Monitoring restoration success: Assessing Marine- Freshwater Food Web Linkages Using Stable Isotopes Dr. Karen Wilson, University of Southern Maine Dr. Graham Sherwood, Gulf of Maine Research Institute Dr. Jonathan Grabowski, Gulf of Maine Research Institute Dr. Theodore Willis, University of Southern Maine – Aquatic Systems Group
Monitoring restoration success: Assessing Marine-Freshwater Food Web Linkages Using Stable Isotopes. Dr. Karen Wilson, University of Southern Maine Dr. Graham Sherwood, Gulf of Maine Research Institute Dr. Jonathan Grabowski, Gulf of Maine Research Institute - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Dr. Karen Wilson, University of Southern MaineDr. Graham Sherwood, Gulf of Maine Research
InstituteDr. Jonathan Grabowski, Gulf of Maine Research
InstituteDr. Theodore Willis, University of Southern Maine –
Aquatic Systems Group
Juven
ile lamp
rey m
igrate to
sea
sea lamprey larvae
Sp
awn
ing
sea lam
prey
April May June July Aug Sept Oct Nove
stu
ary
tid
al
bra
ck
ish
tid
al
fre
sh
Ma
ins
tem
o
r tr
ibu
tary
po
nd
s/l
ak
es
Elvers m
ove u
pstream
Matu
re adu
lt eels leave freshw
ater
Ad
ult alew
ife
Spawning ALE
AL
E Y
OY
exit lakes
AL
E Y
OY
exit lakes
ALE YOY
Sh
ad
Spawning shadS
had
YO
Y exit river
shad YOY
Salmon parr
Ad
ult salm
on
Spawningsalmon
Salm
on
smo
lt exit river
Ad
ult b
lueb
acks
Blu
eback
YO
Y
Sp
awn
ing
b
lueb
acks
Blu
eback Y
OY
exit river
Sm
elt Y
OY
exit river
Sm
elt ad
smelt YOY
Sp
awn
ing
Sm
elt
Also in the lower river:Shortnose sturgeonAtlantic sturgeonTomcodStriped Bass
Penobscot River Restoration Project
Food Web Restoration Indicators
Indicator Rationale & desired outcomes
Trophic levels
More trophic levels = •more diverse predator-prey interactions•greater prey availability•greater ecosystem complexity (i.e., more pathways for food web interactions)
Connectivity Greater reliance on prey from non-focal habitats (i.e., marine vs. freshwater) indicating increased marine-freshwater linkages
See http://www.umaine.edu/searunfish/penobscotexchange/PRFramework_final.pdf
Carbon and Nitrogen stable isotopes: “you are what you eat”• Light (common) & heavy (rare) isotope
forms differ by # of neutrons• Heavy nitrogen (15N) is more difficult to
excrete, so is accumulated from prey to predator as it moves up the food chain
• Approximately 3 – 4 δ15N(‰) units between trophic levels (primary producer, primary consumer, secondary consumer, etc)
• Primary producers [plants] assimilate heavy carbon (13C) under carbon-limited conditions, which vary depending upon habitat
• Animals do not distinguish between heavy & light carbon, so carbon reflects the original source of carbon in their prey
You are what you eat:
• 15N indicates trophic position• 13C indicates habitat- in this
case:– freshwater (lighter) – marine (heavier)
• Other critical advantage: stable isotope signatures of slow turn-over tissues integrate feeding relationships over many months
With increases in anadromous fish, particularly alewife, it is