Alder Swamp Research Articles

Changes in bryophyte communities and their functional traits along black alder swamp forest chronosequence

Changes in bryophyte communities and their functional traits along black alder swamp forest chronosequence

Effect of vegetation cover and soil moisture on water repellency persistence of drained peat soils

AbstractPeatlands play an essential role in the environment and their conservation requires knowledge of water-related processes. Their hydrophobicity is an important factor influencing the flow of water in soils. Drainage of fens and adapting them for agricultural production have contributed to the degradation of peat soils. The main goal of this study was to evaluate the effect of vegetation cover (meadows, alder swamp and birch forest) of drained peat soils on the persistence of their water repellency as a function of their moisture content. Soil samples (Rheic Fibric Histosol and Rheic Murshic Hemic Histosol) were collected from four sites in the Biebrza Wetlands (Poland). The sites include extensive meadows, intensive meadows, alder swamp forest, and secondary birch forest. The study used the Water Drop Penetration Time (WDPT) to assess the persistence of soil water repellency during the drying of soil samples in laboratory conditions. The study proposed a three-straight lines model to describe the relationship between WDPT and soil moisture content. Results revealed that the peat soils in intensive meadows showed the highest WDPT, followed by the secondary birch and alder swamp forest. and then by semi-natural meadows, which has the lowest WDPT.

Synergies and trade-offs among ecosystems functions and services for three types of lake-edge wetlands

Wetlands are the world’s most important providers of ecosystem functions and services (EFS) and the most threatened ecosystems. Systematic conservation planning strategies are urgently needed to identify efficient strategies that optimize EFS provisioning in wetlands. Evaluating synergies and trade-offs among EFS indicators provides an ideal framework, as they highlight the challenges faced by conservationists. However, associations between indicators often vary across region, scale, and ecosystem type. In this study, we compared the provisioning of eight EFS of three types of wetlands to evaluate the influence of indicator choice and aggregation on synergies and trade–offs. We quantified 25 EFS indicators in 37 lake-edge wetlands consisting of 12 peatlands, 8 alder swamps, and 17 ash swamps. We analyzed the synergies and trade-offs among wetland types and among EFS indicators, as well as the general EFS provisioning patterns of each type using cosine similarities and multivariate analysis. We showed that wetland type strongly influences the strength and direction of associations, with peatlands and ash swamps showing opposing patterns. While some EFS categories are less sensitive to indicator choice and aggregation, others, such as biodiversity, show important trade-offs. Our results revealed that synergies and trade-offs are strongly influenced by indicator choice and that protecting a diversity of wetland types is necessary to support multiple EFS categories.

Spatio-Temporal Variability of Methane Fluxes in Boreo-Nemoral Alder Swamp (European Russia)

In 1995–1998 and 2013–2016, we measured methane fluxes (1Q-median-3Q, mgC m−2 h−1) in the Petushikha black alder swamp of the boreo-nemoral zone of European Russia. At microelevations (EL sites), flat surfaces (FL), microdepressions (DEP), and water surfaces of streams and channels (STR) sites, the fluxes comprised 0.01–0.03–0.09, 0.02–0.06–0.19, 0.04–0.14–0.43, and 0.10–0.21–0.44, respectively. The biggest uncertainty of methane fluxes was caused by seasonal variability (the level of relative variability of fluxes is a nonparametric analogue of the coefficient of variation) which comprised 144%, then by spatial variability—105%, and the smallest by interannual variability—75%. Both spatial and temporal variability of methane fluxes at different elements of the microrelief is heterogeneous: the most variable are communities that are “unstable” in terms of hydrological conditions, such as FL and DEP, and the least variable are the most drained EL and the most moistened STR (“stable” in terms of hydrological conditions). The obtained data on the fluxes and their spatial and temporal variability are consistent with the literature data and can be used to optimize the process of planning studies of the methane budget of “sporadic methane sources”, such as waterlogged forests. This is especially relevant for an adequate assessment of the role of methane fluxes in the formation of the waterlogged forests carbon budget and a changing climate.

