Restoring a critically endangered grassland orchid by co-planting to improve pollination and selecting sites based on pollinator availability.

In many geographic regions grasslands have been heavily cleared and degraded, which represents a challenge for translocating threatened flora back into these landscapes. As most plant species require animals for pollination, pollinators are potentially a key limitation for re-establishing populations. For the Critically Endangered orchid , we identify the pollinator(s), survey for pollinators at candidate translocation sites, test if remnant size affects bee species richness, and test if pollination rates can be enhanced through co-planting with rewarding plant species. We found that is visited by ten species of bee but is only effectively pollinated by two native species, sp. (Halictidae) and (Halictidae), and the introduced honeybee (Apidae). Interestingly, was responsible for the greatest number of pollinia removals and depositions. Pollinators of were not detected at some candidate translocation sites, with bee species richness and overall abundance significantly increasing with grassland remnant size. The pollination of was significantly enhanced through the presence of (Campanulaceae) within 30 cm of plants, but not (Asparagaceae) or (Asphodelaceae). We recommend that prior to conservation translocations of that pollinator surveys are undertaken, with preference given to larger grassland remnants. may serve to buffer against loss of native pollinators from remnant grassland but could have adverse effects on other native species. We show that co-planting with rewarding species may be an effective approach for improving pollination success of threatened orchids.