Evaluating restored ecosystem functions in the rehabilitated watershed in Manolo Fortich, Bukidnon, Philippines using landscape function analysis

Catherine de Luna; Enrique Tolentino; Wilfredo Carandang; Margaret Calderon

Catherine C. de Luna Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management, College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines
Enrique L. Tolentino, Jr. Institute of Renewable Natural Resources, College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines
Wilfredo M. Carandang Institute of Renewable Natural Resources, College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines
Margaret M. Calderon Institute of Renewable Natural Resources, College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines

Keywords: Calliandra, infiltration, landscape function analysis, nutrient cycling, stability

Abstract

Landscape Function Analysis (LFA) was employed in assessing the restoration of ecosystem functions in a degraded watershed along the southern portion of Mt. Kitanglad in Manolo Fortich, Bukidnon, Philippines, rehabilitated using Calliandra calothyrsus Meissn. This part of the Mt. Kitanglad Mountain Range is mostly degraded with unproductive grasslands and massive areas planted with monocrop of corn. The LFA indices for stability, infiltration, and nutrient cycling were determined in four seral stages of Calliandra: RA1 (1-year-old Calliandra), RA4 (4-year-old Calliandra), RA6 (6-year-old Calliandra), and RA12 (12-year-old Calliandra) and were compared with grassland (GL) and adjacent secondary growth forest (SF). Results showed that indices of stability, infiltration, and nutrient cycling were highest in the SF at 84.7, 79.4, and 79.8, respectively. Indices for the RA12 approach that of the SF have values of 84.5, 65.3, and 64.4 for stability, infiltration, and nutrient cycling, respectively. All indices for the different seral stages (RA1, RA4, and RA6) were lower than SF, GL, and RA12. Stability index for the rehabilitated areas was in order RA12>RA4>RA6>RA1. Infiltration and nutrient cycling indices were in order RA12>RA6>RA4>RA1. LFA was a useful tool in utilizing Calliandra as a pioneer species in watershed rehabilitation to hasten the biogeochemical functions of rehabilitated sites and approaches the ecosystem functions of the SF with an increase in age compared to when no rehabilitation efforts were conducted as in the GL ecosystem.