Floodplain Forests Research Articles

The lichen genus <i>Rinodina</i> (Physciaceae) in New Brunswick, Canada

Fifteen species of the crustose lichen genus Rinodina are confirmed in New Brunswick, Canada. We report four corticolous species, Rinodina pachysperma, Rinodina populicola, Rinodina septentrionalis, and Rinodina tenuis, and the saxicolous Rinodina tephraspis in the province for the first time. A previous report of Rinodina granuligera is based on a specimen that we have re-identified as Rinodina cinereovirens. We note distinguishing characteristics, habitats, substrata, relative abundance, and biogeographic relationships of each species and provide an identification key and distribution maps. The most frequently occupied phorophytes (tree substrata) are Sugar Maple (Acer saccharum), Yellow Birch (Betula alleghaniensis), and Eastern White Cedar (Thuja occidentalis). Some species are closely associated with particular habitats, phorophytes, or both. For example, we found R. pachysperma only in floodplain forests dominated by Silver Maple (Acer saccharinum), and R. tenuis only on Eastern White Cedar in wet cedar-dominated stands. In contrast, we recorded Rinodina freyi on numerous phorophyte species in a relatively wide range of habitats. Other than Eastern White Cedar and Balsam Fir (Abies balsamea), conifers are rarely colonized by Rinodina species in New Brunswick. Most Rinodina species are probably not currently of conservation concern in the province. However, R. cinereovirens is known from only two collections, one dating from 1902. The other, from 2007, was on Black Ash (Fraxinus nigra) in a swamp forest next to an active peat-mining operation. The expected devastation of ash species by the invasive Emerald Ash-borer (Agrilus planipennis) is a further threat to this occurrence and to any lichens for which ash may be an important phorophyte.

Alpha diversity of lichenized and aphyllophoroid fungi in two 1ha forest plots in the Samursky National Park (Republic of Dagestan, Russia)

Aim. The results of the inventory of species composition of epiphytic lichens and aphyllophoroid fungi on two 1 ha sample plots in lowland floodplain forests are presented. Such integrated studies of these groups of organisms are poorly known. Fungi, including lichenized fungi, are essential components of forest ecosystems. Data on their diversity and substrate distribution can provide important information on the condition and biological value of the forests studied. Material and Methods. The main method of the fieldwork was the "1‐ha method". For the alpha‐diversity study, two 1‐ha sample plots were established in well‐preserved forest areas: the first one in a site of mixed broad‐leaved forest with lianas, and the second one in communities dominated by Carpinus betulus and Quercus robur. The specimens were collected from all variety of woody substrate within plots in spring and autumn 2023. Results. We have revealed 89 species of lichens and 60 species of aphyllophoroid fungi. The lichen families Arthoniaceae, Lecanoraceae, Physciaceae, Ramalinaceae and Roccellaceae contain 47.2 % of all species. High proportion of lichens with Trentepohlia photobiont (29.2 %), significant number of Arthoniomycetes (Arthoniaceae, Lecanographaceae, Roccellaceae) and crustose lichens (75.3 %) have been noted. Among the aphyllophoroid fungi identified in the sample plots, 11 species are new to Dagestan, including three species (Antrodia leucaena, Coronicium gemmiferum, Steccherinum litschaueri) recorded for the Caucasus for the first time. Fourteen species are new to the Samursky National Park. Conclusion. The study of alpha diversity and substrate preferences of xylobionts revealed the richest and most specific phorophytes, as well as some ecological features of the surveyed plots. Most of the species were found on the bark and wood of Carpinus betulus, Populus alba and Quercus robur. The majority of species reported for the first time for the region have been recorded on these tree species. We expand the number of known species on Populus alba, on which only few species were previously known. High proportion of lichens with the Trentepohlia photobiont and the predominance of crustose species were revealed. In terms of basidiomata morphology, corticioid fungi dominated over polypores and clavarioids in general. The leading ecological and trophic group of aphyllophoroid fungi are saprotrophs. Revealed features indicate a significant contribution of the wood of the main forest‐forming tree species to the preservation of the species richness of myco ‐and lichen biota.

