Climate Vulnerability Assessment of the Espeletia Complex on Páramo Sky Islands in the Northern Andes uri icon

abstract

  • Some of the largest impacts of climate change are expected in the environmentally heterogeneous and species rich high mountain ecosystems. Among those, the Neotropical alpine grassland above the tree line (c. 2,800 m), known as Paramo, is the fastest evolving biodiversity hotspot on earth, and one of the most threatened. Yet, predicting climate responses of typically slow-growing, long-lived plant linages in this unique high mountain ecosystem remains challenging. Here we coupled climate sensitivity modeling and adaptive potential inferences to efficiently assess climate vulnerability ofEspeletia, Paramo's most iconic, predominant and rapidly evolving plant complex. In order to estimate climate sensitivity, we first modeled the distribution of 28Espeletiataxa under a niche conservatism scenario using altitude and five current (1970-2000) and future (2050 RCP 8.5) bioclimatic variables across 36 different Paramo complexes in the northern Andes (49% of the world's Paramo area). As an alternative to range shifts via migration, we also computed the adaptive capacity of these Paramo complexes by considering three enhancing factors of the biodiversity's adaptive potential as well as three environmental limiting factors of the populations' plastic response. These predictors showed that diverse Paramos in the Eastern Cordillera were more vulnerable likely because the counteracting effects of the adaptive potential (r= -0.93 +/- 0.01) were not sufficient to buffer higher distribution losses (r= 0.39 +/- 0.01). Agriculture (r= -0.48 +/- 0.01), mining (r= -0.36 +/- 0.01), and rural population density (r= -0.23 +/- 0.01) also weakened the adaptive capacity. These results speak for a limited persistence via migration in the short-term responses ofEspeletiato climate change, even though the past population dynamics in concert with glacial cycling is indicative of a predominant role of range shifts. Furthermore, changing climate, together with a general inability to adapt, may eventually constrain the rapid diversification in theEspeletiacomplex. Our integrative modeling illustrates how future climate may impact plant populations in a mega diverse and highly threatened ecosystem such as the Paramo, and encourages carrying out similar estimates in diverse plant complexes across other high mountain and island-like ecosystems.

publication date

  • 2020
  • 2020