Movement of pond-breeding amphibians in fragmented landscapes : responses of great crested newt (Triturus cristatus) to road mitigation

With the increase of transportation system in the world, roads facilitate opportunities for human social and economic development. Roads are also the primary cause of multiple and diverse negative ecological effects. Habitat and wildlife populations are directly disturbed as roads contribute to habitat loss, habitat fragmentation and reduction of the quality of surrounding habitats. Barrier effects and traffic mortality are amongst the principal factors impacting species that need to move among important habitats to complete their life cycle leading to fragmentation, isolation and local population extinctions. Pond-breeding amphibians can be particularly impacted in this way, with mortality rates of 60-90% imposed by roads in some circumstances. Road mitigation measures, such as tunnels and associated fences, are implemented to manage this problem and restore connectivity at the landscape level in order to sustain migration and dispersal movements for amphibians and maintain metapopulation dynamics over the long-term.In the UK, the demand for the implementation of these mitigation infrastructures has increased in the past decade as urban development reached a detrimental point for the European Protected Species, Triturus cristatus, the Great Crested Newt. Road mitigation measures for newt species are notoriously difficult to implement efficiently due to the behavioural characteristics of this group and the poor understanding of how it influences road mitigation effectiveness. Their ability to climb vertical surfaces, the poor capacity for crossing large distances over land and general avoidance of small, narrow structures such as tunnels are some examples of responses that may influence how planning and design of mitigation can support and facilitate patterns of movements for the species. There is no clear understanding of how these responses and patterns influence successful crossings and dispersal in the long-term in the UK or the rest of Europe. Therefore, it is challenging to predict mitigation long term effectiveness, provide evidence-based guidance to developers despite their substantial costs and potentially crucial importance for maintaining connectivity and dispersal for this European protected species.The main aim of this study was to evaluate T. cristatus movement patterns in areas impacted by roads and at which road mitigation measures had been deployed in order to develop evidence-based improvements for the strategic planning and design of dispersal corridors for future mitigation. From a pitfall data monitoring scheme, I investigated the species’ behavioural traits at a road mitigation site to understand spatial and temporal patterns of movement. Also, I calculated regional connectivity indexes in a sub-urban area to understand the importance of spatial scale for movement when collecting species presence and absence data from local ponds. I measured short-term behavioural responses to a road mitigation system during two diferent seasons using non-invasive marking techiniques. And finally, I relate how local climatic factors affect successful crossings in tunnels and overall use of a mitigation system using standard monitoring data from previous chapter pitfall data. These results showed seasonality and yearly movements having an important role in calculating successful use of mitigation and directionality of movement. Newts’ movements were higher in the course of autumn dispersal than at other times of year, and movement between patches varied greatly among years. Fences operated as a barrier to dispersing newts, potentially preventing road mortality but also reducing dispersal. Landscape analysis showed how annual home-range position and size affects connectivity at regional level for newts when considering roads as barriers. Predicted dispersal patches increased with landscape permeability, which was associated with road type; minor roads were more permeable. Behaviour analysis towards responses in a road mitigation system showed distance of short-term movements changing significantly around the fences. These responses were independent of newts’ age. And finally, local weather patterns influenced newts’ successful crossings among years.These results showed the multi-scalar perspective of responses of T. cristatus to road mitigation systems and indicate the need to include consideration of multiple spatial and temporal scales when predicting the consequences of road construction and mitigation on T. cristatus metapopulation dynamics and hence conservation status. Identification of patterns of responses according to individual circumstance (age, sex) and climatic conditions facilitated calculation of potential landscape connectivity at distinctive spatial and temporal scales, and could inform improved advice for system design. Clear definitions of mitigation effectiveness have been repeatedly called for, but rarely offered. Here we have shown how spatial and temporal scales of newt responses need to be incorporated into these definitions, but also how variable they can be. Consequently, during and following road mitigation we recommend that newt responses should be monitored at these multiple scales to inform an adaptive approach to T. cristatus conservation when they are threatened by roads. The ultimate goal would be to include response patterns, scales and variability in a new iterative and innovative management tool that enables estimation of mitigation effectiveness for T. cristatus landscape connectivity over the short- to long-term

Short-term movements and behaviour govern the use of road mitigation measures by a protected amphibian

