Jill Hamilton

• PhD
• Professor (Associate) at Pennsylvania State University

Tree species are often locally adapted to their environments, but the extent to which environmental adaptation contributes to incipient speciation is unclear. One of the rarest pines in the world, Torrey pine (Pinus torreyana Parry), persists naturally across one island and one mainland population in southern California. The two populations are mor...

Genetic diversity is critical for adaptation in response to changing environments and provides a valuable metric for predicting species’ extinction risk. The International Union for Conservation of Nature (IUCN) and broader scientific community have acknowledged that genetic diversity is a critical component to biodiversity conservation. However, t...

Understanding the evolutionary processes underlying range‐wide genomic variation is critical to designing effective conservation and restoration strategies. Evaluating the influence of connectivity, demographic change and environmental adaptation for threatened species can be invaluable to proactive conservation of evolutionary potential. In this s...

Understanding the evolutionary processes underlying range-wide genomic variation is critical to designing effective conservation and restoration strategies. Evaluating the influence of connectivity, demographic change, and environmental adaptation for threatened species can be invaluable to proactive conservation of evolutionary potential. In this...

Local species-climate relationships are often considered in restoration management. However, as climate change disrupts species-climate relationships, identifying factors that influence habitat suitability now and into the future for individual species, functional groups, and communities will be increasingly important for restoration. This involves...

Population demographic changes, alongside landscape, geographic and climate heterogeneity, can influence the timing, stability and extent of introgression where species hybridise. Thus, quantifying interactions across diverged lineages, and the relative contributions of interspecific genetic exchange and selection to divergence at the genome‐wide l...

Genetic diversity is critical for adaptation in response to changing environments and provides a valuable metric for predicting species’ extinction risk. The International Union for Conservation of Nature (IUCN) and broader scientific community have acknowledged that genetic diversity is a critical component to biodiversity conservation. However, t...

13 Understanding the genomic mechanisms contributing to speciation requires studies of taxa that 14 are in the early stages of divergence, before complete reproductive isolation has evolved. One 15 of the rarest pines in the world, Torrey Pine (Pinus torreyana Parry), persists naturally across 16 one island and one mainland population in southern C...

Understanding dispersal potential, or the probability a species will move a given distance, under different environmental conditions is essential to predicting species' ability to move across the landscape and track shifting ecological niches. Two important drivers of dispersal ability are climatic differences and variations in local habitat type....

Restoration advocates for the use of local seed in restoration, but theory suggests that diverse seed sources may enhance genetic diversity and longer term evolutionary potential within restored communities. However, few empirical studies have evaluated whether species and genetic diversity within species impacts plant community composition followi...

Changes in telomere length are increasingly used to indicate species' response to environmental stress across diverse taxa. Despite this broad use, few studies have explored telomere length in plants. Thus, evaluation of new approaches for measuring telomeres in plants is needed. Rapid advances in sequencing approaches and bioinformatic tools now a...

Background and aims: The ability of plants to track shifting fitness optima is crucial within the context of global change, where increasing environmental extremes may have dramatic consequences to life history, fitness, and ultimately population persistence. However, tracking changing conditions relies on the relationship between genetic and envi...

Quantifying the mechanisms underlying hybrid zone formation requires an evaluation of both neutral and nonneutral evolutionary processes. Population demographic changes, alongside landscape heterogeneity and climate adaptation, can influence the timing, stability, and extent of introgression where species hybridize. Thus, quantifying interactions a...

Changes in telomere length are increasingly used to indicate species’ response to environmental stress across diverse taxa. Despite this broad use, few studies have explored telomere length in plants. However, rapid advances in sequencing approaches and bioinformatic tools now allow estimation of telomere length using whole genome sequencing (WGS)...

Landscape transcriptomics is an emerging field studying how genome-wide expression patterns reflect dynamic landscape-scale environmental drivers, including habitat, weather, climate, and contaminants, and the subsequent effects on organismal function. This field is benefitting from advancing and increasingly accessible molecular technologies, whic...

