An international study on 47 species of monkeys and lemurs has shown how climate change and deforestation interfere with the primates' lifestyle. The influence of environmental changes leads many of these animals, who normally live in trees, to change their habits, pushing them down to the ground, where they are more exposed to risk factors such as lack of food, predators, the presence of humans and domestic animals.

The study, published in the journal PNAS (The Proceedings of the National Academy of Sciences), was co-ordinated by Timothy Eppley, a researcher at the San Diego Zoo Wildlife Alliance (SDZWA), and saw the extraordinary worldwide collaboration of 118 co-authors from 124 different institutes, including Luca Santini of Sapienza University of Rome, who co-authored and supervised the work. The results are based on approximately 150,000 hours of observation data on 15 species of lemurs and 32 species of monkeys at 68 sites in the Americas and Madagascar.

The research evaluates the influence of biological characteristics, environmental context and human actions on arboreal primates' time spent on the ground. The study found that species that consume less fruit and live in large social groups are more likely to abandon the arboreal lifestyle. One can, therefore, define these conditions as a kind of 'pre-adaptation' to what the future life of these animals may be. The study also showed how temperature and forest degradation drive primates to use the terrestrial layer more. Consequently, in a fragmented habitat disturbed by humans and offering scarce food resources, only primate populations that have a more diverse diet and live in large groups can adapt more easily to a terrestrial lifestyle.

The study also found that primate populations closer to human infrastructure are less likely to come ashore: "Our results," says Luca Santini of Sapienza University, "suggest that human presence, often a threat to primate conservation, may interfere with their natural adaptability to global change".

Transition situations from an arboreal to an earthy lifestyle have occurred in the past.

The concerns that led scholars to initiate a study of this magnitude stem from the rapidity with which climate change and human intervention occur. That would require for less adaptable species, rapid and effective conservation strategies to ensure their survival.

References:

Factors influencing terrestriality in primates of the Americas and Madagascar - Eppley T.M., Hoeks S., Chapman C.A., Ganzhorn J.U., Hall K., Owen M.A., Adams D.B., Allgas N., Amato K.R., Andriamahaihavana M., Aristizabal J.F., Baden A.L., Balestri M., Barnett A.A., Bicca-Marques J.C., Bowler M., Boyle A.S., Brown M., Caillaud D., Calegaro-Marques C., Campbell C.J., Campera M., Campos F.A., Cardoso T.S., Carretero-Pinzón X., Champion J., Chaves O.M., Chen-Kraus C., Colquhoun I.C., Dean B., Dubrueil C., Ellis K.M., Erhart E.M., Evans K.J.E., Fedigan L.M., Felton A.M., Ferreira R.G., Fichtel C., Fonseca M.L., Fontes I.P., Fortes V.B., Fumian I., Gibson D., Guzzo G.B., Hartwell K.S., Heymann E.W., Hilário R.R., Holmes S.M., Irwin M.T., Johnson S.E., Kappeler P.M., Kelley E.A., King T., Knogge C., Koch F., Kowalewski M.M., Lange L.R., Lauterbur M.E., Louis Jr. E.E., Lutz M.C., Martínez J., Melin A.D., de Melo F.R., Mihaminekena T.H., Mogilewsky M.S., Moreira L.S., Moura L.A., Muhle C.B., Nagy-Reis M.B., Norconk M.A., Notman H., O’Mara M.T., Ostner J., Patel E.R., Pavelka M.S.M., Pinacho-Guendulain B., Porter L.M., Pozo-Montuy G., Raboy B.E., Rahalinarivo V., Raharinoro N.A., Rakotomalala Z., Ramos-Fernández G., Rasamisoa D.C., Ratsimbazafy J., Ravaloharimanitra M., Razafindramanana J., Razanaparany T.P., Righini N., Robson N.M., da Rosa Gonçalves J., Sanamo J., Santacruz N., Sato H., Sauther M.L., Scarry C.J., Serio-Silva J.C., Shanee S., de Souza Lins P.G.A., Smith A.C., Smith Aguilar S.E., Souza-Alves J.P., Stavis V.K., Steffens K.J.E., Stone A.I., Strier K.B., Suarez S.A., Talebi M., Tecot S.R., Tujague M.P., Valenta K., Van Belle S., Vasey N., Wallace R.B., Welch G., Wright P.C., Donati G., Santini L. - PNAS (2022) https://doi.org/10.1073/pnas.2121105119

Further Information

Luca Santinia
Department of Biology and Biotechnologies 'Charles Darwin' 
luca.santini@uniroma1.it