Contribution to the knowledge of the arthropods community inhabiting the winter-flooded meadows (marcite) of northern Italy

Abstract Background Flooded semi-natural grasslands are endangered ecosystems throughout Europe. In Italy, amongst flooded meadows, one special type called “marcita” is strongly threatened. It is a stable flooded grassland used to produce green forage even during winter months due to the thermal properties of water coming from springs and fountains that prevent the soil from freezing. To date, some research has been carried out to investigate the role of the marcita for ornithological and herpetological communities. However, no comprehensive data on invertebrates inhabiting this particular biotope available. The aim of this study was to characterise the terrestrial entomological community of these typical winter-flooded meadows in northern Italy and, in particular, in six marcita fields located in the Ticino Valley Regional Park. We collected data on species richness and diversity of Carabidae, Staphylinidae, Araneae, Lepidoptera and Orthoptera inhabiting marcita during the summers of 2014 and 2015 and data on overwintering Coleoptera during the winter of 2014-2015. Amongst the collected species, we identified those highly linked to this habitat. New information We found a total of 47 ground beetle species, 35 rove beetle species, 29 spider species, one Lucanidae, 16 butterfly species and 24 grasshopper and cricket species. Most of the species were collected during the summers of 2014 and 2015, while some others were also, or exclusively, overwintering (17 ground beetles, four rove beetles and one Lucanidae) and were collected during the winter of 2014-2015. Marcita fields hosted specialised species and species typical of hygrophilous habitats, amongst which are included the butterfly Lycaena dispar, the ground beetle Dolichus halensis and the grasshopper Chrysochraon dispar. This study represents the first contribution to the knowledge of terrestrial arthropod communities associated with this particular type of winter-irrigated meadow in Europe and confirms the importance of this biotope for invertebrate conservation in agricultural landscapes.


Introduction
Flooded semi-natural grasslands are highly productive biotopes that support characteristic animal species communities (Prach et al. 1996). Until the early twentieth century, they were widely distributed throughout Europe: in Germany, Belgium, Switzerland and Sweden (Leibundgut and Kohn 2014), in addition to Italy. Later, they fell into disuse and gradually disappeared from the landscape. The main causes of their decline, both in extent and quality, are mechanisation and intensive agriculture which led to a change in land use over the last 50 years (Saarinen et al. 2003, Van Buskirk andWilli 2004). Intensive practices for semi-natural water meadows include higher fertiliser and herbicide applications and the use of modern mowing techniques (Van Buskirk and Willi 2004). This results in eutrophic, structurally poor and homogeneous meadows with negative impacts on diversity, species composition and ecosystem processes (Hans et al. 2020).
In northern Italy and, in particular, in the Po Plain, a typical winter-flooded meadow, the so called "marcita" (pronunciation: maarcheeta), is still present, but highly threatened. The marcita is a traditional agricultural practice used to produce green forage for domestic animals throughout the year. This agriculture system exploits the thermal properties of water coming from springs and fountains to prevent soil from freezing during periods of intense cold and, due to a network of canals skilfully controlled through sluice gates and earth ridges, a thin layer of water flows smoothly and continuously over the ground during the winter months, allowing a perennial growth of the vegetation (Tomaselli 1960, Ferrari andLavezzi 1995). This masterpiece of hydraulic engineering is due to water regimentations that Cistercian monks began in the late thirteenth century by reclaiming the marshes that occupied a large part of the Po Plain. The marcita spread consistently from the end of the XVIII century, when modern agriculture brought the development of a more capillary irrigation network (Brown and Redondi 2016).
In the past, the socio-economic role of the marcita has been extremely high; farmers could annually carry out 7-8 cuts of green forage, with 3-4 of them collected during the winter. However, since the second World War, the changing agronomic and zootechnical requirements made the marcita economically disadvantageous, leading to its progressive conversion into more profitable crops, such as corn, wheat or barley (Gomarasca 2002, Origgi andGuarisco 1992). Therefore, this traditional practice, which, for centuries, was one of the typical and supporting elements of the rural economy of the Po Plain, has now remained as a relict in an agricultural landscape mainly dominated by monocultures (Gomarasca 2002). Today, it survives mainly thanks to the subsidies paid to farmers by some park authorities.
Beyond the importance of the marcita as a mixture of cultivation, artwork and historicalcultural elements to preserve, in the last few years, its naturalistic and environmental value has also been recognised . Indeed, the marcita, inserted in a context of intensive agriculture, increases landscape diversity and its aesthetic value. Due to its floristic composition, partly made up of leguminous plants, it has the ability to use atmospheric nitrogen, which reduces or eliminates the need for external inputs, such as fertilisers, agrochemicals and fossil fuels . Moreover, regulating the water cycle, the marcita protects soil from erosion and leaching of nutrients . The low anthropic pressure, together with the presence of water and vegetation during cold months, allows this habitat to host a rich biodiversity, acting as a refuge and feeding and resting sites for different animal species of conservation interest, especially during the winter season (e.g. amphibians -Gentilli et al. 1997;birds -Casale 2015 andCasale et al. 2016).
Even if some research has been carried out to investigate the role of the marcita for ornithological and herpetological communities, to date in Italy, no comprehensive data on invertebrates inhabiting this particular biotope are available. Beyond the conservation interest on their own, many arthropods may play key roles in the maintenance of this ecosystem functioning, feeding on soil invertebrates (Wise et al. 1999), serving as prey for small mammals, amphibians and birds (Holland et al. 2007, Rodríguez andBustamante 2008) and being natural enemies of crop pests and weeds (Ichihara et al. 2014, Symondson et al. 2002.
Ground beetles (Coleoptera, Carabidae), rove beetles (Coleoptera, Staphylinidae), spiders (Araneae), butterflies (Lepidoptera), grasshoppers and crickets (Orthoptera) are amongst the most common, well-studied and species-rich groups of arthropods in agricultural landscapes and are often used as environmental indicators of human impacts and habitat quality (Báldi and Kisbenedek 1997, Wise et al. 1999, Holland and Luff 2000, Bubová et al. 2015, Marc et al. 1999, Courtney et al. 1982. Table 1. Coordinates (latitude and longitude in datum WGS84) of the six investigated Marcita fields and their altitude.
within each month because, during summer, farmers take turns in irrigating the fields. As a consequence, the traps were kept active for 10 days in each field and month, making sure with farmers that irrigation would not take place during those days.
Coleoptera (ground beetles, rove beetles and Lucanidae) were also sampled during November and December 2014 in all six marcita fields by actively and opportunistically searching for overwintering species in suitable natural and artificial places along the banks, such as dead woods, barks, stones, wooden boards and earthen banks. Beetles and spiders were preserved in hermetic bottles containing 70% ethanol solution and transported to the laboratory for identification.
Butterflies were sampled in Sforzesca, Tre Colombaie and Casterno fields from April to October 2014. A two-hour long visual census was carried out every two weeks along a 100 m linear transect for a total of 14 sampling dates. Individuals were captured with an entomological net, photographed and then released. During 2015, the butterfly Lycaena dispar was opportunistically searched for in all six marcita fields.
Grasshoppers and crickets were sampled in all six marcita fields from May to September 2015. A two-hour long visual census was carried out monthly along a 100 m linear transect for a total of seven sampling dates. Individuals were sampled by the casual positioning of a transparent plexiglas cylinder, 1 m high and about 30 cm in diameter and by manual collection; specimens were preserved in hermetic bottles containing ethyl acetate and sawdust, placed in a refrigerated bag and transported to the laboratory for identification. The six marcita fields in north-western Italy. In grey, the boundaries of the Ticino Valley Regional Park (Lombardy area) and, in black, the Ticino River.
All taxa were identified to the species level by experts (see Acknowledgements) and following the nomenclature of: "Fauna Europaea web project" (De Jong et al. 2014) for ground beetles, rove beetles and butterflies; (World Spider Catalog 2020) for spiders; Massa et al. (2012) for grasshoppers and crickets.
In order to assess the role of marcita as a refuge for sensitive species, we selected ground beetles and grasshoppers and crickets as model groups of predatory and herbivorous species. These two groups are well studied (Hůrka 1996, Homburg et al. 2013, Reinhardt et al. 2005, Massa et al. 2012) and information on their ecology and morphology at species level is more exhaustive compared to others taxa. Ground beetles and grasshoppers and crickets were grouped, based on their morpho-ecological features, focusing on their dispersal capability, adult diet and habitat specificity. Specialised species, such as apterous and predatory ones, are known to be spread throughout permanent, undisturbed habitats (Reinhardt et al. 2005, Gobbi andFontaneto 2008) and their persistence in agricultural landscapes could be highly enhanced by habitat patches with low anthropic pressure Bogliani 2014, Giuliano and.
For ground beetles, data on wing development and adult diet were derived from Hůrka (1996), Brandmayr et al. (2005), Homburg et al. (2013) and, when not available from literature, from specialist knowledge. The species have been classified as brachypterous (with reduced wings, not suitable for flight), macropterous (with developed wings, suitable for flight) and dimorphic (with both brachypterous and macropterous individuals) and therefore, respectively, with low, high and medium dispersal ability (Brandmayr et al. 2005). As for diet, species were classified as predators, omnivorous and phytophagous. Wing development and diet provide useful information on the level of disturbance and stability of the environment, with wingless and strictly predatory species negatively affected by human impacts (Ribera et al. 2001, Gobbi andFontaneto 2008). Conversely, mobile, omnivorous species are expected to perform better in disturbed and fragmented habitats due to their major dispersal ability and capacity to use different food resources.
For grasshoppers and crickets, we collected information on dispersal capabilities and habitat specificity. These features are considered important factors in determining species sensitivity to habitat loss and human disturbance, with sedentary and habitat specialist taxa often more susceptible to local extinction events (Reinhardt et al. 2005). Dispersal capabilities were measured using the Mobility Index developed by Reinhardt et al. (2005). Each species was classified into one of three broad mobility classes: sedentary, intermediate dispersers and mobile species. All apterous and brachypterous orthopterans were classified as sedentary, while readily-flying species were assigned as mobile. Furthermore, for species with wing dimorphism (i.e characterised by a solitary or gregarious phase), we considered the most common form observed in the collected sample. Concerning habitat specificity, each species was assessed according to its moisture preferences, following the procedure reported by Reinhardt et al. (2005). We assigned orthopteran species to one of three broad classes: habitat specialists, medium specialised species and generalists. Xerothermophilous and hygrophilous species were classified as habitat specialists, while orthopterans with broad ecological requirements were considered as generalists. The species not treated by Reinhardt et al. (2005) and Notes: It is a hygrophilous species that lives in low vegetation, meadows and litter. It is a night hunter (Isaia et al. 2007).
Notes: It is a xerophilous species that lives in the undergrowth, on tufts of grass, sometimes on chalk or marl. It is a night stalker (Roberts 1995, Isaia et al. 2007).

