[Lo-Feature] The May 1999 L&O Featured Article is Now Posted

[Everett Fee]

The first Featured Article for Limnology and Oceanography is now 
available! 

		The May 1999 L&O Featured Article

Hairston et al. (1999) have reconstruct the invasion, establishment, and 
subsequent disappearance of a zooplankton species, Daphnia exilis, 
from Onondaga Lake in New York. Among other things, this paper 
illustrates how human disturbance of an aquatic system can set the 
stage for invasion of exotics, and that a reversal of that disturbance can 
result in a reversal of that invasion. 

The article is located at the web address 
http://aslo.org/lo/toc/vol_44/issue_3/0477.pdf 

Instructions for reading PDF-format files are located on the L&O main 
web page (http://aslo.org/help/loonline.html) 

Introductory comments by Alan J. Tessier (L&O Associate Editor) 

Invasions by exotic species into aquatic systems are, unfortunately, all 
too common. The Great Lakes alone have been successful invaded by 
over 130 species in the past 100 years and the frequency of new 
invasions continues to rise. Although native to North America, Daphnia 
exilis is not known to occur east of the Mississippi River, and not within 
a 1000 km of Onondaga Lake. However, Waterman (1971) did report it s 
presence in Onondaga Lake in 1969, a report that was later viewed as a 
misidentification. Hairston et al. used paleolimnological techniques to 
document that D. exilis was, indeed, present in the lake at the time 
Waterman reported them. Further, they show that the first invasion of D. 
exilis, in the 1920s, failed, but then a second invasion occurred in the 
1940s. This second invasion also failed by the early 1980s and the 
species has not since reappeared. 

A unique aspect of this paper is that Hairston et al. combine 
paleolimnological techniques with a study of the viability of D. exilis 
resting eggs from the entire sediment record of the invasion, and then 
use protein electrophoresis to characterize the genetic structure of the 
population. This genetic information is compared (by simulation) to 
similar data from populations of this species in its known range, to 
conclude that a single founding event (likely a single clone) established 
the Onondaga population. The re-invasion in the 1940s can be explained 
by dispersal in time (resting eggs) and, more interestingly, viable resting 
eggs still remain within the sediment at a depth easily exposed by any 
boat anchor. In the words of one reviewer "This is an excellent, 
fascinating study, uniquely combining paleoecology, population 
genetics and population simulations to address invasion of an exotic 
species." 

Reconstruction of ecological and macro-evolutionary change from a 
fossil record is hardly new, but resting eggs are not exactly fossils! I am 
aware of only two other studies that combine paleoecology with 
hatching of dormant propagules to characterize representatives from 
historic populations: Weider et al. (1997) and Kerfoot et al. (in press). 
What future ecological and evolutionary questions will the sediment 
record of viable but dormant propagules be used to answer? Do we need 
a new name to describe this research? W. C. Kerfoot (pers. comm) has 
suggested one = resurrection ecology. 

References: 

Hairston, N. G., L. J. Perry, A. J. Bohonak, M. Q. Fellows and C. M. 
Kearns. 1999. Population biology of a failed invasion: Paleolimnology of 
Daphnia exilis in upstate New York. Limnology and Oceanography 44: 
477-486. 

Kerfoot, W. C., John A. Robbins, and Lawrence J. Weider. 1999. A new 
approach to historical reconstruction: Combining descriptive and 
experimental paleolimnology. Limnology and Oceanography. In press. 

Waterman, G. 1971. Onondaga Lake zooplankton. Onondaga Lake 
study project No. 11060, FAE 4/71, p. 3610384. Water Quality Office, 
USEPA. 

Weider, L. J., W. Lampert, M. Wessels, J. K. Colbourne and P. 
Limburg. 1997. Long-term genetic shifts in a microcrustacean egg bank
associated with anthropogenic changes in the Lake Constance 
ecosystem. Proc. R. Soc. Lond. B 264: 1613-1618. 

-Best regards,
Everett
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Everett Fee=20
Editor-in-Chief, Limnology & Oceanography=20
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Canmore, Alberta  T1W 1H5  CANADA=20
office: 403/609-2456, fax: 403/609-2400
<lo-editor@aslo.org>=20
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