Photoperiod controls vegetation phenology across Africa

Adole, Tracy; Dash, Jadunandan; Rodríguez-Galiano, Víctor; Atkinson, Peter M.

doi:10.1038/s42003-019-0636-7

Cited by 49 publications

(41 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Finally, our results seem to contrast earlier research which has shown that phenology of cropland and grassland in sub-Saharan Africa is mainly driven by photoperiodicity, while in our model a longer rainy season will cause a longer growing season (Adole et al, 2019). Photoperiodicity is only implemented for crop PFTs in LPJ-GUESS, while for the natural vegetation PFTs that were used in this study, simulated phenology is driven by water availability and therefore follows the rainy season.…”

Section: Response Of Woody Versus Herbaceous Covercontrasting

confidence: 91%

Contrasting responses of woody and herbaceous vegetation to altered rainfall characteristics in the Sahel

et al. 2021

View full text Add to dashboard Cite

Abstract. Dryland ecosystems are a major source of land cover, account for about 40% of Earth's terrestrial surface and net primary productivity, and house more than 30 % of the human population. These ecosystems are subject to climate extremes (e.g. large-scale droughts and extreme floods) that are projected to increase in frequency and severity under most future climate scenarios. In this modelling study we assessed the impact of single years of extreme (high or low) rainfall on dryland vegetation in the Sahel. The magnitude and legacy of these impacts were quantified on both the plant functional type and the ecosystem levels. In order to understand the impact of differences in the rainfall distribution over the year, these rainfall anomalies were driven by changing either rainfall intensity, event frequency or rainy-season length. The Lund–Potsdam–Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model was parameterized to represent dryland plant functional types (PFTs) and was validated against flux tower measurements across the Sahel. Different scenarios of extreme rainfall were derived from existing Sahel rainfall products and applied during a single year of the model simulation timeline. Herbaceous vegetation responded immediately to the different scenarios, while woody vegetation had a weaker and slower response, integrating precipitation changes over a longer timeframe. An increased season length had a larger impact than increased intensity or frequency, while impacts of decreased rainfall scenarios were strong and independent of the season characteristics. Soil control on surface water balance explains these contrasts between the scenarios. None of the applied disturbances caused a permanent vegetation shift in the simulations. Dryland ecosystems are known to play a dominant role in the trend and variability of the global terrestrial CO2 sink. We showed that single extremely dry and wet years can have a strong impact on the productivity of drylands ecosystems, which typically lasts an order of magnitude longer than the duration of the disturbance. Therefore, this study sheds new light on potential drivers and mechanisms behind this variability.

show abstract

Section: Response Of Woody Versus Herbaceous Covercontrasting

confidence: 91%

Contrasting responses of woody and herbaceous vegetation to altered rainfall characteristics in the Sahel

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Knowledge of what controls the present-day seasonality of basin evaporation would provide a point of reference with which to compare climate and ecosystem models. This evaluation would determine whether these models produce the correct seasonality of evaporation for the right reasons (Maeda et al 2017;Adole et al 2019). Additionally, without a robust understanding of controls on the present-day seasonality, it is difficult to analyse whether model projections of shifts in the seasonality of Congo Basin evaporation are trustworthy (Berg and Sheffield 2019).…”

Section: Introductionmentioning

confidence: 99%

Contrasting controls on Congo Basin evaporation at the two rainfall peaks

et al. 2020

View full text Add to dashboard Cite

Evaporation is a crucial driver of Congo Basin climate, but the dynamics controlling the seasonality of basin evaporation are not well understood. This study aims to discover why evaporation on the basin-wide average is lower at the November rainfall peak than the March rainfall peak, despite similar rainfall. Using 16-year mean LandFlux-EVAL data, we find that evaporation is lower in November than March in the rainforest and the eastern savannah. The ERA5-Land reanalysis, which effectively reproduces this pattern, shows that transpiration is the main component responsible for lower evaporation in these regions. Using ERA5-Land, we find the following contrasting controls on transpiration, and therefore evaporation, at the two rainfall peaks: (a) In the northern rainforest, there is lower leaf area index (LAI) in November, driven by lower surface downward shortwave radiation (DSR), and lower vapour pressure deficit (VPD) in November, driven by lower sensible heat flux that results from lower net radiation. The combination of lower LAI and VPD explains lower transpiration, and therefore lower evaporation, in November. (b) In the southern rainforest, and in the north-eastern savannah, there is lower LAI in November, driven by lower surface DSR, and this explains lower transpiration, and therefore lower evaporation, in November. (c) In the south-eastern savannah, there is lower LAI in November, driven by lower volumetric water content (VWC), and this explains lower transpiration, and therefore lower evaporation, in November. Collectively, these contrasting controls at the two rainfall peaks explain why the basin-wide average evaporation is lower in November than March.

show abstract

“…The citizen science study presented here provides information on four widespread, common tropical species, which can potentially serve as references for future changes in phenology. leaf-out may be triggered, instead, by photoperiod or preceding the onset of monsoons across different latitudes (Adole et al, 2019;Elliott et al, 2006;Ryan et al, 2017). In SeasonWatch, however, we were…”

Section: Discussionmentioning

confidence: 72%

Using Citizen Science to build baseline data on tropical tree phenology

Ramaswami

Sidhu

Quader

2020

Preprint

View full text Add to dashboard Cite

Large-scale and long-term understanding of the phenology of widespread tree species is lacking in the tropics, and particularly in the Indian subcontinent. In the absence of baseline information, the impacts of climate on tree phenology, and thus on trophic interactions downstream of tree phenology, are also poorly understood. Citizen scientists can help bridge this gap by contributing simple, technology-based information over large spatial scales and over the long term. In this study, we describe an India-wide citizen science initiative called SeasonWatch, with preliminary insights into contributor behaviour and species phenology. Over a period of 8 years, between 2011 and 2019, cumulative contributor numbers have increased every year, although consistent contribution remains constant and low. The phenological patterns in the 4 most-observed species (Jackfruit Artocarpus heterophyllus Lam., Mango Mangifera indica L., Tamarind Tamarindus indica L., and Indian Laburnum Cassia fistula L.) are described, with discernible seasonal peaks in flowering and fruiting. Seasonal peaks are influenced by tree phenology reported in the south Indian state of Kerala, which has the maximum number of contributors and most number of observations per contributor, comprising 89% of all observations. We look in detail at the flowering phenology of one particular species, Cassia fistula, which appears to show aberrant phenology, reflecting a potential shift away from historical baselines. Latitudinal patterns in the phenology of widespread species such as Mangifera indica are also discernible from 4 seasonal bioblitz events organised during 2018-19, with trees in lower latitudes exhibiting flowering and fruiting phenology earlier than the higher latitudes. We conclude that there are signs of shifts in phenological patterns, as in the case of C. fistula, and extend a call for action to sustain long-term interest and participation by contributors to develop a baseline for common tropical tree species that can be used to understand long-term consequences of climate change on tropical tree phenology.

show abstract

Photoperiod controls vegetation phenology across Africa

Cited by 49 publications

References 63 publications

Contrasting responses of woody and herbaceous vegetation to altered rainfall characteristics in the Sahel

Contrasting responses of woody and herbaceous vegetation to altered rainfall characteristics in the Sahel

Contrasting controls on Congo Basin evaporation at the two rainfall peaks

Using Citizen Science to build baseline data on tropical tree phenology

Contact Info

Product

Resources

About