Ozyptila simplex O. Pickard-Cambridge, 1862
Distribution: Sibiric-European species (Isaia et al. 2007). It is distributed in Europe and Turkey (World Spider Catalog 2020). It can be found in mainland Italy (Pantini and Isaia 2019); in Lombardy, it is reported only in the Province of Pavia (Isaia et al. 2007).
Notes: It lives amongst the bases of plants and in detritus, usually in sandy habitats. It is sometimes found higher up on low vegetations (Roberts 1995). It is a night stalker (Isaia et al. 2007).

Xysticus gallicus Simon, 1875
Distribution: Sibiric-European species (Isaia et al. 2007). It is distributed in Europe, Turkey, Caucasus and Iran (World Spider Catalog 2020). It can be found in mainland Italy (Pantini and Isaia 2019); in Lombardy, it is reported only in the Provinces of Bergamo and Sondrio (Isaia et al. 2007).
Notes: It lives in the low vegetation in the pine forests or in the rocky moors, under stones and in detritus from the plains to the alpine areas (Harvey et al. 2002). It is a night stalker (Isaia et al. 2007).

Xysticus kochi Thorell, 1872
Distribution: Sibiric-European species (Isaia et al. 2007). It is distributed in Europe, from the Mediterranean area to Central Asia (World Spider Catalog 2020). It can be found in mainland Italy, Sardinia and Sicily (Pantini and Isaia 2019).
Notes: It is common to find it in low vegetation, on bushes and in the undergrowth. The species prefers warm, dry conditions, provided by open and sparsely-vegetated habitats, such as ruderal habitats, dunes and vegetated pebbles. Adults of both sexes are found mainly in May and June, but females can sometimes survive until autumn (Harvey et al. 2002). It is a night stalker (Isaia et al. 2007).
Notes: Macropterous. Lives indifferent to moisture or very moist habitats, to entirely shaded: forests, parks and shaded water edges; from lowlands to mountains, often in hills (Hůrka 1996).

Notes:
Macropterous. It is a hygrophilous species of shaded borders of waters with rich vegetation in floodplain forests; it can be found in lowlands (Hůrka 1996).

