a Holly P. Jones
A key question in ecology
and conservation biology is whether an ecosystem can recover to its original
state following a perturbation. In the case of perturbations caused by invasive
species, ecosystems may have been altered such that they jump to an alternate
state. Invasive species removal, then, may not be sufficient to restore
ecosystems back to their original states. In such cases, active restoration of
ecosystem function must be coupled with invasive species removal to
successfully restore systems. I am using the many and ongoing rodent
eradications on New Zealand offshore islands, and the relatively recent idea of
actively restoring seabird populations following rodent removal as a study
system to evaluate ecosystem resilience in the face of invasive species
removal.
I am using a 3-pronged approach to study island ecosystem
recovery following invasive rodent removal.
1) Natural
Experiment - I will use islands with different invasive rodent histories to do
a systematic replicated natural experiment evaluating ecosystem function on
islands: with invasive rodents, that have never had invasive rodents, with
invasive rodents eradicated, and with invasive rodents eradicated plus active
seabird restoration. I will take this one step further by conducting research
on multiple islands that have had differing times to recovery following rat
eradication (a chronosequence). This will help to
investigate whether islands recover on their own given time or whether they
entrain in an alternate, low-nutrient but rat-free state without subsequent seabird
restoration.
2) Experimental
Ecosystem Recovery - Since seabird restoration is still in its early stages on
my islands with seabird restoration, I will simulate seabird recovery using a
fertilization experiment. This will allow me to track recovery on a shorter
timescale than it takes seabirds to recover (often decades).
3) Insular Response Models - I will use the data I gather along with seabird time-activity budgets to model seabird nutrient input on islands. I will then use seabird population data to generate a population viability analysis for seabirds on seabird restoration islands. Finally, I will combine nutrient and seabird models to project both seabird and nutrient recovery into the future.
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Funding
Institutions
Yale Institute for Biospheric Studies
American
Philosophical Society Lewis and Clark Exploration Grant
Sophie
Danforth Conservation Biology Fund
Many thanks also to New
Zealand Department of Conservation, Ngati Koata, Ngati Toa,
Ngati
Kuia, Ngati
Hei, Ngati Whanaunga, Victoria
University Wellington, and Yale Earth Systems
Center for Stable Isotopic Studies.
Peer-reviewed Publications
Jones, Holly P., B. R. Tershy, E. S. Zavaleta, D. A. Croll, B. S. Keitt, and M.E. Finkelstein. (2008). Severity of the effects of invasive rats on
seabirds: A global review. Conservation
Biology 22(1): 16-26. large
cover image
Schmitz,
Oswald J., H. P. Jones and B. T. Barton (2007). Scavengers. Encyclopedia of
Ecology.
Jones, Holly P., R.W.
Henry III, G. R. Howald, B. R. Tershy,
and D. A. Croll (2005). Predation of artificial Xantus
Murrelet nests before and after black rat eradication.
Environmental Conservation 32(4): 320-325.