VARIAÇÃO NA ESTIMATIVA DE HERBIVORIA FOLIAR DE ACORDO COM DIFERENTES MÉTODOS TRADICIONAIS

Abstract

The correct and appropriate quantification of leaf herbivory is essential to understand its effects on plant ecology. Scientists evaluate leaf herbivory in two qualitative ways; in the Ranks method, herbivory is classified into classes (e.g., 0%, 1–25%, 26–50%, 51–75%, > 75% leaf damage) and in the Grid method, a transparent graph paper is superimposed on the leaves and herbivory is estimated by counting the squares. In this study we propose to make a comparison of leaf herbivory according to different participants and methods of measuring leaf herbivory (Ranks methods and Grids method). The central problem was to evaluate which of the approaches offered greater accuracy and efficiency. Leaves of Mussaenda philippica (Rubiaceae) were used as models and edited so that each one had a measure of leaf area loss. These sheets were presented to different participants. Each participant was askedto report herbivory values according to Ranks and Grids, and these values were compared with the real data. The results showed that the Grids method was more advantageous, because it is a fast method, with low cost and the herbivory values that were obtained are very similar to the values provided by digital methods.