Global tiger density linked with forest carbon stock, top-down and bottom-up
Data files
May 02, 2025 version files 31.11 KB
-
anosim_and_adonis_code.R
3.78 KB
-
Cliffs_Delta_AGB_code.R
2.48 KB
-
interaction_model_code.R
2.89 KB
-
Permutation_code.R
1.24 KB
-
README.md
19.26 KB
-
Sample.py
747 B
-
Zonal_Statistics_as_Table.py
706 B
Abstract
Tiger (Panthera tigris) survival, as apex predators in forest ecosystems, largely depends on abundant prey in healthy, intact forests. Because large herbivore prey are drivers of plant biomass, we reasoned that tiger distribution and density are probably also closely linked with forest carbon (C) stock, the management of which is critical for mitigating climate change. However, whether tigers exert top-down control of forest C stocks or are passive surrogate C indicators bottom-up is a salient unanswered question in conservation and management, particularly in trophic rewilding. Here, we compiled estimates of global tiger presence and density to test the top-down effects of tigers on forest C stocks and tiger-carbon relationships along a gradient from “empty forests” without tigers to “target state” ecosystems with tigers living at different abundances. Our results showed that tiger presence was associated with higher forest vegetation C stocks, lower C emissions, and higher C inputs globally. Top-down effects via ungulate biomass were stronger in less established forests. Furthermore, forest vegetation or soil C stocks increased with tiger density or reached tiger-carbon peaks in four forest habitat types covering most of the tiger range. Our findings reveal that tigers, represented by their presence and density, are both an indicator and a driver of forest ecosystem C stocks, depending on underlying ecological conditions, and could safeguard forests against future C emissions and improve our understanding of climate-C cycle feedback.
Access this dataset on Dryad DOI: 10.5061/dryad.cjsxksnhj
Description of the data and file structure
Each script starts with loading the required packages, reading in the data, and converting categorical variables to factors, and describes the analysis workflow. The main scripts are noted from 1 to 4.
Data files contain extracted carbon, biodiversity, and environmental values within an area of interest (rows) derived from corresponding raster data in ArcGIS with either the Zonal Statistics as Table tool or Sample tool, with Python code, variable descriptions, and source information provided below.
Data files and variables
File: anosim_and_adonis_input_data.txt
Description: For manuscript section, “Testing for top-down effects of tiger density on forest carbon stocks”. These data are to be used together with file anosim_and_adonis_code.R. Data in all columns except ‘habitat’, ‘Tigers’, and ‘carboncluster’ are mean values within an area of interest (rows) derived from corresponding raster data in ArcGIS with the Zonal Statistics as Table tool (see Zonal_Statistics_as_Table.py), with sources provided in Access Information below.
Variables
- habitat: 104: temperate forest; 105: subtropical/tropical dry forest; 106: subtropical/tropical moist lowland forest; 109: subtropical/tropical moist montane forest
- carboncluster: low/intermediate or high AGBC/BGBC carbon cluster
- agb: aboveground biomass carbon (MgC/ha)
- bgb: belowground biomass carbon (MgC/ha)
- soc: soil organic carbon (MgC/ha, 0-100 cm depth)
- Tigers: tiger density (individuals/100km2)
- MAP: mean annual precipitation (mm)
- MAT: mean annual temperature (degrees C)
- treediv: tree species richness (species/ha)
File: Cliffs Delta AGB input data.txt
Description: For manuscript section, “Comparing tiger-present and tiger-absent forests”. These data are to be used together with file Cliffs Delta AGB code.R. Column ‘AGB’ is mean values within an area of interest (rows) derived from corresponding raster data in ArcGIS with the Sample tool (see Sample.py), with sources provided in Access Information below.
