-term weather fluctuations rather than long-term climatic trends, may influence the results. A total of 95 plots was surveyed in 2005 and resurveyed in 2022 in dry grasslands of the Kiskunság Sand Ridge (Hungary, Eastern Central Europe), where there has been a significant increase in mean annual temperature during the last decades, while no trends in precipitation can be identified. Db-RDA was performed to reveal compositional changes. The changes in environmental conditions and naturalness state were assessed using ecological and naturalness indicator values. We also compared per-plot richness of all species, native species and non-native species of the old and the new relevés. All analyses were repeated after removing all spring ephemerals. We found clear temporal changes in species composition. Mean temperature indicator values increased, while mean soil moisture indicator values decreased during the 17 years. Also, decreasing per-plot richness was detected both for all species and for native species, while mean naturalness increased. After the removal of spring ephemerals, the compositional changes were less obvious although still significant. The increase in the temperature indicator values remained significant even without the spring ephemerals. However, the decrease in the moisture indicator values, the decrease in the number of all species and native species, as well as the increase in naturalness indicator values disappeared when spring ephemerals were excluded from the analyses. Our study demonstrates that between-year weather differences and long-term environmental trends both contribute to observed vegetation changes.

A Link between Species Abundance and Plant Strategies for Semi-Natural Dry Grasslands.

Due of the potential of species to determine ecosystem properties, it is important to understand how species abundance influences community assembly. Using vegetation surveys on 35 dry grasslands in north-east Slovenia, we defined dominant (8) and subordinate (61) plant species. They were compared on 14 traits to test for differences in community-weighted mean (CWM) and functional diversity (FD). We found that dominants and subordinates differed strongly in their functional traits. Dominants showed higher leaf dry matter content and a more pronounced stress tolerance strategy and were all clonal with a large proportion of species with rhizomes and a rich bud bank, while other species showed a higher specific leaf area, a longer flowering period and more ruderals. For most traits, FD was higher in subordinates. Our results suggest that dominants drive community structure by limited susceptibility to non-competitive processes. Dominants may have positive effects on subordinates by mitigating environmental stressors. Subordinates are able to assemble together by being dissimilar and use different fine-scale niches that are engineered and homogenised by dominants. Our results show that there are fundamental differences in the relative importance of ecological processes between dominant and subordinate plants in species-rich grasslands, which is also important for their conservational management.

Nest site selection and fidelity of European pond turtle (Emys orbicularis) population of Babat Valley (Gödöllő, Hungary)

BackgroundThe conservation of aquatic and semiaquatic turtles requires knowledge of the area and vegetation structure of habitat used for nesting, and nesting migration route. We aimed to survey the effects of habitat features to the nest site selection, nesting success, and test the possibility of nest site fidelity. Our study was carried out at 10 different nesting areas, with special emphasis on data from returning females in a pond system in Hungary between 2014 and 2017.ResultsMost nesting attempts were found in closed sand steppes, uncharacteristic dry and semi-dry grasslands habitat patches. The principal component analysis (PCA) showed that increased sandy soil cover, sunlight and slope were important variables in nest site choice. The increasing PCA first axis score significantly increased the chance of an emergence. The degradation of open steppe vegetation, occurrence of weeds, invasive and disturbance tolerant species have a negative effect on the selection of nest sites. We observed that 96.55% of nests were located within 20 m south of a pine forest at preferred nest site at pond 5, which provided the right incubation temperature through partial shading. The returning females nested significantly closer to the northern pine forest than the single clutch females. Most probably the returning females already has the necessary experience to select the right nesting site. The individually marked females did not choose new nesting areas during the monitored years which suggests nesting area fidelity, but we did not find nest site fidelity.ConclusionThe maintenance of mosaic habitat structure, slowing down the succession process at the nesting area should be basic priorities in European pond turtle conservation programs. We suggested a spatial and temporal scheduling of land management and agricultural work to the local farmers. If the actual nest site is in an agricultural area, all work should be avoided throughout the year. Agricultural machinery should avoid the migration routes of adult turtles and emerged hatchlings during the concerned period. Under strong predation pressure, predator control should be carried out, and use nest protection.

