The effect of landscape on functional connectivity and shell shape in the land snail Humboldtiana durangoensis.

Benjamín López,Gerardo Zúñiga,Omar Mejía

doi:10.7717/peerj.9177

Abstract

The populations of Humboldtiana durangoensis have experienced a drastic reduction in the effective population size; in addition, the species is threatened by anthropogenic activities. For the aforementioned, landscape genetics will serve as a tool to define the potential evolutionarily significant units (ESU) for this species. To complete our objective, we evaluated the effect of cover vegetation and climate on the functional connectivity of the species from the last glacial maximum (LGM) to the present as well as the effect of climate on shell shape. Partial Mantel tests, distance-based redundance analysis and a Bayesian framework were used to evaluate connectivity. On the other hand, geometric morphometrics, phylogenetic principal component analysis and redundancy analysis were used for the analysis of shell shape. Our results suggest that the suitable areas have been decreasing since the LGM; also, vegetation cover rather than climate has influenced the genetic connectivity among land snail populations, although temperature had a high influence on shell shape in this species. In conclusion, vegetation cover was the main factor that determined the functional connectivity for the land snail; however, local selective pressures led to different phenotypes in shell shape that allowed us to postulate that each one of the previously defined genetic groups must be considered as a different ESU.

Highlights

IntroductionSpecies dispersal can be affected by essential processes (e.g., the movement, mating and reproductive fitness of the individuals) and by ecological and topographical factors (e.g., abiotic variables, land cover, line features and landforms) associated with the landscape (Manel et al, 2003; McRae et al, 2008)
Species dispersal can be affected by essential processes and by ecological and topographical factors associated with the landscape (Manel et al, 2003; McRae et al, 2008)
Environmental suitability and vegetation models The results obtained for the modeling of the distribution area of H. durangoensis in the Madrense Centro region showed that the models constructed for the three temporal frames were satisfactory (P = 0)

Summary

Introduction

Species dispersal can be affected by essential processes (e.g., the movement, mating and reproductive fitness of the individuals) and by ecological and topographical factors (e.g., abiotic variables, land cover, line features and landforms) associated with the landscape (Manel et al, 2003; McRae et al, 2008). Due to their low vagility, patchy distribution and preference for particular microhabitats (Dörge et al, 1999; Hylander et al, 2005; Aubry et al, 2006), land snails are excellent models for exploring the effects of landscape on the movement of individuals among suitable patches, or in other words, on the functional connectivity (Tischendorf & Fahrig, 2000). Neither the effect of vegetation cover nor the effect of the climate on functional connectivity have been explored yet

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Results

Discussion

Conclusion