Climate change threatens biodiversity in the Tropical Andes hotspot

By: Catalina Gonda

The climate crisis and the biodiversity crisis are two sides of the same coin: ongoing climate change is already affecting biodiversity and ecosystem function globally, while accelerating biodiversity loss compromises our ability to successfully mitigate and adapt to climate change. What’s more, climate change is likely to become one of the most significant drivers of biodiversity loss by the end of this century. An ambitious and coordinated approach is therefore urgently needed to address these problems. 

Wildlife in tropical montane areas is particularly at risk since mountains are heating up faster than lowland areas. Additionally, many of the species living there are adapted to very specific – often extreme – conditions and encounter several barriers that limit their capacity to escape to more suitable habitats amid environmental changes.

Such is the case of the Tropical Andes, a region extending from western Venezuela to the north of Argentina and covering large portions of Colombia, Ecuador, Peru and Bolivia. These mountains are arguably one of the world’s leading biodiversity hotspots. They support an exceptional number of species – many endemic – including 15 percent of all known plant species and 12 percent of all vertebrate species known to date, in a region covering only 1 percent of Earth’s land surface. 

Yet, during the last century human activities have transformed a significant portion of this natural landscape, leading to severe habitat degradation, biodiversity loss and disruption of ecosystem functions. Estimates point out that only a quarter of its original natural habitats remain intact. In addition to this significant land-use change pressure, Andean ecosystems are highly sensitive to climate change. 

Today, over 100 million people depend on the ecosystem services the Tropical Andes provide, including freshwater, food and fibre supply, energy production, and many other goods and services. Understanding the potential impacts of climate change in this natural area is therefore critical, as ongoing human-driven biodiversity loss could become further exacerbated by this phenomenon during the next decades.

With the collaboration and support of AirClim, the Environment and Natural Resources Foundation (FARN, Argentina) has developed a comprehensive scientific overview of climate change impacts on Tropical Andean biodiversity, drawing attention to the importance of these ecosystems for the success of climate action. 

The report highlights that ongoing changes in temperature and rainfall patterns are already disrupting a wide range of natural processes in the Tropical Andes, putting biodiversity and the key services it supports at risk. Due to its complex topography, climate and its extraordinary variety of habitats, different species and biomes are expected to respond divergently to global warming.

Climate change is shifting plant communities towards warm-adapted species – a process termed “thermophilisation” – and pushing forests to migrate upwards. Glaciers are melting at alarming rates, presenting many high-altitude species with rapidly changing habitats. One of the Andes most unique and important ecosystems, the páramos, could potentially shrink in area by around 31 percent by 2050 according to some studies.

Moreover, many species are heading uphill to keep pace with climate change. Shifts in the ranges of species and new environmental conditions are altering the ecological processes that result from species interactions and may also facilitate the spread of invasive species and diseases into new areas. These changes can ultimately lead to population declines and local extinctions.

Local extinction risk is higher for mountaintop species. As temperature rises, the suitable climate ranges for many species shift upslope and gradually start shrinking. When cool-adapted summit species cannot shift further, as they have nowhere left to go, mountaintop extinctions occur.

Failing to limit global warming to 1.5°C above pre-industrial levels would have devastating and irreversible consequences for biodiversity and ecosystem function, not only in the Tropical Andes, but worldwide. Biodiversity is essential to maximising the resilience and adaptive capacity of societies and ecosystems. At the same time, natural ecosystems play a fundamental role in climate change mitigation as they sequester carbon in long-lived and relatively stable pools. 

Halting biodiversity loss and protecting the remaining primary and carbon-rich ecosystems in the Tropical Andes is therefore the most important and most urgent priority for regional climate change and biodiversity cooperation. 

Catalina Gonda 

The full report is available both in Spanish and English at: Climate change and biodiversity in the Tropical Andes publication: https://farn.org.ar/archives/27623

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