Crespo-Perez V. auteur aut IRD Andino P. auteur aut IRD Espinosa R. auteur aut IRD Dangles Olivier auteur aut IRD Jacobsen D. auteur aut IRD text journalArticle eng text/pdf born digital access We explored mechanisms determining the upper altitudinal limit of ephemeropterans from two different genera: Leptohyphes Eaton, 1882 (Leptohyphidae) and Lachlania Hagen, 1868 (Oligoneuriidae). For this, we (1) surveyed the two taxa in 165 stream sites along a wide altitudinal gradient; (2) sampled benthic fauna at short altitudinal intervals along a stream, from 2780 to 3150 m above sea level; (3) collected adults at the lowest and highest sites; and (4) transplanted nymphs from the lowest to the highest study site in our stream to determine survival over time. Densities of the two taxa declined gradually with altitude and both disappeared between 2950 and 3080 m a.s.l. The upper altitudinal limit in the stream seemed to be most closely related to mean oxygen saturation, temperature, and current velocity. Adults were collected where the nymphs were found, but not at the upstream site where the nymphs were absent, implying limited upstream dispersal of adults and some of the altitudinal constraint lying at the adult stage. Short-term survival of transplanted nymphs was lower than that of controls, suggesting that the distribution was limited at the juvenile stage, and that at least some of the altitudinal constraint is related to the abiotic stream environment. specialized Ephemeroptera Leptohyphes Lachlania abiotic stressors altitudinal limit dispersal stream insects transfer experiment Ecuadorian Andes EQUATEUR ANDES 036 37 1 69-86 2016 0165-0424 https://www.documentation.ird.fr/hor/fdi:010066713 10.1080/01650424.2015.1109128 0165-0424 [F B010066713] https://www.documentation.ird.fr/hor/fdi:010066713 https://www.documentation.ird.fr/intranet/publi/2016/04/010066713.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-05-03 2017-08-23 fdi:010066713 fre