Population status of the tree Sacoglottis holdridgei (Humiriaceae) at Isla del Coco National Park, Costa Rica

Abstract

Isla del Coco is the only oceanic island in the Eastern Pacific with humid tropical climate. Its forests have a particular structure with a unique array of plant species and high endemism. There are few studies on the flora or forest monitoring on the island. The population structure of Sacoglottis holdridgei was analyzed using data from six years with data points taken in 2006 and 2012, including sampling of regeneration in 2012. Sacoglottis holdridgei was the most important tree species, presenting in 2012 the highest Importance Value Index (190.7±21.8), abundance (158.5±40.3 Nha -1 or 39.5 % of the forest) and basal area (15.6 m 2 ha -1 or 72.9 % of the forest). It was present in all three height strata with dominance in the highest. Annual mortality was reported at 3.3 % and recruitment at 1.2 %. The diameter distribution of forest fits the inverted J model, but not for the reported species of which only S. holdridgei tends to adjust for DBH>40 cm. Regeneration fitted the inverted J model with values below those reported for continental forests. Even though it was the dominant species, S. holdridgei showed low regeneration values. This particular condition, give way hypotheses related to the introduction of species, species biology and climate change which could influence the future development of S. holdridgei and forests of Isla del Coco. Rev. Biol. Trop. 64 (Suppl. 1): S263-S275. Epub 2016 Febrary 01.

Comportamiento reproductivo, forrajeo y uso de hábitat de Coccyzus ferrugineus (Cuculiformes: Cuculidae) en la Isla del Coco, Costa Rica

“…hasta los 575 m.s.n.m. (Acosta-Vargas, 2016;Montoya, 2016). Es una isla oceánica formada por procesos volcánicos en la cordillera submarina, situada sobre la placa de Cocos con una edad estimada entre 1.91 y 2.44 millones de años (Bellon, Saenz, & Tournon, 1983).…”

“…Vidal, & Nogales, 2014;Fourriére, Azofeifa-Solano, & Sandoval, 2016). A pesar de que esta amenaza se considera uno de los principales problemas que afectan al ecosistema terrestre de la isla (Dawson et al, 2015;Acosta-Vargas, 2016) el impacto de las especies introducidas ha sido poco analizado para las aves endémicas de la Isla del Coco (Fourriére et al, 2016). Las principales especies que anidan en la Isla del Coco son Anous stolidus, A.…”

Dynamic and growth of the forests of the Isla del Coco National Park, Costa Rica

“…The understory is clear, mostly dominated by bushes and the grass Hypolytrum amplum (Poepp. & Kunth in Kunth, Enum., 1837) (Cyperaceae, Trusty et al, 2006), and regeneration of canopy species are scarce (Acosta-Vargas, 2016). The forest has a low diversity compared with the Costa Rica continental forests.…”

“…Recent studies of Porras-Jiménez (2012) started the documentation of tree mortality in the forest of Isla del Coco, leading to changes in the floristic composition and vegetation structure. This study aroused interest in additional research focused on population status and structural changes in the forests (Acosta-Vargas, 2016). In general, the investigation had been focused on flora descriptions (Rivera, 2006;Trusty et al, 2006;Zamora, 2008).…”

Effectiveness of two treatments to promote tree regeneration: implications for forest restoration in the Isla del Coco National Park, Costa Rica

“…The areas abandoned for more than a century were unable to recover the native forests, and the effects of deforestation and introduced fauna are still visible in the landscape of the PNIC. Moreover, other investigations report harmful effects on soil erosion (Sierra, 2001), and the alteration in regeneration patterns and forest structure, caused by selective herbivory on some tree species (Acosta-Vargas, 2016;Montoya, 2016;Bonilla-Mata & Acosta Vargas, 2020). These impacts are evident, although the effects of deforestation and its synergy with the introduction of flora and fauna in the PNIC have been scarcely studied.…”