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1 May 2013 The Role of Small Woodland Remnants on Ground Dwelling Insect Conservation in Chaco Serrano, Central Argentina
María Laura Moreno, María Guadalupe Fernández, Silvia Itati Molina, Graciela Valladares
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Abstract

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint.

Introduction

Habitat fragmentation, i.e., the transformation of an originally large habitat into smaller and isolated remnants embedded in a matrix with different land use, has been recognized as a major threat to biodiversity (Fahrig 2003). Remnant area and isolation are expected to affect population abundance and diversity (Ewers and Didham 2006). According to the island biogeography theory (MacArthur and Wilson 1967), smaller and more isolated remnants should sustain fewer species than larger and less isolated sites, as a consequence of lower immigration and higher local extinction rates (Fujita et al. 2008). Also, metapopulation theory (Hanski and Gilpin 1991) predicts that populations in habitat patches periodically go extinct and are recolonized by individuals migrating from other remnants across the matrix (Davies et al. 2001), therefore increasing isolation should result in reduced probability of colonization. Another important feature of fragmented habitats is the difference in abiotic conditions, including temperature, humidity, light, and wind speed, at the edge of remnants in comparison with their interior (Saunders et al. 1991; Murcia 1995; Laurance et al. 2007). These conditions could strongly affect small and ectothermic animals such as insects (Grimbacher et al. 2006). Moreover, conditions at the edge habitat could selectively impair survival of some species while facilitating invasion by opportunist/generalist species from the matrix (Laurance et al. 2002; Tscharntke et al. 2002a; Ewers and Didham 2006), thus resulting in higher diversity and altered composition.

Insects represent the major group in terms of terrestrial biodiversity, accounting for over 75% of all known animal species (Speight et al. 2008). Because of their diversity, abundance, easy sampling, and rapid response to environmental changes, insects are useful bio-indicators of habitat degradation (Bolger et al. 2000; Cagnolo et al. 2002) and have therefore been widely used to study the effects of habitat fragmentation (Debinsky and Holt 2000; Hunter 2002; Grimbacher et al. 2008). In particular, the study of epigaeic or ground dwelling insects has important functional implications because of the insects varied ecological roles, as they include predators, scavengers, and herbivores (Didham 1996).

Heterogeneous responses to remnant size have been reported for ground insect species in fragmented woodlands, ranging from positive (Didham et al. 1998; Fujita et al. 2008) to negative relationships (Davies et al. 2001; Yaacobi et al. 2007) between abundance, richness or diversity, and remnant area. Also, contrasting responses have been found for edge (Grimbacher et al. 2006; Sobrinho and Schoereder 2006) and isolation effects (Yaacobi et al. 2007). However, little is known about habitat fragmentation effects at higher taxonomic levels such as family (Grimbacher et al. 2008), which have proved useful to evaluate insect responses in disturbed habitats (Basset et al. 2004). Family taxonomic level is fairly often used in analyses of perturbation effects on ground dwelling insects, with limitations for inferences regarding within-family variability (correlation with environmental conditions may be masked by the differential responses of different species from the same family) being compensated by the possibility of assessing broader community trends (e.g., Zilihona and Nummelin 2001; Yu et al. 2006; Bennet and Gratton 2012).

The functional diversity of epigaeic insects allows for the consideration of feeding guilds as a complementary analysis to that of taxonomic diversity. The analysis of feeding guilds focuses on “what organisms do” by grouping together species that exploit the same resources in the same way (Blaum et al. 2011). This approach is critical for understanding the potential consequences of biodiversity for ecosystem processes, and helps generalization of the results in comparison with taxonomically centered studies (Blaum et al. 2011). Not all feeding guilds are expected to be affected by habitat fragmentation in the same way. The trophic rank hypothesis (Zabel and Tscharntke 1998; Holt et al. 1999) predicts that species at higher trophic levels, like predators, are more vulnerable to extinction following a perturbation, such as habitat fragmentation. In turn, changes at higher trophic levels could trigger further community changes that might affect the system dynamics. However, few studies have considered the effects of subtropical forest fragmentation on ground dwelling insects in terms of feeding guilds (e.g., Lange et al. 2011), since research has usually been focused on restricted groups of species, mostly within Coleoptera (Davies et al. 2001; Grimbacher et al. 2008).

