Shima and Osenberg 2003 - Ecology reprint.pdf (414.2 kB)

Cryptic density dependence: effects of spatio-temporal covariation between density and site quality in reef fish

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journal contribution
posted on 28.09.2020 by Jeffrey Shima, C Osenberg
The importance and strength of density dependence continues to engender debate because of its central importance to population dynamics and regulation. Here, we show how confounding effects of site quality can mask strong effects of density dependence. In particular, we explore spatiotemporal variation and covariation among (1) densities of newly settled coral reef fish (Thalassoma hardwicke), (2) environmental characteristics, and (3) the strength of density-dependent mortality. Environmental features of patch reefs were spatially and temporally variable and influenced density-dependent survival. Higher-quality sites (i.e., reefs possessing features that yield greater numbers of recruits at any given settlement level) received greater settlement, and this relationship masked the operation of density dependence when variation in quality among sites (or times) was not distinguished (a common approach in many Observational studies of density dependence). Our work illustrates how spatiotemporal covariation in settlement density and site quality can obscure patterns of density dependence at larger scales, contributing to a phenomenon we call "cryptic density dependence." Acknowledging patterns and consequences of covariance may alter the way we study population dynamics, especially of marine organisms, where the link between processes that affect settlement and post-settlement survival remains relatively poorly understood.

History

Preferred citation

Shima, J. & Osenberg, C. (2003). Cryptic density dependence: effects of spatio-temporal covariation between density and site quality in reef fish. Ecology, 84(1), 46-52. https://doi.org/10.1890/0012-9658(2003)084[0046:CDDEOC]2.0.CO;2

Journal title

Ecology

Volume

84

Issue

1

Publication date

01/01/2003

Pagination

46-52

Publisher

Wiley

Publication status

Published

Contribution type

Article

ISSN

0012-9658

eISSN

1939-9170

Language

en

Exports