Strong relationship between qualitative Rapid Assessment Forms and quantitative indices used to assess the ecological quality of forests in Northland, New Zealand

Abstract

Introduction: Payment for Ecosystem Service (PES) projects typically require that results from monitoring and reporting are verified to empirically prove that interventions pass the test of additionality. Generally, PES monitoring and reporting assessment frameworks used by community groups or landowners are qualitative while verification methodologies use established quantitative metrics (e.g. forest structural data assessed using standardized techniques). However, few studies have systematically tested the degree of correlation between qualitative and quantitative metrics. Objectives: The study aimed to understand whether rapid assessments can accurately gauge forest health when considering various pressures and management responses, and whether this could be tested and evaluated through reference to structural indices. Methods: We developed a Rapid Assessment Form (RAF) for application as a monitoring and reporting tool tailored to forests in Northland, New Zealand. The RAF was tested across forest fragments on Pāmu farms and reference forests which exhibit a range of attributes, encompassing a wide spectrum of ecological quality. We collected quantitative data at the same locations and used a revised Index of Structural Complexity (rCI) as a proxy for “quality” to evaluate and verify RAF outcomes. Results: Results show a strong, significant coefficient of determination relationship between RAF scores and the rCI (RAF Part B ecological “state” r² = 0.993, RAF overall r² = 0.838). Conclusions: The RAF demonstrated applicability as a robust, reliable means of monitoring and reporting ecosystem quality and the rCI as a useful verification tool, therefore establishing a platform for wider incorporation within PES projects.