Data from: Disentangling the effects of temperature and rainfall on the population dynamics of Kalahari meerkats
Data files
Dec 09, 2024 version files 1.09 MB
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MeekatPopulationAnnualBodyMass.csv
1.74 KB
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MeekatPopulationDensity.csv
41.21 KB
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MeekatPopulationSeasonalBodyMass.csv
5.85 KB
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MeerkatAgeStructure.csv
38.72 KB
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MeerkatDailyTemp.csv
835.09 KB
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MeerkatDemography.csv
5.64 KB
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MeerkatGroupExtinction.csv
19.90 KB
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MeerkatMonthlyRain.csv
18.69 KB
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MeerkatSIVofNDVI.csv
1.65 KB
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MeerkatSPEI.csv
99.83 KB
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MeerkatTrends.csv
14.83 KB
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README.md
9.43 KB
Abstract
In arid habitats, recent increases in summer temperatures associated with global warming are adversely affecting many animal populations. However, annual rainfall also varies widely in many of these areas, and we do not yet fully understand the relative impact of variation in temperature and rainfall on the demography of arid-zone species. Here, we examine the effects of temperature and rainfall variation on the demography of meerkats (Suricata suricatta) in the southern Kalahari over the last 25 years. During this period, average maximum monthly air temperatures at our study site increased by around 1.5ºC to 3.2ºC, while annual rainfall fluctuated without a consistent trend. We show that annual changes in female fecundity and recruitment were more closely correlated with variation in rainfall. Increasing air temperatures were associated with reductions in the recruitment of pups and the survival of some age classes but, in most cases, the demographic consequences of high temperatures were modest compared to the effects of low rainfall, which in some years led to the near cessation of successful reproduction and the extinction of many smaller groups. For instance, exceptionally low rainfall in 2012-2013 was associated with low recruitment and with declines in group size and population density, which fell by over 50%. Unusually hot years did not have similar consequences. Following the 2012-2013 drought, intermittent years of low rainfall and frequent droughts continued to suppress recruitment and slowed the population’s recovery. Future changes in temperature may affect the dynamics and size of the meerkat population, but our work suggests that over the last 25 years, annual changes in rainfall have exerted a stronger influence on meerkat demography. Our study demonstrates the importance of long-term, individual-based data for determining how changes in climate affect the dynamics of animal populations, especially in arid environments where bottom-up processes often dominate.
README: Disentangling the effects of temperature and rainfall on the population dynamics of Kalahari meerkats
https://doi.org/10.5061/dryad.brv15dvj5
The R code and data sets in the repository can be used to replicate the analyses in our paper "Disentangling the effects of temperature and rainfall on the population dynamics of Kalahari meerkats" (https://doi.org/10.1111/oik.10988)
The aim of the study was to explore the relative impact of variation in rainfall and temperature on the demography and population dynamics of meerkats, a cooperatively breeding mongoose that lives in the semi-arid regions of southern Africa.
The analyses are contained within four distinct R scripts.
(1) Analysis 1 - Climate and vegetation productivity trends and relationships.R
(2) Analysis 2 - Trends in demographic parameters and adult body mass.R
(3) Analysis 3 - Effects of climate on demographic parameters.R
(4) Analysis 4 - Group extinctions.R
All data sets are also contained within the repository.
(1) MeerkatMonthlyRain.csv - Long-term rainfall data for the Kalahari
rain_noaa: monthly total rainfall (mm) from the Climate Prediction Center’s global preciptation product (NOAA, 2023)
rain_gpcp: monthly total rainfall (mm) from the Global Precipitation Climatology Project v3.2 (Huffman et al., 2023)
rain_onsite: monthly total rainfall (mm) measured onsite at the Kalahari Research Centre.
