These three categories are ranked, with the first two indicating concern for species that could be on their way to extinction. Imperiled status indicates reductions in geographic range or population density, while the distinction between lost and extinct is a matter of time and certainty (also see discussion here). Knowing that a species is extinct, never to be seen again, will, in most cases, require decades of searching before scientists and naturalists agree. In contrast, being “lost” means that a species has not been found in last 10 years. It is useful to remember that the designation of lost is a kind of hypothesis, subject to change with additional information, which is of course why we have Rediscoveries as one of our article types.
Amount of search effort is not explicitly considered in the definition of lost species, which simply means that a species has not been documented in the wild within the last decade (Long & Rodríguez 2022; full citation below). The documentation of search effort is of course valuable, and more search effort without a positive observation will generate greater confidence that a lost species might be at risk of extinction (or, extinct) and add urgency to the description of a species as lost.
Long, B. and Rodríguez, J.P., 2022. Lost but not forgotten: a new nomenclature to support a call to rediscover and conserve lost species. Oryx, 56(4), pp.481-482.
There are of course a great many species and lineages for which information on geographic range and occurrence is extremely limited, including but not limited to insects, many groups of fungi, and most microscopic organisms. However, even for groups with extremely limited information, it is important to keep in mind that the definition of a lost species is one for which no records are available during the last decade, either in digitized databases, the published literature, or museum records. Thus there will be many groups of cryptic or poorly-studied organisms for which a substantial fraction of species deserve to be considered lost, by definition, because we do not know where they are, and the review of available evidence for such a group of species should be published as Report. It is also the case that variation in evidence can be considered while reporting on lost species within data-poor groups, such that lost status for species that are known to be the subjects of field search efforts might carry more weight than for species that are rarely looked for.
Publications in JLS can be about any named taxon, which includes species, subspecies, varieties, etc. In contrast, the loss of populations (extirpation) is in principle a natural part of meta-population dynamics. There may be situations in which an un-named but ecologically significant or morphologically distinct suite of populations is lost, and this can be considered; if in doubt, contact us with questions. What about the loss of single populations or groups of populations that are not necessarily morphologically or ecologically distinct? The loss of such populations can also be indicative of range-wide decline, and in this context might suggest that a species should be designated as imperiled in a Report.
We appreciate of course the challenge posed by the vast numbers of undescribed species, and there will likely be cases in which a species has been documented (and lost) but not formally described. With sufficient documentation, such cases can be subjects of Reports.
As with any scientific article, we only ask that authors are clear about the taxonomic authorities they are following, and provide sufficient information and citations that readers will not be in doubt about the lost or extinct taxa in question.
It is possible to report on local or regional losses (including population extirpations), if they suggest that a species (globally) should be a considered imperiled. If local losses do not necessarily suggest a change to global status, then they can be published as a Letter.
JLS is interested in lost species from the modern era dominated by human influence of the earth, also known as the Anthropocene. There are differing opinions on what date should be considered the start of the era, with propositions ranging from the Neolithic Revolution (in the range of 12 - 15,000 years ago), the Industrial Revolution (the year 1800), or the middle of the 20th century, among other dates. Because this is an evolving field, we want to allow flexibility in this issue, and allow authors to consider dates of human impact that are most relevant to different organisms.
Both are of interest, in all cases focusing on Anthropocene or contemporary extinctions, not extinctions from the paleontological record. A Report can include descriptions of status for species that are imperiled, lost, and extinct; and in many cases it will be useful to summarize information on extinctions for a particular lineage or group of species even if those extinctions have been previously well documented but not necessarily in the primary literature.
This is of course the best possible outcome, and we hope that the information published in Reports motivates and facilitates search efforts that lead to this outcome, for which JLS has a dedicated article type: Rediscoveries.
Yes, and we encourage authors to submit these types of articles, as well as opinion pieces or literature reviews, as Letters. We recognize that authors have many venues for these more traditional types of articles, but hope that JLS will be a productive place for these papers as well as the article types that are unique to JLS (Reports and Rediscoveries). For articles on biodiversity decline, we also ask that authors present the results within the context of lost or potentially lost species, such that future studies might use the published information as a baseline for tracking the fate of individual species.