Impacts of exotic species to foodweb structure of Hawaiian streams
-
Upload
amery-hendricks -
Category
Documents
-
view
32 -
download
1
description
Transcript of Impacts of exotic species to foodweb structure of Hawaiian streams
![Page 1: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/1.jpg)
Impacts of exotic species to foodweb structure of Hawaiian streams
Richard A. MacKenzie, Tara Holitzki, Karla McDermid
![Page 2: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/2.jpg)
![Page 3: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/3.jpg)
Research objectivesTo document how poeciliids are affecting Hawaiian streams.
We hypothesized that high densities of omnivorous poeciliids would:H1. shift food resources available for native gobiesH2. shift trophic position of native gobies
![Page 4: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/4.jpg)
Study site
1. Substrate2. Riparian canopy3. Watershed4. Land use5. Elevation6. Stream width
![Page 5: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/5.jpg)
• Collected samples for d13C, d15N, dD
1) Leaf litter2) Algae (epilithon scrapes)3) Invertebrates (surber)4) L. concolor and P. reticulata
(dipnets)
METHODS
![Page 6: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/6.jpg)
13C (‰)
-26 -24 -22 -20 -18 -16 -14
1
5N
(‰
)
2
4
6
8
ChironomidaeC. analisL. concolor
![Page 7: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/7.jpg)
13C (‰)
-26 -24 -22 -20 -18 -16 -14
1
5N
(‰
)
2
4
6
8
ChironomidaeC. analis (Green)C. analis (Brown)
Dugesia sp. Col 25 vs Col 26 L. concolor
Multiple food resources
![Page 8: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/8.jpg)
Chironomid
C. analis (G)
C. analis (B)
Dugesia
Per
cen
t co
ntr
ibu
tio
n
0
20
40
60
80
100Gobies in poeciliid-free streamsGobies in poeciliid-invaded streams
*
A
MacKenzie et al. in review
![Page 9: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/9.jpg)
FCL INV
Chiron
omid
C. ana
lis (G
)
C. ana
lis (B
)
Duges
ia
Per
cen
t co
ntr
ibu
tio
n
0
20
40
60
80
100Exotic poeciliids in poeciliid-invaded streamsNative gobies in poeciliid-invaded streams
B
*
MacKenzie et al. in review
![Page 10: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/10.jpg)
41-44%36-56%
![Page 11: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/11.jpg)
41-44%36-56%
93% 68%32%
![Page 12: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/12.jpg)
???%
![Page 13: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/13.jpg)
Trophic position of L. concolor
Trophic positionconsumer = (d15Nconsumer – d15Nbaseline)/3.4 + 2
Vander Zanden et al. 1999
Poeciliid-free Poeciliid-invaded
Fo
od
Ch
ain
Len
gth
0
1
2
3
4p < 0.05
![Page 14: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/14.jpg)
Conclusions1. Invasion of Hawaiian streams by exotic poeciliids are
altering food web structure of native stream fish by shifting food resources from high (i.e., Chironomidae) to low quality food sources (i.e., Cheumatopsyche analis)
2. Trophic position of L. concolor decreased by 1/2 trophic lengthin poeciliid-invaded streams
3. The introduction of exotic invertebrates to Hawaiian streams (i.e., C. analis) may be altering food web structure by shifting basal food resources (e.g., increased importance of leaf litter)
![Page 15: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/15.jpg)
Impacts of exotic species to foodweb structure of Hawaiian anchialine ponds
Bruce Dudley, Richard A. MacKenzie, Troy Sakihara
![Page 16: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/16.jpg)
kiawe native veg.
open (no fish)
open (fish)
![Page 17: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/17.jpg)
Anchialine pool food web
D (‰)
-220 -200 -180 -160 -140 -120 -100
1
3C
(‰
)
-26
-24
-22
-20
-18
-16
-14
-12
-10
kiawemiloopen (no fish)open (fish)
algae
algae
leaflitter
leaflitter
![Page 18: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/18.jpg)
Chironomidae65%
Diptera15%
JV Atyids12%
Larval Atyids5%
C. analis3%
Lentipes concolor gut content
![Page 19: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/19.jpg)
Hawai‘i
Oahu
![Page 20: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/20.jpg)
D (‰)
-170 -160 -150 -140 -130 -120 -110 -100 -90
15N
(‰
)
3
4
5
6
7
8
9
10 Midge fly (chironomid)
Caddisfly
L. concolor (non-invaded stream)
MacKenzie et al. in review
![Page 21: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/21.jpg)
D (‰)
-170 -160 -150 -140 -130 -120 -110 -100 -90
15N
(‰
)
3
4
5
6
7
8
9
10 Midge fly (chironomid)CaddisflyL. concolor (invaded stream)L. concolor (non-invaded stream)P. reticulata
MacKenzie et al. in review
![Page 22: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/22.jpg)
Trophic positionconsumer = (d15Nconsumer – d15Nbaseline)/3.4 + 2
• Calculated percent contributions to diets using ISOSOURCE (Phillips and Gregg 2003)
• Calculated trophic position (Vander Zanden et al. 1999)
METHODSMETHODS
![Page 23: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/23.jpg)
Invasive taxa in Pearl Harbor
No.
Aquatic insects 49
Crustaceans 5
Mollusks 10
Amphibians 3
Fish 18
Cheumatopsyche analisProcambrus clarkii
Pomacea canaliculata
Englund 2002
Rana catesbeiana
Bufo marinus
Sarotherodon melanochromis
Gambusia affinis
![Page 24: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/24.jpg)
40%
60%
80%20%
Vander Zanden et al. 1999
![Page 25: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/25.jpg)
13C (‰)
-26 -24 -22 -20 -18 -16 -14
1
5N
(‰
)
2
4
6
8
ChironomidaeC. analis
![Page 26: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/26.jpg)
13C (‰)
-26 -24 -22 -20 -18 -16 -14
1
5N
(‰
)
2
4
6
8
ChironomidaeC. analisL. concolor
![Page 27: Impacts of exotic species to foodweb structure of Hawaiian streams](https://reader037.fdocuments.in/reader037/viewer/2022102818/56812b7b550346895d8f99e0/html5/thumbnails/27.jpg)
13C
-26 -24 -22 -20 -18 -16 -14
1
5N
(‰
)
2
4
6
8
ChironomidaeC. analisL. concolor