Spatial and temporal changes in the dung beetle diversity of a protected, but fragmented, landscape of the northernmost Neotropical rainforest

Ecological Indicators 111 (2020) 105968

Contents lists available at ScienceDirect

Ecological Indicators journal homepage: www.elsevier.com/locate/ecolind

Spatial and temporal changes in the dung beetle diversity of a protected, but fragmented, landscape of the northernmost Neotropical rainforest

T

⁎

Renato P. Salomãoa, Mario E. Favilaa, , Daniel González-Tokmana,b a b

Red de Ecoetología, Instituto de Ecología A. C. Carretera Antigua a Coatepec 351. El Haya, Xalapa, Veracruz, México 91070, Mexico CONACYT, Mexico

A R T I C LE I N FO

A B S T R A C T

Keywords: Anthropogenic matrix Bioindicator Habitat modification Scarabaeidae Temporal shifts

Studies addressing the temporal changes of ecological communities within fragmented forests transformed into natural protected areas are urgently needed. The creation of the Los Tuxtlas Biosphere Reserve (LTBR) in 1998 stopped the deforestation process of the northernmost tropical rainforest of the Neotropical region, allowing the analysis of the long-term effects on native communities after the halting of habitat fragmentation. We compared the diversity of dung beetles in 11 forest fragments and eight pastures in the LTBR between two periods: 1999–2000, the early years after the creation of the LTBR; and 2016–2017, i.e., 17 years later. Species richness and abundance of dung beetles were similar in both periods, being higher in forest fragments than in pastures; however, the dominant species were different in each period in both forest fragments and pastures. The number of habitat indicator species increased in 2016–2017 compared to 1999–2000, with a high species diversity of forest indicators relative to pasture indicators at both periods. Alpha and gamma diversities were lower in 1999–2000 than in 2016–2017. Beta-diversity at the spatial level was strongly driven by species turnover, which was higher in pastures than in forest fragments. All functional groups (dwellers, rollers, and tunnellers) showed higher abundances in forest fragments than in pastures in both 1999–2000 and 2016–2017 periods. Our results suggest that stopping the fragmentation process in the LTBR has allowed the survival of native dung beetle assemblages, which are undergoing a recovery process of their populations and ecological functions over the years.

1. Introduction Protected areas are one of the most important conservation strategies to reduce the loss of biodiversity and conserve ecological processes in threatened ecosystems (Barlow et al. 2018; Gullison & Hardner 2018). However, nearly 90% of forests are located within anthropized tropical landscapes (Chazdon et al. 2009). In tropical rainforests, protected areas are usually a fragmented region made of forest fragments of different sizes, connectivity levels, and anthropogenic matrices (see Ranta et al. 1998; DeFries et al. 2010; Scriven et al. 2015). Although there are focal data that underline the importance of protected areas for the conservation of biodiversity (Wuerthner et al. 2015; Gray et al. 2016; Ballesteros-Mejia et al. 2018), most of these are short-term snapshots of the ecosystems involved (but see Laurance et al. 2012); thus, the assessment of long-term effects is urgently needed. Long-term studies or intertemporal comparisons of species inventories remains a challenging task due to the difficulty to replicate sample methodologies used in studies conducted many years ago, with objectives that were

⁎

different from the current ones (Cuesta & Lobo 2019). These difficulties have prevented the evaluation of the efficacy of protected areas in highly disturbed habitats. Recent studies highlight an overall trend towards the decline in insect diversity and abundance, which is also affecting protected areas (Hallmann et al. 2017). Insects participate in multiple ecological processes, and their loss has adverse effects on ecosystem functioning (Dirzo et al. 2014) and therefore insect conservation is becoming a prime concern (Hallmann et al., 2017). Among insects, dung beetles (Coleoptera: Scarabaeinae) have a meaningful role in key ecosystem functions like nutrient cycling, secondary seed dispersal, and parasite suppression, providing valuable ecosystem services such as control of parasites and soil fertilization, among others (Nichols et al. 2008). Dung beetles are also one of the most useful indicator groups to evaluate changes in tropical ecosystems, as they are highly sensitive to environmental disturbance (Halffter & Favila, 1993; Spector 2006; Nichols et al. 2007). Dung beetles are intrinsically related to modifications in the composition of plant and animal communities, leading

Corresponding author. E-mail address: [email protected] (M.E. Favila).

https://doi.org/10.1016/j.ecolind.2019.105968 Received 18 June 2019; Received in revised form 22 October 2019; Accepted 25 November 2019 1470-160X/ © 2019 Elsevier Ltd. All rights reserved.

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

(Vega-Vela et al. 2018). The region has records of about 560 bird, 20 mammal, 30 reptile, 20 amphibian, 437 marine fish, and 2,500 vascular plant species (Villaseñor et al. 2018; Ibiología 2019; Naturalista 2019).

to rapid and apparent changes in the assemblage structure (Hanski & Cambefort 1991; Nichols et al. 2007, 2009). Also, there is a strong relation between dung beetles and mammal diversity, since these vertebrates are the primary food suppliers for dung beetles (Nichols et al. 2009; Scholtz et al. 2009; Raine & Slade 2019). The long-term evaluation of dung beetle assemblages contributes to determine which functional groups and services could be altered, lost, or even recovered through time. In southeastern Mexico, Los Tuxtlas harbors some of the last rainforest remnants of the northernmost Neotropical region. Following the deforestation trend of tropical areas in recent decades, Los Tuxtlas suffered severe deforestation during the 20th century (Guevara et al. 2000). This change of land use was part of the “Plan de Desmonte”, a government-led initiative aiming to leverage “idle land” in Mexico. This resulted in the transformation of more than 50% of the original forest cover in Los Tuxtlas, which was replaced mainly by cattle pastures (Dirzo & Gacia, 1992; Guevara et al. 2000; Vega-Vela et al. 2018). To reverse biodiversity loss and disruption of ecological processes in the region, the Los Tuxtlas Biosphere Reserve (LTBR) was created in 1998, leading to a drastic arrest of deforestation practices (Guevara et al. 2000; Vega-Vela et al. 2018; von Thaden et al. 2018). In this study, we aimed to evaluate the effectiveness of the LTBR to maintain the dung beetle assemblage in this landscape, and thus understand whether this conservation strategy serves to conserve biodiversity in this northernmost Neotropical rainforest. Dung beetles were surveyed in Los Tuxtlas region one year after the establishment of the reserve, producing a focal snapshot of the condition of diversity for this indicator group at that time (Favila 2005). The present study aims to compare the dung beetle assemblage from the same sites in LTBR 17 years after this baseline dung beetle survey. We analyzed dung beetles across the two main habitats of the region: forest fragments of different sizes and pastures. Since fragmented landscapes present longterm effects on biodiversity (Bennett and Saunders, 2010; Haddad et al. 2015), we hypothesize that dung beetle assemblage structure (i.e., diversity, abundance, species composition) will differ between the two periods. If the stop of deforestation activities in LTBR has promoted a recovery of biodiversity, we predict that dung beetle diversity and abundance will be higher 17 years after the creation of the reserve than at the moment of the establishment of LTBR. Furthermore, due to the conservation of the LTBR landscape 17 years after its creation, which could favor species recolonization in forest fragments, we expect that the effects of fragment size on dung beetle species richness and abundance will be attenuated when compared to the moment of the establishment of the reserve.

