4.1. Taxonomic Composition
In terms of composition, the diversity of families in Montes de María is similar to those found in other tropical dry forest fragments in Colombia [
59]. Nymphalidae was the most representative family regarding the number of individuals and species recorded in most studies in Colombia. In this sense, in the Patía River basin, Millan
, et al. [
60], Gaviria-Ortiz and Henao-Bañol [
61], and Henao-Bañol and Andrade-C [
62] registered 60 and 90 species, respectively, while [
63] identified 78. In the Magdalena River valley, Peña and Reinoso [
64] found 64 species, while for the Caribbean, Prince-Chacon
, et al. [
65] reported 38. Lamas (2004) stated that Riodinidae has the highest richness after Nymphalidae. However, these groups, together with the Lycaenidae family, have recorded the lowest species richness in other studies of butterflies in the tropical dry forest [
63,
66], mainly due to their small size and dark colors [
67]. In addition, most of the species of these families tend to fly in higher strata and rest in the upper part of the trees, making its capture difficult within the forest [
68].
Biblidinae is the most abundant subfamily with the highest richness. Regarding studies on the richness of this subfamily in dry forest fragments in the Caribbean region, Montero
, et al. [
69] and Vargas Zapata
, et al. [
70] found that their species showed the highest values with 13 and 10 taxa, respectively, contrary to the study reported by Vargas-Zapata
, et al. [
71] in the department of Atlántico with only six species. In this context, Vargas Zapata, Martinez Hernandez, Gutierrez Moreno, Prince Chacon, Herrera Colon and Torres Periñan [
70] point out that the high richness of this subfamily may be related to the ability of its species to use a wide variety of resources in different plant strata. The abundance results of Biblidinae may be related to their larval stage since these groups feed on plants belonging to the Malvaceae, Euphorbiaceae, Moraceae, and Sapindaceae families [
72], typical of these dry ecosystems. Herazo-Vitola, Mendoza-Cifuentes and Mercado-Gómez [
29] point out that the Malvaceae, Sapindaceae, and Euphorbiaceae are of great relevance in terms of richness and dominance in the flora of Montes de María.
4.2. Community Structure Analysis
The results obtained in the current study suggest that, in the event of the transformation of the tropical dry forest of Montes de María by the expansion of the agricultural frontier (crops and pastures), species loss will occur, and, thus, the transformation of the community structure of butterflies in the forest. The regression outcomes and the cluster analyses based on the dissimilarity matrices allowed identifying species assemblages correlated with the geographical distance (m). Preserved forest areas and areas transformed by crops and pastures were found. Three zones were highlighted in the present study: undisturbed forest area, intermediate disturbed area, and disturbed area. The regressions show that forest areas are characterized by having low diversity, increasing in the intermediate disturbed areas and decreasing in the disturbed areas.
These data support the intermediate disturbance hypothesis proposed by Connell [
73], where an increase in diversity is observed in intermediate areas. This pattern in diversity has also been found in humid forests where butterfly diversity values are higher in an intermediate area than in the disturbed forest [
16,
17,
74]. The formation of these species assemblages may be the product of the long history of anthropic transformation that the Coraza reserve has endured in Montes de María. When forest fragments are cleared for cattle grazing or crop cultivation, the habitat for butterflies disappears, leading to the dispersion of species to nearby fragments.
Increases in species richness are often due to the invasion of disturbed areas by generalist and widely distributed species [
19]. According to Vanschoenwinkel
, et al. [
75], diversity increases because many forest species are more tolerant to disturbance than expected by chance. Thus, extinction rates mediated by stochastic events such as crop and pasture implementation are not necessarily deterministic (
i.e., species have similar extinction probabilities). In other words, disturbance can promote alpha diversity under these conditions.
Disturbance was also found to affect another butterfly community structure dimension. Beta diversity decreases as disturbance increases. The forest has higher beta diversity compared to IDA and DA; however, IDA is higher than DA. The diversity homogenization process of the most disturbed communities may result from the ecological filter [
76]. Environmental conditions,
e.g., higher temperature and solar radiation in disturbed areas compared to forest areas can create barriers that prevent not only movement between forest species and disturbed areas but also the formation of communities with some functional traits that increase their tolerance towards more environmentally stressful areas such as pastures and crops [
77,
78]. However, these aspects must be evaluated in-depth, where the functional traits of butterflies and an analysis of their phylogenetic structure can be measured.
The divergence and phylogenetic regularity analysis measured through the taxonomic distinctiveness of the three types of assemblages show no apparent differences among IDA, forest, and DA. However, IDA are slightly more diverse than DA and forest. These outcomes suggest that species of IDA have a slightly higher phylogenetic separation between species or greater evolutionary distances between their taxa than the rest of the assemblages [
79]. Nevertheless, although the IDA assemblage has a higher species richness, the distribution of its species in the higher taxonomic categories (phylogenetic divergence) has a value equivalent to that of the DA assemblage [
79].
