Profundal-Pelagic Macrocrustacean Abundance in Boreal Lakes Before and After Experimental Clearcut Logging

Robert France

doi:10.5755/j01.erem.56.2.272

Abstract

A sampling program of 9 years revealed that the opossum shrimp Mysis relicta and the amphipod Diporeia hoyi were present in three boreal lakes in northwestern Ontario, Canada regardless of whether watershed forests were left completely intact, left as only a narrow buffer strip, or were nearly completely removed through experimental clearcutting. In fact, Diporeia were actually found to be more abundant in all lakes following logging. And the decline in Mysis abundance observed in one of the lakes occurred well before the initiation of timber removal. Consequently, it appears that these keystone, glacial-relic species of macrocrustaceans are not negatively impacted by clearcutting. This is in direct contrast to the hyper-sensitivity and extirpation of these same species which has been previously demonstrated in acidifying boreal lakes.

Highlights

With an annual removal rate of nearly 1%, the scale of timber harvesting in the boreal forest of Canada, mostly through clearcutting operations, is truly enormous (Perera et al 2000)
The purpose of the present study was to provide the first documentation of the abundance response of two important glacial relic species: the opossum shrimp Mysis relicta and the amphipod Diporeia hoyi to experimental clearcut logging around boreal lakes
During the experimental timber harvest, 5 km of logging roads were constructed in the watersheds of Lake 39 (L39) and L42 and 2 km of roads were constructed in the watershed of L26

Summary

Introduction

With an annual removal rate of nearly 1%, the scale of timber harvesting in the boreal forest of Canada, mostly through clearcutting operations, is truly enormous (Perera et al 2000). The great majority of research on the influences of logging on aquatic communities comes from studies on small streams, often conducted in mountainous regions and which may have only limited applicability to situations in the boreal forest (Carignan & Steedman 2000, Pinel-Alloul et al 2002). Studies of the implications of logging on the limnology and aquatic ecology of boreal lakes are relatively infrequent (Steedman et al 2004). Alterations in the abundance or biology of fishes in boreal lakes due to watershed or riparian clearcutting seem to be relatively minor or nonexistent (Berube & Levesque 1998, Rask et al 1998, St. Onge & Magnan 2000, Tonn et al 2003, Bertolo and Magnan 2006).

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