Road Verges Are Important Secondary Habitats for Grassland Arthropods
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Journal of Insect Conservation (2019) 23:899–907 https://doi.org/10.1007/s10841-019-00171-9 ORIGINAL PAPER Road verges are important secondary habitats for grassland arthropods Hardeep Kaur1,2 · Attila Torma1 · Nikolett Gallé‑Szpisjak2 · Jelena Šeat1,3 · Gábor Lőrinczi1 · Gábor Módra1 · Róbert Gallé1,2 Received: 18 February 2019 / Accepted: 29 July 2019 / Published online: 6 September 2019 © The Author(s) 2019 Abstract Semi-natural linear landscape elements such as road verges, hedgerows and feld margins are important in maintaining the connectivity between habitat fragments of highly modifed landscapes. Preservation of habitat specialist fauna requires conservation of the remaining natural habitat patches and connectivity of fragments. Our study focuses on the spider, ant and true bug fauna and functional diversity (FD) of fragmented forest steppe patches, moderately grazed pastures and road verges embedded in a matrix of forest plantations in Hungary, Central Europe. We established total 30 sampling sites, 10 in each, the grassland component of forest-steppes (F), pastures (P) and road verges (R) near pine forests. We collected arthropods with pitfall and sweep-net techniques. We calculated FD and species composition of arthropods using linear mixed models. We observed higher species richness in road verges for spiders and ants. We also found higher FD values for spiders and diferent trait composition for all taxa in road verges when compared with forest steppes and pastures. Species composition suggests that road verges do not serve as habitat for several forest-steppe and grassland species, in spite of the fact that numerous specialist species were found in the road verges. We show that forest steppes have higher species richness of spiders than pastures, and there are diferences in species assemblage composition of the two habitat types for all taxa. Our results indicate that road verges should be considered as an important refuge for grassland specialist arthropods, as road verges provide secondary linear habitats for many arthropod species, and we would suggest the maintenance of these grassy strips in order to preserve arthropod biodiversity. Keywords Managed forest · Functional diversity · Secondary habitat · Forest steppe · Pasture · Road verge Introduction Preservation of habitat specialist fauna in fragmented habi- tats requires conservation of natural habitat patches and In fragmented agricultural landscapes of Europe, the avail- connectivity of fragments. Artifcial linear landscape ele- ability of natural, semi-natural habitats has been highlighted ments (LLEs) are landscape structures established for a as the limiting factor for the conservation of populations. special function such as transportation on roads and drain- age by ditches, but they have a part covered by vegetation, which is not directly used for its original function, and may Electronic supplementary material The online version of this potentially constitute semi-natural habitats. It is shown that article (https ://doi.org/10.1007/s1084 1-019-00171 -9) contains a signifcant proportion of native biota can survive in LLEs supplementary material, which is available to authorized users. such as ditch banks (Torma et al. 2018) feld margins and * Hardeep Kaur hedgerows (Ernoult et al. 2013; Gallé et al. 2018a; Haal- [email protected] and et al. 2011; Morandin and Kremen 2013), road and railway verges (Henneberg et al. 2017; Jakobsson et al. 1 Department of Ecology, University of Szeged, Közép fasor 2018; Noordijk et al. 2009). These LLEs are important in 52, Szeged 6726, Hungary conserving various arthropods and other animals as they 2 MTA Centre for Ecological Research, Institute of Ecology can decrease isolation efect of fragmented habitats (Dover and Botany, Lendület Landscape and Conservation Ecology, Vácrátót, Alkotmány u. 2-4., Vácrátót 2163, Hungary et al. 2000; Hinsley and Bellamy 2000; MacDonald 2003; Hollmen et al. 2008) and also, they function as corridors 3 HabiProt, Janka Čmelika 28a/25, 21000, Novi Sad, Serbia Vol.:(0123456789)1 3 900 Journal of Insect Conservation (2019) 23:899–907 and refuges for species within highly modifed landscapes Arthropods represent a widely used indicator group in (Zanden et al. 2013). Road verges between patches, for conservation studies, as they are highly diverse and present example, proved to have importance in conserving grass- in almost every terrestrial and aquatic habitat. They inter- land specialist fauna in Ireland (Fuller et al. 2013) and also act with various other groups and are important mediators Noordijk et al. (2009) showed that apart from indigenous of ecosystem. In our study, we focused on three arthropod species of