Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies
Our aim was to develop a method for estimating the number of animals using a single site in an asynchronous species, meaning that not all animals are present at once so that no one count captures the entire population. This is a common problem in seasonal breeders, and in northern elephant seals, we...
Published in: | PLOS ONE |
---|---|
Main Authors: | , , , , , , , |
Other Authors: | , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Public Library of Science (PLoS)
2022
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1371/journal.pone.0262214 https://dx.plos.org/10.1371/journal.pone.0262214 |
id |
crplos:10.1371/journal.pone.0262214 |
---|---|
record_format |
openpolar |
spelling |
crplos:10.1371/journal.pone.0262214 2024-10-13T14:06:56+00:00 Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies Condit, Richard Allen, Sarah G. Costa, Daniel P. Codde, Sarah Goley, P. Dawn Le Boeuf, Burney J. Lowry, Mark S. Morris, Patricia Hoskins, Andrew J. National Science Foundation Office of Naval Research National Park Service Point Blue Conservation Science Bureau of Land Management National Marine Fisheries Service National Geographic Society San Francisco Bay Area Network Inventory and Monitoring Program Point Reyes National Seashore University of California, Santa Cruz 2022 http://dx.doi.org/10.1371/journal.pone.0262214 https://dx.plos.org/10.1371/journal.pone.0262214 en eng Public Library of Science (PLoS) https://creativecommons.org/publicdomain/zero/1.0/ PLOS ONE volume 17, issue 1, page e0262214 ISSN 1932-6203 journal-article 2022 crplos https://doi.org/10.1371/journal.pone.0262214 2024-09-24T04:08:53Z Our aim was to develop a method for estimating the number of animals using a single site in an asynchronous species, meaning that not all animals are present at once so that no one count captures the entire population. This is a common problem in seasonal breeders, and in northern elephant seals, we have a model for quantifying asynchrony at the Año Nuevo colony. Here we test the model at several additional colonies having many years of observations and demonstrate how it can account for animals not present on any one day. This leads to correction factors that yield total population from any single count throughout a season. At seven colonies in California for which we had many years of counts of northern elephant seals, we found that female arrival date varied < 2 days between years within sites and by < 5 days between sites. As a result, the correction factor for any one day was consistent, and at each colony, multiplying a female count between 26 and 30 Jan by 1.15 yielded an estimate of total population size that minimized error. This provides a method for estimating the female population size at colonies not yet studied. Our method can produce population estimates with minimal expenditure of time and resources and will be applicable to many seasonal species with asynchronous breeding phenology, particularly colonial birds and other pinnipeds. In elephant seals, it will facilitate monitoring the population over its entire range. Article in Journal/Newspaper Elephant Seal Elephant Seals PLOS PLOS ONE 17 1 e0262214 |
institution |
Open Polar |
collection |
PLOS |
op_collection_id |
crplos |
language |
English |
description |
Our aim was to develop a method for estimating the number of animals using a single site in an asynchronous species, meaning that not all animals are present at once so that no one count captures the entire population. This is a common problem in seasonal breeders, and in northern elephant seals, we have a model for quantifying asynchrony at the Año Nuevo colony. Here we test the model at several additional colonies having many years of observations and demonstrate how it can account for animals not present on any one day. This leads to correction factors that yield total population from any single count throughout a season. At seven colonies in California for which we had many years of counts of northern elephant seals, we found that female arrival date varied < 2 days between years within sites and by < 5 days between sites. As a result, the correction factor for any one day was consistent, and at each colony, multiplying a female count between 26 and 30 Jan by 1.15 yielded an estimate of total population size that minimized error. This provides a method for estimating the female population size at colonies not yet studied. Our method can produce population estimates with minimal expenditure of time and resources and will be applicable to many seasonal species with asynchronous breeding phenology, particularly colonial birds and other pinnipeds. In elephant seals, it will facilitate monitoring the population over its entire range. |
author2 |
Hoskins, Andrew J. National Science Foundation Office of Naval Research National Park Service Point Blue Conservation Science Bureau of Land Management National Marine Fisheries Service National Geographic Society San Francisco Bay Area Network Inventory and Monitoring Program Point Reyes National Seashore University of California, Santa Cruz |
format |
Article in Journal/Newspaper |
author |
Condit, Richard Allen, Sarah G. Costa, Daniel P. Codde, Sarah Goley, P. Dawn Le Boeuf, Burney J. Lowry, Mark S. Morris, Patricia |
spellingShingle |
Condit, Richard Allen, Sarah G. Costa, Daniel P. Codde, Sarah Goley, P. Dawn Le Boeuf, Burney J. Lowry, Mark S. Morris, Patricia Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
author_facet |
Condit, Richard Allen, Sarah G. Costa, Daniel P. Codde, Sarah Goley, P. Dawn Le Boeuf, Burney J. Lowry, Mark S. Morris, Patricia |
author_sort |
Condit, Richard |
title |
Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
title_short |
Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
title_full |
Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
title_fullStr |
Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
title_full_unstemmed |
Estimating population size when individuals are asynchronous: A model illustrated with northern elephant seal breeding colonies |
title_sort |
estimating population size when individuals are asynchronous: a model illustrated with northern elephant seal breeding colonies |
publisher |
Public Library of Science (PLoS) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1371/journal.pone.0262214 https://dx.plos.org/10.1371/journal.pone.0262214 |
genre |
Elephant Seal Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals |
op_source |
PLOS ONE volume 17, issue 1, page e0262214 ISSN 1932-6203 |
op_rights |
https://creativecommons.org/publicdomain/zero/1.0/ |
op_doi |
https://doi.org/10.1371/journal.pone.0262214 |
container_title |
PLOS ONE |
container_volume |
17 |
container_issue |
1 |
container_start_page |
e0262214 |
_version_ |
1812813172258635776 |