Assessment and validation of miniaturized technology for the remote tracking of critically endangered Galápagos pink land iguana (Conolophus marthae)

Abstract Background: Gathering ecological data for species of conservation concern inhabiting remote regions can be daunting and, sometimes, logistically infeasible. We built a custom-made GPS tracking device that allows to remotely and accurately collect animal position, environmental, and ecological data, including animal temperature and UVB radiation. We designed the device to track the critically endangered Galápagos pink land iguana, Conolophus marthae. Here we illustrate some technical solutions adopted to respond to challenges associated with such task and present some preliminary results from controlled trial experiments and field implementation. Results: Our tests show that estimates of temperature and UVB radiation are affected by the design of our device, in particular by its casing. The introduced bias, though, is systematic and can be corrected using linear and quadratic regressions on collected values. Our data show that GPS accuracy loss, although introduced by vegetation and orientation of the devices when attached to the animals, is acceptable, leading to an average error gap of less than 15 m in more than 50% of the cases. Conclusions: We address some technical challenges related to the design, construction, and operation of a custommade GPS tracking device to collect data on animals in the wild. Systematic bias introduced by the technological implementation of the device exists. Understanding the nature of the bias is crucial to provide correction models. Although designed to track land iguanas, our device could be used in other circumstances and is particularly useful to track organisms inhabiting locations that are difficult to reach or for which classic telemetry approaches are unattainable

All is fish that comes to the net: metabarcoding for rapid fisheries catch assessment

Monitoring marine resource exploitation is a key activity in fisheries science and biodiversity conservation. Since research surveys are time‐consuming and costly, fishery‐dependent data (i.e. derived directly from fishing vessels) are increasingly credited with a key role in expanding the reach of ocean monitoring. Fishing vessels may be seen as widely ranging data‐collecting platforms, which could act as a fleet of sentinels for monitoring marine life, in particular exploited stocks. Here, we investigate the possibility of assessing catch composition of single hauls carried out by trawlers by applying DNA metabarcoding to the dense water draining from fishing nets just after the end of hauling operations (hereafter ‘slush’). We assess the performance of this approach in portraying β‐diversity and examining the quantitative relationship between species abundances in the catch and DNA amount in the slush (read counts generated by amplicon sequencing). We demonstrate that the assemblages identified using DNA in the slush satisfactorily mirror those returned by visual inspection of net content (about 71% of species and 86% of families of fish) and detect a strong relationship between read counts and species abundances in the catch. We therefore argue that this approach could be upscaled to serve as a powerful source of information on the structure of demersal assemblages and the impact of fisheries

Wolfram Syndrome: New Mutations, Different Phenotype

BACKGROUND: Wolfram Syndrome (WS) is an autosomal recessive neurodegenerative disorder characterized by Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness identified by the acronym "DIDMOAD". The WS gene, WFS1, encodes a transmembrane protein called Wolframin, which recent evidence suggests may serve as a novel endoplasmic reticulum calcium channel in pancreatic β-cells and neurons. WS is a rare disease, with an estimated prevalence of 1/550.000 children, with a carrier frequency of 1/354. The aim of our study was to determine the genotype of WS patients in order to establish a genotype/phenotype correlation. METHODOLOGY/PRINCIPAL FINDINGS: We clinically evaluated 9 young patients from 9 unrelated families (6 males, 3 females). Basic criteria for WS clinical diagnosis were coexistence of insulin-treated diabetes mellitus and optic atrophy occurring before 15 years of age. Genetic analysis for WFS1 was performed by direct sequencing. Molecular sequencing revealed 5 heterozygous compound and 3 homozygous mutations. All of them were located in exon 8, except one in exon 4. In one proband only an heterozygous mutation (A684V) was found. Two new variants c.2663 C>A and c.1381 A>C were detected. CONCLUSIONS/SIGNIFICANCE: Our study increases the spectrum of WFS1 mutations with two novel variants. The male patient carrying the compound mutation [c.1060_1062delTTC]+[c.2663 C>A] showed the most severe phenotype: diabetes mellitus, optic atrophy (visual acuity 5/10), deafness with deep auditory bilaterally 8000 Hz, diabetes insipidus associated to reduced volume of posterior pituitary and pons. He died in bed at the age of 13 years. The other patient carrying the compound mutation [c.409_424dup16]+[c.1381 A>C] showed a less severe phenotype (DM, OA)

