Détail de l'auteur
Auteur Alan Smith |
Documents disponibles écrits par cet auteur (5)
trié(s) par (Pertinence décroissant(e), Titre croissant(e)) Affiner la recherche
Titre : Alpine herbivory on Mount Kenya Type de document : texte imprimé Auteurs : Truman P. Young, Auteur ; Alan Smith, Auteur Importance : pp. 319-335 Langues : Anglais (eng) Résumé : "he savannas of East Africa, perhaps more than anywhere in the world, are known for dramatic plant–animal interactions. Although large herbivores are less common above timberline than below it in East Africa, herbivory is also a powerful force in Afroalpine plant ecology. Many vertebrates and invertebrate herbivore species occur above treeline on Mount Kenya (Moreau 1944; Coe 1967; Jabbal & Harmsen 1968; Coe & Foster 1972; Mulkey et al 1984; Young 1991; Young & Evans 1993). Herbivores influence the distribution of plant species, the size structure of populations, and the success of individual plants on Mount Kenya.
Long-term studies of giant rosette Lobelia and Senecio species have brought to light a number of interesting patterns of herbivory that have major impacts on the biology of these species.
Lobelia
The two high alpine giant rosette lobelias on Mount Kenya are Lobelia telekii and L. keniensis. Mount Kenya lobelias are subject to herbivory from a variety of animal species (Table 18.1). None of the herbivores is host-specific, except perhaps the coleopteran larvae associated with L. telekii roots. Most of these herbivores have only minor effects. However, Lobelia populations near hyrax colonies have suffered severe predation.
The leaves and stems of both Lobelia species are protected by a bitter latex containing anti-herbivore compounds (Mabberley 1975). Although this may limit the activity of their herbivores, it far from renders the plants invulnerable.Type de publication : article de livre Référence biblio : Young T., Smith A., 1994 - Alpine herbivory on Mount Kenya. In : 1994 - Tropical alpine environments : plant form and function. Cambridge University Press, 319-335. ID PMB : 7604 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=7604 Exemplaires(0)
Disponibilité aucun exemplaire
Titre : Introduction to tropical alpine vegetation Type de document : texte imprimé Auteurs : Alan Smith, Auteur Importance : pp. 1-19 Langues : Anglais (eng) Résumé : "The general term ‘tropical alpine’ refers to regions within the tropics occurring between the upper limit of continuous, closed-canopy forest (often around 3500–3900 m) and the upper limit of plant life (often around 4600–4900 m: Hedberg 1951, 1964; Beaman 1962; Troll 1969; Wade & McVean 1969; Wardle 1971; Van der Hammen & Ruiz 1984; Vuilleumier & Monasterio 1986; see Figure 1.1) and is used in preference to regional terms such as ‘páramo’ and ‘jalca’ in the moist Andes from Venezuela to Northern Peru, ‘puna’ in the drier central Andes, and ‘Afroalpine’ and ‘moorland’ in Africa. No clear lower boundary can be defined where natural timberline has been eliminated by man, as in many areas of the Andes and Papua New Guinea (Wade & McVean 1969; Hope 1976; Ellenberg 1979; Ruthsatz 1983), or where the forest is patchy or absent due to low rainfall, as on the north slope of Mount Kenya (Coe 1967; Figure 1.2) and the western slopes of the Peruvian Andes (Weberbauer 1911). In these cases alpine species merge gradually with species of montane pasture, savanna or desert.
Physiognomy of tropical alpine vegetation varies greatly with climatic and edaphic factors; however, certain trends are held in common by many New and Old World tropical alpine areas (see, for example, Hedberg 1964; Coe 1967; Cuatrecasas 1968; Wade & McVean 1969; J. Smith 1977, 1980; Cleef 1978), suggesting convergent evolution (Hedberg & Hedberg 1979; Halloy 1983; Smith & Young 1987)." (source : auteur)Type de publication : article de livre Référence biblio : Smith A., 1994 - Introduction to tropical alpine vegetation. In : 1994 - Tropical alpine environments : plant form and function. Cambridge University Press, 1-19. ID PMB : 7620 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=7620 Exemplaires(0)
Disponibilité aucun exemplaire Population biology of Senecio keniodendron (Asteraceae) - an afroalpine giant rosette plant / Alan Smith
Titre : Population biology of Senecio keniodendron (Asteraceae) - an afroalpine giant rosette plant Type de document : texte imprimé Auteurs : Alan Smith, Auteur ; Truman P. Young, Auteur Importance : pp. 273-293 Langues : Anglais (eng) Catégories : [Espèces (in biblio)] Senecio Résumé : "Senecio keniodendron (Asteraceae) is an abundant and widespread giant rosette species endemic to the alpine zone of Mount Kenya (lat 0°), Kenya. Along with Senecio brassica, it forms a dominant component of the alpine plant community, and shows a high degree of morphological convergence with giant rosette genera in other tropical alpine areas (Hedberg & Hedberg 1979; Smith & Young 1987; Smith, Chapter 1). Here we summarize studies of S. keniodendron population biology carried out between 1977 and 1985, and briefly compare these results with those both for S. brassica, and for the convergent Andean genus Espeletia (Asteraceae).
