1,721,026 research outputs found
Different ways to success: Plant community trajectories over time and a soil moisture gradient in restored wetlands
Full text linkEcological restoration is one of the most promising strategies to combat historical wetland losses caused by land use changes. Restored areas are ideal sites to study plant succession and changes in ecosystem functions over time. However, little is known about the influence of restoration on plant succession along environmental stress gradients. Knowing the processes and mechanisms driving the succession over time in contrasting abiotic conditions might provide new insight into the ultimate success of an ecological restoration. Relying on long-term vegetation monitoring, we studied the community succession of 4 plant communities along a restored waterlogging gradient in North-East Italy (from high to low soil saturation level): (i) Cladium fens, (ii) low alkaline fens, (iii) Molina wet meadows and (iv) dry meadows. We monitored 23 permanent plots distributed along the gradient, spanning from 1 to 21 years since restoration, and 4 plots as target vegetation (natural habitats). We analysed the changes in plant communities in terms of functional traits, diversity and species composition. We found that exotic and annual species decreased in mature stages of restoration while leaf dry matter content increased over time. Nutrient indicator value and leaf area showed opposite trends at the extreme points of the gradient. Across the successional stages, species richness decreased in Cladium fens and increased in alkaline fens and meadows. Species composition moved toward target vegetation showing contrasting dynamics between different restored habitats. Synthesis and applications. During succession waterlogging stress acts as main abiotic filter, triggering contrasting trajectories of plant communities. This filter seems to be stronger at the extreme points of the gradient generating opposite but faster dynamics than at intermediate conditions. Time and waterlogging promoted a continuous selection of species consistent to target vegetation in terms of richness, functional traits and composition. The evidenced trajectories suggest the need to develop habitat-specific protocols concerning the selection of restoration site and subsequent management decisions, with particular regard to plant communities at intermediate ecological conditions
Evidence of non-structural carbohydrates-mediated response to flooding and salinity in <i>Limonium narbonense</i> and <i>Salicornia fruticosa</i>
No full textIn plant species, the effects of flooding and salinity are commonly studied under controlled conditions in order to understand their acclimation to environmental stresses. Nevertheless, each stress is usually considered separately and laboratory conditions cannot encompass the complexity of the natural ecosystem, often concealing the true plant response. Our work aimed therefore at studying plant responses to flooding and salinity in the field, focusing on two target halophytes and on their reserve organs, i.e. rhizomes of Limonium narbonense and woody stems of Salicornia fruticosa. The physiological response was investigated measuring non-structural carbohydrates (NSCs) and amino acids (AA), and considering the two growing stages of the species, i.e. the growing and the seed ripening seasons. L. narbonense rhizomes showed a larger amount of starch and all measured osmolytes, i.e. NSCs, AA and proline, compared to S. fruticosa woody stem, where plant response to environmental stress seemed linked chiefly to soluble NSCs. The effects on soluble NSCs were mainly driven by flooding and were influenced by salinity only at low flooding stress. The two species showed a contrasting strategy against flooding and salinity based on soluble NSCs, and with a more intense response during the seed ripening season. Large amount of AA, proline in particular, suggested the involvement of these osmolytes in the salinity tolerance in L. narbonense, regardless to the intensity of the stress.</p
There is room for everyone: Invasion credit cannot be inferred from the species–area relationship in fragmented forests
Full text linkQuestions: Land use change, habitat fragmentation and biological invasion represent major drivers of global change that strongly interact to alter ecosystems. Following the breaking apart of forests into smaller fragments or the afforestation of former agricultural lands, biodiversity experiences drastic changes due to species loss and turnover over time. This leads to two important outcomes, namely extinction debt and invasion (colonization) credit, which both reflect the inertia of the system's response to environmental changes. Our study investigated the following questions: Is it possible to infer invasion credit from species–area relationship (SAR) residuals both for native and alien plants? Is there any trend linked with the degree of habitat fragmentation through time?. Location: Somme, Oise and Aisne departments, northern France. Methods: We analyzed the pattern of SARs' residuals for native and alien vascular plant species separately across nine sets of forest fragments that differ by the landscape matrix they are embedded in (i.e., open field, bocage, forest), while considering plant richness, area and age of the 355 forest patches. Results: The relationship between alien and native SARs’ residuals is positive across all landscapes, suggesting a lack of invasion credit. Instead, these results support the “rich get richer” hypothesis, that is a high environmental heterogeneity allows colonization by new species, be they native or alien. Interestingly, the relationship between alien and native residuals depends upon fragment age (i.e., time since patch creation) in the most intensively managed landscapes (i.e., open fields). In the latter, recent forest patches are more prone to alien invasion, as a likely consequence of increased alien propagule pressure (i.e., more sources and vectors for alien plants), increased forest invasibility (i.e., disturbance-induced environmental heterogeneity), and decreased matrix permeability (i.e., natives are more dispersal-limited than aliens). Conclusions: Our study provides new insights into alien species ecology, by showing that (i) it is not possible to infer “invasion credit” from the SAR's residuals; (ii) the invasion rate by alien species in forest fragments increases with their native species richness, and (iii) this relationship depends upon patch age in intensively managed landscapes
Effect of Different Priming Treatments on Quality of Long-Term Stored Seeds of Apium graveolens var. rapaceum DC
No full textIn order to improve germplasm preservation of local cultivar “Friulano”, belonging to Apium graveolens var. rapaceum
(Miller) Gaudin) seed germination of a seed lot, stored for prolonged time at -20°C, was assessed in comparison to that
of a commercial cultivar. In order to increase the seed performance during germination, three different priming pretreatments
(hydropriming for 24 h, osmopriming for 24 h, and osmopriming for 7 days) were performed. Additionally,
seed sowing was undertaken on both potting soil and Petri dish plate condition. Analysis of seed quality was estimated
by measurement of germination percentage, germination energy and the time to reach the 50% of full germination (T50).
