Willow Communities Research Articles

Willow communities at technogenic habitats in the middle-taiga subzone of north-east of the European part of Russia

The paper highlights the diversity of willow communities at technogenic habitats of the middle taiga subzone of north-east of the European part of Russia. Willow communities at technogenic habitats normally develop at places with excessive soil moisture content. At places with optimal soil moisture content, they are found in relatively rich loams. Four new associations are described. They are mesophytic willow communities in middle loamy, as well as residual carbonate soils – Calamagrostio arundinaceae–Salicetum capreae, forest communities surrounding them –Calamagrostio arundinaceae–Piceetum obovatae, willow communities in excessively moist meso- and oligotrophic acid soils – Polytricho communis–Salicetum phylicifoliae, willow communities in meso- and eutrophic waterlogged soils confined to groundwater outlets – Drepanoclado adunci–Salicetum myrsinifoliae. For the latter association, 3 new subassociations are described (typicum, bryetosum pseudotriquetri, philonotietosum fontanae). Mesophytic willow communities at anthropogenically disturbed territories belong to the new alliance Betulo pubescentis–Salicion capreae. Willow communities at technogenic habitats with excessive soil moisture content are described within the alliance Alno incanae–Salicion pentandrae Kielland-Lund 1981. The communities dominated with willows at technogenic habitats mainly include early-succession species. The floristic composition of communities largely depends on the particular soil type. Comparing the species composition of willow communities and forest communities surrounding them, we diagnose certain signs of restoration even at the first succession stages. For example, the willow communities include species being typical of syntaxa of forest ecosystems at advanced successional stages.

Impacts of an extreme flood event on the riparian vegetation of a monsoonal cobble‐bed stream in southern Korea: A multiscale fluvial biogeomorphic framework

AbstractWith climate change increasing the magnitude and frequency of extreme precipitation events, there is a growing demand for investigations on the impacts of extreme flooding on the hydrological characteristics and vegetation of rivers, particularly in monsoonal areas. In this study, we examined multiscale relationships between hydrology, vegetation, and geomorphology after a record‐breaking flood event along the Seomjin River of South Korea in the summer of 2020. We conducted numerical modeling at the broad scale to identify the flow characteristics (e.g., depth and shear stress) of the flood event. A field survey was performed to investigate the impact of the flood on individual plants at the fine scale. The results showed widespread devastation of all vegetation types, from reed and willow communities to large, late‐successional trees taller than 10 m, which typically survive under ordinary flooding conditions. A higher threshold of shear stress was estimated for these trees (124 N m−2) than for willow (120 N m−2) and reed plants (26 N m−2), indicating that a greater level of stress is required to cause vegetation damage as ecological succession progresses. In the presence of vegetation, the average water depth increased by 9%–23% compared to the absence of vegetation. Many rivers in northeast Asia have undergone substantial vegetation expansion and succession due to the infrequency of extreme flood events. Our findings indicate that dense communities of large plants in these systems can raise the maximum water levels of flood events, thereby increasing the future flood risk to surrounding areas utilized for agriculture, transportation, industry, and housing.

Can grazing by elk and bison stimulate herbaceous plant productivity in semiarid ecosystems?

