Habitat Matrix Effects on Pond Occupancy in Newts

Abstract

In farmlands, the population viability of many amphibians is suspected to depend on the resistance the matrix of crop fields presents to movements between ponds and terrestrial sires and movements among ponds. Over recent decades the increase in cereal grouping at the expense of cattle breeding has caused a drastic change in habitat matrix in many European regions. We investigated the effect of such change on populations of three newt species (Triturus helveticus, T. alpestris, and T. cristatus) by comparing their abundances in sites that varied in amount of cultivated ground. A multivariate regression analysis of the relationship of newt abundance to both Pond and landscape variables demonstrated the negative influence of cultivated ground on abundance. The width of the uncultivated sector linking the pond to the forest was a good predictor of abundance after the influences of both pond area and fish presence were removed Moreover, newt presence was positively related to the number of ponds within that 50-ha surrounding area, highlighting the role of metapopulation functioning in newt occupancy of ponds. The relationship between newt abundance and width of uncultivated sectors agrees with present knowledge of the orientation mechanisms that underlie migration movements in urodeles Such a relationship between connectedness and sector width shows that narrow linear corridors such as hedgerows may not be useful in newt conservation. Our study, also highlights the need to incorporate a behavioral component of habitat use into models of connectivity in conservation biology

Spatial connectivity moderates the effect of predatory fish on salamander metapopulation dynamics

“…Because the distribution and movement patterns of amphibians can depend on matrix heterogeneity (Joly et al 2001, Stevens et al 2004, Mazerolle and Desrochers 2005, Rittenhouse and Semlitsch 2006, we also evaluated support for different models of connectivity. Desiccation risk has been identified as an important cost of movement for juvenile dispersers due to their small bodies, permeable skin, and high surface-area-to-volume ratio compared to adults (Spight 1968, Rothermel andSemlitsch 2002).…”

Distribution patterns and environmental determinants of European newts in the Montenegrin karst area

“…As far as breeding sites are concerned, the Montenegrin karst newts' aquatic preferences overall appear to fit into the general picture of the "preferable" newt breeding site (a water body with a relatively stable hydroperiod, with dense aquatic vegetation, intermediate pH, and ionic concentration, and without fish) (e.g., Arntzen & Teunis 1993;Ildos & Ancona 1994;Marnell 1998;Oldham et al 2000;Babik & Rafinski 2001;Joly et al 2001;Denoël et al 2005;Skei et al 2006;Denoël & Lehmann 2006). However, regarding the aquatic preferences of new species in the Montenegrin karst area, none of the breeding site characteristics could discriminate newt species, both in syntopy and allotopy.…”

“…The quality and quantity of these factors partially determine the presence of populations to the extent that some features can be isolated as of particular diagnostic importance and used as a basis for determining the likelihood of newt occurrence (e.g., Oldham et al 2000). Landscape characteristics, such as the density of nearby water bodies and the possible network of migration corridors (e.g., Joly 2001;Van Buskirk 2005), are very important because newts exhibit limited dispersal abilities, spawning-site fidelity and structuring as demes (Arntzen & Wallis 1991;Ficetola & Bernardi 2004;Smith & Green 2005;Jehle & Sinsch 2007). However, understanding of the newt-speciesdistribution causalities has been largely improved using spatial-environmental modeling of environmental characteristics in studies aimed at elucidating problems such as the determination of a species' range limits, the definition of the biogeographical history of species, and the impact of climate warming (e.g., Teixeira et al 2001;Teixeira & Arntzen 2002;Arntzen 2006;Skei et al 2006;Arntzen & Themudo 2008).…”

The importance of phenotypic diversity in conservation: Resilience of palmate newt morphotypes after fish removal in Larzac ponds (France)

“…Indeed, previous ecological modeling showed that paedomorphs are primarily favoured in deep and oxygenated waters . It is also likely that abundances depend on the size of wetlands (Joly et al 2001). Because previous ecological modeling showed the low effect of terrestrial variables on the distribution and abundance of paedomorphic palmate newts in Larzac (Denoël andFicetola 2014, 2015), only aquatic variables were taken into account in this study.…”