Ecological Preferences and Current Suitable Areas of the Tropical Fruit Stelechocarpus burahol (Blume) Hook.f. & Thomson in Java
Abstract
Stelechocarpus burahol (Blume) Hook.f. & Thomson is a fruit plant historically associated with Java. Although several studies have revealed its potential, the species continues to decline. Therefore, this study aimed to explore the ecological preferences through Principal Component Analysis (PCA) using RStudio 2023.12.1 and to predict current suitable areas, referring to suitability predicted using 1970-2000 WordClim data for S. burahol in Java using MaxEnt version 3.4.4 as a guideline for conservation planning. Field surveys were conducted in 16 regencies from June to December 2024, and 54 presence points were recorded. Ecological preferences were evaluated using PCA based on microclimatic variables measured in the field. Among these, air temperature, relative humidity, light intensity, and elevation were the most influential microclimatic factors explaining habitat variation. Meanwhile, the importance of environmental variables in the prediction model was assessed using Pearson's correlation and the Jackknife test. Therefore, seven out of 32 environmental variables were selected. The model achieved a mean AUC of 0.885 ± 0.035, indicating good predictive performance. The most influential predictors were isothermality, mean diurnal temperature range, mean temperature of the driest quarter, precipitation of the wettest month, elevation, and solar radiation intensity in November and March. Highly suitable areas were concentrated in Cilacap, Banyumas, Purbalingga, Banjarnegara, Kebumen, Purworejo, Batang, Klaten, Tulungagung, Blitar, Kediri, Jember, and Banyuwangi. These findings provide an ecological basis and conservation assessment under current environmental conditions.
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