AbstractPlant communities in rangeland ecosystems vary widely in the degree to which they can compensate for losses to herbivores. Ecosystem‐level factors have been proposed to affect this compensatory capacity, including timing and intensity of grazing, and availability of soil moisture and nutrients. Arid ecosystems are particularly challenging to predict because of their high degree of temporal variability in moisture inputs. We used a replicated herbivore exclusion experiment to evaluate herbaceous plant responses to grazing by large ungulates to test current theory and identify constraints on plant compensation in a dryland ecosystem. We measured nitrogen (N) yield and herbaceous production in three plant communities: meadows, willow‐associated herbaceous communities, and riparian communities. We implemented grazing exclusion treatments from 2005 to 2008 in areas with elk and bison and areas with only elk. Grazing by large ungulates increased herbaceous production and N yield in herbaceous riparian communities. In willow communities, herbaceous plants displayed equal compensation in response to grazing in total aboveground production and N yield. Our results support the idea that plant compensation in this semiarid system is contingent on soil moisture availability, wherein the most productive sites (that received substantial moisture inputs from subsurface flow) exhibited overcompensation. Although the herbaceous riparian communities we studied are isolated patches of productive grassland in an otherwise shrub‐dominated and minimally productive semiarid landscape, grazing by a combination of bison and elk removed only 44%–53% of aboveground net primary productivity (ANPP) during the growing season, and 25%–38% of production over winter. Consumption by ungulates was a positive linear function of herbaceous production, similar to reported patterns from other temperate and tropical grazing ecosystems. The slope of this relationship was affected by the analytical method used to calculate ANPP and consumption rates, but, regardless of the method, was lower or similar to reported slopes for other intensively grazed systems (Yellowstone, Serengeti, Laikipia) that have sustained high ungulate densities for decades to centuries. Given that the vegetation communities exhibited equal or overcompensation in terms of total herbaceous ANPP in both years, elk and bison population levels during our study period did not appear to occur at densities leading to degradation of herbaceous communities.

Problems of biodiversity conservation of birch groves of the steppe Ural zone

An assessment of the taxonomic, structural, and functional biodiversity of birch groves of the steppe Ural zone which are unique phytocenoses that determine the structure of forest cover in areas with a regular lack of forest cover, is presented. Such communities play an important role in maintaining the ecological balance of the natural environment, namely in preserving biological and landscape diversity due to the formation of communities in contrasting physiographic conditions. We used the classical standard approaches of geobotany and the original methods of phytoindication of ecotopes, and the analysis of the aggregate parameters of the environment of ecocenoelements on the scales of the optimum of H. Ellenberg. The ecosystem function of biodiversity conservation is shown due to the formation of microsites: birch grove, feather grass steppe, willow community, petrophyte-steppe associations, at the contact points of which ecotone zones appear, differing due to the differentiation of physiographic conditions of great variety and sustainability of natural complexes. The necessity of preserving the complex of birch beam forests with a special aesthetic, scientific and cultural value for the conservation of biodiversity is shown.

Suppression of alien plant <i>Amorpha fruticosa</i> communities and transition test to native willow communities on the shoreline in the Miharu dam reservoir.

Suppression of alien plant <i>Amorpha fruticosa</i> communities and transition test to native willow communities on the shoreline in the Miharu dam reservoir.

Сообщества с кустарниковыми ивами в подзоне типичных тундр восточноевропейского сектора Арктики

Сообщества с кустарниковыми ивами в подзоне типичных тундр восточноевропейского сектора Арктики

Willow communities, optimal absorption of carbon dioxide from the atmosphere

High biological productivity of willow communities contributes to the effective performance of carbon dioxide absorption in photosynthesis. In natural communities, shrub willows hectareve a better effect on carbon dioxide balance: the amount of absorbed gas significantly exceeds its emission. Deciduous willows are able to fulfill the same condition, but only when grown in plantations. For the effective absorption of carbon dioxide, willow communities should meet the following parameters depending on the soil conditions. A one-year phytomass growth of axial shoots (in terms of absolutely dry matter) should be more thectaren 3.11 tons⋅hectare−1⋅year−1 on rich soils. This condition is fully met by the Salix dasyclados and S. viminalis communities. When growing on poor soils, annual phytomass growth of axial shoots of more thectaren 0.93 tons⋅hectare−1⋅year−1 is sufficient, which is noted in the communities of S. purpurea. The annual increase in phytomass of axial shoots should be more 2.48 tons⋅hectare−1⋅year−1 when growing on swampy soils. S. dasyclados and S. viminalis are the most suitable for plantation cultivation. These willow species perform the raw material function in the most effective way and, along with this, absorb carbon dioxide from the atmosphere in the greatest amount.