Notes:
Macropterous. Lives indifferent in the shade: steppe, vineyards and floodplain groves; it can be found in lowlands (Hůrka 1996).
Notes: Macropterous. Lives on borders of swamps amongst soaking wet vegetation; it can be found in lowlands (Hůrka 1996).
Notes: Brachypterous, rarely macropterous. It is a very eurytopic species of fields, meadows, gardens, as well as forests; from lowlands to mountains (Hůrka 1996).

Notes:
Macropterous. Lives in moist habitats, indifferent to shade: meadows, forests, water margins with vegetation; from lowlands to mountains, frequently in hills (Hůrka 1996).
Notes: Brachypterous, more frequently macropterous. Prefers moist habitats, indifferent to shade: floodplain forests, meadows near water, margins of waters with vegetation and forest clearings; from lowlands to mountains (Hůrka 1996).

Notes:
Macropterous. Lives in moist to wet habitats, indifferent to shade: grassy water shores, moist meadows, floodplain forests and gardens; from lowlands to mountains (Hůrka 1996).

Notes:
Macropterous. Lives on marshy borders of irrigation canal; it can be found in lowlands (Hůrka 1996).

Notes:
It has a larval biology linked to the presence of rotting wood in deciduous and sometimes coniferous forests (Boucher 2014, Franciscolo 1997.

Notes:
Lives in open habitats. In particular, adults can be found in rotting Brassica and other vegetation and it is associated with carrion and dung (Andreassen 2013).
Notes: Frequently found on dung, carrion and other decomposing organic matter (Majka and Klimaszewski 2012).

Astrapaeus ulmi Rossi, 1790
Distribution: Europe (except in the northern part) and it reaches western Turkey (Pietrykowska-Tudruj et al. 2014). Its occurrence is patchy and it is generally considered a rare species (Assing and Schülke 2012). In Italy, the species is present along the peninsula, in Sicily and in Sardinia (Ruffo and Stoch 2005).
Notes: As a thermophilus species, inhabits xerothermic habitats with moderately moist soil. Many authors collected the adults in open grassy sites with some layers of humus, under heaps of rotting plants or stones and often in riverside areas covered with low vegetation (Pietrykowska-Tudruj et al. 2014).

Atheta fungii Gravenhorst, 1806
Distribution: Under the name Atheta fungii, considered a widespread Palaearctic species, a very difficult complex of taxa is included (Zanetti et al. 2016, Sushko 2016. In Italy, the species is widespread (Ruffo and Stoch 2005).
Notes: It is a saprophilous species widespread from the plains to middle altitude elevations (1000 m). It is a very common predator and it is found mostly in decaying vegetable matter (Lupi et al. 2006).
Notes: Common in decaying plant material and also found on carrion and dung. It is found in the nest of several birds species (Majka and Klimaszewski 2012).
Distribution: Europe, Turkey and North America (ITIS Species 2000 2020). The species is present only in the Italian pensinsula (absent in the Islands) (Ruffo and Stoch 2005).

Notes:
Found in open areas under vegetation, stone, mosses and decomposing materials. A very eurytopic species adapted to a wide range of ground conditions: it can be found on dry, heathy and sandy soils; on damp loam and in humic soils; in wet soil and Sphagnum. Often found in proximity of ants (Majka and Klimaszewski 2012).
Distribution: Palearctic species (Zanetti 2007). In Italy, it is present along the peninsula and in Sicily (Ruffo and Stoch 2005).
Notes: Lives in the rotting wood of several broad-leaved species (Zanetti 2007).
Notes: Lives in both lowlands and mountain areas, mainly in moist mixed and deciduous forests. It can be found under fallen leaves, in mosses, in compost and rotting hay and straw, and in mountains under stones in moist places (Majka and Klimaszewski 2012).
Notes: Found in many kinds of decaying organic matter such as animal dung, compost piles and decaying vegetation; also in leaf litter and debris and amongst low vegetation in moist habitats; often around gardens and farmhouses (Majka and Klimaszewski 2012).
Notes: It is a migratory pest that causes serious economic damage every year. Seems to be polyphagous in its larval stage, but it has been reported to have obvious hostplant selection for many crops (sugar beet, potato and soybean) and pastures (Wei et al. 2017).
Notes: Common from the foothills up to about 1400 m. In the hills, it flies from early June to the first ten days of July, in the mountains throughout the month of July (Flamigni and Bastia 1998). Schmidt, 1931 Distribution: From North Africa across Europe to East Asia (Wagner 2020).

Timandra comae
Notes: Inhabits many habitats in which the larval host plants (Rumex spp.) occurs, such as woodlands clearings and edges, extensively-managed meadows and pastures or shores and wetlands. Has 2-3 (in the south also 4) generations from May to September. The caterpillar overwinters. It is observed quite frequently on leaves and fruit stands (Wagner 2020).

Lycaena dispar Haworth, 1802
Conservation status: Least Concern for Italian (Balletto et al. 2015) and European assessments ( Notes: Hygrophilous species, it lives in humid meadows from the plain up to 500m a.s.l. Trivoltine species, with generations in April-May, June-July, August-September (Paolucci 2013, Villa et al. 2009).
Distribution: It is distributed in Canary Islands, North and east-central Africa, Europe, temperate Asia, Japan and northeast America (Tolman and Lewington 2008). It can be found in mainland Italy, Sardinia and Sicily (IUCN, 2020, Villa et al. 2009).
Notes: Eurycora species widespread and locally common, it frequents flowery meadows, open hedges, grasslands with scattered patches, pastures, moors and grassy banks, from the plain up to 2000 m a.s.l. Trivoltine species with generations in April-May, June-July, August-September (Paolucci 2013, Villa et al. 2009).
Notes: It is one of the largest migratory moths in the world. It is common and often abundant. Polyvoltine, flies almost all year round both at night and during the day. It frequents a great variety of environments because its larvae feed on many different herbaceous species (Sterry and Mackay 2005).

Notes:
It is a small, partly plurivoltine noctuid moth. It is generally occurring in a wide variety of grassy sites, perhaps most commonly in somewhat sheltered situations. The larvae feed on various grasses and it is also recorded from sedges. The adults are long-lived and there is then a succession of at least partial additional generations, such that adults are on flights more or less continuously from late May well into September, with summer generation larvae in various stages of growth from June until the third instar larvae start to enter diapause in the autumn (Shaw 2012).

Aglais io Linnaeus, 1758
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Eurycora species, it lives in open and sunny places, in the woods, wooded banks, humid meadows, uncultivated fields and disturbed ground, rocky gullies sheltered with bushes and small trees at the upper limit of the altitude. It is spread from the plain at 2500 m a.s.l. Univoltine species flies in June-July (Paolucci 2013, Villa et al. 2009).

Vanessa cardui Linnaeus, 1758
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Migratory species widely distributed in many different environments, from the plains to 2500 m a.s.l. Migratory individuals arriving in Italy have two generations in June-July and September-October (Paolucci 2013, Villa et al. 2009).

