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Effects of a flooding event on a threatened black bear population in Louisiana

Animal Conservation

By:
, , and
DOI: 10.1111/acv.12114

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Abstract

The Louisiana black bear, Ursus americanus luteolus, is listed as threatened under the Endangered Species Act as a result of habitat loss and human-related mortality. Information on population-level responses of large mammals to flooding events is scarce, and we had a unique opportunity to evaluate the viability of the Upper Atchafalaya River Basin (UARB) black bear population before and after a significant flooding event. We began collecting black bear hair samples in 2007 for a DNA mark-recapture study to estimate abundance (N) and apparent survival (φ). In 2011, the Morganza Spillway was opened to divert floodwaters from the Mississippi River through the UARB, inundating > 50% of our study area, potentially impacting recovery of this important bear population. To evaluate the effects of this flooding event on bear population dynamics, we used a robust design multistate model to estimate changes in transition rates from the flooded area to non-flooded area (ψFNF) before (2007–2010), during (2010–2011) and after (2011–2012) the flood. Average N across all years of study was 63.2 (SE = 5.2), excluding the year of the flooding event. Estimates of ψFNF increased from 0.014 (SE = 0.010; meaning that 1.4% of the bears moved from the flooded area to non-flooded areas) before flooding to 0.113 (SE = 0.045) during the flood year, and then decreased to 0.028 (SE= 0.035) after the flood. Although we demonstrated a flood effect on transition rates as hypothesized, the effect was small (88.7% of the bears remained in the flooded area during flooding) and φ was unchanged, suggesting that the 2011 flooding event had minimal impact on survival and site fidelity.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Effects of a flooding event on a threatened black bear population in Louisiana
Series title:
Animal Conservation
DOI:
10.1111/acv.12114
Volume
17
Issue:
5
Year Published:
2014
Language:
English
Publisher:
Wiley
Contributing office(s):
Leetown Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Animal Conservation
First page:
476
Last page:
485
Country:
United States
State:
Louisiana
Other Geospatial:
Upper Atchafalaya River Basin