Tyler Smith bio photo

Tyler Smith

Plant taxonomist
Adjunct professor
Field botanist

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Research

Overview

Plant Taxonomy

My primary research focus is species-level taxonomy, particularly in native crops and wild crop relatives. This work typically begins by delineating discrete groups, using a combination of morphometric and genetic data. This stems from my background as a field botanist: I am fascinated by plant diversity, and want to learn to recognize plant species as discrete, cohesive units. This assumes that species are discrete, cohesive units, an assumption that is not always met!

Once we have some idea of the species at hand, we can start to ask meatier evolutionary and ecological questions. I am interested in the relationship between speciation and niche evolution. I use a combination of field data and ecological niche modeling to quantify the ecology of species. Evaluation of this data in a phylogenetic framework is key to understanding how taxonomic diversity and ecological diversity are related.

Plant Conservation

I am also interested in the conservation of rare and endangered species. I have completed a number of COSEWIC species assessments, and prepared the recovery plan for Trichophorum planifolium, a woodland sedge that is endangered in Canada.

Current Projects

Conservation genetics of the Few-Flowered Clubrush, Trichophorum planifolium

Trichophorum planifolium persists in a single location in Canada, in the nature sanctuaries of Royal Botanical Gardens in Hamilton, Ontario. A second population in the Rouge Valley in Toronto may be extirpated. It is listed as an endangered species in Canada.

One of the concerns raised in the recovery strategy for this species is that this isolated northern population may be limited by low genetic diversity. To address this concern, we are quantifying the genetics of this population, as well as populations from across the range of the species in the eastern United States.

We are also analyzing habitat data from these field locations, and using this information, in combination with niche models, to identify priority habitat for potential reintroduction of this species in the Rouge Valley.

This is an MSc project for my student Victoria Nowell. It is funded by the Environment Canada’s Interdepartmental Recovery Fund, the Ontario Ministry of Natural Resources, with additional student support from NSERC and Carleton University.

Highbush blackberries, Rubus section Canadenses et al.

Collecting blackberry canes in Algonquin Provincial Park

Rubus is a taxonomic disaster. The blackberries (subgenus Eubatus) present a special problem. This group combines apomixis (clonal seed production), hybridization, and polyploidy. The result is incredible morphological variation that appears to be segregated among discrete species at the local level, but forms complex gradients across the continent.

The taxonomic response to Rubus has varied from excessive lumping, reducing the blackberries to less than 10 species in northeastern North America; to exuberant splitting, with several hundred named species. Neither approach is realistic, but the challenges posed by this group have precluded a better treatment so far.

The first phase of my work is collecting representative samples of highbush blackberries from across the northeast. I am using a combination of DNA fingerprinting (AFLPs and microsatellites) and morphometrics to complete a first-pass at sorting these plants into discrete groups. Once that’s done, I will be able to follow up with more detailed work to assess hybridization, polyploidy and reticulate evolution among species (or microspecies, as the case may be).

This project was funded by an AAFC Agriflex grant.

Small-fruited cranberries, Vaccinium oxycoccos

Vaccinium oxycoccos (tetraploid) flower

The small-fruited cranberry, Vaccinium oxycoccos, is a circumboreal species found in northern peatlands. The diploid cytotype can hybridize with the commercial large-fruited cranberry (Vaccinium macrocarpon), and may be a valuable resource for future breeding efforts. There are also polyploid cytotypes of Vaccinium oxycoccos. Botanists in Europe and northern North America have recognized the diploids as a species distinct from the polyploids, V. microcarpum, but the recent Flora of North America treatment of the group lumped all the cytotypes together as a single species.

I am interested in recent European work that shows that there is indeed a distinct morphological difference between diploid and polyploid plants. If this holds for North American plants, it will support recognizing the diploids as a distinct species. In the process of evaluating this hypothesis, I am building genotype, morphometric, and flow cytometry data sets. These tools will allow me to further explore the genetic relationship between diploid and polyploid V. oxycoccos, the clonal structure of their populations, and their evolutionary connection to V. macrocarpon.

This project was funded by an AAFC Agriflex grant.

Past Projects

Environmental Geometry and Emergent Properties of Ecological Communities

My post-doctoral research was an investigation of spatial aspects of plant community structure. Specifically, I was looking at how the spatial arrangement of the landscape influenced community richness and diversity, and how well our existing statistical tools performed in assessing these parameters.

Species limits and niche evolution in Carex section Porocystis

A Carex bushii x swanii hybrid

For my dissertation research, I examined the relationship between taxonomic diversity and ecological diversity in Carex section Porocystis. This involved conducting field surveys for globally rare species, resolving species boundaries, and assessing niche divergence.

In service of this project, I assessed the taxonomic issues with AFLP genotypes, restriction fragments (CAPS), and morphometrics. For the ecological issues, I combined ecological niche modeling (Maxent) with multivariate analysis of field data.