Colias alfacariensis Ribbe, 1905
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Thermophilic migratory species, it is found in arid grasslands, stony grasslands and rocky slopes from the plain at 1900 m a.s.l. Trivoltine species with generations in April-May, June-July and August-September (Paolucci 2013, Villa et al. 2009).

Pieris rapae Linnaeus, 1758
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Eurycora and migratory species very widespread in every environment from the plain to 2300m a.s.l., especially in prairies, cultivated areas and arid meadows. It has four generations in March-April, June, August and September-October (Paolucci 2013, Villa et al. 2009).

Coenonympha pamphilus Linnaeus, 1758
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Widespread in a wide range of habitats, often in arid and flower-rich meadows, mountain pastures and rugged fields from the plain to 2100 m a.s.l. It is also found in peatlands and wet meadows. Bivoltine species with generations in April-May, July-August, sometimes a third in October (Paolucci 2013, Tolman and Lewington 2008, Villa et al. 2009).

Maniola jurtina Linnaeus, 1758
Conservation status: Least Concern for Italian (Balletto et al. 2015), Mediterranean (Numa et al. 2016)  Notes: Widely distributed, often abundant; it is common to all types of pasture, such as flowery meadows, grassy slopes, neglected cultivated areas; it is also found along open hedges and wooded edges from the plain to 1500 m a.s.l. Univoltine species flies in June-July (Paolucci 2013, Tolman and Lewington 2008, Villa et al. 2009).
Distribution: Mediterranean area and Africa (Fontana et al. 2002). In Italy, it is widespread in the whole of the country (Sicily and Sardinia included), with some discontinuity in northern Italy (Baroni et al. 2018, Iorio et al. 2019, Massa et al. 2012.
Notes: It is a thermophilous species, living in all kinds of dry habitats, wet grassland, dunes and wasteland. The adults can be found in summer and autumn (Fontana et al. 2002, Massa et al. 2012.
Distribution: Europe and northern Africa to the Caucasus and Middle East (Fontana et al. 2002). Widespread all over in Italy (Sicily and Sardinia included), also on many small islands (Massa et al. 2012, Iorio et al. 2019. Notes: It is a thermophilous species (Fontana et al. 2002), living in habitats with sparse vegetation like dry grassland, roadside verges and forest clearings. Adults can be found throughout the year, even during warm days in winter, while the highest densities occur in autumn (Massa et al. 2012).
Distribution: Europe, Africa and Asia (Fontana et al. 2002). In Italy, it is widespread in the whole country (Sicily and Sardinia included), but often discontinuously (Baroni et al. 2018, Iorio et al. 2019, Massa et al. 2012.
Notes: It is a hygrophilous species, often living in brackish habitats (Fontana et al. 2002). In Italy, it seems to be in decline (Iorio et al. 2019, Massa et al. 2012.
Distribution: From Europe to Ukraine (Fontana et al. 2002). In Italy, it is widespread throughout the mainland, with a few records in Sardinia (Iorio et al. 2019, Massa et al. 2012. Notes: It is a xerothermophilus species. It lives in dry, stony and sunny meadows, in clearings and at the edge of the woods. Sometimes, it behaves like a hygrophilous species and inhabits fresh and wet meadows and swampy areas. The adults can be found from July to September (Fontana et al. 2002).
Distribution: Southern Europe, Mediterranean area, Africa and Asia (Fontana et al. 2002). In Italy, it is widespread in the whole country (Sicily and Sardinia included), but recently, it is much scarcer in the north (Iorio et al. 2019, Massa et al. 2012.
Notes: Lives in wet habitats with high grasses and herbs and sandy soil. Adults can be found in summer and autumn (Fontana et al. 2002, Massa et al. 2012.
Distribution: Central and eastern Europe, widespread from Asia to Siberia. In Italy, it is widespread in the northern part, but rare in the Alpine arc (Iorio et al. 2019, Massa et al. 2012).

Notes:
The species is typical of wet grassland, where it lives in the high vegetation. The adults can be found from June to October. In Italy, it seems to be in decline (Massa et al. 2012).
Distribution: Wide distribution, from Europe and North Africa (Fontana et al. 2002). In Italy, it is widespread over the whole country (Sicily and Sardinia included) (Iorio et al.

2019, Massa et al. 2012).
Notes: It lives from the sea level to 2300 m in the mountains, in grasslands, wasteland, forest clearings, urban and agricultural habitats. This species has two generations in one year and can be found from May to November. It is one of the few species living in the Padanian Plain, in cultivated fields, too (Fontana et al. 2002, Massa et al. 2012.
Distribution: It is distributed in south Europe, North Africa as far east as Caucasus (Fontana et al. 2002). In Italy, it is widespread in the whole country (Sicily and Sardinia included), also on several small islands (Iorio et al. 2019, Massa et al. 2012.
Notes: It is a thermophilus species and lives in many different open habitats. It lives in meadow environments, preferably mesoxerophilous; it can frequent mountain stony and arid stony environments. The adults appear from June to October, but it is frequent to observe them in autumn during the mating season (Fontana et al. 2002, Massa et al. 2012.
Distribution: It is distributed from Europe to Siberia. In Italy, it is widespread in the Alps and Apennines. From Sardinia, there is a doubtful record (Fontana et al. 2002).
Notes: It is a mesohygrophilus to hygrophilus montane species. The adults can be found in summer and autumn in dry to moist grassland (Fontana et al. 2002).

Tetrix subulata Linnaeus, 1758
Conservation status: Least Concern for European assessment .
Distribution: Widely distributed species in Eurasia and North America (Fontana et al. 2002). In Italy, it is recorded in many localities in the mainland, while with single records in Sicily and Sardinia (Iorio et al. 2019, Massa et al. 2012. Notes: It is a meso-hygrophilous or hygrophilous species and lives from the coast up to 1700 m a.s.l. More frequent in lowland areas, submontane up to 1000 m a.s.l. It often forms abundant populations, located in fresh and humid habitats. It is an early species that overwinters as a nymph or adult insect (Fontana et al. 2002).

Notes:
It is a small meso-hygrophilous species. It is common from the coast to submontane habitats, up to 1100 m a.s.l (Fontana et al. 2002). It forms abundant population in the slightly moist parts of dry grassland, along irrigation canals or in irrigated meadows. The adult can be found throughout the year, even if the species probably winters as a nymph (Massa et al. 2012).

