Land snails benefit from human alterations in rural landscapes and habitats

Abstract

Citation: Rosin, Z. M., A. Lesicki, Z. Kwiecinski, P. Skorka, and P. Tryjanowski. 2017. Land snails benefit from human alterations in rural landscapes and habitats. Ecosphere 8(7):e01874. 10.1002/ecs2.1874Abstract. Metapopulation functioning in the context of landscape and habitat structure is generally well understood. However, in human-transformed landscapes, human disturbance may affect not only a species of interest but also biotic interactions in which that species is engaged, which has been rarely studied at multiple spatial scales. We tested (1) the associations between local (habitat and micro-habitat) and landscape factors and the occurrence and abundance of the land snail Cepaea nemoralis and two of its predators (thrushes and mice); and (2) the hypothesis that human disturbances modify associations between C. nemoralis and its predators. We surveyed snail colonies in rural landscapes of Poland. Generalized linear mixed models were used to test the stated hypotheses. At the landscape scale, the occurrence of C. nemoralis colonies was positively related to the cover of suitable habitats, fallow/waste land, and road length in the surrounding landscape. Bird predator abundance was positively correlated with the occurrence of snail colonies, mostly at sites with a high human impact, and was negatively correlated with snail abundance at sites with low human disturbance. Snail occurrence and abundance at the micro-habitat scale were positively correlated with variables describing the proximity of shelter and humidity. Avian predation pressure was negatively correlated with forest and settlement cover, whereas rodent predation pressure was positively associated with snail abundance and was negatively correlated with bird abundance. Human disturbance at the habitat and landscape scales benefited C. nemoralis through the creation of suitable habitats and scaling down of avian predation pressure. Conditions related to shelter and humidity were linked to the distribution and abundance of snails at the micro-habitat scale.

Functional connectivity in replicated urban landscapes in the land snail (Cornu aspersum)

“…The amount of borders associating wooded areas and roads or wooded and impervious areas was related to increased population differentiation and by consequence showed a barrier effect. Wooded areas are not an optimal habitat for C. aspersum (Falkner et al., ) or other land snails (Rosin, Lesicki, Kwieciński, Skórka, & Tryjanowski, ). At this local scale, the proximity of wooded areas to roads (or other impervious areas) resulted in fragmented wooded patches and may have decreased habitat quality.…”

Shell colour, temperature, (micro)habitat structure and predator pressure affect the behaviour of Cepaea nemoralis

“…Surveys were conducted in two large plots located in rural landscapes in the vicinities of Gdańsk (54° 20′ N, 18° 38′ E; plot area 251 km 2 ) and Poznań (52° 26’ N, 16° 52′ E; 252 km 2 ) (Rosin et al 2017 ). Cepaea nemoralis colonies were searched for in randomly selected potential habitats (fallow lands, hedges, ecotonal fragments of forests).…”

“…Each colony was surveyed three times: between 1st May and 30th June, 1st July and 31st August, 1st September and 31st October 2012 (Rosin et al 2017 ). The minimal interval between visits in a colony was 30 days.…”

“…In each colony, the snails were counted in 50 cm × 50 cm squares, spaced 5 m apart along a transect of 20 m (5 squares per transect). Depending on the colony area, the number of transects ranged from 1 to 5, and the distance between adjacent transects was 5 m. The location of the square plots and the number of transects in a colony varied across visits, and the latter also depended on colony area (Rosin et al 2017 ). Each live specimen was scored for shell colour (yellow, pink or brown) and banding pattern (zero, one, three or five).…”

Fitting Competing Models of the Population Abundance Distribution: Land Snails from Nikopol Manganese Ore Basin Technosols

“…The habitat preferences of the land snail Vertigo geyeri in Poland and Slovakia were effectively explained by Ellenberg phytoindication scales (Schenková et al, 2012). Human disturbance at the habitat and landscape scales benefited Cepaea nemoralis through the creation of suitable habitats (Rosin et al, 2017).…”