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Surprising roles of climate in regulating flowering phenology in a subtropical ecosystem

Citation

Song, Zhuqiu; Du, Yanjun; Huang, Zhongliang (2021), Surprising roles of climate in regulating flowering phenology in a subtropical ecosystem, Dryad, Dataset, https://doi.org/10.5061/dryad.qfttdz0f0

Abstract

This dataset contains data from the paper: “Song, Z., Du, Y., Primack, R.B., Miller-Rushing, A.J., Ye, W., Huang, Z. (2021) Surprising roles of climate in regulating flowering phenology in a subtropical ecosystem. Ecography. https://doi.org/10.1111/ecog.05629”. 

This phenological data set included a total of 1892 collections, representing 105 native species, belonging to 76 genera of 42 families, and spanning a 105-year period from 1911 to 2015. This dataset contained 1540 herbarium specimens (81%, 1911−2012) and 352 photographs (19%, 20022015). Data for each species covered at least a 49-year time span and included at least 8 years of data, and also went through at least three of four periods in global warming during 1911−2015, i.e. early 20th century warming (1911−1941), mid 20th century hiatus (1942−1973), late 20th century warming (1974−2001), and early 21st century slowdown (2002−2015). All species were grouped into spring-flowering (March to May, 56 species), summer-flowering (June to August, 26 species), autumn-flowering (September to November, 19 species) and winter-flowering (December to February, 4 species), based on the mean flowering month of each species.

Methods

We collected flowering phenology data from 26,048 herbarium specimens, representing 105 native species, collected in the Nanling region. Images of most specimens were available on-line from the National Specimen Information Infrastructure (NSII, http://www.nsii.org.cn/) and Chinese Virtual Herbarium (CVH, http://www.cvh.ac.cn/). We examined specimens in the herbaria if they lacked on-line images. We also analyzed about 3000 photographs of plants, which were available from the Chinese Field Herbarium (CFH, http://www.cfh.ac.cn) and Plant Photo Bank of China (PPBC, http://www.plantphoto.cn). For each specimen and photograph, we recorded the phenological stage and the label information or metadata, including collector, number, date, location, and elevation of collection.

Herbarium specimens and photographs (collectively referred to as “collections”) showing more than 50% of flowers in full bloom were considered as peak flowering at the time of collection and were included in our analysis. For the species with elongated raceme inflorescences, such as Lysimachia fortunei, collections with open flowers in the middle position of the inflorescence were also treated as being in peak flowering. These collections were geo-referenced through online tools (e.g. GPSspg: http://www.gpsspg.com/) with elevation estimated for each collection location based on a combination of georeferenced coordinates and habitat information from specimen labels. All collections without peak flowering dates, precise collection dates, or specific locations, and all duplicate collections of the same species collected on the same dates and places were removed from our data.

Flowering date of each collection was converted to day of year (DOY). For the three winter-flowering species (Litsea cubeba, Michelia maudiae, and Eurya chinensis), flowering dates were converted to days before and days after January first, to create a continuous record over the course of the flowering season. A midpoint of the date range was calculated when there was a cluster of collections of the same species in the same year and place. Our data were also checked for normality and presence of outliers. Outliers that flowered more than two standard deviations from the mean flowering of each species were discarded; this filter excluded specimens that flowered outside of the normal flowering season for a species, such as spring-flowering species that might sometimes weakly flower a second time in the autumn.

Usage Notes

The readme file contains an explanation of each of the variables in the dataset, in which no missing value was included.

Funding

National Natural Science Foundation of China, Award: 31670480

National Natural Science Foundation of China, Award: 31570527

National Specimen Information Infrastructure of China, Award: 2005DKA21400

National Natural Science Foundation of China, Award: 31600165

National Specimen Information Infrastructure of China, Award: 2005DKA21400