In central Argentina, human activities have led to a 94% reduction of the Chaco Serrano woodland, a district within the extensive South American Chaco forest, resulting in isolated patches within a predominantly agricultural matrix (Zak and Cabido 2004). In this system, habitat fragmentation has been shown to affect plant diversity and reproduction (Aguilar and Galetto 2004; Cagnolo et al. 2006; Galetto et al. 2007), herbivory and parasitism rates (Valladares et al. 2006), species richness of insect herbivores and parasitoids (Cagnolo et al. 2009), and even food web structure (Valladares et al. 2011). In our study, the communities of ground dwelling insects associated to remnants of Chaco Serrano are examined in a fragmented landscape.

Whether abundance, diversity, and taxonomic composition of ground dwelling insect families are related to remnant area, isolation, or within-remnant location (edge/interior) is examined. Furthermore, a functional approach is included, by partitioning the studied communities in feeding guilds, in order to consider the possibility of differential risk from habitat fragmentation in relation to particular ecological processes. In particular, abundance, richness, and diversity of ground dwelling insect families were expected to be positively related with remnant area and negatively with isolation. Also, there were expected to be more abundant and diverse insect assemblages at the edge of remnants in comparison with their interior. Finally, predators were expected to be most sensitive to habitat fragmentation.

Methods

Study area

This study was conducted within the Chaco Serrano District, in Central Argentina (Luti et al. 1979). The average annual rainfall in the region is about 750 mm, concentrated in the warm season (October–April), with maximum and minimum temperatures of 26° C and 10° C, respectively (Luti et al. 1979; Moglia and Jiménez 1998). The characteristic vegetation is a low, open woodland, with a tree layer (8– 15 m high) dominated by Aspidosperma quebracho-blanco Schltdl., Prosopis spp., Zanthoxylum coco Gillies ex Hook. f. and Arn., and Lithrea molleoides (Vell.) Engl.; shrubs (1.5–3 m), such as Celtis pallida Torr. and Acacia spp.; herbs and grasses (0–1 m), and many vines and epiphytic bromeliads (Cabido et al. 1991). At present, this vegetation is reduced to isolated remnants (Zak et al. 2004) embedded in a predominantly agricultural matrix.

Nine remnants, ranging in size from 0.57 hectares to over 1000 hectares, were selected (Figure 1) within an area located between 31° 10′ and 31° 30′ S and 64° 00′ and 64° 30′ W, with an elevation of 500 to 600 m. The degree of isolation was estimated by the nearest neighbor method (Krebs 1999). All remnants had been isolated for at least 30 years in a matrix dominated by wheat in winter and soybean or maize in summer.

Sampling procedures

The insects were captured using pit-fall traps (10 cm diameter, 15 cm deep) containing a 20% solution of ethylene glycol. The traps were exposed 5 to 7 days at each of two sampling dates, December 2003 and March 2004. At each remnant, three traps were placed 5 m apart from each other and within 5 m of the tree line indicating the boundary of the forest (edge location), and three more traps were placed in a row parallel to the former but at least 20 m from the forest border (interior location). All insects collected were counted and identified to family level. The following variables were calculated: abundance (number of individuals), richness (number of insect families), and diversity (Shannon-Weaver index). This index was calculated as: H' = -Σpi.lnpi, where pi is the proportion of individuals found in the ith families (Magurran 2004). Because Shannon entropies index gives the uncertainty rather than diversity, Shannon values were converted to effective number of species (e(H')) (Jost 2006). The following feeding guilds were considered for functional analysis: scavengers, herbivores, and predators. When more than one guild was represented within a family, the predominant habit was considered (Borror et al. 1997).

Data analysis

The degree of similarity in the taxonomic composition of ground insect communities associated to the various remnants was explored by performing a correspondence analysis and subsequent correlation analyses on insect family abundance data. Spearman correlations were employed between community position for the first two correspondence analysis axes, and remnant area or isolation, in order to assess the importance of habitat fragmentation variables on community taxonomic arrangement. A Mantel Test was performed to provide further insight into spatial effects on insect community composition by considering whether communities most closely resemble those in nearer remnants. The Mantel Test examines the null hypothesis of non-concordance between two distance matrices (Legendre and Legendre 1998). The Bray-Curtis distance matrix based on insect family abundance data was compared to a matrix based on geographical distance (km) between sampling sites, using the Mantel's asymptotic approximation for statistical significance.