Road mitigation infrastructure for pond‐breeding amphibians aims to provide a safe and sustainable passage for individuals between critical habitat patches. However, relatively little is known about how amphibians interact with mitigation systems because of the challenges of documenting movements at sufficiently large sample sizes. The effect of real or perceived barriers to short‐term movement could ultimately determine the success or failure of road mitigation schemes. We quantified behavioural responses of the protected great crested newt Triturus cristatus in a complex road mitigation system in the UK. We used fluorescent paint to mark individuals in order to measure distance travelled and trajectory orientation over two seasons (spring when adults migrate to breeding ponds and autumn when newts disperse) and in three components of the mitigation system (fences, tunnel entrances and inside the tunnels). A total of 250 juveniles and 137 adult great crested newts were marked and tracked during 38 survey nights. Adults were individually identified using belly‐pattern recognition. There was substantially greater activity along the fences during autumn (82% of newt captures) compared to spring. Triturus cristatus typically moved short distances each night (3.21 m per night in spring and 6.72 m per night in autumn), with a maximum of 25.6 m travelled inside a tunnel. Adult recapture rates were low (9.7%) and only 3% of the newts found along the fences reached the tunnel entrances. Movements were straighter in spring and inside the tunnels and newts had higher crossing rates in autumn compared to spring. Overall, behaviour and seasonal movement patterns significantly influenced the use of the mitigation system, in a way that could impact landscape connectivity for T. cristatus over the long‐term. Adequate incorporation of fine‐scale movement dynamics could help develop new behavioural models, inform our understanding of amphibian ecology and substantially improve future road mitigation projects

Facilitating permeability of landscapes impacted by roads for protected amphibians: patterns of movement for the great crested newt.

Amphibian populations are highly vulnerable to road mortality and habitat fragmentation caused by road networks. Wildlife road tunnels are considered the most promising road mitigation measure for amphibians yet generally remain inadequately monitored, resulting in mixed success rates in the short-term and uncertain conservation benefits in the long-term. We monitored a complex multi-tunnel and fence system over five years and investigated the impact of the scheme on movement patterns of two newt species, including the largest known UK population of the great crested newt (Triturus cristatus), a European Protected Species. We used a stage descriptive approach based on capture positions to quantify newt movement patterns. Newt species successfully used the mitigation but the system constituted a bottleneck to movements from the fences to the tunnels. Crossing rates varied widely among years and were skewed towards autumn dispersal rather than spring breeding migration. There was a substantial negative bias against adult male great crested newts using the system. This study indicates that road tunnels could partially mitigate wider connectivity loss and fragmentation at the landscape scale for newt species. However, the observed bottleneck effects and seasonal bias could have population-level effects which must be better understood, especially for small populations, so that improvements can be made. Current requirements for monitoring mitigation schemes post-implementation are probably too short to assess their effectiveness in maintaining connectivity and to adequately understand their population-level impacts

Assessing Landscape Effects on Genetics and Dispersal of the Rocky Mountain Apollo Butterfly Parnassius smintheus using a Resistance Mapping Approach

Landscape variables that best explain genetic differentiation may not also best explain dispersal patterns, but many studies use genetic differentiation as a proxy for dispersal. I tested the effects of landscape on both genetic differentiation and dispersal in parallel, to explore whether landscape effects on genetic differentiation between populations and landscape effects on dispersal would be comparable in such contexts. I used circuit theory (Circuitscape) and least cost transect analysis to evaluate the effects of landscape on both movement and genetic differentiation of the butterfly, Parnassius smintheus, in the Jumpingpound Ridge study system. Circuit theory and least cost transect analyses did not identify the same best predictors to explain genetic differentiation and dispersal data. Circuit theory produced more accurate results with higher precision. Genetic differentiation should not be used as a sole proxy for dispersal in studies of landscape effects, but should be supplemented by more direct measures of dispersal

Translocation of a population of great crested newts (Triturus cristatus): a Scottish case study

In the UK, translocation is increasingly being used to resolve conflict between great crested newt (Triturus cristatus) conservation and land development. Due to a lack of objective study on the translocation procedure, there remains little evidence of the success of employing this strategy despite widespread implementation. Reviews of translocations highlight the need for case studies that include longer term pre and post translocation monitoring. To allow redevelopment of the Gartcosh Industrial Site, the decision was taken to translocate the resident great crested newt population to the purpose built Gartcosh Nature Reserve around the periphery. This provided an opportunity for in-depth analysis of the largest project of its kind in Scotland. This project was designed to test the effectiveness of translocation in producing a self-sustaining, viable population. The key aims were: to ascertain if the population was successfully re-established in the receptor site at a level comparable with the donor site; to assess whether the newly created habitat was suitable for supporting a population of great crested newts; to determine what constitutes a successful translocation and how best to achieve this within the Scottish context. The following points summarise the projects findings: • Simple counts of adults are being maintained at a level comparable to or greater than pre translocation counts. • The favourable status of the adult population is supported by a capture-mark-recapture study. Population estimates are on a par with numbers of adults translocated to the Gartcosh Nature Reserve. • Juvenile lifestages indicate declines. Further monitoring is required to determine if this is an effect of the translocation or a natural fluctuation. • Survival rate of adults is measured at 43%. • There is significant recruitment of ‘new’ adults. • Good quality terrestrial and aquatic habitat has been produced, with an overall loss of land and pond surface area but increased number of ponds. • Increased individual growth rates of adults are indicative of a habitat capable of meeting adult resource requirements. • The nature reserve is internally fragmented into zones preventing movement through the site and is isolated within the wider landscape. For the population to be viable, connectivity requires improvement. • To ascertain long-term success of the Gartcosh translocation it is recommended that post monitoring extends beyond simple adult counts and continues capture-mark-recapture study specifically within the Railway Junction area. • Guidelines have been produced detailing best practice in translocation, monitoring and habitat creation