Habitat preferences and phytocoenotic range of Reynoutria japonica Houtt. in Ukraine

Based on vegetation plots extracted from phytosociological databases and literature sources, the current distribution of Reynoutria japonica in Ukraine was assessed in terms of habitat preferences and phytocoenotic affiliation. It has been found that R. japonica in Ukraine is spread across four habitat types: anthropogenic areas, floodplain forests, shrublands, and gravel bars. The most frequent occurrences of the studied species were found in anthropogenic habitats covered by mesophilous nitrophilous tall herbs. Within the floodplain habitats, R. japonica was most frequently found in temperate riparian willow-poplar forests and temperate riparian hardwood forests. R. japonica is much less frequently related to shrub habitats and gravel bars. It occurs with different covers, reaching its maximum values on anthropogenic sites. The analysis of the phytocoenotic range of species showed that it is a component of the vegetation belonging to the classes Epilobietea angustifolii, Salicetea purpurea, Alno glutinosae-Populetea albae, and Thlaspietea rotundifolii. The analysis of habitat types and plant communities with the participation of R. japonica in Ukraine showed that the species occurs in ecological environments closely related to those that are characteristic of the species in its native range – mesophylous soils, rich in nutrients, which is a favorable factor in the process of species accelerated adaptation to new territories.

ОЦЕНКА СОВРЕМЕННОГО СОСТОЯНИЯ РАСТИТЕЛЬНОГО ПОКРОВА Г. ОБЛУЧЬЕ ПО МУЛЬТИСПЕКТРАЛЬНЫМ ДАННЫМ

A sustainable development of regional towns and small settlements demands the urban modern landscape infrastructure study and assessment. For this purpose, geoinformation systems and remote sensing data are widespread used. The aim of the study was to analyze the green spaces in the small town of Obluchye (Jewish Autonomous region) using multispectral data with an assessment of indicators of the town sustainable development. The sources of information were as follows: Sentinel-2A multispectral products, the Rules of land use and development for Obluchye, field research materials, ICARP FEB RAS stock materials, special literature. The identification and analysis of green spaces distribution in Obluchye are based on calculation results of the normalized vegetation index (NDVI). It is stated that the NDVI value of 0.55 or more is the boundary value for the allocation of green spaces in Obluchye; 0.75 or more - for woody vegetation. The NDVI boundary value of 0.55...0.74 is for herbaceous and shrubby vegetation on lawns, unsettled areas, as well as for natural and produced meadows. The NDVI values of 0.75 or more in the image determine the forest vegetation of the Obluchye recreation zone, tree and shrub thickets along riverbeds and floodplain forests, and woodlands in the town built-up zone. The green spaces distribution across the town functional zones is uneven. The high and very high landscaping areas are characteristic of the Obluchye periphery and correspond to the zones of recreational and residential development. In most cases, tree plantations are located in a recreational area, mainly outside the town. However, all urban development zones have high values of landscaping average level (from 71 to 93%). The calculated indicators of sustainable development in Obluchye show, on the one hand, a significant exceeding level of landscaping (53%), as compared to the established norms (at least 40%). On the other hand, the share of green areas of common use in the total area of green spaces in Obluchye is very low – only 1.6%. Thus, there is a need in a qualitative improvement of green infrastructure in the town of Obluchye.