To analyze possible effects of habitat fragmentation on the insect communities, a linear mixed model was performed (Pinheiro and Bates 2000), with abundance (NT), richness (S), or diversity of insect families as response variables, location (edge/interior), remnant area, and isolation as fixed effects, and site (remnant) as random effect. Interactions between fixed effects were evaluated. Non-significant interactions were removed in order to obtain the most parsimonious model. The statistical analyses were performed using the software R 2.11.0 (R Development Core Team 2010).

The effects of remnant area on the different feeding guilds were compared by means of analysis of covariance (ANCOVA) considering abundance and richness of each feeding guild as response variables, feeding guild as the fixed effect, and remnant area as the covariable. A significant interaction with remnant area would indicate different slopes and thus differential area effects for the groups considered (Zar 1996).

Table 1.

Results of linear mixed models examining the relationship between edge/interior localization, remnant area and isolation vs. abundance, richness, and diversity of ground-dwelling family insects in nine Chaco Serrano remnants.

t01_01.gif

Statistical analyses were based on the average number of individuals per trap per capture day. After checking data distribution, values were log x+1 (insect abundance) or log transformed (family richness and remnant size) in order to achieve normal distribution. Ants (Hymenoptera: Formicidae) were analyzed separately because of their extremely high abundance coupled with social and gregarious behavior.

Results

Taxonomic composition

In total, 7071 insects representing 12 orders and 79 families were collected (see Appendix).

Slightly over half of the variation in taxonomic composition of the studied insect communities was explained in the correspondence analysis, with the first axis accounting for 29.78% and the second axis 24.92% of that variation (Figure 2). Only the first correspondence analysis axis was strongly negatively correlated with remnant area (r = -0.83, p = 0.02), whereas no axes were correlated with isolation. Staphilinidae, Nitidulidae, Eucinetidae, Carabidae, Cydnidae, and Lampyridae were the families with stronger positive association to the first axis, i.e., to smaller remnants, whereas Hymenoptera parasitica, Thysanoptera, Phoridae, and Histeridae were closely associated to larger remnants

Moreover, the Mantel Test showed no significant compositional turnover with geographic distance (r = -0.31, p = 0.29).

Abundance, richness, and diversity of insect families

Abundance and richness of insect families decreased as remnant area increased, although results for the latter variable were only marginally significant (Table 1, Figure 3). Community diversity (Table 1) and ant abundance (Table 1) were independent of remnant area. Moreover, there were no effects of isolation or edge/interior location on insect abundance, richness, or diversity (Table 1).

Functional composition

Regarding functional composition (Figure 4) of the ground dwelling communities, scavengers were the most abundant (49 ± 2% of collected insects) and diverse (36% of families) feeding guild, followed by herbivores (28 ± 2.38% individuals, 32% families) and predators (22 ± 1.14% individuals, 20% families).

Table 2.

Results from analysis of covariance testing for differential relationships in abundance and richness of three feeding guilds (predators, herbivores, scavengers) vs. remnant area in Chaco Serrano.

t02_01.gif

Feeding guild significantly influenced insect abundance and richness, but did not show differential relationships with area (Table 2).

Discussion

According to the results of our study, differences in abundance and taxonomic composition of ground dwelling insect communities were linked to forest area, with no obvious edge or isolation effects.

Which insect families were present in a particular forest remnant seemed to be at least partly determined by the size of the remnant. Different factors could be operating at different spatial scales, as observed for other ground dwelling insect communities (e.g., Barton et al. 2009) and could be related to environmental heterogeneity or to insect traits such as dispersal ability, body size, and food requirements.

Contrary to expectations from island biogeography theory and metapopulation theory, ground dwelling insects in this fragmented Chaco Serrano landscape were more abundant and, albeit marginally, richer in smaller remnants. Negative relationships between abundance and habitat area have also been reported in other studies on epigaeic insects (e.g., Davies et al. 1998; Grez et al. 2004; Henríquez et al. 2009). Such trends could reflect colonization by habitat generalists arriving from or through the matrix, as small remnants would be the most likely place for habitat generalists to invade (Halme and Niembelä 1993). In other cases, similar patterns of abundance/richness have been shown to be related to resource availability in systems where small remnants showed higher habitat heterogeneity or plant diversity (Tscharntke et al. 2002b; Jonsson et al. 2009). However, previous studies have found lower plant richness in smaller Chaco Serrano remnants (Cagnolo et al. 2006). Since capture in pitfall traps depends on insect mobility (Perner and Schueler 2004), higher abundance could also result from easier movements in a less restrictive environment, e.g., if ground level vegetation structures were simpler in smaller remnants.

