Twenty-first-century globalization has led to an extraordinary rise in international trade and transit. Consequentially, invertebrates, plants, and mammals are displaced more frequently, which has catalyzed a historic rise in biological invasions. The Joro Spider (Araneae: Trichonephila clavata) recently established from Asia in a landlocked region of southern Appalachia. Its range continues to expand; its cold tolerance is expected to favor northward invasion. As a large-bodied orbweaver that forms extensive webs and aggregations, the Joro spider is likely capable of inducing fundamental change to community structure via spatial competition. A valuable first step in estimating any invader’s economic or biological impact is to hypothesize regions susceptible to invasion using species distribution models. Recent work also shows that comparing global and regional distribution models yields insight into different stages of invasion. To examine potential spread and niche utilization differences in the Joro spider, one global and two regional models were developed. Maximum Entropy models were trained using open-source citizen science occurrence data and six bioclimatic variables at 2.5-arcminute resolution. An AUC-weighted ensemble model was used to produce each of the 3 global suitability projections. To compare invasive stage differences, projections were then translated to presence-absence maps using a 50% suitability threshold. The Asia-regional model predicts widespread suitability in eastern North America. However, the US-regional model reflects local adaptation to a climate niche that does not occur in the spider’s historic Asian range. Permutation feature importance shows the US-regional model was driven mainly by precipitation seasonality (64%) and annual oscillations in daily temperature range (29.1%). The Asia-regional model was instead driven by mean temperature of the driest quarter (34.9%), maximum temperature of the warmest month (23.6%), and precipitation of the warmest quarter (20.1%). The introduced Joro spider has invaded a North American niche that it is naïve to, but which co-occurs spatially with a niche akin to its historic Asian niche. If the Asia-regional climatic niche is indeed exploitable in North America, then conservative estimates show the bounds of range suitability should approach the 95th meridian and the 28th and 50th parallels. A total of 1,231,711 km2 within North America was predicted above 50% suitability. Altogether, these findings suggest niche versatility and plentiful suitable habitat favors successful North American invasion by the Joro spider.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:asrf-2197 |
| Date | 25 April 2023 |
| Creators | Giulian, Joseph |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | Appalachian Student Research Forum |
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