Giant tortoises spread to western Indian Ocean islands by sea drift in pre‐Holocene times, not by later human agency – response to Wilmé <i>et al</i>. (2016a)

Cheke, Anthony S.; Pedrono, Miguel; Bour, Roger; Anderson, Atholl; Griffiths, Christine; Iverson, John B.; Hume, Julian P.; Walsh, Martin

doi:10.1111/jbi.12882

Cited by 12 publications

(11 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Europe and Asia, where freshwater turtles are recorded occupying brackish water in several studies, geographic ranges of turtles may have expanded or shifted more recently in the late Pleistocene–Holocene (Kukushkin & Jablonski, ), leaving isolated relict populations in either freshwater or brackish water environments. In addition, some freshwater turtle species and tortoises are capable of long‐distance transoceanic dispersal (Gerlach, Muir, & Richmond, ; Vamberger et al, ; Cheke et al, ), whereas others have been dispersed by humans. Thus, ranges may have shifted more recently into saline environments, generating contemporary brackish water records (Kukushkin & Jablonski, ).…”

Section: Resultsmentioning

confidence: 99%

Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise

et al. 2018

View full text Add to dashboard Cite

The projected rise in global mean sea levels places many freshwater turtle species at risk of saltwater intrusion into freshwater habitats. Freshwater turtles are disproportionately more threatened than other taxa; thus, understanding the role of salinity in determining their contemporary distribution and evolution should be a research priority. Freshwater turtles are a slowly evolving lineage; however, they can adapt physiologically or behaviourally to various levels of salinity and, therefore, temporarily occur in marine or brackish environments. Here, we provide the first comprehensive global review on freshwater turtle use and tolerance of brackish water ecosystems. We link together current knowledge of geographic occurrence, salinity tolerance, phylogenetic relationships, and physiological and behavioural mechanisms to generate a baseline understanding of the response of freshwater turtles to changing saline environments. We also review the potential origins of salinity tolerance in freshwater turtles. Finally, we integrate 2100 sea level rise (SLR) projections, species distribution maps, literature gathered on brackish water use, and a phylogeny to predict the exposure of freshwater turtles to projected SLR globally. From our synthesis of published literature and available data, we build a framework for spatial and phylogenetic conservation prioritization of coastal freshwater turtles. Based on our literature review, 70 species (∼30% of coastal freshwater turtle species) from 10 of the 11 freshwater turtle families have been reported in brackish water ecosystems. Most anecdotal records, observations, and descriptions do not imply long-term salinity tolerance among freshwater turtles. Rather, experiments show that some species exhibit potential for adaptation and plasticity in physiological, behavioural, and life-history traits that enable them to endure varying periods (e.g. days or months) and levels of saltwater exposure. Species that specialize on brackish water habitats are likely to be vulnerable to SLR because of their exclusive coastal distributions and adaptations to a narrow range of salinities. Most species, however, have not been documented in brackish water habitats but may also be highly vulnerable to projected SLR. Our analysis suggests that approximately 90% of coastal freshwater turtle species assessed in our study will be affected by a 1-m increase in global mean SLR by 2100. Most at risk are freshwater turtles found in New Guinea, Southeast Asia, Australia, and North and South America that may lose more than 10% of their present geographic range. In addition, turtle species in the families Chelidae, Emydidae, and Trionychidae may experience the greatest exposure to projected SLR in their present geographic ranges. Better understanding of survival, growth, reproductive and population-level responses to SLR will improve region-specific population viability predictions of freshwater turtles that are increasingly exposed to SLR. Integrating phylogenetic, physiological, and spatial frameworks t...

show abstract

Section: Resultsmentioning

confidence: 99%

Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise

et al. 2018

View full text Add to dashboard Cite

show abstract

“…However, hunting was the key driver. Extensive archaeological bone middens and historic records show that this was the case with birds c. >4 kg in New Zealand (Duncan et al 2002; Worthy & Holdaway 2002; Roff & Roff 2003; Perry et al 2014), and similarly with large birds and reptiles of Indian (Cheke & Bour 2014) and Pacific Ocean islands (e.g. Steadman et al 2002).…”