Communities at remnant edges did not differ from those found deeper in the forest, either in terms of abundance, richness, or diversity of epigaeic insect families. It is possible that inputs from the matrix may have numerically compensated for the absence of some interior specific insects at the edge. For example, in a forest-clearcut ecotone in China, abundance, richness, and diversity of ground dwelling beetle families were similar in forest interior and edge, despite the edge hosting insects from both the forest and the clearcut matrix (Yu et al. 2006). Obviously, patterns observed at family taxonomic level may mask species-specific responses to environmental conditions. In this sense, various studies have shown species-specific and trait-related responses to the interior/edge situation (Didham et al. 1998; Davies et al. 2001; Lövei et al. 2006), which might be overlooked when considering general community trends. Moreover, edge-related microclimatic changes in some systems can penetrate more than 30 m into the interior (Laurance et al. 2002), thus the distance between edge and interior in samples from our study (20 m) might be deemed insufficient to detect edge effects. Nonetheless, in a previous study, the same distance was enough to show edge-related differences in herbivory and parasitism rates in Chaco Serrano remnants (Valladares et al. 2006).

The consequences of habitat fragmentation effects on particular functional groups or feeding guilds could be important because of their possible impact on ecosystem functioning. However, in coincidence with other studies on ground dwelling insects (Yu et al. 2006; Grimbacher et al. 2008), no differential relationship was found in our study between feeding guilds and habitat fragmentation. Contrary to expectations, predators did not appear to be more sensitive to habitat loss than herbivore or scavengers insects, therefore the results did not support the trophic position hypothesis (Kruess and Tscharntke 2000; Holt 2002). Despite the variations in abundance and species number reported above, communities of ground dwelling insects along a gradient of remnant sizes appear thus to be similar in terms of the ecosystem functions they perform.

In summary, by applying a multilevel approach (Thornton et al. 2011) simultaneously considering within-patch (edge effects), focal patch (area), and landscape level (isolation) variables, it was found that ground insect communities in fragmented Chaco Serrano respond mainly to the patch level by increasing their abundance (and, in a lesser degree, their richness) in smaller remnants. The lack of isolation or edge effects in this study corroborates the importance of area as the main factor affecting biodiversity in fragmented systems (Fahrig 2003). These results suggest small Chaco Serrano remnants may play an important role from a conservation viewpoint by supporting larger ground dwelling insect assemblages, and preserving remnants of various sizes would be favorable for insect conservation in this subtropical forest.

Figure 1.

Location of study remnants (in black) in Chaco Serrano forest, Central Argentina. High quality figures are available online.

f01_01.jpg

Figure 2.

Correspondence analysis of ground dwelling insect communities from nine remnants of Chaco Serrano. Squares represent forest remnants, triangles represent insect families. Figures next to each square indicate remnant size (in hectares). Only families with the strongest association with the first axis are named. High quality figures are available online.

f02_01.jpg

Figure 3.

Relationship between abundance (a), richness (b), and diversity (c) of ground dwelling insects vs. remnant area in Chaco Serrano. Regression lines based on linear mixed models (see Table 1). Open symbols = interior, filled symbols = edge. High quality figures are available online.

f03_01.jpg

Figure 4.

Relative representation of ground dwelling insect feeding guilds in nine remnants of Chaco Serrano. High quality figures are available online.

f04_01.jpg

Acknowledgements

We thank M. Zak and L. Galetto for helping in site selection, S. Fenoglio and M. Videla for comments on an earlier version of the manuscript, landowners (Estancia Santo Domingo) for giving us access to forest remnants and two anonymous referees for their helpful comments. This research was supported by FONCYT, CONICET, and SECYT-UNC. G. Valladares is a research member of and M. L. Moreno is a grant student of Consejo Nacional de Investigaciones Científicas y Técnicas.

References

1.

R Aguilar , L Galetto . 2004. Effects of forest fragmentation on male and female reproductive success in Cestrum parqui (Solanaceae). Oecologia 138: 513–520. Google Scholar

2.