Premise: How the environment influences the distribution of trait variation across a species' range has important implications for seed transfer during restoration. Evolution across environments could influence fitness when individuals are transferred into new environments. Here, we evaluate the role the environment has had on the distribution of...

Understanding the contribution of neutral and adaptive evolutionary processes to population differentiation is often necessary for better informed management and conservation of rare species. In this study, we focused on Pinus torreyana Parry (Torrey pine), one of the world’s rarest pines, endemic to one island and one mainland population in Califo...

Purpose of Review Assisted migration is increasingly proposed as a proactive management strategy to mitigate the consequences of maladaptation predicted under climate change. Exploring the social and academic structure of the field, its research gaps, and future research directions can help further the understanding and facilitate the implementatio...

A hundred years after Turesson first clearly described how locally adaptive variation is distributed within species, plant biologists are making major breakthroughs in our understanding of mechanisms underlying adaptation from local populations to the scale of continents. Although the genetics of local adaptation has typically been studied in small...

Premise of the Study Understanding how environment influences the distribution of trait variation across a species’ range has important implications for seed transfer during restoration. Heritable genetic differences associated with environment could impact fitness when transferred into new environments. Here, we test the degree to which the enviro...

Restoration often advocates for the use of local seed in restoration, however increasingly new strategies have been proposed to incorporate diverse sources to maintain evolutionary potential within seed mixes. Increasing seed sources per species within a seed mix should increase genetic variation, however, few empirical studies have evaluated how s...

The ability of plants to track shifting fitness optima is crucial within the context of global change, where increasing environmental extremes may have dramatic consequences to life history, fitness, and ultimately species persistence. However, to track changing conditions relies upon the complex relationship between genetic and environmental varia...

Understanding the within- and among-population distribution of trait variation within seed collections may provide a means to approximate standing genetic variation and inform plant conservation. This study aimed to estimate population- and family-level seed trait variability for existing seed collections of Torrey pine (Pinus torreyana), and to us...

Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long-standing tools available to manage genetics - the pedigree - has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput se...

Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long‐standing tools available to manage genetics ‐ the pedigree ‐ has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput se...

Globally imperiled ecosystems often depend upon collection, propagation, and storage of seed material for use in restoration. However, during the restoration process demographic changes, population bottlenecks, and selection can alter the genetic composition of seed material, with potential impacts for restoration success. The evolutionary outcomes...

Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long-standing tools available to manage genetics-the pedigree-has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput sequen...

Understanding the contribution of neutral and adaptive evolutionary processes to population differences is often necessary for better informed management and conservation of rare species. In this study, we focused on Pinus torreyana Parry (Torrey pine), one of the world's rarest pines, endemic to one island and one mainland population in California...

Globally imperiled ecosystems often depend upon collection, propagation, and storage of seed material for use in restoration. However, during the restoration process demographic changes, population bottlenecks, and selection can alter the genetic composition of seed material, with potential impacts for restoration success. The evolutionary outcomes...

PREMISE Optimizing the amount of genetic diversity captured in seed collections is a long-standing objective of ex situ conservation. Particularly for rare species where limited genetic information is available, it poses a significant challenge. However, understanding the within and among population distribution of trait variation within seed colle...

Understanding the evolution of dispersal under changing global environments is essential to predicting a species ability to track shifting ecological niches. Two important, but anthropogenically altered, sources of selection on dispersal are climate and habitat continuity. Despite the likelihood these global drivers of selection act simultaneously...

AoBP preprint of special issue on journal's website. Yoko et al, (2020). The importance of quantitative trait differentiation in restoration: landscape heterogeneity and functional traits inform seed transfer guidelines.

Maintenance of biodiversity, through seed banks and botanical gardens where the wealth of species genetic variation may be preserved ex situ, is a major goal of conservation. However, challenges can persist in optimizing ex situ collections where trade-offs exist between expense, effort, and conserving species evolutionary potential, particularly w...

Ecological restoration projects that include reforestation require that land managers select appropriate source of seeds for long-term persistence. In California, the standard approach for making this choice is based on seed zone and elevational band, both geographically-based measures. However, given the pace of contemporary climate change, popula...