First Report of Phytophthora citrophthora Causing Leaf Necrosis and Terminal Shoot Dieback on Asimina triloba (Pawpaw) in a Virginia Floodplain Forest

Asimina triloba (pawpaw) is a shade-tolerant, understory, deciduous tree in the family Annonaceae that is native to 26 states in the Eastern United States, with a range from the Florida panhandle to New York, west to Iowa and Nebraska, and south to Texas. On 12 June 2022, in a floodplain forest along the James River near Richmond, Virginia, a group of three A. triloba saplings about 1.0 to 1.5 m tall were observed with leaf necrosis, terminal shoot dieback, and leaf drop. Symptomatic tissue was cultured on selective media, and isolate DB22-4 was identified as Phytophthora citrophthora using morphological and molecular methods. Segments of the ITS and COX1 loci were deposited in the GenBank database under accession numbers OQ703042 and OQ834750, respectively. Koch's postulates were fulfilled in an unwounded, attached-leaf assay by inoculating 20 leaves on five healthy saplings. To the authors’ knowledge, this is the first report of P. citrophthora causing terminal necrosis and leaf drop on A. triloba in a nursery or a natural ecosystem. Additional studies are needed to understand which Phytophthora spp. cause disease on A. triloba, as well as the environmental and physiological factors that favor infection in the forest under natural conditions.

Catasetum queirozii (Orchidaceae: Catasetinae): uma nova espécie da Amazônia brasileira

ABSTRACT This study presents a new orchid species of the genus Catasetum belonging to the group of species with symmetrical and parallel antennae. It was found in terra-firme and floodplain forests in the Brazilian states of Amazonas and Pará. We provide a formal description of the new species, images, and notes on distribution, habitat, phenology, flower visitors and preliminary conservation status. We compare it with C. cristatum and C. barbatum, both sympatric and morphologically most similar to the new species. It was preliminarily classified in the Endangered (EN) category according to IUCN criteria based on the extent of occurrence, area of occupation, number of occurrence locations and the risks that the known populations are exposed to (deforestation and predatory collection).

Influence of forest structure and soil chemistry on ants, land snails, and beetles in Balkan floodplain forests: Examining species richness and habitat preferences

Influence of forest structure and soil chemistry on ants, land snails, and beetles in Balkan floodplain forests: Examining species richness and habitat preferences

Vegetation affinity of Epipactis albensis (Orchidaceae) in central Europe

Epipactis albensis is an obligate autogamous orchid species which is widely distributed in central European countries. However, its phytocoenological affinities are not well known. They were investigated in this study based on 17 phytosociological relev?s from the Czech Republic, Slovakia, and Poland obtained from the available literature and database sources, where the species has its centre of occurrence. The cluster analyses revealed three groups of vegetation types belonging to the hardwood floodplain forests of the Fraxino-Quercion roboris alliance, the riparian alder forests of Alnion incanae and the beech forests of Fagion sylvaticae. Brachypodium sylvaticum, Circaea lutetiana, Geum urbanum, and Urtica dioica (frequency 76%), followed by Dactylis glomerata agg. and the alien plant Impatiens parviflora (65%) are the most co-occurring species. This phytosociological study has highlighted the need for further and more detailed research supported by the collection of new vegetation data from across the range of E. albensis.

Amphibians of the genus Rana in the steppe zone of Ukraine: population status, distribution, and ecological features

Frogs of the genus Rana Linnaeus, 1758 are represented in the steppe zone of Ukraine by their southernmost populations. The distribution of brown frogs in the steppe zone of Ukraine is closely related to the floodplain forests of major rivers (Dnipro, Dnister, Danube, Southern Bug, Oril, Samara, Donets, etc.). The paper presents for the first time data on the distribution, ecological and population features, habitats, specifics of reproduction and development of brown frogs. New habitats of R. arvalis were found in the floodplain habitats of the lower reaches of the Dnipro River in Kherson Oblast and populations were confirmed in Dnipropetrovsk and Kirovohrad oblasts. The southern border is intrazonal. The new southernmost localities are described from Kherson Oblast (the villages of Pravi Solontsi and Krynky). The habitats belong to forest type habitats (G). The mean abundance of frogs is 5–10 individuals per 1 km of route and can reach 50 individuals per 10 m2 during the spawning season (Black Forest Reserve, Kirovohrad Oblast). The breeding season is in late March to early April at air temperatures of +3–4 to 8–12°C and water temperatures of +7–9°C. The mating process is short. The Dnipro isolates of R. arvalis may be of relict nature, form a series of refugia and be of important historical and indicator value. Given the overall reduction in the range of R. arvalis within its core area, active populations in the south can be valuable reserves for the conservation of the species and the sustainability of steppe biodiversity. Two other species, R. temporaria and R. dalmatina, were not found and their habitat within the steppe zone has not yet been confirmed. As typical forest species, they are common closer to the forest-steppe zone. Given the current state of brown frog populations in the steppe zone of Ukraine, their low numbers and isolation, they need regional protection along with their habitats. The issue of determining the origin of the identified populations in order to form an idea of the historical and genetic value of the southernmost populations of brown frogs in Ukraine remains promising.

