CABAH / SavannaCorridors

Analysis of palaeoecological records across South-East Asia to determine the evidence for regime shifts between open savannas and dense tropical forests occurred since the Last Glacial Maximum

Testing evidence for savanna corridors in South-East Asia since the Last Glacial Maximum

Analysis of palaeoecological records across South-East Asia to determine the evidence for regime shifts between open savannas and dense tropical forests occurred since the Last Glacial Maximum

Code contributors: Rebecca Hamilton, Corey J. A. Bradshaw, Frédérik Saltré, Jesse Wolfhagen

Accompanies paper (in review):

Hamilton, R, N Amano, CJA Bradshaw, F Saltré, R Patalano, D Penny, J Stevenson, J Wolfhagen, P Roberts. 2023. Seasonal forests, not long-term savanna corridors, dominated in South-East Asia during the Last Glacial Maximum.

Abstract

We did new qualitative and statistical analysis of 59 palaeoecological records across South-East Asia to show that, instead of swings between open savanna and dense, ever-wet rain forest ecosystems, the climatic changes of the Last Glacial Period and particularly the Last Glacial Maximum, involved more fluid transitions between lowland rainforest, seasonally dry ‘savanna’ forest, and tropical montane forest. This ‘hybrid’ forest-savanna biome provides a route beyond currently accepted notions of binary ecologies for the region, and yields new insights into ecological resilience of this region in the past and future.

Scripts

• SavannaCorridorGithub.R

Data

Site-specific palaeoecological proxy series (raw data)

• G6-4.csv
• SH19014_grass.csv
• G5_6_149P2.csv
• NPK2.csv
• hordorli.csv
• 18300.csv
• 18323.csv
• 18302.csv
• CB19.csv
• MD063075.csv
• NS-0725.csv
• 17964.csv
• DDA.csv
• G4_K12P1.csv
• PB-A.csv
• GEOB100693.csv
• PSS.csv
• GeoB100537.csv
• G5_2_056P.csv
• LL2.csv
• RD-3.csv
• KUM3.csv
• G4_K4P3.csv
• BYK2.csv
• TOW9.csv
• BJ8_03_91GGC.csv
• MAT10_2B.csv
• SO189_144KL.csv
• MC1.csv
• mbelen.csv

Compiled, age-resampled, standardised compilation of time series (34 ka to 2 ka), with site coordinates (lon/lat)

• SC_all_SACor.csv

Spatially constrained bivariate correlations to reproduce site-by-site correlation heatmap

• cor_matrix_allmean.csv

Supplementary data

• database descriptors (Excel file)

R packages

Scripts require following R libraries

• spatstat
• gstat
• maps
• sp
• ape
• permute
• ggplot2
• dplyr
• boot
• tmvnsim
• wCorr
• hrbrthemes