Originalities of Willow of Salix atrocinerea Brot. in Mediterranean Europe

Willow communities (genus Salix) occurring in Mediterranean Europe are presented, showing, through statistical treatment with multivariate cluster analysis, the separation of the different plant communities and their sintaxonomic affiliation. Six willow communities have been identified, whose formations include a set of plants with high heritage value. We highlight plants with legal protection status (Annex IV and II of the Habitats Directive-92/43/EEC), endemic, rare, and endangered species such as Salix salviifolia subsp. australis, Cheirolophus uliginosus, Euphorbia uliginosa and Leuzea longifolia. Therefore, two new willow communities are proposed for the southwest of the Iberian Peninsula. The first dominated by Salix atrocinerea, Frangulo baticae-Salicetum atrocinereae ass. nova of ribatagan distribution, under acid substrates, thermomediterranean to lower mesomediterranean, dry to sub-humid. The second, dominated by the endemic Salix salviifolia subsp. australis, Clematis flammulae-Salicetum australis distributed in the Algarve, developing on neutral-basic substrates, exclusively thermomediterranous, dry to sub-humid. In both cases, there are presented on their own floristic serial, ecology, and substitution steps. A new hygrophytic meadows was also identified dominated by Molinia caerulea subsp. arundinaceae, Cheirolopho uliginosii-Molinietum arundinaceae ass. new hoc loco, which lives on substrates rich in organic matter, exclusive to the Ribatagano Sector. Through the deepening of knowledge about the composition and dynamics of riparian vegetation, it is possible to adapt management methods to sustain and protect these important edafo-hygrophilic systems in the Mediterranean.

Functional traits of individual varieties as determinants of growth and nitrogen use patterns in mixed stands of willow (Salix spp.)

Short rotation plantations of willows (Salix spp.) have high biomass production potential in many parts of the world, and may frequently support ecosystem services related to nutrient cycling. A plantation management enhancing favorable environmental impacts that are conducive to maintaining ecosystem services is a main challenge in establishing sustainable biomass production systems. There is evidence supporting the hypothesis that biomass production and nutrient cycling can be increased by supporting ecosystem niche differentiation (complementarity) through enhancing the number of plant species or varieties grown in the stand. However, the specific trait values of the individual components (e.g., varieties) in a mixed community could also be more important than the community diversity per se. We assessed, at community level, the plant trait profiles related to growth and nitrogen (N) use for four different Salix varieties that were taxonomically distinct at species or genotype level (‘Björn’, ‘Jorr’, ‘Loden’, ‘Tora’) and field-grown in unfertilized plots of pure and mixed communities during one cutting cycle in Central Sweden. The aims were to use elements of functional growth analysis for exploring the mechanistic relationships between various traits related to growth and N use at stand level in our pure and mixed willow communities; and to address two hypotheses related to (i) the effect of diversity level on above-ground traits linked to growth, N uptake efficiency, N productivity and N conservation; and (ii) the influence of individual variety identities on the growth and N use traits observed in a mixture. Diversity level had no significant effect on the traits assessed here, and we thus found no evidence in support of our hypothesis that traits linked to growth, N uptake and use are significantly affected by the diversity level per se. In most but not all cases, the admixing effects on trait values were explained by the effects of the individual variety characteristics assessed in monocultures in combination with their relative share in the respective mixtures. The absence or presence of individual varieties strongly affected community-averaged (stand level) trait values. Therefore, the design of desirable variety mixtures is suggested that combine, for example, the high nutrient conversion efficiency that certain varieties achieve in mixed stands with the specific nutrient acquisition characteristics of other varieties.

