Measuring resilience and assessing vulnerability of terrestrial ecosystems to climate change in South America

Abstract

Climate change has been identified as the primary threat to the integrity and functioning of ecosystems in this century, although there is still much uncertainty about its effects and the degree of vulnerability for different ecosystems to this threat. Here we propose a new methodological approach capable of measuring and mapping the resilience of terrestrial ecosystems at large scales based on their climatic niche. To do this, we used high spatial resolution remote sensing data and ecological niche modeling techniques to calculate and spatialize the resilience of three stable states of ecosystems in South America: forest, savanna, and grassland. Also, we evaluated the sensitivity of ecosystems to climate stress, the likelihood of exposure to non-analogous climatic conditions, and their respective adaptive capacities in the face of climate change. Our results indicate that forests, the most productive and biodiverse terrestrial ecosystems on the earth, are more vulnerable to climate change than savannas or grasslands. Forests showed less resistance to climate stress and a higher chance of exposure to non-analogous climatic conditions. If this scenario occurs, the forest ecosystems would have less chance of adaptation compared to savannas or grasslands because of their narrow climate niche. Therefore, we can conclude that a possible consolidation of non-analogous climatic conditions would lead to a loss of resilience in the forest ecosystem, significantly increasing the chance of a critical transition event to another stable state with a lower density of vegetation cover (e.g., savanna or grassland).

Niche conservatism drives a global discrepancy in palm species richness between seasonally dry and moist habitats

“…Also, most lineages fail to colonize seasonally dry habitats, suggesting that possible adaptations to increasingly seasonal climate have not been accomplished readily in all palm lineages (but see Bacon et al, ). This result is striking from a conservation standpoint, because dry ecosystems are predicted to expand in response to climate change (Bastin et al, ), and tropical forests are suggested to be more vulnerable to climate change than tropical seasonal ecosystems, such as savannas (Anjos & de Toledo, ). Moreover, seasonally dry palm assemblages are the result of the diversification of different lineages (turnover), rather than a drought‐tolerant subset (nestedness) world‐wide.…”

The Potential for Rapid Evolution under Anthropogenic Climate Change

“…These changes are already having observable effects on biodiversity, including on the distributions and phenotypes of species as well as on the composition of biological communities [2,3]. Though some species will benefit, various modelling studies have predicted catastrophic outcomes for biodiversity overall [4,5], even though many taxa have proven resilient to climate changes (in non-modified habitats) over recent geological history [6]. These modelling projections include large-scale changes, such as the loss of more than half of a species' range for 49% of all insect species, 44% of plants, and 26% of vertebrates [5].…”

The impact of long dry periods on the aboveground biomass in tropical forests: 20 years of monitoring

“…In addition to the long-term increase across out study landscape, our data suggest that mortality rates can also re ect interactions between and forest re ('cascade effect'). Thus, during periods of prolonged droughts [67], mortality itself increases the probability of subsequent tree death by opening up the canopy, with environmental changes within the forest favouring the occurrence of res [31,32]. The opening in the canopy favours the entry of more light inside the forest, with leaves and other combustible material both drying and increasing in abundance [31,32].…”