Neoliberalization of Conservation

I read with great interest the article by Kelm et al. (2008) proposing bat roosts as a method to enhance recovery of tropical forests because new strategies to facilitate forest regeneration in the vast areas of degraded agricultural lands in the tropics are urgently needed. The authors present convincing data that artificial bat roosts successfully attract several bat species and significantly enhance seed rain in remnant and intact tropical forest. Kelm et al., however, frame the article around the question of whether bat roosts facilitate tropical forest recovery in degraded lands and make strong conclusions in support of this premise, conclusions that are not well substantiated by their data. First, the authors suggest that “artificial roosts may act as nuclei for recovery in a similar fashion to isolated trees in abandoned pastures,” but they did not put isolated bat roosts in abandoned pastures or other agricultural lands that have minimal tree structure. Rather they put the roosts in “small forest fragments (<3 ha) or tree stands in agricultural habitat. ” Microclimate, food resources, and predation risk in open pasture are quite different in small forest remnants, and the characteristics of open pasture would likely substantially affect bat colonization of roosts (e.g., Evelyn & Styles 2003) and associated seed dispersal. Second, it is likely that bats flying between roosts in different small fragments would enhance seed rain in the nearby areas of open pasture, given that Kelm et al. (2008) recorded extensive bat movement among fragments and bats often defecate during flight (reviewed in Muscarella & Fleming 2007). Nonetheless, the authors presented no data demonstrating that bat roosts increased seed rain in the adjacent pasture or that such an increase would be of a sufficient magnitude to enhance forest regeneration in the adjacent pastures. Seed rain in open agricultural lands is much lower than in forest remnants or tree clusters (reviewed in Holl 2002); therefore, open pastures are where augmented seed rain is most critical to facilitation of forest recovery, rather than where bat roots were placed. Finally, Kelm et al. assume elevated seed rain will result in higher establishment of woody species. Lack of seed dispersal is only one of many obstacles to tropical forest recovery in degraded habitats (reviewed in Holl 2002), so it is impossible to conclude whether enhanced seed rain will facilitate forest recovery without measuring forest regeneration (i.e., seedling establishment and survival). Indeed, my own research testing the use of bird perches to facilitate tropical forest recovery in abandoned pasture shows that increased seed rain does not translate into higher woody seedling establishment, likely because of seed predation and seedling competition with pasture grasses (Holl 1998). The small-seeded, lightdemanding species Kelm et al. primarily recorded in seed traps below roosts have extremely low probabilities of establishment in abandoned pastures (Hooper et al. 2002). I agree that bat roosts may be a promising tool for tropical forest restoration, but roosts need to be tested in that context and forest regeneration must be measured before this claim can be made. Because the use of bat roosts is a novel and enticing restoration idea, the take-home points of this article have already been disseminated to the restoration community through the Society for Ecological Restoration International (9 April RESTORE electronic newsletter; http://archive.constantcontact. com/fs052/1101952074862/archive/ 1102052428807.html). My concern is that practitioners will assume this strategy for tropical forest restoration in abandoned agricultural lands has been tested, when it has not.