Variables
- Population: A-Restoration: Tigers absent; C-Species: Tigers present
- habitat: 1.1: boreal forest; 1.4: temperate forest; 1.4NEA: temperate forest (Northeast Asia only); 1.5: subtropical/tropical dry forest; 1.6: subtropical/tropical moist lowland forest; 1.7: subtropical/tropical mangrove vegetation above high tide level; 1.8: subtropical/tropical swamp; 1.9: subtropical/tropical moist montane forest; 1.9Sum: subtropical/tropical moist montane forest (Sumatra only)
- AGB: aboveground biomass carbon (MgC/ha)
File: interaction_model_input_data.txt
Description: For manuscript section, “Indirect tiger-carbon relationships via interactions with other wildlife diversity”. These data are to be used together with file interaction_model_code.R. Data in all columns except ‘habitat’, ‘Tigers’, and ‘ungratio’ are mean values within an area of interest (rows) derived from corresponding raster data in ArcGIS with the Zonal Statistics as Table tool (see Zonal_Statistics_as_Table.py), with sources provided in Access Information below. Where the value is NA (one case, ‘Ungratio’) it indicates that the ratio of ungulates per tiger could not be calculated because the number of tigers was zero. This single row of data was excluded from analyses of ‘Ungratio’.
Variables
- habitat: 104: temperate forest; 105: subtropical/tropical dry forest; 106: subtropical/tropical moist lowland forest; 109: subtropical/tropical moist montane forest.
- AGB: aboveground biomass carbon (MgC/ha).
- SOC: soil organic carbon (MgC/ha, 0-100 cm depth).
- Tigers: tiger density (individuals/100km2). Source:
- BIIrich: Biodiversity Intactness Index (species richness).
- BIIabund: Biodiversity Intactness Index (abundance).
- Ungulates: ungulate biomass (kg/km2).
- diversity1ungulates243: ungulate species richness.
- diversity2ungulates243lagomorphs92: combined ungulate and lagomorph species richness.
- diversity3carnivores251: carnivore species richness.
- ungratio: ungulate biomass per tiger per 100km2.
File: Permutation input data.txt
Description: For manuscript section, “Testing for top-down effects of tiger density on forest carbon stocks”. These data are to be used together with file Permutation code.R. Data in all columns except ‘habitat’, ‘Tigers’, and ‘carboncluster’ are mean values within an area of interest (rows) derived from corresponding raster data in ArcGIS with the Zonal Statistics as Table tool (see Zonal_Statistics_as_Table.py), with sources provided in Access Information below.
Variables
- carboncluster: low: low/intermediate AGBC/BGBC forests; high: high AGBC/BGBG forests
- habitat: 104: temperate forest; 105: subtropical/tropical dry forest; 106: subtropical/tropical moist lowland forest
- Tigers: tiger density (individuals/100km2)
- Ungulates: ungulate biomass (kg/km2)
- diversity1ungulates243: ungulate species richness
- diversity2ungulates243lagomorphs92: combined ungulate and lagomorph species richness
- diversity3carnivores251: carnivore species richnessAGB: aboveground biomass carbon (MgC/ha)
Code files
1 - anosim_and_adonis_code.R
Description: Anosim and adonis tests of the input data (anosim_and_adonis_input_data.txt) to analyse drivers of forest carbon stock variation, including forest habitat type, tiger density, and other environmental factors. Code includes rescaling continuous variables by forest habitat type, creating subsets for ‘low’ and ‘high ‘ carbon forests, and permutations for adonis tests. This code can be used to reproduce results presented in the full manuscript (DOI: 10.1111/gcb.70191) under section “Testing for top-down effects of tiger density on forest carbon stocks”.
2 - Cliffs Delta AGB code.R
Description: Cliff’s Delta (δ) of the input data (Cliffs Delta AGB input data.txt) to compare aboveground biomass carbon stocks in the tiger-present and tiger-absent forests for each forest habitat type. Code first filters the data for the forest habitat type of interest, and includes calculating bootstrapped confidence intervals. Code to be run separately for each forest habitat type/region subset by adjusting the subset value to the corresponding habitat type/region of interest. This code can be used to reproduce results presented in the full manuscript (DOI: 10.1111/gcb.70191) under section “Comparing tiger-present and tiger-absent forests”.
3 - interaction_model_code.R
Description: Generalized Additive Model (GAM) with tensor product smooth terms of the input data (interaction_model_input_data.txt) to test nonlinear interaction between tiger density and diversity/abundance metrics as predictors of aboveground biomass carbon stock. Code includes model validation in the form of leave-one-out cross validation, and the calculation and printing of root mean square error (RMSE) values. Code to be run separately for each forest habitat type/region and variable of interest by adjusting the subset value to the corresponding habitat type/region of interest and replacing ‘Ungulates’ in the GAM model to alternative variables (columns in the input data). This code can be used to reproduce results presented in the full manuscript (DOI: 10.1111/gcb.70191) under section “Indirect tiger-carbon relationships via interactions with other wildlife diversity”.
