Habitat restoration facilitates an ecological trap for a locally rare, wetland‐restricted butterfly

Abstract.  1. Ecological traps occur when organisms preferentially reproduce in low quality reproductive habitats because the co‐evolved cues associated with high quality habitat become re‐associated with low quality habitat due to anthropogenically mediated habitat changes. Although the proximate mechanisms underpinning nearly all empirical examples of ecological traps involve exotic species, agriculturalization, or artificial structures, habitat restoration may also facilitate ecological traps because it directly targets species assemblages with a long‐standing co‐evolutionary history. 2. In western Oregon, USA, a locally rare, wetland‐restricted population of the butterfly, Lycaena xanthoides , laid more eggs per host plant and more frequently oviposited on Rumex salicifolius growing in seasonally flooded, restored wetlands where survival is approximately seven‐fold lower than adjacent non‐flooded habitats. Outside of the restored wetlands, Rumex salicifolius is found almost exclusively in non‐flooded habitats adjacent to seasonally flooded wetlands. 3. In the non‐flooded habitat, host plant apparency appears to be reduced by tall, invasive exotic grasses ( Festuca arundinacea and Phalaris aquatica ), whereas host plants in seasonally flooded, restored wetlands were surrounded by low‐growing, native vegetation and bare ground, rendering host plants more physically conspicuous. The devaluing of higher quality host plants by overtopping exotic grasses immediately adjacent to conspicuous low quality host plants in restored wetlands appeared to facilitate an unintended ecological trap for Lycaena xanthoides via inaccurate host plant niche replacement. 4. Although there are few published examples of restoration traps, increased scrutiny of restored habitats will be necessary to determine how common and what type of situations facilitate ecological traps.