Pogonoloma macrorhizum (Basidiomycota, Agaricales) in Slovak landscape: a distinct fungus of Quercus cerris stands transitional in space and time

The lack of precise data on the environmental requirements of the conspicuous fungus with a northern distribution limit in Slovakia, Pogonoloma macrorhizum, initiated our study. Its identity was verified by sequencing of ITS and 28 S nrDNA regions. The analysis of trophic status by stable-isotope ratio of carbon and nitrogen suggested that the species is probably ectomycorrhizal. For the seventeen sampling sites, environmental data were obtained and information on landscape development and management were retrieved from historical maps and aerial orthophotographs. All these parameters were analysed by multivariate ordination methods. In Slovakia, P. macrorhizum is found in thermophilous to mesophilous stands on acidic soils with a pH ranging from 4.1 to 6.2. These habitats are dominated by Quercus cerris, with non-frequent tree taxa of Carpinus betulus and Quercus petraea agg. The key environmental drivers shaping the habitat of P. macrorhizum were identified as time since deforestation, with the presence of old Q. cerris individuals (former solitary trees of pastures) and soil characteristics. The fungus appears to be a species of transitional habitats historically affected by grazing. These transitions occur between thermophilic and mesophilic sites, including oak forest communities, dry steppic grasslands and forest edges, as well as spontaneously overgrown pastures and forests with a closed canopy. It is regrettable that the Q. cerris stands in Slovakia are under threat, particularly because of felling and the lack of grazing in forests. Furthermore, recent silvicultural practices have resulted in the replacement of oaks (Quercus spp.) by hornbeam (Carpinus betulus) and the formation of closed stands.

Changes in Species Composition, Diversity, and Biomass of Secondary Dry Grasslands Following Long-Term Mowing: A Case Study in Hungary

Changes in Species Composition, Diversity, and Biomass of Secondary Dry Grasslands Following Long-Term Mowing: A Case Study in Hungary

Insular environment-dependent introgression from an arid-grassland orchid to a wetland orchid on an oceanic island

Abstract Adaptive introgression plays a vital role in allowing recipient species to adapt and colonize new environments. However, our understanding of such environment-dependent introgressions is primarily limited to specific plant taxa in particular settings. In Japan, two related orchid species, the autonomously self-pollinating Pogonia minor and the outcrossing Pogonia japonica, typically inhabit dry grasslands and wetlands, respectively. Intriguingly, an island ecotype of P. japonica exists in arid, wind-swept, open sites on volcanic mountain slopes on Kozu Island, in the oceanic Izu Islands. To investigate potential introgression and its implications between P. japonica and P. minor on Kozu Island, we applied a comprehensive approach that included examining morphological traits, genome-wide SNP data, and plastid DNA sequences. We also examined the breeding systems of these species on Kozu Island through artificial pollination experiments to determine if introgression from P. minor has endowed the P. japonica ecotype with selfing capabilities. Extensive sampling on Kozu Island revealed that all P. japonica specimens exhibit signs of introgression from P. minor, suggesting the absence of pure P. japonica populations on the island. Furthermore, the chloroplast haplotypes of the insular P. japonica ecotype consistently match those of P. minor, indicating a predominantly asymmetrical initial hybridization with P. minor acting mainly as the maternal parent in the formation of F1 hybrids. Despite the advantages of self-fertilization in isolated environments, the insular P. japonica does not exhibit autogamy. Consequently, the scarcity of moist habitats, rather than selection pressure for selfing, likely contributes to the observed widespread introgression. Our study strongly suggests that the arid-environment-adapted P. minor has introgressed into the insular ecotype of P. japonica, enabling its successful colonization of arid volcanic mountain slopes of the oceanic island.

