Invasion of the tropical earthwormPontoscolex corethrurus(Rhinodrilidae, Oligochaeta) in temperate grasslands

Abstract

The tropical earthworm Pontoscolex corethrurus (Rhinodrilidae, Oligochaeta) presents a broad distribution (e.g., 56 countries from four continents). It is generally assumed that temperature appears to limit the success of tropical exotic species in temperate climates. However, the distribution range of this species could advance towards higher elevations (with lower temperatures) where no tropical species currently occur. The aim of this study was to evaluate the soil and climatic variables that could be closely associated with the distribution of P. corethrurus in four sites along an altitudinal gradient in central Veracruz, Mexico. We predicted that the distribution of P. corethrurus would be more related to climate variables than edaphic parameters. Five sampling points (in the grassland) were established at each of four sites along an altitudinal gradient: Laguna Verde (LV), La Concepción (LC), Naolinco (NA) and Acatlán (AC) at 11–55, 992–1,025, 1,550–1,619 y 1,772–1,800 masl, respectively. The climate ranged from tropical to temperate along the altitudinal gradient. Ten earthworm species (5 Neotropical, 4 Palearctic and 1 Nearctic) were found along the gradient, belonging to three families (Rhinodrilidae, Megascolecide and Lumbricidae). Soil properties showed a significant association (positive for Ngrass, pH, permanent wilting point, organic matter and P; and negative for Total N, K and water-holding capacity) with the abundance of the earthworm community. Also there seems to be a relationship between climate and earthworm distribution along the altitudinal gradient. P. corethrurus was recorded at tropical (LV and LC) and temperate sites (NA) along the altitudinal gradient. Our results reveal that soil fertility determines the abundance of earthworms and site (climate) can act as a barrier to their migration. Further research is needed to determine the genetic structure and lineages of P. corethrurus along altitudinal gradients.

Harmful or useful? A case study of the exotic peregrine earthworm morphospecies Pontoscolex corethrurus

“…The map shows that it is present not only in tropical regions but also in sub-tropical zones. For instance, Ortiz-gamino et al (2016) recorded its presence in sub-tropical regions of Mexico, at an elevation of 1550-1619 m above sea level (m.a.s.l. ), and an average temperature of 17°± 2, where no other tropical species occur.…”

“…Its abundance is positively affected by organic matter availability Marichal et al, 2010;Ortiz-Gamino et al, 2016), N availability (Li et al, 2010;Marichal et al, 2010) and P availability (Marichal et al, 2011) in the soil. Therefore, this morphospecies prefers rich soils in terms of organic matter and leaf litter (Liu and Zou, 2002;Ganihar, 2003;García and Fragoso, 2003).…”

“…Lastly, P. corethrurus may coexist with other exotic earthworm species (Table 2) such as Dichogaster spp in Brazil and Costa Rica (Lapied and Lavelle, 2003;Nunes et al, 2006), Ocnerodrilus occidentalis and Drawida barwelli in Puerto Rico and Cuba (González et al, 2007;Martinez and Sanchez, 2000) Amynthas gracilis and Octolasion tyrtaeum in Mexico (Ortiz-gamino et al, 2016) and Metaphire houlleti, M. posthuma, Perionyx excavatus and Amynthus alexandri in India (Dey and Chaudhuri, 2014).…”

“…Most of these peregrine earthworm species are well adapted to human transport and can colonize disturbed habitats (Hendrix et al, 2008). Climate may act as a barrier to their dispersal while their abundance may be limited by soil fertility and plant cover quality (Ortiz-gamino et al, 2016). It is also recognized that introduced species may cause changes to the ecosystem to which it has been introduced.…”

Coprolites Production of Native Earthworms in Braquiaria Fields Under Biofertilization

“…Sales [18] observed that in the dry season the soil is more resistant to the deformations caused by the movement of earthworms since a costly effort would be necessary to move through the soil profile. In a study on earthworms in temperate areas, Ortiz-Gamino et al [19], points out that along an altitudinal gradient, the climate can act as a barrier to the distribution of earthworms, and its abundance occurs in a significant way through soil fertility and pasture quality.…”