Impacts of anthropogenic climate change on tropical montane forests: an appraisal of the evidence

Abstract

In spite of their small global area and restricted distributions, tropical montane forests (TMFs) are biodiversity hotspots and important ecosystem services providers, but are also highly vulnerable to climate change. To protect and preserve these ecosystems better, it is crucial to inform the design and implementation of conservation policies with the best available scientific evidence, and to identify knowledge gaps and future research needs. We conducted a systematic review and an appraisal of evidence quality to assess the impacts of climate change on TMFs. We identified several skews and shortcomings. Experimental study designs with controls and long-term (≥10 years) data sets provide the most reliable evidence, but were rare and gave an incomplete understanding of climate change impacts on TMFs. Most studies were based on predictive modelling approaches, short-term (<10 years) and cross-sectional study designs. Although these methods provide moderate to circumstantial evidence, they can advance our understanding on climate change effects. Current evidence suggests that increasing temperatures and rising cloud levels have caused distributional shifts (mainly upslope) of montane biota, leading to alterations in biodiversity and ecological functions. Neotropical TMFs were the best studied, thus the knowledge derived there can serve as a proxy for climate change responses in under-studied regions elsewhere. Most studies focused on vascular plants, birds, amphibians and insects, with other taxonomic groups poorly represented. Most ecological studies were conducted at species or community levels, with a marked paucity of genetic studies, limiting understanding of the adaptive capacity of TMF biota. We thus highlight the long-term need to widen the methodological, thematic and geographical scope of studies on TMFs under climate change to address these uncertainties. In the short term, however, in-depth research in well-studied regions and advances in computer modelling approaches offer the most reliable sources of information for expeditious conservation action for these threatened forests.

Variation in echolocation call emission of Neotropical insect-eating bats in response to shifting ambient temperatures

“…These ecosystems are crucial for biodiversity conservation due to high species diversity and endemism (Cadena et al, 2012), where bats are not the exception (Chaverri et al, 2016; Pineda-Lizano & Chaverri, 2022). However, it has been predicted that the Neotropical region will suffer significant climate change-induced shifts in weather conditions of up to 4°C with slight differences between the wet and dry seasons (Ambarish & Karmalkar et al, 2011) and that highland sites may suffer some of the most significant effects on biodiversity (Karmalkar et al, 2008; Mata-Guel et al, 2023).…”

Assessing Conservation Conditions at La Fortaleza de Kuelap, Peru, Based on Integrated Close-Range Remote Sensing and Near-Surface Geophysics

“…Climatological studies document increasing temperature and rainfall in this part of Peru over the past 50 years, with trends varying seasonally and by metric [25]. Interdisciplinary studies are documenting the upward migration of the cloud belt and its consequences [26,27]. Highland farmers are already struggling to schedule their planting and harvest seasons as weather patterns become less predictable.…”

Discordant changes in foliar and reproductive phenology of tropical dry-forest trees under increasing temperature and decreasing wet-season rainfall

“…These seasonally dry forests, characterised by alternating wet and dry seasons that last between four to seven months (Allen et al, 2017), are widespread across sub-Saharan Africa where they are central to biodiversity conservation and people's livelihoods (Siyum, 2020). For example, the seasonally dry montane forests of the Cameroon highlands are some of the most diverse and threatened plant communities in Africa (Cheek et al, 2000), and being montane they may be especially vulnerable to climate change (Salinas et al, 2021;Mata-Guel et al, 2023). These forests provide essential ecosystem services including carbon storage (Cuni-Sanchez et al, 2021), freshwater provision, flood mitigation (Abiem et al, 2023), pollinators and pest control agents of crops (Tela et al, 2021), but are additionally threatened by land use change, overgrazing, fire and bush meat hunting (Cheek et al, 2000;Chapman et al, 2004;Cheek et al, 2021).…”