Description
Predators serve strong ecological roles in structuring ecosystems by both eating prey (consumptive effects) and scaring prey (non-consumptive effects). In the Hampton River, predatory mud crabs induce defensive morphologies in the Eastern oyster (Crassostrea virginica), where oysters exposed to predator cues tend to reallocate energy away from growth and reproduction and towards shell strength. Here, we revisit the efforts of a long-term predator exclusion experiment comparing mesopredator abundance and inducible defenses in oyster spat within the Hampton River. Predator exclusion cages of various sizes were deployed in the Hampton River in the summers of 2024 and 2025 and collected after 8-12 weeks. Oyster spat recruitment was counted on disarticulated oyster shells from each cage, and individual spat were subjected to crushing force tests using a Kistler force penetrometer and charge amplifier. Fauna (mesopredators) collected from cages were identified, counted, and measured to assess community composition. Preliminary results on degraded urban reef sites in 2024 showed no correlation between mesopredator abundance and spat shell strength. However, we hypothesize that this correlation will be more prominent after restoration efforts in 2025 have begun to impact physical reef complexity. While data from 2025 is currently in analysis, our results thus far suggest that top-down community regulation is fundamentally distinct between low complexity and restored human-dominated landscapes, resulting in potentially novel species interactions and food webs. More work is needed to understand species interactions during the intermediate phase of restoration as well as causes for irregular defensive responses of oysters within human-dominated land.