Natural Population Dynamics of Rock Iguanas in the Bahama Archipelago

Understanding whether groups of individuals represent a single panmictic gene pool, or multiple genetically structured populations across a species range should aid in predicting whether specific conservation strategies would be more or less effective for species preservation. Further, contrasting the population structures of multiple coexisting taxa could foster an even deeper understanding of evolutionary divergence among demes and potentially even suggest local adaptation in the form of tight coevolutionary relationships. Finally, the analysis of population dynamics within small and isolated populations could improve our understanding of the relative importance that different evolutionary mechanisms have in predicting population persistence in the wild. Using microsatellite markers I characterized the population genetic structure in the critically endangered Cyclura cychlura cychlura iguanas on Andros Island. I found significant differences between inferred and realized rates of gene flow. This finding demonstrates that evolutionarily independent populations can occur even with high rates of dispersal. In the second and third study I contrasted patterns of genetic variability in Cyclura cychlura cychlura iguanas, ticks in the genus Amblyomma parasitizing these iguanas, and Rickettsia spp., potential pathogens transmitted by these ticks. I determined that genetic differences among Rickettsia samples and Amblyomma samples are highly concordant with genetic divergence among iguana populations. This finding suggests largely vertical dispersal of ticks and their super-parasite, a high specificity of this reptile-tick interaction, and historically low rates of dispersal in iguanas. This finding also indicates that island populations of iguanas may be locally adapted due to tight coevolutionary relationships. Finally, I investigated the mechanisms that eliminate harmful mutations in small isolated and natural populations of the critically endangered Cyclura cychlura cychlura iguanas. Using molecular tools I found indirect evidence suggesting that small natural populations can maintain significant levels of genetic variation in spite of strong selection acting against harmful mutations. Under regimes of random mating, the buildup of harmful mutations in small populations may result in a large number of inviable young. However, harmful mutations may also be eliminated when exposed to natural selection through increased competition, as population density increases. However, quantification of the relative role of competition was not feasible in this study

Turks and Caicos rock iguana (Cyclura carinata) : conservation and management plan 2020–2024

The Endangered Turks and Caicos rock iguana, Cyclura carinata, is found only on the islands and cays of Turks and Caicos Islands (TCI), and on Booby Cay in The Bahamas, northwest of Providenciales. These iguanas now occupy less than 10 percent of their historic range largely due to the impact of invasive mammalian predators. Although conservation efforts have led to stabilisation of the population resulting in the 2020 down-listing of this species from Critically Endangered to Endangered on the IUCN Red List of Threatened Species, threats persist and management efforts are needed. This document presents a comprehensive four-year plan for the conservation and management actions considered essential to ensuring the long-term survival of Cyclura carinata in the wild. This document combines knowledge and expertise from local government, local and international NGOs, the tourism industry, educators, homeowners, private island managers, civil society, and members of the IUCN SSC Iguana Specialist Group working in the TCI

Ophthalmic segment of internal carotid artery aneurysm mimicking normal tension glaucoma.

Abstract A 41-year-old caucasian male was referred to the Glaucoma clinic at our tertiary referral centre with a diagnosis of normal tension glaucoma after the finding of increased bilateral asymmetrical cup/disc ratios, with normal intraocular pressures. On examination, the authors confirmed the presence of bilateral reduced optic disc rims alongside a left pale residual rim, and a further discovered a positive dyschromatopsia with a bilateral visual field alteration. The left visual field showed a relative scotoma confined to the vertical midline. After initiating investigation for suspected glaucoma, the authors ordered a magnetic resonance imaging that evidenced an internal carotid aneurysm along the ophthalmic segment, stretching across the optic chiasm with a major involvement of the left optic nerve and partial involvement of the right optic nerve. Aneurysm embolisation was performed with complete resolution of signs and symptoms achieved 5 months post-operatively. Despite glaucoma being the most frequent condition causing optic disc atrophy and visual field loss, it is not the only cause. Any atypical visual field defect not in keeping with a glaucomatous field loss should be further investigated. The ophthalmologist should thoroughly assess all signs that could lead to different diagnosis

