The effects of phenological mismatches on demography

Abstract

Climate change is altering the phenology of species across the world, but what are the consequences of these phenological changes for the demography and population dynamics of species? Time-sensitive relationships, such as migration, breeding and predation, may be disrupted or altered, which may in turn alter the rates of reproduction and survival, leading some populations to decline and others to increase in abundance. However, finding evidence for disrupted relationships, or lack thereof, and their demographic effects, is difficult because the necessary detailed observational data are rare. Moreover, we do not know how sensitive species will generally be to phenological mismatches when they occur. Existing long-term studies provide preliminary data for analysing the phenology and demography of species in several locations. In many instances, though, observational protocols may need to be optimized to characterize timing-based multi-trophic interactions. As a basis for future research, we outline some of the key questions and approaches to improving our understanding of the relationships among phenology, demography and climate in a multi-trophic context. There are many challenges associated with this line of research, not the least of which is the need for detailed, long-term data on many organisms in a single system. However, we identify key questions that can be addressed with data that already exist and propose approaches that could guide future research.

Phenological asynchrony between herbivorous insects and their hosts: signal of climate change or pre-existing adaptive strategy?

“…In both the bay checkerspot and the winter moth, difficulty in documenting long-term changes in phenological synchrony stems partly from successive groups of researchers having recorded information on phenologies, fitnesses, and so on in different ways that are not strictly comparable. In order to properly record both phenological change and the population dynamic responses emerging from it, we will need better standardization of observations (Visser & Both 2005;Miller-Rushing et al 2010), as well as funding support for long-term monitoring of a suite of ecological measures on target species.…”

Toward a synthetic understanding of the role of phenology in ecology and evolution

“…It is possible that 'mismatched' species or individuals can often switch to other food sources or move elsewhere. As discussed by Miller-Rushing et al (2010), the population biology of phenology is an area where much work remains to be done.…”

“…In practice, however, there are still few examples of such shifts having detectable demographic consequences. Reasons for this persistent gap, and possible solutions, are discussed by Miller-Rushing et al (2010). A convincing demonstration requires showing that a change in interaction strength or frequency has occurred, that this change is the result of climate change and that the change has altered the vital rates of one or more of the species involved.…”

Long-term monitoring at multiple trophic levels suggests heterogeneity in responses to climate change in the Canadian Arctic tundra

“…plants, herbivores and predators). The last point is important because, for endotherms inhabiting the tundra, it has been suggested that the most severe impact of climate warming may be indirect, through alterations in trophic interactions such as change in food availability, predation pressure, apparition of new competitors or mismatch between trophic levels [25][26][27]. Therefore, a food web approach is essential in order to fully understand the impact of climate warming on individual species [28].…”