Nicholas J Kooyers

• PhD
• Professor (Assistant) at University of Louisiana at Lafayette

Herbaceous plant species have been the focus of extensive, long-term research into climate change responses, but there has been little effort to synthesize results and predicted outlooks from different model species. We summarize research on climate change responses for eight intensively-studied herbaceous plant species. We establish generalities a...

Projecting how a population will adapt to environmental changes requires a mechanistic understanding of the specific biotic and abiotic factors that impose selection on that population. In white clover (Trifolium repens), clines in an antiherbivore defense mechanism, hydrogen cyanide (HCN), form via variation in selection imposed by the environment...

Background and Aims Success during colonization likely depends on growing quickly and tolerating novel and stressful environmental conditions. However, rapid growth, stress avoidance, and stress tolerance are generally considered divergent physiological strategies. Methods We evaluate how white clover (Trifolium repens) has evolved to a divergent...

Climate change and the global spread of non-native species are two of the most significant threats to biodiversity and ecosystem function. Both these phenomena subject populations to novel conditions, either in space (species introductions) or in time (climate change), yet the role of adaptation in how populations respond to these rapid environment...

Background and Aims: Success during colonization likely depends on growing quickly and tolerating novel and stressful environmental conditions. However, rapid growth, stress avoidance, and stress tolerance are generally considered divergent physiological strategies. Methods: We evaluate how white clover (Trifolium repens) has evolved to a divergent...

Scientists must have an integrative understanding of ecology and evolution across spatial and temporal scales to predict how species will respond to global change. Although comprehensively investigating these processes in nature is challenging, the infrastructure and data from long-term ecological research networks can support cross-disciplinary in...

Premise Polypodium pellucidum , a fern endemic to the Hawaiian Islands, encompasses five ecologically and morphologically variable subspecies, suggesting a complex history involving both rapid divergence and rampant hybridization. Methods We employed a large target‐capture data set to investigate the evolution of genetic, morphological, and ecolog...

Urbanisation is occurring globally, leading to dramatic environmental changes that are altering the ecology and evolution of species. In particular, the expansion of human infrastructure and the loss and fragmentation of natural habitats in cities is predicted to increase genetic drift and reduce gene flow by reducing the size and connectivity of p...

Heat waves are becoming more frequent and intense with climate change, but the demographic and evolutionary consequences of heat waves are rarely investigated in herbaceous plant species. We examine the consequences of a short but extreme heat wave in Oregon populations of the common yellow monkeyflower ( Mimulus guttatus ) by leveraging a common g...

White clover (Trifolium repens L.; Fabaceae) is an important forage and cover crop in agricultural pastures around the world and is increasingly used in evolutionary ecology and genetics to understand the genetic basis of adaptation. Historically, improvements in white clover breeding practices and assessments of genetic variation in nature have be...

Premise of study: Annual plants often exhibit drought escape and avoidance strategies to cope with limited water availability. Determining the extent of variation and factors underlying evolution of divergent strategies is necessary for determining population responses to more frequent and severe droughts. Methods: We leverage five Mimulus gutta...

Background White clover (Trifolium repens L.; Fabaceae) is an important forage and cover crop in agricultural pastures around the world, and is increasingly used in evolutionary ecology and genetics to understand the genetic basis of adaptation. Historically, improvements in white clover breeding practices and assessments of genetic variation in na...

Heatwaves are becoming more frequent and intense with climate change, but the demographic and evolutionary consequences of heatwaves are rarely investigated in herbaceous plant species. We examine the consequences of a short but extreme heatwave in Oregon populations of the common yellow monkeyflower (Mimulus guttatus) by leveraging a common garden...

Although chemical defenses and herbivore pressure are widely established as key targets and agents of selection, their roles in local adaptation and determining potential evolutionary responses to changing climates are often neglected. Here, we explore fitness differences between 11 rangewide M. guttatus populations in a field common garden experim...

The extent to which species can adapt to spatiotemporal climatic variation in their native and introduced ranges remains unresolved. To address this, we examined how clines in cyanogenesis (HCN production—an antiherbivore defense associated with decreased tolerance to freezing) have shifted in response to climatic variation in space and time over a...

Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of hospital-associated urinary tract infections (UTI), especially in catheterized individuals. Despite being rare, MRSA UTI are prone to potentially life-threatening exacerbations such as bacteremia that can be refractory to routine antibiotic therapy. To delineat...

