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Dataset for Ongole at al. - Functional traits predict tree-level phenological strategies in a mesic Indian savanna

Citation

Ongole, Shasank et al. (2021), Dataset for Ongole at al. - Functional traits predict tree-level phenological strategies in a mesic Indian savanna, Dryad, Dataset, https://doi.org/10.5061/dryad.hmgqnk9g0

Abstract

Leaf phenology influences terrestrial primary production by determining the period of carbon uptake. While dominant leaf habit (evergreen/deciduous) is predictable at large scales based on environmental factors, there is substantial variability in the timing of key events such as leaf flush and senescence at smaller site-level scales. How much of this variability is explained by species functional traits related to a plant’s carbon economy? We monitored leaf phenology for 113 individual trees of eleven dominant species in an Indian mesic savanna. Specifically, we related leaf functional traits and wood density to the (i) timing of leaf flush, leaf maturity, peak canopy and senescence, (ii) duration of leaf deployment, (iii) duration from start of senescence to leaflessness, and (iv) time to attainment of peak mature canopy following leaf flush. We expected species that use resources conservatively (low specific leaf area (SLA), high leaf dry matter content, low leaf nitrogen and high wood density) to senesce later and retain their leaves longer. For all species, leaflessness was most pronounced in early dry season and leaf flushing occurred in the late dry season. Species with high leaf carbon and dry matter content showed earlier leaf maturation, attained peak mature canopies sooner and deployed leaves longer. Species with high SLA, leaf nitrogen and low wood density showed earlier senescence but relationships were weak. In this savanna, phenology at fine scales was indeed associated with species functional traits relating to carbon investment, but these relationships were strong only when intra-specific variation in phenology was low.

Methods

This dataset is derived from raw data. The raw data are available from the corresponding author upon reasonable request as they are currently under use.

Raw data:

To document phenological patterns of trees, we chose 113 individual trees belonging to eleven dominant species that accounted for 80% of the basal area in our plot (Table S1). The mean number of individuals observed per species ranged between 10 and 12. Only apparently healthy and reproductive individuals with girth at breast height > 20 cm were monitored. Individuals were typically monitored twice a month (1st and 3rd week) for 17 months (September 2017–January 2019), and visually scored for the following variables: canopy fullness (L), and the percentage of flushing (FL), mature (M) and senescing leaves (S). During each session, we assigned a visual percentage score of 0-100 for each phenophase (flushing, mature and senescence) with a resolution of 10%. While the score for canopy fullness was a stand-alone measurement, scores for flushing, mature and senescing leaves add up to 100 as these are proportions of the total canopy score. To the extent possible, the same observer conducted the measurements across the study duration.

The functional trait data is from Ratnam et al. (2019) - Functional Traits of Trees From Dry Deciduous “Forests” of Southern India Suggest Seasonal Drought and Fire Are Important Drivers

 

Funding

Science and Engineering Research Board, Award: EMR/2016/003722

Department of Atomic Energy, Government of India, Award: Project identification number RTI 4006

National Centre for Biological Sciences