2.2. Sampling Eleven forest fragments and eight pastures that include the San Martín Tuxtla Volcano and the Sierra de Santa Marta (the other nucleus area) that were sampled in 1999–2000 (Favila 2005) were resampled in 2016–2017. Forest fragments and pastures were monthly resampled at each period. The months surveyed were almost the same in 1999–2000 and 2016–2017 (i.e., January in 1999–2000, February in 2016–2017, March, May, June, August, and October in both periods), allowing to compare the dung beetle assemblage between both annual sampling periods. We used the same methodology as in Favila (2005) to collect dung beetles in each forest fragment and pastures. Pitfall traps (11 cm diameter × 7.5 cm depth) were baited with ca. 25 g of human feces or carrion (i.e., fresh fish meat). Each pitfall was filled with ca. 200 mL of 70% alcohol to preserve the collected specimens, covered with a plastic plate to prevent rainfall and leaf litter from falling into the trap. Pitfall traps were set in two groups of four traps per site, with traps spaced out 20 m from each other within each group, being alternately baited with feces and carrion. Each group was spaced out 100 m from the other. Traps were placed at a distance of at least 20 m from the edge of the habitat surveyed (i.e., forest fragment or pasture), which is sufficient to observe clear differences in the dung beetle assemblage of forest fragments and pastures within the LTBR (Favila 2005). Traps were left in place for 48 h in every sampling period. At each period, a total of 912 traps was set (8 traps per site, in 19 sites, which were resampled six times): 528 in forest fragments and 384 in pastures. Specimens were deposited in the entomological collection at the Instituto de Ecología, A.C. Species were classified into functional groups according to resource removal strategies (rollers – telecoprids; tunnellers – paracoprids; dwellers – endocoprids) (Halffter & Edmonds 1982; Scholtz et al. 2009). 2.3. Data analysis We first assessed sampling coverage of the entire landscape and in each site studied during the two periods. Sampling coverage was evaluated using the method developed by Chao and Jost (2012). Sampling coverages were obtained using the iNEXT online software (Chao et al. 2016). The potential of species as indicators of specific land-use categories in each period was tested using the multinomial model developed by Chazdon et al. (2011). This model is based on the relative abundances of species in two distinct land-use categories, namely forest fragments and pastures in this study. This classification model minimizes potential biases due to differences in sampling intensity between the two landuse categories and to insufficient sampling of rare species in each habitat (Chazdon et al. 2011). We applied the liberal threshold of habitat specialization (K), using the “simple majority” rule, with a cutoff point K = 1/2, which is highly sensitive for determining the habitat specificity of a given species. The classification was performed using the CLAM software version 1.0 (Chao & Lins 2011). Diversity metrics (i.e., Hill numbers), which comprise species richness and abundance, were calculated for each site and period, in order to investigate the effects of land-use categories and the two periods on dung beetle diversity. Also, we tested whether land-use categories and periods differed in beta diversity, to assess whether biotic homogenization was strongest among forest fragments or pastures in the periods 1999–2000 and 2016–2017. Therefore, we partitioned diversity into alpha, gamma, and beta components, using the Hill numbers (Jost 2006). We used the diversity components of orders q = 0 (0D, species richness). q = 1 (1D, exponential of Shannon entropy), and q = 2 (2D, inverse of Simpson diversity) (Hill, 1973; Jost 2006). 0D does not

2. Material and methods 2.1. Study area Field work was conducted in the LTBR, located in the state of Veracruz, southeastern Mexico, within the municipalities of Catemaco, Hueyapan de Ocampo, San Andrés Tuxtla, and Santiago Tuxtla (18°20′N-18°43′N, 95°07′W-95°25′W, Fig. 1). The LTBR spans across an area of 155,122 ha and includes three volcanoes: San Martín Tuxtla, Santa Marta, and San Martín Pajapan (Guevara et al. 2004). The LTBR ranges from zero to 1,720 m.a.s.l.; mean annual temperature is 25 °C and precipitation ranges from 1,200 to 4,200 mm, directly related to altitude within the reserve (Gutiérrez-García and Ricker, 2011). The landscape was originally covered by tropical rainforest in lowlands and montane cloud forest in highlands (Guevara et al., 2000, 2004). The forest patches that persist are represented as ca. 2,140 forest fragments, located mainly in the uppermost regions of the reserve (Guevara et al. 2004; Vega-Vela et al. 2018). The landscape matrix in LTBR comprises mainly agricultural land (pastures and fruticulture) (Guevara et al. 2000; Vega-Vela et al. 2018). Between the years 1995 and 2016, the LTBR has recovered approximately 1.55% of its original forest cover 2

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Fig. 1. Location of tropical rainforest fragments where dung beetles were sampled in the LTBR, Veracruz, Mexico. Table 1 Species abundance of dung beetles sampled in forest fragments and pastures in 1999–2000 and 2016–2017, in the LTBR, Veracruz, Mexico. Guilds: Tun = tunneller; Dwe = dweller; Rol = roller. Species

Ateuchus ilaesum Harold Bdelyropsis newtoni Howden Canthidium ardens Bates Canthidium (Canthidium) centrale Boucomont Canthidium (Eucanthidium) pseudoperceptibile Kohlmann & Solis Canthidium (Eucanthidium) pseudopuncticolle Solís & Kohlmann Canthidium sp. Canthon (Glaphyrocanthon) eurycelis Bates Canthon (Glaphyrocanthon) femoralis Chevrolat Canthon (Glaphyrocanthon) subhyalinus Harold Canthon (Glaphyrocanthon) vazquezae (Martínez, Halffter& Halffter) Canthon cyanellus cyanellus LeConte Canthon indigaceus chiapas Robinson Canthon morsei Howden Copris laeviceps Harold Copris lugubris Boheman Copris sallei Harold Coprophanaeus corytus Erichson Coprophanaeus gilli Arnaud Deltochilum (Hybomidium) carrilloi González-Alvarado & Vaz-de-Mello Deltochilum pseudoparile Paulian Deltochilum scabriusculum Bates Dichotomius amplicollis (Harold) Dichotomius colonicus Say Dichotomius satanas (Harold) Eurysternus (Eurysternus) angustulus Harold Eurysternus maya Génier Eurysternus mexicanus Harold Onthophagus asperodorsatus Howden and Gill Onthophagus batesi Howden & Cartwright Onthophagus incensus Say Onthophagus landolti Harold Onthophagus rhinolophus Harold Onthophagus violetae Zunino and Halffter Onthophagus sp. Phanaeus (Phanaeus) tridens Castelnau Phanaeus (Phanaeus) mexicanus Harold Phanaeus (Phanaeus) sallei Harold Phanaeus endymion Harold Scatimus ovatus Harold Uroxys bonetti Pereira & Halffter Uroxys microcularis Howden & Young Uroxys platypiga (Howden & Young)

Resource removal strategy

1999–2000

Total

Habitat preference

Fragment

Pasture

Tun Tun Tun Tun Tun

Generalist Rare Forest Forest NA

30 32 96 350 0

4 0 0 0 0

Tun

Pasture

0

Tun Rol Rol Rol Rol

Forest Rare Rare Rare Rare

Rol Rol Rol Tun Tun Tun Tun Tun Rol Rol Rol Tun Tun Tun Dwe Dwe Dwe Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun

2016–2017

Total

Habitat preference

Fragment

Pasture

34 32 96 350 0

Forest Rare Rare Forest Forest

171 1 9 253 120

0 0 0 0 0

171 1 9 253 120

7

7

NA

0

0

0

283 3 19 10 16

0 0 0 0 0

283 3 19 10 16

NA Rare Rare Forest Rare

0 28 1 60 33

0 0 0 0 0

0 28 1 60 33

Pasture Pasture Forest Rare Rare Rare Rare Generalist NA

22 0 61 28 3 6 35 37 0

35 13 0 0 3 1 0 8 0

57 13 61 28 6 7 35 45 0

Pasture Pasture Rare Generalist Rare Forest Rare NA Rare

54 0 4 65 0 68 7 0 5

31 8 0 7 1 1 0 0 0

85 8 4 72 1 69 7 0 5

Forest Rare NA Rare Rare NA Rare NA NA Pasture Rare Pasture Forest NA NA Rare Rare Rare NA NA Forest Forest Forest

364 6 0 1 24 0 1 0 0 3 2 6 154 0 0 0 0 2 0 0 195 140 144

0 0 0 5 0 0 0 0 0 18 0 18 0 0 0 4 3 1 0 0 0 1 0

364 6 0 6 24 0 1 0 0 21 2 24 154 0 0 4 3 3 0 0 195 141 144

Forest Rare Rare Rare Forest Forest Forest Pasture Rare Pasture Forest Rare Forest Rare Rare Rare NA NA Pasture Rare Rare Rare Rare