Genetic diversity becomes structured among populations over time due to genetic drift and divergent selection. Although population structure is often treated as a uniform underlying factor, recent resequencing studies of wild populations have demonstrated that diversity in many regions of the genome may be structured quite dissimilar to the genome‐...

• We examine the extent to which phylogenetic effects and ecology are associated with macroevolutionary patterns of phytochemical defense production across the Mimulus phylogeny. • We grew plants from 21 species representing the five major sections of the Mimulus phylogeny in a common garden to assess how the arsenals (NMDS groupings) and abundance...

Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of hospital-associated urinary tract infections, especially in catheterized individuals. Despite being rare, MRSA-UTI are prone to potentially life-threatening exacerbations such as bacteremia that can be refractory to routine antibiotic therapy. Hence, MRSA-UTI i...

Premise: Due to climate change, more frequent and intense periodic droughts are predicted to increasingly pose major challenges to the persistence of plant populations. When a severe drought occurs over a broad geographical region, independent responses by individual populations provide replicated natural experiments for examining the evolution of...

Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits i...

This article comments on: M. Bouzid, F. He, G. Schmitz, R. E. Häusler, A. P. M. Weber, T. Mettler-Altmann and J. de Meaux. 2019. Arabidopsis species deploy distinct strategies to cope with drought stress. Annals of Botany 124(1): 27–40.

While native populations are often adapted to historical biotic and abiotic conditions at their home site, populations from other locations in the range may be better adapted to current conditions due to changing climates or extreme conditions in a single year. We examine whether local populations of a widespread species maintain a relative advanta...

Premise of the Study The maintenance of adaptive polymorphisms within species requires fitness trade‐offs reflecting selection for each morph. Cyanogenesis, the ability to produce hydrogen cyanide (HCN) after tissue damage, occurs in >3000 plant species and exists as a discrete polymorphism in white clover. This polymorphism is spatially distribute...

Closely related species may evolve to coexist stably in sympatry through niche differentiation driven by in situ competition, a process termed character displacement. Alternatively, past evolution in allopatry may have already sufficiently reduced niche overlap to permit establishment in sympatry, a process called ecological sorting. The relative i...

The latitudinal herbivory defense hypothesis (LHDH) postulates that the prevalence of species interactions, including herbivory, is greater at lower latitudes, leading to selection for increased levels of plant defense. While latitudinal defense clines may be caused by spatial variation in herbivore pressure, optimal defense theory predicts that cl...

Examining how morphology, life history and physiology vary along environmental clines can reveal functional insight into adaptations to climate and thus inform predictions about evolutionary responses to global change. Widespread species occurring over latitudinal and altitudinal gradients in seasonal water availability are excellent systems for in...

Variation in cyanogenesis (hydrogen cyanide release following tissue damage) was first noted in populations of white clover more than a century ago, and subsequent decades of research have established this system as a classic example of an adaptive chemical defence polymorphism. Here, we document polymorphisms for cyanogenic components in several r...

Identifying the genetic basis of parallel phenotypic evolution provides insight into the process of adaptation and evolutionary constraint. White clover (Trifolium repens) has evolved climate-associated adaptive clines in cyanogenesis (the ability to produce hydrogen cyanide upon tissue damage) in several world regions where it has been introduced....

Adaptive differentiation between populations is often proposed to be the product of multiple interacting selective pressures, although empirical support for this is scarce. In white clover, populations show adaptive differentiation in frequencies of cyanogenesis, the ability to produce HCN after tissue damage. This polymorphism arises through indep...

The recurrent evolution of adaptive clines within a species can be used to elucidate the selective factors and genetic responses that underlie adaptation. White clover is polymorphic for cyanogenesis (HCN release with tissue damage), and climate-associated cyanogenesis clines have evolved throughout the native and introduced species range. This pol...

Background/Question/Methods Clines are the spatial manifestation of an ecological tradeoff, and are frequently used to understand how divergent selection pressures create adaptive divergence between populations. In white clover, clines in the polymorphic trait cyanogenesis, the ability to produce hydrogen cyanide after tissue damage, have formed...

Understanding the molecular evolution of genes that underlie intraspecific polymorphisms can provide insights into the process of adaptive evolution. For adaptive polymorphisms characterized by gene presence/absence (P/A) variation, underlying loci commonly show signatures of long-term balancing selection, with gene-presence and gene-absence allele...