Time constraints in temperate-breeding species: influence of growing season length on reproductive strategies

Ecography
Ducks Unlimited Canada; Environment Canada; Natural Sciences and Engineering Research Council (NSERC); Univ. of Saskatchewan; MBNA Canada Bank; California Waterfowl Association
By: , and 

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Abstract

Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Time constraints in temperate-breeding species: influence of growing season length on reproductive strategies
Series title Ecography
DOI 10.1111/j.1600-0587.2010.06622.x
Volume 34
Issue 4
Year Published 2011
Language English
Publisher Nordic Ecological Society Oikos
Publisher location Copenhagen
Contributing office(s) Coop Res Unit Atlanta
Description 9 p.
First page 628
Last page 636
Online Only (Y/N) N
Additional Online Files (Y/N) N