PhenObs - Phenological Observations

Botanical Gardens as a Global Phenological Observation Network
Image: PhenObs

About PhenObs

PhenObs PhenObs Image: PhenObs

PhenObs was established in 2017 and is a global network of botanical gardens studying the phenology of herbaceous plant species.

We undertake coordinated, standardized phenological monitoring and measurements of plant functional traits. Because of their diverse collections of plants, botanical gardens represent ideal locations to carry out research across large numbers of species of diverse habitats.

Why phenology?

Phenology is the timing of biological events like first flowering. Phenological studies are important because phenology is especially sensitive to climate change.

Many plant species respond to increased temperatures by adapting the timing of life history events. For example in the past 100 years spring phenology has advanced by on average 11 days. This has important implications for biodiversity, biotic interactions and ecosystem services.

What we monitor

Every week observers across the globe record leaf out, flowering, fruiting and senescence for over 100 herbaceous plant species.

We also measure plant traits, which tell us something about how plants interact with their environment like plant height. We record temperature and precipitation in all gardens. The data is compiled and analysed in the working group Plant Biodiversity of the FSU Jena.

Our aims

Despite half of the plant species on Earth being herbaceous, we know very little about their phenology, as this research has mostly focused on woody species.

PhenObs aims to improve our knowledge of the phenological responses of herbaceous species to the biotic and abiotic environment which will enable us to predict herbaceous phenology from species provenance, climatic requirements, phylogeny and plant traits.

Phenology and climate (change)

Phenological events like the day of leaf unfolding, senescence change with changing climate. In general, spring events occur earlier whereas autumn is delayed and thus, the canopy duration is prolonged when temperatures increase. However, this is highly species specific.

Bild1 Image: AG PlantBioDiv

Phenology captured

Phenology in the Botanical Garden of Jena, e.g. on ground elder (Aegopodium podagraria L.) and lavender (Lavandula angustifolia Mill.):

Ground elder (Aegopodium podagraria L.)

Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
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Lavender (Lavandula angustifolia Mill.)

Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
Image: AG PlantBioDiv
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PhenObs, first results

Bild2 Image: AG PlantBioDiv

The phenological data of the Botanical gardens in Jena, Halle and Berlin showed that the gardens didn’t differ yet the species differed between the years 2017 and 2018. The different stages of flowering (day of first flower buds, peak flowering or last flowering) are highly correlated with day of year of first flower, but this correlation weakens with progression of the flowering phase. Thus, the effort of monitoring can be reduced.

Phenological observations as students course

Also in teaching at the Friedrich Schiller University Jena, phenological surveys and associated analyses are carried out. In 2019, for example, phenological species profiles and observations on pollinator ecology were recorded for individual species. Part of the results can be found in the following fact sheets:

The PhenObs network
Philosophenweg 16
07743 Jena
+49 3641 9-49263
+49 3641 9-49252
Postal address:
Friedrich-Schiller-University Jena
Insitute for Ecology and Evolution
Professorship Plant Biodiversity
Philosophenweg 16
07743 Jena

twitter: @PhenObs
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