Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes
Seabirds outside the NE Pacific and NE Atlantic regions are poorly understood from a trophic perspective. To elucidate trophic level relationships, we examined the concentration of ∂13C and ∂15N in the blood, breast muscle, and feathers of nine species of adult marine-associated birds common in Sout...
Main Authors: | , , , |
---|---|
Format: | Still Image |
Language: | unknown |
Published: |
NSUWorks
2016
|
Subjects: | |
Online Access: | https://nsuworks.nova.edu/occ_facpresentations/664 |
id |
ftnsoutheastern:oai:nsuworks.nova.edu:occ_facpresentations-1649 |
---|---|
record_format |
openpolar |
spelling |
ftnsoutheastern:oai:nsuworks.nova.edu:occ_facpresentations-1649 2023-05-15T18:50:55+02:00 Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes Kerstetter, David Young, Michael Hirons, Amy Martinez, Zara 2016-09-22T07:00:00Z https://nsuworks.nova.edu/occ_facpresentations/664 unknown NSUWorks https://nsuworks.nova.edu/occ_facpresentations/664 Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures Marine Biology Oceanography and Atmospheric Sciences and Meteorology poster 2016 ftnsoutheastern 2022-04-10T22:08:40Z Seabirds outside the NE Pacific and NE Atlantic regions are poorly understood from a trophic perspective. To elucidate trophic level relationships, we examined the concentration of ∂13C and ∂15N in the blood, breast muscle, and feathers of nine species of adult marine-associated birds common in South Florida: osprey Pandion haliaetus, black skimmer Rynchops niger, brown pelican Pelecanus occidentalis, northern gannet Morus bassanus, double-crested cormorant Phalacrocorax auritus, royal tern Thalasseus maximus, herring gull Larus argentatus, laughing gull Leucophaeus atricilla, and ring-billed gull Larus delawarensis. We collected specimens from four wildlife rehabilitation centers after death; three centers were in mainland-coastal areas, while one was coastal-island. Calculated mean trophic levels (TLs) ranged from 5.15 (osprey and northern gannet) to 3.64 (ring-billed gull), findings consistent with existing diet information, and all species exhibited expected ∂13C:∂15N ratios. Herring and laughing gulls (TL 4.59 and 3.90, respectively) appear to have a straight trophic enrichment based on coastal POM. Northern gannets (TL 5.15) are likely consuming a limited diet in offshore areas consistent with POM-based enrichment patterns and feeding strategies. Brown pelicans, osprey, and royal terns (TLs 4.78, 5.15, and 4.11, respectively) overlap diets when in South Florida, likely reflecting feeding areas; consistent with field observations, when onshore winds are strong, these species feed inshore on carbon-enriched prey, but when winds are weak, they feed near/offshore on carbon-depleted prey, such as lipid-rich fishes. However, double-crested cormorants (TLs 3.40 to 5.59) appear to have an unusually bifurcated ∂13C and ∂15N signal between specimens, apparently representing the two habitats inhabited by individual birds in South Florida: one along the coastal/nearshore ecotone and one along the inland/coastal ecotone. Still Image osprey Pandion haliaetus Nova Southeastern University: NSU Works Pacific |
institution |
Open Polar |
collection |
Nova Southeastern University: NSU Works |
op_collection_id |
ftnsoutheastern |
language |
unknown |
topic |
Marine Biology Oceanography and Atmospheric Sciences and Meteorology |
spellingShingle |
Marine Biology Oceanography and Atmospheric Sciences and Meteorology Kerstetter, David Young, Michael Hirons, Amy Martinez, Zara Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
topic_facet |
Marine Biology Oceanography and Atmospheric Sciences and Meteorology |
description |
Seabirds outside the NE Pacific and NE Atlantic regions are poorly understood from a trophic perspective. To elucidate trophic level relationships, we examined the concentration of ∂13C and ∂15N in the blood, breast muscle, and feathers of nine species of adult marine-associated birds common in South Florida: osprey Pandion haliaetus, black skimmer Rynchops niger, brown pelican Pelecanus occidentalis, northern gannet Morus bassanus, double-crested cormorant Phalacrocorax auritus, royal tern Thalasseus maximus, herring gull Larus argentatus, laughing gull Leucophaeus atricilla, and ring-billed gull Larus delawarensis. We collected specimens from four wildlife rehabilitation centers after death; three centers were in mainland-coastal areas, while one was coastal-island. Calculated mean trophic levels (TLs) ranged from 5.15 (osprey and northern gannet) to 3.64 (ring-billed gull), findings consistent with existing diet information, and all species exhibited expected ∂13C:∂15N ratios. Herring and laughing gulls (TL 4.59 and 3.90, respectively) appear to have a straight trophic enrichment based on coastal POM. Northern gannets (TL 5.15) are likely consuming a limited diet in offshore areas consistent with POM-based enrichment patterns and feeding strategies. Brown pelicans, osprey, and royal terns (TLs 4.78, 5.15, and 4.11, respectively) overlap diets when in South Florida, likely reflecting feeding areas; consistent with field observations, when onshore winds are strong, these species feed inshore on carbon-enriched prey, but when winds are weak, they feed near/offshore on carbon-depleted prey, such as lipid-rich fishes. However, double-crested cormorants (TLs 3.40 to 5.59) appear to have an unusually bifurcated ∂13C and ∂15N signal between specimens, apparently representing the two habitats inhabited by individual birds in South Florida: one along the coastal/nearshore ecotone and one along the inland/coastal ecotone. |
format |
Still Image |
author |
Kerstetter, David Young, Michael Hirons, Amy Martinez, Zara |
author_facet |
Kerstetter, David Young, Michael Hirons, Amy Martinez, Zara |
author_sort |
Kerstetter, David |
title |
Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
title_short |
Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
title_full |
Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
title_fullStr |
Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
title_full_unstemmed |
Assessment of Trophic Positions for the Seabirds of South Florida using C and N Stable Isotopes |
title_sort |
assessment of trophic positions for the seabirds of south florida using c and n stable isotopes |
publisher |
NSUWorks |
publishDate |
2016 |
url |
https://nsuworks.nova.edu/occ_facpresentations/664 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
osprey Pandion haliaetus |
genre_facet |
osprey Pandion haliaetus |
op_source |
Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures |
op_relation |
https://nsuworks.nova.edu/occ_facpresentations/664 |
_version_ |
1766244693033615360 |