10.5061/DRYAD.41NS1RNDC
Shiratsuru, Shotaro
0000-0001-8747-9664
University of Alberta
Majchrzak, Yasmine
University of Alberta
Peers, Michael
University of Alberta
Studd, Emily
University of Alberta
Menzies, Allyson
McGill University
Derbyshire, Rachael
Trent University
Humphries, Murray
McGill University
Krebs, Charles
University of British Columbia
Murray, Dennis
Trent University
Boutin, Stan
University of Alberta
Food availability and long-term predation risk interactively affect
antipredator response
Dryad
dataset
2021
FOS: Biological sciences
2021-05-27T00:00:00Z
2021-05-27T00:00:00Z
en
137787 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Food availability and temporal variation in predation risk are both
important determinants of the magnitude of antipredator responses, but
their effects have rarely been examined simultaneously, particularly in
wild prey. Here, we determine how food availability and long-term
predation risk affect antipredator responses to acute predation risk by
monitoring the foraging response of free-ranging snowshoe hares (Lepus
americanus) to an encounter with a Canada lynx Lynx canadensis) in Yukon,
Canada, over 4 winters (from 2015-2016 to 2018-2019). We examined how this
response was influenced by natural variation in long-term predation risk
(two-month mortality rate of hares) while providing some individuals with
supplemental food. On average, snowshoe hares reduced foraging time up to
10 hours after coming into close proximity (≤ 75 m) with lynx, and reduced
foraging time an average of 15.28 ± 7.08 minutes per lynx encounter. Hares
tended to respond more strongly when the distance to lynx was shorter.
More importantly, the magnitude of hares’ antipredator response to a lynx
encounter was affected by the interaction between food-supplementation and
long-term predation risk. Food-supplemented hares reduced foraging time
more than control hares after a lynx encounter under low long-term risk,
but decreased the magnitude of the response as long-term risk increased.
In contrast, control hares increased the magnitude of their response as
long-term risk increased. Our findings show that food availability and
long-term predation risk interactively drive the magnitude of reactive
antipredator response to acute predation risk. Determining the factors
driving the magnitude of antipredator responses would contribute to a
better understanding of the indirect effects of predators on prey
populations.
Snowshoe hare-lynx encounter events were identified by simultaneous GPS
fixes, and foraging time of snowshoe hares before and after lynx encounter
was calculated from accelerometer data. To estimate two-month mortality
rate of control hares, we first estimated two-month (November-December,
January-February, March-April) survival rate of hares for each winter
using the Kaplan-Meier method accounting for left-truncation with survival
package in R (Therneau 2015), and then calculated mortality rate by
subtracting survival rate from 1. Hares that survived were censored on the
last day for each monitoring period (2 months), and lost hares were
censored on the day they went missing.