Population increase and changes in behavior and morphology in the Critically Endangered Redonda ground lizard (Pholidoscelis atratus) following the successful removal of alien rats and goats

Abstract

Redonda is a small volcanic Caribbean island that is home to at least 4 endemic lizard species, including the Critically Endangered ground lizard (Pholidoscelis atratus). Black rats (Rattus rattus) and domestic goats (Capra hircus) were introduced to the island at some time after its discovery by Europeans in the late 1500s. They had a devastating effect on the island, resulting in the loss of nearly all trees and most of the ground vegetation. Point count surveys of P. atratus in 2012 indicated low densities, and the invasive rats were observed hunting and preying on the lizards. Both populations of rats and goats were successfully removed in 2017 as part of an ecological restoration program, and native vegetation and invertebrate populations have increased rapidly since. Population surveys in 2017, 2018, and 2019 show the lizard population has increased by more than sixfold. In 2017, as rats and goats were being removed, we evaluated the morphology and escape behavior of this species and repeated these measurements 1 year later. We observed that P. atratus had become bolder, with a reduced flight distance. We also detected changes in limb morphology related to locomotion and suggest possible explanations that will need to be further investigated in the future. These results show how the removal of invasive species can rapidly affect lizard population recovery and behavior, potentially restoring island ecosystems to their pre-human interference dynamics.

Introduced mammals threaten the Grenadines transboundary tropical seabird hotspot

“…Addressing the threat of introduced mammals requires immediate attention to prevent extirpations at remaining seabird nesting sites, which are crucial for rebuilding decimated Caribbean populations. Eradications of introduced mammals have proven to benefit seabird colonies (Daltry et al 2012) and other native species (Knight 2018, Donihue et al 2020 globally, including in the Caribbean region.…”

Geographic Variation in Organ Size in a Toad (Duttaphrynus melanostictus)

“…Phenotypic plasticity, the ability of organisms to modify their morphological and physiological characteristics in response to diverse environmental conditions, which is important for the adaptation of species to different environmental conditions, is widely recognized across animal taxa [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. For example, the same genotype may exhibit distinct phenotypic traits as an adaptive mechanism in response to environmental fluctuations [ 20 , 21 ].…”

Geographical variation of organ size in Andrew’s toad (Bufo andrewsi)

“…The theory of phenotypic plasticity states that organisms change their morphology and physiological function as an adaptive response to environmental conditions (Stearns, 1989;Clifton et al, 2020;Peng et al, 2022). Phenotypic plasticity in morphological and physiological traits is a common phenomenon across animal taxa (Tucker and Horvath, 1973;Hammond et al, 1999;Piersma et al, 1999;Naya et al, 2009;Zhong et al, 2017;Balciauskas et al, 2020;Donihue et al, 2021;Huang et al, 2021;Liang et al, 2021;Zamora-camacho, 2021;Zedda et al, 2021;Giacomini et al, 2022;Hinds et al, 2022). Organ's size can reflect the traits of structures with certain morphology and independent physiological functions within an organism, and it' variation also Zhu et al 10.3389/fevo.2022.972942 undergo certain adaptations to respond to environmental changes (Hammond et al, 2001;Chen et al, 2021;Jiang et al, 2022a).…”