{"id":853,"date":"2025-06-12T17:34:46","date_gmt":"2025-06-12T17:34:46","guid":{"rendered":"https:\/\/sites.tntech.edu\/skrosnick\/?page_id=853"},"modified":"2025-06-12T18:10:21","modified_gmt":"2025-06-12T18:10:21","slug":"reproductive-biology-in-physaria-globosa","status":"publish","type":"page","link":"https:\/\/sites.tntech.edu\/skrosnick\/reproductive-biology-in-physaria-globosa\/","title":{"rendered":"Reproductive Biology in Physaria globosa"},"content":{"rendered":"\n<h4 class=\"wp-block-heading\">Reproductive Biology in <em>Physaria globosa<\/em><\/h4>\n\n\n\n<p><em>Physaria globosa<\/em> (Short\u2019s Bladderpod) is a federally endangered species in the mustard family (Brassicaceae), occurring only in Tennessee, Kentucky, and Indiana. Unlike most <em>Physaria<\/em> species, which are concentrated in the arid western U.S., <em>P. globosa<\/em> represents one of the few eastern members of the genus and occupies specialized limestone habitats along major river systems including the Cumberland and Kentucky Rivers.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-scaled.jpeg\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"1024\" data-id=\"857\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-768x1024.jpeg\" alt=\"\" class=\"wp-image-857\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-768x1024.jpeg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-225x300.jpeg 225w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-1152x1536.jpeg 1152w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-1536x2048.jpeg 1536w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/File_001-scaled.jpeg 1920w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/a><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full is-style-default\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"2560\" height=\"1707\" data-id=\"859\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-scaled.jpg\" alt=\"\" class=\"wp-image-859\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-scaled.jpg 2560w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-300x200.jpg 300w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-1024x683.jpg 1024w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-768x512.jpg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-1536x1024.jpg 1536w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/DSC_0151-edited-2048x1366.jpg 2048w\" sizes=\"auto, (max-width: 2560px) 100vw, 2560px\" \/><\/a><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"1024\" data-id=\"860\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-768x1024.jpg\" alt=\"\" class=\"wp-image-860\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-768x1024.jpg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-225x300.jpg 225w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-1152x1536.jpg 1152w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-1536x2048.jpg 1536w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/2025-04-09_10-38-49_622-scaled.jpg 1920w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/a><\/figure>\n<\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p>The species was listed as Federally Endangered in 2014 due to threats from habitat destruction, overstory shading, competition with invasive species, soil erosion, small population sizes, and altered hydrology. Currently, approximately 30\u201333 populations are known, most of which are small, isolated, and vulnerable to stochastic environmental changes.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Research Questions<\/h4>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"alignright size-large is-resized\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"1024\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-768x1024.jpg\" alt=\"\" class=\"wp-image-855\" style=\"width:153px;height:auto\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-768x1024.jpg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-225x300.jpg 225w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-1152x1536.jpg 1152w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-1536x2048.jpg 1536w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_8810-scaled.jpg 1920w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/a><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-left\">Our lab is actively working to advance the understanding of <em>Physaria globosa<\/em> reproductive biology, habitat ecology, and conservation needs. Major research questions include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>What insect species serve as effective pollinators for <em>P. globosa<\/em>?<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>How does reproductive output vary across environmental gradients and populations?<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>What abiotic factors influence growth, fecundity, and population stability?<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>What is the life history of this species, and what indicators can be identified that help predict    population size from year to year? <\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Is reproduction limited by self-incompatibility, pollen limitation, or low pollinator visitation?<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>How can emerging methods (e.g., eDNA metabarcoding) help inform conservation management?<br><\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Field Studies and Key Findings<\/strong><\/h4>\n\n\n\n<h4 class=\"wp-block-heading\">Pollination Ecology<\/h4>\n\n\n\n<p>Initial field studies conducted at one of the largest Tennessee populations (Hartsville, Trousdale County) identified a diverse assemblage of floral visitors. Effective pollinators included two syrphid flies (<em>Nemotelus bruesii<\/em>, <em>Toxomerus geminatus<\/em>) and four halictid bees (<em>Lasioglossum illinoense<\/em>, <em>L. versatus<\/em>, <em>Halictus ligatus<\/em>, <em>Augochlorella striata<\/em>) (Thacker et al. 2019). This diversity contrasts with western <em>Physaria<\/em> species, where ground-nesting bees are often the dominant pollinators.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Reproductive Dynamics and Fecundity<\/h4>\n\n\n\n<p>Subsequent work at the same Tennessee site examined patterns of fruit production, flowering stem number, seed set, and resource allocation (Krosnick et al. 2022). Reproductive output was strongly correlated with basal stem diameter and flowering stem number, while environmental factors like light levels and soil depth had weaker effects. Many individuals flower over multiple years, and robust plants are typically found in open-canopy limestone outcrops with shallow soils.