Earthworm species in native and planted forests in Brazil
Author
Demetrio, Wilian Carlo
Brazilian National Institute for Space Research - INPE, Avenida dos Astronautas 1758, São José dos Campos, São Paulo State, Brazil.
Author
Fonseca, Priscila Mouro Da
Universidade Federal do Paraná, Setor de Ciências Agrárias, Rua dos Funcionários, 1540 - CEP: 80035 - 050, Juvevê, Curitiba-PR, Brazil.
Author
Dudas, Rafaela
Universidade Federal do Paraná, Setor de Ciências Agrárias, Rua dos Funcionários, 1540 - CEP: 80035 - 050, Juvevê, Curitiba-PR, Brazil.
Author
Zagatto, Mauricio G. R.
Universidade de São Paulo / ESALQ, Depto. de Ciência do Solo, C. P. 09, CEP: 13418 - 900 - Piracicaba, SP, Brazil.
Author
Feijoo, Alexander
Universidad Tecnológica de Pereira, Cra. 27 ## 10 - 02, Pereira, Risaralda, Colombia.
Author
Brown, George Gardner
Universidade Federal do Paraná, Setor de Ciências Agrárias, Rua dos Funcionários, 1540 - CEP: 80035 - 050, Juvevê, Curitiba-PR, Brazil. & Embrapa Forestry, Estrada da Ribeira, km 111, CEP: 83411 - 000, Colombo - PR, Brazil.
text
Zootaxa
2023
2023-03-15
5255
1
304
323
http://dx.doi.org/10.11646/zootaxa.5255.1.25
journal article
10.11646/zootaxa.5255.1.25
1175-5326
7744984
D83875A0-EF3A-4C60-996B-34A1AF206356
Ocnerodrilidae
sp.
BRSP0445
,
2 juveniles
in
Araucaria angustifolia
plantation, hand sorting, topsoil (
0-20 cm
), Cap„o Bonito National Forest, Cap„o Bonito-SP (
-23.88169
,
-48.50773
);
March
, 2012;
P. Fonseca
,
M. Zagatto
, colls
.
A total of 1209 earthworms were collected: 158, 111, 201 and 739 individuals (ind.) in Três Barras, Irati, Pirarí do Sul and Cap„o Bonito National forests, respectively. Overall, nine genera and 13 species (four of them new, as of yet undescribed), belonging to five families (
Rhinodrilidae
,
Glossoscolecidae
,
Ocnerodrilidae
,
Benhamiidae
and
Megascolecidae
) were identified (
Table 2
, 3). Eight are native species, including
Andiorrhinus duseni
(Michaelsen)
, a “
minhocuçu
”, i.e., a large earthworm species with>
25 cm
length,
Urobenus brasiliensis
(Benham)
,
Ocnerodrilidae
sp.,
Fimoscolex
n.sp.
,
Glossoscolex araucariaensis
Feijoo & Brown
,
Glossoscolex
n.sp.
1,
Glossoscolex
n.sp.
2 and
Glossoscolex
n.sp.
3. The other five species are exotic and/or cosmopolitan anthropochore (widespread and transported by humans) species:
Amynthas corticis
(Kinberg)
,
Amynthas gracilis
(Kinberg)
,
Metaphire californica
(Kinberg)
,
Dichogaster saliens
(Beddard)
and
Pontoscolex corethrurus
(M̧ller).
Although most of species collected are native, exotic earthworms represented 88% (1076 ind.) of the individuals sampled. The two most common families found were
Megascolecidae
representing 39% of the exotic earthworms collected, and
Rhinodrilidae
with 55% (being 86%
P. corethrurus
) of all individuals sampled. Both families occurred in all sites evaluated (
Table 2
).
Megascolecidae
comprises several genera of Asian earthworms, and the two most frequent species sampled from this family were
A. corticis
and
A. gracilis
, commonly known in
Brazil
as “jumping worms”, both of which are widespread in
Brazil
(
Brown & James 2007
). Both species had already been documented in Brazilian Atlantic Forests, including
Araucaria
forests and
Pinus
spp.
plantations (
Baretta
et al.
2007
;
Bartz
et al.
2013
,
2014b
;
Demetrio
et al.
2018
;
Ferreira
et al.
2018
;
Krabbe
et al.
1993
;
Ortiz 2016
;
Pereira 2012
;
da Silva
et al.
2019
;
Brown & Gabriac, 2021
;
Demetrio
et al.
2022
). The presence of
Megascolecidae
earthworms in all sites indicate that even native forests sampled here are not pristine environments, since these species are usually found living in human-disturbed environments inhabiting the surface soil layer and feeding on organic matter (
Steffen
et al.
2018
).
The species
P. corethrurus
represented most of the individuals sampled (about 48%), but it was found only in
Araucaria
plantations at Irati and at all sites sampled in Cap„o Bonito, where they dominated the earthworm fauna (
Table 2
, 3). This earthworm can be found in basically all tropical regions, also associated with anthropic disturbance (
Taheri
et al.