Genetic structure of Rhinoceros Rock Iguanas, Cyclura cornuta, in the Dominican Republic, with insights into the impact of captive facilities and the taxonomic status of Cyclura on Mona Island

Hispaniola is the second largest island in the Caribbean and harbors an extensive amount of biodiversity. The geologic history and resulting complex topography of the island has led to significant differentiation across various taxonomic groups. Hispaniola is the only Caribbean Island with two species of Rock Iguanas, genusCyclura. Rhinoceros Rock Iguanas (C. cornuta) are wide-ranging across Hispaniola, occurring in isolated pockets, primarily in low elevation xeric areas. To better understand the population structure of this species, we used a combination of mtDNA and nuclear markers to elucidate the genetic variation of wild populations across 13 sampling regions in the Dominican Republic (DR), as well as neighboring Mona Island, home to aCyclurapopulation of uncertain taxonomic status. Further, we evaluate the origin of iguanas in captive facilities throughout the DR. Our data reveal a high degree of genetic diversity across wild populations within the DR and shed light on the taxonomic status of the Mona island population. Further, novel genetic diversity is found in captive facilities, most likely resulting from interbreeding between individuals from genetically distinct populations within the captive facilities. Our results suggest that the captive facilities may pose a threat to wild populations and increased regulation of these facilities is needed

Inferred vs realized patterns of gene flow: an analysis of population structure in the Andros Island Rock Iguana.

Ecological data, the primary source of information on patterns and rates of migration, can be integrated with genetic data to more accurately describe the realized connectivity between geographically isolated demes. In this paper we implement this approach and discuss its implications for managing populations of the endangered Andros Island Rock Iguana, Cyclura cychlura cychlura. This iguana is endemic to Andros, a highly fragmented landmass of large islands and smaller cays. Field observations suggest that geographically isolated demes were panmictic due to high, inferred rates of gene flow. We expand on these observations using 16 polymorphic microsatellites to investigate the genetic structure and rates of gene flow from 188 Andros Iguanas collected across 23 island sites. Bayesian clustering of specimens assigned individuals to three distinct genotypic clusters. An analysis of molecular variance (AMOVA) indicates that allele frequency differences are responsible for a significant portion of the genetic variance across the three defined clusters (Fst = 0.117, p\u3c0.01). These clusters are associated with larger islands and satellite cays isolated by broad water channels with strong currents. These findings imply that broad water channels present greater obstacles to gene flow than was inferred from field observation alone. Additionally, rates of gene flow were indirectly estimated using BAYESASS 3.0. The proportion of individuals originating from within each identified cluster varied from 94.5 to 98.7%, providing further support for local isolation. Our assessment reveals a major disparity between inferred and realized gene flow. We discuss our results in a conservation perspective for species inhabiting highly fragmented landscapes

Genetic diversity and structure in the Endangered Allen Cays Rock Iguana, Cyclura cychlura inornata

The Endangered Allen Cays Rock Iguana (Cyclura cychlura inornata) is endemic to the Allen Cays, a tiny cluster of islands in the Bahamas. Naturally occurring populations exist on only two cays (<4 ha each). However, populations of unknown origin were recently discovered on four additional cays. To investigate patterns of genetic variation among these populations, we analyzed nuclear and mitochondrial markers for 268 individuals. Analysis of three mitochondrial gene regions (2,328 bp) and data for eight nuclear microsatellite loci indicated low genetic diversity overall. Estimates of effective population sizes based on multilocus genotypes were also extremely low. Despite low diversity, significant population structuring and variation in genetic diversity measures were detected among cays. Genetic data confirm the source population for an experimentally translocated population while raising concerns regarding other, unauthorized, translocations. Reduced heterozygosity is consistent with a documented historical population decline due to overharvest. This study provides the first range-wide genetic analysis of this subspecies. We suggest strategies to maximize genetic diversity during ongoing recovery including additional translocations to establish assurance populations and additional protective measures for the two remaining natural populations