The results evidenced that conservation of celeriac dried seeds of “Friulano” cultivar at -20°C for one year maintained a
good level of seed germination (ranging from 38% to 53%), not statistically diverse from the that of commercial cultivar,
for both short hydro- and osmopriming treatments. The germination percentage increased when primed seeds have
been treated in Petri dishes (up to 70%-80%). Furthermore, osmopriming for 24 h positively affected the germination
energy, similarly to that observed in commercial cultivar, being statistically higher compared to hydropriming- and
prolonged osmopriming-treated samples. Accordingly, T50 in short osmopriming treated seeds was low, indicating
that this treatment induced a rapid and uniform germination, being most of the seeds germinated within one week.
In conclusion, these findings represent an important informative step in amelioration of ex situ conservation of a rare
autochthonous horticultural cultivar in North-eastern of Italy
Determining plant diversity within interconnected natural habitat remnants (Ecological network) in an agricultural landscape: A matter of sampling design?
Full text linkIn intensively used and human-modified landscapes, biodiversity is often confined to remnants of natural habitats. Thus, identifying ecological networks (ENs) necessary to connect these patches and maintain high levels of biodiversity, not only for conservation but also for the effective management of the landscape, is required. However, ENs are often defined without a clear a-priori evaluation of their biodiversity and are seldom even monitored after their establishment. The objective of this study was to determine the adequate number of replicates to effectively characterize biodiversity content of natural habitats within the nodes of an EN in north-eastern Italy, based on vascular plant diversity. Plant communities within habitat types of the EN’s nodes were sampled through a hierarchical sampling design, evaluating both species richness and compositional dissimi-larity. We developed an integrated method, consisting of multivariate measures of precision (MultSE), rarefaction curves and diversity partitioning approaches, which was applied to estimate the minimum number of replicates needed to characterize plant communities within the EN, evaluating also how the proposed optimization in sampling size affected the estimations of the characteristics of habitat types and nodes of the EN. We observed that reducing the total sampled replicates by 85.5% resulted to sufficiently characterize plant diversity of the whole EN, and by 72.5% to exhaustively distinguish plant communities among habitat types. This integrated method helped to fill the gap regarding the data collection to monitor biodiversity content within existing ENs, considering temporal and economic resources. We therefore suggest the use of this quantitative approach, based on probabilistic sampling, to conduct pilot studies in the context of ENs design and monitoring, and in general for habitat monitoring
Side Effects of Kaolin and Bunch-Zone Leaf Removal on Generalist Predators in Vineyards
Full text linkIn vineyards, kaolin application and bunch-zone leaf removal (LR) were effective in the control of leafhoppers and Lobesia botrana, but their side effects on generalist predators are still poorly understood. In north-eastern Italian vineyards, the impact of kaolin and LR on species and functional diversity of spiders, as well as the abundance of spiders and generalist predatory insects, was assessed in one vineyard for two consecutive years and in two vineyards for one year. The ecological indices of the spider community were never influenced by kaolin and only in one case were they influenced by LR. At the spider family level, kaolin reduced the abundance of Araneidae, Oxypidae and Salticidae, but only in single cases. In single cases, kaolin reduced the amount of Orius sp. anthocorids and increased that of Scymninae coccinellids, whereas LR increased the amount of Aeolothrips sp. The moderate use of kaolin and the application of LR had negligible and inconsistent impacts on generalist predatory arthropods in vineyards and were therefore, compatible with IPM strategies
First record of naturalization of Erechtites hieraciifolius (L.) Raf. ex DC. (Asteraceae) in Italy
Full text linkThe plant species Erechtites hieraciifolius (Asteraceae) is here reported for the first time in Italy as a naturalized neophyte in the Classical Karst. The species was observed in 2023 in post-fire forest areas burnt by wildfires in the summer 2022. The features of findings suggest for a naturalization of the species with putative invasive character. This novel occurrence highlights the need for additional research to better understand its colonization and expansion, suggesting the need of early eradication actions
