Corresponding author: José Paulo Santana (
Among the various applications of phytosociology, the evaluation of natural regeneration is of great importance, mainly because it provides insights for ecological restoration. The objective of this study was to analyze the composition and phytosociological parameters of shrub and tree vegetation in areas of plantation of eucalyptus (
Entre as várias aplicações da fitossociologia, a avaliação da regeneração natural possui grande importância, principalmente porque fornece subsídios para restauração ecológica. Diante disso, este trabalho foi realizado com o objetivo de analisar a composição e os parâmetros fitossociológicos da vegetação arbustivo-arbórea em áreas de plantio de eucalipto (
Phytosociological studies are fundamental to analyze the structure and composition of plant communities, allowing a better understanding of the relationships between plants. In these studies, it is also possible to evaluate the distribution pattern, the importance and the ecological groups of the species in order to identify the successional stage of the community, which in turn can be indicative of conservation status (
Many authors emphasize the importance and necessity of studying the many applications of phytosociology in the evaluation of natural regeneration. This evaluation assumes great importance given the necessity of information on the restoration of native vegetation, particularly for the sub-forest of exotic-homogeneous settlements and of fast growth such as eucalypt (
Although abandoned eucalyptus plantations may have good recolonization rates, it is important to understand which native species are critical to recovering these degraded sites. Further studies are needed to investigate the real contribution of native species to the natural regeneration of these sites. For instance, not all native species can colonize areas containing eucalyptus, because
Little is known about how many areas can be permeable to the arrival of species and how long it takes for their structural recovery. However, some authors indicate that the success of the rapid recovery of the natural vegetation in these eucalyptus sub-forest areas has been associated with the proximity of a source of propagules and the maintenance of the seed bank (
Most of the studies on natural regeneration in the sub-forest of homogeneous exotic plantations are concentrated in the southeastern region of Brazil, especially in the states of Minas Gerais and São Paulo (
In Sergipe, the cultivation of
Among the conservation units in Sergipe lacking in phytosociological studies, is the National Forest (
Considering the above, the objective of this study was to compare the composition and structure of two forest fragments, one in a managed area (
The study area is located in the municipality of Nossa Senhora do Socorro, in the state of Sergipe, northeastern Brazil. The Ibura
In general, the vegetation of the Ibura National Forest is composed of two large sets of formation types: a preserved forest area and an area under regeneration. The preserved forest area shows a dense canopy in an advanced state of succession when compared to other subareas and has an extension of approximately 55.52 ha (38% of the total). The area under regeneration has an understorey in secondary succession mixed with old plantations of
This Ibura
Characterization of vegetation and location of the study area, Ibura National Forest (
The following two sites were selected for the phytosociological survey: (i) preserved forest and (ii) forest in regeneration under stands of
Species identification was performed considering the material deposited in the herbarium ASE (Federal University Sergipe) after the floristic study conducted at Ibura