195 2 4 0 126 185 91 27 2 20 81 2 451 2 2 0 0 0 105 4 29 1 36

0 1 2 2 0 1 0 30 0 13 1 0 4 0 2 1 0 0 17 3 0 0 0

195 3 6 2 126 186 91 57 2 33 82 2 455 2 4 1 0 0 122 7 29 1 36

3

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

(i.e., forest fragment or pasture). In addition, we used generalized linear mixed models (GLMM) with a negative binomial distribution to analyze the effects of land-use categories and periods on dung beetle expected species richness and abundance per site. We included land-use category as a random effect in the GLMM that analyzed the effect of period, and included the period as a random effect in the GLMM that analyzed the effect of land-use category. Expected species richness was obtained in iNEXT online software (Chao et al. 2016), thus providing a standardized estimate of species richness and avoiding the bias of different sampling coverages among sites. The assemblage parameters were the response variables, and land-use category and period were the predictor variables. In addition, to assess the relationship between the dung beetle assemblage (species richness and abundance) and forest fragment size in the periods 1999–2000 and 2016–2017, we also performed GLM with a negative binomial distribution (abundance) and Poisson distribution (species richness). All models were tested for normality of residuals and the presence of outliers (Cook’s distance greater than 1). Data were analyzed in R version 3.2.0 (R Core Development Team 2015). The G test of independence was used to compare the distribution of dung beetles based on functional groups (i.e., resource removal strategies) in forest fragments and pastures in the two periods. For this test, we used data of species richness and abundance of dung beetles from each functional group. The G test was performed using the desctools library in R version 3.2.0 (R Core Development Team 2015; Signorell 2018). We used the permutational multivariate analysis of variance (PERMANOVA) to statistically compare differences in dung beetle assemblages across land-use categories and periods. We used 9999 permutations to verify the significance of the PERMANOVA models. To assess heterogeneity of multivariate dispersions between land-cover categories and periods, we used the permutational multivariate analysis of dispersion (PERMDISP) using 999 permutations (Anderson 2006). We made pairwise comparisons among treatments using the Tukey post-hoc test. In addition, we performed a non-metric multidimensional scaling (NMDS) to map differences in dung beetle assemblages in sampling sites. The NMDS ordinations were run with 2,500 random restarts. PERMANOVA and NMDS were performed based on the Bray-Curtis distance matrix, which considers species abundances, and on the Jaccard similarity index, which considers species composition (i.e., presence and absence data). The PERMANOVA was performed using the vegan library in R version 3.2.0 (Oksanen et al. 2016; R Core Development Team 2015), the PERMDISP was performed using the permute and lattice libraries in R (Sarkar 2018; Simpson et al., 2018), and NMDS was performed using the Primer software version 6.0 (Clarke & Gorley 2006).

Table 2 Observed species richness (S) and sample completeness of dung beetles in 1999–2000 and 2016–2017, using the sampling coverage approach proposed by Chao and Jost (2012), in forest fragments and pastures in the LTBR, Veracruz, Mexico. Sample completeness of each estimator is indicated in percentage. Site name

Period

Habitat

S

Sampling coverage

Cerro Buena vista

1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017 1999–2000 2016–2017

Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Forest fragment Pasture Pasture Pasture Pasture Pasture Pasture Pasture Pasture Pasture Pasture Pasture Pasture

12 18 10 17 15 18 14 13 13 16 9 11 13 18 15 14 15 15 11 15 11 11 8 2 7 8 6 8 7 2 3 6 1 8

77.72 91.04 70.62 72.18 81.96 75.88 66.98 89.71 99.58 81.13 92.68 74.37 75.97 95.28 48.12 75.32 100 90.85 90.09 95.05 48.45 93.06 65.78 100 48.47 76.40 57.80 57.92 93.70 80 86.59 86.20 100 58.60

Nanciyaga Estación biológica La Cabaña del Tigre Cerro El Gallo Cerro Sonpaso Cerro Jegal Cerro Coyame Pipiapan Acahual Cortez Cerro Megallo Pastizal Velasco Pastizal Cortel Pastizal Tigre Pastizal Megallo Pastizal Pipiapan Pastizal Buena Vista

consider the abundance of the species for the analysis of diversity, assigning a higher weight to rare species relative to 1D (which considers the relative abundance of species), while 2D assigns a higher weight to abundant species (Jost 2006). Diversity numbers were calculated following Marcon & Hérault (2015), which provides a bias correction for incomplete samplings. These analyses were performed using the entropart library in R software version 3.2.0 (Marcon & Hérault 2015; R Core Development Team 2015). Beta diversity was decomposed using Jaccard’s dissimilarity index (Dj) in order to determine the processes shaping the dung beetle assemblages in forest fragments and pastures in 1999–2000 and 2016–2017 (Legendre 2014). Dj represents total beta diversity and incorporates both species turnover, which considers only species replacement, and nestedness or variation in species richness (Legendre 2014). Decomposition of beta diversity was performed considering the species composition of dung beetle assemblages and using the Baselga’s family approach, which calculates dissimilarity according to nestedness (Legendre 2014). We used a binary null-model-based approach of biological communities (Oksanen et al. 2016), which statistically tests whether beta diversity decomposition was by chance. The binary nullmodel-based approach comprised a non-sequential algorithm used for binary matrices that considered species frequencies (Oksanen et al. 2016). This analysis was performed using the vegan and betapart libraries in R version 3.2.0 (Baselga et al. 2018; Oksanen et al. 2016; R Core Development Team 2015). We used generalized linear models (GLM) with a negative binomial distribution (data presented overdispersion, see Zuur et al. 2009) to assess whether the interaction of land-use categories and periods affected dung beetle expected species richness and abundance per site

3. Results In 1999–2000 we sampled 2,194 dung beetles belonging to 33 species; in 2016–2017 we recorded 2,369 dung beetles belonging to 38 species. The dominant species in forest fragments in 1999–2000 were Deltochilum pseudoparile, Canthidium centrale, and Canthidium sp., altogether accounting for 48.09% of the dung beetles sampled in this habitat (Table 1). In 2016–2017, Onthophagus rhinolophus, D. pseudoparile, and C. centrale were the dominant species in forest fragments, representing 40.06% of the total abundance sampled in this habitat (Table 1). In 1999–2000, the most abundant species recorded in pastures were Canthon cyanellus cyanellus, Onthophagus batesi, and Onthophagus landolti, altogether accounting for 58.67% of the dung beetles sampled in this habitat (Table 1). The dominant species in pastures in 2016–2017 were C. c. cyanellus, Eurysternus mexicanus, and Phanaeus endymion, which represented 62.40% of the total abundance (Table 1). In 1999–2000, the average value of the sampling coverage estimator for forest fragments was 77.47%; for pastures, it was 75.39%. In 2016–2017, averages of the estimators for forest fragments was 4

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Fig. 2. Partition of species diversity for dung beetle assemblages recorded in forest fragments and pastures in 1999–2000 and 2016–2017 within the LTBR, Veracruz, Mexico (mean ± 95% confidence intervals). Alpha (A, B, and C), gamma (D, E, and F) and beta (G, H, and I) diversities were analyzed based on species richness (0D), Shannon (1D), and Simpson (2D). Different letters indicate statistical differences.

specialists, representing eight genera: Ateuchus, Canthidium, Canthon, Copris, Dichotomius, Deltochilum, Eurysternus, and Onthophagus (Table 1). There were five indicator species in pastures, belonging to four genera: Canthon, Eurysternus, Onthophagus, and Phanaeus. Twenty-one species were considered too rare to be classified, and only one species was habitat generalist (Copris laeviceps). Nearly 46% of the species that occurred in both 1999–2000 and 2016–2017 changed their habitat specificity. For forest fragments, 17 species were indicators of this land-use category in 1999–2000 and/or 2016–2017, but only three were forest indicator species in both periods: C. centrale, D. pseudoparile, and O. rhinolophus (Table 1). For pastures, seven species were indicators of this land-use category in 1999–2000 and/or 2016–2017, but only three were pasture indicator species in both periods: C. c. cyanellus, Canthon indigaceus chiapas, and O. batesi (Table 1).