Senecio keniodendron occurs most commonly on upper slopes and ridges from c. 3700–4600 m elevation. Adult densities generally range from 1 to 10 plants per 100 m2, with greatest densities on talus slopes between 4000 and 4200 m. The mean height of S.keniodendron plants is significantly positively correlated with slope angle (Figure 15.1; r = +0.60; p < 0.001). Senecio keniodendron is replaced by S. brassica on lower slopes and valley floors; S. brassica has a lower elevational range than S. keniodendron – c. 3400–4400 m. The upper limit of growth for S. keniodendron (4600 m) may be due to a combination of drought and freezing stress (see also Perez 1987, on Andean Espeletia). Figure 15.2 shows the surface response curves for the densities of S. keniodendron (p < 0.04) and S. brassica (p < 0.01) im the Teleki Valley, relative to elevation and slope." (source : auteurs)Type de publication : article de livre Référence biblio : Smith A., Young T., 1994 - Population biology of Senecio keniodendron (Asteraceae) - an afroalpine giant rosette plant. In : 1994 - Tropical alpine environments : plant form and function. Cambridge University Press, 273-293. ID PMB : 7606 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=7606 Exemplaires(0)
Disponibilité aucun exemplaire
Titre : Tropical alpine ecology : progress and priorities Type de document : texte imprimé Auteurs : F.C. Meinzer, Auteur ; Alan Smith, Auteur Importance : pp. 355-363 Langues : Anglais (eng) Catégories : [Thèmes] Ecologie Résumé : "As physiological plant ecologists and population biologists continue to work in tropical alpine environments, our knowledge of the form and functional relationships will surely grow rapidly. These ecosystems present unusual challenges for plant establishment and survival, but remain poorly studied. In this closing chapter, we briefly review what we feel are the important accomplishments to date in tropical alpine ecology and the challenges that remain. We focus on plant growth forms, plant demography, physiological convergence, ecosystem function and global climate change.
Plant growth forms
The most striking aspect of tropical alpine habitats is the diversity of plant growth forms, and the apparent convergence between geographically disjunct tropical mountains with respect to these forms (Hedberg & Hedberg 1979; Rauh 1978). Much progress has been made in understanding the ecological and physiological significance of the giant rosette form, perhaps the most conspicuous and typical form of high tropical mountains. However, the majority of tropical alpine growth forms have not been subject to quantitative and experimental analysis. Sclerophyllous-leaved shrubs, cushion plants, tussock grasses and acaulescent rosette forms have received minimal attention. Species in each of these forms may respond differently to changing environmental conditions, and may contribute in very different ways to edaphic, microclimatic and biotic environments.
Classical ecological paradigms suggest the evolution will lead toward convergence in adaptive traits of morphology, phenology, and physiology which provide the ‘best’ ecological solution to similar environmental stresses in disjunct habitats." (source : auteurs)Type de publication : article de livre Référence biblio : Meinzer F.-C., Smith A., 1994 - Tropical alpine ecology : progress and priorities. In : 1994 - Tropical alpine environments : plant form and function. Cambridge University Press, 355-363. ID PMB : 7601 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=7601 Exemplaires(0)
Disponibilité aucun exemplaire
Titre : Tropical alpine environments : plant form and function Type de document : texte imprimé Auteurs : Philip Rundel, Directeur de publication ; Alan Smith, Directeur de publication ; F.C. Meinzer, Directeur de publication Editeur : Cambridge University Press Année de publication : 1994 Importance : 376 p. ISBN/ISSN/EAN : 978-0-511-55147-5 Langues : Anglais (eng) Type de publication : livre Référence biblio : Rundel P. & Smith A.-P. & Meinzer F.-C. (coord.), 1994 - Tropical alpine environments : plant form and function. Cambridge University Press, 376 p. ID PMB : 1345 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=1345 Exemplaires(1)
Cote Localisation Disponibilité R29000110 Brest Exclu du prêt
