The response of orthotropic rhizome elongation and primary production of Posidonia oceanica to anthropogenic perturbations and potential confounding effects of shoot age were assessed using a Linear Multilevel Model (LMM). This model examined the confounding effect of age by comparing the estimates of impact and variance components obtained by excluding and including Age as an explanatory variable. Age had a negative effect on rhizome elongation and primary production with an annual decrease of 0.6 mm y−1 and 7 mg dw y−1 respectively. According to the LMM when age effect was omitted, the differences between disturbed and control locations in rhizome elongation and primary production were 2.62 mm y−1 and 0.044 g dw y−1 respectively. These effects were statistically not significant. On the contrary, when age effect was included in the statistical model, impacts became evident for both variables, with significant differences between disturbed and control locations of 5.85 mm y−1 and 0.081 g dw y−1 for rhizome elongation and primary production, respectively. Thus, particular attention should be paid to the potential confounding effect of shoots age in analyses of impacts on growth performance of P. oceanica.

TOMASELLO A, CALVO S, DI MAIDA G, LOVISON G, PIRROTTA M, & SCIANDRA M (2007). Shoot age as a confounding factor on detecting the effect of human-induced disturbance on Posidonia oceanica growth performance. JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY, 343(2), 166-175 [10.1016/j.jembe.2006.11.017].

Shoot age as a confounding factor on detecting the effect of human-induced disturbance on Posidonia oceanica growth performance

TOMASELLO, Agostino;CALVO, Sebastiano;DI MAIDA, Germana;LOVISON, Gianfranco;PIRROTTA, Maria;SCIANDRA, Mariangela
2007

Abstract

The response of orthotropic rhizome elongation and primary production of Posidonia oceanica to anthropogenic perturbations and potential confounding effects of shoot age were assessed using a Linear Multilevel Model (LMM). This model examined the confounding effect of age by comparing the estimates of impact and variance components obtained by excluding and including Age as an explanatory variable. Age had a negative effect on rhizome elongation and primary production with an annual decrease of 0.6 mm y−1 and 7 mg dw y−1 respectively. According to the LMM when age effect was omitted, the differences between disturbed and control locations in rhizome elongation and primary production were 2.62 mm y−1 and 0.044 g dw y−1 respectively. These effects were statistically not significant. On the contrary, when age effect was included in the statistical model, impacts became evident for both variables, with significant differences between disturbed and control locations of 5.85 mm y−1 and 0.081 g dw y−1 for rhizome elongation and primary production, respectively. Thus, particular attention should be paid to the potential confounding effect of shoots age in analyses of impacts on growth performance of P. oceanica.
TOMASELLO A, CALVO S, DI MAIDA G, LOVISON G, PIRROTTA M, & SCIANDRA M (2007). Shoot age as a confounding factor on detecting the effect of human-induced disturbance on Posidonia oceanica growth performance. JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY, 343(2), 166-175 [10.1016/j.jembe.2006.11.017].
File in questo prodotto:
File Dimensione Formato  
Tomasello.pdf

non disponibili

Dimensione 524.12 kB
Formato Adobe PDF
524.12 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/14842
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 20
  • ???jsp.display-item.citation.isi??? 19
social impact