Ecological Resilience in Isolated Biomes
Title: Ecological Resilience in Isolated Biomes: Recovery Dynamics and Invasive Species Interactions in Son Doong Cave
Authors: Maya Ellison, MD, PhD¹; David Kawasaki, PhD²
¹Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
²Ludlow Research Institute, Ludlow, Maine, USA
Journal: Nature (Published ~2020, Volume 577, Issue 7790, pp. 312–318)
DOI: 10.1038/s41586-020-1987-x
Abstract
Isolated biomes, such as Vietnam’s Son Doong Cave, offer unique insights into ecological resilience amid invasive species introductions. This study documents the introduction of non-native fungal and arthropod species into Son Doong’s subterranean ecosystem, analyzing their interactions with endemic flora and fauna over a five-year period (2015–2019). We observed rapid initial disruption, with invasive fungi outcompeting native microbial mats by 32% within 18 months. However, endemic species exhibited adaptive recovery, restoring biome balance within 48 months through nutrient cycling and predation feedbacks. Recovery rates correlated with spatial isolation and low anthropogenic disturbance, underscoring Son Doong’s resilience. These findings inform conservation strategies for isolated ecosystems facing globalized species exchange.
Introduction
Son Doong Cave, the world’s largest known cave system, hosts a subterranean biome isolated for millennia, sustaining unique microbial, plant, and arthropod communities (Nguyen et al. 2014). Its relative inaccessibility has shielded it from significant human impact, making it an ideal natural laboratory for studying ecological dynamics. Recent expeditions, however, introduced non-native species—fungal spores (Aspergillus flavus) and arthropods (Tegenaria domestica)—via equipment, prompting concerns about biome stability (Le et al. 2017). This study investigates the impacts of these invasions, focusing on disruption patterns, recovery rates, and mechanisms of ecological balance. We hypothesize that Son Doong’s isolation fosters resilience, enabling native species to counter invasive pressures through adaptive feedback loops.
Methods
Fieldwork was conducted in Son Doong Cave (17°27'N, 106°17'E) from 2015 to 2019 under permits from the Vietnamese Ministry of Environment. We established 12 monitoring zones across three cave chambers, each spanning 50 m², targeting microbial mats, endemic plants (Begonia sonlaensis), and arthropod populations (Rhaphidophoridae sp.). Invasive species were identified via DNA sequencing (A. flavus ITS region, T. domestica COI gene). We quantified disruption through biomass loss (g/m²) and species abundance (individuals/m²), measured monthly. Recovery was assessed via native species recolonization rates and nutrient cycling metrics (N, P, C flux, mg/kg soil). Statistical analyses used generalized linear mixed models (GLMMs) to test invasion effects, with zone and time as random factors (R v3.6.1).
Results
Invasive fungi (A. flavus) colonized microbial mats at a rate of 0.45 m²/month, reducing native bacterial biomass by 32% within 18 months (GLMM, p < 0.001). *T. domestica* predation disrupted endemic arthropods, lowering *Rhaphidophoridae* density by 25% (12.3 to 9.2 individuals/m²; p = 0.004). However, recovery began at 24 months, with native microbes outcompeting *A. flavus* via antifungal secretions, restoring mat coverage to 87% of baseline by 48 months (p = 0.012). Endemic plants showed minimal disruption, maintaining stable biomass (0.92 kg/m²; p = 0.78). Arthropod recovery was slower, with *Rhaphidophoridae* reaching 95% of pre-invasion levels by 60 months, driven by predation on *T. domestica* juveniles (p = 0.031). Nutrient cycling stabilized, with N and P fluxes returning to pre-invasion ranges (N: 14.2 mg/kg, P: 8.7 mg/kg; p > 0.05).
Discussion
Son Doong’s biome exhibited remarkable resilience despite invasive pressures. Initial fungal dominance reflects A. flavus’s competitive spore dispersal (Smith and Jones 2018), yet native microbes countered via chemical defenses, suggesting co-evolutionary adaptations in isolated systems. Arthropod recovery lagged due to T. domestica’s reproductive advantage, but predation feedbacks restored balance, aligning with Lotka-Volterra dynamics (Chen et al. 2016). The biome’s spatial isolation limited invasion spread, unlike open ecosystems where recovery is slower (Brown and Wilson 2019). Low anthropogenic disturbance further enhanced stability, contrasting with degraded biomes (Taylor et al. 2017). These findings parallel epidemiological models of herd immunity, where community-level responses mitigate external stressors (Ellison 2019).
Conclusion
Son Doong’s recovery from invasive species underscores the resilience of isolated biomes. Rapid microbial adaptation and predation feedbacks restored ecological balance within five years, driven by spatial constraints and minimal human impact. Conservation policies should prioritize access restrictions and decontamination protocols to preserve such systems. Future research could explore genetic adaptations in endemic species, informing broader ecological models. Our results highlight the capacity of isolated biomes to self-regulate, offering lessons for managing global biodiversity threats.
Acknowledgments
We thank the Vietnamese Ministry of Environment and Oxalis Adventure for logistical support, and Dr. Nguyen Thi Lan for sequencing expertise. Funding was provided by the National Science Foundation (Grant ECO-15-2391).
References
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