The effect of initial biomass in manipulative experiments on plants

2047 5 9172 2 24690 document 9172 Kikvidze et al 2006 Funct Ecol.pdf application/pdf c340277f2eabca24636755b5f43221ea MD5 91906 2014-01-23 07:54:34 http://eprints.iliauni.edu.ge/2047/1/Kikvidze%20et%20al%202006%20Funct%20Ecol.pdf 2047 1 1 application/pdf text en public

Kikvidze et al 2006 Funct Ecol.pdf

9174 3 24692 document 9174 lightbox.jpg image/png 81e47ef13cabf41e4b7b6a528659711c MD5 54517 2014-01-23 08:04:40 http://eprints.iliauni.edu.ge/2047/3/lightbox.jpg 2047 3 3 image/png other Thumbnails conversion from text to thumbnail_lightbox ge public

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http://eprints.org/relation/isVersionOf http://eprints.iliauni.edu.ge/id/document/9172 http://eprints.org/relation/isVolatileVersionOf http://eprints.iliauni.edu.ge/id/document/9172 http://eprints.org/relation/issmallThumbnailVersionOf http://eprints.iliauni.edu.ge/id/document/9172 archive 137 disk0/00/00/20/47 2015-04-16 06:21:00 2015-04-16 06:21:00 2015-04-16 06:21:00 article 461 show Kikvidze Zaal zaal.kikvidze@iliauni.edu.ge Armas Cristina cris@eeza.csic.es Pugnaire Francisco fip@eeza.csic.es The effect of initial biomass in manipulative experiments on plants pub QEC ins18 public Mass is often used as a measure of plant performance in manipulative experiments (Eviner et al. 2000; Shen & Harte 2000). Experimental manipulations may be very diverse: from addition of nutrients, to changing abiotic growth conditions, to removing or adding biotic components such as neighbours, herbivores, etc. But, in general, researchers try to clarify the effect of one factor by comparing the biomass of naturally growing plants (or transplants, or planted phytometers) under control and manipulated conditions. Experiments usually start with individuals that are young enough to avoid previous environmental effects, but mature enough to ensure survival and correct identification if several species are used. As a consequence, target individuals in both treatment and control have an initial mass prior to experiments. Established individuals are grown in different conditions and then harvested. The performance of target individuals is assessed by their final dry mass, and the initial value is often ignored in these analyses (Goldberg et al. 1999). However, ignoring the initial mass may conceal the treatment effects. Here we explore this problem, and show how ignoring initial biomass can cause systematic bias, particularly when experimental manipulation reduces plant performance compared with the control. 2006 Functional Ecology 20 British Ecological Society 1-3 TRUE 1365-2435