Conversely, the low values in the forest indicate that the species are more closely related at lower taxonomic levels (
e.g., several species belonging to the same genus or family). Therefore, these species are more phylogenetically related than those in disturbed areas. This study proposes two arguments to explain the high phylogenetic relationship or a phylogenetic grouping in dry forest butterfly communities [
80,
81]. The first is based on ecological forces such as the ecological or environmental filter, within which the environment is a filter that only allows species with particular traits or phenotypes to establish and persist in the forest [
82]. The second is more evolutive; a phylogenetic conservatism niche was formed, and, therefore, closely related species are more similar in ecological, morphological, and functional traits than distantly related species since they have inherited it from their ancestors [
83].
On the other hand, outcomes from IDA and DA show a community with higher phylogenetic overdispersion,
i.e., with a higher number of less taxonomically related taxa. Webb
, et al. [
84] suggest that overdispersion in communities is mainly the product of competitive exclusion. Mostly taxonomically related species have a higher morphological similarity in their behavior and eating habits. Similar species tend to compete for the same resources when exposed to a new niche. However, those that become the leading taxa have greater ease in adapting to obtain resources more easily, generating exclusion by competition of other phylogenetically related species [
21].
In the case of the Λ+ results, a difference from Δ* is observed, as IDA and the forest area have higher values than DA. The high values of Λ+ are related to an excessive or insufficient representation of some taxonomic groups (irregularities in the taxonomic tree). In IDA and forest, species are concentrated in the subfamilies Charaxinae, Coliadinae, Papilioninae, and Nymphalinae. The low Λ+ values in the disturbed areas indicate that the variance in the distribution of their species in the higher taxonomic categories is lower (lower Λ+ value), which can be reflected in the fact that their species are grouped mainly in Coliadinae. In other words, the supraspecific distribution is more equitable than the assemblages in the areas with intermediate disturbance and the forest [
79]. These results suggest that the species found in the areas with intermediate disturbance show a phylogenetic regularity similar to that of the forest. Therefore, the influence of ecological processes, such as competition, has influenced the under or overrepresentation of taxa from their communities. However, in both cases, it is necessary to analyze functional traits to obtain a higher precision on what ecological or evolutionary processes influenced the butterfly communities in the interior at the two levels of disturbance and the forest.
Another effect of the disturbance on butterflies in dry forests is not only the generation of new communities but also that the species in these assemblages have adapted to their new habitats to such an extent that their distribution is restricted to these new areas, so they no longer occur in the forest.
Biblis hyperia, Eurema daira, Hamadryas feronia, Junonia evarete, Mestra hersilia, Phoebis sennae,
Temenis laothoe, Battus polydamas, Danaus eresimus, Danaus gilippus, and
Dryadula phaetusa are exclusive species in IDA and DA. When a forest is disturbed, species of butterflies sensitive to disturbance tend to disappear, while the more tolerant species persist [
85]. This study suggests that the species of butterflies associated with IDA and DA can be considered tolerant taxa toward extreme anthropic events because they can efficiently take advantage of the resources the environment offers [
86].
An indicative species of the forest area is
Archaeoprepona demophon (Linnaeus, 1758), belonging to the subfamily Charaxinae.
A. demophon prefers decomposing fruits, which is supported by the large number of individuals found in the baited traps. Forests in the study area have species of the Sapindaceae, Moraceae, Anacardiaceae, and Myrtaceae families that produce sweet and edible fruits, which decompose when falling to the ground, and butterflies can absorb their sugars [
60].
Morpho helenor was found inside the forest and depends on little-disturbed stream edges and forest interiors [
60] because it has complex habitat requirements. In addition, species such as
Hamadryas februa februa, Itaballia demophile calydonia, Myscelia leucocyana, Nica flavilla, Siderone galanthis, and
Zaretis ellops were also exclusive to the forest. This can be explained by the availability of resources for adults, host plants for larvae, or the environmental humidity due to nearby water sources [
63] offered by forests, unlike other cover types.
Interestingly, all nine species of butterflies registered as exclusive to the forest showed less than three individuals. According to the scale proposed by Fagua [
87], species with fewer than three individuals are considered rare, and their occurrence is related to discontinuous flight periods or alternate imago emergences in different butterfly species. Master [
88] proposed that the occurrence of rare species within the forest may indicate areas of interest for conservation, suggesting the importance of preserving the dry ecosystems of the Protective Forest Reserve Serranía de Coraza.