Lauchlan Hugh Fraser

• PhD
• Professor (Full) at Thompson Rivers University

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominat...

Mine reclamation succeeds when healthy, self-sustaining ecosystems develop on previously mined lands. Regulations require reclamation of ecosystem services; however, there are few specified targets, and those that are presented are vague. Sequencing genomic DNA and transcribed RNA from environmental samples may provide critical supportive informati...

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multi-year droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Anthropogenic biodiversity decline threatens the functioning of ecosystems and the many benefits they provide to humanity¹. As well as causing species losses in directly affected locations, human influence might also reduce biodiversity in relatively unmodified vegetation if far-reaching anthropogenic effects trigger local extinctions and hinder re...

We examined the effects of different mowing heights on the plant and soil characteristics of an irrigated and fertilized perennial cropping system in the central interior of British Columbia, Canada primarily composed of Medicago sativa, Phleum pratense, and Trifolium pratense. Mowing treatments included cutting heights of 0 cm, 5 cm, 10 cm, 15 cm,...

Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in...

Earth harbours an extraordinary plant phenotypic diversity¹ that is at risk from ongoing global changes2,3. However, it remains unknown how increasing aridity and livestock grazing pressure—two major drivers of global change4–6—shape the trait covariation that underlies plant phenotypic diversity1,7. Here we assessed how covariation among 20 chemic...

Mineral-associated organic carbon (MAOC) constitutes a major fraction of global soil carbon and is assumed less sensitive to climate than particulate organic carbon (POC) due to protection by minerals. Despite its importance for long-term carbon storage, the response of MAOC to changing climates in drylands, which cover more than 40% of the global...

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in dryla...

Prescribed burning can be an effective land management tool. Here, we study changes in plant diversity and composition following experimental fire disturbance in microcosm units extracted from a twenty-five-year-old historically reclaimed grassland located at Highland Valley Copper mine in British Columbia (B.C.), Canada. Experimental microcosm uni...

Our understanding of plant functional trait variation among populations and how this relates to local adaptation to environmental conditions is largely shaped by above‐ground traits. However, we might expect below‐ground traits linked to resource acquisition and conservation to vary among populations that experience different environmental conditio...

Climate change is increasing the frequency and severity of short-term (~1 y) drought events—the most common duration of drought—globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in t...

The diversity-productivity relationship predicts a positive effect of plant species richness on primary productivity. One key mechanism predicted to underlie this relationship is the effect of plant diversity on the suppression of plant antagonists, including invertebrate herbivores, plant diseases, antagonistic plants in an agricultural context (i...

Warming and changing precipitation can alter the performance of native grasses that are essential to grassland ecosystems. Native grasses may respond to changing climate by phenotypic plasticity or lose their current ranges. Establishing plant species from southern, warmer provenances may reduce the likelihood of biodiversity loss and improve resto...

Warming can decrease feeding activity of soil organisms and affect biogeochemical cycles. The ant Formica manchu is active on the nest surface and prefers a hot, dry environment; therefore, warming may provide a favourable environment for its activities. We hypothesized that F. manchu benefit from warming and mitigate the negative effects of warmin...

Warming and changing water amount can alter the outcome of biotic interactions in native and exotic plants between facilitation and competition. Exotic plants may adapt better to changing environmental conditions, such that they may compete better than native plants. We conducted competition trials for four plant species, two exotic forbs (Centaure...

Introduction Traditional approaches to collecting large-scale biodiversity data pose huge logistical and technical challenges. We aimed to assess how a comparatively simple method based on sequencing environmental DNA (eDNA) characterises global variation in plant diversity and community composition compared with data derived from traditional plant...

Our knowledge of microbial biogeography has advanced in recent years, yet we lack knowledge of the global diversity of some important functional groups. Here, we used environmental DNA from 327 globally collected soil samples to investigate the biodiversity patterns of nitrogen-fixing bacteria by focusing on the nifH gene but also amplifying the ge...

Environmental circumstances shaping soil microbial communities have been studied extensively. However, due to disparate study designs, it has been difficult to resolve whether a globally consistent set of predictors exists, or context-dependency prevails. Here, we used a network of 18 grassland sites (11 of those containing regional plant productiv...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Invasive plants such as spotted knapweed (Centaurea stoebe) are particularly detrimental to fragile ecosystems like semi-arid grasslands in the interior British Columbia, impacting aboveground and belowground ecology. Physical removal of C. stoebe has been one of the most popular invasive species management strategies, but the impact of C. stoebe r...

