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Effects of a flooding event on a threatened black bear population in L ouisiana
Author(s) -
O'ConnellGoode K. C.,
Lowe C. L.,
Clark J. D.
Publication year - 2014
Publication title -
animal conservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.111
H-Index - 85
eISSN - 1469-1795
pISSN - 1367-9430
DOI - 10.1111/acv.12114
Subject(s) - threatened species , flooding (psychology) , flood myth , population , geography , habitat , ecology , biology , demography , archaeology , psychology , sociology , psychotherapist
Abstract The L ouisiana black bear, U rsus americanus luteolus , is listed as threatened under the E ndangered S pecies A ct 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 U pper A tchafalaya R iver B asin ( 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 M organza S pillway was opened to divert floodwaters from the M ississippi R iver 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 (ψ F → NF ) 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 ψ F → NF 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.