Viktoria Wagner

• PhD
• Professor (Assistant) at University of Alberta

Questions Community resistance to non‐native plant invasions results from intrinsic habitat characteristics, propagule pressure, and the presence of disturbance. Species identity further complicates this relationship due to pre‐existing adaptations. Despite these mechanisms being understood in isolation, their interplay is rarely explored in natura...

Kentucky bluegrass (Poa pratensis L.) is a perennial, cool-season grass that is widespread across all provinces and territories and first mentioned as an invasive species in 1879. It is represented in Canada by six subspecies, three of which are native, two introduced, and one native and introduced. As a group, the subspecies are found across a wid...

In response to non‐native plant invasions, many governments have established noxious weed lists to control and eradicate introduced invasive plants. However, invasive agronomic species are often unregulated, and the extent of their invasion across habitat types has never been determined. Using vegetation surveys across 222 plots, we investigated th...

Aim In salt‐affected environments, salinity shapes ecosystem functions and species composition. Apart from salinity, however, we know little about how soil chemical factors affect plant species. We hypothesized that specific ions, most of which contribute to salinity, co‐determine plant niche differentiation. We asked if the importance of ions diff...

Empirical invasion ecology is laden with high context dependency. If general mechanisms underlying invasion success exist, they should be detectable in species that share biological and ecological characteristics. We carried out a growth experiment with Agropyron cristatum, Bromus inermis and Poa pratensis (subsp. angustifolia), to better understan...

Aims In northwestern North America, montane meadows fed by vernal ground‐flow seepage occur scattered throughout an otherwise forested landscape on shallow soils over bedrock. Although their significance for biodiversity has been known, they have never been subject to systematic scientific research and thus, are not included in regional or national...

Questions Urbanisation has accelerated the spread of alien and apophytic species around the world including the drylands of continental inland Asia. However, few studies have examined the patterns and drivers of urban plant diversity in this region. We ask how habitat type, city size and macroclimate affect species richness and composition of alien...

Native prairie grasslands are a fundamental part of Canada's natural heritage, but these formerly extensive ecosystems have undergone declines due to grassland conversion and fragmentation. In addition, remaining native grasslands are threatened by invasive non-native plants, which can outcompete native flora and negatively impact ecological functi...

Artemisia frigida is a temperate grassland species that has the largest natural range among its genus, with occurrences across the temperate grassland biomes of Eurasia and North America. Despite its wide geographic range, we know little about the species’ distribution history. Hence, we conducted a phylogeographical study to test the hypothesis th...

Motivation Assessing biodiversity status and trends in plant communities is critical for understanding, quantifying and predicting the effects of global change on ecosystems. Vegetation plots record the occurrence or abundance of all plant species co‐occurring within delimited local areas. This allows species absences to be inferred, information se...

Questions European woodlands harbor at least 386 alien plant species but the factors driving local invasions remain unknown. By using a large vegetation‐plot database, we asked how local richness and abundance of alien species vary by regions, elevation, climate, soil properties, human disturbance, and habitat types. Location Western, Central and S...

The present Special Feature comprises 8 articles by 47 authors from 10 countries. The contributions highlight different aspects of grassland research and focus on several study organisms and scales: JANIŠOVÁ et al. (2020a) studied relationships between traditional farming systems and recent plant diversity in grasslands of the alliances Arrhenather...

Mountain caribou, a behaviourally and genetically distinct set of ecotypes of the Woodland caribou (Rangifer tarandus caribou) restricted to the mountains of western Canada, have undergone severe population declines in recent decades. Although a broad consensus exists that the ultimate driver of these declines has been the reduction of habitat upon...

The Inland Northwest is home to natural meadows, that occur interspersed in its mid-elevational zone (" Bedrock Meadows"). They have never been studied, mapped and inventoried by scientists and hence do not exist in the public eye. Their small size could make them disproportionately vulnerable to the pressures of land-use change. As a consequence,...

Aims: Vegetation-plot records provide information on the presence and cover or abundance of plants co-occurring in the same community. Vegetation-plot data are spread across research groups, environmental agencies and biodiversity research centers and, thus, are rarely accessible at continental or global scales. Here we present the sPlot database,...

GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). Following a previous Long Database Report (Dengler et al. 2018, Phytocoenologia 48, 331–347), we provide here the first update on content and functionality of Gra...

