Objective:

The variation of the taxonomic diversity and species of harvestmen (Opiliones) was evaluated in three locations at different altitudes on the western slope of the Sierra Nevada de Santa Marta (SNSM): La Secreta (LS) (tropical dry forest: 802 m), San Pedro (SP) (montane rain forest: 1450 m) and Hierba Buena (HB) (cloud forest: 2040 m).

Methodology:

In the wooded area of each station, four plots (200x20 m) were delimited adn in each one five points were marked where the capture of Opiliones was carried out with the techniques of pitfall traps, fallen leaves and manual capture at night with white light.

Results:

A total of 671 individuals were captured distributed in 24 RTU (recognizable taxonomic units) of which the most frequent was Phareicranaus sp. nov. 1 with 229 individuals. The greatest diversity of Opiliones was recorded in HB (14 species) and the highest abundance (N = 302) in LS, showing significant differences in both community attributes among the three localities. The specific dominance was notoriously different at each station and the sampling coverage values show that the techniques were efficient (<98% in all stations). Considering beta diversity, the highest dissimilarity value (0.818) was recorded between LS and HB, finding a strong species turnover (mean equal to 0.603) compared to nesting. Regarding taxonomic diversity, the highest value was reported for SP, showing that in supra-specific taxa the assumption of accumulation of species at intermediate altitudes is fulfilled.

Conclusions:

The differences in the indices Δ + and Λ + demonstrated significant changes in the taxonomic structure of Opiliones at a spatial scale in the western slope of the SNSM. In addition, the rich fauna of the area studied is specific to each sampling location due to the climatic conditions and the specific distribution range of each RTU.

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