Meso-scale environmental heterogeneity drives plant trait distributions in fragmented dry grasslands

Environmental heterogeneity shapes the patterns of resources and limiting factors and therefore can be an important driver of plant community composition through the selection of the most adaptive functional traits. In this study, we explored plant trait–environment relationships in environmentally heterogeneous microsite complexes at the meso-scale (few meters), and used ancient Bulgarian and Hungarian burial mounds covered by dry grasslands as a model habitat. We assessed within-site trait variability typical of certain microsites with different combinations of environmental parameters (mound slopes with different aspects, mound tops, and surrounding plain grasslands) using a dataset of 480 vegetation plots. For this we calculated community-weighted means (CWMs) and abundance models. We found that despite their small size, the vegetation on mounds was characterized by different sets of functional traits (higher canopy, higher level of clonality, and heavier seeds) compared to the plain grasslands. North-facing slopes with mild environmental conditions were characterized by perennial species with light seeds, short flowering period, and a high proportion of dwarf shrubs sharply contrasted from the plain grasslands and from the south-facing slopes and mound tops with harsh environmental conditions. Patterns predicted by CWMs and abundance models differed in the case of certain traits (perenniality, canopy height, and leaf dry matter content), suggesting that environmental factors do not necessarily affect trait optima directly, but influence them indirectly through correlating traits. Due to the large relative differences in environmental parameters, contrasts in trait composition among microsites were mostly consistent and independent from the macroclimate. Mounds with high environmental heterogeneity can considerably increase variability in plant functional traits and ecological strategies at the site and landscape levels. The large trait variation on topographically heterogeneous landscape features can increase community resilience against climate change or stochastic disturbances, which underlines their conservation importance.

Climate and vegetation changes in southern Primorye (Russian Far East) since the Last Glacial Maximum: A quantitative analysis

The climate and vegetation for southern Primorye during the last 21 kyr are studied for the first time in detail using quantitative techniques on high-temporal resolution pollen record. The data obtained showed a clear relationship with global climate events: Last Glacial Maximum, Heinrich 1, Bølling/Allerød, Younger Dryas and the warmest climate event around ca. 8.0 ka. A moderate monsoon-type climate persisted in Primorye during the last 21 kyr. The mean annual temperature did not fall below 0°C. The magnitude of the glacial–interglacial mean temperature difference in southern Primorye was ca. 7°C. Cold and cool temperate climate existed between ca. 21.0 and 11.6 ka and after 4.3 ka respectively. Climate variables of the Last Glacial Maximum were slightly below present-day values, and drier conditions prevailed compared to the late Holocene. Moderately cool conditions with excessive moisture existed during the cold events of the late Pleistocene, i.e., Younger Dryas and Heinrich 1, and in the late Holocene. Humidification did not occur due to heavy rainfall, but due to less evaporation because of low average annual temperatures during these cold events. During the last 21 kyr, there existed dry and wet seasons in Primorye, as at present, associated with monsoon circulation. The summer monsoon was more intense at ca. 16.6 ka, 14.4 ka, 11.6 ka and from ca. 11.0 to 4.3 ka.The southern Primorye during last 21 kyr had a diverse spatial vegetation pattern with conifer and broadleaved deciduous forests of warmer or colder temperate type, dry and humid grasslands, open woodlands and riparian vegetation. Both today and in the past, the heterogeneity of the relief and climate created a diverse vegetation cover. The warmest component, broadleaved summergreen warm temperate trees, had a high proportion from 10.4 to 4.6 ka. Late Pleistocene plant communities, especially during the Last Glacial Maximum, were characterized by a high diversity of dry herbs, which indicates a dry steppe. There are indications of forest-steppe during LGM based on PFT and IPR analyses.

