Phenology of hatching and food in low Arctic passerines and shorebirds: is there a mismatch?

Maria C.-Y Leung,Alice J Kenney,Donald G Reid,B Scott Gilbert,Elise Bolduc,Joël Bêty,Charles J Krebs,Frank I Doyle

doi:10.1139/as-2017-0054

Abstract

The warming climate is driving earlier spring snow melt and longer growing seasons in tundra regions of northwestern North America, thereby changing the timing of ecological processes. On Herschel Island, Yukon, Canada, we investigated changes in the migratory bird community, and the potential for phenological mismatch of egg hatching with the pulses in abundance of arthropod prey on which young birds depend for growth. We found an apparent reduction in abundance or loss of some species dependent on freshwater ponds or sparsely vegetated upland tundra. Tracking hatch dates of passerines and shorebirds along with the changes in biomass of mobile life history stages of arthropods (principally Araneae, Tipulidae, Carabidae, Muscidae, Chironomidae, Mycetophilidae, and Ichneumonidae), we found no evidence for phenological mismatch in the 2007–2009 time period. Most nests hatched, and the period of most rapid chick growth occurred, in advance of the highest availability of arthropod biomass. Shorebirds hatched significantly later than passerines, less in advance of the peak abundances of arthropods. They are most at risk of future mismatch, given likely trend to earlier onset of arthropod availability and longer migration routes. Herschel Island is a well-studied site warranting further monitoring to assess changes in the Arctic tundra ecosystem.

Highlights

Arctic regions, especially in northwestern North America, have experienced and are expected to experience among the fastest rates of climate change, with dramatic impacts on the cryosphere (IPCC 2013)
In the 2000s, we found nests of four species for which nests were not found in the 1980s: sandhill crane (Antigone canadensis); buff-breasted sandpiper (BBSA) (Calidris subruficollis); least sandpiper; and white-crowned sparrow (Zonotrichia leucophrys)
Since the 1980s there have been a few changes in the composition of the nesting bird community on the east end of Herschel Island, characterised by a loss of two species currently facing population declines (Zöckler et al 2013) and associated with brackish and freshwater ponds (RNPH and RUTU), and a gain of some species more typically associated, at least west of the Mackenzie River, with boreal and subarctic habitats [sandhill crane (SACR), Least sandpiper (LESA), and white-crowned sparrow (WCSP)] (Chilton et al 1995; Nebel and Cooper 2008; Eckert 2012; Gerber et al 2014)

Summary

Introduction

Especially in northwestern North America, have experienced and are expected to experience among the fastest rates of climate change, with dramatic impacts on the cryosphere (IPCC 2013). Change is evident on tundra of northwestern North America, with increasing mean annual temperature, increasing spring temperature associated with earlier snow melt, increasing duration of snow-free period, and increasing precipitation (Stone et al 2002; Brown and Robinson 2011; Burn 2012a; Candlish et al 2015). Such changes are having pervasive influences on Arctic biodiversity (Meltofte et al 2013). Among the ecosystem processes potentially affected by temperature are the timing of arrival and egg-laying in migratory birds which nest on snow-free ground (Ganter et al 2013), and the emergence and hatch of diverse arthropod taxa which are crucial prey for many nesting birds (Meltofte et al 2007a, 2007b)

Methods

Results

Conclusion