Serpentine soil, which is naturally high in heavy metal content and has low calcium to magnesium ratios, comprises a difficult environment for most plants. An impressive number of species are endemic to serpentine, and a wide range of non-endemic plant taxa have been shown to be locally adapted to these soils. Locating genomic polymorphisms which are differentiated between serpentine and non-se...

Multiple introductions can play a prominent role in explaining the success of biological invasions. One often cited mechanism is that multiple introductions of invasive species prevent genetic bottlenecks by parallel introductions of several distinct genotypes that, in turn, provide heritable variation necessary for local adaptation. Here, we show that the invasion of Aegilops triuncialis into ...

Serpentine soils are edaphically stressful environments that host many endemic plant species. In particular, serpentine soils are high in several heavy metals (e.g. nickel, cobalt and chromium) and these high heavy metal concentrations are thought, in part, to lead to varying levels of plant adaptation and soil affinities (i.e. endemic vs. non-endemic plant species). It is unclear, however, whe...

I present the results of a culture-independent survey of soil bacterial communities from serpentine soils and adjacent nonserpentine comparator soils using a variety of newly developed phylogenetically based statistical tools. The study design included site-based replication of the serpentine-to-nonserpentine community comparison over a regional scale ( approximately 100 km) in Northern Califor...

Although plant adaptation to serpentine soils has been studied for several decades, the mechanisms of plant adaptation to edaphic extremes are still poorly understood. Arbuscular mycorrhizal fungi (AMF) are common root symbionts that can increase the plant hosts' establishment and growth in stressful environments. However, little is known about the role plant-AMF interactions play in plant adap...

Plant soil specialists contribute greatly to global diversity; however, the ecoevolutionary forces responsible for generating this diversity are poorly understood. We integrate molecular phylogenies with descriptive and experimental ecological data, creating a powerful framework with which to elucidate forces driving soil specialization. Hypotheses explaining edaphic specialization have histori...

Habitat specialization plays an important role in the creation and loss of biodiversity over ecological and evolutionary time scales. In California, serpentine soils have a distinctive flora, with 246 serpentine habitat specialists (i.e., endemics). Using molecular phylogenies for 23 genera containing 784 taxa and 51 endemics, we infer few transitions out of the endemic state, which is shown by...

Plants on serpentine soils provide extreme examples of adaptation to environment, and thus offer excellent models for the study of evolution at the molecular and genomic level. Serpentine outcrops are derived from ultramafic rock and have extremely low levels of essential plant nutrients (e.g., N, P, K, and Ca), as well as toxic levels of heavy metals (e.g., Ni, Cr, and Co) and low moisture ava...

Nyberg Berglund, A.-B. 2005. Postglacial colonization and parallel evolution of metal tolerance in the polyploid Cerastium alpinum. Doctoral dissertation. ISSN 1652-6880, ISBN 91-576-6964-3. The Fennoscandian flora is characterized by a high frequency of polyploids, probably because they were more successful than diploid plants in colonizing after the last Ice Age. The first postglacial coloniz...