Platycleis grisea subsp. grisea Fabricius, 1781
Distribution: Central, southern and eastern Europe to southern Russia. In Italy, it is widespread over the whole country, most abundant in the northern regions. In Sicily, it is known only from Etna (Iorio et al

Distribution: Widespread species, from central-southern Europe to Palearctic Asia and
Africa (Fontana et al. 2002). In Italy, it is widespread all over the country (Sicily and Notes: Meso-hygrophilous or hygrophilous species, it inhabits all kinds of open habitats with a high rate of humidity and dense vegetation. It is frequent in agricultural fields, grasslands, banks of rivers, lakes and canals and also in brackish wetlands. It also lives in urban environments (Fontana et al. 2002, Massa et al. 2012).

Analysis Data analysis
Statistical analysis was conducted exclusively on ground beetles, rove beetles and spiders sampled by pitfall traps because only these taxa had a sufficient amount of quantitative data available. For spiders and beetles, immature specimens and larvae, respectively, were not considered in the analysis because, for many of them, it was not possible to determine the species. For the other groups, only descriptive tables have been prepared.
To examine whether trap locations were sufficiently spaced to be independent replicates, we tested our data for autocorrelation by performing a Mantel test, based on Pearson's product-moment correlation (permutations: 9999) between Bray-Curtis distances in assemblage composition and the geographical distances of samples collected. We found that spatial correlation in assemblages between samples was low (Person's r = 0.43) and not significant (p ≥ 0.05). Therefore, we assumed all sampling plots as statistically independent (inter-sample distance ≥ 10 m). From hereafter, each trap is called a plot and each field (with six plots) a site.
The mean number of species and individuals per plot was calculated and the difference in species richness amongst sites was evaluated with the Kruskal-Wallis non-parametric analysis of variance. Differences amongst individual factor levels was tested by Wilcoxon pairwise rank sum tests.
Differences in species richness amongst sites was also evaluated by computing a sample size-based rarefaction curve using the software iNEXT (interpolation/extrapolation) R package (Hsieh et al. 2016). iNEXT focuses on three measures of Hill numbers (Hill 1973) of order q: species richness (q = 0: the relative abundances of species are not considered and, therefore, the value obtained is equal to that of species richness), Shannon diversity (q = 1: the index weighs the species, based on their frequency and the result is the exponential version of the Shannon Index) and Simpson diversity (q = 2: the abundant species have a higher weight and the result is the inverse of the Simpson concentration).
For each diversity measure, iNEXT uses the observed sample of abundance data to compute diversity estimates, calculated via the functions ChaoRichness for q = 0, ChaoShannon for q = 1 and ChaoSimpson for q = 2; (see Chao et al. 2014 for the formulae of these asymptotic estimators). The 95% confidence intervals associated with the estimates are also calculated and a sample-size-based rarefaction and extrapolation (R/E) curve is plotted.
In order to verify differences in species composition amongst the marcita fields, we performed a PERMANOVA (permutational multivariate analysis of variance) analysis, using Primer 6+ statistical software with the PERMANOVA + add-on package (Anderson et al. 2006, Clarke andGorley 2006). The analysis was conducted on a Bray-Curtis similarity matrix in which abundance raw data were standardised by dividing the number of individuals of each species collected in each plot by the total number of individuals collected in that plot. These data were then square-root transformed to underestimate the contribution of the more abundant species (Clarke 1993, Bray andCurtis 1957). Pairwise post-hoc tests to compare similarities in species composition amongst sites were performed under 9999 permutations (for further details, see Anderson 2005). Whenever the sample size was too small once divided into factors, PERMANOVA's Monte Carlo test, which uses chi-square variables, combined with eigenvalues to construct the asymptotic permutation, was used.
We also used the Bray-Curtis similarity matrix in a distance-based Redundancy Analysis -dbRDA (Anderson andCribble 1998, Ramette andTiedje 2007) to display differences in species composition amongst all samples and the contribution of individual species to these differences. The contribution of each species in determining the dissimilarity between pairs of marcita fields was measured using the SIMPER test (Anderson et al. 2006, Clarke andGorley 2006) which provides a percentage measurement of this contribution according to a decreasing dissimilarity order.

Results
During the whole sampling period we found a total of 47 ground beetle species, 35 rove beetle species, 29 spider species, one Lucanidae, 16 butterfly species and 24 grasshopper and cricket species. Specifically, between April and October 2014, we found a total of 4449 ground beetles belonging to 41 species (Table 2); 1698 spiders belonging to 29 species (Table 3); 589 rove beetles belonging to 34 species (Table 4); 45 butterflies belonging to 16 species (Table 5). During the winter 2014/2015, we collected 618 overwintering beetles belonging to 22 species divided as follows: 17 ground beetle species, four rove beetle species and one species belonging to Lucanidae (Table 6).

Casterno Sforzesca Tre Colombaie
Agonum (  List of ground beetle species collected in the three marcita fields of the study area during the summer of 2014. For each species, information is reported for wing development WD (M = Macropterous, winged species; D = dimorphic, a species that can be either winged or not winged; B = Brachypterous, species without wings or reduced ones) and diet D (P = Predator, OM = Omnivorous, PHY = Phytophagous).
List of butterflies collected in the three marcita fields of the study area during the summer of 2014.  Table 6.
List of the overwintering beetles collected in the six marcita fields of the study area during the winter of 2014-2015. For ground beetles species, information is reported for the wing development WD (M = Macropterous, winged species; D = dimorphic, a species that can be either winged or not winged; B = Brachypterous, species without wings or reduced ones) and diet D (P = Predator, OM = Omnivorous). Between May and September 2015, we found a total of 262 grasshoppers and crickets belonging to 24 species (Table 7) and we confirmed the presence of Lycaena dispar at the "Amerio 2" field in the Sforzesca area.   Table 8.
Species richness and diversity of ground beetles during summer 2014. The Table shows the observed diversity, the asymptotic estimates (Estimator), the estimated bootstrap S.E. and 95% confidence intervals (LCL and UCL) for Hill numbers of order q (0: Species richness, 1: Shannon diversity and 2: Simpson diversity).

