Grey Willow Research Articles

Plant‐sex‐biased tritrophic interactions on dioecious willow

Plant sex effects on herbivores are well studied, but little is known about these effects on predators and predator–herbivore dynamics. Here we take a holistic approach to study, simultaneously, plant sex effects on herbivore and predator preference and performance, as well as population densities and predation pressure in the field. For dioecious Salix cinerea (grey willow) we found that male plants represented higher host plant quality than females for an omnivorous predator (Anthocoris nemorum, common flower bug), while host plant quality for its herbivorous prey (Phratora vulgatissima, blue willow beetle) was not sex‐biased. The herbivore strongly preferred the host plant sex (female) that was suboptimal for the predator, which in turn followed its prey to female plants, leading to plant‐sex‐biased predation. These results provide new insight into the far‐reaching effects of plant sex on insect communities, and open up novel opportunities for improving biocontrol of the herbivore in Salix short rotation coppice.

Use of the silverleaf fungus Chondrostereum purpureum for biological control of stump-sprouting, riparian weedy tree species in New Zealand

Conventional willow control in wetland and riparian areas of New Zealand is undertaken using cut-stump and/or drill and injection application of glyphosate. The presence of herbicide residues in catchment water supplies has seen the investigation of non-chemical alternatives to poplar and willow control in Auckland water catchment areas. We have demonstrated, in glasshouse trials, the efficacy of an aqueous, gel-based formulation of Chondrostereum purpureum to control the regrowth of crack and grey willow (Salix fragilis and S. cinerea). Chondrostereum purpureum isolate ICMP 16392 (isolated from a Prunus sp.) produced the fastest biomass accumulation in liquid culture. Crack willow was significantly more susceptible to cut-stump infection by C. purpureum than grey willow in the glasshouse trial at the end of the 23-week period. Two different formulations were tested; at the end of the trial, there was no significant difference between them with respect to monthly biomass accumulation. Successful field applications of C. purpureum through cut and paste and drill and injection were confirmed by the presence of fruiting bodies on both treated species. Resprouting ability as measured by shoot number was significantly lower on C. purpureum inoculated stumps.

Растительность города Салавата (Республика Башкортостан). VI. Естественная лесная растительность