Amphibian decline, pond loss and reduced population connectivity under agricultural intensification over a 38 year period

Habitat loss, together with less obvious land-use changes such as intensified farming practice, can have significant adverse impacts on biodiversity. An important factor in determining the ability of species to cope with such changes is their potential to sustain a populations network by dispersal across the landscape. Habitat quality and structure are particularly important for surface-dwelling species with low dispersal abilities, such as amphibians. To assess this ecological function, ponds in a coastal and typically rural area of northern France were surveyed for amphibians in 1974, 1992 and 2011. These repeated surveys yielded different outcomes for different species groups. Three rare species persisted in more or less specialized habitat types. Two moderately common species declined, but kept strongholds in coastal dunes and associated marshes. Five common species with broad ecological niches remained equally widespread. The Northern crested newt declined markedly and the Midwife toad declined dramatically, as did their breeding habitats in vegetated ponds and cattle drinking troughs. One species, the Moor frog, may have gone locally extinct. A model of relative resistance to amphibian dispersal was created for different landscape types, on a scale from 0 (low resistance) to 1 (high resistance). This generated values of 0.23 for pasture, 0.72 for arable and 0.98 for urban and transport. As pasture declined in the study area, while arable and urban/transport infrastructure increased, amphibian dispersal became more difficult. However, dispersal paths proved difficult to evaluate in a patchy landscape like the one surveyed, due to a paucity of spatial signal. Pond loss is a more tractable reason for the observed amphibian species decline than is the quality of intervening terrestrial habitat matrix. In 2011, 22 newly created ponds had species richness in line with pre-existing ponds and this will have counteracted a dwindling metapopulation structure, indicating that habitat creation/restoration can play a valuable role in conservation. The colonization of new ponds may also prove more informative for gauging the potential for amphibian dispersal in the landscape than the preceding decline

Investigating the great crested newt landscape in a pond rich environment : developing a landscape scale management perspective

This thesis investigated graph theoretic analysis of connectivity and habitat availability for landscape scale management of Triturus cristatus, the Great Crested Newt. The ecological foundations of wider landscape management concepts and knowledge base on T. cristatus' habitat requirements, dispersal and migration were explored. Species presence, and aquatic and terrestrial habitat on the Cholmondeley Estate, Malpas, Cheshire, UK was mapped and land cover characterized for suitability and traversibility by T. cristatus. Habitat area available and accessible from ponds were identified. Analysis and modelling of pondscape connectivity using Probability of Connectivity (PC) and related indices, was carried out using Euclidean and Cost Weighted Distance and pond clustering at ecologically relevant scales was examined. Association or correlation of presence with proximity to breeding ponds, pond cluster size, proximity and available quantity of terrestrial habitat, proximity to roads and moving water, and connectivity of breeding ponds were examined at Cost Weighted and Euclidean distances. Connectivity, (PC index), pond count in clusters at 250 and 500m thresholds of connectivity, and proximity to core habitat (broad leaved woodland and rough grassland) using Cost Weighted distances were positively associated with breeding presence. Road proximity and density, proximity of core habitat at Euclidean distances and mean inter-pond distance were not significantly associated with breeding presence. Proximity to moving water was negatively associated with breeding presence. Resistance to movement of various land cover types has important implications for habitat availability and connectivity, , / and important questions are raised in terms of "rule of thumb" guidelines for estimation of connectivity between pond populations and habitat availability around breeding ponds. Graph analysis was used to identify priority areas for maintenance of landscape level connectivity, and enhancement of habitat connectivity and availability on the local population scale, with prioritization of pond creation/protection sites against their contribution to connectivity and habitat I availability, examining various scenarios

The influence of habitat quality on demography, dispersal and population structure of great crested newts (Triturus cristatus)