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Pollen Limitation Across the Range<\/h4>\n\n\n\n<p>Expanded studies across Tennessee, Kentucky, and Indiana documented varying levels of pollen limitation among populations (Powell &amp; Krosnick, 2022). Populations in Kentucky and Indiana showed evidence of pollen limitation, while Tennessee populations did not. These findings emphasize the importance of pollinator availability for some populations.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Range-Wide Pollinator Communities<\/h4>\n\n\n\n<p>Waters et al. (2025) documented floral visitors across multiple populations to better characterize pollinator communities range-wide. Early results suggest that while flies were prominent in earlier studies, polylectic bees (e.g., <em>Lasioglossum<\/em>, <em>Andrena<\/em>, <em>Ceratina<\/em>) dominate in many populations. These findings help clarify both local and regional variation in pollination biology for <em>P. globosa<\/em>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Emerging Methods &amp; Metabarcoding Insights<\/h4>\n\n\n\n<p>In addition to field-based pollination studies, our lab is developing new molecular tools to better monitor plant\u2013pollinator interactions over time. This study utilized environmental DNA (eDNA) extracted from herbarium floral material collected across the range of <em>P. globosa<\/em>. By targeting COI and 16S markers, researchers recovered over 1.5 million reads spanning 29 distinct taxonomic lineages, including Hymenoptera, Lepidoptera, Coleoptera, birds, and mammals. Remarkably, viable eDNA was detectable even from specimens over 60 years old, demonstrating that herbarium specimens can serve as long-term archives of pollinator interactions for rare plants like <em>P. globosa<\/em>.<\/p>\n\n\n\n<p>This novel approach opens new avenues for monitoring pollinator communities over historical time periods, which may be particularly valuable for species at risk due to pollinator declines.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"1566\" height=\"1619\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24.jpg\" alt=\"\" class=\"wp-image-869\" style=\"width:410px;height:auto\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24.jpg 1566w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24-290x300.jpg 290w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24-990x1024.jpg 990w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24-768x794.jpg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/Figure_1_10-15-24-1486x1536.jpg 1486w\" sizes=\"auto, (max-width: 1566px) 100vw, 1566px\" \/><\/a><\/figure>\n\n\n\n<p>Figure 1 from Waters et al. 2005, available <a href=\"https:\/\/bsapubs.onlinelibrary.wiley.com\/doi\/full\/10.1002\/aps3.11633?af=R\" data-type=\"link\" data-id=\"https:\/\/bsapubs.onlinelibrary.wiley.com\/doi\/full\/10.1002\/aps3.11633?af=R\">here<\/a>. <\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Conservation Implications<\/h4>\n\n\n\n<p>Collectively, our work provides essential data for federal and state conservation agencies working to manage and recover <em>Physaria globosa<\/em> populations. These studies:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Identify effective pollinators necessary for reproduction<\/li>\n\n\n\n<li>Clarify how habitat characteristics influence plant fecundity<\/li>\n\n\n\n<li>Document variation in pollen limitation across the species&#8217; range<\/li>\n\n\n\n<li>Introduce novel eDNA methods for long-term monitoring<\/li>\n\n\n\n<li>Inform habitat restoration and management strategies for recovery planning<\/li>\n<\/ul>\n\n\n\n<p>Our research supports the ongoing implementation of the U.S. Fish &amp; Wildlife Service Species Status Assessment and recovery efforts in Tennessee, Kentucky, and Indiana.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Sample Publications<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Thacker, J.H., Krosnick, S.E., Maynord, S.C., Call, G.P., &amp; Perkin, J.S. (2019). Pollination biology and reproductive phenology of the federally endangered endemic <em>Physaria globosa<\/em> (Brassicaceae) in Tennessee. <em>Journal of the Torrey Botanical Society<\/em>. <a href=\"https:\/\/doi.org\/10.3159\/torrey-d-17-00039.1\" target=\"_blank\" rel=\"noreferrer noopener\">10.3159\/TORREY-D-17-00039.1<\/a><\/li>\n\n\n\n<li>Krosnick, S.E., Thacker, J.H., Mattingly, H.T., Call, G.P., Maynord, S.C., Adams, D.S., &amp; Wheeler, K. (2022). Ecological correlates of reproductive output in a Tennessee population of Short\u2019s Bladderpod, <em>Physaria globosa<\/em> (Brassicaceae). <em>Castanea<\/em>, 87(1): 20\u201338. <a href=\"https:\/\/doi.org\/10.2179\/0008-7475.87.1.20\" target=\"_blank\" rel=\"noreferrer noopener\">10.2179\/0008-7475.87.1.20<\/a> <\/li>\n\n\n\n<li>Waters, C. G., Hurt, C. R., and S. E. Krosnick (2025). Looking to the past to inform the future: what eDNA from herbarium specimens can tell us about plant-animal interactions. <em>Applications in Plant Sciences<\/em>. 13:e11633. <a href=\"https:\/\/doi.org\/10.1002\/aps3.11633\">https:\/\/doi.org\/10.1002\/aps3.11633<\/a><br><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><a href=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-scaled.jpeg\"><img loading=\"lazy\" decoding=\"async\" width=\"1920\" height=\"2560\" src=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-scaled.jpeg\" alt=\"\" class=\"wp-image-868\" style=\"width:460px;height:auto\" srcset=\"https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-scaled.jpeg 1920w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-225x300.jpeg 225w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-768x1024.jpeg 768w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-1152x1536.jpeg 1152w, https:\/\/sites.tntech.edu\/skrosnick\/wp-content\/uploads\/sites\/44\/2025\/06\/IMG_2839-edited-1536x2048.jpeg 1536w\" sizes=\"auto, (max-width: 1920px) 100vw, 1920px\" \/><\/a><\/figure>\n\n\n","protected":false},"excerpt":{"rendered":"<p>Reproductive Biology in Physaria globosa Physaria globosa (Short\u2019s Bladderpod) is a federally endangered species in the mustard family (Brassicaceae), occurring only in Tennessee, Kentucky, and Indiana. Unlike most Physaria species, &#8230;<\/p>\n","protected":false},"author":47,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":"[]"},"class_list":["post-853","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/pages\/853","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/users\/47"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/comments?post=853"}],"version-history":[{"count":16,"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/pages\/853\/revisions"}],"predecessor-version":[{"id":888,"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/pages\/853\/revisions\/888"}],"wp:attachment":[{"href":"https:\/\/sites.tntech.edu\/skrosnick\/wp-json\/wp\/v2\/media?parent=853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}