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Your search keyword '"Pennington, Terence D."' showing total 16 results
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12. A historical baseline study of the páramo of Antisana in the Ecuadorian Andes including the impacts of burning, grazing and trampling

Author

UCL - SST/ELI/ELIC - Earth & Climate, Grubb, Peter J., Lloyd, J. Robert, Pennington, Terence D., Páez Bimos, Carlos, UCL - SST/ELI/ELIC - Earth & Climate, Grubb, Peter J., Lloyd, J. Robert, Pennington, Terence D., and Páez Bimos, Carlos

Abstract

Background: We report the vegetation at 4050–4600 m in 1960 on the western slopes of Antisana, Ecuador, decades before burning and grazing were prohibited. Aim: To provide a baseline against which new surveys could be compared to evaluate conservation efforts. Methods: We (a) ordinated grassland types and derived communities using constancy values of species in typical stands, (b) recorded evidence of community dynamics, (c) recorded the composition of communities occupying smaller areas than the grassy páramo, and (d) recorded inhibition and facilitation of other species by Azorella cushions. Results: Short-turf grassland had replaced much tall-tussock grassland as a result of grazing and burning. Intense trampling had resulted in dominance by an introduced annual grass. Disturbance of most tall-tussock grassland on lava flows had left gaps made by fire or rabbitscratching; these were invaded by distinctive sets of species. Azonal communities, changed much less by humans, contained 63% of 155 native species of vascular plant encountered, and 68% of 65 mosses. Younger cushions of Azorella impacted negatively on associated species but older cushions had facilitative effects. Conclusions: Our study provides an adequate record against which to determine the extent and nature of changes in the vegetation since farming of livestock ceased.

Published
2020

13. Molecular phylogenetics of Meliaceae (Sapindales) based on nuclear and plastid DNA sequences

Author

Muellner, Alexandra N., Samuel, Rosabelle, Johnson, Sheila A., Cheek, Martin, Pennington, Terence D., and Chase, Mark W.

Subjects
Biological sciences
Abstract

Phylogenetic analyses of Meliaceae, including representatives of all four currently recognized subfamilies and all but two tribes (32 genera and 35 species, respectively), were carried out using DNA sequence data from three regions: plastid genes rbcL, matK (partial), and nuclear 26S rDNA (partial). Individual and combined phylogenetic analyses were performed for the rbcL, matK, and 26S rDNA data sets. Although the percentage of informative characters is highest in the segment of matK sequenced, rbcL provides the greatest number of informative characters of the three regions, resulting in the best resolved trees. Results of parsimony analyses support the recognition of only two subfamilies (Melioideae and Swietenioideae), which are sister groups. Melieae are the only tribe recognized previously that are strongly supported as monophyletic. The members of the two small monogeneric subfamilies, Quivisianthe and Capuronianthus, fall within Melioideae and Swietenioideae, respectively, supporting their taxonomic inclusion in these groups. Furthermore, the data indicate a close relationship between Aglaieae and Guareeae and a possible monophyletic origin of Cedreleae of Swietenioideae. For Trichilieae (Melioideae) and Swietenieae (Swietenioideae) lack of monophyly is indicated. Key words: matK; Meliaceae; nuclear and plastid DNA; phylogeny; rbcL; 26S rDNA; Sapindales.

Published
2003

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