Dietary plasticity of Formosan hares in lowland ecosystems: a comparison of riverbank and farmland grasslands

Abstract The Formosan hare ( Lepus sinensis formosus ) is an important herbivore in lowland ecosystems of Taiwan, and understanding its diet and foraging strategies is essential for evaluating its ecological role and managing potential human–wildlife conflicts. This study applied DNA metabarcoding to investigate how different land cover types (riverbank grassland and farmland) influence dietary composition and to assess whether the Formosan hare's foraging behavior is selective or opportunistic. We collected fecal samples from riverbank grasslands and farmland grasslands in the Bazhang River basin of the Chiayi area in southwestern Taiwan. These sampling sites were systematically paired with quadrat‐based vegetation surveys conducted at the corresponding locations. We identified plant components in fecal samples using next‐generation sequencing (NGS) with trnL primers, and used Chesson's selectivity index to evaluate resource use and foraging selection relative to plant availability in the environment. We identified 36 plant families, indicating that the Formosan hare has a broad dietary spectrum. Land cover type influenced dietary composition: diets in riverbank grasslands were dominated by Fabaceae (47.7%), whereas those in farmland grasslands shifted toward heavy use of Poaceae (74.4%). The analysis further demonstrated consistent and strong selection for tall reed ( Phragmites karka ) and the invasive species white leadtree ( Leucaena leucocephala ). Notably, the use of cultivated crops was extremely low (<0.1%), suggesting that hares foraging in farmlands still rely primarily on surrounding graminoid vegetation rather than crops. Overall, the results indicate that the Formosan hare is a generalist herbivore capable of adjusting its diet in response to habitat conditions, with minimal impact on agricultural production. However, the substantial consumption of white leadtree, which contains the toxic compound mimosine, raises concerns about a potential food‐trap effect driven by invasive plant expansion, and its long‐term implications for hare population health warrant further investigation.