Table 3 Decomposition of beta diversity using Jaccard’s dissimilarity (Dj) for dung beetle assemblages in forest fragments and pastures in 1999–2000 and 2016–2017 in the LTBR, Veracruz, Mexico. Habitat

β-turnover

β-nestedness

β-Dj

Forest fragments and Pastures Forest fragments Pastures

0.585 (79.26%) 0.294 (76.47%) 0.666 (94.11%)

0.153 (20.73%) 0.090 (23.52%) 0.041 (5.88%)

0.738 0.384 0.708

84.89%; for pastures, average was 76.52%. In 1999–2000, sampling efficiency in forest fragments ranged between 48.12% and 100% of the estimated species richness; in pastures, sampling efficiency ranged between 48.47% and 100% (Table 2). In 2016–2017, sampling efficiency in forest fragments ranged between 72.18% and 95.28%; in pastures, sampling efficiency ranged between 57.92% and 100% (Table 2).

3.2. Biodiversity metrics and decomposition of beta diversity For forest fragments, alpha diversity (of orders q = 0, 1 and 2) was statistically higher in 2016–2017 than in 1999–2000 (Fig. 2A, B and C). On the other hand, alpha diversity values for pastures were not different between the two periods. Forest fragments showed a statistically higher gamma diversity (for q = 0, 1 and 2) in 2016–2017 than in 1999–2000 (Fig. 2D, E and F). For pastures, gamma diversity was statistically lower in 2016–2017 than in 1999–2000 for q = 1 and q = 2 (Fig. 2E and F). For forest fragments, beta diversity based on q = 1 was statistically higher in 2016–2017 than in 1999–2000 (Fig. 2H). However, for pastures, beta diversity (q = 2) was statistically higher in

3.1. Land-use indicators In 1999–2000 we identified 14 indicator species, most of them being forest specialists (s = 9) belonging to five genera: Canthidium, Canthon, Deltochilum, Onthophagus, and Uroxys (Table 1). Only five species from three genera (Canthidium, Canthon, and Onthophagus) were pasture specialists (Table 1). Twenty-six species were too rare to classify, and two species were habitat generalists (Ateuchus ilaesum and Coprophanaeus gilli). The number of indicator species increased ca. 14% in 2016–2017 compared to 1999–2000. Eleven species were forest 5

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Fig. 3. Expected species richness (A and B) and abundance (C and D) of dung beetles recorded in forest fragments and pastures in 1999–2000 and 2016–2017 in the LTBR, Veracruz, Mexico (mean ± 95% confidence intervals). Different letters indicate statistical differences.

use category and period affected expected species richness (F3,30 = 42.082; p < 0.001), which was statistically higher in forest fragments than pastures, both in 1999–2000 and 2016–2017 (Fig. 3A). Expected species richness was higher in forest fragments than in pastures (Fig. 3B, X21 = 29.311; p < 0.001) but was not statistically different between 1999 and 2000 and 2016–2017 (, X21 = 0.130; p = 0.718). The interaction between land-use category and period affected dung beetle abundance (F3,30 = 37.545; p < 0.001), which was statistically higher in forest fragments than pastures, in both periods (Fig. 3C). Abundance was higher in forest fragments than in pastures (Fig. 3D, X21 = 110.160; p < 0.001). However, there were no statistical differences on species abundance between 1999 and 2000 and 2016–2017 (X21 = 0.096; p = 0.756). There was no statistical relationship between dung beetle species richness and fragment size both in 1999–2000 (F1,9 = 2.105; p = 0.215) and in 2016–2017 sampling (F1,9 = 4.218; p = 0.509). However, there was a significant positive relation between beetle abundance and fragment size in 1999–2000 (F1,9 = 11.291; p = 0.049, Fig. 4), but not in in 2016–2017 (F1,9 = 11.455; p = 0.524).

1999–2000 than in 2016–2017 (Fig. 2I). Species turnover was the main process shaping dung beetle assemblages in the entire landscape of LTBR. However, the turnover component was higher in pastures than in forest fragments (Table 3). Beta diversity (β-Dj) was lower in forest fragments than in pastures (0.384 vs 0.708, respectively, Table 3). However, in both environments, turnover was higher than nestedness (Table 3). The partition of beta diversity in forest fragments did not deviate from a random distribution (turnover: p = 0.599; nestedness: p = 0.599; β-Dj: p = 0.365). However, in pastures the beta component statistically differed from a random distribution (turnover: p = 0.593; nestedness: p = 0.593; β-Dj: p = 0.017). 3.3. Assemblage structure and distribution of functional groups In both 1999–2000 and 2016–2017, most individuals were collected in forest fragments (1999–2000: n = 2,073, s = 29; 2016–2017: n = 2,244, s = 34) compared to pastures (1999–2000: n = 121, s = 14; 2016–2017: n = 125, s = 17). The interaction between land6

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Fig. 4. Relationship between fragment size and dung beetle abundance in forest fragments in 1999–2000 at the LTBR, Veracruz, Mexico.

When dung beetle assemblages were analyzed according to functional groups, the species richness of each group did not differ between forest fragments and pastures in 1999–2000 and 2016–2017 (Fig. 5A, G6 = 5.116; p = 0.529). Considering dung beetle abundances, all functional groups recorded higher abundances in forest fragments than in pastures, both in 1999–2000 and in 2016–2017 (Fig. 5B, G6 = 511.330; p < 0.001). Dung beetle assemblage were statistically different across land-use categories and time periods (abundance: F3,30 = 5.907; p = 0.001; species composition: F3,30 = 7.610; p = 0.001). Land-use categories and periods showed differences in the dispersion of the variance of the abundance (PERMDISP, F3 = 3.249; p = 0.035) and species composition data (F3 = 3.086; p = 0.042). According to abundance data, there was a tendency towards higher dispersion in fragments in 2016–2017 compared to pastures in 1999–2000 and pastures in 2016–2017 (Fig. S1A). According to species composition, there was a tendency towards higher dispersion in pastures in 1999–2000 compared to pastures and fragments in 1999–2000 (Fig. S1B). According to NMDS ordination based both on species abundance (Fig. 6A) and species composition (Fig. 6B), land-use category and period clearly segregated the dung beetle assemblages. Four species occurred in more than half of the fragments in 1999–2000 and 2016–2017 (A. ilaesum, C. centrale, Dichotomius satanas, Uroxys bonetti) (Table 4).

Fig. 5. Functional groups structure based on species richness (A) and abundance (B) of dung beetles in forest fragments and pastures in 1999–2000 and 2016–2017 in the LTBR, Veracruz, Mexico.

4. Discussion

Montes-de-Oca & Halffter 1995), and could explain some of the shifts observed in dung beetle assemblages of LTBR during both analyzed periods. The slight increase in beetle alpha and gamma diversities seems to be favored by the reduction of deforestation and fragmentation in the LTBR since 1998. Our results showed a shift in species composition and the dominant dung beetle species in forest fragments between 1999 and 2000 and 2016–2017. For example, O. rhinolophus, associated with closed-canopy habitats (Halffter et al. 1992; Sarges et al. 2012), was one of the most abundant species in forest fragments in 2016–2017, but not in 1999–2000. The long-term effects of fragmentation, including species extinction and recolonization (Bennett and Saunders, 2010; Haddad et al. 2015), may affect mammal diversity and vegetation structure in remnants in our study area. Changes in vegetation structure and food availability also influence ecological dynamics, thus affecting the dominance of dung beetle species in ecosystems (Hanski & Cambefort 1991; Larsen et al. 2006; Scholtz et al. 2009). Further studies should

Although previous biodiversity surveys have been conducted at LTBR focusing on various animal groups (e.g., birds, butterflies, and mammals; refer to Raguso and Llorene-Bousquets, 1990; Estrada et al. 1994, 1997), to our knowledge this is the first report about changes in assemblage structure of an animal group in a biosphere reserve throughout the years. The establishment of the LTBR led to the recovery of native vegetation, involving the increase of forested area and the reduction of the agricultural matrix (Vega-Vela et al. 2018). In this study, we found that dung beetle assemblages in LTBR changed in both forest patches and pastures over 17 years once the deforestation of this region ceased. Clear differences between the two sampling periods were evident in both species composition and dominant species. In addition, there was an slight increase in dung beetle alpha and gamma diversities through time at forest fragments, which may indicate a recovery of their assemblages. Interspecific competition and the seasonal activity of beetles, which fluctuate from one year to the next, are important factors that affect dung beetle population dynamics (Hanski & Cambefort 1991; 7

