The Culprit behind the Mass Death of Mangroves: Egrets or Rats (Rattus losea)?

Abstract

Mangroves play a crucial role in maintaining coastal ecological balance. This study focused on the impact of branch-breaking behavior on the mortality of Rhizophora stylosa in the Guangxi Shankou Mangrove Reserve. However, we found mangrove mortality in areas devoid of egret habitation, prompting a reevaluation of our research hypothesis. Further investigation suggested that nesting behavior was the primary cause of mangrove mortality. A comparison of the data from areas with egrets (Egretta garzetta, Ardea intermedia) and lesser rice-field rats (Rattus losea) activity indicated significant mechanical damage caused by rats to mangroves as the main cause of mortality. Additionally, we found that the biological characteristics of R. stylosa, particularly its stunted growth and recovery abilities after branch breaking, were key factors affecting its survival. These findings imply that rat-induced mortality may not occur in other less susceptible mangrove species. The results contradict assumptions regarding the impact of egret behavior and highlight the importance of the biological characteristics of R. stylosa. This offers fresh insights into mangrove conservation and management, emphasizing the need for ongoing observation and hypotheses verification. Future studies should explore the influence of lesser rice-field rats’ activity and the intrinsic characteristics of R. stylosa on the ecosystem’s long-term stability.