Classical theory identifies resource competition as the major structuring force of biotic communities and predicts that (i) levels of dominance and richness in communities are inversely related, (ii) narrow niches allow dense “packing” in niche space and thus promote diversity, and (iii) dominants are generalists with wide niches, such that locally...

Mining activities are often severely disruptive to the landscape, and a major barrier to reclamation after mining is lack of quality topsoil. This research addresses knowledge gaps in the industry by exploring the compositional nature of topsoil stockpiles and their ability to facilitate post-mining revegetation after long-term storage. To do this,...

Timber harvesting in riparian zones without leaving a buffer can increase the likelihood of livestock grazing along streams. The wet soil around small streams can accentuate the negative impact of grazing, affecting vegetation, as well as other ecosystem characteristics. In this study, we tested the effectiveness of using coarse woody debris, a rea...

Arbuscular mycorrhizal (AM) fungi are a ubiquitous group of plant symbionts, yet processes underlying their global assembly — in particular the roles of dispersal limitation and historical drivers — remain poorly understood. Because earlier studies have reported niche conservatism in AM fungi, we hypothesized that variation in taxonomic community c...

Aim Organisms on our planet form spatially congruent and functionally distinct communities, which at large geographical scales are called “biomes”. Understanding their pattern and function is vital for sustainable use and protection of biodiversity. Current global terrestrial biome classifications are based primarily on climate characteristics and...

The global use of off-road vehicles (ORVs) in natural environments has accelerated rapidly over the last few decades, resulting in significant social and environmental consequences. As the demand, use, and promotion of light-duty ORVs like all-terrain vehicles (ATVs), motorcycles, four-wheel drive trucks and sport utility vehicles (SUVs) increases...

The land application of biosolids can be subject to questions and concerns, suggesting a gap exists with public perception of biosolids. There is opposition amongst a segment of the population regarding the land application of biosolids in the Southern Interior of British Columbia in Canada. Kamloops and Merritt communities were assessed through a...

Environmental circumstances shaping soil microbial communities have been studied extensively, but due to disparate study designs it has been difficult to resolve whether a globally consistent set of predictors exists, or context-dependency prevails. Here, we used a network of 18 grassland sites (11 sampled across regional plant productivity gradien...

Aim We explore long-term plant community responses 17 years after a one-time application of biosolids (0, 50, 100, 150, 200, 250 dry Mg∙ha⁻¹) to determine (1) whether the land application of biosolids on mine tailings, seeded with agronomic grass-legume mixture, affects long-term plant community responses, (2) how application rates and soil texture...

Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait variation, but their roles differ among traits. In short-lived plants, reproductive traits may be more genetically determined due to their impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-t...

Phytostabilization is the use of plants and soil amendments to physically stabilize and remediate contaminated mine wastes and to control wind and water erosion in semiarid environments. The aim of this study was to evaluate two native bunchgrass species’ (Pseudoroegneria spicata and Festuca campestris) biomass accumulation and metals uptake respon...

Invasive plants cause changes to native plant communities and nutrient cycling, and by doing so, may alter the amount and quality of habitat available for animals at multiple trophic levels, including arthropods. Arthropods are generally abundant, diverse, and contribute to energy flow and nutrient cycling and are, therefore, an important group to...

The arbuscular mycorrhizal (AM) fungi are a globally distributed group of soil organisms that play critical roles in ecosystem function. However, the ecological niches of individual AM fungal taxa are poorly understood. We collected > 300 soil samples from natural ecosystems worldwide and modelled the realised niches of AM fungal virtual taxa (VT;...

Several different hypotheses account for the success of introduced species in new environments. Experimental studies show a negative native-exotic richness relationship (NERR), while observational studies suggest that this relationship is usually positive. Increased resource availability and environmental variation can also enable introduced specie...

Phenotypic plasticity can mask population genetic differentiation, reducing the predictability of trait-environment relationships. In short-lived plants, reproductive traits may be more genetically determined due to their direct impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a m...

Questions Biosolids are a source of nutrient‐rich organic material that can be used to improve degraded or disturbed soils. Research on vegetation responses to the land application of biosolids has increased in the past 20 years, but there is no consensus on how plant communities respond to biosolids applications. What factors influence productivit...

Theories and models attempt to explain how and why particular plant species grow together at particular sites or why invasive exotic species dominate plant communities. As local climates change and human‐use degrades and disturbs ecosystems, a better understanding of how plant communities assemble is pertinent, particularly when restoring grassland...

