One key role of environmental monitoring is for filling knowledge gaps and improving predictive capabilities. However, a pre-occupation with long-term monitoring, means that we may be putting unnecessary resources into monitoring knowledge gaps that have already been filled. Once monitoring data provides a sufficiently high level of confidence in an ecological cause-effect relationship, resources should be reallocated to other conservation actions or monitoring objectives.
We used a case study of golden perch (Macquaria ambigua) spawning in response to elevated river discharge to demonstrate a method to determine when continued data collection yields little further understanding of an ecological relationship. We used three techniques to examine the contribution of additional data: (a) a historical 8-year monitoring dataset to evaluate the value of cumulative monitoring over time, (b) bootstrapping the existing dataset to verify whether the conclusions from (a) are robust across different datasets of different lengths, and (c) simulating synthetic monitoring data to validate the conclusion from (b).
Results from (a) indicate that the statistical model linking discharge to spawning only requires 4 years of data before additional data provides limited additional understanding. However, (b) and (c) suggest that 8-12 years of data might be necessary. With the case study monitoring having now run for more than 10 years, we conclude that understanding of the flow-spawning relationships is “good enough” to consider reallocating resources elsewhere.
This study demonstrates that monitoring might not need long time series to reach sufficient understanding of ecological cause-effect relationships. The idea of using resampled or synthetic monitoring data to assess the value of continued monitoring can be applied to other endpoints or other monitoring programs. This approach supports evidence-based decision making by informing when it is appropriate to review and potentially reallocate resources to other monitoring priorities, ultimately contributing to more efficient environmental management.