Assessment Framework of Ecosystem Services and Functions of Interconnected Small WaterBodies in Slopeland

Different types of water bodies, such as streams, creeks, irrigation ponds, and paddies, form networks in low-elevation mountainous areas, referred to as Interconnected Small Water Bodies in Slopeland (ISWBS) in the context of Taiwan. Little is known about the ecosystem functions and conservation potential of ISWBS, and an assessment framework is proposed using an integration of remote sensing and field survey data. We analyze whether network characteristics, node characteristics, and landscape factors impact ecological functions and estimate the services related to sediment reduction, agricultural production, and biodiversity that ISWBS provides.

In this preliminary study, we focused on irrigation and natural ponds as important nodes within ISWBS. Monitoring stations were established to record the micro-climate factors of the ponds, and surveys of benthic macro-invertebrates were conducted in 2024. Using a framework of functional feeding groups, the ponds are categorized based on the relative abundance of collector-gatherers, which significantly affect the results of ordination. Community analysis shows little and non-significant relationships between community composition and environmental factors, namely variations in water depth, landscape indices, and irrigation use. However, some factors, such as water depth variation during low depth periods, total edge length, and canal connection, show potential to contribute to future analyses.

Regarding the remote sensing analysis, we find that the distance between nodes has decreased over the past 40 years. Nevertheless, no biodiversity records are available to determine the impact of landscape change. The effects of changing network characteristics on community composition and functional groups are unclear due to insufficient sampling of biodiversity data. Further biodiversity sampling and the study of network characteristics are critical to determine how ISWBS functions in ecosystem processes, especially for sediment detention and nutrient cycling at a landscape scale.