Microhabitats and Fragmentation Effects on a Ground Beetle Community (Coleoptera: Carabidae) in a Mountainous Beech Forest Landscape
Total Page:16
File Type:pdf, Size:1020Kb
Turkish Journal of Zoology Turk J Zool (2016) 40: 402-410 http://journals.tubitak.gov.tr/zoology/ © TÜBİTAK Research Article doi:10.3906/zoo-1404-13 Microhabitats and fragmentation effects on a ground beetle community (Coleoptera: Carabidae) in a mountainous beech forest landscape 1,2, 1,2 1 Slavčo HRISTOVSKI *, Aleksandra CVETKOVSKA-GJORGIEVSKA , Trajče MITEV 1 Institute of Biology, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje, Macedonia 2 Macedonian Ecological Society, Skopje, Macedonia Received: 10.04.2014 Accepted/Published Online: 12.08.2015 Final Version: 07.04.2016 Abstract: The aim of this investigation was to analyze the effects of microhabitats and forest fragmentation on the composition and species abundance of a ground beetle community from three different beech forest patches on Mt. Osogovo (Macedonia), as well as to analyze the mobility (based on mark-recapture of individuals) and seasonal dynamics and sex ratio of the ground beetle community. The study site included three localities (A, B, C), one of them fragmented (A), with four microhabitats (open area, ecotone, forest stand, and forested corridor). Ground beetles were collected using pitfall traps during four sampling months (June–September 2009) that were operational for three continuous days per month. Species richness, abundance, diversity, homogeneity, and dominance were compared between the localities. Dissimilarities in carabid assemblages between localities and microhabitats were analyzed with Bray–Curtis UPGMA cluster analysis. In total 1320 carabid individuals belonging to 19 species were captured. The carabid assemblage structure of the continuous forest locality was substantially different from the other two smaller forest patches, indicating that microhabitat structure affects ground beetle communities through changes of species composition and richness. Key words: Ground beetles, microhabitats, habitat fragmentation, beech forest, mountain landscape 1. Introduction This investigation aims at analyzing the composition Habitat fragmentation is one of the most important causes and species abundance of a ground beetle community of species decline and extinction throughout the world between different beech forest localities and microhabitats (Saunders et al., 1991; Haila et al., 1994; Didham et al., (forested part, ecotone, open space, and forested 1996; Didham, 1997; Davies et al., 2000). In the case of corridor), on Mt. Osogovo, as well as to analyze the effect forests the fragmentation impacts the size of forest patches, of fragmentation on the ground beetle community, the increases edge and isolation effects, and contributes to seasonal dynamics, the sex ratio, and the mobility (based overall habitat diversity in the place of a single continuous on mark-recapture of individuals). The collection of the forest (Abildsnes and Tømmeros, 2000; Fahrig, 2003). material was done by pitfall trapping without use of a Such habitat changes are suspected to impact biodiversity, preservative during one season (June–September 2009). but this impact varies greatly between taxonomic groups. For appropriate evaluation of the effects of microhabitats, Ground beetles are often used to assess the impact of habitat which undoubtedly lead to changes in the community changes because of their sensitivity to environmental structure of ground beetles, a complete qualitative- conditions (Thiele, 1977) and rapid responses to habitat quantitative analysis of the carabidocoenosis from the changes (Niemelä et al., 1993a, 1993b). forest interior, forested corridor, open space, and ecotone Forestry practices, meaning clear-cutting of large part was necessary. For this purpose analyses such as forest areas and subsequent planting, have turned the nonparametric Kruskal–Wallis tests followed by Mann– forest of Mt. Osogovo (in the northwest of the Republic Whitney tests and Spearman rank correlation coefficient of Macedonia) into a fragmented area with many small and Bray–Curtis (UPGMA) cluster analyses, as well as a isolated forest patches. The remaining young beech rarefaction method, were used. We also used indices of forest is mostly present as small, isolated fragments or richness – d, evenness – J , dominance – D, and Shannon– as unproductive areas. So far, the diversity of the ground (e) Wiener diversity – H’ in order to supplement the evidence beetle fauna of Osogovo Mountain was only documented of the differences between microhabitats and localities. by Guéorguiev (1996, 1997, 1998). * Correspondence: [email protected] 402 HRISTOVSKI et al. / Turk J Zool 2. Materials and methods In locality B there were also two transect lines. 