Understanding the processes underlying speciation has long been a challenge to evolutionary biologists. This spurs from difficulties teasing apart the various mechanisms that contribute to the evolution of barriers to reproduction. The study by Rafati et al. (2018) in this issue of Molecular Ecology combines spatially explicit whole‐genome resequen...

Rare species present a challenge under changing environmental conditions as the genetic consequences of rarity may limit species ability to adapt to environmental change. To evaluate the evolutionary potential of a rare species, we assessed variation in traits important to plant fitness using multigenerational common garden experiments. Torrey pine...

Forest tree hybrid zones provide a wealth of novel genetic variation that can be harnessed to safeguard populations in changing climates. In the past 30 years, natural and artificial forest hybrid zones have facilitated significant contributions to selective breeding programs, conservation, and our understanding of the evolutionary processes and me...

Timely responses to environmental cues enable the synchronization of phenological life-history transitions essential for the health and survival of north-temperate and boreal tree species. While photoperiodic cues will remain persistent under climate change, temperature cues may vary, contributing to possible asynchrony in signals influencing devel...

Understanding the genetic mechanisms that contribute to range expansion and colonization success within novel environments is important for both invasion biology and predicting species-level responses to changing environments. If populations are adapted to local climates across a species' native range, then climate matching may predict which genoty...

In the Canadian Rocky Mountains, the gray wolf (Canis lupus) has experienced range contractions and expansions, which can greatly affect pack stability as well as population structure. In addition, this area has a highly heterogeneous landscape that may form barriers to dispersal. To understand factors affecting pack structure and large-scale gene...

Although restoration biology is commonly depicted as an ecological field, it is in many ways an evolutionary science. When we manage habitats to enhance or impair the performance of target species we are implicitly managing adaptation. In the past, restoration practitioners have emphasized preserving genetic diversity as a resource for future evolu...

Current rates of climate change require organisms to respond through migration, phenotypic plasticity, or genetic changes via adaptation. Here we focus on questions regarding species' and populations' ability to respond to climate change through adaptation. Specifically, the role adaptive introgression, movement of genetic material from the genome...

Understanding the genetic mechanisms that contribute to range expansion and colonization success within novel environments is important for both invasion biology and predicting species-level responses to changing environments. If populations are adapted to local climate across a species’ native range, then climate matching may predict which genotyp...

Hybridization is common for many forest trees, where weak barriers to reproduction obscure species boundaries. We characterized the genomic structure of Picea populations comprising three species spanning two well-known contact zones, the Picea sitchensis×Picea glauca and the P. engelmannii×P. glauca hybrid zones, using a set of 71 candidate-gene s...

Background/Question/Methods Timely responses to environmental cues enable synchronization of life history transitions essential for health and survival of northern boreal tree species. The activity-dormancy transition influences bud dormancy and the inability of the meristem to resume growth, an important adaptation within forest trees. Both phot...

Premise of the study: Historic colonization and contemporary evolutionary processes contribute to patterns of genetic variation and differentiation among populations. However, separating the respective influences of these processes remains a challenge, particularly for natural hybrid zones, where standing genetic variation may result from evolutio...

Climate change research is an interdisciplinary field, and understanding its social, political, and environmental implications requires integration across fields of research where different tools may be used to address common concerns [Baerwald, 2010]. One of the many advantages of interdisciplinary approaches is that they open communication betwee...

Differential patterns of introgression between species across ecological gradients provide a fine‐scale depiction of extrinsic and intrinsic factors that contribute to the maintenance of species barriers and adaptation across heterogeneous environments. Introgression was examined for 721 individuals collected from the ecological transition zone spa...

Interspecific hybridization may enhance the capacity of populations to adapt to changing environments, and has practical implications for reforestation. We use genome-wide estimates of admixture and phenotypic traits for trees in a common garden to examine the extent and direction of gene flow across a Picea hybrid zone, testing assumptions of the...

Species may often exhibit geographic variation in population genetic structure due to contemporary and historical variation in population size and gene flow. Here, we test the predictions that populations on the margins of a species' distribution contain less genetic variation and are more differentiated than populations towards the core of the ran...