An allometric method for the projection of eelgrass leaf biomass production rates

et al. 2014

lajar

ABSTRACT. Restoration of eelgrass Zostera marina meadows from harmful anthropogenic influences has made it essential to evaluate these efforts by using non-destructive assessments. Allometric methods provide a convenient framework for the derivation of reliable indirect assessments of leaf biomass and leaf growth of eelgrass. Invariance of the involved parameters could grant truly nondestructive assessments because previously fitted values could be used to produce consistent estimations. In order to explore this property we analyzed data from two natural eelgrass populations in the East Pacific (México), as well as populations in the West Pacific (two natural in Korea and one mesocosm in Japan). When we compared observed leaf growth rates with those projected allometrically by using parameter values fitted at different sites, we found that only parameter values fitted at sites within the same geographical region can produce consistent results. Therefore if this restriction holds previously fitted parameters can indeed be used to produce reliable non-destructive assessments of eelgrass leaf growth rates. Keywords: Zostera marina, foliar growth, eelgrass meadow, allometric modeling, restoration evaluation.Efectos de la variabilidad paramétrica en la obtención de tasas de crecimiento foliar en Zostera marina L. mediante métodos alométricos RESUMEN. La restauración de praderas de Zostera marina que han sido dañadas por influencia antropogénica, ha hecho necesaria la evaluación de estos esfuerzos mediante métodos no destructivos. Las metodologías alométricas proporcionan un marco formal que favorece la obtención de estimaciones indirectas de biomasa y tasas de crecimiento foliar. La invariancia de los parámetros asociados asegura la obtención de técnicas de estimación no destructiva de gran confiabilidad, puesto que, parámetros previamente ajustados podrían usarse para producir estimaciones consistentes. Para investigar la existencia de esta propiedad se analizan datos provenientes de dos poblaciones naturales de Z. marina en el Pacífico oriental (México) así como también poblaciones en el Pacífico occidental (dos naturales en Corea y una cultivada en laboratorio en Japón). Al comparar valores observados de tasas de crecimiento foliar con aquellos obtenidos alométricamente, utilizando parámetros ajustados en sitios indistintos, se observó que únicamente cuando los parámetros provienen de una región geográfica equivalente se pueden producir resultados consistentes. Por lo tanto, tomando en cuenta esta restricción parámetros alométricos previamente ajustados pueden, en efecto, producir evaluaciones no destructivas y fiables de tasas de crecimiento de las hojas de Z. marina.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The effect of parameter variability in the allometric projection of leaf growth rates for eelgrass (Zostera marina L.)

Solana-Arellano

et al. 2014

lajar

“…In the other hand, we need to be aware that since the power functions involved in allometric approaches are highly sensitive to parameter uncertainty we require consistent estimations of blade length or area [10]. Therefore, when we estimate eelgrass leaf area, using digital imagery in combination with allometric proxies, we must be aware that image noise could certainly reduce the accuracy of estimates.…”

Section: Discussionmentioning

confidence: 99%

“…Favorably, the conspicuous growth form of eelgrass makes it possible to introduce proxies that allow assessments while avoiding invasive interference. Moreover, estimations of leaf biomass or productivity in eelgrass can be efficiently obtained using allometric alternatives, which state these variables in terms of leaf length or area [9, 10]. But even though leaf architecture in eelgrass makes length a consistent descriptor of area, allometric models that express leaf biomass in terms of linked area perform relatively better than those involving leaf length as an independent variable.…”

Section: Introductionmentioning

confidence: 99%

“…These variables provide convenient estimations of the corresponding blade area a , through the leaf length times width proxy [1]. If we used the symbol o as a subscript to represent observed values for the above named variables, then estimations of leaf area obtained through this proxy are given by

\begin{matrix} a_{o} = l_{o} \cdot h_{o} \end{matrix}

which combined with allometric methods could simplify assessments of eelgrass leaf biomass and productivity [9, 10]. …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Method for Calculating the Area ofZostera marinaLeaves from Digital Images with Noise Induced by Humidity Content

The Scientific World Journal

2014

Despite the ecological importance of eelgrass, nowadays anthropogenic influences have produced deleterious effects in many meadows worldwide. Transplantation plots are commonly used as a feasible remediation scheme. The characterization of eelgrass biomass and its dynamics is an important input for the assessment of the overall status of both natural and transplanted populations. Particularly, in restoration plots it is desirable to obtain nondestructive assessments of these variables. Allometric models allow the expression of above ground biomass and productivity of eelgrass in terms of leaf area, which provides cost effective and nondestructive assessments. Leaf area in eelgrass can be conveniently obtained by the product of associated length and width. Although these variables can be directly measured on most sampled leaves, digital image methods could be adapted in order to simplify measurements. Nonetheless, since width to length ratios in eelgrass leaves could be even negligible, noise induced by leaf humidity content could produce misidentification of pixels along the peripheral contour of leaves images. In this paper, we present a procedure aimed to produce consistent estimations of eelgrass leaf area in the presence of the aforementioned noise effects. Our results show that digital image procedures can provide reliable, nondestructive estimations of eelgrass leaf area.

The length‐times‐width proxy for leaf area of eelgrass:criteria for evaluating the representativeness of leaf‐width measurements

Solana-Arellano

et al. 2011

Aquatic Conservation

Self Cite

ABSTRACT1. Conservation and remediation projects for Zostera marina populations require easy and economical methods for non-destructive approximations of leaf area. Allometric models provide a reliable approach for estimating biomass in terms of leaf area, and the length-times-width proxy for leaf area is widely used.2. Although leaf length of Z. marina can be unambiguously determined as the span from the ligula to the tip, different methods have been reported for obtaining representative measurements of leaf width.3. Using allometric models and eelgrass leaf-growth properties we derived criteria based on regression equations, for the assessment of the representativeness of leaf width as a determinant of leaf area. In comparison with other estimations reported in the literature, width measurements taken at the midpoint of the leaf produced the most consistent proxy values for leaf area of eelgrass.