Agricultural land use curbs exotic invasion but sustains native plant diversity at intermediate levels
Full text linkUnveiling the processes driving exotic plant invasion represent a central issue in taking decisions aimed at constraining the loss of biodiversity and related ecosystem services. The invasion success is often linked to anthropogenic land uses and warming due to climate change. We studied the responses of native versus casual and naturalised exotic species richness to land uses and climate at the landscape level, relying on a large floristic survey undertaken in North - Eastern Italy. Both climate and land use drove exotic species richness. Our results suggest that the success of plant invasion at this scale is mainly due to warm climatic conditions and the extent of urban and agricultural land, but with different effects on casual and naturalized exotic species. The occurrence of non-linear trends showed that a small percentage of extensive agricultural land in the landscape may concurrently reduce the number of exotic plant while sustaining native plant diversity. Plant invasion could be potentially limited by land management, mainly focusing on areas with extensive agricultural land use. A more consciousness land management is more and more commonly required by local administrations. According to our results, a shift of intensive to extensive agricultural land, by implementing green infrastructures, seems to be a win–win solution favouring native species while controlling the oversimplification of the flora due to plant invasion
Acidophilous grasslands in the Locarnese region (Southern Switzerland): description and classification of main plant communities
Full text linkThis paper presents a phytosociological study of dry and mesophilous meadows and pastures in the Locarnese region (Insubria - Southern Switzerland). Seventy-one vegetation relevés were analysed using both hierarchical classification and nonmetric multidimensional scaling (NMDS) ordination. Seven main clusters were identified and described as follows: (i) xerophytic grasslands on sandy soil dominated by Koeleria macrantha; (ii) mesophilous meadows with Arrhenatherum elatius and Centaurea transalpina; (iii) semi-dry meadows with Chrysopogon gryllus; (iv) semi-dry grasslands with Carex fritschii and Thalictrum minus; (v) nutrient-poor Phyteuma betonicifolium-Festuca nigrescens montane zone grasslands; Nardus stricta grasslands dominated by (vi) Festuca paniculata or (vii) Carex pilulifera. From a phytosociological point of view, a new association named Phyteumo betonicifolii-Festucetum nigrescentis, classified into the Nardo strictae-Agrostion tenuis alliance was proposed. In addition, we confirmed the presence of the Holco-Chrysopogonetum grylli association, within the Bromion erecti, which up to now was provisional only
Landscape and microhabitat features determine small mammal abundance in forest patches in agricultural landscapes
Full text linkIntensification of agricultural landscapes represent a major threat for biodiversity conservation also affecting several ecosystem services. The natural and semi-natural remnants, available in the agricultural matrix, represent important sites for small mammals and rodents, which are fundamental for sustaining various ecosystem functions and trophic chains. We studied the populations of two small mammals (Apodemus agrarius, A. sylvaticus) to evaluate the effects of landscape and habitat features on species abundance along a gradient of agricultural landscape intensification. The study was performed in Friuli Venezia Giulia (north-eastern Italy) during 19 months, in 19 wood remnants. Species abundance was determined using Capture-Mark-Recapture (CMR) techniques. In the same plots, main ecological parameters of the habitat (at microhabitat and patch scale) and landscape were considered. Abundance of A. agrarius increased in landscapes with high extent of permanent crops (i.e., orchards and poplar plantations) and low content of undecomposed litter in the wood understory. Instead, A. sylvaticus, a more generalist species, showed an opposite, albeit less strong, relationship with the same variables. Both species were not affected by any landscape structural feature (e.g., patch shape, isolation). Our findings showed that microhabitat features and landscape composition rather than wood and landscape structure affect populations’ abundance and species interaction. The opposite response of the two study species was probably because of their specific ecological requirements. In this light, conservation management of agricultural landscapes should consider the ecological needs of species at both landscape and habitat levels, by rebalancing composition patterns in the context of ecological intensification, and promoting a sustainable forest patch management
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