Going underground: short- and long-term movements may reveal the fossorial spatial ecology of an amphisbaenian

Abstract

Background The movement and spatial ecology of an animal depends on its morphological and functional adaptations to its environment. In fossorial animals, adaptations to the underground life help to face peculiar ecological challenges, very different from those of epigeal species, but may constrain their movement ability. Methods We made a long-term capture-recapture study of the strictly fossorial amphisbaenian reptile Trogonophis wiegmanni to analyze its long-term movement patterns. We also used passive integrated transponder (PIT) telemetry to detect and follow undisturbed individuals underground, obtaining data of their short-term movement patterns. Results Amphisbaenians showed a high site fidelity, moving short distances and over small areas, and spending some days without any noticeable movement, even under favorable conditions. We also found differences in movements between sexes and age classes. Conclusions This movement and spatial strategy can be related to the energetic constrains of underground burrowing, or to the low metabolic requirements of fossorial reptiles, as distances and areas covered were much smaller than for epigeal reptiles of similar size. Individual differences probably reflect differential reproductive and social requirements of males and females, and that younger individuals might show more floating behavior until they can settle in a territory. This study is a rare example describing the movement ecology of a fossorial species and may contribute to the general understanding of the factors that affect space use and movement decisions in animals.

Soil pollution by heavy metals correlates with levels of faecal glucocorticoid metabolites of a fossorial amphisbaenian reptile

“…This was justified because soil characteristics were very similarly homogeneous in an area of such dimensions surrounding the soil sampling point, and because amphisbaenians have a high site fidelity and move over very small areas (approx. between 1 and 25 m 2 ; Martín et al , 2021b ). Therefore, we considered that each soil sampling point reflected the soil environment long-term experienced by one individual captured in that area.…”

“…The amphisbaenian T. wiegmanni is a Northwest African species found from Morocco to northeast Tunisia ( Bons and Geniez, 1996 ). Similarly to other amphisbaenians, the knowledge of its ecology is limited, but there are increasing knowledge on its habitat use ( Civantos et al , 2003 ; Martín et al , 2013a , 2021a ), diet and prey detection ( Bons and Saint Girons, 1963 ; Martín et al , 2013b ; López et al , 2014 ; Baeckens et al , 2017 ), thermal biology ( Gatten and McClung, 1981 ; López et al , 2002 ), reproduction ( Bons and Saint Girons, 1963 ) and population and social biology ( Martín et al , 2011a , b , 2012 , 2020 , 2021b ). This species is listed as of ‘Least Concern’ by the IUCN in view of its wide distribution and ‘presumed’ large population ( Mateo et al , 2009 ).…”

“…Research of fossorial animals is, however, important because they face different ecological challenges and threats than epigeal species and have evolved very peculiar adaptations to the underground life ( Gans, 1974 , 1978 ). Moreover, fossorial species may be at particular risk of extinction because their low dispersal ability ( Martín et al , 2021b ) may preclude them to avoid local soil disturbances. Ignorance of these effects may result in a bad conservation state that may be going unnoticed ( How and Shine, 1999 ; Decaens et al , 2006 ; Measey et al , 2009 ).…”

“…Amphisbaenians have very specialized morphological and functional adaptations to a fossorial life, such as reduced vision, elongated body or loss of limbs ( Gans, 1978 , 2005 ; Navas et al , 2004 ), which, however, constrain many other aspects of their ecology, such as habitat or diet selection or some reproductive parameters ( Papenfuss, 1982 ; Colli and Zamboni, 1999 ; Webb et al , 2000 ; Andrade et al , 2006 ; Gomes et al , 2009 ). Because amphisbaenians spent all their lives underground and often show high site fidelity ( Martín et al , 2021b ), they must be especially affected by any soil alteration. In fact, natural and anthropogenic soil alterations seem to affect the body condition of amphisbaenians ( Martín et al , 2015 , 2017 ).…”

Relationships between soil pollution by heavy metals and melanin‐dependent coloration of a fossorial amphisbaenian reptile

“…Here, to test the "industrial melanism" hypothesis (Chatelain et al 2014;Goiran et al 2017), we designed a field study in island populations of T. wiegmanni amphisbaenians. In some areas of the study populations, nesting seagull colonies are known to increase heavy metal concentration in the soil (García et al 2002a, b;Martín et al 2015), and it is plausible that metals could reach amphisbaenians through their soil invertebrate prey (Martín et al 2013b). We specifically examined 1) whether this amphisbaenian is able to eliminate the heavy metals contaminants of its body through sloughing its skin, and 2) whether increased melanin-dependent dark coloration may facilitate this detoxifying mechanism.…”