Ecological ordination of the grass vegetation in Altai Krai

The article shows a variety of ordination methods used to analyze different types of vegetation and presents the results of the ordinal analysis of meadow (i.a. idle lands) and steppe phytocenoses that are widespread in Altai Krai. Ecological ordination is performed by means of the Detrended Correspondence Analysis (DCA) method. The ordination of grass communities is based on 616 complete geobotanical descriptions (330 - meadow, 286 - steppe). The article determines the position of community types on the gradients of humidification and soil richness-salinity for steppes and suggests the directions of the progressive successions of idle land communities in Altai Krai.

Steppe complex of the middle part of the Egorlyk valley (Stavropol Upland)

The article highlights the current state of plant communities in the steppe complex of Middle Yegorlyk.The patterns of distribution of grass communities depending on the area’s landscape-environmental features are shown.The main formations of dry (real), hemigalophytic and grass-cereal phytocenoses and their edaphic variants are indicated.The species of floristic nucleus of representative communities are given. The originality and regional features of thestudied steppes are associated with their border position in the contact zone of the eastern Black Sea plains steppes andthe Stavropol Upland.

Soil chemical legacies trigger species-specific and context-dependent root responses in later arriving plants

Soil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation, and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect on F. rubra, root foraging by D. deltoides decreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D. deltoides arose via either a root growth-dependent pathway (forb metabolome) or a root trait-dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants.

Population Genetics of Fusarium graminearum at the Interface of Wheat and Wild Grass Communities in New York

Fusarium graminearum is primarily understood as an agricultural pathogen affecting cereal crops, but its host range also includes diverse, noncultivated grasses ubiquitous across agricultural and natural environments. Wild grasses may select for the production of diverse toxin variants (chemotypes) and serve as reservoirs of genetic diversity or sources of disease-inciting inoculum. Populations at the intersection of wheat and wild grass communities were described using 909 isolates collected from wheat spikes, wild grass spikes, and overwintered wild grass stems found at natural and agricultural sites in regions of high and low crop production. Trichothecene (TRI) genotypes correlated to pathogen chemotype were predicted from two loci, and multilocus genotypes (MLGs) were determined using eight microsatellite loci. The genetic diversity of wild grass and wheat-derived populations was comparable, and their differentiation was low. Duplicate MLGs were rare even in samples collected from a single square meter, although they could be found in multiple hosts, environments, regions, and years. TRI genotype frequencies differed between region and land use. Admixture between TRI genotype-defined populations, which correspond to three previously described sympatric North American populations, was detected and was highest in a region with remote host communities and little agricultural production. Nonagricultural environments may maintain different pathogen TRI genotypes than wheat fields and provide an opportunity for recombination between isolates from different F. graminearum populations. A lack of structural barriers suggests that pathogen gene flow is uninhibited between wheat and wild grass communities, and the recovery of putative clones from multiple hosts and environments provides initial evidence that noncultivated grasses are a source of local and regional inoculum.

The experience of estimating the aboveground productivity dynamics of grass communities in the Malaya Sosva River floodplain (Nature Reserve "Malaya Sosva") taking into account weather, climate and hydrological features

This article is devoted to assessing the productivity of grass communities in the Malaya Sosva River floodplain (Reserve "Malaya Sosva"). The three-year studies (1986-1988) at six sample plots (SP) were conducted. The main goal was to evaluate the productivity and its relationship with hydrological and meteorological factors. The method of N.F. Khramtsova was used [1974], which allows to avoiding disturbance of vegetation on the SP, as well as performing statistical data processing. The obtained results reflected the close relationship of productivity with soil moisture, connecting to the position in the relief – aboveground biomass increases to the Malaya Sosva River. At the same time, the increase in biomass has a weak relationship with meteorological factors (temperature and precipitation), despite the weather contrasting seasons. The grass communities show relative stability by significant fluctuations in hydrological and weather conditions in different years. There is an inverse correlation between productivity and biodiversity. A similar trend was observed for the flood plain of the Ob River. But there is a significant range of values in the Ob River floodplain due to the extended flooding.