Foliar fungal pathogens and grassland biodiversity

Allan, Eric; Ruijven, Jasper van; Crawley, Michael J.

doi:10.1890/09-0859.1

Cited by 119 publications

(99 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Patterns of plant demography consistent with Janzen-Connell effects are found in tropical forests (Metz et al 2010), temperate forests (Martin and Canham 2010), and grasslands (Petermann et al 2008, Allan et al 2010, and throughout the early life stages of trees, from seeds (Kotanen 2007) to seedlings to saplings (Gonzalez et al 2010). Patterns of plant demography consistent with Janzen-Connell effects are found in tropical forests (Metz et al 2010), temperate forests (Martin and Canham 2010), and grasslands (Petermann et al 2008, Allan et al 2010, and throughout the early life stages of trees, from seeds (Kotanen 2007) to seedlings to saplings (Gonzalez et al 2010).…”

Section: Discussionsupporting

confidence: 53%

Evaluating the impacts of multiple generalist fungal pathogens on temperate tree seedling survival

Hersh

Vilgalys

Clark

2012

Ecology

133

137

View full text Add to dashboard Cite

Host-specific mortality driven by natural enemies is a widely discussed mechanism for explaining plant diversity. In principle, populations of plant species can be regulated by distinct host-specific natural enemies that have weak or nonexistent effects on heterospecific competitors, preventing any single species from becoming dominant and thus promoting diversity. Two of the first steps in exploring the role of natural enemies in diversity regulation are to (1) identify potential enemies and (2) evaluate their levels of host specificity by determining if interactions between any one host and its enemy have equivalent survival impacts on co-occurring host species. We developed a bioinformatics framework to evaluate impacts of potential pathogens on seedling survival, for both single and multiple infections. Importantly, we consider scenarios not only if there are specialist pathogens for each plant, but also when generalist pathogens have differential effects on multiple host species, and when co-infection has species-specific effects. We then applied this analytical framework to a field experiment using molecular techniques to detect potential fungal pathogens on co-occurring tree seedling hosts. Combinatorial complexity created by 160 plant-fungus interactions was reduced to eight combinations that affect seedling survival. Potential fungal pathogens had broad host ranges, but seedling species were each regulated by different combinations of fungi or by generalist fungi that had differential effects on multiple plant species. Soil moisture can have the potential to shift the nature of the interactions in some plant-fungal combinations from neutral to detrimental. Reassessing the assumption of single-enemy-single-host interactions broadens the mechanisms through which natural enemies can influence plant diversity.

show abstract

Section: Discussionsupporting

confidence: 53%

Evaluating the impacts of multiple generalist fungal pathogens on temperate tree seedling survival

Hersh

Vilgalys

Clark

2012

Ecology

133

137

View full text Add to dashboard Cite

show abstract

“…In natural grasslands, fungal pathogens are predicted to maintain plant species co‐existence by lowering the abundance of dominant plant species (Petermann et al ., ; Allan et al ., ). A previous study in our plots revealed that A .…”

Section: Discussionmentioning

confidence: 97%

Grazing Intensity Affects Communities of Culturable Root‐Associated Fungi in a Semiarid Grassland of Northwest China

et al. 2017

View full text Add to dashboard Cite

Intensive grazing by large herbivores is known to result in the degeneration of grassland worldwide. However, little is known about how grazing affects the fungi living in roots, especially those with septate hyphae. We investigated grazing intensity effects on culturable root‐associated fungi (c‐RAF) of three dominant plant species; Artemisia capillaris, Lespedeza davurica, and Stipa bungeana, in a semiarid grassland of northwest China. Plant roots were sampled from four grazing intensities at four sampling dates. The total colonization rate of c‐RAF was not affected by grazing intensity, but the diversity of c‐RAF displayed a hump‐shaped trend with grazing intensities. Few c‐RAF were present in all plant species, with most of them being confined to only one or two plant species. The 16 most commonly isolated species were selected to investigate their effects on plant growth and health. Three Fusarium species were most pathogenic c‐RAF. Three dark‐sterile species did not affect growth parameters, regardless of host plants. With A. capillaris, the occurrence of Fusarium spp. was highest in the control plots, while with S. bungeana, the occurrence tended to increase as the grazing intensity increased. Two dark‐sterile species, including Darksidea alpha, in L. davurica roots increased with grazing intensities; in contrast, D. alpha decreased for S. bungeana with grazing intensities. Our results strongly suggest that in grasslands, grazing intensity can lead to changes in the colonization of specific root fungal taxa, and these fungal changes would potentially feed back to plant performance depending on the abundance of host plants. Copyright © 2017 John Wiley & Sons, Ltd.

