Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

© 2016 Ecological Society of Australia. Leaf phenology dictates the time available for carbon assimilation, transpiration and nutrient uptake in plants. Understanding the environmental cues that control phenology is therefore vital for predicting climate-related changes to plant and ecosystem function. In contrast to temperate systems, and to a lesser degree, tropical forest systems, the cues initiating leaf drop in tropical savannas are poorly studied. We investigated the cues for leaf fall in a tropical monodominant arid savanna species, Colophospermum mopane, using an irrigation experiment. We tracked soil moisture, solar radiation, air temperature, leaf water status, leaf h ealth and leaf carbon balance through the dry season in both irrigated and control plants. Water was the primary cue driving leaf loss of C.mopane rather than temperature or light. Trees watered throughout the dry season retained their canopies. These leaves remained functional and continued photosynthesis throughout the dry season. Leaf carbon acquisition rates did not decline with leaf age but were affected by soil moisture availability and temperature. Leaf loss did not occur when leaf carbon gain was zero, or when a particular leaf carbon threshold was reached. Colophospermum mopane is facultatively deciduous as water availability determines leaf drop in this widespread arid savanna species. Obligate deciduosity is not the only successful strategy in climates with a long dry season.

Original publication

DOI

10.1111/aec.12302

Type

Journal article

Journal

Austral Ecology

Publication Date

01/02/2016

Volume

41

Pages

87 - 96