Ground beetle richness and abundance
During the summer of 2014, carabid assemblage in the whole study area was dominated by macropterous individuals (4331 out of 117, for a total of 38 species), both omnivorous and predators (Table 2). We found only two brachypterous species, Calathus (Neocalathus) melanocephalus and Microlestes minutulus, both predators, for a total of five individuals and one dimorphic species, Carabus (Carabus) granulatus (n = 112), which is also a predator. Amongst the collected ground beetles, we found only one phytophagus species: Diachromus germanus. The most abundant species was Pseudoophonus ( Pseudoophonus) rufipes with more than 1000 specimens, followed by Metallina (Metallina) properans and Harpalus (Harpalus) affinis with more than 500 specimens (Table 2).
Although Casterno resulted in the field with the lowest number of species (Wilcoxon rank sum test: Casterno vs. Tre Colombaie, p = 0.024; Casterno vs. Sforzesca p = 0.036), it Rarefaction curves showing the diversity of a) ground beetles; b) spiders; c) rove beetles, in the three marcita fields when the order q was set at q = 0 (species richness), q=1 (exponential Shannon index) and q=2 (Simpson index).
showed a more equitable species abundance compared to the other two fields. Therefore, as shown in Fig. 2, Casterno is the field with the highest Shannon and Simpson diversity.
The PERMANOVA test revealed differences in species composition amongst the fields (Table 9). In particular, Casterno was significantly different from Sforzesca and Tre Colombaie (Table 10) showing a low frequency of some species, such as Pseudoophonus (Pseudoophonus) rufipes and Harpalus (Harpalus) affinis, that were otherwise significantly abundant in the other two fields (Table 2). Species composition differed also between Sforzesca and Tre Colombaie (Table 10). The species that contributed the most to the dissimilarity between the two fields was Harpalus ( Harpalus) affinis, which was clearly more abundant in Tre Colombaie (Table 11). The significantly different species composition is indicated by bold p-values obtained by permutation. Table 9.
Results from permutational multivariate analysis of variance for differences in species composition amongst the fields, based on a Bray-Curtis resemblance matrix with P-values obtained by 9999 permutations. Table 10.
Results from permutational multivariate analysis of variance pairwise tests for differences in species composition between pairs of fields.  Table 11.
Results from SIMPER analysis for differences in species composition amongst the three marcita fields. This analysis shows which species contribute the most to dissimilarity between pairs of fields and provides a percentage of this contribution in a decreasing dissimilarity order. Ordinations with db-RDA confirm differences in species composition amongst the three communities (Fig. 3). In particular, the first axis explains 45% of the total variance and clearly separates Casterno from Sforzesca and Tre Colombaie ground beetle communities. The second axis, with 23% of the total variance explained, separates Sforzesca from Tre Colombaie communities. In the cloud of species projected in the db-RDA graph, also less frequent species are present. Amongst them, those collected only on one occasion are: Harpalus (Harpalus) serripes and Pterostichus (Melanius) aterrimus in the Tre Colombaie field, Bembidion ( Bembidion) quadrimaculatum, Sphaerotachys hoemorrhoidalis and Stenolophus ( Egodroma) marginatus in the Casterno field, Parophonus ( Parophonus) maculicornis and Amara (Amara) similata in the Sforzesca field.

Spider richness and abundance
The whole spider community analysed has 1698 specimens with a slightly unbalanced sex ratio in favour of males (1019 vs. 763 females). Pardosa proxima (Lycodidae) was the most abundant species with 731 specimens mainly sampled in Tre Colombaie (Table 3), followed by Pachygnatha degeeri (Tetragnathidae), with 251 specimens mainly sampled in Casterno, Oedothorax apicatus (Linyphiidae) with 226 specimens equally distributed amongst the fields and Arctosa leopardus (Lycosidae) with 188 specimens mainly sampled in Casterno (Table 3).
Spider richness ranged from 25 species in Casterno to 19 and 15 species in Tre Colombaie and Sforzesca, respectively (Table 12). The higher diversity value of the Casterno community remains constant as the order q changes (Fig. 2). Conversely, Tre Colombaie and Sforzesca showed, respectively, a decrease and an increase in the diversity value as the order q increased. The mean species richness did not differ significantly amongst the three marcita fields (Kruskal-Wallis chi-squared = 5.48, df = 2, pvalue = 0.065). However, the higher number of species, found in Casterno, makes this value very close to significance.  Distance-based redundancy analysis (dbRDA) ordination plot of ground beetle, spiders and rove beetle assemblages in the three marcita fields (Casterno: triangle; Tre Colombaie: inverted triangle; Sforzesca: square) Species composition differed significantly amongst the fields (Table 9). Similarly to ground beetles, spider species sampled in Casterno were also very different from those sampled in Tre Colombaie and Sforzesca (Table 10). Casterno is characterised by the presence of a very abundant species, the Tetragnathidae Pachygnatha degeeri, which is almost completely absent in the other two fields. This species contributes to 21.4% of the dissimilarity between Casterno and Tre Colombaie and 21.7% of the dissimilarity between Casterno and Sforzesca (Table 11). Conversely, species composition of Tre Colombaie and Sforzesca were similar.

Sites
Ordinations with db-RDA confirm differences in species composition amongst the three communities also highlighting the species that contribute most to this difference (Fig. 3).
The first axis explains 38.4% of the variance (53% total variance from the first two axis) and clearly separates Casterno from Sforzesca and Tre Colombaie spider communities. The second axis, with 14.6% of total variance explained, separates Sforzesca from Tre Colombaie communities. In the cloud of species projected in the db-RDA graph,10 species sampled exclusively in Casterno and three species sampled exclusively in Tre Colombaie are also shown (Table 3).

Rove beetle richness and abundance
During summer 2014, rove beetle richness ranged from 21 species in Tre Colombaie to 18 and 16 species in Sforzesca and Casterno, respectively (Table 13). Although there was a high number of species in Tre Colombaie, the mean species richness did not differ significantly amongst the three marcita fields (Kruskal-Wallis chi-squared = 1.21, df = 2, pvalue = 0.545). Moreover, rove beetle communities from Casterno and Sforzesca fields showed very similar values of Shannon and Simpson indices (   (Table 4).
The PERMANOVA test revealed differences in species composition amongst the three fields (Tables 9, 10). Ordinations with db-RDA confirmed differences in species composition amongst the three communities (Fig. 3) and the first axis, explaining 39.1% of the total variance, clearly separated Sforzesca from Casterno and Tre Colombaie rove beetle communities. In the cloud projected in the db-RDA graph, the species that characterises each community is clearly visible. The species that contributed the most to dissimilarity between fields was Philonthus (Philonthus) cognatus, contributing to 15.5% of the dissimilarity between Sforzesca and Tre Colombaie and 15.8% of the dissimilarity between Sforzesca and Casterno (Table 11).

Butterfly richness and abundance
Amongst butterfly families, the most representative one was that of Pieridae with three species (Table 5). The most abundant species belonging to this family was Pieris rapae, which is found mainly in Sforzesca. All the other families had two species with the exception of Hesperiidae with only one member. Tre Colombaie was the most diversified field with at least one species per family and four exclusive species: Pyrausta despicata, Pyrgus sp., Autographa gamma and Vanessa cardui, while Sforzesca was the leastdiversified one with only five families out of eight. However, this was the only field where two Lycaenidae are present: Lycaena dispar (also sampled in the other two fields) and Lycaena phlaeas (Table 5). Finally, the species Colias alfacariensis and Loxostege sticticalis were found exclusively in Casterno.

