The ecology of tree reproduction in an African medium altitude rain forest

Abstract

The occurrence of flowering and fruiting in tropical trees will be affected by a variety of factors, linked to availability of resources and suitable climatic triggers, that may be affected by increasing global temperatures. Community‐wide flowering and fruiting of 2526 trees in 206 plots were monitored over 24 years in the Budongo Forest Reserve (BFR), Uganda. Factors that were assessed included the size of the tree, access to light, the impacts of liana load, effects of tree growth, and variation between guilds of trees. Most flowering occurs at the end of the long dry season from February to April. Trees that had access to more light flowered and fruited more frequently. Pioneer and non‐pioneer light‐demanding species tended to reproduce more frequently than shade‐bearing species. Trees that grew faster between 1993 and 2011 also fruited more frequently. When examining all factors, growth rate, tree size, and crown position were all important for fruiting, while liana load but not growth rate was important in reducing flowering. Trees in BFR show a large decline in fruiting over 24 years, particularly in non‐pioneer light demanders, shade‐bearers, and species that produce fleshy fruits eaten by primates. The decline in fruit production is of concern and is having impacts on primate diets and potential recruitment of mahogany trees. Whether climate change is responsible is unclear, but flowering of the guilds/dispersal types which show declines is correlated with months with the coolest maximum temperatures and we show temperature has been increasing in BFR since the early 1990s.

Inter‐annual variability of fruit timing and quantity at Nouragues (French Guiana): insights from hierarchical Bayesian analyses

“…, Babweteera et al . ). In the case of our remote study area at Nouragues, French Guiana, 29% of the biweekly censuses were missed due to logistic problems.…”

Rethinking tropical phenology: insights from long‐term monitoring and novel analytical methods

“…The detailed investigations of many factors such as growth rate, canopy position, dispersal type, fruit production, tree size and liana infestation, enlighten the identification of the many variables defining phenology patterns at different scales in tropical forests (Babweteera et al . ).…”

Current issues in tropical phenology: a synthesis

“…The emerging analyses of individual performance through time will greatly improve explanatory models of tree behavior based on direct observations (Babweteera et al . , Ouédraogo et al . ).…”

“…Long-term datasets on individual tree phenology are critical to understanding how the trees' recurrent cycles vary within a population and change through a tree's lifetime. The emerging analyses of individual performance through time will greatly improve explanatory models of tree behavior based on direct observations (Babweteera et al 2018, Ou edraogo et al 2018.…”

“…Sites from which long-term directly observed tropical phenology data have been published (blue dots) and the long-term observation sites included in this special section (red dots). Sources of site locations and minimum available dataset lengths: Adamescu et al 2018, Babweteera et al 2018, Brearley et al 2007, Chen et al 2018, Chang-Yang et al 2016, Dunham et al 2018, Kurten et al 2018, Mendoza et al 2017, Plumptre et al 2012, Sakai 2001. Maidment et al 2017, IPCC 2013.…”