(2) MeerkatDailyTemp.csv - Long-term temperature data for the Kalahari
tempmin_noaa: daily minimum near-surface air temperature (°C) from the Climate Prediction Center’s global temperature product (NOAA, 2023)
tempmax_noaa: daily maximum near-surface air temperature (°C) from the Climate Prediction Center’s global temperature product (NOAA, 2023)
tempmid_noaa: daily mean near-surface air temperature (°C) from the Climate Prediction Center’s global temperature product (NOAA, 2023)
(3) MeerkatSPEI.csv - Long-term drought index for the Kalahari
SPEI-1: 1-month Standardized Precipitation-Evapotranspiration Index (SPEI), taken from the global SPEI database (Beguería et al., 2014)
SPEI-2: 2-month Standardized Precipitation-Evapotranspiration Index (SPEI), taken from the global SPEI database (Beguería et al., 2014)
...SPEI-X: Further X-month SPEI values, taken from aken from the global SPEI database (Beguería et al., 2014)
(4) MeerkatSIVofNDVI.csv - Annual vegetation productivity in the Kalahari
- SIV_NDVI_mean: The mean small integral value of NDVI across the meerkat population in each breeding season*. The SIV of NDVI, which provides a measure of total vegetation productivity per season, was calculated with the TIMESAT software v3.3 (Jönsson and Eklundh, 2004) on using NDVI time series data taken from the MODIS MOD13Q1 product (Didan et al., 2015).
- AnnualRainfall_GPCP: Total annual rainfall (mm), as measured by the GPCP project, in each breeding season.
- AnnualRainfall_NOAA: Total annual rainfall (mm), as measured by the CPC product, in each breeding season.
- AnnualRainfall_Onsite: Total annual rainfall (mm), as measured onsite, in each breeding season.
(5) MeerkatPopulationDensity.csv - Monthly population size and density
- nGroups: Number of meerkat groups contributing to the populaiton size and density measures. In this paper, only established groups provided high resolution GPS data were considered. From these groups we could estimate individual or group-level density.
- PopulationSize: The number of meerkats in the population each month. Mean of daily counts.
- MeanGroupSize, l95GroupSize, u95GroupSize: The mean group size in each month, with associated confidence intervals estimated through bootstrapping.
- IndDensity_KDE, l95IndDensity_KDE, u95IndDensity_KDE: The mean population density (individuals/km²) in each month, with associated confidence intervals calculated through jack-knifing. The KDE refers to the fact that density was estimated by aggregating the 95% Kernel density estimate of each group's space use, before dividing the number of individuals over this area.
- GroupDensity_KDE, l95GroupDensity_KDE, u95GroupDensity_KDE: The mean group density (groups/km²) in each month.
(6) MeerkatAgeStructure.csv - The age structure of the population of time
- AgeClass: Either pups (< 90 days), Juveniles (90 days - 6 months), Subadults (6 months - 1 year), Adults (> 1year)
- Proportion: Proportional representation of the age class in the population
(7) MeerkatTrends.csv - Annual demographic rates in the population (per breeding season*)
- ngroups: number of groups followed across the year
- mean_pregnancies: mean number of pregnancies recorded per group (± SD, ± SEM)
- mean_dompregnancies: mean number of dominant female pregnancies recorded per group (± SD, ± SEM)
- mean_subpregnancies: mean number of subordinate female pregnancies recorded per group (± SD, ± SEM)
- mean_subpregnancies_percapita: mean number of subordinate pregnancies recorded per group per capita (± SD, ± SEM)
- mean_litters: mean number of litters born per group (± SD, ± SEM)
- mean_domlitters: mean number of litters born to subordinate females per group (± SD, ± SEM)
- mean_sublitters: mean number of litters born to dominant females per group (± SD, ± SEM)
- mean_fecundity*_*pergroup: mean number of pups born per group (± SD, ± SEM)
- mean_recruitment_pergroup: mean number of pups recruited to 90 days per group (± SD, ± SEM)
- totaladult/subadult/juvenile/pupsurvival: Total survivorship of individuals in each of the four age classes. For adults, subadults, and juveniles, survival was assessed from the start of one breeding season to the next breeding season. For pups, it was estimated for all pups born in the year, between emergence to recruitment at 90 days.