Faecal contamination in China: Trends, sources, and driving mechanisms

Faecal contamination of surface waters is a global public health and economic burden. Here, we constructed a 30-year dataset to analyse the spatiotemporal trends and driving mechanisms of faecal coliforms (FCs) in China. We found that previous national policies to reduce water pollution have significantly improved the quality of surface water and, correspondingly, faecal contamination. However, the downward trend in FC levels has been more gradual than that for physico-chemical pollutants, and this trend may be exaggerated. Our results show that the driving mechanisms of faecal pollution were seasonal and complex. During the dry season, forests and grasslands were the source landscapes that exacerbated faecal pollution; during the wet season, urbanisation dominated, highlighting China's poorly designed drainage systems. Our projections revealed that faecal contamination will continue to worsen from 2022 to 2035, highlighting the need for pollution control. In the future, faecal indicators should be included in routine monitoring, evaluation, and assessment at the national level. Moreover, coordinated design of forest, grassland, and wetland landscapes is recommended for faecal pollution control at the regional level, whereas stormwater-related source control needs to be further strengthened at the urban level.

A new species of Odontarrhena (Brassicaceae) endemic to Greek ultramafics: From taxonomy to metal accumulation behavior

AbstractA new species of Odontarrhena (Brassicaceae) is described from Mount Vourinos in western Macedonia, Greece. The species is restricted to the ridge and the northern slopes of Mt. Vourinos above 1500 m a.s.l. and grows on stony slopes and dry rocky grassland on ultramafic soil with elevated trace metal concentrations. Based on morphological, karyological, and nrDNA sequences, the species is tetraploid with supernumerary B‐chromosomes (2n = 4× = 32 + 2B) and related to the Balkan endemic Odontarrhena decipiens. It differs from the latter mainly by the habit of subshrub with woody base and a denser indumentum of stellate trichomes, resulting in a white‐silvery color of the leaves and shoots. The presence of four degenerate positions in the ITS1 region was detected only in the new species from Mt. Vourinos. Shoot Ni concentrations determined by x‐ray fluorescence analysis and atomic absorption spectroscopy were largely variable (6200–18,700 μg g−1 dw), but always significantly higher than in roots. Hydroponic trials confirmed the typical features of Ni hyperaccumulating plants, such as growth stimulating effect at low metal doses and shoot metal concentration above the hyperaccumulation threshold. The new species of Odontarrhena is a Ni hyperaccumulator with substantial aboveground biomass production, making it a promising candidate for phytomining applications.

Sensitivity of root production to long‐term aridity under environmental perturbations in Chihuahuan Desert ecosystems

Abstract Root production influences carbon and nutrient cycles and subsidizes soil biodiversity. However, the long‐term dynamics and drivers of belowground production are poorly understood for most ecosystems. In drylands, fire, eutrophication, and precipitation regimes could affect not only root production but also how roots track interannual variability in climate. We manipulated the intra‐annual precipitation regime, soil nitrogen, and fire in four common Chihuahuan Desert ecosystem types (three grasslands and one shrubland) in New Mexico, USA, where the 100‐year record indicates both long‐term drying and increasing interannual variability in aridity. First, we evaluated how root production tracked aridity over 10–17 years using climate sensitivity functions, which quantify long‐term, nonlinear relationships between biological processes and climate. Next, we determined the degree to which perturbations by fire, nitrogen addition or intra‐annual rainfall altered the sensitivity of root production to both mean and interannual variability in aridity. All ecosystems had nonlinear climate sensitivities that predicted declines in production with increases in the interannual variance of aridity. However, root production was the most sensitive to aridity in Chihuahuan Desert shrubland, with reduced production under drier and more variable aridity. Among the perturbations, only fire altered the sensitivity of root production to aridity. Root production was more than twice as sensitive to declines with aridity following prescribed fire than in unburned conditions. Neither the intra‐annual seasonal rainfall regime nor chronic nitrogen fertilization altered the sensitivity of roots to aridity. Synthesis. Our results yield new insight into how dryland plant roots respond to climate change. Our comparison of dryland ecosystems of the northern Chihuahuan Desert predicted that root production in shrublands would be more sensitive to future climates that are drier and more variable than root production in dry grasslands. Field manipulations revealed that fire could amplify the climate sensitivity of dry grassland root production, but in contrast, the climate sensitivity of root production was largely resistant to changes in the seasonal rainfall regime or increased soil fertilization.

