Changing invaders: trends of gigantism in insular introduced rats

Geer, Alexandra van der

doi:10.1017/s0376892918000085

Cited by 15 publications

(7 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rats generally reach a larger size on tropical islands in view of the known island rule ecological hypothesis, which negatively correlates body size to co-occurring mammalian species; for instance, Pacific islands have recorded gigantism in the invasive rodent Rattus exulans [54]. Although not significantly different, size differences between males and females were observed and may be related to the natural attribute of sexual dimorphism [44].…”

Section: Rattus Characteristics In Relation To Infection Ratesmentioning

confidence: 99%

Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

Biscornet

Révillion²,

Jégo³

et al. 2021

Remote Sensing

View full text Add to dashboard Cite

Leptospirosis, an environmental infectious disease of bacterial origin, is the infectious disease with the highest associated mortality in Seychelles. In small island territories, the occurrence of the disease is spatially heterogeneous and a better understanding of the environmental factors that contribute to the presence of the bacteria would help implement targeted control. The present study aimed at identifying the main environmental parameters correlated with animal reservoirs distribution and Leptospira infection in order to delineate habitats with highest prevalence. We used a previously published dataset produced from a large collection of rodents trapped during the dry and wet seasons in most habitats of Mahé, the main island of Seychelles. A land use/land cover analysis was realized in order to describe the various environments using SPOT-5 images by remote sensing (object-based image analysis). At each sampling site, landscape indices were calculated and combined with other geographical parameters together with rainfall records to be used in a multivariate statistical analysis. Several environmental factors were found to be associated with the carriage of leptospires in Rattus rattus and Rattus norvegicus, namely low elevations, fragmented landscapes, the proximity of urbanized areas, an increased distance from forests and, above all, increased precipitation in the three months preceding trapping. The analysis indicated that Leptospira renal carriage could be predicted using the species identification and a description of landscape fragmentation and rainfall, with infection prevalence being positively correlated with these two environmental variables. This model may help decision makers in implementing policies affecting urban landscapes and/or in balancing conservation efforts when designing pest control strategies that should also aim at reducing human contact with Leptospira-laden rats while limiting their impact on the autochthonous fauna.

show abstract

Section: Rattus Characteristics In Relation To Infection Ratesmentioning

confidence: 99%

Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

Biscornet

Révillion²,

Jégo³

et al. 2021

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…We foresee that, under global change, the extinction of insular species and the introduction of novel (invasive) species may trigger new equilibria, with concomitant shifts in the composition of insular communities and the opening of novel niches to which species may respond via genetic adaptations and phenotypic plasticity. Recent evidence indicates that even introduced species on islands, which were not included in our analysis, predictably evolve towards dwarfism or gigantism [67][68][69] . In theory, as the Anthropocene gathers pace, further extinctions will drive a decline in the mean body size of the overall island community, pushing optimal body sizes towards the lower end of body size ranges in the different vertebrate groups.…”

Section: Body Size Evolution In Extinct Speciesmentioning

confidence: 99%

The island rule explains consistent patterns of body size evolution in terrestrial vertebrates

Benítez‐López

Santini

Gallego‐Zamorano

et al. 2020

Preprint

View full text Add to dashboard Cite

Island faunas can be characterized by gigantism in small animals and dwarfism in large animals, but the extent to which this so-called ‘island rule’ provides a general explanation for evolutionary trajectories on islands remains contentious. Here we develop phylogenetic models to assess patterns and drivers of body size evolution across a global sample of paired island-mainland populations of terrestrial vertebrates. We show that ‘island rule’ effects are widespread in mammals, birds and reptiles, but less evident in amphibians, which mostly tend towards gigantism. We also found that the magnitude of insular dwarfism and gigantism is mediated by climate as well as island size and isolation, with more pronounced effects in smaller, more remote islands for mammal and reptiles. We conclude that the island rule is pervasive across vertebrates, but that the implications for body size evolution are nuanced and depend on an array of context-dependent ecological pressures and environmental conditions.

show abstract

“…Because the differences in the vagility and adaptive local response of both species, we expect to find higher levels of morphological differentiation along the Patagonian range in A. olivacea with respect to O. longicaudatus. Additionally, we expect to find evidence of an eventual cranial size increment of insular individuals (the Island Rule) compared to mainland conspecifics, as it has been observed in other small rodents distributed in archipelagomainland systems [31].…”

Section: Introductionmentioning

confidence: 68%

Morphological variation in two sigmodontine rodents along the mainland and the Fuegian archipelago in Chilean southern Patagonia

Valladares-Gómez

Huenumilla-Linares

Rodríguez‐Serrano

et al. 2020

Rev. Chil. de Hist. Nat.

View full text Add to dashboard Cite

Background: Analysis of morphological variation in archipelagos has been essential to understand the evolution of terrestrial vertebrates. In particular, these natural scenarios allow to assess morphological changes experienced by insular fauna compared to their mainland counterparts. In mammals, morphological changes of insular forms have been observed in size and shape of body and cranial traits. The southern Patagonia of Chile represents a unique scenario to analyze morphological variation in two of the most widely distributed small rodents along western southern South America: Abrothrix olivacea and Oligoryzomys longicaudatus. Methods: We applied linear and three-dimensional geometric morphometric tools to analyze the variation in cranial morphology of A. olivacea (N = 80) and O. longicaudatus (N = 49). Sampled localities were distributed in the mainland and islands of the Fuegian archipelago in Chilean Patagonia. Standard multivariate methods, as Principal Components Analysis, and Logistic Regression models were carried out to evaluate differences in size and shape of crania. Results: We detected higher levels of morphological variation in the crania of A. olivacea if compared to O. longicaudatus. The variation was associated to cranial size instead of shape. We observed significant differences between insular and mainland individuals in A. olivacea, being the cranium size of this species significantly bigger on islands. Indeed, specimens of A. olivacea from "Isla Wellington", exhibited the higher increment in cranium size compared to any other mainland and insular site sampled for this species. In contrast, insular and mainland forms of O. longicaudatus did not show significant differences in cranial morphology. Conclusions: We suggest that the patterns of morphological variation observed in these two small rodents along Patagonia, could be explained in terms of the historical biogeography of the region, and the different ecological features of the studied species.

show abstract

Changing invaders: trends of gigantism in insular introduced rats

Abstract: SUMMARYThe degree and direction of morphological change in invasive species with a long history of introduction are insufficiently known for a larger scale than the archipelago or island group.

Cited by 15 publications

References 56 publications

Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

The island rule explains consistent patterns of body size evolution in terrestrial vertebrates

Morphological variation in two sigmodontine rodents along the mainland and the Fuegian archipelago in Chilean southern Patagonia

Contact Info

Product

Resources

About