Railway Embankments as New Habitat for Pollinators in an Agricultural Landscape

Abstract

Pollinating insect populations, essential for maintaining wild plant diversity and agricultural productivity, rely on (semi)natural habitats. An increasing human population is encroaching upon and deteriorating pollinator habitats. Thus the population persistence of pollinating insects and their associated ecosystem services may depend upon on man-made novel habitats; however, their importance for ecosystem services is barely understood. We tested if man-made infrastructure (railway embankments) in an agricultural landscape establishes novel habitats that support large populations of pollinators (bees, butterflies, hoverflies) when compared to typical habitats for these insects, i.e., semi-natural grasslands. We also identified key environmental factors affecting the species richness and abundance of pollinators on embankments. Species richness and abundance of bees and butterflies were higher for railway embankments than for grasslands. The occurrence of bare (non-vegetated) ground on embankments positively affected bee species richness and abundance, but negatively affected butterfly populations. Species richness and abundance of butterflies positively depended on species richness of native plants on embankments, whereas bee species richness was positively affected by species richness of non-native flowering plants. The density of shrubs on embankments negatively affected the number of bee species and their abundance. Bee and hoverfly species richness were positively related to wood cover in a landscape surrounding embankments. This is the first study showing that railway embankments constitute valuable habitat for the conservation of pollinators in farmland. Specific conservation strategies involving embankments should focus on preventing habitat deterioration due to encroachment of dense shrubs and maintaining grassland vegetation with patches of bare ground.

Invasive flora within urban railway areas: a case study from Lublin (Poland) and Lviv (Ukraine)

“…Railway transport systems with associated structures (e.g., tunnels, bridges) can also encourage biodiversity in an urban environment [20]. These structures create new habitats and provide valuable conditions for the activity of animals and/or the occurrence of diverse plant species [16,21,22]. However, there are also many negative impacts of railway areas on the environment such as habitat loss and fragmentation, destruction of habitat conditions, pollution, creation of barriers to the reproductive and food niches of organisms [23].…”

Distribution and abundance of bee forage flora across an agricultural landscape – railway embankments vs. road verges

“…Positive effects of flower abundance on the pollinator population size have been demonstrated for bumblebees [43], solitary bees [44], and butterflies [45]. According to Moroń et al [19], in an agricultural landscape, railway embankments support the diversity and abundance of pollinators (bees, butterflies, hoverflies) even better than typical habitats for these insects, i.e., semi-natural grasslands. In fact, nutrient diversity enhances insect life cycles, protects them from many chronic diseases, and thus is decisive for their abundance [7].…”

“…However, a growing body of evidence shows that linear structures may benefit rural areas by creating important zones for general diversity of fauna [2,14] and flora [15][16][17]. The ecological value of habitats along road verges and railway embankments for pollinators is related to a number of functions, i.e., sites for nesting, mating as well as food sources for larvae and adults [3,18,19].…”

Railway embankments - a refuge areas for food flora, and pollinators in agricultural landscape

“…In the modern agricultural landscape, pollinators suffer from an acute scarcity of flowering plants and are under nutrition stress. These factors can bring on a number of complications, including a weakening of the pollinators immunological system (Moroń et al, 2009(Moroń et al, , 2014. Several studies indicate that the population dynamics of bees, hoverflies, dipterans, and butterflies favour habitats with a mosaic structure of vegetation in an area (Wratten et al, 2012).…”

“…On the other hand, there is a lot of evidence that railway lines create important biotops for general diversity of fauna (e.g. Moroń et al, 2014;Kalarus & Bąkowski, 2015) and flora (Wrzesień, 2009). In this study, we evaluated the bee forage flora distribution, richness, and diversity along railway embankments in relation to (i) the type of railway with regard to the traffic volume, and (ii) the microhabitats along an embankment cross section.…”