Dry grasslands in urban areas can harbour arthropod species of local conservation concern and should be prioritised for biodiversity‐friendly mowing regimes

Abstract Although urbanisation is one of the greatest threats to biodiversity, its effect on particular invertebrate groups remains ambiguous on local and landscape scales. We aimed to analyse the effect of urban grassland management on spiders (Araneae) and carabids (Coleoptera: Carabidae), as well as other local and landscape parameters. We investigated 27 grasslands of two different management intensities (‘extensive’: one to two late cuts with removal of biomass [n = 18]; ‘intensive’: three to five mulching cuts [n = 9]) in the city of Karlsruhe, Germany. Pitfall trapping and sweep netting were performed to sample carabids and spiders. Results indicate that urban grasslands in Karlsruhe are inhabited by species‐rich assemblages, including several species of conservation concern (cc). Latter remain mostly restricted to dry grassland. The number of total specimens and of those belonging to species of cc were negatively affected by intensive management. The number of specimens of species of cc further decreased with increasing humidity and in spiders, additionally, by vegetation height. Landscape factors had limited effects, and only isolation of meadows negatively influenced the species richness of carabids (total and of species of cc). Our results demonstrate that conservation of dry grasslands in urban areas is crucial for sustaining local arthropod communities. Dry urban grassland may also act as a refugium for species of cc and mitigate the global insect crisis on a local and regional scale. In conclusion, biodiversity‐friendly mowing regimes should be applied on a broader scale in urban areas and target especially dry grassland plots. In addition, increasing connectivity and permeability of the urban matrix assist the colonisation by species of cc.

Dry grasslands and thorn-cushion communities of Armenia: a first syntaxonomic classification

Aim: To provide the first syntaxonomic, plot-based classification of the dry grasslands and thorn-cushion communities in Armenia. Study area: Armenia. Methods: We sampled 111 vegetation plots (10 m2) and recorded environmental and structural parameters. We collected additional 487 relevés from surrounding countries for a broad-scale comparison. We used modified TWINSPAN to derive a syntaxonomic classification system, whose units were then compared among each other regarding species composition, structure, site conditions and distribution. Results: The classification of Armenian vegetation plots resulted in a 12-cluster solution. Unsupervised classification of the broad-scale dataset yielded five main groups, which were used for the high-level syntaxonomic assignments of the Armenian data. We assigned about half of the plots of the Armenian dataset to the Festuco-Brometea, while the remaining represented a potential new class, preliminarily called “Ziziphora tenuior-Stipa arabica grasslands”. Most of the syntaxa below class level are new to science, therefore we provide formal descriptions of three orders (Plantagini atratae-Bromopsietalia variegatae, Onobrychido transcaucasicae-Stipetalia pulcherrimae, Cousinio brachypterae-Stipetalia arabicae), four alliances (Acantholimono caryophyllacei-Stipion holosericeae, Artemision fragrantis, Onobrychido michauxii-Stipion capillatae, Onobrychido transcaucasicae-Stipion pulcherrimae) and six associations. We found significant differences in the topographic, climatic and soil characteristics, and structural parameters, species life forms and distribution range types between the grassland types at different syntaxonomic levels. The mean species richness was 47.3 (vascular plants: 46.8, bryophytes: 0.4, lichens: 0.1). Conclusions: We found remarkable differences of the Armenian dry grasslands from the previously known units and described most of the higher syntaxa and all the associations as new to science. Our study provides arguments for a potential new class of Ziziphora tenuior-Stipa arabica grasslands separate both from the Euro-Siberian Festuco-Brometea and the Anatolian Astragalo-Brometea. Finally, we found plot scale richness of vascular plants clearly above the Palaearctic average of dry grasslands and that of non-vascular plants clearly below, which calls for further biodiversity analyses. Taxonomic reference: Euro+Med (2023) for vascular plants, Hodgetts et al. (2020) for bryophytes, Nimis et al. (2018) for lichens except for Xanthoparmelia camtschadalis (Ach.) Hale. Abbreviations: EDGG = Eurasian Dry Grassland Group; DCA = detrended correspondence analysis; ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); TWINSPAN = two-way indicator species analysis.

