Species Distribution Modeling Identifies Climatic Drivers of <i>Morchella diminutiva</i> Endemism

<jats:p>&lt;i&gt;Morchella diminutiva&lt;/i&gt; is a relatively small species of morel, commonly found in temperate hardwood forests in eastern North America. It is typically found in forests containing &lt;i&gt;Fraxinus americana&lt;/i&gt;, &lt;i&gt;Liriodendron tulipifera&lt;/i&gt;, and &lt;i&gt;Quercus spp.&lt;/i&gt; and is considered a soil saprotroph based on previous functional gene annotations. Using MaxEnt, we analyzed publicly available occurrence data of &lt;i&gt;M. diminutiva&lt;/i&gt; along with a variety of bioclimatic, land cover, and edaphic variables to predict the distribution of &lt;i&gt;M. diminutiva&lt;/i&gt; across the contiguous Unites States. Reported ascomata were identified between March and June, with most collections occurring in April. Precipitation seasonality, precipitation in the driest quarter, mean temperature in the coldest quarter, and forest type were found to be the most important factors driving&lt;i&gt; M. diminutiva&lt;/i&gt; distribution. Therefore, fruiting patterns of&lt;i&gt; M. diminutiva&lt;/i&gt; are strongly influenced by precipitation and temperature during winter months. &lt;i&gt;Morchella diminutiva&lt;/i&gt; displays strong regional endemism and habitat specificity in and around the Appalachian region, suggesting a preference for hardwood temperate forest habitats in eastern North America.</jats:p>