show abstract

“…We observed a decline in population size and recruitment rates over the study period. Other studies have shown that disease may reduce both seed quality in subsequent generations (Jarosz, Burdon & Muller ) and competitive ability in relation to other species (Paul & Ayres ; Paul ; Friess & Maillet ; Allan, van Ruijven & Crawley ). Although we do not have direct evidence of the effects of M. lini infection on seed quality or plant competitive ability, there is clearly potential for such disease effects to profoundly alter plant community structure (Borer et al .…”

Section: Discussionmentioning

confidence: 99%

“…Although we do not have direct evidence of the effects of M. lini infection on seed quality or plant competitive ability, there is clearly potential for such disease effects to profoundly alter plant community structure (Borer et al . ; Allan, van Ruijven & Crawley ). Notwithstanding these effects, it is most likely that the decline in the Kiandra L. marginale population was also strongly influenced by vegetational successional processes – increasing density of grass and herb cover and encroachment by a range of low shrubs (Leigh et al .…”

Section: Discussionmentioning

confidence: 99%

Local demographic and epidemiological patterns in theLinum marginale–Melampsora liniassociation: a multi‐year study

et al. 2017

View full text Add to dashboard Cite

Summary Many theoretical and empirical studies operate from an assumption that pathogens have a significant influence on the fecundity and life span of their host species. However, there are surprisingly little data investigating the long‐term fitness impacts and genetic consequences that arise from pathogen infection in natural populations. Here, we address this gap through the analysis of a dataset investigating the local population dynamics of a native host plant (Linum marginale) and an associated rust pathogen (Melampsora lini) across 12 years. To investigate patterns of disease prevalence and severity and track effects on host fecundity and demography, we conducted censuses on an annual basis at a single site. Annual M. lini infection prevalence ranged from 0% to 99%. Severe epidemics occurred in 3‐ to 4‐year cycles causing high overwintering mortality and subsequent changes in the relative abundance of different host phenotypes. Host population size oscillated in response to epidemics and declined towards the end of the observation period. Changes in host numbers were found to affect disease severity but not infection prevalence. Melampsora lini infection increased L. marginale fecundity; the infected plants produced threefold more seed capsules on average than uninfected plants (13·3 vs. 4·3 seed capsules per plant). To investigate how variation in environmental conditions affects epidemiology and host demography, we identified climatic factors affecting host growth, overwintering and disease severity. Winter (June) rainfall increased host overwintering success and summer (December) rainfall favoured host growth. The progress of M. lini disease epidemics benefited from optimal temperatures in February and suffered from rainfall in January. We further examined links between the genetic structure of the pathogen population and disease dynamics. There was a positive correlation between mean pathogen infectivity (as measured across a host differential set) and the severity of disease epidemics. Synthesis. Our results provide new insights into local drivers and consequences of pathogen epidemiology in natural populations. Melampsora lini infection can have profound consequences on the phenotype, demography and population structure of Linum marginale by increasing host fecundity, overwinter mortality and disease resistance.

show abstract

Foliar fungal pathogens and grassland biodiversity

Cited by 119 publications

References 78 publications

Evaluating the impacts of multiple generalist fungal pathogens on temperate tree seedling survival

Evaluating the impacts of multiple generalist fungal pathogens on temperate tree seedling survival

Grazing Intensity Affects Communities of Culturable Root‐Associated Fungi in a Semiarid Grassland of Northwest China

Local demographic and epidemiological patterns in theLinum marginale–Melampsora liniassociation: a multi‐year study

Contact Info

Product

Resources

About