effects of resource availability on juvenile dispersal and settlement
Post on 21-Dec-2015
219 views
TRANSCRIPT
![Page 1: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/1.jpg)
Effects of resource availability on juvenile dispersal and settlement
![Page 2: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/2.jpg)
Dispersal & Resources
• central determinant of a species’ ecology
• energetically expensive
• dispersal behaviour related to physical condition or access to energy reserves
![Page 3: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/3.jpg)
Energetic mediation of dispersal
Belding’s ground squirrel(Spermophilus beldingi)Nunes et al. 1999
Greater flamingo(Phoenicopterus ruber roseus)Barbraud et al. 2003
Common lizard(Lacerta vivipara)Massot and Clobert 1995
Spanish imperial eagle(Aquila adalberti)Ferrer et al. 1992
photo by Don Baccus
photo by Howard Inns
photo from Smithsonian Institute
photo from Just Birds
![Page 4: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/4.jpg)
Resource paradox
• Do increased local resources encourage or provide an advantage for dispersal or philopatry?
Photo by Sébastien Descamps
![Page 5: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/5.jpg)
Dispersal trade-off
Costs• energetically expensive• predation risk• territory quality
Benefits• avoid kin competition• avoid inbreeding• territory quality
![Page 6: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/6.jpg)
Objectives and Expectations
Determine energetic influences on:
• growth rate
• exploratory forays
• degree of dispersal or philopatry
• territory takeover attempts
• size and quality of territory settled
• successful settlement and survival
![Page 7: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/7.jpg)
• maternal food supplementationautumn 2003 to Spring 2004
• autumn 2003 n=31 females
• winter 2004food add n=15
control n=13
Team Lloyd
![Page 8: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/8.jpg)
0
2
4
6
8
10
12
14
16
breeders non-breeders breeders non-breeders
food-add control
Number of breeding females
![Page 9: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/9.jpg)
Number of females surviving
0
2
4
6
8
10
12
14
16
breeders non-breeders
food-add control
disappear/predation
survive
control
![Page 10: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/10.jpg)
food-add control20-Mar
03-Apr
17-Apr
01-May
15-May
29-May
12-Jun
food-add control
Parturition dates
![Page 11: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/11.jpg)
Litter sizes
food-add
control
0
1
2
3
4
5
6
1 2 3 4 5
litter size
freq
uen
cy
0
1
2
3
4
5
6
1 2 3 4 5
litter size
freq
uen
cy
![Page 12: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/12.jpg)
0
5
10
15
20
25
emerged failed emerged failed
food-add (n=9) control (n=5)
0
0.2
0.4
0.6
0.8
1
0 1 2 3
Juvenile emergence
Number of emerged vs failed juveniles
Average proportion of litter emerged
food-add control
![Page 13: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/13.jpg)
Team Lloyd
Circuit trapping– all middens within 90 m radius of natal area– until 100 days old– 150-175 hours of trapping per litter– weight taken at each capture
![Page 14: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/14.jpg)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0 50 100 150 200
age (days)
mas
s (g
)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0 50 100 150 200
age (days)m
as
s (
g)
Individual growth rates
food-add control
![Page 15: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/15.jpg)
Average growth rates
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0 50 100 150 200
age (days)
mas
s (g
)
food-add
control
![Page 16: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/16.jpg)
Settlement criteria
1. rattled on midden on more than one day
2. trapped at least 3 times at same midden
3. assumption for one rattle during August census – late litters
4. day 100?
![Page 17: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/17.jpg)
Settlement criteria
1. rattled on midden on more than one day
2. trapped at least 3 times at same midden
3. assumption for one rattle during August census – late litters
4. day 100?
![Page 18: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/18.jpg)
Settlement criteria
1. rattled on midden on more than one day
2. trapped at least 3 times at same midden
3. assumption for one rattle during August census – late litters
4. day 100?
![Page 19: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/19.jpg)
Settlement criteria
1. rattled on midden on more than one day
2. trapped at least 3 times at same midden
3. assumption for one rattle during August census – late litters
4. day 100?
![Page 20: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/20.jpg)
Settlement criteria
1. rattled on midden on more than one day
2. trapped at least 3 times at same midden
3. assumption for one rattle during August census – late litters
4. day 100?
![Page 21: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/21.jpg)
Settlement of emerged juveniles
90% settlement in both food-add and control at individual level
food-add litters n= 12 control litters n=5
0
5
10
15
20
25
30
food-add control
did not settle
settled
![Page 22: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/22.jpg)
0
20
40
60
80
100
120
140
0 1 2 3
Ag
e (
da
ys
)Age at settlement
food-add control
![Page 23: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/23.jpg)
Maximum foray distance
food-add n = 28 from 12 litters (154.84 ± 179.60)
control n= 10 from 5 litters (95.41 ± 37.96)
0
1
2
3
0 100 200 300 400 500 600 700 800
distance (m)
food-add
control
![Page 24: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/24.jpg)
Maximum settlement distance
food-add n = 24 from 12 litters (116.19 ± 172.84)
control n= 9 from 5 litters (76.47 ± 56.56)
0
1
2
3
0 100 200 300 400 500 600 700 800
distance (m)
food-add
control
![Page 25: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/25.jpg)
Team Lloyd
Territory mapping– juveniles radio-collared– radio-tracked territory boundary– ≥ 30 data points
![Page 26: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/26.jpg)
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
-10.0 -5.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0
square = food add circle = controlgrid line = 150 m
Juvenile territory mapping
![Page 27: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/27.jpg)
Team Lloyd
Territory quality indexMidden condition
• ranked midden quality and activity
Cone production• assessed with cone
counts
Tree density
Spruce bark beetle kill
![Page 28: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/28.jpg)
Survival of settled juveniles
0
5
10
15
20
25
30
food-add control
disappear
survive
![Page 29: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/29.jpg)
Proportion of total juveniles settled
0.0
20.0
40.0
60.0
80.0
100.0
food-add control
%
failure
success
![Page 30: Effects of resource availability on juvenile dispersal and settlement](https://reader030.vdocuments.net/reader030/viewer/2022032704/56649d605503460f94a41567/html5/thumbnails/30.jpg)
Too cute not to include