2.1. Study area and sampling Transect T3 contained 21 pitfall traps and T4 contained 23 The experiment was carried out in a beech forest of the pitfall traps. All of the traps in T3 and T4 were placed in a Jamiško Osoe locality, at an altitude of about 1300 m. The forested part. forest association is Calamintho grandiflorae-Fagetum Em, Locality C consisted of three transect lines (T5 with 1948. The area falls within the mountain broadleaf forest 12, T6 with 14, and T7 with 16 pitfall traps). Transect T5 landscape (Melovski, personal communication). contained 12 traps (traps 1–6 in the forested part, 7 in the The study site was divided into three localities, A, B, and ecotone, and 8–12 in the open space (grassland)). Transect C: A contains a forested fragment, B is an unfragmented T6 contained 14 traps (traps 1–12 in the forested part, 13 continuous forest, and C is a forested peninsula (Figure and 14 in the forested peninsula). Transect T7 contained 1), with four microhabitats identified within them. A and 16 traps (traps 1–5 in the forested part, 6–9 in the ecotone, B include three microhabitats (open space, ecotone, and and 10–15 in the open space). forest), while C includes four microhabitats (open space, The traps and the transect lines were placed at 5 m ecotone, forest, and corridor). and at least 10 m apart, respectively. Traps were without Beetles were collected using pitfall traps that consisted preservatives and placed flush with the soil surface. To of plastic cups with volume of 500 mL, diameter of 8.5 cm, prevent flooding from the rain during the noninvestigated and height of 11.5 cm. In total, 150 traps were placed in period, plastic roofs were mounted above each trap. all of the seven transects (Figure 1). The number of traps Ground beetles were collected, captured, registered, and along transects was different and varied from 12 to 32. immediately released. The traps were operational for three In localities A and B, traps were placed along two continuous days in four sampling months from June until transect lines placed on the same isohypse. In locality A, September 2009. transect line T1 contained 28 pitfall traps (traps 1–8 in 2.2. Data analyses the forest fragment, trap 9 in the ecotone, 10–18 in the The distribution of the specimens was analyzed using two open space, 19 and 20 in the next ecotone, 21 and 22 in approaches: 1) comparison of the carabid distribution the open space (grassland), 23 in the ecotone, and 24–29 between four microhabitats and 2) comparison of their in the forest of the same fragment). Transect T2 contained distribution between three localities, A, B, and C. 32 pitfall traps (traps 1–9 placed in the forest fragment, Species abundance data were tested for normality 10 in the ecotone, 11–18 in the open space, 19–21 in the of distributions and variance of homogeneity by using ecotone, 22 and 23 in the forest, 24–26 in the ecotone, and Shapiro–Wilks and Levene tests, respectively. To obtain 27–32 in the forested part of the same locality). normal distributions, data were log(x + 1) transformed. Figure 1. Jamiško Osoe study area with 3 localities (A, B, and C) and transects T1–T7 (gray color represents beech forests, black – potato fields, and white – mountain pastures and forest clearings). 403 HRISTOVSKI et al. / Turk J Zool During the analyses normal distribution and homogeneity with cluster analysis. When studying clustering of carabid of variance were not obtained, so nonparametric tests, such assemblages among localities, Bray–Curtis paired grouping as the Kruskal–Wallis test followed by the Mann–Whitney (clusters were joined based on the average distance U test, were applied to examine the differences of average between all members in the two groups) was used. beetle abundance between microhabitats and localities, Seasonal dynamics and sex structure were examined, and the results were presented as box plots. Spearman rank as well. The collection of specimens was performed in June correlation was used to analyze the relationship between (12–14), July (3–5), August (17–19), and September (4–6) the average number of captured specimens and the type of 2009. locality, microhabitat, or month. The sex of the collected specimens was determined in In order to analyze structural characteristics of carabid the field by checking the sexual differences, mainly the communities, indices of richness – d (Margalef, 1958), protarsal segments (normal in females, widened in males). evenness – J(e) (Pielou, 1966), dominance – D (Balogh, All statistical data analyses were done with statistical 1958), and Shannon–Wiener diversity – H’ (Glowacinsky, programs PAST and STATISTICA 6. Significant values 1975) were used. These indices were used in order to were those with P < 0.05. compare the microhabitats and localities although the Assessment of the mobility of ground beetles in the pitfall-trapping method may be biased toward actively investigated area was done on the basis of recaptured moving, large-sized species and does not always represent specimens of the larger species that were marked with the true composition and structure of carabidocoenosis unique numbers and colors. (Koivula, 2011). In order to estimate the number of taxa that were expected 3. Results to be found in a sample with the smallest total number of The total dataset consisted of 1320 individuals representing individuals, an individual rarefaction test was used. 19 species.