# Exploratory Assessment of Short-Term Antecedent Modeled Flow Memory in Shaping Macroinvertebrate Diversity: Integrating Satellite-Derived Precipitation and Rainfall-Runoff Modeling in a Remote Andean Micro-Catchment

## TL;DR

This study explores how short-term changes in streamflow affect aquatic insect diversity in a remote Andean catchment using satellite data and modeling.

## Contribution

The study introduces a practical method for analyzing flow-ecology relationships in ungauged, remote catchments using modeled streamflow and satellite data.

## Key findings

- Biological communities respond more to cumulative flow conditions than to single flow events.
- Taxonomic diversity reacts faster to flow changes than functional diversity.
- Cumulative negative flow changes are consistently linked to taxonomic diversity.

## Abstract

Studying river flow effects on aquatic ecosystems is challenging in isolated mountain regions where sustained water data are lacking. Small Andean headwater streams are a prime example: they are crucial for biodiversity but are seldom studied because of their remote locations. This study integrates satellite rainfall data, hydrological models, and field observations of aquatic insects to investigate how short-term streamflow fluctuations influence biological communities. We focused on a small, pristine mountain catchment in southern Ecuador and analyzed how recent flow conditions over days to weeks were related to changes in the diversity of aquatic organisms. Our results show biological communities respond more strongly to accumulated flow conditions over time than to single flow events. We also found that traditional measures of species diversity reacted more quickly to changes in flow than functional characteristics of the community, which reflect slower ecological processes. By using modeled streamflow, this study shows a practical and transferable approach for investigating flow–ecology relationships in rivers where direct monitoring is not available. The findings are valuable for improving ecological assessments, conservation planning, and water management in remote freshwater systems where monitoring data are scarce.

Estimating runoff in ungauged catchments remains a major challenge in hydrology, particularly in remote Andean headwaters where limited accessibility and budgetary constraints hinder the long-term operation of monitoring networks. This study integrates satellite-derived rainfall data, hydrological modeling, and benthic macroinvertebrate diversity analysis to explore how short-term antecedent flow conditions relate to temporal variation in community structure. The research was conducted in a pristine 0.26 km2 micro-catchment of the upper Collay basin (southern Ecuador). Daily simulated discharge was used to compute antecedent flow descriptors representing short-term variability and cumulative changes in stream conditions, which were related to taxonomic (i.e., H = Shannon diversity, E = Pielou evenness, and D = Simpson dominance) and functional indices (i.e., Rao = Rao’s quadratic entropy, FAD1 = Functional Attribute Diversity, and wFDc = weighted functional dendrogram-based diversity) using Generalized Additive Models. Results showed progressively higher hydrology–biology associations with increasing antecedent flow integration length, suggesting that biological variability responds more strongly to cumulative than to instantaneous flow conditions. Among hydrological descriptors, the cumulative magnitude of negative flow changes was consistently associated with taxonomic diversity. H and E showed more coherent and robust patterns than functional metrics, indicating a faster response of community composition to short-term hydrological variability, whereas functional diversity integrates slower ecological processes. While based on modeled discharge under severe hydrometeorological data limitations, this study provides a practical ecohydrological starting point for identifying short-term hydrological memory signals potentially relevant to aquatic biodiversity in ungauged headwater systems.