Data from: Balancing ecological costs and benefits of fire for population viability of disturbance-dependent butterflies

Disturbance is a fundamental ecological process and driver of population dynamics. Ecologists seek to understand the effects of disturbance on ecological systems and to use disturbance to modify habitats degraded by anthropogenic change. Demographic responses by plants to disturbance are often well described, but demographic responses by animals are less understood. This limits development of applied strategies that leverage disturbance to augment animal populations.
We estimated demographic and behavioural responses of an endangered butterfly, Fender's blue, Plebejus icarioides fenderi, to experimental burning in Oregon, USA. We monitored butterfly vital rates for four years post-fire.
Prescribed fire killed Fender's blue larvae. However, fecundity was higher relative to reference/unburned areas for two years after the burn and overwinter larval survivorship was higher for a year after the burn. Fire treatments did not influence adult movement behaviour.
We used matrix models to project butterfly population dynamics in fire-driven successional landscapes. We compared optimal burn strategies given targeted burns, such as prescribed fire, to undirected burns, such as wildfires. Disturbance enhances population growth rate under both strategies, and the optimal proportion of landscape burned is similar in both cases. However, targeted burning leads to substantially higher population growth rates.
Synthesis and applications. Demographic models allow planning of long-term and large-scale disturbance by balancing initial costs of disturbance with subsequent benefits. We use matrix models to project population growth in fire-driven successional landscapes and contrast prescribed burns with undirected burns (wildfires). We also use these models to evaluate the influence of local vs. non-local dispersal. Because random (non-local) dispersal allows individuals to disperse into areas that were just burned, non-local dispersal always increases population growth rates in this system. This contrasts with source-sink dynamics in stationary environments, in which local dispersal leads to higher population growth rates. Our matrix modelling approach has broad application to other disturbance-dependent taxa surviving in anthropogenically modified landscapes, and could be more widely applied to animal populations.

干扰（disturbance）是核心生态学过程之一，同时也是种群动态的关键驱动因子。生态学家旨在解析干扰对生态系统的作用机制，并借助干扰手段修复受人类活动影响而退化的生境。目前学界对植物响应干扰的种群动态特征已有较为充分的研究，但对动物的此类响应仍缺乏足够认知，这制约了借助干扰提升动物种群数量的应用策略开发。

本研究针对美国俄勒冈州的实验性火烧，评估了濒危蝴蝶芬德蓝蝶（Fender's blue，*Plebejus icarioides fenderi*）对火烧干扰的种群动态与行为响应，并在火烧后连续四年监测了该蝶类的生命率（vital rates）。

受控火烧（prescribed fire）会致死芬德蓝蝶的幼虫。不过在火烧后的两年内，该蝶的繁殖力相较于对照/未火烧区域显著提升，且火烧后一年内的越冬幼虫存活率也有所升高。此外，火烧处理对成虫的移动行为无显著影响。

我们借助矩阵模型（matrix models）预测了火烧驱动的演替景观中蝶类的种群动态。研究对比了以受控火烧为代表的针对性火烧策略，与以野火（wildfires）为代表的无定向火烧策略的最优实施方案。结果显示，两种策略下干扰均能提升种群增长率，且最优火烧覆盖的景观比例较为相近，但针对性火烧可使种群增长率获得更为显著的提升。

综合与应用。种群动态模型可通过权衡干扰的初始投入成本与后续收益，实现长期、大规模干扰的科学规划。本研究借助矩阵模型预测了火烧驱动演替景观中的种群增长情况，并对比了受控火烧与无定向火烧（野火）的差异。此外，研究还利用该模型评估了局域扩散（local dispersal）与非局域扩散（non-local dispersal）的影响：由于随机（非局域）扩散可使个体迁入刚被火烧过的区域，因此在本研究系统中，非局域扩散总能提升种群增长率。这与静态环境中的源汇动态（source-sink dynamics）形成鲜明对比——在静态环境中，局域扩散可带来更高的种群增长率。本研究的矩阵建模方法，对其他依赖干扰且存活于人为改造景观中的类群（taxa）具有广泛的应用潜力，且可进一步推广至更多动物种群的相关研究中。