The studies of natural forest vegetation of Salavat town were made during 2008–2011. 31 relevés of forest communities within the natural boundaries of phytocenoses were done. Vegetation of Salavat town includes ruderal, grass (meadow, steppe, helophyte and water vegetation) and forest vegetation. Water, helophyte, synanthropic, natural and semi-natural grass vegetation of the town was discussed in previous articles (Golovanov et al, 2011 and others). This article is devoted to the syntaxonomy of natural forest vegetation of Salavat town. Syntaxonomy of natural forest vegetation of Salavat town includes 3 classes (Querco-Fagetea Br.-Bl. et Vlieger in Vlieger 1937, Salicetea purpureae Moor in 1958 and Alnetea glutinosae Br.-Bl. et Tx. ex. Westhoff et al., 1943), 3 orders (Fagetalia sylvaticae Pawłowski, Sokołowski et Wallisch 1928, Salicetalia purpureae Moor in 1958 and Salicetalia auritae Doing 1962), 4 alliances (Alnion incanae Pawłowski, Sokołowski et Wallisch 1928, Salicion albae Soó 1930, Salicion triandrae T. Müller et Görs 1958, Salicion cinereae T. Müller et Görs ex Passarge 1961), 4 associations (Alnetum incanae Lüdi 1921, Salici-Populetum (R. Tx. 1931 ) Meijer Drees 1936, Salicetum triandro-viminalis Lohmeyer 1952, Salicetum pentandra-cinereae Passarge 1961) and 5 variants (ass. Alnetum incanae — variant Galium aparine; ass. Salici-Populetum — variants Carex acuta, Bromopsis inermis, Carex praecox and Acer negundo). Plant communities of the class Querco-Fagetea combine the broadleaf and coniferous-deciduous mesophytic forests of the temperate zone of the western Palearctic (Ermakov, 2012). One variant Galium aparine of ass. Alnetum incanae was registered in Salavat town. This variant of the association was described from the urban areas. The presence of synanthropic species such as Acer negundo, Arctium lappa, Arctium tomentosum, Artemisia vulgaris, Chelidonium majus, Convolvulus arvensis, Galium aparine, Geum urbanum, Leonurus quinquelobatus and etc. is very typical. Plant associations represent forests with Padus avium, which are often found in the floodplain of the river Belaya on the rich short-time flooded soils. The class Salicetea purpureae includes both riverine floodplain forest and shrub communities (Yamalov et al., 2012). 2 associations (Salici-Populetum and Salicetum pentandra-cinereae) and 4 variants (Carex acuta, Bromopsis inermis, Carex praecox and Acer negundo) were distinguished. The plant communities of associations Salici-Populetum and Salicetum triandro-viminalis represent the floodplain willow-poplar forests and shrubby vegetation, which are commonly found in the Republic of Bashkortostan on the river banks and lakeshores. Typically the communities are found on the banks of the river Belaya within the town of Salavat (Khaziakhmetov et al., 1989). A distinctive feature of the communities is a presence of the North American invasive neophyte species Acer negundo. Naturalization of this species takes place on the floodplains of the Republic of Bashkortostan. The similar community was recorded in Bryansk region (Bulokhov, Kharin, 2008) and they were described as the association Aceri negundi–Salicetum albae Bulokhov et Charin 2008. Our communities are different due to the dominance of Populus nigra with insignificant role of Salix alba. Further data collection can help to describe the new unit of the ecology-floristic classification. The plant communities of the class Alnetea glutinosae combine the lowland eutrophic black alder swamps, birch swamp forests and thickets of willow shrubs on peaty soils (Ermakov, 2012). The association Salicetum pentandra-cinereae was described. The association represents of hygrophyte and mesohygrophyte communities with dominance of grey willow. These communities are found on the banks of fens and oxbows in abundant moisture conditions. They are rarely found on fen mires in Salavat town.

Beetle community responses to grey willow (Salix cinerea) invasion within three New Zealand wetlands

We investigated the effects of invasion by introduced grey willow (Salix cinerea) on beetle communities within four wetland vegetation types: native vegetation, native vegetation following grey willow removal, native vegetation undergoing grey willow invasion and dense grey willow-dominated vegetation. In total, 1505 beetles from 90 species were collected using modified Malaise traps. Native wetland vegetation had significantly lower beetle species richness than willow-dominated vegetation and was dominated by herbivores, whereas detritivores characterised willow-dominated vegetation. Beetle abundance was highest in the willow-dominated vegetation and mostly comprised detritivores. In contrast, beetle abundance was lowest in native wetland vegetation, but had even proportions of herbivores and detritivores. Native wetland vegetation had a high proportion of native beetles present. As grey willows invaded, introduced beetles became more common. The beetle community composition differed significantly between grey willow-dominated vegetation and native wetland vegetation. These compositional differences were mainly due to the increasing complexity of vegetation structure following grey willow invasion. The beetle communities within restored native wetland vegetation were most similar to those within the native wetland vegetation. From a conservation perspective, these results are encouraging and suggest that, although grey willows dramatically alter the composition of beetle communities present, these communities can be restored to a beetle fauna that is similar to those found within native wetland through the removal of the willows.