Section: Holocene Anthropogenic Drivers Of Extinctions On Islandsmentioning

confidence: 97%

Island extinctions: processes, patterns, and potential for ecosystem restoration

et al. 2017

Self Cite

View full text Add to dashboard Cite

SUMMARYExtinctions have altered island ecosystems throughout the late Quaternary. Here, we review the main historic drivers of extinctions on islands, patterns in extinction chronologies between islands, and the potential for restoring ecosystems through reintroducing extirpated species. While some extinctions have been caused by climatic and environmental change, most have been caused by anthropogenic impacts. We propose a general model to describe patterns in these anthropogenic island extinctions. Hunting, habitat loss and the introduction of invasive predators accompanied prehistoric settlement and caused declines of endemic island species. Later settlement by European colonists brought further land development, a different suite of predators and new drivers, leading to more extinctions. Extinctions alter ecological networks, causing ripple effects for islands through the loss of ecosystem processes, functions and interactions between species. Reintroduction of extirpated species can help restore ecosystem function and processes, and can be guided by palaeoecology. However, reintroduction projects must also consider the cultural, social and economic needs of humans now inhabiting the islands and ensure resilience against future environmental and climate change.

show abstract

“…indica ; up to 120 cm) 4 . Recently, it has been proposed that the Mascarene giant tortoises were introduced by early Austronesian sailors 5 , spurring a series of hefty rebuttals 6–9 . Short mitochondrial DNA (mtDNA) sequences of approximately 400 bp length produced in a pioneering ancient DNA (aDNA) study 20 years ago 10 played a key role in the arguments against the human-mediated arrival of giant tortoises, as this genetic data set clearly shows the distinctiveness of Mascarene tortoises.…”

Section: Introductionmentioning

confidence: 99%

Ancient mitogenomics clarifies radiation of extinct Mascarene giant tortoises (Cylindraspis spp.)

Kehlmaier

Graciá

Campbell

et al. 2019

Sci Rep

View full text Add to dashboard Cite

The five extinct giant tortoises of the genus Cylindraspis belong to the most iconic species of the enigmatic fauna of the Mascarene Islands that went largely extinct after the discovery of the islands. To resolve the phylogeny and biogeography of Cylindraspis, we analysed a data set of 45 mitogenomes that includes all lineages of extant tortoises and eight near-complete sequences of all Mascarene species extracted from historic and subfossil material. Cylindraspis is an ancient lineage that diverged as early as the late Eocene. Diversification of Cylindraspis commenced in the mid-Oligocene, long before the formation of the Mascarene Islands. This rejects any notion suggesting that the group either arrived from nearby or distant continents over the course of the last millions of years or had even been translocated to the islands by humans. Instead, Cylindraspis likely originated on now submerged islands of the Réunion Hotspot and utilized these to island hop to reach the Mascarenes. The final diversification took place both before and after the arrival on the Mascarenes. With Cylindraspis a deeply divergent clade of tortoises became extinct that evolved long before the dodo or the Rodrigues solitaire, two other charismatic species of the lost Mascarene fauna.

show abstract

Giant tortoises spread to western Indian Ocean islands by sea drift in pre‐Holocene times, not by later human agency – response to Wilmé et al. (2016a)

Abstract: Evidence from DNA phylogeny, Plio-Pleistocene ocean currents, giant tortoise dispersal, evolution of plant defences, radiocarbon dates and archaeology indicates that the endemic giant tortoises on the Mascarenes and Seychelles colonized naturally and were not translocated there by humans.

Cited by 12 publications

References 31 publications

Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise

Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise

Island extinctions: processes, patterns, and potential for ecosystem restoration

Ancient mitogenomics clarifies radiation of extinct Mascarene giant tortoises (Cylindraspis spp.)

Contact Info

Product

Resources

About