- meanadult/subadult/juvenile/pupsurvival_pergroup: As for the former, but averaged per group (± SD, ± SEM).
(8) MeerkatPopulationAnnualBodyMass.csv - Long-term variation in adult body mass
- nind: Number of adults weighed in the population in the breeding breeding season.
- nwtsperind: Number of times each adult was weighed across the breeding season, on average.
- avgMass: The mean of each individual's mean mass across the year (± SD, ± SEM)
(9) MeerkatPopulationSeasonalBodyMass.csv - Long-term variation in adult body mass across seasons
- As for (8) but separated into three climatically distinct seasons, early summer (Sep-Nov), late summer (Dec-Apr), and winter (May-Aug).
(10) MeerkatDemography.csv
- A streamlined version of dataset (7) that was used in analysis (3). All column headers follow that used in dataset (7).
(11) MeerkatGroupExtinction.csv - Annual survivorship of meerkat groups ~ group size.
- GroupRef: Unique group identifier
- FinalEndDate: On what date did the group end.
- breeding_season: The breeding season
- GroupSize: Group size at the start of the breeding season*.
- Fate: How did the group end (Failed/FollowEnded/Current2023).
- FinalYear: Was is the group's last year in the population (N/Y)
- Failed: Did the group fail and thus go extinct in the given year.
If you would also like further information on other aspects of the paper, including additional code that I used to generate the datasets (e.g. climate data, SIV of NDVI, home range sensitivity analyses), then I can be contacted at jackthorley1@gmail.com.
The code and data sets are also available at: https://github.com/JThor1990/Meerkat-Population-Regulation
Missing data; NA
References:
Beguería, S., Vicente-Serrano, S.M., Reig, F. and Latorre, B. 2014. Standardized precipitation evapotranspiration index (SPEI) revisited: parameter fitting, evapotranspiration models, tools, datasets and drought monitoring. – Int. J. Climatol. 34(10): 3001-3023.
Didan, K., Munoz, A. B., Solano, R. and Huete, A. 2015. MOD13Q1 MODIS/Terra Vegetation Indices 16-Day L3 Global 250m SIN Grid V006. NASA EOSDIS Land Processes DAAC. – https://doi.org/10.5067/MODIS/MOD13Q1.006.
Huffman, G.J., Adler, R.F., Behrangi, A., Bolvin, D.T., Nelkin, E.J., Gu, G. and Ehsani, M, R. 2023. The new version 3.2 Global Precipitation Climatology Project (GPCP) monthly and daily precipitation products. – J. Climate, 32(21): 7635-7655.
Jönsson, P. and Eklundh, L. 2004. TIMESAT- a program for analysing time-series of satellite sensor data. – Comput. Geosci. 30(8), 833-845.
National Oceanic and Atmospheric Administration NOAA. 2023. CPC Global Daily Temperature & Global Daily Precipitation – https://www.psl.noaa.gov/data/gridded/data.cpc.globaltemp.html. https://www.psl.noaa.gov/data/gridded/data.cpc.globalprecip.html.
*Note that breeding seasons cover the period from July 1st to June 30th in the following year. This best reflects rainfall patterns in the Kalahari, where most rain falls in the austral summer, between October and April.
Methods
The data was collected as part of a long-term study of meerkats in the southern Kalahari Desert. All methods of data collection are outlined in the paper and are also summarised in Clutton-Brock and Manser (2016). The project's data is stored on a centralised SQL database and was processed for analyses by the lead author using R.
Clutton-Brock, T.H., & Manser, M.B. (2016) Meerkat: cooperative breeding in the Kalahari. In Cooperative breeding in vertebrates. (eds, W.D. Koenig, & J.L. Dickinson), pp. 294-317. Cambridge University Press, Cambridge, UK. https://doi.org/10.1017/CBO9781107338357.018