LAUSR

Human pressures are pervasive in coastal ecosystems, but their effect magnitudes are masked by methodological limitations. Government lockdowns associated with the global COVID-19 pandemic can address this gap since lockdowns are effectively manipulations of human presence in ecosystems at scales unachievable otherwise. We illustrate this using a study on shorebirds in an urban South African sandy beach ecosystem. Data collected prior to (2019) and during the COVID-19 (2020) pandemic indicated an inverse relationship between shorebird and human numbers, but this was stronger in 2020. In 2020, human exclusion resulted in a six-fold increase in shorebird abundance relative to 2019. Following easing of lockdowns, shorebird abundance declined by 79.6% with a 34.1% increase in human density. Our findings highlight the sensitivity of shorebirds to recreational disturbance, the potential for current methodological approaches to underestimate repercussions of disturbance and the capacity for COVID-19 lockdowns to refine understanding of human-induced stress in ecosystems.