The Consequences of Glacier Retreat Are Uneven Between Plant Species

Abstract

Glaciers are retreating worldwide, exposing new terrain to colonization by plants. Recently-deglaciated terrains have been a subject of ecological studies for a long time, as they represent a unique natural model system for examining the effects of global warming associated with glacier retreat on biodiversity and the spatio-temporal dynamic of communities. However, we still have a limited understanding of how physical and biotic factors interactively influence species persistence and community dynamics after glacier retreat and glacier extinction. Using hierarchical joint species distribution models, we integrated data on plant species occurrence at fine spatial scale, spatio-temporal context, environmental conditions, leaf traits, and species-to-species associations in plant communities spanning 0 to c 5,000 years on average after glacier retreat. Our results show that plant diversity initially increases with glacier retreat, but ultimately decreases after glacier extinction. The 22% of plant species non-linearly respond to glacier retreat and will locally disappear with glacier extinction. At the local scale, soil carbon enrichment and reduction of physical (topographic) disturbance positively contribute to distribution patterns in 66% of the species, indicating a strong impact of community-level environmental conditions. Furthermore, positive and negative associations among species play a relevant role (up to 34% of variance) in driving the spatio-temporal dynamic of plant communities. Global warming prompts a shift from facilitation to competition: positive associations prevail among pioneer species, whereas negative associations are relatively more common among late species. This pattern suggests a role of facilitation for enhancing plant diversity in recently ice-free terrains and of competition for decreasing species persistence in late stages. Associated to that, species persisting the most show more “conservative” traits than species of concern. In summary, although plant diversity initially increases with glacier retreat, more than a fifth of plant species are substantially declining and will disappear with glacier extinction. Even for the “winners,” the “victory” is not to be taken for granted due to the negative impact of rising competition. Integrating survey data with hierarchical and network models can help to forecast biodiversity change and anticipate cascading effects of glacier retreat on mountain ecosystems. These effects include the reduction of ecosystem services and benefits to humans, including food production from the pioneer species Artemisia genipi.

Accuracy of mutual predictions of plant and microbe communities varies along a successional gradient in an alpine glacier forefield

“…Microbes may be more responsive to other environmental factors that may act on short term fluctuations such as temperature, which is equally well predicted by the compositions of bacteria, fungi and plants suggesting its common importance in defining the niche of all taxa. Previous studies demonstrated that plants and microbes from different origins may respond to increased temperature variously, thus we may infer that climate change will shift the interactive patterns between species (Rasmussen et al, 2019;Rudgers et al, 2020;Losapio et al, 2021). In addition, pH was better predicted by bacteria and fungi than by plants, indicating that pH is affecting soil microbes more than plants, which is in agreement with previous studies illustrating the importance of pH in affecting microbial communities (Knelman et al, 2012;Shen et al, 2020).…”

Winter Frosts Reduce Flower Bud Survival in High-Mountain Plants

“…In the predicted scenario of climate warming, a high turnover rate in mountain environments is expected [ 94 ]. Models predict that plant diversity will initially increase with the retreat of glaciers because of the upward migration of lower-elevation species.…”

A preliminary investigation of the lichen biota associated with recently deglaciated terrain in southeastern Alaska

“…Research suggests that, as the ice retreats, not all the species associated with glaciers will be able to migrate and colonize suitable habitats nearby (Körner, 2005). For example, Losapio et al (2021) showed that vascular plant diversity would decrease with glacier extinction and about one fourth of plant species would become locally extinct. Losapio et al (2021) further indicated that those plants most in danger from disappearing glaciers are those of the pioneer communities, which, because these are often facilitators of subsequent communities, will lead to extinction cascades.…”

“…For example, Losapio et al (2021) showed that vascular plant diversity would decrease with glacier extinction and about one fourth of plant species would become locally extinct. Losapio et al (2021) further indicated that those plants most in danger from disappearing glaciers are those of the pioneer communities, which, because these are often facilitators of subsequent communities, will lead to extinction cascades. Cryptogams often dominate these pioneer communities and so these would be disproportionally and negatively affected by glacier extinctions.…”