Late Holocene Vegetation and Environmental Changes of Coastal Lowlands in Northern Iran: Possible Role of Climate, Human Impact and Caspian Sea Level Fluctuations

Coastal forests and wetlands play an important role in supporting biodiversity, protecting the hinterlands and shorelines from erosion and also contributing to carbon sequestration and freshwater storage. To reconstruct late Holocene vegetation and environmental dynamics in the coastal lowlands of northern Iran and to detect the possible role of climate, human and Caspian Sea level fluctuation on coastal ecosystems, multi-proxy analysis was applied on the sediment cores from the inland Eynak (EYK) lagoon and near coast Bibi Heybat (BBH) alder swamp. Results shows that in the last 170 years, strong reduction of alder forest occurred around Eynak lagoon, while an expansion occurred in the coastal area in the last 100 years. This indicates that human impact shifted from the near coast to elevated inland, which might be due to the raised water level from the Caspian Sea and the coastal area of BBH region was flooded by brackish water from the Caspian Sea, and was not so suitable for agriculture anymore. This study indicate that alder swamp extent is different between coastal and inland sites, suggesting that further studies of multiple records across the region are needed. Moreover, this study helps to distangle human impacts from wetland processes and thus will be an important contribution to effective climate mitigation and conservation strategies. This multi-proxy study presents important palynological records, which helps to understand past and future impacts of various drivers, such as climate, human impact and sea level changes on wetland ecosystems both regionally and globally.

О флоре федерального природного заказника «Олонецкий» (Республика Карелия)

Olonetsky Nature Reserve (Zakaznik), located in Southern Karelia, was established in 1986 in an area of 27000 hectares. Surveys have detected 447 species of vascular plants, including 372 (83,2 %) native and 75 (16,8 %) alien ones. The shore dunes and sandy beaches of Lake Ladoga, as well as black alder swamps in depressions between ancient levees harbored the most distinctive flora. Festuca sabulosa, Hypopitys monotropa, Jovibarba globifera, Oenanthe aquatica, and Viola stagnina are red-listed in Karelia; seven more species are in need of monitoring. The spread of the aggressive invasive species Rosa rugosa is of particular concern.

Soil Respiration in Alder Swamp (Alnus glutinosa) in Southern Taiga of European Russia Depending on Microrelief

Swamp forests have been insufficiently studied yet in comparison with thoroughly examined carbon pools and greenhouse gas fluxes of peat bogs. This is primarily since the GHGs in swamp forests have huge spatial (due to the developed microrelief) and temporal variations (due to strong fluctuations in the groundwater level (GWL)). This significantly complicates their study, producing ambiguous results, especially in short-term field research. From June to October 2013–2016, we measured soil respiration (Rsoil) in an alder swamp using the static chamber method at five microsites: depression (DEP), flat surface (FL), elevations (EL), tussocks (TUS), and near-stem tussocks (STUS). We carried out a computer simulation of the total Rsoil for the season based on Rsoil measurements, monitoring of GWL, and soil temperature. In 2013–2016, the average Rsoil values (mgC m−2 h−1 ± σ) on DEP, FL, EL, TUS and STUS comprised 54 ± 50, 94 ± 72, 146 ± 89, 193 ± 96, and 326 ± 183, respectively, whereas the total Rsoil values for the season (tC ha−1 season−1 ± σ) comprised 2.0 ± 0.5, 3.5 ± 0.5, 5.3 ± 1.6, 5.4 ± 2.7, and 12.6 ± 3.2. According to the results of observations, GWL was at the level of several cm below the soil surface for most of the season. In 2014 and 2015, there were extra dry periods that led to a drop in GWL to a mark of 30–40 cm below the soil surface. Despite their short duration (2–3 weeks), these dry periods can lead to an increase in the total Rsoil for the season from 9 to 45% in the TUS–EL–STUS–FL–DEP sequence.

Anaerobic guilds responsible for mercury methylation in boreal wetlands of varied trophic status serving as either a methylmercury source or sink.