The successional stage of the studied areas was defined using a subjective criterion to classify species and individuals in ecological groups, according to the model suggested by
Classical phytosociological parameters were estimated only for living individuals, such as relative density, relative frequency, dominance, absolute dominance (total basal area), and the importance value index (
In total, 1,783 individuals were sampled of which 804 were in the Forest area and 979 were in the eucalyptus area. The values of abundance between the plots of the forest area and eucalypt were significantly different (t = -2.6768; p<0.05). There were 102 dead individuals distributed between the two areas, with most of the deaths recorded (66 individuals) in the forest area. There were 84 species of living organisms from 67 genera. The areas showed a significant difference in the species richness (w = 87.5, p < 0.01), with 61 in the eucalyptus area and 65 in the Forest area; only 40 species were common to both areas (Table
List of living individuals by order of
Species |
|
Native Forest | Ab |
|
|
|
|
||||
---|---|---|---|---|---|---|---|---|---|---|---|
Regeneration | Native Forest | Regeneration | Native Forest | Regeneration | Native Forest | Regeneration | Native Forest | Regeneration | |||
|
72 | 123 | 8.77 | 12.28 | 3.67 | 5.07 | 8.53 | 4.81 | 6.99 | 7.39 | |
|
24 | 121 | 2.92 | 12.08 | 3.67 | 4.56 | 13.25 | 6.04 | 6.61 | 7.56 | |
|
42 | 71 | 5.11 | 7.09 | 3.67 | 4.56 | 10.45 | 6.01 | 6.41 | 5.89 | |
|
59 | 34 | 7.18 | 3.39 | 4.08 | 4.06 | 4.06 | 1.66 | 5.11 | 3.04 | |
|
68 | 111 | 8.28 | 11.08 | 4.08 | 5.07 | 1.54 | 2.21 | 4.63 | 6.12 | |
|
37 | 12 | 4.50 | 1.19 | 4.08 | 3.55 | 2.42 | 0.45 | 3.67 | 1.73 | |
|
48 | 10 | 5.84 | 0.99 | 2.04 | 1.52 | 1.49 | 0.16 | 3.12 | 0.89 | |
|
36 | 38 | 4.38 | 3.79 | 2.85 | 3.55 | 1.45 | 0.85 | 2.89 | 2.73 | |
|
20 | 1 | 2.43 | 0.10 | 2.85 | 0.50 | 2.95 | 0.01 | 2.74 | 0.20 | |
|
25 | 20 | 3.04 | 1.99 | 2.44 | 4.06 | 2.49 | 1.34 | 2.66 | 2.46 | |
|
31 | 189 | 3.77 | 18.88 | 2.04 | 5.07 | 1.98 | 8.80 | 2.60 | 10.92 | |
|
29 | 5 | 3.53 | 0.50 | 2.44 | 1.52 | 1.56 | 0.26 | 2.51 | 0.76 | |
|
32 | 3 | 3.89 | 0.30 | 2.04 | 1.01 | 1.41 | 0.12 | 2.45 | 0.47 | |
|
23 | 35 | 2.80 | 3.49 | 3.67 | 3.04 | 0.84 | 0.59 | 2.44 | 2.38 | |
|
25 | 19 | 3.04 | 1.89 | 2.85 | 3.04 | 1.35 | 0.42 | 2.41 | 1.78 | |
|
17 | 2 | 2.07 | 0.20 | 2.04 | 1.01 | 2.74 | 0.03 | 2.28 | 0.41 | |
|
9 | 0 | 1.09 | 0.81 | 0 | 4.79 | 0 | 2.23 | 0 | ||
|
21 | 2 | 2.55 | 0.20 | 2.85 | 1.01 | 0.84 | 0.04 | 2.08 | 0.42 | |
|
19 | 37 | 2.31 | 3.69 | 2.04 | 4.06 | 1.81 | 1.15 | 2.05 | 2.96 | |
|
11 | 3 | 1.34 | 0.30 | 2.04 | 1.52 | 2.60 | 0.03 | 1.99 | 0.61 | |
|
9 | 0 | 1.09 | 0.81 | 0 | 3.12 | 0 | 1.68 | 0 | ||
|
13 | 1 | 1.58 | 0.10 | 2.44 | 0.50 | 0.94 | 0.008 | 1.65 | 0.20 | |
|
7 | 7 | 0.85 | 0.69 | 1.63 | 0.50 | 1.93 | 0.60 | 1.47 | 0.60 | |
|
5 | 13 | 0.60 | 1.29 | 1.63 | 2.53 | 2.10 | 3.13 | 1.44 | 2.32 | |
|
11 | 0 | 1.34 | 0 | 2.04 | 0 | 0.72 | 0 | 1.36 | 0 | |
|
10 | 0 | 1.21 | 0 | 2.04 | 0 | 0.67 | 0 | 1.31 | 0 | |
|
8 | 9 | 0.97 | 0.89 | 2.04 | 3.04 | 0.30 | 0.15 | 1.10 | 1.36 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 2.13 | 0 | 1.06 | 0 | |
|
9 | 0 | 1.09 | 0 | 1.22 | 0 | 0.57 | 0 | 0.96 | 0 | |
|
4 | 0 | 0.48 | 0 | 0.40 | 0 | 1.96 | 0 | 0.95 | 0 | |
|
6 | 0 | 0.73 | 0 | 1.63 | 0 | 0.12 | 0 | 0.83 | 0 | |
|
4 | 0 | 0.48 | 0 | 1.63 | 0 | 0.29 | 0 | 0.80 | 0 | |
|
7 | 3 | 0.85 | 0.300 | 1.22 | 1.01 | 0.23 | 0.11 | 0.77 | 0.47 | |
|
6 | 1 | 0.73 | 0.100 | 1.22 | 0.50 | 0.30 | 0.02 | 0.75 | 0.21 | |
|
4 | 0 | 0.48 | 0.000 | 1.63 | 0 | 0.05 | 0 | 0.72 | 0 | |