Fritillaria meleagris L. (Liliaceae) in the Kharkiv Region: ecological preferences, conservation problems

Fritillaria meleagris L. is a рalearctic species with a disjunct distribution. It is protected at the national level in Ukraine, listed as "vulnerable" in the Red Data Book. Most of the data on the species distribution, as well as on the status and stability of its populations, have been obtained for the Carpathian region. Much less information is available for F. meleagris in the Forest Steppe, especially for its left-bank part. The article presents the results of the study of the peculiarities of F. meleagris distribution in the Kharkiv Region and provides information on the structure of coenopopulations and their ecological and coenotic preferences. Problems and prospects for this species conservation are also considered. The studies cover the biotopes of the Merla River valley and its tributary, the Merchyk River (the Dnipro River basin) in an area of more than 35 square km. In the Kharkiv Region, the F. meleagris coenopopulations were found mainly in grass-type biotopes. These are usually secondary post-forest meadows of the Molinio-Arrhenatheretea Tx. 1937 class. Only one coenopopulation is located in a tree-type biotope (mixed floodplain forest with Quercus robur L., Ulmus laevis Pall., Alnus glutinosa (L.) Gaertn., Salix alba L., Padus avium Mill., Populus аlba L., P. deltoides Marshall, P. tremula L., Acer negundo L., А. tataricum L., A. campestris L., without a pronounced dominant). The specificity of the ecological regimes of the studied localities of F. meleagris has been clarified by the phytoindication method. As a rule, they are damp (less often, fresh) forest-meadow habitats with full, but uneven (temporarily excessive) wetting of the root layer of the soil. The soils are moderately aerated, weakly acidic (pH 5.5–6.5), enriched with salts, but with insignificant carbonate content, and often relatively poor in terms of mineral nitrogen. The climate is characterized by submicrothermal conditions with signs of subaridity and subcontinentality. We have not detected any significant variability of conditions (both edaphic and climatic) in the studied localities. They are more or less optimal for the existence of F. meleagris. In all the F. meleagris localities studied, the change in the hydrological regime due to the reclamation of floodplain remains a risk factor but does not pose an immediate threat. The existence of forest coenopopulations in glades is threatened by overgrowth of trees and shrubs (the invasion of Populus tremula and Acer negundo is particularly dangerous). The decrease in the number of meadow coenopopulations is a result of plowing and burning. Currently, in the Kharkiv Region, F. meleagris is protected in Slobozhanskyі National Nature Park (1 locality) and in Kapranskyі Botanical Reserve of local importance (11 localities). Monitoring of the existing localities outside the protected areas and their inclusion into the expansion zone of the Slobozhanskyі National Nature Park is an important condition for their preservation.

Seasonal Dynamics in Mycorrhizal Colonization and Fine Root Features of the White Poplar (Populus alba L.) in Natural Temperate Riverside Forests with Two Contrasting Soils

