Long‐term ecological responses of a lowland dipterocarp forest to climate changes and nutrient availability

Abstract

Summary Understanding the long‐term impact of projected climate change on tropical rainforests is critical given their central role in the Earth's system. Palaeoecological records can provide a valuable perspective on this problem. Here, we examine the effects of past climatic changes on the dominant forest type of Southeast Asia – lowland dipterocarp forest. We use a range of proxies extracted from a 1400‐yr‐old lacustrine sedimentary sequence from north‐eastern Philippines to determine long‐term vegetation responses of lowland dipterocarp forest, including its dominant tree group dipterocarps, to changes in precipitation, fire and nutrient availability over time. Our results show a positive relationship between dipterocarp pollen accumulation rates (PARs) and leaf wax hydrogen isotope values, which suggests a negative effect of drier conditions on dipterocarp abundance. Furthermore, we find a positive relationship between dipterocarp PARs and the proxy for phosphorus availability, which suggests phosphorus controls the productivity of these keystone trees on longer time scales. Other pollen taxa show widely varying relationships with the abiotic factors, demonstrating a high diversity of plant functional responses. Our findings provide novel insights into lowland dipterocarp forest responses to changing climatic conditions in the past and highlight potential impacts of future climate change on this globally important ecosystem.

Impactos De Mudanças Climáticas Para a Fisiologia E Morgologia Vegetal E À Sociedade

“…Eventos de seca, cada vez mais intensos e frequentes serão cada vez mais associados com a mudança em ecossistemas estáveis, como as florestas, onde um processo de redução no número de indivíduos superiores abrirá espaço para outros inferiores, por exemplo, a senescência de árvores abrindo clareiras onde gramíneas ou ervas se desenvolvem (PROHASKA et al, 2023). Sendo assim, uma vez que mais escassas as chuvas, os eventos de seca tornam-se mais frequentes e cada vez mais acentuados, o que por sua vez, causam diversas consequências nos ecossistemas florestais (TIAN-YE et al, 2023).…”

What is in store for the tropical forests of Indo‐Australia?

“…In a new study published in this issue of New Phytologist , Prohaska et al . (2023; 2513–2529) use a 1400 yr old sedimentary record from the Philippines to determine long‐term vegetation responses of lowland tropical forest. Specifically, the study examines the pollen accumulation rates (PARs), leaf wax hydrogen isotopes, and nitrogen and phosphorous availability from sediment cores taken from the Bulusan Lake in the Bulusan Volcano National Park where logging has been strictly regulated.…”