4 - Permutation code.R
Description: Exact permutation test to compare wildlife diversity/abundance between forests with ‘low’ and ‘high’ carbon (respectively ‘low’ and ‘high’ carbon clusters in input data Permutation input data.txt). Code includes rescaling continuous variables by forest habitat type. This code can be used to reproduce results presented in the full manuscript (DOI: 10.1111/gcb.70191) under section “Testing for top-down effects of tiger density on forest carbon stocks”.
File: Sample.py
Description: This code extracts values of all pixels within an area of interest in a raster file and was originally run in ArcGIS 10.3 (‘Sample’ tool) for both tiger-present and tiger-absent forests in all nine forest habitat types and regions. Data obtained from each run, e.g., aboveground biomass carbon values for all pixels within tiger-present temperate forests in Northeast Asia, were composited and arranged to form Cliffs Delta AGB input data.txt which was then run with code Cliffs Delta AGB code.R to compare aboveground biomass carbon stocks in tiger-present vs. tiger-absent forests in each forest habitat type and region.
File: Zonal_Statistics_as_Table.py
Description: This code extracts mean values of all pixels within an area of interest in a raster file and was originally run in ArcGIS 10.3 (‘Zonal Statistics as Table’ tool). Mean values obtained for each area of interest (i.e., ‘zone’), such as a specific forest habitat type or region, or tiger conservation landscape, were arranged to form anosim_and_adonis_input_data.txt, interaction_model_input_data.txt, and Permutation input data.txt as input data to the respective analyses described above.
Access information
Data were derived from the following sources, described in more detail in Tables S1 and S7 of Roberts, N.J. et al. (2025) (https://doi.org/10.1111/gcb.70191):
Bisht, S., Banerjee, S., Qureshi, Q., & Jhala, Y. (2019). Demography of a high-density tiger population and its implications for tiger recovery. Journal of Applied Ecology, 56(7), 1725-1740. doi:10.1111/1365-2664.13410.
Chanchani, P., Bista, A., Warrier, R., Nair, S., Sharma, R., Hasan, D., & Gupta, M. (2014). Status and conservation of tigers and their prey in the Uttar Pradesh Terai. WWF-India, New Delhi.
Darman, Y., & Bardyuk, V. V. (2021). Rationale for establishing buffer zones around Land of the Leopard National Park and Kedrovaya Pad’ Nature Reserve. Biota and Environment of Natural Areas, 2, 95-108. doi:10.37102/2782-1978_2021_1_7.
Dhakal, M., Karki (Thapa), M., Jnawali, S. R., Subedi, N., Pradhan, N. M. B., Malla, S., . . . Yadav, H. (2014). Status of Tigers and Prey in Nepal. Retrieved from Department of National Parks and Wildlife Conservation, Kathmandu, Nepal.
Duangchantrasiri, S., Umponjan, M., Simcharoen, S., Pattanavibool, A., Chaiwattana, S., Maneerat, S., . . . Karanth, K. U. (2016). Dynamics of a low-density tiger population in Southeast Asia in the context of improved law enforcement. Conservation Biology, 30(3), 639-648. doi:10.1111/cobi.12655.
Fick, S. E., & Hijmans, R. J. (2017). WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology, 37(12), 4302-4315. doi:10.1002/joc.5086.
Fund, W. W. (2013). Tiger Conservation Landscape Data and Report. Retrieved from https://www.worldwildlife.org/publications/tiger-conservation-landscape-data-and-report.
Goodrich, J., Wibisono, H., Miquelle, D., Lynam, A. J., Sanderson, E., Chapman, S., . . . Harihar, A. (2022). Panthera tigris. The IUCN Red List of Threatened Species 2022: e.T15955A214862019.
Grantham, H. S., Duncan, A., Evans, T. D., Jones, K. R., Beyer, H. L., Schuster, R., . . . Watson, J. E. M. (2020). Anthropogenic modification of forests means only 40% of remaining forests have high ecosystem integrity. Nature Communications, 11(1), 5978. doi:10.1038/s41467-020-19493-3.
Gray, T., Channa, P., Pin, C., & Prum, S. (2014). The status of jungle cat and sympatric small cats in Cambodia’s Eastern Plains Landscape. Cat News, 8, 19-23.