Phytosociology, Distribution and Ecology of a Willow Community with False Tamarisk from the Lotru Valley (Romanian Carpathians)

The overall objective of this research was to contribute to a better knowledge of the phytosociology, ecology and distribution of the plant community formed by Myricaria germanica (false tamarisk) and the willow species Salix purpurea. This plant community has an important role in reducing the speed and strength of the water flow during floods. The description was based on cover‐abundance data for the faithful, dominant, characteristic and companion species of this plant community. A predominance of Myricaria germanica was observed when analysing the phytocoenoses, as the species finds in this area favourable ecological conditions for an abundant development. Salix purpurea presents a small abundance-dominance or in some phytocoenoses may even lack. The field research also revealed the excessive development of the species Calamagrostis pseudophragmites in some areas, related mostly with the effect of human activities. The anthropogenic disorders have induced modifications in the floristic physiognomy and compositions of the phytocoenoses, favouring also the invasion of opportunistic species such as Ambrosia artemisiifolia, Impatiens glandulifera, Phytolacca amearicana, Amorpha fruticosa, Erigeron annuus, which continuously extend in the studied territory. As Myricaria germanica and Salix purpurea phytocoenoses suffer a great decline throughout Europe, the habitat built by these species was declared of interest and was included in the Habitats Directive.
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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Carbon deposition by oak forests and willow communities

The peculiarities of carbon deposition in stands of oak quiver (Quercus robur L.), as well as in communities of shrub and tree life forms (Salix cinerea L., S. triandra L., S. viminalis L., S. purpurea L., S. fragilis L., S. alba L.). In the oak groves, the largest deposition of carbon is recorded in the fresh pine forest of Shipov, a forest of a late-blossoming species of oak tree, of natural origin at the age of 181 - 386.3 tons·ha-1. In forest oak cultures, the total mass of carbon concentrated in the tree stage has increased from 15.28 to 121.70 tons·ha-1 over the period from 19 to 76 years. High biological productivity of willow communities promotes effective performance of carbon-depositing function. The maximum amount of deposited carbon (31.7 tons·ha-1 for a 5-year life span) is noted in the communities of S. viminalis of sprouts originating in the shrub biomorph. Of all the studied biological species, the maximum phytomass increment is greatest, and accordingly the largest amount of carbon in the growth (5.62 tons·ha-1 year-1) occurs in S. viminalis when it grows in shrubby form.

The Willow Community Members' Exhibition, 31 August 2017

The Willow Community Members' Exhibition, 31 August 2017Catalogue

The Willow Community Creative Writing Fun, 5 February 2018

The Willow Community Creative Writing Fun, 5 February 2018Workshop catalogue

Impacts of recreation management practices in a subalpine wetland system dominated by the willow plant, Salix planifolia

Wetland habitat in the subalpine Rocky Mountains is an area of high biodiversity and includes many species of willow. These willow-dominated communities are often used for both summer and winter recreation. The maintenance of winter recreation trails has the potential to disturb wetland vegetation and compromise the long-term persistence of the wetland. In Breckenridge, Colorado, willow plants are clipped in October to a uniform height to prevent stems from protruding through the snow onto the ski trails, and large grooming tractors compact the snow on the trails. Our objective was to investigate the impact of winter recreation trail maintenance on growth and reproductive output of Salix planifolia (common names: planeleaf or diamondleaf willow) and to determine impacts on community diversity in a willow-dominated wetland system. Catkin production, plant height, and branch elongation were evaluated in meter-squared quadrats within paired belt transects both inside and outside a ski trail during the growing seasons of 2008 and 2009. In addition, percent cover of total vegetation was estimated for each species to calculate species richness and diversity. We found that maintenance of winter trails reduced catkin production and limited willow growth. Additionally, winter trail maintenance may have promoted the introduction of invasive species within the willow community. The activities associated with winter trail maintenance could interfere with the long-term persistence of the willow community adjacent to ski trails and should be considered when planning new trails in or along a wetland ecosystem.