Temperate riverside forests without alder trees in the north-west of the Iberian Peninsula: ecology, phytosociological profile and interest for preservation policies

This paper describes three new riverside associations with no alder trees growing mainly along the middle and high altitude watercourses of the river basins located at the western end of the Cantabrian coast. Valeriano pyrenaicae-Fraxinetum excelsioris includes riverside mesoforests dominated by a combination of tree-like species (Fraxinus excelsior, Acer pseudoplatanus, Ulmus glabra, Quercus robur, Corylus avellana, Salix atrocinerea) which colonize the middle altitude watercourses of the rivers flowing into the Cantabrian Sea and the northern half of the Artabrian Gulf. Hyperico androsaemi-Coryletum avellanae comprises hazel and grey willow microforests associated with small tributaries and the high areas of the river basins within the thermo- and mesotemperate thermotypes of the territory. Finally, Violo palustris- Betuletum pubescentis is a tree association related to rivers flowing through the high mesotemperate and supratemperate areas of the northern ranges of Galicia and the Sierra de la Bobia in Asturias, continuing into the NW end of the Mino River basin. The above-mentioned forest types are all included in the 91E0* habitats of Appendix I of the Directive 92/43/EEC and are the habitat of a number of plant species of special interest for regional, Spanish and EU preservation policies.

Evaluation of triclopyr triethylamine for the control of wetland weeds

Several experiments evaluating the susceptibility of aquatic and wetland weeds to triclopyr TEA were carried out using potted plants Seedlings of grey willow (Salix cinerea) alder (Alnus glutinosa) and purple loosestrife (Lythrum salicaria) and cuttings of crack willow (S fragilis) primrose willow (Ludwigia peploides) water celery (Apium nodiflorum) water cress (Nasturtium officinale) and monkey musk (Mimulus guttatus) were collected in the field and grown in cultivation At least 2 months after potting up triclopyr TEA was applied to run off at rates between 025 and 5 v/v This resulted in excellent control of all weeds at all rates except for purple loosestrife which was not controlled well at the lowest rate

Residual effects of NPK fertilization on shrub growth in a Yukon boreal forest

Residual effects of nutrient additions were sustained in shrubs 4–8 years after fertilization stopped in a northern boreal forest in Yukon, Canada. We measured the growth rate of grey willow (Salix glauca L.) and bog birch (Betula glandulosa Michx.) twigs during the growing seasons of 1998, 2001, and 2002, 4–8 years after NPK fertilization from 1987 to 1994 had ceased. We also measured the nitrogen concentration of the 1998 growth tissue. Willow twigs had significantly higher growth rates in previously fertilized shrubs than control shrubs in these 3 years, even greater than differences observed during fertilization. Willow also had higher N concentration in fertilized twigs than control twigs. Birch growth was negatively correlated with hare abundance during the snowshoe hare (Lepus americanus) abundance cycle. Birch growth rate was higher in fertilized twigs than control twigs in 1998 during the hare peak, but fertilized birch twigs approached control levels by 2002 following the hare decline.Key words: Salix, Betula, productivity, nitrogen, fertilizer, herbivory.

Two subassociations of the Salici cinereae-Sphagnetum recurvi (Zólyomi 1931) Soó 1954

The physiognomy and the species composition of the Salici cinereae-Sphagnetum recurvi (Zólyomi 1931) Soó 1954 are variable in Hungary. This association has been divided into two new subassociations by the authors, due to the slight differences in their moss layer. As a representation they compared 27 phytocoenological relevés, made by 4 different botanists in 10 different mires, by multivariate analysis. Those peat moss dominated willow carrs, in which the dominant moss species are Sphagnum squarrosum and/or Sphagnum fimbriatum subsp. fimbriatum, are called Salici cinereae-Sphagnetum recurvi sphagnetosum squarrosi subass. nov., on the contrary those, in which any species of the Sphagnum recurvum agg. (S. fallax, S. angustifolium, S. flexuosum) and/or Sphagnum palustre are dominant, are called Salici cinereae-Sphagnetum recurvi sphagnetosum recurvi subass. nov. The two submitted subassociations of peat moss dominated grey willow carr are very similar. They could be found together or independently, on a terrestrial or on a floating mire. All of them are a part of the successional series of mire development, which can result a continental raised bog under recent climate, too.

