Stable isotopes reveal rail-associated behavior in a threatened carnivore

† Contribution to the Special Issue “Stable Isotopes in Mammals”.

Figures & data

Figure 1. The transportation corridor in Banff National Park, Alberta, Canada.

Table 1.  Isotope values (δ¹³C, δ¹⁵N, δ³⁴S) for bears killed and captured on the railway in Banff National Park, 2000–2012.

Park ID	Sex	Date killed	Hair-year	δ^13C	δ^15N	δ^34S
Killed bears (n=9)
171	F	8/17/00	1999	−23.7	4.5	10.9
46	F	9/13/04	2004	−22.6	3.8	6.9
4202^b	UNK	5/31/05	2004	−23.5	4.6	9.8
66^a	F	8/19/05	2003	−23.2	6.3	6.0
4346	F	6/18/07	2006	−23.2	4.3	5.6
109	F	5/27/10	2009	−22.7	4.1	6.8
4586	M	6/25/10	2009	−22.5	5.1	7.2
176	F	9/30/11	2001	−23.6	4.7	10.8
UNK	M	11/24/11	2011	−22.6	5.7	8.6
Mean				−23.1	4.8	8.1
SD				0.5	0.8	2.0
Captured bears (n=9)
122	M	4/18/12	2011	−23.0	7.0	9.0
125	M	5/23/12	2011	−23.1	3.3	7.5
126	M	5/26/12	2011	−23.7	5.4	9.2
72	F	6/1/12	2011	−23.7	5.4	10.2
130	F	6/7/12	2011	−23.6	4.7	3.2
132	M	6/14/12	2011	−23.4	5.0	4.6
134	M	6/23/12	2011	−23.1	6.0	6.8
135	F	6/25/12	2011	−23.5	4.7	2.4
136	M	6/27/12	2011	−23.3	6.7	5.7
Mean				−23.4	5.4	6.5
SD				0.3	1.1	2.7
Males (n=8)
Mean		−23.1	5.5	7.3
SD		0.4	1.2	1.6
Females(n=9)
Mean		−23.3	4.7	7.0
SD		0.4	0.7	3.1
Rail-associated bears (n=18)
Mean				−23.2	5.1	7.3
SD				0.4	1.0	2.5

Notes: All isotope values are expressed in delta (δ ) notation as parts per thousand (\permil). Hair-year denotes the year isotopes were assimilated into the hair. Suess corrections account for the global decrease of ¹³C concentration in Earth surface carbon reservoirs, primarily due to fossil fuel burning over the past 150 years [42].

^aHair collected a year prior to being killed.

^bSub-adult bear; age and sex unknown.

Figure 2. Boxplots depicting nitrogen (δ¹⁵N; Panel a), sulfur (δ³⁴S; Panel b), and carbon (δ¹³C; Panel c) isotope values derived from the hair of grizzly bears killed (black squares) or captured (black circles) on the railway (defined as rail-associated bears; Panel d) and those sampled via hair-snare (grey diamonds; Panel d) in Banff National Park, Alberta, Canada, 2000–2012.

Francey RJ, Allison CE, Etheridge DM, Trudinger CM, Enting IG, Leuenberger M, Langenfelds RL, Michel E, Steele LP. A 1000-year high precision record of δ13C in atmospheric CO2. Tellus B. 1999;51:170–193. doi: 10.1034/j.1600-0889.1999.t01-1-00005.x

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