Undetermined |
|
4 | 1 | 0.48 | 0.100 | 1.22 | 0.50 | 0.36 | 0.01 | 0.69 | 0.20 |
|
2 | 4 | 0.24 | 0.400 | 0.81 | 1.52 | 1.00 | 0.11 | 0.68 | 0.67 | |
|
3 | 0 | 0.36 | 0 | 0.81 | 0 | 0.87 | 0 | 0.68 | 0 | |
|
3 | 0 | 0.36 | 0 | 1.22 | 0 | 0.09 | 0 | 0.56 | 0 | |
|
2 | 9 | 0.24 | 0.899 | 0.81 | 1.52 | 0.46 | 0.64 | 0.50 | 1.02 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 0.27 | 0 | 0.44 | 0 | |
|
2 | 1 | 0.24 | 0.100 | 0.81 | 0.50 | 0.17 | 0.20 | 0.41 | 0.27 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 0.15 | 0 | 0.40 | 0 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 0.09 | 0 | 0.38 | 0 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 0.07 | 0 | 0.37 | 0 | |
|
2 | 0 | 0.24 | 0 | 0.40 | 0 | 0.47 | 0 | 0.37 | 0 | |
|
2 | 0 | 0.24 | 0 | 0.81 | 0 | 0.05 | 0 | 0.37 | 0 | |
|
2 | 1 | 0.24 | 0.100 | 0.81 | 0.50 | 0.05 | 0.16 | 0.37 | 0.25 | |
|
2 | 1 | 0.24 | 0.100 | 0.40 | 0.50 | 0.43 | 0.36 | 0.36 | 0.32 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.53 | 0 | 0.35 | 0 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.28 | 0 | 0.27 | 0 | |
|
1 | 6 | 0.12 | 0.599 | 0.40 | 2.03 | 0.25 | 1.41 | 0.26 | 1.34 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.19 | 0 | 0.24 | 0 | |
|
2 | 13 | 0.24 | 1.299 | 0.40 | 2.03 | 0.06 | 0.43 | 0.23 | 1.25 | |
|
2 | 1 | 0.24 | 0.100 | 0.40 | 0.50 | 0.04 | 0.01 | 0.23 | 0.20 | |
|
2 | 0 | 0.24 | 0 | 0.40 | 0 | 0.03 | 0 | 0.23 | 0 | |
|
1 | 4 | 0.12 | 0.400 | 0.40 | 0.50 | 0.13 | 0.73 | 0.22 | 0.54 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.03 | 0 | 0.18 | 0 | |
|
1 | 6 | 0.12 | 0.599 | 0.40 | 1.52 | 0.03 | 0.35 | 0.18 | 0.82 | |
|
1 | 5 | 0.12 | 0.500 | 0.40 | 1.01 | 0.03 | 0.22 | 0.18 | 0.57 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.02 | 0 | 0.18 | 0 | |
|
1 | 1 | 0.12 | 0.100 | 0.40 | 0.50 | 0.01 | 0.007 | 0.18 | 0.20 | |
|
1 | 0 | 0.12 | 0 | 0.40 | 0 | 0.01 | 0 | 0.18 | 0 | |
|
1 | 1 | 0.12 | 0.100 | 0.40 | 0.50 | 0.009 | 0.06 | 0.18 | 0.22 | |
|
1 | 1 | 0.12 | 0.100 | 0.40 | 0.50 | 0.009 | 0.11 | 0.18 | 0.23 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.05 | 0 | 0.21 | |
|
0 | 2 | 0 | 0.200 | 0 | 0.50 | 0 | 2.54 | 0 | 1.08 | |
|
0 | 11 | 0 | 1.099 | 0 | 1.52 | 0 | 5.03 | 0 | 2.55 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.01 | 0 | 0.20 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.41 | 0 | 0.34 | |
|
0 | 2 | 0 | 0.200 | 0 | 1.01 | 0 | 0.01 | 0 | 0.41 | |
|
0 | 16 | 0 | 1.598 | 0 | 3.55 | 0 | 28.12 | 0 | 11.03 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 4.34 | 0 | 1.65 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.05 | 0 | 0.21 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.02 | 0 | 0.21 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.01 | 0 | 0.20 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.01 | 0 | 0.20 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.01 | 0 | 0.20 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.03 | 0 | 0.21 | |
|
0 | 6 | 0 | 0.599 | 0 | 1.01 | 0 | 0.21 | 0 | 0.60 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.01 | 0 | 0.20 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.02 | 0 | 0.20 | |
|
0 | 4 | 0 | 0.400 | 0 | 1.01 | 0 | 0.12 | 0 | 0.51 | |
|
0 | 1 | 0 | 0.100 | 0 | 0.50 | 0 | 0.06 | 0 | 0.22 |
The Shannon-Wiener diversity index for the total area was low (H’= 3.35 nats/individual) and the general equitability was J = 0.74. It should be noted that the values between the analyzed areas showed a significant difference for H’ (t = -11.587; p < 0.01), with the highest diversity value for the forest area (forest = 3.47, eucalypt = 2.84). Equitability was also higher in the forest area (forest = 0.83; eucalypt = 0.69).
