A review of subtropical community resistance and resilience to extreme cold spells

Abstract

Abstract. Forecasted changes in global climate predict not only shifts in average conditions but also changes in the frequency and intensity of climate extremes. In the subtropics, the passage of extreme cold spells functions as a major structuring force for ecological communities, and can incur substantial losses to biodiversity, agriculture, and infrastructure. If these events persist in the future, it is likely that their effects on subtropical communities and ecosystems will become more pronounced, as tropical species migrate poleward. Recent extreme cold spells in subtropical China (2008) and United States (2010) occurred in ecosystems that are the subject of long-term ecological study, enabling key questions about cold spell affects to be addressed. In this study, we (1) discuss the meteorological drivers that resulted in these two extreme cold spells, and (2) use findings from case studies published in the Ecosphere Special Feature on effects of extreme cold spells on the dynamics of subtropical communities, and on poleward expansion of tropical species and other previously published works to identify consistencies of subtropical community resilience and resistance to extreme cold spells. In this review, we highlight three consistent findings related to this particularly type of extreme climate event: (1) cold spells drive predictable community change in the subtropics by altering ratios of coexisting tropical and temperate species; (2) certain landscape features consistently affect subtropical resistance and resilience to extreme cold spells; and (3) native tropical species are more resistant and resilient to extreme cold spells than tropical nonnative taxa. Our review should improve forecasts of the response of subtropical community dynamics in scenarios where extreme cold spells either increase or decrease in frequency and intensity.

Investigating Sub-tropical Community Resistance and Resilience to Climate Disturbance

“…In the sub-tropics and across a suite of ecosystem types, the degree of coldness experienced by habitat patches from extreme cold spells varies depending on landscape contexts (Reviewed in Boucek et al 2016a). For instance, in coastal aquatic systems of South Florida, coral community resistance was largely a function of their distance to warm water ocean currents.…”

“…Tropical species in Everglades National Park and in the sub-tropics, both are unable to physiologically tolerate extreme cold temperatures (thermal specialists Tweksbery 2010), and utilize behaviors that hinder their survival during extreme cold spells (Boucek et al 2016a). For instance, tropical American Crocodiles show maladaptive behaviors during extreme cold spells compared to more temperate American Alligators (Mazzotti et al 2016).…”

“…Animals should distribute themselves non-randomly in space and in time based of a suite of intrinsic and extrinsic drivers, thus creating dynamic spatiotemporal animal densities across habitats (Nathan et al 2008). In conjunction with animal spatial-temporally dynamic habitat use patterns, previous research of disturbance shows that the intensity of stressors, the buffering capacity of habitat patches (i.e., ability to modulate the intensity of stressors), and the magnitude of ecological effects varies across space (White & Jenstch 2001;Nimmo et al 2015;Boucek et al 2016a). Thus, by combining information on the spatial pattern of disturbance and on animal habitat use, we can potentially identify mechanisms responsible for faunal population change from ECEs.…”

“…multiple consecutive cold events) that result in isolated effects to natural systems occur once every 10 years. And, importantly, extreme cold spells that cause catastrophic losses to natural resources, and non-linear ecosystem change occur once every 20-30 years (Boucek et al 2016a). These extreme disturbances are abrupt, decreasing temperatures to lethal levels for vulnerable species within days, resulting in punctuated and mass mortality events that are highly visible to the public, and as a consequence, effects of these disturbances are well publicized.…”

“…Of particular importance, these extreme cold spells drive population crashes of many of Florida's economically important tropical sportfishes, including bonefish, juvenile goliath groupers, and common snook (Santos et al 2016). The effects of these disturbances on sportfishes result in substantial economic losses for those who rely on those resources (Boucek et al 2016a;Stevens et al 2016).…”