Rapid morphological change in a small mammal species after habitat fragmentation over the past half‐century

Abstract

AimTo compare the rapid shifts in body size of mainland and island populations of a native rodent and examine the mechanisms underlying these changes.LocationThousand Island Lake, China, which was created in 1959 when the Xin'anjiang Dam was constructed for generating hydroelectricity.TaxonThe Chinese white‐bellied rat,Niviventer confucianus.MethodsField surveys were conducted from 2015 to 2018 to collect data on body size of the rodents from a set of islands and nearby mainland sites. We constructed multiple linear models to examine the relationships between body size (length and mass) of rodents and biological variables (predators, competitors and food availability). We also conducted structural equation modelling (SEM) by constructing models via confirmatory path analysis.ResultsAll island populations ofN.confucianushad significantly larger body size (both body mass and body length) than their mainland counterparts. Moreover, populations on small and more isolated islands had larger body size than their relatives on big islands. The relative absence of predators (large‐bodied mammals, snakes and raptors) on islands was most strongly associated with shifts in the body size of rodents. The documented changes occurred after only a half‐century of fragmentation.Main conclusionsThe observed rapid body enlargement of rodents after habitat fragmentation is consistent with a release from predation pressure. SEM indicated that island area, rather than island isolation, had positive effects on the abundance of predators, interspecific competitors and food resources, which then had an indirect impact on body size of the rodents. In this study, we report a remarkably rapid case of mammal morphological shifts in a small mammal in response to habitat fragmentation. Given the omnipresence of dams and other anthropogenic disturbances, our findings suggest that a wave of rapid phenotypic shifts in terrestrial vertebrates is taking place in the Anthropocene.

Sex‐specific shifts in morphology and diet in a frog after 50 years of anthropogenic habitat fragmentation

“…The sampling effort was sufficient to measure the species richness of predators as demonstrated by species accumulation curves in the above references. Overall, the data showed that there is a higher predator species richness on the mainland than on islands, and this pattern has also been reinforced by a recent study, which included snakes, carnivorous mammals and birds (Li et al, 2021).…”

“…The species richness of snakes was based on previously published data (Li et al, 2021; Wang, Wang, & Ding, 2012b) and a recent survey during the breeding season between April to July from 2009–2013. We surveyed snakes on islands and mainland sites 30 times in total (15 times in daytime and 15 times at night) to detect as many species as possible, as snake species differed in their diurnal and nocturnal activity periods (Wang et al, 2015).…”

“…Carnivores and small mammals were monitored by using camera traps combined with live traps from 2011 to 2014 and from 2015 to 2017 for both islands and mainland sites (Li et al, 2021; Xu et al, 2014; Zeng et al, 2019). The camera trap photos and rodents were identified as species by professional researchers from our laboratory and rodents were released after measurements.…”

A systematic literature review on the forest health biomonitoring technique: A decade of practice, progress, and challenge

“…Animals also have the ability to change morphological characteristics such as their skin color, body parts size, etc. However, according to Li et al (2021), changes in morphological characteristics of animals take a long time to happen and, in terms of monitoring forest health, this is only practical for long term monitoring.…”

The skull variation of the olive field mouseAbrothrix olivacea(Cricetidae: Abrotrichini) is localized and correlated to the ecogeographic features of its geographic distribution

“…In general, studies directed to parsing this interaction first characterize both, the variation in shape and size of morphological structures, and then these are statistically correlated to the variability of different climatical ( e.g ., temperature, precipitation, humidity) and habitat physiognomy aspects ( e.g ., land cover, vegetation coverture, primary productivity; Sikes & Kennedy, 1992 ; Yom-Tov & Yom-Tov, 2004 ; Wolf, Friggens & Salazar-Bravo, 2009 ; McNab, 2010 ; Marchan-Rivadeneira et al, 2012 ; García-Mendoza et al, 2018 ; Ariosa-Olea & Mancina, 2018 ). Few other studies have also considered aspects, such as insularity (see Li et al (2021) for a recent assessment on this topic), as potential drivers of phenotypic change. Assessment such as these have demonstrated that morphological variation is seldom homogenous across regions with disparate habitats and/or climates; instead, this component of the intraspecific variation is usually structured according to the pattern of variation of one or several of the environmental aspects scrutinized (see Blackburn & Gaston, 1994 ; Gaston, Chown & Evans, 2008 ).…”