Overwintering beetle richness and abundance
The largest number of collected species during winter 2014-2015 belongs to the ground beetle family (Carabidae) (  (Table 6).
Staphilinidae was the most abundant family found in Sforzesca. Amongst rove beetles (four species), the most abundant was Paederus ( Heteropaederus) fuscipes with 408 specimens, almost all collected in Casterno (Table 6).
The other collected family has only one representative: Dorcus parallelepipedus (Lucanidae) with only two specimens found exclusively in Tre Colombaie.

Grasshopper and Cricket richness and abundance
Amongst the grasshoppers and crickets, the most representative family was Acrididae with a number of species much higher than the other families ( Table 7). The most abundant species were the Acrididae Pseudochorthippus parallelus with 55 specimens and Aiolopus thalassinus with 48 specimens (Table 7).
Concerning ecological traits, the orthopteran assemblage was dominated by highly mobile species (11 out of 20 identified species), followed by eight intermediate dispersers species and one sedentary species, Roeseliana azami. Medium specialised species represent a large proportion of the community observed in the winter-irrigated meadows investigated (n = 10), while habitat specialist (n = 5) and generalist (n = 5) orthopterans were less common.

Ground beetle community
Most of the beetle individuals sampled in marcita fields during the summer of 2014 were macropterous (i.e. with high dispersal ability) and omnivorous, adapted to living in periodically-disturbed sites, such as watercourses or grasslands (Rainio and Niemelä 2003). In perturbed habitats, species face an elevated risk of local extinction and the ability to relocate by flight to new favourable patches when resource availability suddenly changes is essential to survival (Ribera et al. 2001, Gobbi andFontaneto 2008). Moreover, omnivorous species, due to their wide trophic niche breadth and great resilience to reductions in food supply, better persist in stochastic environments (Purtauf et al. 2004, Schweiger et al. 2005).
However, we also found two brachypterous, Calathus (Neocalathus) melanocephalus and Microlestes minutulus, one dimorphic, Carabus (Carabus) granulatus and a conspicuous number of predatory species (23 out of 41, constituting 56% of the collected individuals). The presence of these species confirms that traditional agricultural habitats, such as marcita, could contribute to the persistence of individuals with low dispersal ability and also of strictly predatory species in intensive agroecosystems (Brandmayr et al. 2005, Cardarelli andBogliani 2014).
Even if we did not find any endemism, we recorded the presence of Dolichus halensis, that has been identified as a focal species of wet meadows of the Po Plain (Bogliani et al. 2007). We also unfortunately confirmed the disappearance from the investigated marcita fields of Carabus (Limnocarabus) clatratus antonellii, documented as closely associated with this biotope (Bucciarelli 1963) and extinct in the Ticino Park for over 30 years, despite the apparent persistence of the habitat that was considered suitable.
Casterno was the field with the lowest number of species, but with the highest Shannon and Simpson diversity. All the species found in Casterno were equitably distributed showing this site to have more stable environmental conditions (Death 1996)

Spider community
Collected spiders were all very common and quite frequent (Nentwig et al. 2020), with the only exception being Ceratinella brevipes, a rare, detrital species that lives both in woodlands and grasslands (Hansen 2010). Half of the species was linked to wet environments, but only two of them can be considered stenohygrophilous: Gnathonarium dentatum (Linyphiidae) and Pirata tenuitarsis (Lycosidae) (Hansen 2010).
Both Linyphiidae and Lycosidae were very abundant in this study. Linyphiidae are the most abundant spiders in temperate regions (Samiayyan 2014) and this is probably the main reason why they were so frequently captured in our samples. Moreover, the use of pitfall traps can partially explain the abundance of Lycosidae, as this family includes species living and hunting on the ground and so easily interceptable by pitfall traps (Green 1999). Both these families are also typical of highly dynamic ecosystems, especially those disturbed by frequent flooding (Buchholz and Schröder 2013), as marcita. Many Lycosidae, such as Arctosa leopardus and Pardosa proxima s.l., recorded in high numbers in our fields, are specialised for living in wet habitats with temporal flooding, while Linyphiidae are able to rapidly recolonise disturbed areas and survive flooding through ballooning (Hayashi et al. 2015, Holland et al. 2007).
Most of the collected individuals were males. Indeed, males, because of their matesearching behaviour (Lang 2000, Collins et al. 1996, are more mobile and, therefore, more easily intercepted by traps.
Concerning the spider community in the three marcita, Casterno resulted in being significantly different from the other two fields. In Casterno, spiders species, belonging to Lycosidae and Linyphiidae, were almost double those found in Tre Colombaie and Sforzesca, making this field the richest in species. Moreover, rarefaction curves showed higher species diversity and a more equitable distribution of the species abundance in Casterno compared to the other two fields where few, very abundant species were found. PERMANOVA and db-RDA also showed how Casterno hosted a well-characterised community that greatly differs from those of the other two fields. Casterno was the only field to host the rare Ceratinella brevipes and the stenohygrophilous Pirata tenuitarsis. Moreover, in this field, some hygrophilous species, such as Pachygnatha degeeri, Arctosa leopardus and Trochosa ruricola, were very abundant.
On the other hand, analyses showed a very poor spider community in Sforzesca and Tre Colombaie. Most of the species collected in the two fields, including the exclusive captures, such as Palliduphantes pallidus and Ozyptila sanctuaria, were less related to wet environments and, therefore, in general, less indicative of this type of habitat.