Phytosociological analysis of montanesubalpine dwarf willow shrub communities in the Julian Alps and on the Trnovski gozd plateau (NW and W Slovenia)

AbstractBy means of a phytosociological analysis of 72 relevés of montane-subalpine shrub communities with dominating Rhododendron hirsutum, Salix waldsteiniana, S. glabra and S. appendiculata from the Julian Alps and the the Trnovski Gozd Plateau and by comparing them with similar communities elsewhere in the Alps and the Dinaric Alps we described a new association Laserpitio peucedanoidis-Salicetum waldsteinianae, a new subassociation Rhododendretum hirsuti vaccinietosum myrtilli, two new subassociations of the association Dryado-Rhodothamnetum chamaecisti that had recently been described in the Dolomites (-caricetosum firmae, -salicetosum waldsteinianae), as well as a new association Heliospermo pusillae-Rhododendretum hirsuti. We classified the glabrous willow community in the study area into a new association Homogyno sylvestris- Salicetum glabrae and proposed a new name - Rhododendro hirsuti-Salicetum appendiculatae for the large-leaved willow community, which we subdivided into two geographical variants: var. geogr. Paederota lutea (Julian Alps, Trnovski Gozd Plateau) and var. geogr. Hypericum grisebachii (Liburnian Karst).

Physcia alnophila (Vain.) Loht. et al. на Дальнем Востоке России

In this paper we present data on the distribution in the Russian Far East and surrounding areas (Trans-Baikal Territory and Japan) of Physcia alnophila (Vain.) Loht. et al. (Physciaceae), for the first time found in the South of the Russian Far East. Area of distribution of P. alnophila is circumpolar, associated with the boreal zone; the species is limited in their distribution by northern territories, in the south (the Khabarovsk Territory, the Jewish Autonomous Region, Sakhalin region) P. alnophila is rare and not abundant. P. alnophila grows on different broad-leaved and small-leaved tree and of conifer only on Picea. In the study of 18 Japanese (TNS) samples only Physcia aipolia was identified, although the nearest finding of Physcia alnophila was made in the southern part of Sakhalin Island. The northernmost location of the species is on the Chukotka Peninsula in the northeastern part in Willow community, on the bark of deciduous (Alnus and Betula) tree. We give the anatomic-morphological description of the species based on the study of the samples collected (total 34). Anatomical and morphological characteristics of the samples are almost entirely consistent with those given by R. Moberg (1977): ascospores are slightly wider and shorter in extreme values, in average values coincide completely. The average length of the spores in the studied samples of P. alnophila was 20 μm, while the samples of P. aipolia – 24 μm (N = 35). We have also noted that P. alnophila samples from Yakutia apothecia are somewhat larger, up to 2.5 mm in diameter, 0.5–1 mm more than indicated in previous works.

Hydro-hygrophilous vegetation diversity and distribution patterns in riverine wetlands in an agricultural landscape: a case study from the Oglio River (Po Plain, Northern Italy)

In the European plains, up to eighty percent of riverine wetlands have been lost due to alteration of hydrological regime and catchment exploitation. This condition is expected to be further negatively exacerbated by climate change. To better understand the observed change in distribution patterns of hydro-hygrophilous vegetation in temperate and Mediterranean floodplains, a vegetation survey was conducted within the lower Oglio River reach in Northern Italy. This river is a mid-size, altered and nutrient-rich left tributary of the Po River. During the 2008 growing season, a total of 60 marginal aquatic habitats were investigated. Overall, 37 vegetation communities were detected, showing a clear predominance of hygrophilous herbaceous plant communities both in terms of representativeness (55.1%) and diversity (54.1%) with respect to woody (22.9% and 10.8%, respectively), and obligate aquatic vegetation (22.0% and 35.1%, respectively). Our main findings were (1) the widespread presence of highly opportunistic, non-native and invasive hygrophilous plant communities (largely dominated by Amorpha fruticosa, Phragmites australis s.l., Amaranthus spp., Bidens spp., and Cyperus spp.), and (2) the limited distribution of hydrophyte vegetation usually dominated by pleustophytes (e.g., Spirodela polyrhiza and Lemna spp.). The present study confirms the dominance of secondary plant communities characterized by the widespread presence of alien species in lowland over-exploited riverscapes, coupled with a low local representativeness of native willow (Salix alba, S. cinerea) communities and anchored macrophyte (batrachid, ceratophyllid, elodeid, myriophyllid) meadows. Total vegetation diversity is consistent with previous studies in similar ecological contexts; on the other hand, at the site scale, the diversity values were extremely low. This is especially true for the aquatic vegetation, and can be related to the high water turbidity and chlorophyll-a concentrations that prevent the establishment and colonization of submerged and rooted hydrophytes. Consequently, we stress the need for metabolic and biogeochemical indicators to assess the actual trophic status of lowland wetlands in order to clarify their potential to be restored.