Wetlands are common sites of active Hg methylation by anaerobic microbes; however, the amount of methylmercury produced varies greatly, as Hg methylation is dependent upon both the availability of Hg and the composition and activity of the microbial community involved. In this study, we identified the major microbial guilds responsible for Hg methylation along a trophic gradient composed of two sites and three different types of wetlands: a bog-fen peatland gradient and a black alder swamp, serving as net sources and a sink for methylmercury respectively. Iron-reducing bacteria in the Geobacteraceae were important Hg methylators across all wetlands and seasons examined, as evidenced by abundant 16S rRNA and hgcA transcripts clustering with this family. Molybdate inhibited Hg methylation more efficiently in the peatlands than in the swamp, suggesting an increasing role of sulfate-reducing bacteria and/or related syntrophs in the methylation of Hg with decreasing trophic status. Sulfate addition failed to increase Hg methylation rates in the peatlands, suggesting that SRBs/syntrophs were instead likely metabolizing alternative substrates such as syntrophic fermentation of organic compounds with methanogens. These results highlight the interconnectivity of anaerobic metabolism and importance of community dynamics on the methylation of Hg in wetlands with different trophic status.

Floodplain forest vegetation in the northern part of the Western Carpathians

Floodplain forests, as diverse plant communities commonly related to riparian zones, host plant species with various ecological niches and origins. The phytosociological context of floodplain forests has been well described on national level in many European countries, however, there are still regions with relatively poorly known variability of their species composition and environmental drivers controlling their vegetation patterns. Vegetation sampling of floodplain forests using traditional European phytosociological approach along with the recording of environmental (climatic, edaphic, topographic) variables was carried out in the northern part of the Western Carpathians (Slovakia and Poland) in period of 2011–2016. We gathered dataset of 135 original phytosociological releves, which were classified using modified TWINSPAN algorithm. Five associations were distinguished: (i) meso-eutrophic black alder swamp forests (Carici acutiformis-Alnetum glutinosae), (ii) montane oligotrophic mixed spruce-alder forests on waterlogged sites (Piceo abietis-Alnetum glutinosae), (iii) riparian willow forests (Salicetum fragilis), (iv) meso-hygrophilous riparian alder forests (Stellario nemorum-Alnetum glutinosae) and (v) riparian grey alder forests (Alnetum incanae). Canonical Correspondence Analysis (CCA) with forward selection was used to show effect of environmental factors on species composition variation. The explained variance declined from marginal (13.9%) and conditional (8.6%) to pure effect (7.5%), with altitude (1.6%), total soil nitrogen content (1.6%) and soil pH (1.4%) being the most important predictors accounted for the highest variation in species compositional data.

Drained ash swamp (Veratro albi-Fraxinetum angustifoliae), a new association in the Nyírség, NE Hungary

This paper presents the phytosociological description of a drained swamp community, Veratro albi-Fraxinetum angustifoliae, so far found only in the Nyírség at Nyírábrány “Kis-kőrises”, “Mogyorósi-erdő”; Vámospércs “Jónásrész-Kőrises”; and Vámospércs “Jónásrész-Buzita”. The habitat of the community is transitional between that of alder swamps (Fraxino pannonicae-Alnetum glutinosae), and hardwood riparian forests (Fraxino pannonicae-Ulmetum). The community is characterised by high proportions of character species of Alnion glutinosae and Molinion coerulei as well as Quercetea pubescentis-petraeae s. l. whereas character species of the order Fagetalia are almost completely absent. It hosts several rare, often threatened species, such as Angelica palustris, Ophioglossum vulgatum, Trollius europaeus and Veratrum album.

Effects of agricultural lands on habitat selection and breeding success of American kestrels in a boreal context

