Abstract

Impact of Invasive Rust Fungus Austropuccinia psidii on Ecosystem Integrity and Its Implications for Biodiversity Credit Markets

Sri RAHAYU, Rhomi ARDIANSYAH, KAHARUDDIN, WIDIYATNO

Department of Forest Biology, Faculty of Forestry, Universitas Gadjah Mada
sri.rahayu2013@ugm.ac.id

 The global spread of the invasive rust fungus Austropuccinia psidii (Myrtle rust) represents a critical biosecurity challenge to the biodiversity of Myrtaceae-rich ecosystems. This study investigates the multi-trophic disruptions caused by A. psidii and evaluates how these ecological impacts translate into financial risks within the emerging Biodiversity Credit markets. By analysing the decline in canopy cover, reproductive failure in keystone species, and the subsequent loss of niche habitats, we demonstrate, through a simulation, measurable erosion of ecosystem integrity using the Biodiversity Integrity Assessment (BII). Based on our findings, the invasion of A. psidii can directly reduce Ecological Integrity through species loss and ecosystem disruption, leading to the loss of its biodiversity value and impacting Biodiversity offsets, making it difficult to generate, sell, or maintain high-quality biodiversity credits. In addition, A. psidii is also indirectly related to carbon credits, which are sometimes bundled with biodiversity credits. Once established in natural settings, A. psidii is impossible to eliminate and poses an ongoing threat to the viability of biodiversity credits. Consequently, the risk buffer has to be incorporated into the model. This integration is essential for ensuring the integrity of credits and for long-term conservation outcomes in an era of increasing biological invasions.