Night and day: Shrinking and swelling of stems of diverse mangrove species growing along environmental gradients

• Published in: PloS one Vol. 14; no. 9; p. e0221950
• Main Authors: Vilas, Maria P., Adams, Matthew P., Ball, Marilyn C., Meynecke, Jan-Olaf, Santini, Nadia S., Swales, Andrew, Lovelock, Catherine E.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.09.2019; Public Library of Science (PLoS)
• Subjects: Air temperature; Australia; Avicennia - growth & development; Avicennia - physiology; Biology and Life Sciences; Carbon; Chemical engineering; Circadian Rhythm; Climate; Climate change; Climatic extremes; Coasts; Drought; Earth Sciences; Ecology and Environmental Sciences; Environmental aspects; Environmental conditions; Environmental gradient; Forests; Mangrove swamps; Mangroves; Maxima; Musical groups; New Caledonia; Night; Physical Sciences; Physiological aspects; Plant Stems - growth & development; Plant Stems - physiology; Plant Transpiration; Rain; Rainfall; Rhizophoraceae - growth & development; Rhizophoraceae - physiology; Salinity; Soil salinity; Soil temperature; Species; Stems; Swelling; Temperature; Tidal flooding; Transpiration; Trees; Trees - growth & development; Trees - physiology; Water; Water - metabolism; Wetlands; Australia; New Caledonia; New Zealand; Norway; St Lucia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0221950

Tree stems swell and shrink daily, which is thought to reflect changes in the volume of water within stem tissues. We observed these daily patterns using automatic dendrometer bands in a diverse group of mangrove species over five mangrove forests across Australia and New Caledonia. We found that mangrove stems swelled during the day and shrank at night. Maximum swelling was highly correlated with daily maxima in air temperature. Variation in soil salinity and levels of tidal inundation did not influence the timing of stem swelling over all species. Medium-term increases in stem circumference were highly sensitive to rainfall. We defoliated trees to assess the role of foliar transpiration in stem swelling and shrinking. Defoliated trees showed maintenance of the pattern of daytime swelling, indicating that processes other than canopy transpiration influence the temporary stem diameter increments, which could include thermal swelling of stems. More research is required to understand the processes contributing to stem shrinking and swelling. Automatic Dendrometer Bands could provide a useful tool for monitoring the response of mangroves to extreme climatic events as they provide high-frequency, long-term, and large-scale information on tree water status.