Fine roots are the most dynamic and physiologically active components of belowground tree organs. However, much remains unknown regarding the changes in fine root morphological characteristics during mycorrhizal colonization, especially in natural sites. The aim of this study was to analyze seasonal heterogeneity in fine roots and the mycorrhizal colonization of mature white poplar (Populus alba L.) trees under different soil conditions. Two floodplain forests were selected in Central Europe (Poland), which differed in soil moisture and structure. Fine roots were sampled during one growing season from the upper soil layer. Poplars were characterized by dual mycorrhizal colonization on one root system. It was, therefore, possible to investigate the contribution of two mycorrhizal types (arbuscular mycorrhiza—AM; and ectomycorrhiza—ECM) in response to different habitat conditions. The season was shown to be significant for all fine root features, as well as the degree of mycorrhizal colonization. Roots were better adapted to a drier habitat with a greater proportion of sand, mainly due to a reduction in the fine root diameter (FRD), while other root characteristics did not differ significantly. The degree of mycorrhizal colonization (RLC) and the proportion of arbuscular mycorrhizal structures (AM) were significantly and negatively correlated with the soil water content. A mutual competition between arbuscular mycorrhizas and ectomycorrhizas for poplar roots was also observed, particularly with respect to the season, site, and soil moisture. Changing environmental conditions (especially soil moisture) contribute not only to the morphological and functional changes of fine roots but also to changes in the proportion of arbuscular mycorrhiza and ectomycorrhiza. Understanding the mechanisms of adaptation of tree roots to changing environmental conditions is especially important in the context of climate change.

Evaluation of the management potential of timber resources in clearwater floodplain forests in the Amazon using growth models

The Amazonian clearwater igapós are poorly studied floodplain ecosystems that are mainly covered by forests and are undergoing massive threats due to changes in land use and climate. Their hydrochemical characteristics and edaphic conditions fall between those of the eutrophic várzea floodplains on whitewater rivers and those of the oligotrophic igapós on blackwater rivers. Previous studies have indicated the management potential of timber species in the highly dynamic várzea floodplains due to the fast tree growth and high forest productivity. Timber resource management, however, is not recommended for the blackwater ecosystem because of its slow dynamics and high vulnerability to disturbances. For clearwater igapós, information on the potential for sustainable management of timber resources is lacking. In this study, we modeled the growth in diameter, height, and volume to derive species-specific minimum logging diameters (MLD) and felling cycles (FC) for eight merchantable species in the clearwater igapós of the Branco and Tapajós rivers in the northern and southern Amazon Basin, respectively. Diameter growth was modeled by analyzing the tree rings that are annually formed in the Amazonian floodplains as a consequence of the regular and predicable long-term flooding. Growth modeling followed the guidelines of the Growth-Oriented Logging (GOL) concept, with the adjustment of diameter growth improved by applying nonlinear mixed-effects regression. MLDs varied from 36 to 90 cm and FCs ranged from 6 to 21 years, which diverges from the standards of Brazilian logging regulations (MLD: 50 cm; FC: 25–35 years). This indicates the potential for timber resource management, which should be tested and introduced at small scales, integrated in protected areas to stepwise promote the sustainable management of these natural resources by traditional communities to increase their income and the conservation of this ecosystem.

The vegetation history of Lake Mert and its surroundings for the last 6600 years (Kırklareli, NW Türkiye)

The primary aim of this study is to determine the Middle-Late Holocene vegetation history of the İğneada Longoz (Floodplain) Forests around Lake Mert, located in Kırklareli, using high-resolution palynological analysis conducted on the MRT-04 core. Pollen analyses was performed on sediment samples collected from 67 different levels within the core. Pollen counting and identification were performed using a Leica DM750 light microscope, with a minimum of 500 terrestrial pollen grains counted per sample. The age of the lake was determined to be 6600 years old through radiocarbon dating of the core. According to the findings from the pollen analysis, deciduous mixed oak forests have dominated the region in and around Lake Mert for the past 6600 years. Within these mixed oak forests, Quercus cerris type (deciduous oaks) is predominant, with notable contributions from Fagus, Carpinus, Corylus, and Tilia. This forest composition has displayed a consistent pattern, except for changes attributed to the expansion of temperate species and human influences. The distribution of mixed oak forests began to decline around 1360 BP, coinciding with a significant increase in the presence of Alnus, Fraxinus, and Ulmus. These trees are characteristic species of floodplain forest and indicate the initiation of the formation of the İğneada Longoz Forests after 1360 BP. Furthermore, around 420 BP, there was a substantial decrease in the pollen percentages of Quercus and Fagus. During this period of declining mixed oak forests, Plantago and Ambrosia appeared for the first time in the pollen diagram. The reduction in arboreal plant taxa and the rise of herbaceous taxa such as Plantago, Ambrosia, and Poaceae, which serve as indicators of human impact, signify the conversion of forested areas into agricultural and pasture lands.