Soil and Vegetation Characteristics of Grassland have a Greater Influence on the Abundance and Diversity of Earthworms than the Mowing Intensity in a Managed Nature Reserve

Effects of mowing on vegetation parameters have been well studied. However, less is known about mowing effects on soil fauna and if soil properties alter this. We investigated earthworm communities in a long-term experiment 14 years after its establishment in 5 dry, fresh and moist grassland plots located in the Natura 2000 site Lainzer Tiergarten near Vienna, Austria (238–402 m a.s.l., 48°10′ N, 16°12′ E). The grasslands were either mowed once a year or every second year, or not mowed since being established. Earthworms were assessed using the non-destructive octet electro-shocking method. Additionally, vegetation composition, soil conductivity, temperature and moisture were assessed. We found 13 earthworm species across all treatments, although their abundance was generally low with 6.1 ± 4.7 worms m−2. The total earthworm abundance and species diversity was higher in dry compared to fresh and moist grasslands but was not affected by mowing frequency. Endogeic earthworms (Aporrectodea caliginosa, Aporrectodea rosea) and epigeics (Lumbricus rubellus) were more tolerant to mowing than anecics (Lumbricus terrestris, Allolobophora longa). Since plant species richness was highest in annually mown grasslands and earthworm species richness was positively related to plant species numbers, we recommend regular, low-input management to promote above- and belowground biodiversity in these grasslands.

Palaeoenvironmental reconstruction of poorly stratified sites using malacological assemblages of archaeological features: A case study in Reims (NE France)

At the 53 ter rue de Louvois, in Reims, a number of human settlements dating from the Mesolithic period to the Early Middle Ages have been uncovered. Located on a footslope, these successive settlements are evidenced by archaeological features such as pits and ditches, which broadly appear at the same stratigraphic level. These features of different ages therefore provide valuable opportunities for sedimentary records in a context where natural stratification is poor. The examination of sedimentary archives sourced from archaeological features reveals distinct environmental phases interspersed with hiatuses stemming from the intermittent human habitation of the site. The initial phase provides insights into the early Holocene period, particularly during the First Mesolithic, illustrating the emergence of a pioneering semi-forest environment between around 9200 and 8200 cal. BC. Subsequently, Phase 2a, dated between 7050 and 6250 cal. BC, witnesses the expansion of deciduous forests during the Second Mesolithic. This expansion peaks during the Middle Neolithic (4300–3500 cal. BC), despite the construction of an enclosure in Phase 2b. The site is later cleared, at an unknown date between the end of the Middle Neolithic and the beginning of the Iron Age, probably during the late Bronze Age, between 1300 and 800 cal. BC. Phase 3 is thus characterised by the dominance of a dry grassland environment from the Hallstatt period through the early Middle Ages. This regional example illustrates the remarkable potential of malacological remains for reconstructing palaeoenvironments in poorly stratified contexts, as close as possible to human settlements and outside wetlands, the main sites for palynological investigations.

A causal trait model for explaining foliar water uptake capacity

AbstractQuestionsPlants largely vary in their capacity for foliar water uptake (FWU), that is, the capacity to increase leaf water content by directly absorbing water from leaf‐wetting events. Climate change will reduce leaf wetting and increase drought events. Therefore, we need a better understanding of the underlying traits and mechanisms that facilitate FWU.LocationSeasonally dry tropical montane grasslands in Brazil (Campos de Altitude).MethodsWe measured FWU and leaf traits related to wettability, surface conductance, water potential and water storage on up to 55 plant species. By using Direct Acyclic Graph theory and Bayesian modelling, we tested how those leaf traits affect FWU.ResultsWe found that stomatal conductance largely explained interspecific variation in FWU, which was also favoured in species with hydrophilic leaves, high cuticular conductance, more negative leaf water potentials, low dry‐matter content, isohydric behaviour, and more elastic cell walls.ConclusionsDue to the existence of trade‐offs, not all species exhibit an optimal combination of traits that favours FWU. Instead, co‐occurring species have achieved a similar capacity for FWU through distinct trait combinations. Consequently, species engaged in FWU may exhibit differential vulnerabilities to climate change as they can cope with drought using other strategies beside FWU.