PS Barton , AD Manning , H Gibb , DB Lindenmayer , SA Cunningham . 2009. Conserving ground-dwelling beetles in an endangered woodland community: Multi-scale habitat effects on assemblage diversity. Biological Conservation 142: 1701–1709. Google Scholar

3.

Y Basset , JF Mavoungou , JB Mikissa , O Missa , SE Miller , RL Kitching . 2004 Discriminatory power of different arthropod data sets for the biological monitoring of anthropogenic disturbance in tropical forests. Biodiversity and Conservation 13: 709–732. Google Scholar

4.

N Blaum , E Mosner , M Schwager , F Jeltsch . 2011. How functional is functional? Ecological grouping in terrestrial animal ecology: towards an animal functional type approach. Biodiversity and Conservation 20: 233–234. Google Scholar

5.

AB Bennett , C Gatton . 2012. Local and landscape scale variables impact parasitoid assemblages across an urbanization gradient. Landscape and Urban Planning 104: 26–33. Google Scholar

6.

DT Bolger , AV Suarez , KR Crooks , SA Morrison , TJ Case . 2000. Arthropods in urban habitat fragments in southern California: area, age and edge effects. Ecological Applications 10: 1230–1248. Google Scholar

7.

DJ Borror , CA Triplehorn , NF Johnson . 1997. An Introduction to the Study of Insects , 7th edition. Saunders College Publishing. Google Scholar

8.

M Cabido , ML Carranza , A Acosta , S Páez . 1991. Contribución al conocimiento fitosociológico del Bosque Chaqueño Serrano en la provincia de Córdoba, Argentina. Phytocoenología 19: 547–566. Google Scholar

9.

L Cagnolo , SI Molina , GR Valladares . 2002. Diversity and guild structure of insect assemblages under grazing and exclusion regimes in a montane grassland from Central Argentina. Biodiversity and Conservation 11: 407–420. Google Scholar

10.

L Cagnolo , M Cabido , GR Valladares . 2006. Plant species richness in the Chaco Serrano Woodland from central Argentina: Ecological traits and habitat fragmentation effects. Biological Conservation 132: 510–519. Google Scholar

11.

L Cagnolo , G Valladares , A Salvo , M Cabido , M Zak . 2009. Habitat fragmentation and species loss across three interacting trophic levels: effects of life-history and food-web traits. Conservation Biology 23: 1167–1175. Google Scholar

12.

KF Davies , CR Margules . 1998. Effects of habitat fragmentation on carabid beetles: experimental evidence. Journal of Animal Ecology 67: 460–471. Google Scholar

13.

KF Davies , BA Melbourne , CR Margules . 2001. Effects of within- and between- patch processes on community dynamics in a fragmentation experiment. Ecology 82: 1830–1846. Google Scholar

14.

DM Debinski , RD Holt . 2000. A survey and overview of habitat fragmentation experiments. Conservation Biology 14: 342–355. Google Scholar

15.

RK Didham , J Ghazoul , NE Stork , AJ Davies . 1996. Insects: a functional approach. Trends in Ecology & Evolution 11: 255–260. Google Scholar

16.

RK Didham , P Hammond , JH Lawton , P Eggleton , NE Stork . 1998. Beetle Species Responses to Tropical Forest Fragmentation. Ecological Monographs 68: 295–323. Google Scholar

17.

RM Ewers , RK Didham . 2006. Confounding factors in the detection of species responses to habitat fragmentation. Biological Review 81: 117–142. Google Scholar

18.

L Fahrig . 2003. Effects of habitat fragmentation on biodiversity. Annual Review of Ecology, Evolution and Systematics 34: 487– 515. Google Scholar

19.

A Fujita , K Maeto , Y Kagawa , N Ito . 2008. Effects of forest fragmentation on species richness and composition of ground beetles (Coleoptera: Carabidae and Brachinidae) in urban landscapes. Entomological Science 11 : 39–48. Google Scholar

20.

L Galetto , R Aguilar , M Musicante , J Astegiano , A Ferreras , M Jausoro , C Torres . 2007. Fragmentación de hábitat, riqueza de polinizadores, polinización y reproducción de plantas nativas en el Bosque Chaqueño de Córdoba, Argentina. Ecología Austral 17: 67– 80. Google Scholar

21.