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems. The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L. and have a major impact on the quantity and quality of pollen and seeds. In this study, we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022. Inflorescences were collected from 105 trees (pollen production), pollen from 125 trees (pollen viability), and seeds from 53 trees (seed quality) in two seed orchards and in one floodplain forest in southern Germany. Not all parameters were examined at every site every year. The average pollen production per tree was estimated at 471.2 ± 647.9 billion pollen grains. In addition, we found that a high number of inflorescences did not equate to high pollen production per inflorescence. Pollen production of healthy and diseased trees did not differ significantly, although only 47% of severely diseased male trees (vs. 72% for healthy trees) produced flowers. With regards to pollen viability, the TTC test showed an average viability of 73% ± 17%. Overall, there was a slight tendency for diseased trees to have less viable pollen. However, a significant difference could only be calculated for trees in the floodplain forest. The percentage of germinable seeds in 2018 was 38% in the floodplain forest and 57% in one of the seed orchards. The percentage of viable seeds (TTC test) ranged from 17 to 22% in the orchards in 2020. Non-viable seeds were usually heavily infested by insects. In general, seed quality was not significantly different between healthy and diseased trees. Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality. Nevertheless, the fact that hardly any flowering was observed, especially for trees that were seriously affected, suggests a negative effect of ash dieback on reproductive performance. Thus, severely diseased trees will transfer their genes to a smaller extent to the next generation.

Species composition and ecological groupings of birds of extrazonal transformed landscapes of Yenisei Siberia in the spring and summer period

The article presents the results of a pilot study conducted in May–June 2022 in the places of interpenetration of the Krasnoyarsk forest-steppe and subtaiga, where extrazonal transformed landscapes were formed. An important role in this was played by such factors as the location of the territory on the border of natural zones, the dismembered hilly-rocky terrain, active human economic activity, which also caused the high mosaic of biotopes. As a result, there is an overlap of ranges of typically forest and steppe bird species, as well as their nesting in close proximity to each other, which is explained by their ecological specialization. During this period, 105 species and subspecies of birds belonging to 13 groups were noted. All the diversity is distributed by ecological groups that correspond to the large biotopes identified in the study area: small-leaved birch and mixed forests; forest edges, felling and chopping; coniferous forests; high-stemmed and shrubby floodplain forests; residential landscapes; wetland complex; high-grass and low-grass open areas. Some phenological data, information on the biotopic placement, abundance and nesting of birds collected in the process of route hiking are presented.

Species and Coenotic Diversity of the Floodplain Forest Communities in Northeast Russia

Species and Coenotic Diversity of the Floodplain Forest Communities in Northeast Russia

Forest Litter Features in the Floodplain Forest of the Bolshaya Kokshaga Reserve

Forest Litter Features in the Floodplain Forest of the Bolshaya Kokshaga Reserve

Current state of trees and shrubs vegetation conditional references linden-ash oakwoods flood places of Dniprovsk Prisamarya