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

studies conducted in tropical and subtropical forests of South America (Gasper et al. 2016; Salomão et al. 2019) showed that assemblages with low species richness and many rare species may yield a low sampling efficiency; this may explain our findings in pastures in this study. Similar to our findings in forest fragments, the species composition of dung beetle assemblages also changed in pastures between 1999 and 2000 and 2016–2017. The two dominant species in 1999–2000, O. batesi and O. landolti, were replaced by P. endymion and E. mexicanus in 2016–2017. Curiously, the dominant species in pastures in 2016–2017 have larger body sizes (P. endymion – between 11 and 20 mm; E. mexicanus – between 8.5 and 13.5 mm; see Génier 2009; Moctezuma & Halffter 2017) than the dominant species caught in 1999–2000 (O. batesi – between 5 and 9 mm; O. landolti – between 4.5 and 5.5 mm, refer to Kohlmann & Solís 2001). Previous studies encompassing dung beetles and other insects taxa demonstrate that the effect of toxic substances, such as ivermectin, may be related to individual body size (Kiffney & Clements, 1996; González-Tokman et al. 2017). Our results suggest that in pastures of Los Tuxtlas, dung beetle species of larger body size have a higher physiological resistance to disturbance (including pesticides) than smaller species. Body size is a key factor that influences the ecological services provided by dung beetles (Doube, 1990; Nichols et al. 2008; Braga et al. 2013). Given the increased abundance of large species in pastures of the LTBR in 2016–2017, we can expect that larger amounts of cattle dung are removed, contributing to the maintenance of pastures. Also, in the current study, we observed in pastures of the LTBR 33% of the species that occur in pastures of tropical regions of Mexico (Favila 2012). This finding suggests that LTBR pastures comprise an impoverished assemblage of dung beetle species that may inhabit such ecosystem. Further studies are needed to analyze the effect of ivermectin and other threats on the species diverstiy of dung beetles that inhabit pastures in the LTBR. Interestingly, dung beetle abundance was positively related to fragment size in 1999–2000, but not in 2016–2017. These results suggest that in 2016–2017 there was a higher displacement and colonization of individuals across forest fragments of different sizes than in 1999–200. Furthermore, our results also indicate that these relatively small forest fragments can support a higher abundance of dung beetles through time. Besides, according to diversity numbers, alpha and gamma diversities were higher in 2016–2017 than in 1999–2000. Regions that underwent recent disturbance show a decrease in dung beetle diversity due to the disappearance of sensitive species and decrease of abundance, which may recover through time after the disruptive episode (Quintero & Roslin 2005; Carpio et al. 2009; Hernández et al. 2014). Apparently, this is occurring at our study site, showing an increase in the number of species capable to thrive in the LTBR. Thus, changes in landscape structure (e.g., fragment size and connectivity) are key parameters that may predict the changes in dung beetle diversity observed across the forest fragments analyzed herein. The distribution of dung beetle species is affected by habitat structure (Hanski & Cambefort 1991; Larsen et al. 2006; Nichols et al. 2007; Scholtz et al. 2009). Despite the fragmentation effects on dung beetle assemblages, local species extinctions may be balanced by the colonization of new species that successfully respond to the new environmental conditions (Didham et al. 1998). Our study present cues suggesting that fragmentation effects may change throughout the years in a protected landscape, mitigating the effects of fragment size on dung beetle abundance. A study conducted in the Amazonian forest showed an increase in the abundance of Eurysternus species once deforestation stopped (Quintero & Roslin 2005). Most of these Eurysternus species show increases of their populations in well conserved habitats, such as larger forest patches and conserved forest remnants (Klein, 1989; Gardner et al. 2008; Silva et al. 2014). Eurysternus maya, E. mexicanus, and E. angustulus occur mainly in forested sites in the LTBR, being rare or absent in open areas, except for E. mexicanus, apparently an eurytopic species that can inhabit disturbed sites (Navarrete & Halffter 2008;

Fig. 6. NMDS ordination of the distribution of dung beetle assemblages in the LTBR, based on species abundance (A) and species composition (B) data.

consider evaluating whether other animal assemblages (e.g., mammals) are recovering or diminishing after the cease of deforestation in the LTBR. Pastures yielded a low sampling efficiency in both 1999–2000 and 2016–2017. In general, habitats with low sampling efficiency may indicate that a limited number of species from the total pool is recorded (Gasper et al. 2016; Rajakaruna et al. 2016). Pesticides used in cattle are major drivers of changes of dung beetle biodiversity in pastures, negatively affecting their life cycles and behavior (Cruz-Rosales et al., 2012; Verdú et al. 2015; Alvarado et al. 2017). Ivermectin is a pesticide commonly used in pastures in Mexico (Cruz-Rosales et al., 2012), and could be a main factor affecting sensitive dung beetle species, which may be replaced by more tolerant species. From the species recorded in pastures within the LTBR, 21.42% (1999–2000) and 35.29% (2016–2017) were singleton, while in forest fragments only 6.89% (1999–2000) and 8.82% (2016–2017) were singleton. This may indicate that dung beetle assemblages in the pastures of LTBR are characterized by few and rare species thriving in this ecosystem. Previous 8

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Table 4 Dung beetles sampled in tropical rainforest fragments in the LTBR, Mexico. Each cell indicates the presence (x) or absence (0) of a species in each fragment in a sampling period: xx means that the species was present in 1999–2000 and 2016–2017; x0 indicates that the species was present in 1999–2000 and absent in 2016–2017; and 0x indicates that the species was absent in 1999–2000 and present in 2016–2017. Fragments are ranked according to surface area (30–560 ha). The last column shows the percentage of fragments where a species was captured in both sampling periods (xx). Species / Fragment No. and size (ha)

5 (30)

6 (40)

12 (60)

17 (80)

40 (87)

9 (90)

35 (1 5 6)

18 (2 3 0)

8 (2 8 0)

16 (5 1 0)

34 (5 6 0)

% coincidence

Ateuchus ilaesum Bdelyropsis newtoni Canthidium ardens Canthidium (Canthidium) centrale Canthidium (Eucanthidium) pseudoperceptibile Canthon (Glaphyrocanthon) eurycelis Canthon (Glaphyrocanthon) femoralis Canthon (Glaphyrocanthon) subhyalinus Canthon (Glaphyrocanthon) vazquezae Canthon cyanellus cyanellus Canthon morsei Copris laeviceps Copris lugubris Copris sallei Coprophanaeus corytus Coprophanaeus gilli Deltochilum (Hybomidium) carrilloi Deltochilum pseudoparile Deltochilum scabriusculum Dichotomius amplicollis Dichotomius colonicus Dichotomius satanas Eurysternus (Eurysternus) angustulus Eurysternus maya Eurysternus mexicanus Onthophagus asperodorsatus Onthophagus batesi Onthophagus incensus Onthophagus landolti Onthophagus Rhinolophus Onthophagus violetae Onthophagus sp. Phanaeus (Phanaeus) sallei Phanaeus endymion Scatimus ovatus Uroxys Bonetti Uroxys microcularis Uroxys platypiga % coincidence

xx 0 0 xx 0 0 0 0x 0 0 0 0 x0 x0 0 0 0 0 0 0x x0 xx 0x 0 0 0 0 xx xx 0 0 0 0 0x 0 xx 0 0x 15.78