The species presented a different abundance among the compared areas. The following species were observed in the Forest area:
Of the 60 woody species that settled in the sub-forest of the eucalyptus area, 19 did not occur in the forest area. In addition to the formation of two distinct groups (Fig.
The analysis of the ecological groups by individual between the areas showed a predominance of initial secondary individuals (ES: 422 ind.;
Distribution of family and species according to the number of individuals sampled in the two areas analyzed in the National Forest of Ibura, Sergipe, northeastern Brazil.
Distribution of plots in the forest area (●) and in the eucalypt area (○), both located in the National Forest of Ibura, in the state of Sergipe, northeastern Brazil, obtained by Non-Metric Multidimensional Scheduling (
The total basal area is 21.19 m2/ha, and the results are similar when individualized between the analyzed areas (forest = 9.34 m2/ha; eucalypt = 11.85 m2/ha). It should be noted that the basal area value of the eucalyptus area is influenced by the high
The species with the highest relative densities in the forest area were
As for relative dominance, the forest values appear in the following order:
For the results of the importance value, a small variation was found between species in the two areas analyzed, the important forest (VI) species included
The eight species with the highest importance value in the forest area represent 41% of the total VI by species and 44% of the total of individuals for this area. For the eucalyptus area, the eight species accounted for 58% of the total VI per species and 68% of the total for this area.
The heights within the plots varied between 1.30 and 18.0 meters, with the majority of individuals presenting between 4 and 9 m in height. The eucalyptus area presented the majority of individuals between 4 and 6 m, although it was similar to the forest area in the other height classes (Fig.
Distribution of species according to relative density, relative frequency, relative dominance, sampled in the analyzed areas of the phytosociological study in the National Forest of Ibura, Sergipe, northeastern Brazil.
Frequency distribution of height classes (m) of the individuals sampled in the two areas analyzed in the phytosociological study of the Ibura National Forest, Sergipe, northeastern Brazil.
The highest abundance observed for the eucalyptus area resulted from the presence of many young regenerating individuals and/or those of low diameter values. Some of these fine individuals belong to pioneer species, typically found in areas under regeneration, presenting rapid growth and low longevity, which justifies their high abundance in the eucalyptus area, subsidizing the observed difference between areas (
The eucalyptus area presented lower species richness compared to other areas of natural remnants (
The overall value of the Shannon-Wiener index for the Ibura
At least two of the four families with the highest specific richness in this study were also predominant, sometimes reversing the order of importance, in phytosociological studies carried out in other fragments or ecosystems associated with the Sergipe Forest Atlantic (e.g.,
From the analysis of the ecological groups, it was observed that the Ibura
The characterization of the eucalyptus area at a more initial successional stage than the forest area indicates that the successional processes in the 35 year period are insufficient for the Atlantic Forest areas to reach the climax stage. The evolution of these processes is dependent on internal factors (reproductive rate, colonization, competitive success) and external factors (distance between fragment, dispersion between area, low anthropic pressure) (
The estimated total basal area value for the Ibura
In turn, low density species should have limitations for their population growth. It is possible that the selective cut in the area to groups of species considered rare may also limit the population growth of some species. In addition, environmental characteristics that are subject to different types of tensors should be considered as an influence to the structural development of forests and the colonization of species in deforested areas (
The species of highest value of importance (IVI) in the forest area are still the most important in relation to the other phytosociological indexes of this study, mainly the values of density and relative dominance. The
Several approaches suggest the use of eucalypt species (
Finally, it was concluded that the period of 35 years was not sufficient for the recovery of the abandoned area with established planting of eucalyptus. But the eucalyptus plantation favored the arrival of the most common species in the forest area, while many species considered to be rare, as well as late secondary successional species were limited to this forest area. We recommend caution and planning in the use of this exotic homogeneous species. Priority should be given to the planting of native species with high colonization capacity in the recovery of degraded areas.
We thank CNPq for financial support to the first author throughout the research period. E.V.S.O. was supported by CAPES/FAPITEC (#88881.157451/2017-01). We also thank the whole team and employees of the Ibura National Forest, particularly the former manager Ana Carolina Gomes Batista. Our appreciation also goes to the laboratory colleagues of the ASE Herbarium and Conservation Laboratory of the Federal University of Sergipe.