Biological invasions are of particular concern in grasslands, as these systems are highly susceptible to changes in ecosystem energy flows following invasions by exotic plants. Spotted knapweed (Centaurea stoebe L.), a Eurasian, perennial forb, is considered one of the most ecologically harmful invasive plants in North American grasslands and may l...

Sites disturbed through mining practices can be challenging to restore with native vegetation, as the path of ecological succession is often unknown and hard to predict. We conducted an establishment study that explored restoration strategies to increase native vegetation on a newly formed stockpile of soil at New Gold’s New Afton Mine in British C...

Aim Plant species continue to be moved outside of their native range by human activities. Here, we aim to determine whether, once introduced, plants assimilate into native communities or whether they aggregate, thus forming mosaics of native‐ and alien‐rich communities. Alien species might aggregate in their non‐native range owing to shared habitat...

TRY, the Plant Trait Database, has operated for 12 years and is progressing into its third generation. Kattge et al. (2019) provide an important overview and reflection on the past 12 years of the TRY database, with a discussion on future direction. At the time I write this, the TRY database lists 11,850,781 trait records, 279,875 plant taxa, and 2...

Plant traits, such as height or specific leaf area, are expressions of plant performance and are important indicators of ecosystem function. Here, the TRY plant database is highlighted as the most comprehensive archive of global plant data, with open access to the public.

The effect of biodiversity on primary productivity has been a hot topic in ecology for over 20 years. Biodiversity-productivity relationships in natural ecosystems are highly variable, although positive relationships are most common. Understanding the conditions under which different relationships emerge is still a major challenge. Here, by analyzi...

Grasslands comprise approximately 26 percent of the total land area and 80 percent of agriculturally productive land, as well as providing important services such as hydrologic control, biodiversity reserves, and a carbon sink. Primary plant production, the conversion of sunlight energy and carbon into plant biomass, is a key ecosystem service prov...

Herbivores alter plant biodiversity (species richness) in many of the world’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet,...

Reduced precipitation treatments often are used in field experiments to explore the effects of drought on plant productivity and species composition. However, in seasonally snow-covered regions reduced precipitation also reduces snow cover, which can increase soil frost depth, decrease minimum soil temperatures and increase soil freeze–thaw cycles....

Evaluation of the Use of Wetlands in Arsenic Sequestration of Mine-Influenced Effluent using Synchrotron XRF and XANES Spectroscopy - Volume 24 Supplement - Connor Arduini, Lauchlan Fraser, Trevor Flynn, Lisa Van Loon, Neil Banerjee

Management and reclamation of industrial mine sites for carbon (C) sequestration is an emerging technique for offsetting anthropogenic C emissions. Land application of municipal biosolids is an effective method for amending closed tailings storage facilities and providing the nutrients to establish a vegetative cover. Biosolids applications can inf...

We investigated the impacts of the Mount Polley tailings impoundment failure on chemical, physical, and microbial properties of substrates within the affected watershed, comprised of 70 hectares of riparian wetlands and 40 km of stream and lake shore. We established a biomonitoring network in October of 2014, two months following the disturbance, a...

Transect origination coordinates are provided below for the 60 sites (in decimal degree format) with date, local (Pacific Standard) time of day (TOD) and site ID codes for the biomonitoring network. (PDF)

Correlation of soil moisture and organic matter contents. SOM–soil organic matter. Linear (green) and 2nd order polynomial (red) contours are included. (PDF)

Soil organic matter (g/kg) content of samples collected from all three layers depicted according to geographical location. Point size reflects Soil organic matter content (g/kg). (PDF)

Species richness (sobs) in Polley Lake microbiomes. Point size reflects relative species richness (estimated as number of distinct OTUs). (PDF)

Chemistry of the sediment layer pore water. Major water bodies are labelled as follows: BJL = Bootjack Lake, HAZ = Hazeltine Creek, POL = Polley Lake, QUE = Quesnel Lake. (PDF)

Landscape-scale distribution of OTU1. Relative abundance (% of total bacterial read counts) is expressed for the three sample types. (PDF)

Boxplots of SOM (g/kg) contents measures at all sites compared across layers and habitats. (PDF)

Pore water pH, dissolved oxygen (mg/L) and conductivity (μS/cm). Box-whisker plots reflect medians, quartiles and outliers by lake/stream. (PDF)

Water quality metric means ± standard error. Fields in grey marked with (—) yielded insufficient data for reliable comparisons (<4 observations). (PDF)

Global analyses of bird communities along elevation gradients suggest that bird diversity on arid mountains is primarily limited by water availability, not temperature or altitude. However, the mechanism by which water availability, and subsequently primary productivity, increases bird diversity is still unclear. Here we evaluate two possible mecha...