Seit 14 Jahren werden von Mitgliedern der Eurasian Dry Grassland Group (EDGG) und deren Vorgängerorganisationen Grasland-Sonderteile (Special Features) in Tuexenia herausgegeben. Das diesjährige Special Feature mit dem Titel Wiederherstellung, Überwachung, Schutz und Soziologie des halbnatürlichen und natürlichen Graslands in Mitteleuropa umfasst s...

Questions: Vegetation-plot records provide information on presence and cover or abundance of plants co-occurring in the same community. Vegetation-plot data are spread across research groups, environmental agencies and biodiversity research centers, and thus, are rarely accessible at continental or global scales. Here we present the sPlot database,...

The species richness–productivity relationship is one of the most debated patterns in ecology. Species coexistence theory suggests that it could be tightly linked to the type of nutrient limitation (no limitation, single‐nutrient limitation, colimitation by several nutrients). Yet, the effects of nutrient limitation on the species richness–producti...

Zusammenfassung Seit 13 Jahren werden von Mitgliedern der Eurasian Dry Grassland Group (EDGG) und deren Vor-gängerorganisationen Grasland-Sonderteile (Special Features) in Tuexenia herausgegeben. Das diesjäh-rige Special Feature trägt den Titel Naturschutz, Pflege und Wiederherstellung des halbnatürlichen und natürlichen Graslands in Mitteleuropa....

GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (relevés) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots...

Understanding patterns and drivers of phytodiversity as well as ecological scaling laws and assembly rules constitute core interests both of vegetation ecologists and macroecologists. To enhance our understanding of these issues, we compiled the new “Database of Scale-Dependent Phytodiversity Patterns in Palaearctic Grasslands” (GrassPlot; GIVD ID...

Natural resource managers commonly use herbicides to control invasive weeds. This practice, however, can lead to secondary invasion by other invasive plants, unless measures such as seeding are taken to promote natives. Although there is evidence that seeding immediately after herbicide treatment adversely affects germination, there is little infor...

Aim Soil pH is considered an important driver of fine‐scale plant species richness in terrestrial ecosystems. However, it is unclear to what extent this relationship is influenced by precipitation, which often directly affects both soil pH and species richness. We asked: (1) what is the relationship between fine‐scale vascular plant species richnes...

The Database of Scale-Dependent Phytodiversity Patterns in Palaearctic Grasslands GrassPlot (GrassPlot; EU-00-003; http://bit.ly/2qKTQt2) is a collaborative project within the Eurasian Dry Grassland Group (EDGG; http://www.edgg.org/). It was initiated with an international workshop in Bayreuth in spring 2017 and aims at complementing the European V...

European environmental policy mandates that biodiversity loss should be halted through restoration. However, knowledge about the efficacy of different restoration treatments for lowland meadows is still incomplete. Our study monitored two restoration projects in South-East Austria that served as compensation measures for the loss of species-rich gr...

Aim Woodlands make up a third of European territory and carry out important ecosystem functions, yet a comprehensive overview of their invasion by alien plants has never been undertaken across this continent. Location Europe. Methods We extracted data from 251,740 vegetation plots stored in the recently compiled European Vegetation Archive. After...

Million of acres of US wildlands are sprayed with herbicides to control invasive species, but relatively little is known about non-target effects of herbicide use. We combined greenhouse, field and laboratory experiments involving the invasive forb spotted knapweed (Centaurea stoebe) and native bunchgrasses to assess direct and indirect effects of...

Understanding patterns and drivers of phytodiversity as well as ecological scaling laws and assembly rules constitute core interests both of vegetation ecologists and macroecologists. To enhance our understanding of these issues, we compiled the new “Database of Scale-Dependent Phytodiversity Patterns in Palaearctic Grasslands” (GrassPlot; GIVD ID...

Fine-grain biodiversity data sampled over broad biogeographic regions is essential for understanding the drivers of macroecological patterns. These patterns and their drivers depend on spatial grain and extent, but the exact effect of these two components of scale on biodiversity is not well understood and limited by the lack of fine-grain biodiver...

Soil pH is a key predictor of plant species occurrence owing to its effect on the availability of nutrients and phytotoxic metals. Although regional differences in realized soil pH niche (‘niche shifts’) have been reported since the 19th century, no study has disentangled how they are influenced by spatial differences in substrate availability, mac...

Semi-dry grasslands were once widely distributed communities, but today they represent some of the most vulnerable habitats in Central Europe. European and national legislation and non-governmental organizations have managed to protect some of the remaining fragments. However, despite their status as Natura 2000 habitats, they are often endangered...