Sudden changes in habitat quality during the breeding season may mislead individuals when selecting their nesting site and result in population declines. In such cases, even semi-natural and extensive agricultural lands may become ecological traps. We examined how the availability of six open habitat types (i.e. agricultural lands, open forests, alder swamps, young forests, regeneration, and wetlands) could be affecting the habitat selection process, as well as the hatching and fledging successes of American kestrels (Falco sparverius). We hypothesized that natural open habitats are less disturbed by anthropogenic activities than extensive agricultural lands and thus represent higher quality habitats for kestrels. We also considered weather conditions during the breeding season as possible factors affecting hatching and fledging successes. We monitored 200 pairs of American kestrels during 11 years (2006–2016) within a network of 155 nest box stations and we characterized landscape composition metrics within 800 m radii from each nest box. We used generalized linear mixed models and multimodel inference to quantify the effects of landscape composition metrics on the probabilities of using nesting site, hatching success, and fledging success of American kestrels. We also tested the effects of weather conditions and clutch initiation date on hatching and fledging successes of kestrels. We found that the probability of nesting site use increased with the amount of agricultural lands. Hatching success decreased with the amount of agricultural lands, whereas the fledging success of kestrels did not vary with the amount of agricultural lands. Both the probabilities of hatching and of fledging increased with the area of young forests. There was no evidence of a weather effect on hatching success. However, the probability of fledging success increased with mean temperature during the raising period of nestlings. Although fledging success alone does not determine fitness or population dynamics, our results suggest that kestrels nesting in this region at the northern limit of their range may be caught in an ecological trap by extensive agricultural lands. Indeed, kestrels were attracted by meadows when selecting nesting habitat, but the hatching and early nestling periods coincided with hay harvesting which could reduce the hunting success of breeding adults and suddenly alter food availability. Although the causes of recent kestrel declines remain unclear, our results suggest that harvesting practices, even those related to extensive perennial agriculture, may have a negative effect on the breeding success of the species compared to areas dominated by young forests.

Changes in Species Composition in Alder Swamp Forest Following Forest Dieback

It is generally hypothesized that forest dieback is a characteristic of alder swamp forests (alder carrs, Alnion glutinosae alliance). Different internal and external factors may trigger this process, including human disturbance, changes in river discharge, unusually severe and prolonged flooding, terminal age of an even-aged alder forest (ca. 100–150 years) and others. Although forest dieback in this type of forest may cause major changes in environmental conditions, the influence of this change on the floristic composition has not been well recognized. The study aimed to detect any possible changes in floristic variation in alder swamp forest following forest dieback. Vegetation plots in alder swamp forests affected by forest dieback were resurveyed 20 years after a previous study. PERMANOVA was used to test the significance of the compositional change and nonmetric multidimensional scaling (NMDS) with passively fitted means of the Ellenberg’s Indicator Values were used to interpret its ecological meaning. In addition, different structural and diversity indices were compared, including species richness, percentage cover of vegetation layers, Shannon and Simpson diversity and evenness. Finally, we analyzed changes in the frequency of vascular plant species using Chi square tests. We recorded clear and significant compositional changes following alder swamp forest dieback. This change was most related to the gradient of moisture, followed by the gradients of light and temperature. The analysis of the individual species showed that the species of hummocks declined, while the species of hollows increased. Moreover, the current communities are dominated by some hydrophytes that were not recorded 20 years ago. Forest dieback resulted in profound changes in the hydrological regime. The observed changes are consistent with a model of cyclic succession as proposed for alder swamps. In addition, we conclude that the natural forest dynamics have to be taken into consideration while interpreting the results of re-survey studies.

Mechanisms of Methyl Mercury Net Degradation in Alder Swamps: The Role of Methanogens and Abiotic Processes

Wetlands are common net producers of the neurotoxin monomethylmercury (MeHg) and are largely responsible for MeHg bioaccumulation in aquatic food-webs. However, not all wetlands net produce MeHg; notable exceptions are black alder (Alnus glutinosa) swamps, which net degrade MeHg. Here we report the mechanisms of MeHg demethylation in one such swamp (EHT), shown to be a sink for MeHg during four consecutive years. The potential demethylation rate constant (kd) in soil incubations was ∼3 times higher in the downstream (EHT-D: kd ∼ 0.14 d–1) as compared to the upstream part of the swamp (EHT-U: kd ∼ 0.05 d–1). This difference concurred with increased stream and soil pH, and a change in plant community composition. Electron acceptor and inhibitor addition experiments revealed that abiotic demethylation dominated at EHT-U while an additional and equally large contribution from biotic degradation was observed at EHT-D, explaining the increase in MeHg degradation. Biotic demethylation (EHT-D) was primarily due t...

