SSNdesign -- an R package for pseudo-Bayesian optimal and adaptive sampling designs on stream networks

TL;DR

SSNdesign is an R package that applies pseudo-Bayesian optimal and adaptive sampling designs to stream networks, improving data collection efficiency for freshwater monitoring and conservation.

Contribution

The paper introduces SSNdesign, a novel open-source R package that addresses statistical challenges in geostatistics on stream networks for optimal and adaptive sampling.

Findings

Optimal and adaptive designs outperform random and spatially balanced designs

Case studies demonstrate improved efficiency in real-world data collection

The package facilitates better decision-making in freshwater monitoring

Abstract

Streams and rivers are biodiverse and provide valuable ecosystem services. Maintaining these ecosystems is an important task, so organisations often monitor the status and trends in stream condition and biodiversity using field sampling and, more recently, autonomous in-situ sensors. However, data collection is often costly and so effective and efficient survey designs are crucial to maximise information while minimising costs. Geostatistics and optimal and adaptive design theory can be used to optimise the placement of sampling sites in freshwater studies and aquatic monitoring programs. Geostatistical modelling and experimental design on stream networks pose statistical challenges due to the branching structure of the network, flow connectivity and directionality, and differences in flow volume. Thus, unique challenges of geostatistics and experimental design on stream networks necessitates the development of new open-source software for implementing the theory. We present SSNdesign, an R package for solving optimal and adaptive design problems on stream networks that integrates with existing open-source software. We demonstrate the mathematical foundations of our approach, and illustrate the functionality of SSNdesign using two case studies involving real data from Queensland, Australia. In both case studies we demonstrate that the optimal or adaptive designs outperform random and spatially balanced survey designs. The SSNdesign package has the potential to boost the efficiency of freshwater monitoring efforts and provide much-needed information for freshwater conservation and management.