{ "152565-21913921": { "datetime_modified":"20260921T131719", "datetime_start":"20261009T153000", "datetime_end":"20261009T163000", "has_end_time":1, "date_start":"2026-10-09", "date_end":"2026-10-09", "time_start":"15:30:00", "time_end":"16:30:00", "time_zone":"America\/Detroit", "event_title":"Smith Lecture: Maya Samuels-Fair", "occurrence_title":"", "combined_title":"Smith Lecture: Maya Samuels-Fair: When is ecological change evidence of selective extinction? Simulating the effect of random extinction on functional diversity in ecosystems with variable rank-abundance distributions", "event_subtitle":"When is ecological change evidence of selective extinction? Simulating the effect of random extinction on functional diversity in ecosystems with variable rank-abundance distributions", "event_type":"Lecture \/ Discussion", "event_type_id":"13", "description":"Selective extinction by definition causes some groups to become extinct at higher rates than others and is often assumed to be the cause of functional diversity changes following mass extinctions. However, significant changes in functional diversity can occur even when extinction is nonselective (random). Counterintuitively, lack of functional diversity change can also be evidence of selective extinction. This can occur because (1) the number of taxa in each functional group varies and (2) the abundance of each functional group varies. Consequently, random removal of taxa or individuals disproportionately affects rare functional groups. We simulate random extinction with a range of initial rank abundance distributions, varying the number of taxa in each functional group and the evenness of abundances across taxa. We then measure change in functional diversity before and after random extinction using PERMANOVA. This generates a null distribution of how functional diversity would be expected to change under random extinction for each initial rank abundance distribution. Change in functional diversity outside the null distribution is then positive evidence of nonrandom extinction, nonrandom origination, or nonrandom changes in abundance. \n \nWe apply this approach to examine changes in the bryozoan fauna of Stevns Klint, Denmark following the Cretaceous-Paleogene mass extinction, using a dataset of 4,453 specimens from 13 pre-extinction and 7 post-extinction samples. We find that functional diversity changes significantly across the K\/Pg boundary, but functional change is largely consistent with random extinction, followed by an increase in the abundances of the functional groups with the fewest taxa. Our approach thus allows us to differentiate between selection extinction and other mechanisms of functional diversity change, which can be applied to other extinction events.", "occurrence_notes":null, "guid":"152565-21913921@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/152565", "building_id":"1000188", "building_name":"1100 North University Building", "campus_maps_id":"628", "room":"1528", "location_name":"1100 North University Building", "has_livestream":0, "cost":"", "tags":["Earth And Environmental Sciences"], "website":"", "sponsors":[ { "group_name":"Earth and Environmental Sciences", "group_id":"3170", "website":"http:\/\/www.lsa.umich.edu\/earth" } ], "image_url":"https:\/\/events.umich.edu\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "styled_images":{ "event_thumb":"https:\/\/events.umich.edu\/media\/cache\/event_thumb\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_large":"https:\/\/events.umich.edu\/media\/cache\/event_large\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_large_2x":"https:\/\/events.umich.edu\/media\/cache\/event_large_2x\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/event_large_lightbox\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "group_thumb":"https:\/\/events.umich.edu\/media\/cache\/group_thumb\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "group_thumb_square":"https:\/\/events.umich.edu\/media\/cache\/group_thumb_square\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "group_large":"https:\/\/events.umich.edu\/media\/cache\/group_large\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "group_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/group_large_lightbox\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_large_crop":"https:\/\/events.umich.edu\/media\/cache\/event_large_crop\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_list":"https:\/\/events.umich.edu\/media\/cache\/event_list\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_list_2x":"https:\/\/events.umich.edu\/media\/cache\/event_list_2x\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_grid":"https:\/\/events.umich.edu\/media\/cache\/event_grid\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_grid_2x":"https:\/\/events.umich.edu\/media\/cache\/event_grid_2x\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_feature_large":"https:\/\/events.umich.edu\/media\/cache\/event_feature_large\/media\/attachments\/2026\/09\/event_152565_original-1.jpg", "event_feature_thumb":"https:\/\/events.umich.edu\/media\/cache\/event_feature_thumb\/media\/attachments\/2026\/09\/event_152565_original-1.jpg" }, "occurrence_count":1, "first_occurrence":21913921 } , "152566-21913922": { "datetime_modified":"20260921T132149", "datetime_start":"20261023T153000", "datetime_end":"20261023T163000", "has_end_time":1, "date_start":"2026-10-23", "date_end":"2026-10-23", "time_start":"15:30:00", "time_end":"16:30:00", "time_zone":"America\/Detroit", "event_title":"Smith Lecture: Qinya Liu", "occurrence_title":"", "combined_title":"Smith Lecture: Qinya Liu: High-resolution full-waveform seismic imaging beneath seismic arrays based on ambient-noise and teleseismic body waves", "event_subtitle":"High-resolution full-waveform seismic imaging beneath seismic arrays based on ambient-noise and teleseismic body waves", "event_type":"Lecture \/ Discussion", "event_type_id":"13", "description":"The field of seismic imaging has witnessed significant advances in the past two decades resulting from the combined improvement in observational and computational seismology, including 1) increased deployment of broadband regional seismic arrays, including dense linear arrays, 2) the use of innovative dataset such as ambient-noise cross-correlation functions and teleseismic scattered and converted waves. 3) full numerical simulations of seismic wave propagations at local, regional and global scales, and their applications to full-waveform inversions resulting in unprecedented high-resolution images of tectonic regions around the globe. To take full advantage of the dense seismic arrays, particularly for regions lacking seismicity, both ambient-noise data and teleseismic body waves can be inverted in the framework of full-waveform inversion (FWI). In this talk, I review the basic theory of utilizing these two dataset jointly in FWI, as well as in combination with local earthquake data, and show our recent lithospheric imaging applications beneath Alaska, and central Cascadia. The use of these innovative datasets in FWI provides complementary sensitivities, generates high-resolution images of the lithosphere, and hence contributes to improving their tectonic interpretations.", "occurrence_notes":null, "guid":"152566-21913922@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/152566", "building_id":"1000188", "building_name":"1100 North University Building", "campus_maps_id":"628", "room":"1528", "location_name":"1100 North University Building", "has_livestream":0, "cost":"", "tags":["Earth And Environmental Sciences"], "website":"", "sponsors":[ { "group_name":"Earth and Environmental Sciences", "group_id":"3170", "website":"http:\/\/www.lsa.umich.edu\/earth" } ], "image_url":"https:\/\/events.umich.edu\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "styled_images":{ "event_thumb":"https:\/\/events.umich.edu\/media\/cache\/event_thumb\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_large":"https:\/\/events.umich.edu\/media\/cache\/event_large\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_large_2x":"https:\/\/events.umich.edu\/media\/cache\/event_large_2x\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/event_large_lightbox\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "group_thumb":"https:\/\/events.umich.edu\/media\/cache\/group_thumb\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "group_thumb_square":"https:\/\/events.umich.edu\/media\/cache\/group_thumb_square\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "group_large":"https:\/\/events.umich.edu\/media\/cache\/group_large\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "group_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/group_large_lightbox\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_large_crop":"https:\/\/events.umich.edu\/media\/cache\/event_large_crop\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_list":"https:\/\/events.umich.edu\/media\/cache\/event_list\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_list_2x":"https:\/\/events.umich.edu\/media\/cache\/event_list_2x\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_grid":"https:\/\/events.umich.edu\/media\/cache\/event_grid\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_grid_2x":"https:\/\/events.umich.edu\/media\/cache\/event_grid_2x\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_feature_large":"https:\/\/events.umich.edu\/media\/cache\/event_feature_large\/media\/attachments\/2026\/09\/event_152566_original-1.jpg", "event_feature_thumb":"https:\/\/events.umich.edu\/media\/cache\/event_feature_thumb\/media\/attachments\/2026\/09\/event_152566_original-1.jpg" }, "occurrence_count":1, "first_occurrence":21913922 } }