Phenological Changes in the Southern Hemisphere

Abstract

Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported.

Fitness implications of seasonal climate variation in Columbian ground squirrels

“…2013; Chambers et al. 2013; Møller 2013). Spring snowfall in the year that followed reproduction was also associated with lowered fitness, resulting in this case primarily from significantly lower survival of breeding females.…”

“…2010; Chambers et al. 2013). Our use of annual fitness included influences on reproduction, both the timing of reproduction in a temperate environment (Lane et al.…”

“…This is particularly true in the northern temperate zone, where climate change is expected to be most dramatic (Chambers et al. 2013). Collectively, these studies demonstrate a general pattern of earlier timing of reproduction in response to climate warming that advances the onset of spring (Parmesan 2006; Thackeray et al.…”

“…2010; Chambers et al. 2013). However, delays in phenology may also produce detrimental fitness consequences (Lane et al.…”

“…2012; Chambers et al. 2013). While intuitive, there is surprisingly little evidence that specifically links climate change to variation in population dynamics and, by extension, viability.…”