A belső-somogyi homokvidék égerlápjainak cönológiai vizsgálata (Carici elongatae-Alnetum glutinosae W. Koch 1926)

The studied alder swamps are situated in SW Hungary on aeolian sand. Its canopy is dominated by Alnus glutinosa. Statistics of flora elements, life forms, phytosociological characters and social behaviour types are given. The surveyed stands are characterised by following specialists: Carex elongata, Hottonia palustris, Thelypteris palustris, Dryopteris carthusiana, D. dilatata, D. cristata, Urtica kioviensis, Ludwigia palustris, Leucobryum glaucum, Sphagnum palustre.

Continuum of floristic composition between two plant communities – Carici elongatae-Alnetum and Fraxino-Alnetum

Abstract One of the crucial debates in vegetation ecology is whether plant communities are discontinuous, distinguishable units or whether they change continuously. Phytosociology assumes discontinuity and its methodology requires subjective sampling during vegetation inventories. For that reason, some researchers argue that phytosociology artificially creates discontinuity among plant communities. Our aim was to assess the continuity between ash-alder riparian forest (Fraxino-Alnetum), and alder swamp forest (Carici elongatae-Alnetum), and to check whether discontinuity observed between these two plant associations is an effect of subjective sample plot choice. We conducted 57 phytosociological relevés within a regular grid covering potential sites of both plant communities. All relevés were arranged in order of decreasing relative cover of the diagnostic species for each plant association resulting in a gentle gradient, indicating a continuous transition from Fraxino-Alnetum to Carici elongatae-Alnetum. Similar results were obtained by detrended correspondence analysis. The proportion of species from the Querco-Fagetea class, typical to Fraxino-Alnetum, was decreasing with increasing proportion of species from the Alnetea glutinosae class, typical to Carici elongatae-Alnetum. This shift followed a gradient of ecological light-moisture indicator values. Our results confirmed continuous transition between two plant communities and led us to the conclusion that discontinuity resulted from the standard sampling protocol used in classical phytosociology. This protocol, however, is useful in searching for typological patterns, required for classification of plant communities, which is the main aim of phytosociology. Nevertheless, it does not provide full insight into the variability of vegetation and introduces uncertainty when trying to understand ecosystem dynamics. This uncertainty should be taken into account when phytosociological data are used for nature conservation recommendations and to draw conclusion about vegetation dynamics.

Do Multi-year Applications of Bacillus thuringiensis subsp. israelensis for Control of Mosquito Larvae Affect the Abundance of B. cereus Group Populations in Riparian Wetland Soils?

Bacillus thuringiensis subsp. israelensis (Bti) is a soil-borne bacterium affiliated to the Bacillus cereus group (Bcg) and has been used in biocontrol products against nematoceran larvae for several decades. However, knowledge is limited on whether long-term Bti application can affect the structure of indigenous communities of Bcg and the overall abundance of Bti. Using species- and group-specific quantitative PCR assays, we measured the Bcg- and Bti-abundances in riparian wetlands in the River Dalälven floodplains of central Sweden. On five occasions during one vegetative season, soil samples were collected in alder swamps and wet meadows which had been treated with Bti for mosquito larvae control during the preceding 11years, as well as in untreated control sites and well-drained forests in the same area. The average abundance of Bcg in alder swamps was around three times higher than in wet meadows. Across all sites and habitats, the Bti treatments had no effect on the Bcg-abundance, whereas the Bti-abundance was significantly higher in the treated than in the control sites. However, for individual sampling sites, abundances of Bti and Bcg were not correlated with the number of Bti applications, indicating that added Bti possibly influenced the total population of Bti in the short term but had only a limited effect in the longer term. The findings of this study increase the understanding of the ecology of Bti applications for mosquito control, which can facilitate environmental risk assessment in connection with approval of microbiological control agents.