Semi-dry grasslands were once widely distributed communities, but today they represent some of the most vulnerable habitats in Central Europe. European and national legislation and non-governmental organizations have managed to protect some of the remaining fragments. However, despite their status as Natura 2000 habitats, they are often endangered...

Seit 11 Jahren werden von Mitgliedern der Eurasian Dry Grassland Group (EDGG) und deren Vor-gängerorganisationen Grasland-Sonderteile in Tuexenia herausgegeben. Der diesjährige Sonderteil präsentiert sechs Artikel mit unterschiedlichen Fragestellungen zu Trockenrasen und verwandten Gras-landtypen aus sechs europäischen Ländern: Belgien, Bosnien-Her...

Correct spelling of taxon names in vegetation databases is a fundamental prerequisite for many data processing steps. However, manual detection and correction of spelling mistakes is inefficient, prone to errors and non-reproducible, especially when scanning large databases. Here, I review six software tools that spell-check taxon names in vegetati...

In North America, herbicides are commonly used to control non‐native invasive plants on public wildlands. Little is known about the magnitude, efficacy and financial costs of this practice, although this information is crucial for policymakers, researchers, land managers, pesticide producers and the general public. In Canada and Mexico, herbicide u...

Background: A taxonomic reference list is an indispensable tool to sample, manage and match biodiversity data from different sources. Merging vegetation databases or combining them with taxon-related attributes needs reliable and consistent information about the taxon concepts used and an appropriate naming. Aim: Creating a “taxonomic backbone” of...

Local adaptation is used as a criterion to select plant materials that will display high fitness in new environments. A large body of research has explored local adaptation in plants, however, to what extent findings can inform management decisions has not been formally evaluated. We assessed local adaptation literature for six key experimental met...

Invasion of different habitats differs greatly with that of temperate woodlands being characterized by relatively low levels of invasion. However, evidence is accumulating that alien species of trees are increasingly colonizing woodlands, in particular floodplain woodlands. Here, we used 346 stratified relevés (154 plots in floodplain and 192 in no...

This is the original R script used to prepare and analyze data for the publication"Wagner, V., Antunes, P.M., Irvine, M., Nelson, C.R. (2016)Herbicide usage for invasive non-native plant management in wildland ares of North America. Journal of Applied Ecology"Accompanying data:(1) herbicide usage data from the BLM, FSW and NPS (BLM_data.txt, FWS_da...

This is the original R script used to prepare and analyze data for the publication"Wagner, V., Antunes, P.M., Irvine, M., Nelson, C.R. (2016)Herbicide usage for invasive non-native plant management in wildland ares of North America. Journal of Applied Ecology"Accompanying data:(1) herbicide usage data from the BLM, FSW and NPS (BLM_data.txt, FWS_da...

Genetic diversity is important for species' fitness and evolutionary processes but our knowledge on how it varies across a species distribution range is limited. The abundant centre hypothesis (ACH) predicts that populations become smaller and more isolated towards the geographic range periphery - a pattern that in turn should be associated with de...

We investigated early spontaneous colonisation patterns during semi-dry grassland restoration at two sites in SE Austria. The sites were left to regenerate passively without addition of plant propagules on a former arable field and an apple orchard. The sites were prepared only by ploughing (arable field) or clear cutting (apple orchard) and subseq...

Background/Question/Methods Millions of gallons of herbicides are applied yearly to control invasive weeds, but their impact on non-target soil biota is little known. We designed an experiment to assess the direct and indirect effects of the broadleaf-specific herbicide Tordon on arbuscular mycorrhizal fungi (AMF), a group of ubiquitous root symb...

Biological soil crusts (BSCs) provide important ecosystem services in dryland regions, including erosion control and contribution to nitrogen and CO2 fixation. As soil microorganisms are still rarely studied within the context of biodiversity planning, we describe, as a contribution to the Soil Crust International project, an approach that addresse...

Herbicides are widely used to control invasive non-native plants in wildlands, yet there is little information on their non-target effects, including on native plants that are intended to benefit from the treatment. Effects at the seed stage have been particularly understudied, despite the fact that managers commonly seed native plants immediately...

There is wide consensus that ongoing deforestation contributes to global warming and poses a threat to species diversity. Less understood is whether the practice of creating plantations might also erode genetic diversity and undermine the genetic structure of tree populations. We tested these hypotheses in natural and planted populations of Pinus b...

