iucn_sim: A new program to simulate future extinctions based on IUCN threat status

Abstract

1. The on-going environmental crisis poses an urgent need for predicting future extinction events, which can aid with targeting conservation efforts. Commonly, such predictions are made based on conservation status assessments produced by the International Union for Conservation of Nature (IUCN). However, when researchers apply these conservation status data for predicting future extinctions, important information is often omitted, which can majorly impact the accuracy of these predictions.2. Here we present iucn_sim, a command line program, which implements an improved approach for simulating future extinctions based on IUCN status data.In contrast to previous approaches, iucn_sim explicitly models future changes in conservation status for each species, based on information derived from the IUCN assessment history of the last decades. Additionally the program considers generation length information when translating status information into extinction probabilities, as intended per IUCN definition.3. The program implements a Markov-chain Monte Carlo estimation of extinction rates for each species, based on the simulated extinctions. These estimates inherently contain the chances of conservation status changes and the generation length of each given species.4. Based on an empirical data example including all birds (class Aves), we find that our improved approach has a strong effect on the estimated species-specific extinction rates as well as on the overall number of predicted extinctions. Using simulated data we show that iucn_sim reliably estimates extinction rates with high accuracy if run for a sufficient number of simulations.2

The past and future human impact on mammalian diversity

“…Using iucn_sim, we estimated status transition rates across the whole class Mammalia and provided our GL estimates for all mammal species for calculating species-specific extinction probabilities for the threatened IUCN categories ( 60 ). These transition rates and extinction probabilities were then used to predict extinctions throughout the next 80 years across 10,000 simulation replicates.…”

Functionally unique, specialised, and endangered (FUSE) species: towards integrated metrics for the conservation prioritisation toolbox

“…included two alternatives: a) IUCN status treated as a relative score as in Pimiento et al (2020), and here scaled between 0 and 1; and b) IUCN status treated as a probability of extinction over a 100 year time interval (Mooers et al 2008). We acknowledge that there are recent advances in translating IUCN status to extinction probabilities (Andermann et al 2020;Davis et al 2018), but here use the probabilities from Mooers et al (2008) as a first pass at the general sensitivity of our focal metrics to IUCN treatment. Weighting by relative score makes no assumptions about extinction risk probabilities and simply provides equal increments for each IUCN status.…”

“…Note that we used risk probabilities from Mooers et al (2008) as a simple demonstration of the sensitivity of our indices to treating IUCN as a non-linearly increasing probability rather than a rank. Given the strong influence of extinction probability in metrics such as EDGE (Mooers et al 2008) and FUSE (this paper), it is obviously vital that extinction probabilities are estimated as accurately as possible in future studies generating extinction probability-weighted metrics such as FUSEP (Davis et al 2018;Andermann et al 2020).…”

EDGE2: advancing the prioritisation of threatened evolutionary history for conservation action

“…The advances in the field of PD conservation have opened up new avenues to produce a mechanistic EDGE metric that also embodies these desirable properties. Relevant developments included the quantification of extinction risk [42,45], the incorporation of uncertainty in both phylogeny [22,26,46] and extinction risk [47,48], and the concept of phylogenetic complementarity between species [40,41,49]. Each of these developments indicates a potential weakness in the original EDGE metric and a corresponding opportunity to improve its performance.…”

“…We also propose an ‘EDGE Research List’ for species that are credibly above median EDGE2 but are currently either NE or listed assessed as DD on the IUCN Red List (Fig 3). Given that the GE2 values for DD or NE species under EDGE2 are drawn from all possible values for data-sufficient categories, with a median approximately equivalent to that of VU species [45,64], any EDGE Research species are sufficiently evolutionarily distinct that they would become EDGE species if they were eventually to be assessed (or re-assessed for DD species) as VU or above on the IUCN Red List. We define an ‘EDGE Watch List’ for LC and NT species that rank above median EDGE2 95% of the time despite their low extinction risk, and are therefore responsible for securing large amounts of imperiled PD (Fig 3).…”