AA Grez , T Zaviezo , S Reyes . 2004. Short-term effects of habitat fragmentation on the abundance and species richness of beetles in experimental alfalfa microlandscapes. Revista Chilena de Historia Natural 77: 547–558. Google Scholar

22.

PS Grimbacher , CP Catterall , RL Kitching . 2006. Beetle species responses suggest that microclimate mediates fragmentation effects in tropical Australian rainforest. Austral Ecology 31: 458–470. Google Scholar

23.

PS Grimbacher , CP Catterall , RL Kitching . 2008. Detecting the effects of environmental change above the species level with beetles in a fragmented tropical rainforest landscape. Ecological Entomology 33: 66–79. Google Scholar

24.

I Hanski , M Gilpin . 1991. Metapopulation dynamics: brief history and conceptual domain. Biological Journal of the Linnean Society 42: 3–16. Google Scholar

25.

E Halme , J Niembelä . 1993. Carabid beetles in fragments of coniferous forest. Annales Zoologica Fennici 30: 17–30. Google Scholar

26.

P Henríquez , DS Donoso , AA Grez . 2009. Populations density, sex ratio, body size and fluctuating asymmetry of Ceroglossus chilensis (Carabidae) in fragmented Maulino forest and sourrounding pine plantations. Acta Oecologica 35: 811–818. Google Scholar

27.

RD Holt , JH Lawton , GA Polis , ND Martinez . 1999. Trophic rank and the species area relationship. Ecology 80: 1495–1504. Google Scholar

28.

RD Holt . 2002. Food webs in space: On the interplay of dynamic instability and spatial processes. Ecological Research 17: 261–273. Google Scholar

29.

MD Hunter . 2002. Landscape structure, habitat fragmentation, and the ecology of insects. Agricultural and Forest Entomology 4: 159–166. Google Scholar

30.

M Jonsson , GW Yeates , DA Wardle . 2009. Patterns of invertebrate density and taxonomic richness across gradients of area, isolation, and vegetation diversity in a lake-island system. Ecography 32: 963–972. Google Scholar

31.

CJ Krebs . 1999. Ecological methodology , 2nd edition. Benjamin Cummings. Google Scholar

32.

L Jost . 2006. Entropy and diversity. Oikos : 113: 363–375. Google Scholar

33.

A Kruess , T Tscharntke . 2000. Species richness and parasitism in a fragmented landscape: experiments and field studies with insects on Vicia sepium. Oecologia 122: 129– 137. Google Scholar

34.

M Lange , WW Weisser , MM Gossner , E Kowalski , M Türke , F Joner , CR Fonseca . 2011. The impact of forest management on litter-dwelling invertebrates: a subtropical-temperate contrast. Biodiversity and Conservation 20: 2133–2147. Google Scholar

35.

WF Laurance , TE Lovejoy , HL Vasconcelos , EM Bruna , RK Didham , PC Stouffer , C Gascon , RO Bierregaard , SG Laurance , E Sampaio . 2002. Ecosystem decay of Amazonian forest fragments: a 22-year investigation. Conservation Biology 16: 605–618. Google Scholar

36.

WF Laurance , HEM Nascimento , SG Laurance , A Andrade , RM Ewers , KE Harms , RCC Luizão . 2007. Habitat fragmentation, variable edge effects, and the landscape-divergence hypothesis. PloS One 10: 1–8. Available online:  http://www.plosone.org  Google Scholar

37.

P Legendre , L Legendre . 1998. Numerical Ecology , 2nd English edition. Elsevier Science BV. Google Scholar

38.

GL Lövei , T Magura , B Tóthmérész , V Ködöböcz . 2006. The influence of matrix and edges on species richness patterns of ground beetles (Coleoptera: Carabidae) in habitat islands. Global Ecology and Biogeography 15: 283–289. Google Scholar

39.

R Luti , MA Bertran , FM Galera , N Mullier , M Berzal , M Nores , MA Herrera , JC Barrera . 1979. In: JC Vázquez , R Miatello , M Roqué , Editors. Geografía Física de la Provincia de Córdoba. pp. 297–368. Editorial Boldt. Google Scholar

40.

RH MacArthur , EO Wilson . 1967. The Theory of Island Biogeography. Princeton University Press. Google Scholar

41.

AE Magurran . 2004. Measuring biological diversity. Blackwell Publishing. Google Scholar

42.

