Fast recovery of soil macrofauna in regenerating forests of the Amazon.

The emergence of secondary forests in deforested tropical regions represents an opportunity to mitigate biodiversity loss and climate change, but there is still debate on how fast and to which level these forests can recover biodiversity. Recent studies have shown that the recovery of plant and vertebrate species richness is relatively fast, but the pace of recovery for other groups remains unclear. Soil macroinvertebrates play critical roles on litter decomposition and seed dispersal, therefore the pace of their recovery has consequences for the entire forest ecosystem. We investigated how fast broad taxonomic groups of soil macrofauna recover in the first 30 years of forest regeneration using forests older than 50 years as reference. We surveyed the number, diversity and abundance of 19 broad taxonomic groups of soil macrofauna in 85 sites located in Brazilian Amazon, covering forests of different ages and clearing frequencies. Forest age and clearing frequency were obtained accurately from Landsat images in forests up to 30 years old. We used regression analysis to determine (a) the effects forest age and clearing frequency on macrofauna groups in secondary forests up to 30 years old; and (b) the changes in macrofauna groups between young forests (up to 10 years old), median age forests (between 10 and 30 years old) and forests older than 50 years. We found that the number and diversity of macrofauna groups recover rapidly in the first 10 years of forest regrowth, but show slower change among older forests. This rapid recovery was also observed in the abundance of several taxonomic groups and for predators and detritivores as functional groups. Forest clearing frequency had no effect on the number or the diversity of macrofauna groups, but the abundance of ants increased as forest was cleared more often. Our results for soil macrofauna align with those in plant and vertebrate studies showing that secondary forests quickly recover a large part of their biodiversity and ecological functions. Therefore, global-scale conservation strategies are needed to ensure the opportunity for secondary forests to grow. ​.

Brasilisia n. gen. and Arraia n. gen., two new genera of Ocnerodrilidae (Annelida, Clitellata, Oligochaeta) from Eastern Amazonia, Brazil.

We describe two new species from two new genera of Ocnerodrilidae from Alcântara and Rosário counties of Maranhão, Brazil. They were collected in very sandy soil in the transition between the Amazonia and Cerrado biomes. One of the species, Brasilisia punki n. sp., is the first report of earthworms of this family with an unusual pattern of genital markings and a gizzard in segment five. The other species Arraia nelmae n. sp. has a gizzard in segment six and a pair of calciferous glands in nine. We also provide an updated key for all genera of Ocnerodrilidae.

Three new species of Holoscolex (Clitellata, Glossoscolecidae) from the Gurupi Biological Reserve, last forest remnant of the Belém Endemism Area, Eastern Amazon.

We describe three new species of the earthworm genus Holoscolex from the Gurupi Biological Reserve in Maranhão state, Brazil. The Reserve, with the Indigenous Territories Awá, Caru, Alto Turiaçu and Alto Rio Guamá represent the last continuous forest remnants of the Belém Endemism Area, the most deforested and threatened area of Brazilian Amazonia. Holoscolex dossantosi sp. nov. has tubercula pubertatis looking like double bands, Holoscolex alatus sp. nov. presents alate tubercula pubertatis, and Holoscolex fernandoi sp. nov. has testis sacs and several intraclitellar atrial glands associated with genital markings between XIX and XXII. The presence of these unusual characters in Holoscolex fernandoi sp. nov. suggests that this species could be an evolutionary transitional stage linking Eudrilidae and more recent Glossoscolecidae genera.

Additions to Andiorrhinus (Turedrilus) (Rhinodrilidae, Clitellata) from Eastern Amazonia.

Two new species of the earthworm family Rhinodrilidae (Clitellata), from Maranhão state, Brazil, were studied by dissection. Andiorrhinus (Turedrilus) miricuri n. sp. is the first record of a big earthworm for this region with three pairs of large spermathecae in segments 7-9 and one pair of tubercula pubertatis bands lateral to b line in XX-XXV. Andiorrhinus (Turedrilus) barrosoi n. sp. lacks spermathecae and has one pair of tubercula pubertatis bands lateral to b line in XX-(1/3) XXIV. The earthworms described are from the most threatened region of Amazonia where 75% of forest cover is already lost. More information is urgently necessary to assess their ecology and vulnerability status.