Evaluation of animal and plant diversity suggests Greenland’s thaw hastens the biodiversity crisis

Abstract

Rising temperatures can lead to the occurrence of a large-scale climatic event, such as the melting of Greenland ice sheet, weakening the AMOC and further increasing dissimilarities between current and future climate. The impacts of such an event are still poorly assessed. Here, we evaluate those impacts across megadiverse countries on 21,146 species of tetrapods and vascular plants using the pessimistic climate change scenario (RCP 8.5) and four different scenarios of Greenland’s ice sheet melting. We show that RCP 8.5 emission scenario would lead to a widespread reduction in species’ geographic ranges (28–48%), which is projected to be magnified (58–99%) with any added contribution from the melting of Greenland. Also, declines in the potential geographical extent of species hotspots (12–89%) and alterations of species composition (19–91%) will be intensified. These results imply that the influence of a strong and rapid Greenland ice sheet melting, resulting in a large AMOC weakening, can lead to a faster collapse of biodiversity across the globe.

Reorganization of seagrass communities in a changing climate

“…Therefore, we used range polygons from the IUCN 74 to model present and future distributions of seagrasses under climate scenarios. We assume that this method is valid because of the strong agreement between occurrence data and range polygons in producing highly similar species distribution model outputs in other taxonomic groups 38 , 39 , 75 – 77 . Along these lines, we converted the species polygons into raster format at a grain resolution of 5 arcmin (~9.2 km) and then to points and treat them as real point occurrence records.…”

“…This limit represents the attainable distance of dispersal and ecological limitation for most species. Our approach is commonly used in distribution modelling of other taxonomic groups, such as terrestrial amphibians, birds, mammals, reptiles, lycophytes, flowering plants, ferns and gymnosperms 39 , 85 . By considering these taxonomic groups, we can make more informed decisions about the migration limits of seagrasses, which are typically dispersed over similar distances 86 .…”

“…Model performances were evaluated using the AUC 89 and TSS 90 scores. TSS scores range from −1 to 1 whereas AUC scores range from 0 (prediction of absence) to a maximum of 1 (predicted presence) 89 , 90 with the threshold of good performing models within the 2.5–97.5 percentile range as is common practice 39 , 87 , 90 , 91 .…”

“…Several factors such as scarcity of georeferenced point records, coverage gaps and sampling biases for many regions and clades and lack of analytical tools can constrain research to assess present and future responses of seagrasses to climate change 37 . In the absence of point occurrences, range polygons can be used to model species distributions because they are integrated from point records, expert knowledge of the ecology and distributions of species, local inventories, atlas and literature and yield robust results 38 , 39 . A global analysis of how seagrasses are responding to climate change is timely and necessary to assess the marine ecosystems that are sensitive to changes in community composition as the Earth system undergoes profound change due to human activity 20 .…”