Amazon's drought survival blueprint hidden in tree family genes
Researchers have cracked how to predict which Amazon forests will survive intensifying droughts by mapping tree genetics across the region. The finding lets policymakers and companies assess climate risk to vast forest areas without expensive field measurements, revealing which regions face the greatest threat from rising water stress.
Originaltitel: Family imprint reveals basin-wide patterns of Amazon forest embolism resistance
Amazonas skogar klassificeras nu efter deras motståndskraft mot torka — en avgörande parameter för att välja vilka regioner som kan upprätthålla produktion och kolinlagring under framtida vattenstress. Uppsala universitet och internationella partner kartlade embolismresistans (Psi 50) — ett mått på trädets förmåga att bevara vattentransport när luftbubblor bildas — över Amazonas bassäng med hjälp av familjeträd-mönster. Studien analyserade 448 skogsplotter och fann att trädfamiljerna uppvisar måttlig fylogenetisk konservativitet; Fabaceae-familjen visar särskilt högt motstånd. Brasiliansk och Guiana Shield återhämtar sig bättre från torka, medan västra Amazonia framstår som betydligt mer sårbar. För investerare i klimatanpassning och skogsresurser signalerar resultaten att framtida produktionsrisker skiljer sig markant mellan regioner — en insikt som påverkar både leverantörsval och långsiktiga infrastrukturplaner i området.
<p>Amazon rainforests face intensifying water stress due to increases in vapour pressure deficit and changing hydrological regimes. Embolism resistance (Psi 50) is a critical metric of tree survival under drought conditions, it is defined as a plant's capacity to resist disruption of xylem water flow due to air bubble formation from water stress. However, measurements of Psi 50 are only available for a limited number of Amazon locations and species. Conversely, data on forest taxonomic composition are abundant across Amazonia, and if Psi 50 is conserved phylogenetically, these data could provide a way to scale-up drought resistance patterns. Here we evaluate Psi 50 measurements across non-flooded Amazonian tree taxa and reveal a moderate phylogenetic signal, with phylogenetic conservatism evident at the family-level. Notably, Fabaceae is amongst the most embolism-resistant tree families in Amazonia. Leveraging the phylogenetic signal we use species composition and tree size data from 448 forest plots across Amazonia to produce a macroecological assessment of Amazonian vulnerability to embolism. The resulting estimate spatial pattern reveals that forests in the Brazilian and Guiana Shield regions, where Fabaceae abundance is high, show strong resistance to embolism. In contrast, tree communities in Western Amazonia appear more vulnerable to embolism, suggesting a reduced capacity to withstand future drought conditions.</p>