2018
). In
Brazil
,
P. corethrurus
was already sampled in almost all Brazilian States (
Brown & James 2007
).
The highest local species richness, considering both sampling methods, was observed in Irati which had eight species (
Glossoscolex
n.sp.
1,
Glossoscolex
n.sp.
2,
A. corticis
,
A. gracilis
,
M. californica
,
A. duseni
,
U. brasiliensis
,
P. corethrurus
), followed by Cap„o Bonito with six species (
D. saliens
,
Glossoscolex
n.sp.
3,
A. corticis
,
A. gracilis
,
Ocnerodrilidae
sp.,
P. corethrurus
), Três Barras with five species (
G. araucariaensis
,
Glossoscolex
sp.
,
A. corticis
,
A. gracilis
,
U. brasiliensis
) and Piraí do Sul with four species (
A. corticis
,
A. gracilis
,
A. duseni
,
U. brasiliensis
). Considering the vegetation
type
, in general, native forests and
Araucaria
plantations had higher species richness compared to pine plantations, except in Piraí do Sul where both plantations had two species. Similar to slightly higher species richness in native forest plots (
6 sp.
overall) and tree plantations (6 to 7 spp.) had been observed previously by
Da Silva
et al.
(2019)
at Embrapa Forestry in Colombo, state of
Paraná
, where exotic species also dominated in the pine plots. However, although a considerable number Atlantic Forest fragments have been sampled in
Brazil
(
Demetrio
et al.
2022
), relatively few of them have had sufficient sampling effort to adequately assess species richness (
Brown & James 2007
).
Although the number of exotic and native species were quite similar between the vegetation
types
(except for Cap„o Bonito, dominated by
P. corethrurus
), we observed low species evenness and high dominance of exotic earthworms is almost all sites evaluated. The relative abundance of exotic earthworms ranged from 33 to 100% using hand sorting in Três Barras and Cap„o Bonito pine plantations, and in formalin from 50% to 100% in Irati pine plantations and all Cap„o Bonito sites. Low dominance of exotic earthworms (<50% of individuals collected, hand sorting) was observed in
Araucaria
(42%) and pine plantations (33%, but only three earthworms were found under
Pinus
) at Três Barras, and pine plantations at Irati (41%) and Piraí do Sul (33%, only 6 earthworms collected).
TABLE 2.
Earthworm species, total abundance (number of individuals collected), species richness and percentage of
native and exotic species sampled by hand sorting in each vegetation type in four Brazilian National Forests. NF = native forest; ARA =
Araucaria angustifolia
plantation; PIN =
Pinus
sp.
plantation.
Earthworm species
|
Origin |
Três Barras NF ARA PIN |
NF |
Irati ARA |
PIN |
Piraí do Sul NF ARA PIN |
Cap„o Bonito NF ARA PIN |
Benhamiidae
Dichogaster saliens
|
exotic |
12 |
1 |
Glossoscolecidae
Glossoscolex araucariaensis
|
native |
10 |
14 |
Glossoscolex
n.sp.
|
native |
10 |
Glossoscolex
n.sp.
1
Glossoscolex
n.sp.
2
Glossoscolex
n.sp.
3
|
native native native |
1 4 2 |
Fimoscolex
n.sp.
|
native |
2 |
1 |
Megascolecidae
Amynthas corticis
Amynthas gracilis
Metaphire californica
|
exotic exotic exotic |
11 3 |
24 |
1 |
8 1 |
14 2 |
4 |
47 |
36 |
2 |
31 9 |
21 1 |
3 |
Juveniles |
exotic |
1 |
6 |
1 |
1 |
Ocnerodrilidae
Ocnerodrilidae
n.sp.
|
native |
2 |
Rhinodrilidae
Andiorrhinus duseni
Urobenus brasiliensis
|
native native |
9 |
4 |
2 |
1 1 |
3 |
2 2 |
1 1 |
4 |
4 |
Pontoscolex corethrurus
|
exotic |
3 |
109 |
109 |
252 |
Rhinodrilidae
/
Glossoscolecidae
juveniles
|
? |
5 |
5 |
3 |
1 |
1 |
1 |
Total collected Species richness % native species % exotic species % exotic individuals
|
38 4 50 50 37 |
57 4 75 25 42 |
3 2 50 50 33 |
12 4 50 50 83 |
38 7 57 43 66 |
9 3 67 33 44 |
49 3 67 33 96 |
41 2 50 50 77 |
6 2 50 50 33 |
164 5 20 80 99 |
137 6 33 67 97 |
255 2 0 100 100 |
In general, formalin expulsion collected a lower number of earthworms than hand sorting, as observed previously by
Da Silva
et al.
