Research

Seed Dispersal

A focus of much of my current research has been on the dispersal of aquatic plant seeds, particularly by aquatic turtles. Seed dispersal is important for aquatic macrophytes but utilizing water (hydrochory) or fishes (ichthyochory) alone can be very limiting. Dispersal using aquatic turtles (chelonochory), which are often abundant and highly motile, can be very effective for within and between pond dispersal. My work has examined the role of Eastern painted turtles as seed vectors in both local ponds and rivers.

Padgett, D.J., A. Gouthro, M. Adams, T. Surasinghe. 2022. Silky dogwood (Swida
amomum) seed dispersal by freshwater turtles. Amer. J. Botany 109: 1508-1514.
Padgett, D.J., S. Quirk, M. Joyal, T. Surasinghe. 2019. Egestion of plant propagules by turtles in a small Massachusetts river. J. Natural History 53: 2011-2021.
Padgett, D.J., M. Joyal, S. Quirk, M. Laubi, T. Surasinghe. 2018. Evidence of aquatic plant seed dispersal by eastern painted turtles (Chrysemys picta picta) in
Massachusetts, USA. Aquatic Botany 149: 40-45.
Padgett, D.J., J.J. Carboni, and D.J. Schepis. 2010. The dietary composition of
eastern painted turtles (Chrysemys picta picta) with special reference to the
seeds of aquatic macrophytes. Northeastern Naturalist 17:305-312.

Rare Plants

I have always found imperiled species to be interesting in terms of how they cope and what may be the causative factors behind their rarity. I have researched rare plant species in New England as well as an endangered aquatic plant in Japan.

Padgett, D.J., S.M. McIntyre, T. Surasinghe. 2019. Reproductive aspects of
  Rhododendron maximum (Ericaceae) in Auburn, MA. Rhodora 121: 213-218.
Padgett, D.J., L. Cook, L. Horky, J. Noris and K. Vale. 2004. Seed production and
  germination in Long’s Bittercress (Cardamine longii) of Massachusetts.
  Northeastern Naturalist 11: 49-56.
Padgett, D.J., L. Horky, and M. Shimoda. 2002. Seed production and germination in
  endangered Nuphar (Nymphaeaceae) of western Japan. Journal of Phytogeography
and Taxonomy 50: 35-40.
Padgett, D.J., M. Shimoda, L. Horky, and D.H. Les. 2002. Natural hybridization and
  the imperiled Nuphar of western Japan. Aquatic Botany 72: 161-174.

Invasion Ecology

The invasion of non-native habitats by alien species has interested me since some of the worst documented cases of invasions have been aquatic plants. My research has documented the invasions of non-native plant species and has recently broadened to include non-native turtles (Red-eared sliders) and bivalves (Asian clams)

Padgett, D.J., J.E. Mendell, C. Ricardo Carbonell. 2021. An established Nuphar
advena (Nymphaeaceae) in Massachusetts. Rhodora 123: 360-362.
Padgett, D.J. and K. Frost. 2020. Butomus umbellatus (Butomaceae) established in Massachusetts. Rhodora 122: 45-47.
Padgett, D.J. and S.G. Smith. 2016. On the introduction of Bolboschoenus
glaucus (Cyperaceae) into southern New Hampshire. Rhodora 118: 227-228.
Padgett, D. J. and G. E. Crow. 1993. Some unwelcome additions to the flora
of New Hampshire. Rhodora 95: 348-351.

Systematics

Understanding the evolution of plants always serves as the foundation of my research. My taxonomic interests lie primarily within the genus Nuphar and its relatives in the Nymphaeales. My work has reconstructed evolutionary histories, devised classifications reflective of these phylogenies, and investigated natural hybridization, using both morphometric and molecular data.

Padgett, D.J. 2007. A monograph of Nuphar (Nymphaeaceae). Rhodora
  109: 1-95.
Padgett, D.J. 2003. Phenetic studies in Nuphar Sm. (Nymphaeaceae):
  variation in sect. Nuphar. Plant Systematics and Evolution 239: 187-197.
Padgett, D.J. 1998. Phenetic distinction between the dwarf yellow water-
  lilies: Nuphar microphylla and N. pumila (Nymphaeaceae). Can. J. Bot.
  76: 1755-1762.
Padgett, D.J., D.H. Les and G.E. Crow. 1998. Evidence for the hybrid origin
  of Nuphar × rubrodisca (Nymphaeaceae). Amer. J. Bot. 85: 1468-1476.