Extensive chameleon mortality in mechanized harvest of grapes suggests that wildlife biodiversity in the agricultural matrix may be a double-edged sword

The global pervasiveness of agriculture and its profound effects on biodiversity increasingly mandate developing sustainable agricultural methods to support healthy ecosystems within agricultural landscapes. However, increasing the attractiveness of agricultural landscapes for wildlife may negatively impact biodiversity if animals or their reproduction are adversely affected in such habitats. While the effects of agricultural practices were investigated across various crop types and wildlife species, reptiles remain largely overlooked. Additionally, although reptiles in croplands were monitored throughout the farming season, little attention has been directed towards the effects of harvest at the season’s end. To illustrate the potential impacts of mechanical harvest on wildlife in permanent crops, we present a case-study concerning reptiles in vineyards. We scanned the waste of a medium-sized winery over four nights and found 105 reptiles, 69% of them chameleons. Though chameleons are considered carnivorous, approximately half had consumed grapes, potentially attracted by them. Vineyards, like many crops, offer resources including sugar, moisture, and shelter, likely attracting many wildlife species. However, mortality during mechanical harvest may be high, potentially rendering such crops an ecological trap. For chameleons the effects may be particularly devastating, as harvest closely precedes the egg-laying season. While our case study focuses on reptiles in vineyards, its implications extend to many species in croplands. Ultimately, ecological traps affect biodiversity by attracting animals to habitats in which their fitness is impaired. While preference has been widely discussed in determining trap severity, our case study highlights that considering the trap’s fitness impact is also crucial. • Agricultural landscapes may attract wild animals while increasing their mortality • Studies of biodiversity in agriculture must account for the effects of harvest • Chameleons are likely attracted to vineyards but killed just before reproducing • Agricultural methods and life history interact to determine ecological trap severity • Ecological trap severity is affected both by preference and by fitness effects