Lemurs are rainforest gardeners. By feeding on fruits and passing seeds in their feces, species of this highly-endangered primate group spread seeds throughout the forest. As Madagascar's primary seed dispersers, lemurs help sustain biodiversity and healthy plant communities throughout forest landscapes. Importantly, they can also encourage regeneration in disturbed habitats. However, some lemurs are more effective than others at promoting plant growth and survival. The effectiveness (quality and quantity) of seed dispersal interactions is highly variable and context-dependent. Seed dispersal effectiveness may depend on lemur species, plant species, and/or characteristics of both the lemurs and the plants.
Deep in COMATSA (a community-managed protected area in northeastern Madagascar), our team has been searching for lemurs up and down steep mountain trails. Our goal is to better understand what characteristics influence the effect of lemur seed dispersal on plant germination. We are also eager to learn about what implications these effects have for forest regeneration. So, upon encountering a group of lemurs on the trail, we watch closely and cross our fingers for for a bowel movement. Luckily, after a morning of feasting on rotro seeds, the lemurs typically comply. Then, the search is on. Finding a fecal sample on the forest floor can be quite a challenge, but my teammates are diligent and skilled, and often return to camp victorious.
Back at camp, we sort through samples and extract the seeds. After seed measurement and identification, we place any seeds in Petri dishes, returning every few days to assess whether or not the seed has germinated. We conduct parallel germination experiments with control seeds (seeds directly from trees or the forest floor) so we can compare germination rates and times between lemur-passed and control seeds. We are also interested in determining if there are differences in germination rates of seeds passed by the two diurnal, primarily frugivoruous lemurs in the study site (Eulemur rubriventer and Eulemur albifrons), as well as differences across plant species and sizes. The lemur seed dispersal interactions are complex and fascinating. As an added bonus, we plant germinated seeds to aid in local reforestation efforts!
While I am back at Duke University in Durham, North Carolina, data collection is ongoing in Madagascar, led by Project Manager Zico Zandry and Assistant Project Manager Telesy Feno. Once the fieldwork is complete, we are all excited to analyze the data and add to the ever-deepening story of lemur rainforest gardeners.
After a successful morning of lemur fecal sample collection.
Tiamanana, Dom, and Telesy checking for germination.