The effects of NPK fertilization for nine years on boreal forest vegetation in northwestern Canada

Abstract. Plant productivity is limited by mineral nutrient availability in many boreal forest ecosystems. This study is an analysis of the growth responses of components of a boreal plant community (cryptogams, herbaceous and woody perennials, the dominant shrubs Salix glauca (grey willow) and Betula glandulosa (bog birch) and the dominant tree Picea glauca (white spruce), to the addition of an NPK fertilizer over a nine‐year period. The study was carried out in a low‐nutrient boreal forest ecosystem in the Yukon territory in northwestern Canada. The following predictions were tested: (1) that there would be an overall increase in abundance (measured either as cover, density, or dry mass) of all components of the vegetation, (2) that vegetation composition would change as more competitive species increased in abundance and (3) that initial community changes in response to fertilization would be transient. In general, all predictions were found to be true. Species composition changed rapidly in response to fertilizer. Graminoids (e.g. Festuca altaica) and some dicots (e.g. Mertensia paniculata and Achillea millefolium) increased in cover, while other dicots (e.g. Anemone parviflora), dwarf shrubs (e.g. Arctostaphylos uvaursi), bryophytes and lichens declined. There was a significant increase in the growth rate of the two dominant shrubs and of Picea, but not in the cone crop or seed production by Picea. Surveys after 1 or 2 years showed responses by the vegetation but more stable patterns of response did not emerge until after 5 or 6 years. There were consistent and directional changes in the percent cover of some of the herbaceous species on control plots. Growth rates of Salix and Betula varied considerably from year to year, independently of treatment. Long‐term studies are essential if we are to understand the role of nutrient limitation in this ecosystem.

The Fate of Groundwater Ammonium in a Lake Edge Wetland

AbstractThe removal of ammonium—nitrogen (NH4‐N) from groundwater flowing through a grey willow (Salix cinerea) and native raupo (Typha orientalis) lake edge wetland was investigated over 10 mo. Monthly groundwater sampling showed that more than 95% of incoming NH2‐N was removed by the wetland. Laboratory assays found that the potential for NH4‐N removal by nitrification and subsequent denitrification was significantly higher in the organic surface sediments than in deeper, sandy, root zone sediments. In a laboratory 15N‐tracer experiment, Salix cinerea and Typha orientalis readily assimilated NH2‐N from the root zone and were found to enhance the natural diffusion of NH4‐N up through the organic sediment layer and into the overlying water. Estimated rates of removal of NH2‐N by coupled nitrification‐denitrification and plant assimilation were 8 to 9 mg of N m−2 d−1 and 9 to 46 mg of N m−2 d−1, respectively. Assimilated N, returned to the overlying water‐sediment surface via litter fall may be subject to sequential mineralization, nitrification, and denitrification, resulting in gaseous N loss. Sixty‐five percent of the 15N in Salix leaf litter was transformed in such a way. The results of this study indicate that plants play a central role in the NH4‐N processing capacity of wetlands. The relevance of our findings to constructed wetland design is discussed.

Tackling the Bank Erosion Problem: (Re-)Introduction of Willows on Riverbanks

River regulation and increased shipping have resulted in serious erosion problems on the banks of the River Rhine. As an alternative for hard material or suppletion of sand, the Institute of Water Management and Waste Water Treatment is considering the use of willows for riverbank protection. Floodplain forests in The Netherlands are almost absent, mainly due to intensive cattle grazing. Various willow species were planted on sandy beaches at five locations along the River Rhine in 1990. After 2 growing seasons Common Osier (Salix viminalis) had the highest percentage survival and Grey Willow (S. cinerea) the lowest. Additionally, a survey has been planned to calculate roughness changes in the riverbed and wave extinction caused by the vegetation. Another goal of the project is to investigate the possibilities of establishment and development of a natural riverbank forest after excluding cattle.