Broad vegetation types from along the gradient. (TIF)

List and description of species encountered. (PDF)

Relationship between elevation and NDVI and elevation and soil moisture. (TIF)

Tailings management is one of several challenges faced by mines operating in dry environments. If tailings are exposed, with no vegetative cover, dust from mine sites can spread over long distances through eolian dispersion and water erosion, posing a risk to human and environmental health. Phytostabilization is a remediation technique which involv...

Livestock grazing is a prevalent land use in western North American intermountain wetlands, and physical and biotic changes related to grazing-related disturbance can potentially limit wetland habitat value for waterfowl. We evaluated breeding waterfowl use in 34 wetlands in relation to water retention, amount of wetlands on the landscape, and live...

We used geographic datasets and field measurements to examine the mechanisms that affect soil carbon (SC) storage for 65 grazed and non-grazed pastures in southern interior grasslands of British Columbia, Canada. Stepwise linear regression (SR) modeling was compared with random forest (RF) modeling. Models produced with SR performed better than tho...

This perspective documents current thinking around climate actions in Canada by synthesizing scholarly proposals made by Sustainable Canada Dialogues (SCD), an informal network of scholars from all 10 provinces, and by reviewing responses from civil society representatives to the scholars’ proposals. Motivated by Canada’s recent history of repeated...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

Figure S1: Database schema. Diversity data in yellow, GIS data in green and Catalogue of Life data in blue. The diversity tables datasource, study, site, measuredtaxon and diversitymeasurement follow the structure described in ‘Methods’ in the main text and in Hudson et al. (2014): a datasource is associated with one or more study records, each of...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

Climate change is expected to alter precipitation patterns. Droughts may become longer and more frequent, and the timing and intensity of precipitation may change. We tested how shifting precipitation patterns, both seasonally and by frequency of events, affects soil nitrogen availability, plant biomass and diversity in a shrub-steppe temperate gra...

Meta data, plant community, functional group, PRS probes N, soil extractable N. (XLSX)

Plant traits affect the success or failure of plants to establish, grow, and reproduce. Although we have an increased understanding of certain individual plant traits and their relative effects on performance and fitness, it is a challenge to predict relative similarity of traits between neighbouring plants. Assembly rules suggest that abiotic filt...

Saline wetland and ponds in Canada can be found in arid and semi-arid regions where evaporation exceeds precipitation. An increase in salinity can reduce plant growth and affect competitive interactions between plants. A field experiment and a greenhouse experiment tested the effects of salinity and competition on the growth of two wetland plants,...

Logging and burning of the resultant woody debris is a management tool to reduce fire risk. Burning of the debris as piles affects the underlying soil biota and soil physical and (or) chemical properties. The resulting disturbance created by the burns may create opportunities for the establishment and spread of non-native plant species. Here, we te...

Understanding scaling relationships in ecology can foster the development of valuable predictive tools and also pave the ground towards the formulation of better mechanistic models. The species–area relationship (SAR) is a classical example of an empirical relationship between species richness (S) and sampling area (A). This relationship arises fro...

The addition or removal of predators from food webs by humans can have profound effects on the interactions between species. However, predators and primary producers are inextricably linked by the flow of energy through ecosystems. In temperate grasslands energy flow through ecosystems is often limited by water availability to plants. So, if the nu...

The addition or removal of predators from food webs by humans can have profound effects on the interactions between species. However, predators and primary producers are inextricably linked by the flow of energy through ecosystems. In temperate grasslands energy flow through ecosystems is often limited by water availability to plants. So, if the nu...

Tredennick et al. criticize one of our statistical analyses and emphasize the low explanatory power of models relating productivity to diversity. These criticisms do not detract from our key findings, including evidence consistent with the unimodal constraint relationship predicted by the humped-back model and evidence of scale sensitivities in the...

El estudio de la riqueza y la composición de especies vegetales de un humedal es esencial a la hora de estimar su importancia ecológica y sus servicios ecosistémicos, especialmente cuando éste está sujeto a perturbaciones humanas. El lago Poyang, situado en el curso medio del río Yangtsé (China central) constituye la mayor superfície de agua dulce...

Laanisto and Hutchings claim that the local species pool is a more important predictor of local plant species richness than biomass and that when the species pool is considered, there is no hump-backed relationship between biomass and richness. However, we show that by calculating a more appropriate measure of species pool, community completeness,...