(2019)
. The efficiency of formalin compared to hand sorting ranged from 0% (no earthworms sampled) in pine plantations up to 82% in the native forest at Três Barras. Only at two sites (native forests at Irati and Piraí do Sul) did formalin expulsion collect more earthworms than hand sorting (192% and 147%, respectively); however, in both cases formalin basically collected only half of the local earthworm species present (
Tables 2
and 3). The differences observed in the sampling methods were expected. In tropical regions the use of hand sorting is recommended combined with chemical extraction, aiming to sample large earthworms (R̂mbke
et al.
2006). But, the efficiency of formalin on earthworm sampling depends on several factors, such as soil moisture during sampling and also the local earthworm assemblage (
Pelosi
et al.
2009
).
Gutiérrez-López
et al.
(2016)
also showed that chemical extraction is less efficient at sampling endogeic earthworms due their low mobility and lack of burrows connected with the soil surface. In our study, 70% of the earthworms collected using formalin were epiendogeic species (
Amynthas
species
and
U. brasiliensis
), which live in the soil-litter interface, confirming previous results of
Da Silva
et al.
(2019)
.
TABLE 3.
Earthworm species occurrence, total abundance (number of individuals collected), species richness and percentage of native and exotic species sampled by formalin extraction in each vegetation type in four Brazilian National Forests. NF = native forest; ARA =
Araucaria angustifolia
plantation; PIN =
Pinus
sp.
plantation.
Earthworm species
|
Origin |
Três Barras NF ARA PIN |
NF |
Irati ARA |
PIN |
Piraí do Sul NF ARA PIN |
Cap„o Bonito NF ARA PIN |
Megascolecidae
|
Amynthas corticis
|
exotic |
21 |
16 |
17 |
19 |
62 |
29 |
25 |
18 |
4 |
Amynthas gracilis
|
exotic |
3 |
1 |
4 |
7 |
3 |
8 |
Metaphire californica
|
exotic |
6 |
1 |
Megascolecidae
juveniles
|
exotic |
2 |
2 |
2 |
Rhinodrilidae
|
Urobenus brasiliensis
|
native |
6 |
9 |
6 |
1 |
4 |
3 |
Pontoscolex corethrurus
|
exotic |
11 |
19 |
83 |
Rhinodrilidae
/
Glossoscolecidae
juveniles
|
? |
1 |
3 |
2 |
2 |
Total collected
|
31 |
29 |
0 |
23 |
27 |
2 |
72 |
31 |
2 |
46 |
42 |
95 |
Species richness
|
3 |
3 |
0 |
2 |
2 |
2 |
3 |
1 |
1 |
4 |
3 |
3 |
% native species
|
33 |
33 |
0 |
0 |
50 |
50 |
33 |
0 |
0 |
25 |
0 |
0 |
% exotic species
|
67 |
67 |
- |
100 |
50 |
50 |
67 |
100 |
- |
75 |
100 |
100 |
% exotic individuals
|
77 |
59 |
- |
100 |
70 |
50 |
94 |
100 |
- |
93 |
100 |
100 |
Both extraction methods collected more juveniles than adult animals (data not shown), however, some species were found using only a specific method, and/or occurred in a single location, while others did not show any preference:
A. corticis
dominated at almost all sites evaluated, except Cap„o Bonito where
P. corethrurus
was more abundant. In general, hand sorting recovered a higher number of species compared to formalin, and several species were only found using this method at particular site, such as
A. duseni
in Três Barras, Irati and Piraí do Sul;
G. araucariaensis
and
Glossoscolex
sp.
in Três Barras;
Glossoscolex
n.sp.
1,
Glossoscolex
n.sp.
2,
Glossoscolex
n.sp.
3 and
P. corethrurus
in Irati;
Fimoscolex
n.sp.
,
D. saliens
and
Ocnerodrilidae
sp. in Cap„o Bonito.
M. californica
was found in native forest and pine plantations in Irati, and was collected only using formalin. This species is known from some South American countries (
Argentina
,
Peru
,
Venezuela
), and in
Brazil
previous studies found this species in the states of
Santa Catarina
,
Paraná
, S„o Paulo,
Rio de Janeiro
,
Minas Gerais
and
Bahia
(
De Assis
et al.
2017
).
All earthworm species observed in this study (except the new ones) had already been documented from the Atlantic Forest region, especially in
Araucaria
forests. Recently,
Brown & Gabriac (2021)
compiled the data regarding earthworm diversity in
Araucaria
forests (native and plantations) from which they reported 39 species (30 native and 9 exotic).Although the four National Forest sites studied here hosted a good number of earthworm species, the high occurrence of exotic individuals indicates a relatively high level of anthropic disturbance in all vegetation
types
sampled, including the native forest. The consequences of exotic earthworm invasion in Atlantic forest sites are still unknown, but similar effects as those found in North American forests may occur in this biome (
Chang
et al.
2021
;
Ferlian
et al.
2018
), particularly where the native earthworms have already disappeared (
Demetrio
et al.
2022
). Nonetheless, where native earthworms are still present, competition may be an important phenomenon also limiting native earthworm species, as can be predicted from these empirical observations on the high abundance of exotic vs. native earthworm species at the national forests studied.