Populations of the brown frogs Rana arvalis, R. dalmatina and R. temporaria in 46 ponds in south Zealand during the years 1992-2020
Data files
Feb 27, 2024 version files 248.10 KB
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Fog_Supplementary_material_1.xlsx
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Fog_Supplementary_material_2.pdf
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README.md
Abstract
For 29 consecutive years, the populations of three species of brown frogs, Rana arvalis, R. dalmatina and R. temporaria, were monitored in an open area (military training field) in South Zealand, Denmark. Population sizes were recorded by counting egg clumps. Not all egg clumps could be determined to species with full certainty. Some are designated “Likely R. temporaria”, and some are designated “Undetermined”. To obtain the most likely total number of R. temporaria egg clumps, figures for “Certain R. temporaria” and “Likely R. temporaria” should be added. The tables show the number of egg clumps for each species in each of the waterbodies. Some waterbodies exist every year; others came into existence during the study period, and still others are temporary floodings existing only in a few years. In years when a given waterbody did not exist, the cell in the table is left blank.
The waterbodies are numbered from 1 to 46 and their positions are shown on the map.
The data allow analyses of changes in population size from year to year and shifts in the location of breeding populations. Analyses have been made of the time course of colonisation after a water body came into existence. 15 initially unoccupied suitable ponds were available for colonisation by R. dalmatina after 1992. Permanent colonisation usually happened in the very first year that the waterbody existed. A total of 19 initially unoccupied suitable waterbodies could potentially be colonised by the two other species. Rana arvalis permanently colonised 17 ponds after an average of 10.5 years. Rana temporaria permanently colonised eight ponds after an average of 13.4 years.
README: Brown frog colonisations supplementary material
https://doi.org/10.5061/dryad.1g1jwsv3z
Data on the number of egg clumps of three species of brown frogs in 46 water bodies during the period 1992-2020.
Description of the data and file structure
Numerals indicate the number of egg clumps.
If a cell is empty, it was not relevant to investigate the water body, e.g. if it did not exist yet, or did not exist in that year.
(dry) indicates that the water body was practically dry when investigated. This concerns cases when a water body holds water in most other years and so is believed to harbour an otherwise permanent population, which then has to move to another water body in that particular year.
NI means Not Investigated.
0 means that the water body was investigated, but no eggs of that particular species were found.
X means the species was present and spawned, but the eggs were not counted.
Water body numbers refer to the map of the study area, with all 46 water bodies shown. Names of water bodies are the names used by the author.
”Colonisable from” indicates the year of the first spring when the water body existed after it had been restored, or excavated, or formed during winter floodings. In the R. dalmatina data sheet, water bodies that were already inhabited by this species before the start of the study period have no year indicated under this heading.
Methods
The Excel sheets present data on the number of egg clumps of three species of brown frogs, in 46 water bodies, during the period 1992 to 2020 in a 1.8 km² area in Denmark
The map shows the position of the 46 water bodies in the area Kulsbjerge in south Zealand.