Question The mountains of NW N orth A merica are home to natural meadows that cover large areas at the timberline. The vegetation of these meadows has been the topic of few local studies, and little is known of species composition turnover across mountain ranges and along the latitudinal gradient. We sampled and analyzed community composition along...

In afforestation, silvicultural processes of raising and planting seedlings under certain conditions can yield contrasting outcomes in tree stock performance. Moderate nursery conditions may select against stress tolerance whereas planting seedlings in stressful environments at afforestation sites may select for higher stress tolerance compared to...

A highly selfing breeding system affects gene flow, which may have consequences for patterns of genetic variation and differentiation on both the population and species level. Feather grasses (Stipa spp.) are dominant elements of Eurasian steppes that persist in Central Europe in scattered isolated populations that are of great conservation interes...

A common assumption in ecology and evolutionary biology is that genetic diversity declines and differentiation increases toward the edge of a species’ geographic range, where populations tend to be smaller and more isolated. We tested these predictions in a characteristic Eurasian steppe plant, Stipa pennata, by inspecting 230 AFLP bands in 26 popu...

Nuclear energy is a potential solution to electricity demand but also entails risks. Policy debates on nuclear accidents have focused primarily on negative impacts on humans. Although such impacts are important, we argue that policy debates must also consider the consequences for biodiversity and ecosystem services. We reviewed 521 studies conducte...

Intraspecific genetic variation is essential for the performance and evolution of species. Populations at a species' geographic range periphery receive considerable attention in biogeography and conservation because they are smaller and spatially more isolated than central populations, a pattern expected to lead to higher genetic differentiation an...

Dry weight of plants from populations in A) Europe and B) Asia grown in ‘home soil’ and in sterile ‘control soil’ (Experiment 1). A linear mixed-effects model showed that soil treatment and region had a significant effect on dry weight: FSoil treatment = 25.62, degrees of freedom (d.f.) = 1,187, P<0.001, FRegion = 5.63, d.f. = 1,8, P = 0.045, FSoil...

Repeated measures analysis of plant growth during Experiment 3. Plant height was measured on individuals at the beginning and every third week of a nine week period and used as a response variable of the fixed effects time, soil treatment (‘home soil’, ‘away soil’ from the other region), region and their interaction. Population and individual neste...

Linear mixed-effects models to test for local adaptation within regions (Experiment 2). Dry weight was used as a function of the fixed effects geographic distance, region (and block). Geographic distance denotes the distance between the population of the plant and the soil inoculum. Models were constructed in two ways: A) from the perspective of pl...

Repeated measures analysis of plant growth during Experiment 2. Plant height was measured on individuals at the beginning and every third week of a nine week period and used as a response variable of the fixed effects time, geographic distance, and their interaction. Geographic distance denotes the distance between the population of the plant and t...

Dry weight of plants as a function of geographic distance and region (Experiment 2). Points represent dry weight of plants for Europe and Asia, respectively. Lines show the fitted linear mixed-effects model as predicted by the fixed effects geographic distance, region and their interaction for plants growing in soil from increasingly distant popula...

Dry weight of plants from populations in A) Europe and B) Asia grown in ‘home soil’ and ‘away soil’ from the other region (Experiment 3). A linear mixed-effects model showed that soil treatment, region and their interaction did not significantly influence dry weight production in plants: FSoil treatment = 0.13, d.f. = 1,184, P = 0.718, FRegion = 4....

Chemical properties of field collected soil and sterilized background soil used in the experiment. (DOC)

Repeated measures analysis of plant growth during Experiment 1. Plant height was measured on individuals every third week within a nine week period and used as a response variable of the fixed effects time, soil treatment (‘home soil’, ‘control soil’), region and their interaction. Including plant population or the interaction between plant populat...

Soil biota effects are increasingly accepted as an important driver of the abundance and distribution of plants. While biogeographical studies on alien invasive plant species have indicated coevolution with soil biota in their native distribution range, it is unknown whether adaptation to soil biota varies among populations within the native distri...

The abundant centre hypothesis predicts that changing environmental conditions are detrimental to a species’ abundance and performance towards the periphery of its range. We tested these predictions for the perennial grass Stipa capillata, a species that is commonly found in steppes of Asia but is rare at its north-western range edge, in central Eu...

Stipa capillata L. (Poaceae) is a rare grassland species in Central Europe that is thought to have once been widespread in post-glacial times. Such relict species are expected to show low genetic diversity within populations and high genetic differentiation between populations due to bottlenecks, long-term isolation and ongoing habitat fragmentatio...