Twenty‐nine years of monitoring data illustrate variable aquatic insect populations correlated with predators and hydrologic variation in the Everglades

Declining insect populations have received a lot of attention in recent years. While most of the headline‐grabbing declines have been in terrestrial ecosystems, few studies have reported changes in freshwater systems, and patterns reported for freshwater insect populations have been mixed. Here, we examine data of aquatic insects collected from two biological monitoring programmes in the subtropical Florida Everglades. These monitoring programmes were established to track the populations of fishes and invertebrates important to larger predators (wading birds and alligators) iconic to the freshwater Everglades at a time when (mid‐1990s to 2000s) efforts towards ecosystem restoration began. Here, our goals were to assess overall trends and drivers of insect densities while examining how conclusions drawn from the datasets depend on the spatial and temporal scope of the data analysed. The multi‐season (24 sites sampled 5×/year 1996–2025) 29‐year dataset indicated mostly net gains to insect densities, while the more spatially expansive single season (146 sites sampled 1×/year 2005–2024) 20‐year dataset indicated a mix of taxon‐specific trends (declines, no changes, increases). Variable population densities could be partially attributed to hydrologic variation in the seasonally wet/dry wetlands, as the frequency of dry‐downs has generally decreased over the past decade and most common taxa responded well to longer hydroperiods. Most insect densities were negatively related to fish richness but positively related to the total density of small fishes. Invasion of Asian swamp eels ( Monopterus spp.), which have altered fish and decapod assemblages, may also be partly responsible for increasing insect populations; restricting the 29‐year dataset to years prior to swamp eel invasion indicated declines for most taxa. The different conclusions from two different datasets highlight an important finding that details of the monitoring dataset can affect the evidence and interpretations of trends. Our results illustrate the value of systematic long‐term monitoring programmes for understanding changing insect abundances as they relate to changing environmental conditions, whether natural or human‐induced. This study also shows that common insect populations can be resilient and quickly rebound when conditions change, as is currently occurring in the Everglades.