Reservoirs of richness: least disturbed tropical forests are centres of undescribed species diversity

Abstract

In the last few decades, there has been a remarkable discovery of new species of plants, invertebrates and vertebrates, in what have been called the new age of discovery. However, owing to anthropogenic impacts such as habitat conversion, many of the still unknown species may go extinct before being scientifically documented (i.e. 'crypto-extinctions'). Here, by applying a mathematical model of species descriptions which accounts for taxonomic effort, we show that even after 250 years of taxonomic classification, about 3050 amphibians and at least 160 land mammal species remain to be discovered and described. These values represent, respectively, 33 and 3 per cent of the current species total for amphibians and land mammals. We found that tropical moist forests of the Neotropics, Afrotropics and Indomalaya probably harbour the greatest numbers of undescribed species. Tropical forests with minimal anthropogenic disturbance are predicted to have larger proportions of undescribed species. However, the protected area coverage is low in many of these key biomes. Moreover, undescribed species are likely to be at a greater risk of extinction compared with known species because of small geographical ranges among other factors. By highlighting the key areas of undescribed species diversity, our study provides a starting template to rapidly document these species and protect them through better habitat management.

A new diminutive frog species of Adelophryne (Amphibia: Anura: Eleutherodactylidae) from the Atlantic Forest, southeastern Brazil

“…Despite being flagged among the ''biodiversity hotspots'' (Myers et al 2000), this biome is still being degraded at a fast/steady pace (Ribeiro et al 2009). In the last decades many studies have revealed a large underestimation of amphibian species occurring in the Atlantic Forest (Giam et al 2012) and previously unrecognized lineages sometimes >10 millions of years old (e.g. Fouquet et al 2012 …”

The community of arbuscular mycorrhizal fungi in natural and revegetated coastal areas (Atlantic Forest) in northeastern Brazil

“…That is, the undescribed species are likely to have small distributions, are geographically concentrated and possibly already threatened (Pimm et al 2014;Giam et al 2012). For fungi, the situation is even more serious, as we do not know how many species are yet to be discovered.…”

“…The greatest numbers of undescribed species are likely to be in tropical moist forests of the Neotropics, the Afrotropics and Indomalaya with minimal anthropogenic disturbance, and consequently, are less studied and scientifically explored in comparison with other biomes (Giam et al 2012). Nevertheless, few areas are protected in many of these biomes.…”

“…Most of this Atlantic Forest Dominium is now highly fragmented and under anthropogenic pressure. Therefore, undescribed species are subject to a greater risk of extinction in comparison with known species due to many factors, including their occurrence in small geographical ranges (Giam et al 2012). Bever et al (2001) emphasize the need to consider the below-ground organisms as dynamic participants in plant community processes and their diversity as a key component of soil quality.…”

Tropical fungal diversity: closing the gap between species estimates and species discovery

“…Nonetheless, the structural complexity of tropical forests combined with the diversity of niches and warm, moist climates make it a near certainty that large numbers, if not the majority, of undescribed fungal species reside in the tropics (Hawksworth 1993) as has been determined for some vertebrate groups (Giam et al 2012).…”