\u201cWe are losing tropical forests at an alarming rate, which is a serious concern because these ecosystems are essential for supporting wildlife, purifying the air, storing carbon and providing countless other [ecological] services,\u201d Gelambi says. \u201cOur ultimate goal is to contribute to the development of an effective strategy that uses fruit bat attraction to support forest restoration efforts.\u201d<\/p>\n
The new study provides a good initial step by demonstrating the potential of these attraction methods in the field, says Lays Parolin, an ecologist at the Pontifical Catholic University of Paran\u00e1. Parolin has conducted studies using essential oils as lures in Brazil but primarily on bats in captivity.<\/p>\n
\u201cWe have the theory that this can work, but there are still a lot of things we need to test in order make this bat attraction method more robust,\u201d she says.<\/p>\n
But do bat lures truly assist regrowth?<\/h2>\n
Proving that a natural or chemical attractant can lure bats or other seed-dispersing animals to a location is one thing. Determining whether or not that wildlife is sufficiently dispersing seeds to help regrow a forest is quite a different matter, requiring long-term observation.<\/p>\n
Scientists already know that seed dispersers, including fruit-eating bats, play a vital role in maintaining forest health. As bats fly place to place in search of food, they release feces often loaded with seeds \u2014 providing a source of new life and some fertilizer to stimulate first growth. Gelambi\u2019s dispersion study observed that pioneer species of trees were among the most frequently found in the seed traps set for bats.<\/p>\n
But whether or not the dispersed seeds actually germinate and contribute a lot to forest regrowth remains a crucial question, and one that hasn\u2019t been answered well by previous studies, says Karen Holl, a professor of environmental studies at the University of California, Santa Cruz. \u201cTo really have an impact, the seeds have to establish,\u201d she says. And that seeding needs to be documented and quantified.<\/p>\n
In her view, much more rigorous testing and evidence is needed to prove that fauna attraction methods contribute significantly to reforestation. Such experiments \u201cwould need to be [conducted] over a larger spatial scale and a longer time scale and measure recruitment. \u2026 That\u2019s really what [researchers] need to be doing to demonstrate these [lures] work.\u201d<\/p>\n
There are numerous barriers that newly dispersed seeds face before a degraded area can be transformed into a new forest. Among these challenges is the competition tree seeds face from grasses and other vegetation. Seed predation by birds and other animals is also a problem. Lures might work best when used in protected areas where ecological conditions favor regrowth, Holl says, but such long-term observations have yet to be done.<\/p>\n Holl argues that manually seeding or directly planting larger tree species could be a \u201cmuch better\u201d lure and restoration strategy. That conclusion is based on her own long-term project that focused on planting tree nuclei (or patches) on degraded land in Costa Rica. Those tree patches have proven effective at attracting seed dispersers, particularly birds and bats, over time. The patches have other advantages: They \u201cattract the fauna, shade out pasture grasses and overcome barriers to trees,\u201d she notes.<\/p>\n Parolin says her team is currently investigating seed recruitment effectiveness in Brazil, testing essential oil lures and monitoring how well new trees grow.<\/p>\n Gelambi agrees that the use of scents to attract seed dispersers is a technique still in its infancy. \u201cAdditional studies are needed to evaluate how effectively this approach works across various environments and over extended periods,\u201d she says, and work must be done to attract different species of bat. \u201cIt may take several years to validate these findings and develop strategies for real-world applications.\u201d<\/p>\n She suggests that maximizing reforestation may also require a mix of techniques depending on locale and situation, including chemical or natural attractants, plus the planting of trees that attract bats, birds and other seed dispersers.<\/p>\n Researchers in Brazil are planning a new project this year that will deploy essential oil lures in forested and degraded areas to determine if other seed-dispersing mammals, such as marsupials, are attracted to the test sites and \u201chopefully increase the diversity of seed dispersal,\u201d Parolin says.<\/p>\n \u201cIn the short term, our lures offer a practical application for bat researchers,\u201d Gelambi says. \u201cBy purchasing these [synthetic] molecules, researchers can attract bats to study their communities or address other ecological questions.\u201d<\/p>\n Parolin, L. C., Lacher, T. E., Bianconi, G. V., & Mikich, S. B. (2021). Frugivorous bats as facilitators of natural regeneration in degraded habitats: A potential global tool. Acta Oecologica, 111, 103748. doi:10.1016\/j.actao.2021.103748<\/p>\n Schubert, S. C., Zahawi, R. A., Oviedo\u2010Brenes, F., Rosales, J. A., & Holl, K. D. (2024). Active restoration increases tree species richness and recruitment of large\u2010seeded taxa after 16\u201318 years. Ecological Applications, 35(1). doi:10.1002\/eap.3053<\/p>\nCitations:<\/h2>\n