Greenspoon, L., Krieger, E., Sender, R., Rosenberg, Y., Bar-On, Y. M., Moran, U., . . . Milo, R. (2023). The global biomass of wild mammals. Proceedings of the National Academy of Sciences of the United States of America, 120(10). doi:10.1073/pnas.2204892120.
Greenspoon, L., & Noor, E. (2023). Source code for “The Global Biomass of Wild Mammals” (1.0).
Hötte, M. H. H., Kolodin, I. A., Bereznuk, S. L., Slaght, J. C., Kerley, L. L., Soutyrina, S. V., . . . Miquelle, D. G. (2016). Indicators of success for smart law enforcement in protected areas: A case study for Russian Amur tiger (Panthera tigris altaica) reserves. Integrative Zoology, 11(1), 2-15. doi:10.1111/1749-4877.12168.
Harihar, A., Ghosh-Harihar, M., & MacMillan, D. C. (2018). Losing time for the tiger Panthera tigris: delayed action puts a globally threatened species at risk of local extinction. Oryx, 52(1), 78-88. doi:10.1017/S0030605317001156.
Harihar, A., Pandav, B., Ghosh-Harihar, M., & Goodrich, J. (2020). Demographic and ecological correlates of a recovering tiger (Panthera tigris) population: Lessons learnt from 13-years of monitoring. Biological Conservation, 252. doi:10.1016/j.biocon.2020.108848.
Harris, N. L., Gibbs, D. A., Baccini, A., Birdsey, R. A., de Bruin, S., Farina, M., . . . Tyukavina, A. (2021). Global maps of twenty-first century forest carbon fluxes. Nature Climate Change, 11(3), 234-240. doi:10.1038/s41558-020-00976-6.
Jenks, K. E., Songsasen, N., & Leimgruber, P. (2012). Camera trap records of dholes in Khao Ang Rue Nai Wildlife Sanctuary, Thailand. Canid News, 15(4).
Jhala, Y. V., Gopal, R., & Qureshi, Q. (2010). Status of tigers, co-predators, and prey in India. Retrieved from National Tiger Conservation Authority, Government of India, New Delhi, and Wildlife Institute of India, Dehradun.
Jhala, Y. V., Qureshi, Q., Gopal, R., & Sinha, P. R. (2011). Status of the Tigers, Co-predators, and Prey in India, 2010. Retrieved from National Tiger Conservation Authority, Govt. of India, New Delhi, and Wildlife Institute of India, Dehradun.
Jung, M., Dahal, P. R., Butchart, S. H. M., Donald, P. F., De Lamo, X., Lesiv, M., . . . Visconti, P. (2020). A global map of terrestrial habitat types. Scientific Data, 7(1), 256. doi:10.1038/s41597-020-00599-8.
Karki, J. B., Jnawali, S. R., Shrestha, R., Pandey, M. B., Gurung, G., & Thapa Karki, M. (2009). Tigers and their prey base abundance in Terai Arc landscape, Nepal. Retrieved from Kathmandu: Government of Nepal, Ministry of Forests and Soil Conservation, Department of National Parks and Wildlife Conservation, and Department of Forests.
Liang, J., Gamarra, J. G. P., Picard, N., Zhou, M., Pijanowski, B., Jacobs, D. F., . . . Hui, C. (2022). Co-limitation towards lower latitudes shapes global forest diversity gradients. Nature Ecology & Evolution, 6(10), 1423-1437. doi:10.1038/s41559-022-01831-x.
Lumbierres, M., Dahal, P. J., Soria, C. D., Di Marco, M., Butchart, S. H. M., Donald, P. F., & Rondinini, C. (2022a). Area of Habitat maps for the world’s terrestrial birds and mammals.
Lumbierres, M., Dahal, P. R., Soria, C. D., Di Marco, M., Butchart, S. H. M., Donald, P. F., & Rondinini, C. (2022b). Area of Habitat maps for the world’s terrestrial birds and mammals. Scientific Data, 9(1), 749. doi:10.1038/s41597-022-01838-w.
Luskin, M. S., Albert, W. R., & Tobler, M. W. (2017). Sumatran tiger survival threatened by deforestation despite increasing densities in parks. Nature Communications, 8. doi:10.1038/s41467-017-01656-4.