Evolution of karst rocky desertification and its response to land use changes in different geomorphologic environments

Studying the evolution of karst rocky desertification (KRD) in control areas of diverse geomorphologic types and its correlation with land use provides valuable insights for identifying priority areas and implementing effective treatment measures. Employing Remote Sensing (RS) and GIS, this research quantitatively examines the evolution of KRD and its relationship with land use in the karst mountain and gorge areas of Guizhou Province over the period 2010 to 2020. The findings reveal continuous improvement in KRD across the study areas, albeit with noticeable regional disparities. Notably, the karst mountain region exhibited significantly higher change areas and rates of KRD, non-KRD, light KRD, and moderate KRD compared to the gorge area, underscoring better desertification control in the former region. A discernible correlation emerges between different karst geomorphologic types, the distribution and changes in land use types, and the evolution of KRD. Land use change emerges as a pivotal factor influencing the improvement of KRD in these areas. Changes in land use patterns corresponded with a decrease in KRD in dry land, other woodland, grassland, and bare land across both regions. However, the response of KRD to land use patterns varied across control areas with different geomorphologic environments, resulting in geographical differentiation in KRD evolution. Key land use conversions, notably from shrubland to forestland and dry land to garden land in the gorge, and shrubland to forestland in the mountain, contributed significantly to KRD dynamics in these regions. Notably, in the gorge area, KRD primarily occurred in garden land, other woodland, dry land, and grassland. In contrast, in the mountain area, KRD was prevalent in shrubland, dry land, and grassland, highlighting distinct responses and contributions to its evolution. The study observes substantial land use change in KRD-improved areas, particularly in the gorge region. Notably, the responsiveness of KRD to woodland conversions (shrubland, forestland, other woodland) varied across different geomorphologic environments. The dynamics of rocky desertification occurrence (RDO) and the occurrence structure of KRD in various land use types exhibited significant differences between the two regions. The gorge area demonstrated generally higher RDO, with a relatively stable and simpler occurrence structure of KRD compared to the more dynamic and varied structure observed in the mountain area. The sequencing of KRD occurrence in both areas displayed stability in specific land use types, with varying intensities noted between them.

Competition between alien and native species in xerothermic steno-Mediterranean grasslands: Cenchrus setaceus and Hyparrhenia hirta in Sicily and southern Italy

AbstractPerennial dry grassland communities, vital for plant biodiversity conservation in the Mediterranean, often harbor rare and endangered species. However, these habitats face threats, including the invasion of alien species. Cenchrus setaceus, a highly invasive grass, is spreading in the Mediterranean region. Historical records and observations document its establishment and invasiveness across various Italian regions. This study investigates the impact of C. setaceus on native grasslands dominated by Hyparrhenia hirta. We assessed the impact of C. setaceus invasion on plant biodiversity in Sicily and southern Italy, and we identified and characterized plant species’ composition using Ellenberg indicator values. The intention to analyze species richness, diversity, and ecological indicators is also emphasized. Starting from the use of the phytosociological method, multivariate analysis and Ellenberg indicator values to assess the impact of C. setaceus on grasslands composition were considered. There are several similarities and differences in diversity, floristic composition, and ecological traits between the two grassland types. A deep comparison with central European studies and evaluation of the impact of C. setaceus on species richness and community dynamics in Mediterranean habitats were concluded. Although C. setaceus is invading native grasslands, it does not drastically reduce species richness. The ecological implications of the invasion are explored, urging ongoing monitoring and collaborative efforts for effective conservation. The importance of interdisciplinary cooperation is highlighted to address the threat of invasive species and sustain the biodiversity of Mediterranean grasslands.