G Moglia , AM Gimenéz . 1998. Rasgos anatómicos característicos del hidrosistema de las principales especies arbóreas de la región chaqueña argentina. Investigación Agraria: Sistemas y Recursos Forestales 7: 753–771. Google Scholar

43.

C Murcia . 1995. Edge effects in fragmented forests: implications for conservation. Trends in Ecology & Evolution 10: 58–62. Google Scholar

44.

J Pinheiro , D Bates . 2000. Mixed Effects Models in S and S-Plus. Springer Verlag. Google Scholar

45.

J Perner , S Schueler . 2004. Estimating the density of ground-dwelling arthropods with pitfall traps using a nested-cross array. Journal of Animal Ecology 73: 469–477. Google Scholar

46.

D Saunders , R Hobbs , C Margules . 1991. Biological Consequences of Ecosystem Fragmentation: A Review. Conservation Biology 5: 18–32. Google Scholar

47.

TG Sobrinho , JH Schoereder . 2006. Edge and shape effects on ant (Hymenoptera: Formicidae) species richness and composition in forest fragments. Biodiversity and Conservation 16: 1459–1470. Google Scholar

48.

MR Speight , M Hunter , AD Watt . 2008. Ecology of insects: concepts and applications , 2nd edition. Wiley-Blackwell. Google Scholar

49.

DH Thornton , LC Branch , ME Sunquist . 2011. The influence of landscape, patch, and within-patch factors on species presence and abundance: a review of focal patch studies. Landscape Ecology 26: 7–18. Google Scholar

50.

T Tscharntke , I Steffan-Dewenter , A Kruess , C Thies . 2002b. Characteristics of insect populations on habitat fragments: a mini review. Ecological Research 17: 229–239. Google Scholar

51.

T Tscharntke , I Steffan-Dewenter , A Kruess , C Thies . 2002b. Contribution of small habitat fragments to conservation of insect communities of grassland-cropland landscapes. Ecological Applications 12: 354–363. Google Scholar

52.

G Valladares , A Salvo , L Cagnolo . 2006. Habitat fragmentation effects on trophic processes of insect-plant food webs. Conservation Biology 20: 212–217. Google Scholar

53.

G Valladares , L Cagnolo , A Salvo . 2011. Forest fragmentation leads to food web contraction. Oikos 121: 299–305. Google Scholar

54.

G Yaacobi , Y Ziv , ML Rosenzweig . 2007. Effects of interactive scale-dependent variables on beetle diversity patterns in a semiarid-arid agricultural landscape. Landscape Ecology 22: 687–703. Google Scholar

55.

X-D Yu , T-H Luo , J Yang , H-Z Zhou . 2006. Distribution of ground-dwelling beetles (Coleoptera) across a forest-clearcut ecotone in Wolong Natural Reserve, southwestern China. Insect Science 13: 127–135. Google Scholar

56.

J Zabel , T Tscharntke . 1998. Does fragmentation of Urtica habitat affect phytophagous and predatory insect differentially? Oecologia 116: 419–425. Google Scholar

57.

M Zak , M Cabido . 2004. Do subtropical seasonal forests in the Gran Chaco, Argentina have a future? Biological Conservation 120: 589–598. Google Scholar

58.

JH Zar . 1996. Biostatistical analysis , 3rd edition. Prentice Hall. Google Scholar

59.

IJE Zilihona , M Nummelin . 2001. Coleopteran diversity and abundance in different habitats near Kihansi waterfall, in the Udzungwa Mountains, Tanzania. Biodiversity and Conservation 10: 769–777. Google Scholar

Appendices

Appendix.

Appendix.

Total abundance of insects families captured in nine remnants of Chaco Serrano between December 2003 and March 2004 in Chaco Serrano woodland. T.G. indicates taxonomic group (S = scavengers, H = herbivores, P = predators), and X indicates presence of insect in edge/interior localization.

tA01_01.gif
This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.
María Laura Moreno, María Guadalupe Fernández, Silvia Itati Molina, and Graciela Valladares "The Role of Small Woodland Remnants on Ground Dwelling Insect Conservation in Chaco Serrano, Central Argentina," Journal of Insect Science 13(40), 1-13, (1 May 2013). https://doi.org/10.1673/031.013.4001
Received: 29 December 2011; Accepted: 1 August 2012; Published: 1 May 2013
KEYWORDS
epigaeic insects
feeding guilds
habitat fragmentation
Subtropical forest
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