Mandal, D., Basak, K., Mishra, R., Kaul, R., & Mondal, K. (2017). Status of leopard Panthera pardus and striped hyena Hyaena hyaena and their prey in Achanakmar Tiger Reserve, Central India. The Journal of Zoology Studies, 4, 34-41.
Mann, R., Warrier, R., & Chanchani, P. (2013). Status of Tiger, Leopard and Prey in Nandhaur Valley, Baseline estimates from the sub-Himalayan Nandhaur region of Uttarakhand, India. Retrieved from WWF-India.
Potapov, P., Hansen, M. C., Laestadius, L., Turubanova, S., Yaroshenko, A., Thies, C., . . . Esipova, E. (2017). The last frontiers of wilderness: Tracking loss of intact forest landscapes from 2000 to 2013. Science Advances, 3(1). doi:10.1126/sciadv.1600821.
Qi, J., Gu, J., Ning, Y., Miquelle, D. G., Holyoak, M., Wen, D., . . . Jiang, G. (2021). Integrated assessments call for establishing a sustainable meta-population of Amur tigers in northeast Asia. Biological Conservation, 261, 109250. doi:10.1016/j.biocon.2021.109250.
Rayan, D. M., & Linkie, M. (2015). Conserving tigers in Malaysia: A science-driven approach for eliciting conservation policy change. Biological Conservation, 184, 18-26. doi:10.1016/j.biocon.2014.12.024.
Sanchez-Ortiz, K., Gonzalez, R. E., De Palma, A., Newbold, T., Hill, S. L. L., Tylianakis, J. M., . . . Purvis, A. (2019). Land-use and related pressures have reduced biotic integrity more on islands than on mainlands. bioRxiv, 576546. doi:10.1101/576546.
Sanchez-Ortiz, K., Newbold, T., Purvis, A., & De Palma, A. (2019). Global maps of Biodiversity Intactness Index (Sanchez-Ortiz et al., 2019 - bioRxiv ): figshare.
Sanderson, E. W., Miquelle, D. G., Fisher, K., Harihar, A., Clark, C., Moy, J., . . . Wood, K. (2023). Range-wide trends in tiger conservation landscapes, 2001 - 2020. Frontiers in Conservation Science, 4. doi:10.3389/fcosc.2023.1191280.
Sharma, R. K., Jhala, Y., Qureshi, Q., Vattakaven, J., Gopal, R., & Nayak, K. (2010). Evaluating capture–recapture population and density estimation of tigers in a population with known parameters. Animal Conservation, 13(1), 94-103. doi:10.1111/j.1469-1795.2009.00305.x.
Spawn, S. A., & Gibbs, H. K. (2020). Global Aboveground and Belowground Biomass Carbon Density Maps for the Year 2010: ORNL Distributed Active Archive Center.
Spawn, S. A., Sullivan, C. C., Lark, T. J., & Gibbs, H. K. (2020). Harmonized global maps of above and belowground biomass carbon density in the year 2010. Scientific Data, 7(1), 112. doi:10.1038/s41597-020-0444-4.
Thapa, K., & Kelly, M. J. (2017). Density and carrying capacity in the forgotten tigerland: Tigers in the understudied Nepalese Churia. Integrative Zoology, 12(3), 211-227. doi:10.1111/1749-4877.12240.
Vinitpornsawan, S. (2013). Population and Spatial Ecology of Tigers and Leopards Relative to Prey Availability and Human Activity in Thung Yai Naresuan (East) Wildlife Sanctuary, Thailand.
Walker, W., Gorelik, S., Baccini, A., Farina, M., Solvik, K., Cook-Patton, S., . . . Griscom, B. (2022). Global Potential Carbon.
Walker, W. S., Gorelik, S. R., Cook-Patton, S. C., Baccini, A., Farina, M. K., Solvik, K. K., . . . Griscom, B. W. (2022). The global potential for increased storage of carbon on land. Proceedings of the National Academy of Sciences, 119(23), e2111312119. doi:10.1073/pnas.2111312119.
Willcox, D. H. A., Phuong, T. Q., Duc, H. M., & An, N. T. T. (2014). The decline of non-Panthera cat species in Vietnam. Catnews, 8, 51-63.
WWF-Russia. (2016). The Amur tiger census in Russia 2014-2015. Retrieved from Vladivostok, Russia.