No place to call home: Distribution patterns of the tufted ghost crab, Ocypode cursor, populations in nature reserves, Israel, Eastern Mediterranean

The once plentiful population of the tufted ghost crab, Ocypode cursor, a legally protected species, suffered a steep decline along the densely populated Mediterranean coast of Israel. Here we assessed the effects of recreational disturbance on crab populations in three sandy shore nature reserves and adjacent bathing beaches with differing accessibility during the summers of 2020–2021, employing burrow counts and burrow opening diameter as proxies for population abundance and population size structure. A total 6270 burrows were identified, counted and their opening diameter measured during the study period. The number of burrows was greatest close by the waterline and diminished landwards; this landwards decline was notable in the smallest burrows (<20 mm), representing the youngest population fraction. Comparison of population abundance between the surveyed nature reserves and adjacent bathing beaches revealed greater numbers in the former. However, a pronounced postweekend reduction in the number of burrows was apparent in nature reserves during both survey years, across sites and months and clearly indicates elevated recreational activity. The number of burrows in the nature reserve nearest to main population centres and abutting a popular bathing beach was smaller compared with the peripheral nature reserves. We observed no postsunrise activity of adult crabs, though in strictly access-restricted beaches, crabs were active diurnally. We thus suggest that the crabs shifted their diel activity patterns as avoidance response to chronic anthropogenic disturbance, enduring a forced curfew and a temporal habitat loss. If the sandy nature reserves are to function as true refugia for the tufted ghost crab, restorative management is to include significant conservation and mitigation intervention measurements/actions.