Nestedness is a widely known structuring model in insular and fragmented biotas that has often been assessed, but most studies to date have used a taxonomic approach. However, the relevance of an approach using functional groups has become increasingly highlighted in community ecology research. In this study, we evaluated the occurrence of nested structure in the Jardines de la Reina National Park bird assemblages as a whole, and its trophic guilds by following three different grouping criteria. We constructed species presence–absence matrices for each guild and estimated the degree of nestedness with the metric based on the overlap and decreasing fill, assessing its significance by means of two null models. Overall bird assemblage was significantly nested (NODF = 76.99; p = 0.01) whereas terrestrial insectivores (NODF = 81.32) and insectivores (NODF = 80.04) were the only trophic guilds (out of 19) that showed significant nestedness (p ≤ 0.01). These results could provide evidence of the structural and functional cohesion of avifauna at the study site, especially among its insect–eating taxa. Taxonomic nestedness based on a guilds approach may help identify suitable conservation strategies for avian communities inhabiting naturally fragmented areas such as the Jardines de la Reina National Park.
T he Cuban Giant Trope, Tropidophis melanurus (Schlegel 1837), is the largest species in the genus and also the most abundant in Cuba (Domínguez and Moreno 2003). It has a wide distribution throughout the island and several associated archipelagos (Rodríguez Schettino et al. 2013). The diet of this species consists of frogs (Osteopilus septentrionalis, Eleutherodactylus spp.), lizards (Anolis spp., Leiocephalus spp.), birds, and small mammals (Schwartz and Henderson 1991). However, no report to date documents any Tropidophis attempting to prey on a "crown-giant" ecomorph.The Cuban Giant Anole, Anolis equestris Merrem 1820, is the largest species in this "crown-giant" genus and is widely distributed throughout the Cuban Archipelago (Garrido et al. 2001). Although reports indicate that snakes and mammals take it as prey, the only confirmed predators of A. equestris are birds (Coccyzus merlini, Falco sparverius, and Turdus plumbeus) (Henderson and Powell 2009)."Failed predation" (sensu Begon et al. 2006) occurs when one animal captures another without ingesting it and therefore without receiving an energetic reward. In the case of snakes, which consume their prey whole, the size of the snake relative to its prey can result in a failed predation attempt (e.g., Vincent et al. 2006). Such events have been reported three times in Cuba. Two of those occasions involved T. melanurus (Fong G. et al. 2013;Torres López et al. 2014) and the third was by Cubophis catherigerus (Rodríguez-Cabrera et al. 2016). Herein we report a failed predation attempt by T. melanurus on A. equestris. This constitutes the second case of a Cuban snake trying to feed on a giant anole (see Rodríguez-Cabrera et al. 2016) and the first instance in which the unsuccessful predator was a tropidophiid.At 1120 h on 19 July 2022, we documented attempted predation by an adult male T. melanurus (825 mm SVL) on an adult male A. equestris (approximately 280 mm SVL) when the two animals fell from an Octopus Tree (Shefflera actinophylla, Araliaceae) in the "Humedal Grande" Local Development Project, Morón, Ciego de Avila Province, Cuba (22.122778 N, 78.63111 W). The snake was coiled around the lizard's body and was biting its head while the lizard was biting the snake behind its head (Fig. 1). They held this position for five minutes before an area worker separated them and the lizard ran back to the tree from which they had fallen. Although the snake bore the marks of the lizard's bite, it moved fluidly when released.
La ecología de los ofidios no ha sido casi estudiada en la región de las Antillas. Además, se conoce muy poco sobre los patrones de actividad diaria de las especies que habitan dicha área, así como la forma en que factores ambientales, como la temperatura, las precipitaciones y la disponibilidad de alimento, afectan su actividad. El Jardín Botánico de Cienfuegos posee una abundante población de Tropidophis melanurus (Schlegel, 1837). Para este estudio, se realizaron recorridos al azar de 1 km de largo por cuatro metros de ancho. Los muestreos se efectuaron con una frecuencia mensual durante un año y se tomaron varios datos de los individuos observados, como la actividad o inactividad de estos, la longitud total y el sexo. Los datos de actividad diaria fueron agrupados en bloques de 2 meses para facilitar su análisis. Para comparar la abundancia de los individuos entre las épocas de seca y lluvia se utilizó la prueba chi cuadrado (X2). Los mayores números de individuos activos se registraron en las primeras horas de la noche. Los meses de mayor actividad fueron agosto y septiembre mientras que en los meses de abril y mayo se registraron la menor cantidad de individuos. La actividad de la especie en los períodos de lluvia y seca fue muy semejante, y factores como la temperatura parecen no tener especial relevancia en dicho comportamiento. No obstante, las precipitaciones parecen tener una mayor influencia en la actividad en la especie.
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