Ramularia ajugae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Ramularia ajugae , a plant parasite, apparently obligately associated with its host plants, causing a leafspot disease, with records on living, dying and dead leaves. This species has been recorded with its host plants from deciduous woodland, mixed plantations, bare ground in alder swamps, on rocks by stream, in parkland, on moorland, and in fens and farmlard. Some information on its associated organisms and substrata, habitats, dispersal and transmission and conservation status is given, along with details of its geographical distribution (Africa (Kenya, South Africa)), North America (USA (Massachusetts, Ohio)), Asia (Armenia, Azerbaijan, China (Guangxi), Georgia, India (Himachal Pradesh), Australasia (Australia (New South Wales, Queensland), New Zealand), Europe (Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Montenegro, Netherlands, Norway, Poland, Romania, Russia (Kirov oblast, Lipetsk oblast), Serbia, Sweden, Switzerland, Ukraine, UK)) and hosts (including Ajuga spp.). No reports of negative economic impacts of this fungus have been found.

Ecological and human land-use indicator value of fungal spore morphotypes and assemblages

The value of non-pollen palynomorphs (NPPs) to complement reconstructions of past communities and environments has led to the identification of an increasing number of microfossil morphotypes. Unfortunately, limited knowledge about their specific ecological indicator values still restricts the interpretation of NPP accumulation rates or assemblage variations. Here, a comparison with classical palaeoecological proxies along a sedimentary sequence has been tested to improve the ecological indicator values of NPP morphotypes. Pollen, geochemical and NPP analyses performed on the same samples all along the Holocene sedimentary sequence of Lac de Moras (France) were compared using principal component analysis to identify statistical relationships and to establish correlations between all these parameters. Ecological indicator values were obtained for some morphotypes such as UG-1097 which is related to specific taxa (Corylus sp.), or Diporotheca rhizophila defined as an indicator of the local presence of alder swamp habitat. However, most of the NPP morphotypes can be combined in two opposite NPP assemblages reflecting the change from natural to managed ecosystems at the drainage basin scale and over the Holocene. It more specifically illustrates a change in the source of organic matter transferred to the lake system provided from the plant debris of woodland cover (litter) to organic matter from animal excreta (dung and manure).

Long-term vegetation dynamics and land-use history: Providing a baseline for conservation strategies in protected Alnus glutinosa swamp woodlands

Alnus glutinosa (alder) swamp woodlands are in danger of disappearing in Europe and, in Norway, several habitats with alder are threatened. Knowledge about the dynamics of alder swamp woodlands is crucial for the conservation and management of this vegetation. Our studied site, Rambjøra, in western Norway encompasses the Rambjøra Landscape Protected Area. We combined information from three sources—recent alder swamp woodland ecology, vegetation history, and agricultural history—to reveal the long-term vegetation dynamics of Rambjøra in relation to land-use. Dynamic changes in the predominance of forest or semi-natural grassland over 2800years, concurrent with varying anthropogenic disturbances are inferred. At the investigated site, alder swamp woodland developed after forest clearance and changes in the water balance. The abundance of alder swamp woodlands have varied through time, increasing with low-impact land-use and declining with intensified use or abandonment. The highest biodiversity is found in periods with grazing, hay mowing, and probably fodder and fire wood collection. This indicates that agricultural practices of moderate intensity (grazing and hay cutting) should be part of the future management in order to maintain the biodiversity and meet the objective of the protection of Rambjøra. The study demonstrates the advantages of combining vegetation surveys, pollen records, and land-use history to provide a long-term perspective on vegetation development, and in our case also as an aid when establishing conservation strategies. Our findings need to be considered in future conservation and restoration of ecosystems with alder swamp woodlands.

Égerlápok a Tengelici-homokvidéken (Carici elongatae-Alnetum glutinosae W. Koch 1926)

The study containsa phytosociological analysis of alder swamps found in the Tengelic sand Ridge, an expanse of mostly windblown sand in the westernmost part of the Great hungarian Plain, west of the Danube River. These swamps oc-cur in the depressions among sand dunes, where the ground is covered with water for most part of the year. The species composition is characterized by the dominance of alder (Alnus glutinosa) in the forest canopy with the sporadic occurrence of common birch (Betula pendula). The stands also host several rare herbaceous species, some of which are considered relics in the Great Plain, such as Carex paniculata, C. pseudocyperus, Cirsium palustre, Dryopteris carthusiana, D. dilatata, D. expansa, Listera ovata, Thelypteris palustris, Urtica kioviensis, and Veratrum album.