Climate change and natural systems

Presentation abstracts:

Alex Pace, Jeannine-Marie St.-Jacques, & Duane Noel: Reproducing the conditions of past climate with tree rings in the mountains of the Gaspésie

A long record of a region’s climate is an important resource to understand an environment. It allows us to give context to climate change, distinguishing human-induced climate change from natural variability and is an important resource for the conservation of vulnerable plant and animal species. The Chic-Choc and McGerrigle Mountains that form the interior of the Gaspésie peninsula are among the highest peaks in the province of Québec and such mountainous regions are known to be sensitive early responders to climate change. The region has a unique ecosystem home to vulnerable wildlife: the river valleys are important Atlantic salmon spawning grounds and the summits are refuge for rare plant species and the last population of caribou remaining south of the Saint-Lawrence river. The mountains of the Gaspésie have relatively short weather records, beginning only after 1950, a timespan too brief to provide a robust understanding of climate in this region.

Short climate records can be supplemented at an annual resolution by studying the width and composition of tree rings. In seasonal climates, trees grow a distinct ring of wood every year that can hold valuable information about the surrounding environmental conditions. In this region, many areas with old trees have been protected as part of the Parc national de la Gaspésie, conserving several hundred years of natural climate records. In collaboration with the park, we have sampled hundreds of conifers, including eastern white cedars (Thuja occidentalis), black spruce (Picea mariana), white spruce (Picea glauca) and balsam firs (Abbies balsamea) in variety of locations from riverside cliffs to harsh mountaintops. The ancient trees of the region have allowed us to make a chronology of tree rings dating back to 1561 AD and we have mapped many of the oldest trees in the park. Collectively, these trees show a common pattern that has allowed us to develop a reconstruction of regional water availability that extends over 200 years into the past. Some sites also have potential for us to understand other aspects of climate like the past temperature and snowpack.

Jeannine-Marie St-Jacques, Claire O’Neill Sanger, Matthew Peros, & Kayden Schwartz: What can pollen tell us about the past? Reconstructing environmental variability over the last 2000 years using high-resolution pollen records from a small lake in Mont-Orford National Park

Long-term climate records are necessary for establishing reference conditions for ecosystem-based management and climate monitoring. In Canada, human recorded instrumental records of climate only span at most 100 years. Hence, to detect local environmental change due to global warming, we need longer-term environmental records in order to properly understand if recent changes are outside of the normal range of variability, or rather within the natural low-frequency variability of a region. Here in Quebec, numerous studies have used the paleoclimate-proxy of pollen extracted from lake mud to reconstruct forest dynamics and infer climate variability throughout the Holocene. However, in southeastern Quebec, high-resolution pollen records are lacking to more precisely assess centennial-scale climate variability over the past two millennia. In order to fill this paleo-environmental record gap and investigate forest-climate interactions at the centennial-scale over the past 2000 years, our research analyzes pollen from a sediment core taken from Étang Fer-de-Lance in Mont-Orford National Park. Sampled a resolution of approximately 10 years, the pollen record permits the reconstruction of domain boundary changes within the sugar-maple-hardwood forest subzone, as well as, land use changes due to possible Indigenous agriculture and European colonization of the Eastern Townships region. This study contributes to our understanding of the natural low-frequency forest dynamics of southeastern Québec.

Duane D. Noel, Jeannine-Marie St-Jacques, & Sunil Gurrapu: The effects of the Pacific Decadal Oscillation on flood maxima and frequency on the North American West Coast

The frequency of natural hazards occurring in North America present a major challenge for governments due to the damages they cause to residential and commercial infrastructure. Floods, a major weather-related event caused by spring snowmelt and intense precipitation occur yearly and jeopardize the safety of many Canadians. In hydrology, flood events are assumed to occur independently of each other. In this study, we tested the independent flood event assumption by analyzing the influence of the Pacific Decadal Oscillation (PDO) (an atmosphere-ocean climate oscillation of multi-decadal variability of North Pacific sea surface temperatures) on annual flood maxima series from 250 naturally flowing streamflow gauges across the western North American margin. We found that floods are higher in one phase of the PDO than in the other phase using Spearman’s rank correlation ρ and permutation tests on quantile-quantile (Q-Q) plots. The permutation tests showed that 40% of the stations had significantly different flood regimes depending on the PDO phase. We observed a distinct geographic pattern in which higher peak floods occurred in the negative PDO phase in central Alaska-Yukon and northern California-British Columbia, whereas higher peak floods occurred in the positive PDO phase in coastal southern Alaska-Yukon and southern California. We found similar results using Spearman’s rank correlation ρ. We also found similar results with two-sided permutation t-tests in which annual floods associated strongly with extreme PDO events. Furthermore, flood ratios from flood quantiles provide further evidence that the PDO impacts flood frequencies and magnitudes. Therefore, further research on climate oscillations such as the PDO should be conducted before designing new infrastructure near rivers due to the impact these oscillations have on floods. Our result illustrates the importance of re-evaluating baseline flood processes due to the rapid intensification of the hydrological cycle because of climate change.

Brogan M. Stewart, Sarah E. Turner & Damon Matthews: Climate change impacts on nonhuman primate species based on cumulative CO2 emissions

Climate change is likely to negatively affect the habitats of nonhuman primate species. Recent research has identified a near-linear relationship between cumulative CO2 emissions, and the resulting regional and seasonal temperature increase. We use this relationship to assess the potential impact that cumulative CO2 emissions could have on the range areas available to primate species. We used data from the IUCN on range areas for 426 species and subspecies of nonhuman primates, combined with spatial climate data from the Coupled Model Intercomparison Project Phase 5 (CMIP5) that represents temperature changes per unit CO2 emissions. We used geographic information systems (GIS) modelling to project, in various scenarios, the extent to which climate change will influence temperature within each primate species' environment. We estimated the portions of each species’ range area where annual average temperatures exceed the pre-industrial seasonal maximum temperatures (PSMT). The tested scenarios were for cumulative CO2 emissions from 0.6 – 2.0 teratonnes of carbon, which correspond roughly to 1-4 degrees Celsius of global temperature increase above pre-industrial temperatures. The regions that are predicted to be most affected tend to be species-rich areas between the latitudes of 20 degrees North and 10 degrees South. For the level of emissions corresponding to a 2°C global temperature increase scenario, 26.1% of all habitat ranges had
temperatures in excess of their PSMTs, and for 8% of species, the entire current habitat was above their PSMT. If future annual average temperatures of an area increase above the PSMT to which a primate species is accustomed, this suggests potential for considerable loss of or compromised habitat for nonhuman primates. Such loss of habitat would be a result of the
emergence of climate conditions that are outside the range of historical experience. Our results point to priority areas for conservation efforts, and the need for future research on strategies to increase the resilience of vulnerable local nonhuman primate populations.

Brian Gallagher, Sarah Geargeoura and Dylan Fraser: Impacts of climate variation on salmonid population dynamics: a quantitative meta-analysis

Salmonid fishes generate billions of dollars in economic activity each year, but there is considerable uncertainty in how different species and populations will respond to future climate change. Moreover, it is unknown how much variation in responses to climate forcing can be attributed to biological differences among populations, physical differences among habitats or confounding factors associated with study design. Despite the utility of meta-analyses for gaining general insights into the biology of salmonid populations, there has not yet been a quantitative synthesis of climate change impacts on growth and abundance in salmonids. In this study, I will update and broaden previous literature search methods to build a comprehensive database that records the effects of temperature and precipitation on salmonid population dynamics across multiple studies. This will provide the most comprehensive picture to date of how climate change will impact the future status of this charismatic group.