The introduction of non-native species can have substantial effects on native communities. In marine habitats, the frequency of species introductions, both human-mediated and ‘naturally occurring’ (i.e. range shifts or expansions due to changes in local/regional environmental conditions), appears to be increasing.
I’m interested in trying to understand what makes some species successful invaders of novel habitats by quantifying demographic rates and life history processes of an ecologically significant and highly invasive bryozoan (Membranipora membranacea) in the northwest Atlantic. My research is focused on 1) identifying life history characteristics that differ between native and invasive populations of M. membranacea and how these differences may have contributed to both the initial invasion success and the continued persistence of M. membranacea in the northwest Atlantic, 2) quantifying the effects of intrinsic (organismal) and extrinsic (environmental) factors on demographic rates of M. membranacea, and 3) incorporating data on life history strategies (e.g. larval settlement behavior) and demographic rates (e.g. fecundity, mortality) into a population model for M. membranacea in its invaded habitat that can be used to project the M. membranacea population under future climate scenarios to more accurate predict the long-term effects the invasion by M. membranacea may have on subtidal ecosystems in the northwest Atlantic.
The goal of my research is to provide insight into the life-history characteristics of invasive species, and the environmental conditions of invaded communities, that can facilitate successful species invasions, in hopes of mitigating potentially dramatic changes to marine communities as a result of future species introductions.
Scholarships and Awards
Level 2 Izaak Walton Killam Predoctoral Scholarship (2015-2018)
NSERC Postgraduate Scholarship – Doctoral Program (2015-2018)
Nova Scotia Research and Innovation Graduate Scholarship – Doctoral Level (2014-2018)
NSERC Undergraduate Student Research Award, Queen’s University (2011)
NSERC Undergraduate Student Research Award, Queen’s University (2010)
Denley D, Metaxas A (2017) Lack of substrate specificity contributes to invasion success and persistence of Membranipora membranacea in the northwest Atlantic. Marine Ecology Progress Series. doi:10.3354/meps12287
Denley D, Metaxas A (2017) Effects of intrinsic and extrinsic factors on reproduction of an ecologically significant invasive bryozoan: implications for invasion success. Marine Biology 164:145. doi:10.1007/s00227-017-3172-3
Denley D, Metaxas A (2016) Quantifying mortality of modular organisms: a comparison of partial and whole colony mortality in a colonial bryozoan. Ecosphere 7(10):e01483. 10.1002/ecs2.1483
Denley D, Metaxas A (2015) Recovery capacity of the invasive colonial bryozoan Membranipora membranacea (Linnaeus) from damage: effects of temperature, location, and magnitude of damage. Marine Biology 162: 1769-1778
Denley D, Metaxas A, and Short J (2014) Selective settlement by larvae of Membranipora membranacea and Electra pilosa (Ectoprocta) along kelp blades in Nova Scotia, Canada. Aquatic Biology 21: 47-56
Denley, D. Metaxas, A. New house, new rules: life-history strategies can enhance invasion success of introduced species. Victoria, BC. Canadian Society for Ecology and Evolution meeting. May, 2017
Denley, D., Metaxas, A. New house, new rules: variation in life-history strategies can enhance invasion success of introduced species. Halifax, NS. Conference of Dalhousie Oceanography Graduate Students. March, 2017
Denley, D., Metaxas, A. Mortality of the invasive, colonial bryozoan Membranipora membranacea in the NW Atlantic: the effect of temperature on seasonal colony senescence. Portland, Maine. Benthic Ecology Meeting 2016. March 2016
Denley, D., Metaxas, A. (2015) The relative effects of intrinsic and external factors on mortality of the invasive colonial bryozoan Membranipora membranacea. St. Andrews, NB. Atlantic Canada Coastal and Estuarine Science Society
Denley, D., Metaxas, A. (2014) Measuring mortality of the colonial invasive bryozoan Membranipora membranacea: the effect of temperature on partial colony mortality and regeneration. Halifax, NS. Atlantic Canada Coastal and Estuarine Science Society
Denley, D., Metaxas, A. (2014) Quantifying mortality of the colonial invasive bryozoan Membranipora membranacea: the effect of temperature on colony senescence and regeneration. Jacksonville, FL. Benthic Ecology Meeting
Denley, D., Metaxas, A. Quantifying population dynamics of the invasive bryozoan Membranipora membranacea in the northwest Atlantic: seasonal patterns in reproduction and fecundity. Lawrencetown, NS. Atlantic Canada Coastal and Estuarine Science Society. May, 2013
Denley, D., Metaxas, A. Quantifying population dynamics of the invasive bryozoan Membranipora membranacea in the northwest Atlantic. Halifax, NS. Conference of Dalhousie Oceanography Graduate Students. March, 2013
Denley, D., Eckert, C. Maintenance of an ecologically significant polymorphism in the coastal dune plant Camissoniopsis cheiranthifolia. Toronto, ON. Ontario Ecology, Ethology, and Evolution Colloquium. May, 2011
Denley, D. (2015) The regenerative capacity of colonial organisms: an age-old dilemma – Estimating mortality of an invasive bryozoan that is capable of rapid growth and regeneration. Current Tides, Dalhousie Oceanography Research Magazine 2: 16-19