ants, grasshoppers, spiders, ground beetles, bees taxa, spiders (Araneae), true bugs (Heteroptera) and ants and butterfies, road verges were able to save several threat- (Hymenoptera: Formicidae). Spiders are among the most ened species of grasshoppers and bees in intensively used abundant invertebrate predators, that play a decisive role in landscapes in the Netherlands. LLEs can help in increasing the regulation of other invertebrate assemblages (Clarke and species movements across the fragment habitat (Gilbert- Grant 1968; Moulder and Reichle 1972; Weeks and Holtzer Nortan et al. 2010). Although, road verges in fragmented 2000). The diversity of spiders is afected by a number of habitats usually undergo management activities like mowing environmental factors that directly control their microhabitat and subsequently changing the composition of communities. requirements (Ziesche and Roth 2008). True bugs are the Careful management and preservations of road-side verge largest and most diverse group of hemimetabolous insects. can help to protect biota (Le Viol et al. 2008; Decleer et al. They comprise phytophagous, zoophagous and omnivorous 2015). feeders (Fauvel 1999). Their presence in particular habitat Forest-steppes are defned as an alternation of forest refects habitat condition primarily determined host plants patches within steppe grasslands forming a mosaic-like for phytophagous and omnivorous species, whereas vegeta- structure (Erdős et al. 2014). An extensive forest-steppe belt tion structure and prey availability specify the suitable habi- has been developed in the Eurasian temperate zone under tat for zoophagous species (Gallé et al. 2010). Ants are one semi-humid to semi-arid climate, and it runs from the Pan- of the most ecologically important animal groups in many nonian lowland to China. The westernmost occurrence of terrestrial ecosystems. They are highly diverse, abundant, forest-steppe is in the Hungarian Great Plain, where open sensitive to change in the environment and can provide cost forest patches are embedded in xeric grasslands (Erdős efective and efcient data compared to other invertebrate et al. 2018). Since grasslands are characterized by a higher groups (Andersen and Majer 2004). They play complex role temperature and lower humidity than forests, both habitat as predators, herbivores, seed-dispersal agents and soil engi- types have their own specialised fauna (Gallé et al. 2018b). neers (Hölldobler and Wilson 1990). Any change in their Hungarian forest-steppes have lost more than 93% of their micro or macrohabitat such as shading efect, soil type or original areas during the past 200 years. The most important vegetation cover directly afect their community structure threatening factors of this habitat type and its high of conser- in nature (Andersen et al. 2002). Ants respond quickly to vation value invertebrate fauna are aforestation, overgrazing changes in their habitat such as the clearing of forests (Majer and desertifcation due to the drop of groundwater table and et al. 1997), road construction (Lassau and Hochuli 2004), climate change (Molnár et al. 2012). anthropogenic disturbances or agricultural practices (Evans The majority of forest steppes in Hungary are altered by et al. 2011) hence, are reliable bioindicators. anthropogenic activities such as forest management to meet Traditionally, species richness has been used as a diver- the growing forestry demands and to stabilize the sandy sity measure of ecosystems, neglecting the functional diver- soil in open grasslands (Molnár et al. 2012). In addition to sity (FD) approach. However, change in the FD of species native deciduous forest plantations, exotic species like black corresponds to all the functions provided by these species locust (Robinia pseudoacacia) and scots pine (Pinus syl- in an ecosystem, thereby being able to predict ecosystem vestris) were introduced to the Great Hungarian Plain at the processes, dynamics and stability (Petchey and Gaston beginning of the seventeenth and at the end of the nineteenth 2006). Therefore, FD provides a more accurate picture of century, respectively (Redei et al. 2008; Masón and Alía the change of ecosystems due to changes in habitats (Díaz 2000). In this region, there also exists extensive sandy grass- and Cabido 2001). lands, that are regularly used for pasture and maintained by In this research, we aim to study the species richness and sheep or cattle grazing thus they are in a semi-natural form FD of the arthropod fauna of forest-steppe patches, pastures, (Biró et al. 2013). Intensive management of these grass- and road verges within exotic forest plantations. We focus lands threatens biodiversity (Dengler et al. 2012). However, on addressing the following questions: (1) Do linear grassy grasslands with sparse woody vegetation and are