Examinando por Materia "Niche"

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    PublicaciónEmbargo
    Patrones de distribución de la riqueza de colibríes del bosque seco tropical en el Caribe colombiano
    (Universidad de Córdoba, 2025-04-29) Arroyo Garcés, Lucas Moises; Linares Arias, Juan Carlos; Carrillo Fajardio, Merly Yenedith; Chacon Pacheco, Julio Javier
    Se describieron los patrones de distribución de la riqueza de colibríes de acuerdo con algunas las condiciones ecológicas del bosque seco tropical en el caribe colombiano, utilizando modelos de distribución ecológica con en variables climáticas, estructurales y bióticas en los que se estimó la contribución de las variables que influyen en la distribución de la riqueza de colibríes en este ecosistema y se analizó como los rasgos funcionales de los colibríes influyen en su distribución a escala regional. Los resultados muestran que la riqueza de colibríes en el BST del Caribe colombiano no sigue un patrón uniforme. Se identifican 11 subregiones con distintos niveles de riqueza, determinados por factores como gradientes ambientales y endemismo. Las áreas con mayor riqueza incluyen PNN Tayrona, el Bajo Magdalena y los Montes de María, mientras que zonas con condiciones más secas o degradadas, presentan menor riqueza como La cuenca media del rio Cesar o La Guajira. Las variables que más contribuyeron a los modelos fueron las bióticas, seguida por la precipitación del trimestre más frio y la altura de dosel. Además, al explorar la relación entre los atributos morfológicos de los colibríes y su distribución, se evidenció que especies con especializaciones morfológicas, como picos largos y curvados, no presentan distribuciones más restringidas, lo que sugiere que una relación entre la especialización y la distribución es más compleja y dependería de la escala.
  • Miniatura
    PublicaciónAcceso abierto
    Utilizando biogeografía histórica y modelos de nicho ecológico para analizar la diversificación del grupo de especies Craugastor Fitzingeri
    (2023-01-27) Bracho Altamiranda, Cesia Nela; Bracho Altamiranda, Faidith; Ortega León, Ángela
    Historical biogeography in essence is the study of the geographic distribution of organisms in terms of their evolutionary history. Studying the relationship between geographic space and species diversity provides an important tool to understand at least in part the speciation process, especially in very diverse and widely distributed groups, such as the species of the genus Craugastor; which, not only present particular characteristics of life history, but also of evolutionary history. This introduces great tension when trying to understand how the northsouth recolonization events occurred above oceanic waters. The group of species Craugastor fitzingeri, which includes eight species distributed from northern Central America to northern South America, is of Central American origin; Therefore, six hypotheses related to the biogeographic history of this species (I,II,III,IV), a phylogeographic analysis (V) and environmental comparisons of the niche of said species (VI) were tested. To analyze the phylogenetic relationships and the divergence times of the species of the group, a phylogeny was carried out under Bayesian inference with estimated divergence times. In order to identify the most important events in the diversification of the east and its relationship with the geological and/or biogeographical history of the continent, a ancestral ranges reconstruction was carried out using the S-DIVA method, and the biogeographical regions established by Morrone (2014). Once these two points were analyzed, different paraphyletic groups were observed eventhough the C. fitzingeri clade was monophyletic (Pp=1); therefore, C. longirostris was taken as a case study to review how much molecular variation could be recorded in a widely distributed species. For this, the calculation of genetic distances (Tamura-Nei), a phylogenetic tree under Bayesian inference for the species and an analysis of genetic structure (Fst) were performed. Finally, the environmental niches of the species of the group were compared, using a niche equ ivalence test and a niche similarity test. Hypotheses I and II were fulfilled, since the dispersion was the most important event to explain the diversification of the group, in addition to having correspondence with the geological events of the continent. The phylogenetic relationships of the group were not very clear, but three independent lineages could be distinguished in the Colombian Chocó for C. longirostris, so it is possible that adaptations are taking place at the local level. The Fst values were close to 1, thus confirming that a case of directional selection may be occurring, at least for the Colombian C. longirostris populations. The comparisons in the environmental space, although they were not conclusive, allow us to infer that ecological 10 studies should not be separated from the genetic processes and the phylogeographic patterns of the species. It is also recommended to include more genetic information that covers a greater range of distribution for each species, added to a greater diversity of genes.