Abstract Detail

Floristics & Taxonomy

Neill, David A. [1], Asanza, Mercedes [2], Quizhpe, Wilson [1].

Forests and shrublands of the Cordillera del Cóndor, Ecuador: Guiana Shield disjunctions, Andean tepui endemics, and OCBIL theory.

Recent publications in phytogeography have featured discussions of the “OCBIL theory” the “Old, Climatically Buffered Infertile Landscapes” that include regions such as the Cape of southern Africa and southwest Australia and, in the Neotropics, the ancient sandstone tepuis of the Guiana Shield and the “campos rupestres” of the Brazilian shield. The Cordillera del Cóndor in southeastern Ecuador includes the northern portion of the “Andean tepuis”, the sedimentary formations, mainly quartz sandstone, of the sub-Andean cordilleras, east of the main Eastern Cordillera of the Andes in Ecuador and Peru. These discontinuous mountain ranges share lithologic and edaphic characteristics with the Guiana Shield, but the Andean tepuis are at least 20 times younger in age than the Guiana tepuis: these landscapes have been uplifted and exposed with the Andean orogeny and have been available for colonization for plants only since the late Miocene, ca. 10 Ma. The Andean tepuis, therefore, share certain ecological and evolutionary characteristics with the OCBIL landscapes, except for their relative youth. The flora of the Andean tepuis includes at least 12 plant genera disjunct from the Guiana tepuis that presumably arrived via long-distance dispersal since the late Miocene, including wind-dispersed as well as bird-dispersed taxa. Several of these Guiana disjuncts, including Bonnetia (Bonnetiaceae), Crepinella (Araliaceae), and Digomphia (Bignoniaceae) are often among the most abundant tree species at local scales in forest inventory plots in the Cordillera del Cóndor. Tree taxa that derived from genera of the infertile white-sand areas of lowland Amazonia, including Humiria (Humiriaceae) and Pagamea (Rubiaceae) are also locally abundant. The woody flora of the Andean tepuis also includes the endemic and near-endemic genera Stilpnophyllum (Rubiaceae), Godoya and Krukoviella (Ochnaceae), and Cepahlopanax (Araliaceae), a newly described genus (in press April 2021). Above 2000 m elevation and up to 2400 m, the vegetation of the Andean tepuis features dense, low shrublands with numerous endemic species in genera such as Schradera, Ladenbergia, and Palicourea (Rubiaceae), Symplocos (Symplocaceae), Symbolanthus (Gentianaceae).and the tree fern Cyathea. The Andean tepuis, including the Cordillera del Cóndor, may be characterized as YCBILs (young, climatically buffered infertile landscapes), in comparison and contrast with OCBILs, a topic that merits further discussion.

1 - Universidad Estatal Amazonica, El Pangui campus, El Pangui, Zamora-Chinchipe, 190650, Ecuador
2 - Universidad Estatal Amazónica, El Pangui campus, El Pangui, Zamora-Chinchipe, 190650, Ecuador

Keywords:
OCBIL theory
Cordillera del Cóndor
endemism
Floristics.

Presentation Type: Oral Paper
Session: FTI, Floristics & Taxonomy I
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 11:15 AM(EDT)
Number: FTI006
Abstract ID:157
Candidate for Awards:None