Read J., McCoy S., Jaffré Tanguy. (2015). Shade-tolerance of seedlings of rain-forest trees : monodominants vs. subordinates and episodic vs. continuous regenerators. Journal of Tropical Ecology, 31 (6), p. 541-552. ISSN 0266-4674.
Titre du document
Shade-tolerance of seedlings of rain-forest trees : monodominants vs. subordinates and episodic vs. continuous regenerators
Journal of Tropical Ecology, 2015,
31 (6), p. 541-552 ISSN 0266-4674
Several monodominant rain-forest trees in New Caledonia have population size structures suggesting establishment following large-scale disturbance, with eventual replacement by shade-tolerant species predicted in the absence of future disturbance. Links of dominance and population dynamics to leaf-level photosynthesis were investigated in seedlings of 20 tree species from these forests, grown in experimental sun and shade conditions. In particular, we tested whether episodically regenerating (ER) species, including monodominants, have higher assimilation rates at high irradiances and lower tolerance of shade than continuously regenerating species (CR). ER species had higher maximum net assimilation rates (A(max-area)) in sun plants (9.6 +/- 0.4 mu mol m(-2) s(-1)) than CR species (6.2 +/- 0.3 mu mol m(-2) s(-1)) and high plasticity, typical of shade-intolerant species, but monodominant species did not differ from other ER species. CR species had leaf-level traits consistent with shade tolerance, including lower dark respiration rates (Rd-area = 0.47 +/- 0.03 mu mol m(-2) s(-1); Rd-mass = 7 +/- 1 nmol g(-1) s(-1)) than ER species (Rd-area = 0.63 +/- 0.06 mu mol m(-2) s(-1); Rd-mass = 11 +/- 2 nmol g(-1) s(-1)) in shade plants. Hence leaf-level assimilation traits were largely consistent with regeneration patterns, but do not explain why some shade-intolerant species can achieve monodominance.
Plan de classement
Sciences du monde végétal [076]
;
Etudes, transformation, conservation du milieu naturel [082]