Rove beetle community
All the rove beetles sampled during the summer of 2014 were good flyers of open habitat, with wide distribution and ecological value. The only exception was Ocypus ( Matidus) brunnipes, a flightless species that inhabits both forested and open disturbed areas (Deichsel 2006). Only Ochthephilum brevipenne was exclusively linked to wet habitat, as it is usually found in ponds, along watercourses, in marshy meadows and near the seashore (Bordoni et al. 2006). All other species can be found also in less humid habitats and one species, the uncommon Astrapaeus ulmi, is thermophilous and mainly lives in xerothermic plant communities (Wojas 2011).
Most of the species were predators, linked to meadows or non-cropped areas (Zanetti et al. 2016). Amongst them, Ocypus (Ocypus) olens, recorded in all studied fields even if in low number, is known to be a species sensitive to agricultural practices (Daccordi and Zanetti 1989), highlighting the lower pressure to which this traditional agricultural habitat undergoes with respect to conventional, intensive crops. According to what was found for ground beetles, marcita may act as a refuge from detrimental agronomic practices for more sensitive species (Bordoni et al. 2006, Wojas 2011. The number of rove beetle species was very similar amongst the three marcita. Most of the species were shared between fields and, according to the rarefaction curves, species abundance of the three communites are equally distributed. db-RBDA showed a less clear distinction amongst the rove beetles of the three fields compared to what was observed for spiders. However, PERMANOVA analyisis revealed the existence of a different species composition amongst the three marcita fields. About 20% of the species was found exclusively in one of the three fields. In particular, the flightless Ocypus ( Matidus) brunnipes was collected only in Casterno, while the hygrophilous Ochthephilum brevipenne and the thermophilous Astrapaeus ulmi were exclusively found in Tre Colombaie. Again, Casterno seems to host species more typical of humid and well-preserved habitat compared to those more common and generalist collected in Tre Colombaie and Sforzesca. Amongst the commonest species shared between Sforzesca and Tre assessed as "Vulnerable" in Mediterranian regions, in Europe and throughout the world ) and of Mecostethus parapleurus and Chrysochraon dispar. Mecostethus parapleurus is typical of humid environments, such as swamps, water meadows and peat bogs and is threatened and rare in the Italian territory (Tami et al. 2005, Baroni 2015. Chrysochraon dispar is a hygrophilous and stenotherm species inhabiting marshes, swamps, wet meadows and brackish biotopes (Nadig 1986). It is a rare and protected species in France, Germany, Austria and Switzerland (Detzel 1998). In Italy, the degree of threat for this species is still unknown, but it is probably at risk of extinction (Tami et al. 2005). Currently, Chrysochraon dispar has been found only in Trentino and Alta Val Venosta, with the subspecies C. dispar dispar (but here could already be extinct), while in Veneto, in Friuli-Venezia Giulia and in Venice Lagoon, with the subspecies C. dispar giganteus (Tami et al. 2005). In the Lombardy Region, the species was recently found in the Ticino Valley Regional Park (Roberto Scherini, pers comm). The maintenance and, where possible, the re-naturalisation of wet areas is considered essential to guarantee the species survival (Tami et al. 2005).
Again, as already pointed out for the other investigated taxa, the presence of extensivelymanaged habitats in agro-ecosystems, such as marcita, may also provide refuge to species more sensitive to human disturbance (Giuliano et al. 2018).

Overall arthropod community in the investigated fields
Overall, the winter-flooded meadow system of our study area hosted a rich and diverse entomofauna with indicator species of a hygrophilous environment, such as the butterfly Lycaena dispar, the ground beetle Dolichus halensis and the grasshopper Chrysochraon dispar. However, the arthropod communities of the investigated fields differed from each other in terms of site specificity, species richness and species composition.
In particular, Casterno field stands out for having a high number of exclusive species in all taxa, including two spiders of high conservation value, such as Ceratinella brevipes and Pirata tenuitarsis. Tre Colombaie field is undoubtedly the richest both for the presence of a large number of species in all taxa and to host exclusive, "priority" species, that are also indicators of a wet environment, such as Dolichus halensis. Sforzesca field, although neither stands out for species richness nor for the presence of exclusive species, also hosts specialised species and species of conservation relevance, such as the butterfly Lycaena dispar, the two brachypterous ground beetles Calathus melanocephalus and Microlestes minutulus and the stenohygrophilous spider Gnathonarium dentatum. However, these are also species found in the other two fields, so they do not give Sforzesca a uniqueness.
There are no differences in the agronomic management of the three marcita fields. In all of them, the winter flooding has been practised for at least five years and mowing has been carried out 3-4 times during the summer season. The only field that has been periodically fertilised is Casterno, but taking into account the high degree of diversity found in the three marcita, fertilisation is probably not a determining factor influencing the biodiversity. Likely, the differences amongst sites is found in the landscape diversity, as the mosaic of habitat surrounding the field (e.g. hedgerows, old isolated trees, small woodlots) could determine the facility with which specialised species could colonise the marcita fields at first and then after disturbing events, such as the periodic mowing and flooding.
On the other hand, the practice of winter flooding could be considered crucial to guaranteeing the presence of species of wet habitats. In fact, amongst the marcita investigated in 2015, the only one to be completely devoid of hygrophilous species was the Amerio 1 which, until 2013, was subjected to total abandonment and in which the winter flooding was carried out exclusively during the winter 2014-2015. The situation was slightly better in Amerio 2, where the meadow management resumed a year earlier than Amerio 1 and lasted until 2016. This certainly favoured the presence of Lycaena dispar.
The only field investigated in 2015, in which a winter flooding was comparable to that of Casterno, Sforzesca and Tre Colombaie was carried out, was at "Garlaschè" field. It is the only one in which Chrysochraon dispar, a rare and strongly indicative species of wet environments, has been observed.

Conclusion
This study represents the first comprehensive contribution to the knowledge of terrestrial arthropod communities associated with the winter-irrigated meadows, the so-called marcita, in Europe. Our investigation showed that marcita fields hosted specialised species (e.g. brachypterous, predators) and species typical of hygrophilous habitats. This result confirms the importance of marcita for invertebrate conservation, as already stated for other taxa, such as amphibians and birds (Casale 2015, Gentilli et al. 1997. It also highlights the importance for biodiversity conservation, to preserve traditional and extensive crops as refuge habitats in highly intensive and exploited agroecosystems, such as that of the fertile Po Plain in Italy ).
Moreover, marcita plays a significant role in terms of the ecosystem services provided: they may be a source of bio-controllers through their important bulk of predatory species detected amongst carabids, rove beetles and spiders, that could move to surrounding fields, contributing to limit crop pests (Nyffeler andSunderland 2003, Symondson et al. 2002). Pest regulation has been demonstrated to be strengthened by complementarity amongst natural enemies, guaranteed by a various guild of natural enemies (Dainese et al. 2017).
Finally, marcita has an undeniable aesthetic value, as they are considered a "Rural traditional landscape of Italy" by MIPAAF , contributing to increasing the landscape beauty of the area.
Since the late eighties, the Ticino Valley Regional Park is making a huge effort in terms of incentives to farmers to preserve and restore these winter-flooded meadows , together with events to bring back the cultural and historical value of this crop to the attention of local people. A plan to support the re-activation of a sustainable production chain, aiming to re-introduce this high-quality forage in the local zootechnical practices ) and sensitise the consumers on the quality of dairy products obtained from green forage (Elgersma et al. 2006) would certainly help to increase the attraction of this crop amongst farmers.
Obviously, the work to be done is still demanding. A more synergic conservation effort amongst local and regional managing bodies is desirable to restore, where possible, this precious habitat and to retain the biodiversity linked to it.