Erica Nol Profile picture
7 Oct, 23 tweets, 18 min read
1/23 Thanks first to organizers of this new age conference, for inviting me to join in. I am very excited to be here with shorebird researchers from around the Twitter and real worlds #ISTC20 #SESH3 #ornithology #Waders
2/25 My tweets will explore the effects of extreme weather events on the demography of a small sub-arctic breeding shorebird: Semipalmated Plover (Charadrius semipalmatus) #ISTC20 #SESH3
3/23 Much attention of climate research and birds has been on warming: mismatching phenology in particular. But we know extreme weather can have a major impact on pop’n. Deaths of these songbirds probably due to recent fires and drought in western USA #ISTC20 #SESH3
4/23 Life histories of arctic-breeding birds have been moulded by extreme weather so why are we concerned? Big eggs, income breeders, body fat for cold spells #ISTC20 #SESH3
5/23 Meteorologists document consistent directional changes in frequency of unusual climatic events. Here are places in orange @CanadaNorthern that show more frequent freezing precipitation over last 50 y #ISTC20 #SESH3
6/23 My students and I have studied shorebirds nesting in habitats around Churchill, Manitoba, Canada for nearly 30 yrs. The longest running of these studies is on the Semipalmated Plover. #ISTC20 #SESH3
7/23 Fieldwork has been conducted regularly at 10 sites in region, based out of very comfortable @ChurchillNSC #ISTC20 #Sesh3
8/23 Habitats range from the edge of the boreal forest to pebble/sand beaches and mudflats to gravel exposed by removing tundra topsoil for several failed development projects. #ISTC20 #SESH3
9/23 Plover population has remained stable for nearly 20 y with some exceptions #ISTC20 #SESH3
10/23 First notable exception was result of 1992 Pinatubo volcanic eruption that cast a layer of dust across the globe that cooled the planet. Population declined to less than 20 pairs #ISTC20 #SESH3 Impacts felt on many bird species.
11/23 Second exception was in 2000. Very cold spring with ice and snow present well into usual breeding season #ISTC20 #SESH3
12/23 #ISTC20 #SESH3
13/23 Two key mechanisms link climate with bird demography: the impact on a bird’s physiology and the impact on their food. Slide shows typical Scholander curve for endotherms and for plovers, plotting ambient temp and bmr. @CondorJournal #ISTC20 #SESH3 Temp below 23o = elevated
14/23 Invertebrate prey are only active when threshold temp is reached. In this case 6o @kellielibera #ISTC20 #SESH3 Adults find food because they are more mobile. Chicks have harder time so effects can depend on life stage.
15/23 We have observed steady and significant decline of plovers since 2010 #ISTC20 #SESH3
16/23 Complete loss of plovers from three of most dependable and important sites #ISTC20 #SESH3 Note that many other researchers are noticing losses from study areas. #shorebirds
17/23 What has changed? Some supratidal nesting habitats degraded by staging geese and reduced to muddy soup. Ravens also seem more abundant.
18/23 Because we know temp has impact we want to see role in decline of persistent low temperatures caused by static polar vortices in spring. #ISTC20 #SESH3 Last five yrs have experienced low temps.
19/23 I used path analysis to look at independent effects of various potential causes of decline. Do combined effects of weather and steady decline in habitat quality explain local declines? #ISTC20 #SESH3 I used year as a proxy for a steady decline in habitat quality
20/23 Or perhaps a steady increase in predators, something that would impact only hatching or fledging success? #ISTC20 #SESH3
21/23 Analysis suggested weather and consistently cold springs impact future N through effects on timing of laying, which then affected fledging success. FS has little effect on future N. If late spring, birds give up on laying. Pop’n maintained by immigration #ISTC20 #SESH3
22/23 Impact of persistent polar vortex in other small Hudson Bay lowland breeding shorebirds very likely because their laying dates, hatching success and pop’n sizes correlated to those of Semipalmated Plovers #ISTC #SESH3
23/23 Thanks to all former Semipalmated Plover students and the funders and @IBIS_journal @WaderStudy #ISTC20 #SESH3

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