Natural oakwoods are considered one of the main centers of biodiversity of flora and fauna in Europe and an important agent of providing a wide range of ecosystem, sociocultural and economic services. But in the modern period, there is a decrease in the share of common oak natural forests in the forest reserves of European countries and various manifestations of their degradation. Floodplain forests form a particular value among natural oakwoods. They’re not only play an important role in the formation of vegetation and biogeocenotic cover, but also have a significant positive environment-transforming effect on soil-hydrological and mesoclimatic conditions. That helps to regulate the hydrological regime of river floods. An analysis of the current state of the tree-shrub vegetation of conditional reference linden-ash oakwoods of the central floodplain of the Samara River was conducted. They are a complex of forest vegetation component of Prysamary Dniprovskyi, the territory of which is reserved for the creation of a national nature park. The forest valuation indicators of stands of the main forest-forming tree species have been determined. According to the obtained data, the species composition of tree-shrub vegetation and the type of stand correspond to typical fresh central floodplain linden-ash forests. An increase in the share of participation in the tree stand of Acer campestre and a decrease of Tilia cordata are characteristic. Quercus robur and Fraxinus excelsior take a leading part in the formation of stocks of stem wood. It is determined that in the natural linden-ash oak centropopulation Fraxinus excelsior, Acer platanoides, Acer campestre, Ulmus laevis, Tilia cordata, Ulmus glabra, Pyrus communis, Ulmus minor belong to the normal type and are stable and capable of self-maintenance. The most active self-regeneration is recorded in Acer campestre. The population of Quercus robur is characterized as regressive with signs of disruption of natural regeneration processes and the absence of healthy undergrowth. Fraxinus excelsior, Acer platanoides, Ulmus laevis, Pyrus communis are distinguished by the highest indicators of vitality ((Ln) and according to the index of relative vitality their tree stands belong to the “healthy” categoty. The tree stand of Quercus robur belongs to the “weakend” category. Deterioration of the vitality of Quercus robur tree stands and disruption of its self-regeneration processes can potentially lead to a decrease in the edifying role of oak in fresh linden-ash forets of the valley complex of the Samara River. Also, it can lead to a transformation of their type of wood composition and a decrease in productivity. Major of environmental significance of the forest vegetation of this area requires systematic comprehensive monitoring studies to update current data on the state of unique natural oakwoods. The presented results are a continuation of the monitoring studies of natural reference central floodplain linden-ash forests and can become the basis for the development of differentiated methods of their preservation and restoration.

Patterns and drivers of evapotranspiration in South American wetlands

Evapotranspiration (ET) is a key process linking surface and atmospheric energy budgets, yet its drivers and patterns across wetlandscapes are poorly understood worldwide. Here we assess the ET dynamics in 12 wetland complexes across South America, revealing major differences under temperate, tropical, and equatorial climates. While net radiation is a dominant driver of ET seasonality in most environments, flooding also contributes strongly to ET in tropical and equatorial wetlands, especially in meeting the evaporative demand. Moreover, significant water losses through wetlands and ET differences between wetlands and uplands occur in temperate, more water-limited environments and in highly flooded areas such as the Pantanal, where slow river flood propagation drives the ET dynamics. Finally, floodplain forests produce the greatest ET in all environments except the Amazon River floodplains, where upland forests sustain high rates year round. Our findings highlight the unique hydrological functioning and ecosystem services provided by wetlands on a continental scale.

Historical sampling error: A neglected factor in long-term biodiversity change research

Long-term time series are increasingly used to assess the effects of global change on plant community diversity and to guide management of target plant communities. However, historical biodiversity data may contain neglected sources of error that can have a significant impact on the results and their interpretation. In our study, we focus on historical sampling error, a source of potential bias in long-term biodiversity assessments that has not been systematically addressed. We resampled two historical datasets of a different origin in the floodplain forests of the Czech Republic, with 534 vegetation plots originally sampled in the 1950s and 1960s. We compared temporal trends in alpha diversity and Ellenberg indicator values (EIVs) between the two parallel surveys. To assess compositional differences, we compared temporal changes in species frequencies. Alpha diversity increased by 9.3 % in one resurvey, but decreased by an average of 30.8 % in the second resurvey. The distribution of EIVs for plots also differed, indicating that each resurvey covered a different part of the environmental gradient. We conclude that preferential historical sampling of the vegetation-environment continuum and species omission may have contributed to the differences in biodiversity and environmental change between the datasets. Our study shows that historical sampling error can have a significant impact on assessments of long-term biodiversity trends. We recommend that historical reference datasets should be critically assessed for potential sources of error in assessments of environmental change and management objectives.