Occurrences and R code for: Dynamic distribution modeling of the Swamp Tigertail dragonfly Synthemis eustalacta (Odonata: Anisoptera: Synthemistidae) over a 20-year bushfire regime

Intensity and severity of bushfires in Australia have increased over the
past few decades due to climate change, threatening habitat loss for
numerous species. Although the impact of bushfires on vertebrates is
well-documented, the corresponding effects on insect taxa are rarely
examined, although they are responsible for key ecosystem functions and
services. Understanding the effects of bushfire seasons on insect
distributions could elucidate long-term impacts and patterns of ecosystem
recovery. Here, we investigated the effects of recent bushfires,
land-cover change, and climatic variables on the distribution of a common
and endemic dragonfly, the swamp tigertail (Synthemis eustalacta
(Burmeister, 1839)), which inhabits forests that have recently undergone
severe burning. We used a temporally dynamic species distribution modeling
approach that incorporated 20 years of community-science data on dragonfly
occurrence and predictors based on fire, land cover, and climate to make
yearly predictions of suitability. We also compared this to an approach
that combines multiple temporally static models that use annual data. We
found that for both approaches, fire-specific variables had negligible
importance for the models, while percent of tree and non-vegetative cover
were the most important. We also found that the dynamic model outperformed
the static ones when evaluated with cross-validation. Model predictions
indicated temporal variation in area and spatial arrangement of suitable
habitat but no patterns of habitat expansion, contraction, or shifting.
These results highlight not only the efficacy of dynamic modeling to
capture spatiotemporal variables, such as vegetation cover for an endemic
insect species, but also provide a novel approach to mapping species
distributions with sparse locality records.

近几十年来，受气候变化影响，澳大利亚丛林野火的强度与烈度持续攀升，对诸多物种的栖息地造成了严重威胁。尽管野火对脊椎动物的影响已有充分文献记载，但针对昆虫类群的相关研究却极为匮乏——尽管昆虫支撑着众多关键的生态系统功能与服务。明晰野火季对昆虫分布的影响，有助于阐释生态系统恢复的长期效应与格局。本研究针对栖息于近期经历严重焚毁森林的常见特有蜻蜓物种——沼泽虎尾蜻（Synthemis eustalacta (Burmeister, 1839)），探究了近期野火、土地覆被变化以及气候变量对其分布的影响。我们采用了时间动态物种分布建模（temporally dynamic species distribution modeling）方法，整合了20年的蜻蜓出现记录的公民科学数据，以及基于野火、土地覆被与气候构建的预测因子，以开展年度适宜性预测。同时，我们将该方法与基于年度数据的多个时间静态模型的集成方法进行了对比。研究结果显示，两种建模方法中，野火相关变量对模型的重要性均可忽略不计，而树木覆盖率与非植被覆盖占比则是最重要的预测因子。此外，经交叉验证评估，动态模型的表现优于静态模型。模型预测结果表明，适宜栖息地的面积与空间布局存在时间变异，但未呈现栖息地扩张、收缩或移位的明确模式。本研究不仅验证了动态建模在捕捉特有昆虫物种相关时空变量（如植被覆被）方面的效能，还为利用稀疏分布点位记录绘制物种分布图谱提供了全新的研究路径。