Modeling Taiwan’s landscape evolution

Mountain regions are globally recognized as biodiversity hotspots. Taiwan is a vivid example, offering an ideal landscape to study the interplay between mountain building and biodiversity. The island resulted from an active arc-continent collision that created a high-relief landscape. The high rates of tectonic uplift, shortening, and extension together with its location in the typhoon belt with high rates of precipitation and erosion results in some of the highest rates of landscape change globally. The short tectonic history and extensive tectonic and geomorphic research provide an opportunity for exploring how mountain building has influenced the island's biodiversity. In this study, we use the landscape evolution model ‘Divide and Capture’ (DAC) to simulate Taiwan’s topography from the onset of uplift to the present day. Landscape evolution modeling predicts the river network patterns, erosion rates, and physical geography in response to tectonic and climatic forcing. We subdivide Taiwan into four major geological domains (Western Foothills, Hsuehshan Range, Central Range, and the extensional Ilan back-arc) and apply horizontal and vertical velocities to each domain subject to a sea level boundary condition that changes in time to simulate the island shape. The resulting model is constrained to fit the exhumation history estimated from low-temperature thermochronometry. Cooling ages from apatite and zircon fission track and helium dating are converted to erosion rates using a thermal model (GLIDE), and used for calibration of the landscape evolution model. The model improves our understanding of Taiwan’s geomorphic history and lays the groundwork for future studies on the interconnection between tectonics, landscape evolution, physical geography, and biodiversity.