State-dependent fertility in pinnipeds: contrasting capital and income breeders.
1. The study tested the hypothesis that the occurrence of pregnancy in mammals that are capital breeders will be most closely related to state variables that are indices of food stores. Income breeders would not be expected to have the same relationship. 2. The study examined the relationships betwe...
Main Author: | |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2000
|
Subjects: | |
Online Access: | https://risweb.st-andrews.ac.uk/portal/en/researchoutput/statedependent-fertility-in-pinnipeds-contrasting-capital-and-income-breeders(a06ba0e8-a5cc-4f36-a93b-23f81f5bb481).html http://www.scopus.com/inward/record.url?scp=0033738391&partnerID=8YFLogxK |
id |
ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/a06ba0e8-a5cc-4f36-a93b-23f81f5bb481 |
---|---|
record_format |
openpolar |
spelling |
ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/a06ba0e8-a5cc-4f36-a93b-23f81f5bb481 2023-05-15T13:45:52+02:00 State-dependent fertility in pinnipeds: contrasting capital and income breeders. Boyd, Ian Lamont 2000-10 https://risweb.st-andrews.ac.uk/portal/en/researchoutput/statedependent-fertility-in-pinnipeds-contrasting-capital-and-income-breeders(a06ba0e8-a5cc-4f36-a93b-23f81f5bb481).html http://www.scopus.com/inward/record.url?scp=0033738391&partnerID=8YFLogxK eng eng info:eu-repo/semantics/restrictedAccess Boyd , I L 2000 , ' State-dependent fertility in pinnipeds: contrasting capital and income breeders. ' , Functional Ecology , vol. 14 , pp. 623-630 . fecundity life history mammals seals ANTARCTIC FUR SEALS SOUTHERN ELEPHANT SEALS BODY CONDITION LIFE-HISTORY GREY SEALS BREEDING EXPERIENCE HALICHOERUS-GRYPUS AGE SIZE REPRODUCTION article 2000 ftunstandrewcris 2021-12-26T14:10:39Z 1. The study tested the hypothesis that the occurrence of pregnancy in mammals that are capital breeders will be most closely related to state variables that are indices of food stores. Income breeders would not be expected to have the same relationship. 2. The study examined the relationships between mass, time of year, age and body length with the occurrence of pregnancy in three species of pinniped. This included two capital breeders (Crabeater Seal, Lobodon carcinophagus Hombron & Jacquinot, and Grey Seal, Halichoerus grypus Fabricius) and one income breeder (Antarctic Fur Seal, Arctocephalus gazella Peters). Multiple logistic regression analysis was used to examine the relationships and the interactions between the different state variables. 3. In both the capital breeders the state variables used in the study explained approximately twice the amount of variability (55% compared with 25%) in the occurrence of pregnancy than in the income breeder. Mass was the dominant state variable among both the capital breeders whereas in the income breeder mass was less important both relative to other state variables and in absolute terms. The results support the conclusion that the occurrence of pregnancy in capital breeders is more sensitive to body reserves than it is in income breeders. 4. The results also support the conclusion that life histories are the end result of a variety of functional responses to different state variables that have differing degrees of influence. In particular a size-structured approach to studies of population dynamics in pinnipeds may be a more informative way of predicting population responses to environmental variability than the more traditional age-structured approach. Article in Journal/Newspaper Antarc* Antarctic Antarctic Fur Seal Antarctic Fur Seals Arctocephalus gazella Crabeater Seal Elephant Seals Lobodon carcinophagus Southern Elephant Seals University of St Andrews: Research Portal Antarctic Hombron ENVELOPE(-58.650,-58.650,-63.450,-63.450) Jacquinot ENVELOPE(-57.867,-57.867,-63.350,-63.350) |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
fecundity life history mammals seals ANTARCTIC FUR SEALS SOUTHERN ELEPHANT SEALS BODY CONDITION LIFE-HISTORY GREY SEALS BREEDING EXPERIENCE HALICHOERUS-GRYPUS AGE SIZE REPRODUCTION |
spellingShingle |
fecundity life history mammals seals ANTARCTIC FUR SEALS SOUTHERN ELEPHANT SEALS BODY CONDITION LIFE-HISTORY GREY SEALS BREEDING EXPERIENCE HALICHOERUS-GRYPUS AGE SIZE REPRODUCTION Boyd, Ian Lamont State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
topic_facet |
fecundity life history mammals seals ANTARCTIC FUR SEALS SOUTHERN ELEPHANT SEALS BODY CONDITION LIFE-HISTORY GREY SEALS BREEDING EXPERIENCE HALICHOERUS-GRYPUS AGE SIZE REPRODUCTION |
description |
1. The study tested the hypothesis that the occurrence of pregnancy in mammals that are capital breeders will be most closely related to state variables that are indices of food stores. Income breeders would not be expected to have the same relationship. 2. The study examined the relationships between mass, time of year, age and body length with the occurrence of pregnancy in three species of pinniped. This included two capital breeders (Crabeater Seal, Lobodon carcinophagus Hombron & Jacquinot, and Grey Seal, Halichoerus grypus Fabricius) and one income breeder (Antarctic Fur Seal, Arctocephalus gazella Peters). Multiple logistic regression analysis was used to examine the relationships and the interactions between the different state variables. 3. In both the capital breeders the state variables used in the study explained approximately twice the amount of variability (55% compared with 25%) in the occurrence of pregnancy than in the income breeder. Mass was the dominant state variable among both the capital breeders whereas in the income breeder mass was less important both relative to other state variables and in absolute terms. The results support the conclusion that the occurrence of pregnancy in capital breeders is more sensitive to body reserves than it is in income breeders. 4. The results also support the conclusion that life histories are the end result of a variety of functional responses to different state variables that have differing degrees of influence. In particular a size-structured approach to studies of population dynamics in pinnipeds may be a more informative way of predicting population responses to environmental variability than the more traditional age-structured approach. |
format |
Article in Journal/Newspaper |
author |
Boyd, Ian Lamont |
author_facet |
Boyd, Ian Lamont |
author_sort |
Boyd, Ian Lamont |
title |
State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
title_short |
State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
title_full |
State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
title_fullStr |
State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
title_full_unstemmed |
State-dependent fertility in pinnipeds: contrasting capital and income breeders. |
title_sort |
state-dependent fertility in pinnipeds: contrasting capital and income breeders. |
publishDate |
2000 |
url |
https://risweb.st-andrews.ac.uk/portal/en/researchoutput/statedependent-fertility-in-pinnipeds-contrasting-capital-and-income-breeders(a06ba0e8-a5cc-4f36-a93b-23f81f5bb481).html http://www.scopus.com/inward/record.url?scp=0033738391&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-58.650,-58.650,-63.450,-63.450) ENVELOPE(-57.867,-57.867,-63.350,-63.350) |
geographic |
Antarctic Hombron Jacquinot |
geographic_facet |
Antarctic Hombron Jacquinot |
genre |
Antarc* Antarctic Antarctic Fur Seal Antarctic Fur Seals Arctocephalus gazella Crabeater Seal Elephant Seals Lobodon carcinophagus Southern Elephant Seals |
genre_facet |
Antarc* Antarctic Antarctic Fur Seal Antarctic Fur Seals Arctocephalus gazella Crabeater Seal Elephant Seals Lobodon carcinophagus Southern Elephant Seals |
op_source |
Boyd , I L 2000 , ' State-dependent fertility in pinnipeds: contrasting capital and income breeders. ' , Functional Ecology , vol. 14 , pp. 623-630 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1766231749094801408 |