Calibración de un modelo alométrico para evaluar la producción foliar de Zostera marina L.

In this paper a mathematical model to predict the foliage production of Z. marina es proposed. This model presents the foliage production expressed in dry weight, as function of length and width of the leaves. The calibration of the model was made with samples taken in two different levels of exposure in Bahía Falsa, San Quintín, Baja California, México. The high values of the determination coefficient and the small values of the standard errors of the fitting data as well as the parameters found by the regression, and the small values of the absolute and standard errors between the observed and calculated values, indicate that the model is adequate.En este trabajo se propone un modelo matemático para predecir la producción foliar de Z. marina, expresada como peso seco en función del largo y ancho de las hojas. La calibración del modelo se realizó con muestras colectadas a dos diferentes niveles de exposición, en Bahía Falsa, San Quintín, Baja California, México. Los elevados de los coeficientes de determinación, los bajos valores de los errores estándar, tanto de los ajustados como de los parámetros obtenidos y los bajos valores de los errores estándar y absoluto, entre los valores encontados y los calculados, indican que el modelo es adecuado

Sheath length as a monitoring tool for calculating leaf growth in eelgrass (Zostera marina L.)

Recent advances have improved ease and accuracy in seagrass growth measurements. Despite these improvements, seagrass leaf growth can be difficult to measure effectively; current methods are destructive to the plants and require at least two site visits per growth period. We used the “previous growth” of Ibarra-Obando and Boudouresque [Ibarra-Obando, S.E., Boudouresque, C.F., 1994. An improvement of the Zieman leaf marking technique for Zostera marina growth and production assessment. Aquat. Bot. 47, 293–302.] to develop a relationship between sheath length and leaf growth in eelgrass, Zostera marina L., and we demonstrated that a simple, non-destructive method allows reliable calculation of eelgrass leaf growth (mg shoot−1 day−1) based on sheath length. We measured eelgrass sheath length and leaf growth for 18 months, from November 1999 to April 2001, at a site in Portsmouth Harbor on the border of New Hampshire and Maine, USA. Regression analyses showed a high coefficient of determination between sheath length and leaf growth, demonstrating that sheath length reliably reflected eelgrass leaf growth. We also showed that four seasonal measurements were sufficient to establish a significant relationship between sheath length and leaf growth. After a regression of sheath length and leaf growth has been established for a site, eelgrass sheath length can be measured in situ to accurately calculate leaf growth, eliminating both the need for destructive growth measurements and the need to mark and relocate plants