DOI: 10.5061/dryad.m0cfxpp7z
title: Data from: Seasonality in the equatorial tropics: Flower, fruit and leaf phenology of montane trees in the highlands of southwest Uganda

description: Phenology influences many forest functions and can inform forest
 conservation and management, yet representative phenological data for most
 common tropical forest tree species remain sparse or absent. Between June
 2011 and December 2013, we investigated flowering, fruiting and leafing
 patterns in the Bwindi Impenetrable National Park, a montane forest
 located near the equator in Uganda, drawing on 16,410 observations of 530
 trees of 54 species located between 2,066 and 2,527 m in elevation. The
 park’s climate is equatorial with two wet and dry seasons each year.
 Flowering and fruiting were strongly seasonal while patterns in leafing
 were less pronounced. Flower occurrence peaked at the beginning of the
 short dry season followed by a pronounced trough during the beginning and
 the middle of the short wet season. Fruit occurrence had a pronounced peak
 during high rainfall months in March through April with most fruits
 ripening during drier months in May through July. Fruit scarcity was
 observed for a 4-month period spanning September to December and most
 flushing of leaves noted at the end of the wet season in November and
 December. Our binomial generalised linear mixed models (GLMM) indicated
 that flowering and fruiting were negatively associated with temperature
 and that leafing activity was positively associated with rainfall and
 temperature. These findings are consistent with the insolation- and
 water-limitation hypotheses suggesting that the seasonally varying
 availability of resources such as light, water and nutrients determines
 these phenological patterns. Ideally, prolonged, multi-year
 community-level studies would be supported so as to better characterise
 the influence of climate and of climate variability.
description: A total of 530 trees were monitored each month for two and a half
 years, starting in June 2011 and ending in December 2013. Our team
 observed each tree at monthly intervals using binoculars and recorded
 comparable estimated counts of flowers, fruits and leaves (see Table S4).
 The presence and quantity per tree of flower buds, open flowers, fallen
 flowers, unripe fruits, ripe fruits, rotten or dry fruits, fallen fruits,
 new leaves, old leaves, damaged leaves, senescent leaves and fallen leaves
 were recorded by assigning a score between zero and four. The score of 0
 represents absence of a phenophase, 1 represents an abundance of 1–10, 2
 represents an abundance of 10–100, 3 represents an abundance of 100–1000
 and 4 represents an abundance greater than 1000 counts of a given
 phenophase. Categories of flowers, fruits and leaves of some species were
 deemed “difficult to distinguish” and subsequently dropped from the data
 collection protocol (see Table S2 for a more complete description). For
 instance, damaged leaves were not scored for <em>Erica
 benguelensis</em>. We replaced trees that died (n = 8) with nearby
 trees of the same species. Categorical abundance measures of each
 phenological variable for each individual tree were converted into
 activity indices, i.e. absence–presence data (absent if zero, present if
 greater than zero), and used to calculate the proportion of each study
 species observed bearing flowers, fruits and leaves in each calendar
 month. The absence–presence data were also used to test for seasonality
 and the role of rainfall and temperature on the occurrence of phenological
 events.
description: The data files can be accessed using Office Word reader and MS
 Office Excel.