Quantitative review of state imperiled species acts

This study was recently published in Conservation Letters, which you can read here. Below see interactive maps of our findings.


To combat biodiversity loss in the United States, imperiled species are protected under the federal Endangered Species Act (ESA), which is currently threatenedby political initiatives seeking to weaken it and potentially transfer substantial authority to the states. To assess the conservation capacity of current state laws, we conducted a quantitative analysis of imperiled species protection within all 50 states by compiling data on all state-listed species, ESA-listed species, and IUCN Red List species in each state. We found that currently 16% of ESA-listed speciesand 52% of IUCN imperiled species are not protected by any state law, and if the ESA were repealed these numbers could increase to 73% of ESA-listed species and 81% of IUCN imperiled species unprotected. Although protection varies widely among states, our results suggest that revoking the ESA would be highly detrimental to imperiled species conservation and recovery in the United States

State Listed Species

The total number of species protected in each U.S. state by each state imperiled species act:
(Hover over or click on each state to see the total value)

To get the total number of listed species in each state, we investigated each state imperiled species act (i.e. laws specific to imperiled species, therefore not including game/hunting laws) and recorded species that were legally protected from harm in some capacity.

Now let’s split this into animal and plant species protected in each state

Total animal species protected in each state

Total plant species protected in each state