Woodland caribou population decline in Alberta: fact or fiction?

Corey J.A Bradshaw,Daryll M Hebert

doi:10.7557/2.16.4.1246

Abstract

We re-assessed the view of a major woodland caribou (Rangifer tarandus caribou) population decline in Alberta. Several historical publications and provincial documents refer to this drastic decline as the major premise for the designation of Alberta's woodland caribou an endangered species. In the past, wildlife management and inventory techniques were speculative and limited by a lack of technology, access and funding. The accepted trend of the decline is based on many speculations, opinions and misinterpretation of data and is unsubstantiated. Many aerial surveys failed to reduce variance and did not estimate sightability. Most surveys have underestimated numbers and contributed unreliable data to support a decline. Through forest fire protection and the presence of extensive wetlands, the majority of potential caribou habitat still exists. Recreational and aboriginal subsistence hunting does not appear to have contributed greatly to mortality, although data are insufficient for reliable conclusions. Wolf (Canis lupus), population fluctuations are inconclusive and do not provide adequate information on which to base prey population trends. The incidence of documented infection by parasites in Alberta is low and likely unimportant as a cause of the proposed decline.

Highlights

Williams & Herd, 1986; Edmonds, 1991; R o c k, In this paper we analyse the view that a major w o o d - 1992).land caribou (Rangifer tarandus caribou) populationT h e management o f any species requires at least decline has recently occurred i n Alberta (Edmonds, 2 levels o f assessment: change i n population size and1986), and we offer a re-assessment o f the limiting the factors causing the change
M a n y provincial often be determined semi-quantitatively within documents refer to this decline as the premise for the broad limits, while the latter are considerably more designation o f Alberta's woodland caribou as an difficult to assess
W e viability of the remaining herds is either threatened or re-assessed aerial surveys for woodland caribou to unknown." Fig. 1 shows the Alberta caribou populati- examine the validity o f provincial population estion trend as outlined i n the 1986 draft Woodland mates and the rate o f decline suggested by F i g . 1

Summary

Introduction

Williams & Herd, 1986; Edmonds, 1991; R o c k , In this paper we analyse the view that a major w o o d - 1992).land caribou (Rangifer tarandus caribou) populationT h e management o f any species requires at least decline has recently occurred i n Alberta (Edmonds, 2 levels o f assessment: change i n population size and1986), and we offer a re-assessment o f the limiting the factors causing the change. 1. Proposed woodland caribou population decline for Alberta from 1900-1986 as originally presented in Edmonds (1986).

Results

Conclusion