Our results point to a potential change in the conservation status of approximately 90% of Brazilian threatened butterflies, exclusively by applying the IUCN B criterion of geographic range with the use of compiled and properly curated records. Moreover, with the new data presented here, changes in the extent of occurrence (EOO) and area of occupancy (AOO) were reported for most taxa: changes in EOO were reported for 74.1% taxa (with an increase for 46.5% and reduction for 27.6%) and changes in AOO for 77.6% (with an increase for 63.8% and a decrease for 13.8% taxa). Based only on EOO, there is the potential for a change in conservation status category of about 80% of the threatened taxa, with more than half (53.5%) possibly outside the threshold of any extinction risk category (VU, EN or CR). However, based on the AOO, changes were reported for 58.6% of the taxa, all of which will remain in a category of risk of extinction.
Data cleaning has identified 229 records considered to be erroneous or without traceable origin: these data were excluded and should be omitted in future conservation status assessments. Unpublished municipality records increased by 38.5% in relation to the records previously available in the literature, encompassing 212 municipalities. Many other studies containing records of Brazilian threatened butterflies have already provided significant advances on previous assessments (e.g. Dolibaina et al. 2010; Greve et al. 2013; Freitas et al. 2014; Gomes et al. 2014; Kerpel et al. 2014; Bedê et al. 2015; Kaminski et al. 2015).
It is important to mention that, for unpublished records, approximately half come from scientific collections, with the remainder from field observations / personal communications. This reinforces the importance of scientific collections as important data sources for studies related to species conservation, as well as in conservation status assessments (Shaffer et al. 1998; Miller et al. 2007; Dolibaina et al. 2010; Drew, 2011; Meineke et al. 2018; Muniz et al. 2020). Data digitization is extremely important for facilitating access to researchers; however, this kind of action takes time and demands human and financial resources (Dalton 2003; Paknia et al. 2015; Schilthuizen et al. 2015; Meineke et al. 2018; Cobb et al. 2019). In collections where the data is not yet digitized, the information on voucher specimens can be lost forever. In a recent tragic example, the fire at the National Museum of Rio de Janeiro in 2018 resulted in the permanent loss of at least 200,000 specimens of Lepidoptera (Freitas and Marini-Filho 2011; Zamudio et al. 2018), with mere 16.5% of these available online (Hoffmann and Mello-Patiu 2018).
Records from field observations and correspondence with researchers and civil society also brought several new records, mainly through personal communication followed by photographic records from the social network Facebook and citizen science repositories such as iNaturalist. In addition to contributing beautiful images of organisms in nature, amateur photographers also contribute to scientific research related to species conservation (Rosa et al. 2017; Giovos et al. 2019; Wilson et al. 2020).
Each type of data source contributes differently, with the source with the highest number of geographical sites records being found from literature, followed by field observations (personal communication and photos from websites, such as Facebook social network, iNaturalist, Flickr and Biofaces) and finally, specimens in scientific collections. It is important to emphasize that both, literature data and scientific collections will inevitably be exhausted and few or no new records from these sources may be added in future. Clearly, field observation data (with or without image records) obtained from researchers, citizen scientists and data mined from websites, all have extraordinary potential for use in data assessment for conservation.
For some taxa reported in the present study, “current” estimates of EOO and AOO were higher than “previous” estimates, with increases of more than 100% in the EOO and AOO for 11 and six taxa, respectively. Also, based on new records, the EOO has been widely expanded for several species. For example, based on the new records, the EOO of the papilionid Parides bunichus chamissonia (Eschscholtz, 1821), a butterfly known from few restinga sites in southern Brazil, increased from 147.11 km2 to 1,260.97 km2 (757% in increase). Similarly, the EOO for the skipper Zonia zonia diabo Mielke & Casagrande, 1998 (Fig. 1e) increased from 8,439.21 km2 to 279,135.98 km2 (increase of 3208%) and the EOO of the metalmark Joiceya praeclarus Talbot, 1928, increased from 3,151.73 km2 to 1,350,749.59 km2 (an increase of 42,757%) after the inclusion of a new site from Peru. For these and other butterfly taxa, the increase in the EOO brings us new perspectives on a more realistic distribution of these organisms inside and outside Brazil.
Another notable case was observed for the nymphalid Morpho menelaus eberti Fischer, 1962, which was known from only five localities in northeastern Brazil. After checking dozens of specimens, it was found that the populations of this species are not restricted to the northeast of Brazil, but extend from the state of Paraíba to the middle part of Espírito Santo state (southeastern Brazil), expanding to a total of 26 localities (Patrick Blandin pers. comm. 2019; Freitas et al. 2018). In this study, we must make it clear that increases and decreases in EOO-AOO estimates come from the current knowledge of data quality (e.g. unpublished records can increase EOO-AOO, whereas “errors” records were removed and can decrease EOO-AOO) and are not the result of conservation interventions in their natural range areas (for increases of EOO-AOO).
Based on present results, increases in the EOO could result in the exclusion of more than half of the butterfly taxa from the Brazilian Red List, with some possibly falling into low or no risk categories such as “Near Threatened” (NT) and “Least Concern” (LC). However, it is worth noting that the polygons defined by the EOO are unrealistic in terms of the availability of suitable habitats inside them and, ideally, the AOO is a better way to assess the conservation status of butterflies. However, for the application of AOO, it is necessary to have a good biological knowledge of the organism, especially concerning its habitat restrictions (ICMBio 2013; IUCN Standards and Petitions Committee 2019). The lack of biological knowledge added to a few geographic distribution records and the use of 4 km2 grids (as recommended by IUCN) may not reflect the actual area occupied by the taxon and lead to an “inflated” Red List using the criterion B2. Accordingly, based on the estimates of AOO, even with the increases, all taxa present in current Brazilian Red List would fall under some threat category.
Recently, one of the proposed solutions to solve problems related to EOO and AOO estimates for threatened species has been the application of species distribution modelling (see: Jiménez-Alfaro et al. 2012; Marcer et al. 2013; Pena et al. 2014; Syfert et al. 2014; Silva et al. 2020), an approach that may provide more accurate predictive maps and still has the advantage of being low-costwhen compared to genetic and or demographic studies (Araújo et al. 2002; Guisan and Thuiller 2005; Cayuela et al. 2009). Thus, a promising approach is the use of species distribution modeling combined with the EOO polygons. By combining these two methods, besides obtaining new predicted areas of occurrence for each evaluated taxon, relevant information of habitat suitability inside the EOO polygons will be available for a more realistic application of the IUCN criterion of geographic scope (Rosa et al. in prep.).
These updates in the EOO and AOO of Brazilian threatened butterflies have the potential to change the conservation status of most of the currently threatened taxa. However, in some cases these changes could be a result of the current quantity and quality of information and downlistening these butterfly taxa could be premature. Accordingly, the objectives of the present study are to present new acurate data for future conservation status assessments. Also, the results reinforce the importance of compiling and curating data, in addition to field work and demographic studies, for achieving more realistic information about threatened taxa, especially for insects and other invertebrates.