Abstract

Farmlands occupy more than half the inhabitable Earth, sustaining much of the planet's wildlife. Many farmland species have not been able to adapt to the severely anthropogenically modified environments of modern agricultural lands. The northern lapwing has declined steadily in most countries since the 1980s. Reports of sudden, inexplicable local collapses are reported, where the population is all but gone within a decade, suggest that observed slow regional population declines could just be the result of many small population implosions spread out in time and space. With the northern lapwing as model species, the proposed trap-implosion theory unveils how increases in the proportion of intensively farmed cropland, act as an ecological trap, triggering local population implosions. The simulations show the ratio of high-to-low-quality breeding habitat to be the main trigger. This demonstrates that expansion of modern farmlands alone, rather than loss of natural habitat, may cause population collapse. The rate of habitat-area changes, declines in yearly survival, and breeding success mainly affect the timing of the implosion, but not its pace. Observations of local lapwing-population collapses suggest that the declines of many farmland species, especially farmland bird species, may be the accumulative result of local trap implosions. A conservational focus on farming practices and preserving or improving high-quality habitat may explain why the mechanism of ecological-trap-induced implosions have gone unnoticed, and why farmland-bird conservation measures have largely failed.