0x 0 x0 xx 0 0 0 xx 0 0 0 0 0 x0 0 0 0 x0 0x 0x 0 0 0 0 0x 0 x0 0x 0 0 0 0 0 0x 0x 0 0 0 5.26

xx 0x xx xx 0x 0 0 0x 0 0 0 xx x0 xx 0 x0 0 xx 0x 0 0 0x 0x 0x 0 0x 0x xx 0 0 0 0 0 0x 0 xx 0 0x 47.36

xx 0 x0 xx 0x 0x 0x 0x 0 0 xx xx 0 0 0x 0 0 xx 0 0 0 0 0x 0x 0x 0 0 0 0x 0x 0 0 0 0 0 xx 0 0x 15.78

xx x0 x0 xx 0x 0x 0 0 0 xx x0 0x 0 0 0x x0 0 xx 0 0 0 xx 0x 0 0x 0 0x 0 0 xx 0 0 0 0x 0 xx 0 0x 18.42

xx 0 x0 xx 0x 0 0 0 0 0 0 xx 0 xx 0 0 0 x0 0 0 0 0x 0x 0 0x 0 0x 0x x0 0 0 0 0 0x 0x xx 0x 0x 13.15

xx 0 x0 xx 0x 0 0 0 xx 0 xx 0x 0 0 0 x0 0x xx 0 0x 0 0x 0x 0 0x 0 0x 0x 0 xx 0 0 x0 0x 0 xx 0 0x 18.42

xx 0 x0 xx 0x 0 0 0 0 xx x0 xx 0 0 xx x0 0 xx 0 0 0 xx 0 0 0x 0 0x 0x 0 xx 0 0 0 0x 0 x0 0 0 47.36

0x 0 xx xx 0x 0 0 0x 0x 0 x0 0x 0 xx 0 x0 0 xx 0 0 0 xx 0x 0 0x 0 0 0x 0 0 0 0x 0 0x 0 xx 0 0 15.78

xx xx x0 xx 0x 0 0 0 xx 0 x0 0 0 0 0 x0 0x xx 0 0 0 xx 0x 0 0x 0 0 0 0 xx 0x 0 0 0x 0 xx 0 0x 47.36

0x 0 0 xx 0x 0x x0 xx xx xx xx xx 0 0 xx x0 0 xx 0 0x 0 xx 0 0 0 0 xx 0x 0 xx 0 0 x0 0x 0 0x 0 0 28.94

72.72 9.09 18.18 100 0 0 0 18.18 27.27 27.27 27.27 45.45 0 27.27 18.18 0 0 72.72 0 0 0 54.54 0 0 0 0 9.09 18.18 9.09 45.45 0 0 0 0 0 72.72 0 0

results. In the Atlantic rainforest, larger forest fragments showed a lower species turnover of dung beetle species than smaller forest fragments, further supporting the idea that a lower species turnover may be observed in well conserved ecosystems (Filgueiras et al. 2019). On the other hand, the high environmental complexity in forest fragments of the LTBR may be related to the higher equilibrium in the distribution of both turnover and nestedness components found in this habitat compared to pastures. The low environmental complexity in pastures of the LTBR and the harsher environmental conditions in this kind of habitat explain the non-random distribution in pastures. It seems that the movement of individuals is more restricted in pastures than in the forest in the LTBR, favoring species turnover. The modification of land cover and land use seems to be the responsible of the markedly contrasting pattern of beta diversity observed in the LTBR landscape. Protected areas may have a limited effectiveness for attaining the goal of conserving biodiversity (Laurance et al. 2012; Scriven et al. 2015; Borner et al. 2016), failing to promote the reestablishment and maintenance of ecological communities. Such pattern has also been observed in dung beetle assemblages that do not recover throughout time in regions where deforestation has stopped (Escobar et al. 2008; Audino et al. 2014). However, our results show that the protected area of LTBR facilitated the conservation and recovery of dung beetle assemblages, with increased taxonomic and functional diversity over the years. With this information, we highlight the importance of biosphere reserves as a successful strategy for biodiversity conservation in tropical

Génier 2009; Bourg et al. 2016). Notwithstanding, in 1999–2000, Eurysternus was rarely collected in forest fragments and pastures (n = 1) compared with 2016–2017 (n = 334). The reduction of habitat loss seems to directly benefit the distribution and abundance of Eurysternus species through time within the landscape of the reserve. Based on our results, the species of this genus showed the most pronounced recovery among the dung beetle species studied in the LTBR, which may derive from the forest conservation observed in the region, according to Vega-Vela et al. (2018). In addition, all species of Eurysternus were efficient land-use indicators during 2016–2017, suggesting that some genera of dung beetles may be more sensitive to changes in habitat structure than others. Further studies should determine which dung beetle species are the best indicators of the quality of conserved environments. Complex and species-rich environments favor random assemblages, while severe and species-poor environments disrupt the randomness of assemblages (Whittaker 1975). These patterns were observed in the dung beetle assemblages in the LTRB. The partition of beta diversity did not deviate from the expected random assemblage process in forest fragments, but did deviated in pastures. Besides, turnover was higher in pastures than in forest fragments. Tropical forests are diverse ecosystems, with a vast array of microclimatic conditions and abundant food supply favoring not only a high dung beetle diversity (Hanski & Cambefort 1991; Estrada et al. 1999; Nichols et al. 2007), but also a random distribution of populations in the forest, according to our 9

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

rainforests. We recommend conducting further long-term studies involving the use of other indicator groups to assess the success or failure of biosphere reserves to conserve and restore biodiversity in tropical rainforests, a biome that is facing alarming biodiversity losses in the Anthropocene.

