A bust but no boom: responses of floodplain bird assemblages during and after prolonged drought

Abstract

Climate change alters the frequency and severity of extreme events, such as drought. Such events will be increasingly important in shaping communities as climate change intensifies. The ability of species to withstand extreme events (resistance) and to recover once adverse conditions abate (resilience) will determine their persistence. We estimated the resistance and resilience of bird species during and after a 13-year drought (the 'Big Dry') in floodplain forests in south-eastern Australia. We conducted bird surveys at the beginning and end of the Big Dry, and after the abrupt end to the drought (the 'Big Wet'), to evaluate species-specific changes in reporting rates among the three periods. We assessed changes in bird-breeding activity before and after the Big Wet to estimate demographic resilience based on breeding. Between the start and the end of the Big Dry (1998 vs. 2009), 37 of 67 species declined substantially. Of those, only two had increased reporting rates after the Big Wet (2009 vs. 2013) that were equal to or larger than their declines, while three partially recovered. All other declining species showed low resilience: 25 showed no change in reporting rates and seven declined further. The number of breeding species and total breeding activity of all species declined after the Big Wet, and there was no change in the number of young produced. The Big Dry caused widespread declines in the floodplain avifauna. Despite the drought being broken by 2 years of well-above-average rainfall and subsequent near-average rainfall, most species showed low resilience and there was little indication that overall breeding had increased. The effects of drought appeared to be pervasive for much of the floodplain avifauna, regardless of species traits (species body mass, fecundity, mobility or diet). Ecosystems such as these are likely to require active management and restoration, including reinstatement of natural flooding regimes, to improve ecological condition, to enhance resistance and resilience to extreme climate events.

The power to detect regional declines in common bird populations using continental monitoring data

“…In addition, our simulation focused primarily on regions where species with “boom‐and‐bust” dynamics are not dominant (Selwood et al. ), with the exception of Alice Springs. Power estimates might vary where longer time series are considered necessary to identify a population trajectory (Gerrodette ).…”

Interactive effects of severe drought and grazing on the life history cycle of a bioindicator species

“…Using the lesser prairie‐chicken population on the Southern High Plains as a bioindicator of wildlife response to intense drought supports burgeoning evidence that wildlife is negatively affected by above average frequencies of drought and, over the long‐term, may not be adapted to the magnitude of drought expected with climate change. In fact, negative effects of increases in drought magnitude and frequency have been documented for all taxa, including amphibians (Mac Nally, Horrocks, & Lada, ), reptiles (Westphal, Stewart, Tennant, Butterfield, & Sinervo, ), fish (Jaeger, Olden, & Pelland, ), mammals (Ahlers et al., ), and birds (Selwood et al., ). Like other wildlife species in arid and semiarid grasslands, lesser prairie‐chickens on the Southern High Plains have adaptations that increase resilience to extreme environments and fluctuating weather patterns; however, environmental conditions expected from climate change may be outside of their adaptive potential, particularly in the time frame weather changes are expected to occur.…”

Extreme streams: species persistence and genomic change in montane insect populations across a flooding gradient

“…Prolonged extreme events may prevent near‐term species recovery, as shown for floodplain birds following years‐long drought (Selwood et al . ). Furthermore, the impact of an extreme event on species can vary according to landscape features that modulate the effective intensity of the event (Boucek et al .…”