Fig 1.
Critical habitat and data from the U.S. climate resilience toolkit climate explorer [22].
A. All land designated as critical habitat for both plants and animals under the Endangered Species Act is shaded in dark red. While not all endangered species are located on critical habitat, it does provide a rough distribution of endangered species. The light red circles indicate the relative number of plants in each US FWS region, with larger circles indicating a greater number of listed plants. The black outlines are US FWS regions, which are regulatory regions applied to enforcing the ESA. Region 1: Pacific, the largest circle of the map, also includes Hawai’i as well as other Pacific Islands, where most of the listed plants in this region are located. Layers used to create this map are the USFWS Region Layer (https://gis-fws.opendata.arcgis.com/datasets/c9d8cd103c5c444f9f65a1bc0dfe1b95_0/about), the USFWS Critical Habitat Layer (https://ecos.fws.gov/ecp/report/critical-habitat ), and the Base Layer “Outline Map” (https://www.arcgis.com/home/item.html?id=7da16f48c81f448fa972d4a52fdc1e4e). B. “Temperature” is the average daily maximum temperature. Under high emissions, the average daily maximum temperature will increase for most locations in the continental US. “Growing Degree Days” is an estimate of the growth and development of plants. A higher number of growing degree days indicates longer durations of warm conditions. Much like temperature, the number of growing degree days is projected to increase in all areas other than the highest elevations. “Precipitation” is the total precipitation in a year in inches. Total precipitation appears to increase in the North and East but declines in the Southwest. There was no historic data for total precipitation. “Dry days” is the number of days in a year when precipitation is less than .01 inches. Changes in this number indicate trends towards drier or wetter conditions. The dry days data indicates that in regions like the Northwest, while total precipitation may not change or may increase, there will be an increase in dry days throughout the year. Under climate change, there is the potential for not only shifts in the amount of precipitation, but also shifts in the amount of precipitation received at any given time or the form of the precipitation (i.e. snowfall, ice, or liquid rain). The Northeast, Midwest, and Southeast are particularly likely to be affected by these extreme rainfall events. These heavy rainfall events lead to an increased risk of flooding [23, 24].
Table 1.
Species sensitivity factors to climate change.
Fig 2.
Species sensitivity to climate change.
Layers for the map include the USFWS Region Layer (https://gis-fws.opendata.arcgis.com/datasets/c9d8cd103c5c444f9f65a1bc0dfe1b95_0/about), the Base Layer World Topographic Map (https://www.arcgis.com/home/item.html?id=7dc6cea0b1764a1f9af2e679f642f0f5), and the Base Layer World Hillshade (https://www.arcgis.com/home/item.html?id=1b243539f4514b6ba35e7d995890db1d). A) A color-coded map indicating the average sensitivity score for each US FWS region. B) A violin plot of the sensitivity factors within each region, all regions had a mean sensitivity of 4 or higher.
Fig 3.
The Nine Sensitivity factors and their prevalence in each US FWS region.
The nine sensitivity factors and their frequency within each region. A yellow color indicates that the factor scored a “yes” infrequently in that region, while a dark orange indicates that it is a frequent climate change sensitivity factor for that region. Overall, disturbance (n = 699) and injurious species (n = 733) were the most significant risk factors across all regions.
Fig 4.
The response of ESA listed plants and lichens to disturbance.
A majority of plants and lichens were sensitive to disturbance, but almost all had a negative response (n = 534), killing or damaging the plant or its reproductive organs. A small number had a positive response (n = 67), requiring a disturbance to thrive. A larger number had a mixed response (n = 97)- where they may tolerate or require one disturbance but are susceptible to another. Some plants were not sensitive to disturbance so were scored as “not sensitive” (n = 73).
Fig 5.
Is climate change recognized as a threat to endangered plants and lichen, and what actions are being taken?.
A) Depicts results of number of species where climate change was recognized as a threat, not recognized as a threat or there was no threat. Overwhelmingly, climate change is listed as a threat to endangered plants with 89% (691/771) threatened by climate change. B) The frequency that climate change was listed as a threat by region. Most regions discuss climate change as a threat more than half the time. Climate change was identified most frequently as a threat in FWS Region 1: Pacific, with 99.07% of plants listing climate change as a threat, and least frequently in FWS Region 7: Alaska, which only has one endangered plant species. C) Represents if actions against the threat of climate change are being taken to mitigate the impacts. Only 3% (28/771) of endangered plants had direct actions being taken to mitigate the impacts of climate change. A majority of plants have no direct actions taken with either Further Study or No Discussion, together at 95.5% (736/771). D) The frequency of climate change is addressed by region. Only in FWS Region 1: Pacific did a category other than “No Discussion” make up the majority. In FWS Region 1: Pacific, “Further Study” was the most common category at 64.05%. The most common region to have action being taken to address climate change was FWS Region 6: Mountain Prairie at 11.76%.
Table 2.
Actions taken to mitigate climate change.