reserves: A research agenda for conserving biodiversity in human-modified tropical landscapes. Biotropica 41, 142–153. Chazdon, R.L., Chao, A., Colwell, R.K., Lin, S.Y., Norden, N., Letcher, S.G., Clark, D.B., Finegan, B., Arroyo, J.P., 2011. A novel statistical method for classifying habitat generalists and specialists. Ecology 92, 1332–1343. Cruz-Rosales, M., Martínez, I.M., López-Collado, J., Vargas-Mendoza, M., GonzálezHernández, H., Fajersson, P., 2012. Effect of ivermectin on the survival and fecundity of Euoniticellus intermedius (Coleoptera: Scarabaeidae). Int. J. Tropical Biol. 60, 333–345. Cuesta, E., Lobo, J., 2019. A comparison of dung beetle assemblages (Coleoptera, Scarabaeoidea) collected 34 years apart in an Iberian mountain locality. J. Insect Conserv. 23, 101–110. DeFries, R., Karanth, K.K., Pareeth, S., 2010. Interactions between protected areas and their surroundings in human-dominated tropical landscapes. Biol. Conserv. 143, 2870–2880. Didham, R.K., Lawton, J.H., Hammond, P.M., Eggleton, P., 1998. Trophic structure stability and extinction dynamics of beetles (Coleoptera) in tropical forest fragments. Phil. Trans. Royal Soc. B Biol. Sci. 353, 437–451. Dirzo, R., Gacia, M.C., 1992. Rates of deforestation in Los Tuxtlas, a Neotropical area in southeast Mexico. Conserv. Biol. 6, 84–90. Dirzo, R., Young, H.S., Galetti, M., Ceballos, G., Isaac, N.J.B., Collen, B., 2014. Defaunation in the Anthropocene. Science 345, 401–406. Doube, B.M., 1990. A functional classification for analysis of the structure of dung beetle assemblages. Ecol. Entomol. 15, 371–383. Escobar, F., Halffter, G., Solís, A., Halffter, V., Navarrete, D., 2008. Temporal shifts in dung beetle community structure within a protected area of tropical wet forest: a 35year study and its implications for long-term conservation. J. Appl. Ecol. 45, 1584–1592. Estrada, A., Coates-Estrada, R., Meritt, D.A., 1994. Non flying mammals and landscape changes in the tropical rain forest region of Los Tuxtlas, Mexico. Ecography 17, 229–241. Estrada, A., Coates-Estrada, R., Meritt, D.A., 1997. Anthropogenic landscape changes and avian diversity at Los Tuxtlas, Mexico. Biodivers. Conserv. 6, 19–43. Estrada, A., Anzures, A., Coates-Estrada, R., 1999. Tropical rain forest fragmentation, Howler Monkeys (Alouatta palliata) and dung beetles at Los Tuxtlas, Mexico. Am. J. Primatol. 48, 253–262. Favila, M.E., 2005. Diversidad alfa y beta de los escarabajos del estiércol (Scarabaeinae) en Los Tuxtlas, México. In: Halffter, G., Soberón, J., Koleff, P., Melic, A. (eds). Sobre diversidad biológica: el significado de las diversidades alfa, beta y gamma. Zaragoza: Monografías del Tercer Milenio. pp. 209–219. Favila, M.E., 2012. Historical, biogeographical and ecological factors explain the success of some native dung beetles after the introduction of cattle in Mexico. Pastos 42, 161–181. Filgueiras, B.K.C., Melo, D.H.A., Andersen, A.N., Tabarelli, M., Leal, I.R., 2019. Crosstaxon congruence in insect responses to fragmentation of Brazilian Atlantic forest. Ecol. Ind. 98, 523–530. Gardner, T.A., Hernández, M.I.M., Barlow, J., Peres, C.A., 2008. Understanding the biodiversity consequences of habitat change: the value of secondary and plantation forests for neotropical dung beetles. J. Appl. Ecol. 45, 883–893. Gasper, A.L., Eisenlohr, P.V., Salino, A., 2016. Improving collection efforts to avoid loss of biodiversity: lessons from comprehensive sampling of lycophytes and ferns in the subtropical Atlantic Forest. Acta Botanica Brasílica 30, 166–175. Génier, F., 2009. Le genre Eurysternus Dalman, 1824 (Scarabaeidae: Scarabaeinae : Oniticellini), révision taxonomique et clés de détermination illustrées. Pensoft: Moscow. González-Tokman, D., Martínez, I.M., Villalobos-Ávalos, Y., Munguía-Steyer, R., OrtizZayas, M.R., Cruz-Rosales, M., Lumaret, J., 2017. Ivermectin alters reproductive success, body condition and sexual trait expression in dung beetles. Chemosphere 178, 129–135. Guevara, S., Laborde, J., Sánchez, G., 2004. Los Tuxtlas. El paisaje de la sierra. Mexico DF: Instituto de Ecología. Guevara, S., Laborde-Dovalí, J., Sánchez-Ríos, G., 2000. La reserva de la Biosfera Los Tuxtlas. UNESCO, Paris. Gray, C.L., Hill, S.L.L., Newbold, T., Hudson, L.N., Börger, L., Contu, S., Hoskins, A.J., Ferrier, S., Purvis, A., Scharlemann, J.P.W., 2016. Local biodiversity is higher inside than outside terrestrial protected areas worldwide. Nat. Commun. 7, 1–17. Gullison, R.E., Hardner, J., 2018. Progress and challenges in consolidating the management of Amazonian protected areas and indigenous territories. Conserv. Biol. 32, 1020–1030. Gutiérrez-García, G., Ricker, M., 2011. Climate and climate change in the region of Los Tuxtlas (Veracruz, Mexico): A statistical analysis. Atmósfera 24, 347–373. Haddad, N.M., et al., 2015. Habitat fragmentation and its lasting impact on Earth’s ecosystems. Sci. Adv. 1, 1–9. Halffter, G., Favila, M.E., Halffter, V., 1992. A comparative study of the structure of the scarab guild in Mexican tropical rain forests and derived ecosystems. Folia Entomológica Mexicana 84, 131–156. Halffter, G., Favila, M.E., 1993. The Scarabaeinae (Insecta: Coleoptera) an animal group for analyzing, inventorying and monitoring biodiversity in tropical rainforest and modified landscapes. Biol. Int. 27, 15–21. Halffter, G., Edmonds, W.D., 1982. The Nesting Behavior of Dung Beetles. Mexico DF, Instituto de Ecología. Hallmann, C.A., Sorg, M., Jongejans, E., Siepel, H., Hofland, N., Schwan, H., Stenmans, W., Muller, A., Sumser, H., Horren, T., Goulson, D., Kroon, H., 2017. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS One 12, e0185809. Hanski, I., Cambefort, Y., 1991. Dung Beetle Ecology. Princeton, Princeton University

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements We thank A Díaz, F Caselín, F Armas and A Jacome for support during fieldwork. We acknowledge A Díaz for the identification of collected materials. We also thank A Córdoba-Aguilar and O RíosCárdenas for reviewing the project and making valuable suggestions. We thank the staff from Los Tuxtlas Biological Station (UNAM) for logistic support during fieldwork. We also thank CONACYT for a scholarship granted to RPS over the course of the study and project CONACYT Ciencia Básica No. 257894. ME Sánchez-Salazar edited the English manuscript. Appendix A. Supplementary data Supplementary data to this article can be found online at https:// doi.org/10.1016/j.ecolind.2019.105968. References Alvarado, F., Escobar, F., Williams, D.R., Arroyo-Rodríguez, V., Escobar-Hernández, F., 2017. The role of livestock intensification and landscape structure in maintaining tropical biodiversity. J. Appl. Ecol. 55, 185–194. Anderson, M.J., 2006. Distance based tests for homogeneity of multivariate dispersions. Biometrics 62, 245–253. Audino, L.D., Louzada, J., Comita, L., 2014. Dung beetles as indicators of tropical forest restoration success: Is it possible to recover species and functional diversity? Biol. Conserv. 169, 248–257. Ballesteros-Mejia, L., Lima, J.S., Collevatti, R.G., 2018. Spatially-explicit analyses reveal the distribution of genetic diversity and plant conservation status in Cerrado biome. Biodivers. Conserv. 2018. https://doi.org/10.1007/s10531-018-1588-9. Barlow, J., França, F., Gardner, T.A., Hicks, C.C., Lennox, G.D., Berenguer, E., Castello, L., Economo, E.P., Ferreira, J., Guénard, B., Leal, C.G., Isaac, V., Lees, A.C., Parr, C.L., Wilson, S.K., Young, P.J., Graham, N.A.J., 2018. The future of hyperdiverse tropical Ecosystems. Nature 559, 517–526. Baselga, A., Orme, D., Villeger, S., Bortoli, J.D., Leprieur, F., Logez, M., Henrique-Silva, R., 2018. Partitioning Beta Diversity into turnover and nestedness components. https://cran.r-project.org/web/packages/betapart/betapart.pdf assessed in 1st February 2019. Bennett, A.F., Saunders, D.A., 2010. Habitat fragmentation and landscape change. In: Sodhi, N.S., Ehrlich, P.R. (Eds.), Conservation Biology for All. Oxford University Press, Oxford, pp. 88–106. Borner, J., Baylis, K., Corbera, E., Ezzine-deBlas, D., Ferraro, P.J., Honey-Rosés, J., Lapeyre, R., Persson, U.M., Wunder, S.,, 2016. Emerging evidence on the effectiveness of tropical forest conservation. PLoS One 11, e0159152. Bourg, A., Escobar, F., MacGregor, I., Moreno, C.E., 2016. Got dung? Resource selection by dung beetles in Neotropical forest fragments and cattle pastures. Neotropical Entomol. 45, 490–498. Braga, R.F., Korasaki, V., Andresen, E., Louzada, J., 2013. Dung beetle community and functions along a habitat-disturbance gradient in the Amazon: a rapid assessment of ecological functions associated to biodiversity. PLoS One 8, e57786. Carpio, C., Donoso, D.A., Ramón, G., Dangles, O., 2009. Short term response of dung beetle communities to disturbance by road construction in the Ecuadorian Amazon. Annales de la Société entomologique de France 45, 455–469. Clarke, K.R., Gorley, R.N., 2006. Primer v6: user manual/tutorial. Primer-e: Plymouth. Chao, A., Lin, S.Y., 2011. Program CLAM (Classification Method). Program and user’s guide. http://purl.oclc.org/clam assessed in 20th October 2018. Chao, A., Jost, L., 2012. Coverage-based rarefaction and extrapolation: standardizing samples by completeness rather than size. Ecology 93, 2533–2547. Chao, A., Ma, K.H., Hsieh, T.C., 2016. User’s Guide for iNEXT Online: Software for Interpolation and Extrapolation of Species Diversity. http://140.114.36.3/wordpress/wp-content/uploads/software/iNEXTOnline_UserGuide.pdf assessed in 6th August 2019. Chazdon, R.L., Harvey, C.A., Komar, O., Griffith, D.M., Ferguson, B.G., Martínez-Ramos, M., Morales, H., Nigh, R., Soto-Pinto, L., Breugue, M.V., Philpott, S.M., 2009. Beyond

10

Ecological Indicators 111 (2020) 105968

R.P. Salomão, et al.