The great crested newt (Triturus cristatus) is an amphibian species of European conservation concern that has suffered severe declines, primarily due to habitat loss and fragmentation. This pond-breeding amphibian lives in spatially structured populations (SSPs) where dispersal strongly influences population dynamics, genetics and thereby the long-term persistence of the whole SSP. This dissertation investigates the effects of habitat quality on demography and how such environmental as well as individual factors influence different stages of the dispersal process and consequently the population structure of great crested newts. The evaluation of a commonly used habitat suitability index (HSI) model showed no relationship between habitat quality and individual survival probability or body condition but a positive association with reproduction probability and abundance, making it a useful tool to identify habitats of higher priority for species conservation. A comprehensive analysis of dispersal and population structure combining extensive demographic and genetic data highlights the importance of habitat quality for driving context-dependent dispersal and therefore demography and genetic structure in a patchy population of great crested newts. Finally, the monitoring of 18 newly created ponds revealed that ponds were rapidly colonized, mostly over short distances, and that newts captured in new ponds were younger and tended to be larger than those in established ponds (phenotype-dependent dispersal), indicating that colonization is predominantly the result of natal dispersal by large individuals. Implications for conservation management are being discussed including corresponding recommendations.:Zusammenfassung..........1 Summary..........7 Introduction..........12 Chapter I (Linking habitat suitability to demography in a pond-breeding amphibian)..........24 Chapter II (The relationship between habitat suitability, population size and body condition in a pond-breeding amphibian)..........38 Chapter III (Context-dependent dispersal determines relatedness and genetic structure in a patchy amphibian population)..........50 Chapter IV (Pond construction for amphibian conservation: phenotypic traits influence the colonization process)..........99 Acknowledgements..........127 Author contributions..........12

Applying Conservation Genomic Techniques to Guide Management of the Reticulated Flatwoods Salamander (Ambystoma bishopi)

The Reticulated flatwoods salamander (Ambystoma bishopi) is a federally endangered amphibian endemic to the longleaf-pine ecosystem of the southeastern U.S. This study used analyses of single-nucleotide polymorphism (SNP) data, collected from 2,255 unique individuals across 5 breeding seasons, spread across the known extant range of A. bishopi, to characterize the genetic diversity and demographics of populations, genetic relationships among populations, and patterns and spatial extents of gene flow, and to evaluate potential effects of management on A. bishopi’s resiliency. Population structure was strongly hierarchical, with individual breeding ponds (n = 38) acting as semi-connected subpopulations within five regional metapopulations (Mayhaw in Georgia; Oglesby, Eastbay, Garcon, and Escribano in Florida). Likewise, gene flow among populations was scale-dependent: negligible genetic differentiation, indicative of high gene flow, was observed only between pairs of ponds separated by \u3c 0.5 km, whereas between 0.5 and 5 km I observed steep genetic isolation by distance, and beyond 5 km genetic differentiation was generally high and only weakly related to distance. Across several breeding seasons, the effective number of breeders (Nb) per pond per year averaged 26 individuals (range 4 to 104). Larger-area, slower-drying ponds located closer to other occupied ponds exhibited larger Nb and greater genetic diversity. Based on genetically-reconstructed pedigrees, the ongoing headstarting program at Escribano successfully captured 97.9% of the estimated total number of alleles, but only 63% of the total number families, in each cohort. Based on these results, I recommend the following: 1) Given its genetic distinctiveness, Georgia populations merit elevated priority for protection and restoration. 2) Resiliency and redundancy (a la the species’ recovery plan) should be assessed at the spatial grain of individual breeding ponds. 3) Attempts to restore habitat connectivity should consider dispersal over distances \u3e 500 m to be relatively unlikely. 4) Finally, to the extent that headstarted individuals are used to augment existing or introduce new populations, managers should consider the potential risks of founder effects, and reduce these risks by creating genetically and demographically diverse headstart samples, for example by maximizing the diversity of egg/larva collections over time and space within ponds

Regional Distribution, Non-invasive Detection, and Genetic Diversity of the Black-spotted Newt (Notophthalmus meridionalis)

The Black-spotted Newt (Notophthalmus meridionalis ) is one of three a salamander species native to Gulf Coast prairies of Texas and Mexico, with respective state and federal protections. This species has been neglected by the scientific community despite concerns of dramatic population declines and a globally endangered status, with the most recent work being conducted in the early 1990’s going unpublished. This study presents the most recent examination of the species providing probabilistic distribution maps, descriptions of three novel populations, assessments of surveying techniques, and the first known examination of intrapopulation genetics including the first documented genetic examination of the southern subspecies. An updated status review is provided in response to the results of this study and an expansive literature review