Interactions of sapsuckers andCytosporacanker can facilitate decline of riparian willows

Drought has caused large-scale plant mortality in ecosystems around the globe. Most diebacks have affected upland forest species. In the past two decades, a large-scale decline of riparian willows (Salix L.) has occurred in Rocky Mountain National Park, Colorado. We examined whether climatic or biotic factors drive and maintain the willow community decline. We compared annual growth and dieback of willows inside and outside of 14-year-old ungulate exclosures and measured groundwater depth and predawn xylem pressures of stems as indicators of drought stress. We also performed an aerial photo analysis to determine the temporal dynamics of the decline. Aerial photo analysis indicated willow decline occurred between 2001 and 2005 and was best explained by an increase in moose population and a decrease in peak stream flows. A new mechanism for willow stem dieback was identified, initiated by red-naped sapsucker wounding willow bark. Wounds became infected with fungus that girdled the stem. DNA analyses confirmed Valsa sordida (Cytospora chrysosperma) as the lethal fungus. Captured sapsuckers had V. sordida spores on feet and beaks identifying them as one possible vector of spread. Predawn xylem pressure potentials remained high through the growing season on all study willows regardless of depth to ground water. Our results indicate that additional mechanisms may be involved in tall willow decline.

The role of riparian willows in phosphorus accumulation and PCB control for lotic water quality improvement

A better understanding of the role played by willow communities in the control of phosphorus levels in riparian zones is necessary for sustainable water management and water quality improvement. This study examines the role of communities of Salicetum triandro-viminalis in the reduction of phosphorus in river water and quantifies the phosphorus retained in the willow biomass. Significant decreases were observed in the concentrations of suspended particulate matter (SPM, 41%), soluble reactive phosphorus (SRP, 54%) and total phosphorus (TP, 36%) along a section of the Pilica River, Central Poland, nearly 40km long during the period 2005–2007. Moreover, differences in PCB concentration were observed in sediments taken from the upstream and downstream parts of the same river stretch, with a 49% decrease of PCB TEQ concentration. In this river section, natural willow communities covered an area of approximately 30ha. The accumulation of phosphorus (P) in the total biomass amounted to approximately 431kg, a mean of 14.44kgPha−1 for willow patches up to 3 years old. The paper identifies the willow riparian zones with the highest biomass concentrations of phosphorus, which are most suitable for management and seasonal clear-cutting. This could be helpful in limiting eutrophication and controlling toxic algal blooms in the Sulejów Reservoir located downstream.

Stream hydrology limits recovery of riparian ecosystems after wolf reintroduction

Efforts to restore ecosystems often focus on reintroducing apex predators to re-establish coevolved relationships among predators, herbivores and plants. The preponderance of evidence for indirect effects of predators on terrestrial plant communities comes from ecosystems where predators have been removed. Far less is known about the consequences of their restoration. The effects of removal and restoration are unlikely to be symmetrical because removing predators can create feedbacks that reinforce the effects of predator loss. Observational studies have suggested that the reintroduction of wolves to Yellowstone National Park initiated dramatic restoration of riparian ecosystems by releasing willows from excessive browsing by elk. Here, we present results from a decade-long experiment in Yellowstone showing that moderating browsing alone was not sufficient to restore riparian zones along small streams. Instead, restoration of willow communities depended on removing browsing and restoring hydrological conditions that prevailed before the removal of wolves. The 70-year absence of predators from the ecosystem changed the disturbance regime in a way that was not reversed by predator reintroduction. We conclude that predator restoration may not quickly repair effects of predator removal in ecosystems.