Dances with wolves: The demographic consequence of asymmetric competition and intraguild predation in a native-invasive skink system
Journal
Functional Ecology
Journal Volume
37
Journal Issue
3
Start Page
614
ISSN
0269-8463
Date Issued
2023-03-01
Author(s)
Huang, Shi Ping
Liao, Chen Pan
Hsu, Jung Ya
Tsai, Jing Fu
Liu, Shao Lun
Huang, Wen San
Abstract
Currently, we lack enough knowledge to fully explain how the impacts of species invasion on native communities are attributed to multifaceted, individual-based behavioural outcomes. Here, we illustrate the long-term population dynamics of the native long-tailed sun skink (Eutropis longicaudata) before and after the invasion of the common sun skink (Eutropis multifasciata). We conducted diet investigation, morphological measurement, and a series of behavioural experiments both in the field and laboratory. We explained how the impacts of the invasive skink on the native skink can cascade towards the population level based on these individual-level behavioural data. We present evidence of competition exclusion of the native skink population resulting from the invasion of the common sun skink. The drastic decline found in the native skink population was largely accounted for by low recruitment, as shown by the decrease in its clutch numbers correspondingly. We also found dominance of the invasive skink in both exploitation competition and intraguild predation. Considering the highly overlapping morphological and dietary niches between the two species, our findings imply that the native skink has undergone strong food competition and predation pressure on its eggs and juveniles. Interestingly, the native skink started to display parental care behaviour 2 years after the invasion event, and its clutch survival rate has recovered since then. The shift in parental care behaviour may help the native skink cope with this new predation pressure from the invasive skink. Overall, the two competitive skinks showed low chances of coexisting. The negative population growth of this native skink species may be primarily derived from poor reproductive performance, given a sharp decline in its clutch numbers and its inferiority in exploitation competition, despite rebounding clutch survival rates. Read the free Plain Language Summary for this article on the Journal blog. © 2023 The Authors. Functional Ecology © 2023 British Ecological Society.
Subjects
behaviour plasticity
competition exclusion
demographic consequences
niche overlap
species invasion
Publisher
British Ecological Society
Type
journal article