Raguso, R.A., Llorene-Bousquets, J., 1990. The butterflies (Lepidoptera) of the Tuxtlas Mts., Veracruz, Mexico, revisited: species-richness and habitat disturbance. J. Res. Lepidoptera 29, 105–133. Raine, E.H., Slade, E.M., 2019. Dung beetle–mammal associations: methods, research trends and future directions. Proceedings of the Royal Society B 286, 20182002. Rajakaruna, H., Drake, D.A.R., Chan, F.T., Bailey, S.A., 2016. Optimizing performance of nonparametric species richness estimators under constrained sampling. Ecol. Evol. 6, 7311–7322. Ranta, P., Blom, T., Niemela, J., Joensuu, E., Siitonen, M., 1998. The fragmented Atlantic rain forest of Brazil: size, shape and distribution of forest fragments. Biodivers. Conserv. 7, 385–403. Salomão, R.P., Brito, L.C., Iannuzzi, L., Lira, A.F.A., Albuquerque, C.M.R., 2019. Effects of environmental parameters on beetle assemblage in a fragmented tropical rainforest of South America. J. Insect Conserv. 23, 111–121. Sarges, R., Halffter, G., Díaz-Rojas, A., 2012. The importance of frugivory to the survival of the dung beetle Onthophagus rhinolophus Harold (Coleoptera: Scarabaeidae: Scarabaeinae) under changing ecological conditions. Coleopterists Bull. 66, 166–168. Sarkar, D., 2018. Package ‘lattice’. https://cran.r-project.org/web/packages/lattice/lattice.pdf assessed in 14th October 2019. Scholtz, A.D.L., Davis, A.L., Kryger, U., 2009. Evolutionary Biology and Conservation of Dung Beetles. Pensoft Publishers, Sofia. Scriven, S.A., Hodgson, J.A., McClean, C.J., Hill, J.K., 2015. Protected areas in Borneo may fail to conserve tropical forest biodiversity under climate change. Biol. Conserv. 184, 414–423. Silva, R.J., Coletti, F., Costa, D.A., Vaz-de-Mello, F.Z., 2014. Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) of forests and pastures of southwestern Brazilian Amazon: survey of species and feeding guilds. Acta Amazonica 44, 345–352. Signorell, A., 2018. DescTools: tools for descriptive statistics. https://cran.r-project.org/ web/packages/DescTools/index.html assessed in 20th October 2018. Simpson, G.L., R Core Development Team, Bates, D.M., Oksanen, J., 2018. Package ‘permute’. https://cran.r-project.org/web/packages/permute/permute.pdf assessed in 14th October 2019. Spector, S., 2006. Scarabaeine dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae): an invertebrate focal taxon for biodiversity research and conservation. Coleopterists Bull. 60, 71–83. von Thaden, J.J.V., Laborde, J., Guevara, S., Venegas-Barrera, C.S., 2018. Forest cover change in the Los Tuxtlas biosphere reserve and its future: the contribution of the 1998 protected natural area decree. Land Use Policy 72, 443–450. Vega-Vela, V., Muñoz-Robles, C.A., Rodríguez-Luna, E., López-Acosta, J.C., SernaLagunes, R., 2018. Analysis of landscape fragmentation in the Los Tuxtlas Biosphere Reserve, Veracruz, Mexico. Ecosistemas y Recursos Agropecuarios 5, 227–238. Verdú, J.R., Cortez, V., Ortiz, A.J., González-Rodríguez, E., Martinez-Pinna, J., Lumaret, J., Lobo, J., Numa, C., Sánchez-Piñero, F., 2015. Low doses of ivermectin cause sensory and locomotor disorders in dung beetles. Sci. Rep. 5, 13912. Villaseñor, J.L., Ortiz, E., Campos-Villanueva, A., 2018. High Richness of Vascular Plants in the Tropical Los Tuxtlas Region, Mexico. Trop. Conserv. Sci. 11, 1–12. Whittaker, R.J., 1975. Communities and Ecosystems. MacMillan Publishing Co, New York. Wuerthner, G., Crist, E., Butler, T., 2015. Protecting the Wild – Parks and Wilderness, The Foundation of Conservation. Foundation for Deep Ecology, San Francisco. Zuur, A.F., Ieno, E.N., Walker, N.J., Saveliev, A.A., Smith, G.M., 2009. Mixed Effects Models and Extensions in Ecology with R. Springer, New York.

Press. Hernández, M.I.M., Barreto, P.S.C.S., Costa, V.H., Creão-Duarte, A.J., Favila, M.E., 2014. Response of a dung beetle assemblage along a reforestation gradient in Restinga forest. J. Insect Conserv. 18, 539–546. Hill, M.O., 1973. Diversity and evenness: a unifying notation and its consequences. Ecology 54, 427–431. Ibiología, 2019. Aspectos bióticos de la región. http://www.ibiologia.unam.mx/tuxtlas/ localizacion/aspectos/centro.htm assessed in 3rd april 2019. Jost, L., 2006. Entropy and diversity. Oikos 113, 363–375. Kiffney, P.M., Clements, W.H., 1996. Size-dependent response of macroinvertebrates to metals in experimental streams. Environ. Toxicol. Chem. 15, 1352–1356. Klein, B.C., 1989. Effects of forest fragmentation on dung and carrion beetle communities in Central Amazonia. Ecology 70, 1715–1725. Kohlmann, B., Solís, A., 2001. El género Onthophagus (Coleoptera: Scareabaeidae) en Costa Rica. Giornale Italiano di Entomologia 9, 159–261. Larsen, T.H., Lopera, A., Forsyth, A., 2006. Extreme trophic and habitat specialization by Peruvian dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae). Coleopterists Bull. 60, 315–324. Laurance, W.F., et al., 2012. Averting biodiversity collapse in tropical forest protected areas. Nature 489, 290–294. Legendre, P., 2014. Interpreting the replacement and richness difference components of beta diversity. Glob. Ecol. Biogeogr. 23, 1324–1334. Marcon, E., Hérault, B., 2015. entropart: An R Package to Measure and Partition Diversity. J. Stat. Softw. 67, 1–26. Moctezuma, V., Halffter, G., 2017. A New species of Phanaeus Macleay (Coleoptera: Scarabaeidae:Scarabaeinae) from Los Chimalapas, Oaxaca, Mexico. Coleopterists Bull. 71, 47–56. Montes-de-Oca, T., Halffter, G., 1995. Daily and seasonal activities of a guild of the coprophagous, burrowing beetle (Coleoptera Scarabaeidae Scarabaeinae) in tropical grassland. Trop. Zool. 8, 159–180. Naturalista, 2019. Lista de especies de la Reserva de la Biosfera Los Tuxtlas, RB Los Tuxtlas, Veracruz. https://www.naturalista.mx/lists/110169-Lista-de-especies-de-laReserva-de-la-Biosfera-Los-Tuxtlas assessed in 3rd April 2019. Navarrete, D., Halffter, G., 2008. Dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) diversity in continuous forest, forest fragments and cattle pastures in a landscape of Chiapas, Mexico: the effects of anthropogenic changes. Biodiver. Conserv. 17, 2869–2898. Nichols, E., Larsen, T., Spector, S., Davis, A.L., Escobar, F., Favila, M., Vulinec, K., 2007. Global dung beetle response to tropical forest modification and fragmentation: A quantitative literature review and meta-analysis. Biol. Conserv. 137, 1–19. Nichols, E., Spector, S., Louzada, J., Larsen, T., Amezquita, S., Favila, M.E., 2008. Ecological functions and ecosystem services provided by Scarabaeinae dung beetles. Biol. Conserv. 141, 1461–1474. Nichols, E., Gardner, T.A., Peres, C.A., Spector, S., 2009. The scarabaeinae research network co-declining mammals and dung beetles: an impending ecological cascade. Oikos 118, 481–487. Oksanen, J., Blanchet, F.G., Kindt, R., Legendre, P., Minchin, P.R., O’Hara, R.B., … Wagner, H., 2016. vegan: community ecology package. https://CRAN.R-project.org/ package=vegan assessed in 5th October 2018. Quintero, I., Roslin, T., 2005. Rapid recovery of dung beetle communities following habitat fragmentation in Central Amazonia. Ecology 86, 3303–3311. R Core Development Team, 2015. R: A language and environment for statistical computing. R foundation for statistical computing: Vienna.

11