Background
Previous studies have found that peatlands are ecosystems critical for global carbon storage since their waterlogged conditions reduce the decomposition of organic matter (Glaser, 1987). The two types of peatlands, fens and bogs, provide habitat for a wide range of adapted vegetation, primarily bryophytes, which are important carbon sicks (Bubier et al., 1995; Glaser, 1987). However, ground water extraction by industries in Northern Alberta and the NWT have the potential to lower peatland water table levels. Organic matter decomposition rates can increase in aerobic conditions; thus, it is important to conserve peatland hydrology to prevent their conversions into carbon sources (Dunn & Freeman, 2011; Lin et al., 2019). Furthermore, dry peatlands may be at a heightened risk for wildfires as peat can be a fuel source for fire and is prone to long lasting smoldering combustion (Rein, 2013). Since saturated peatlands provide ecosystem services like carbon sinking (Glaser, 1987; Nenzén et al., 2020), it is imperative to understand how local alterations in water use may influence peatland fire severities and the subsequent regeneration of bryophytes critical for peatland resilience.
The purpose of our study has two main objectives:
1.
To study how the water table levels of a peatland can impact the potential fire severity as fire can heavily impact the ecosystem function of peatlands (Lugo, 1995) and groundwater extraction of peatlands is common (Kopp et al., 2013).
We hypothesize that low water table levels (occurring naturally and through ground water extraction by industry) will lead to drier peatlands and therefore increase fire severity of wildfire in those peatlands.
The results of this objective would allow us to decide whether guidelines should be put in place on how much groundwater can be extracted between different industrial sources in areas where peatlands are prevalent on the landscape. Industries that extract groundwater and impact the water table of wetlands could include agriculture, forestry, and oil and gas. We plan to use the findings of how hydrology may impact fire severity in peatlands to provide fire managers with thresholds of safe and unsafe water table levels in terms of fire risk.
We hypothesize that low water table levels (occurring naturally and through ground water extraction by industry) will lead to drier peatlands and therefore increase fire severity of wildfire in those peatlands.
The results of this objective would allow us to decide whether guidelines should be put in place on how much groundwater can be extracted between different industrial sources in areas where peatlands are prevalent on the landscape. Industries that extract groundwater and impact the water table of wetlands could include agriculture, forestry, and oil and gas. We plan to use the findings of how hydrology may impact fire severity in peatlands to provide fire managers with thresholds of safe and unsafe water table levels in terms of fire risk.
2.
To study the impact different fire severities have on regeneration of bryophytes in peatlands to see how the impacts our objective 1 will have on peatland resilience and recovery.
We hypothesize higher fire severities (expected from our objective 1 as a result of lower water tables) will decrease the success of regeneration of bryophytes.
This plant group is an important part of fen ecosystems and diversity (Mälson & Rydin, 2007). In our changing climate and with more frequent impacts to local hydrology from land use changes and developments, the results of this objective could be applicable to how we manage fire in peatlands when considering their protection as important carbon sinks (Lin et al., 2019; Liu et al., 2010). We hope to use this scope on regeneration to inform fire managers with guidelines on how to control fires of differing severities in the context of peatland resilience and protection as carbon sinks.
We hypothesize higher fire severities (expected from our objective 1 as a result of lower water tables) will decrease the success of regeneration of bryophytes.
This plant group is an important part of fen ecosystems and diversity (Mälson & Rydin, 2007). In our changing climate and with more frequent impacts to local hydrology from land use changes and developments, the results of this objective could be applicable to how we manage fire in peatlands when considering their protection as important carbon sinks (Lin et al., 2019; Liu et al., 2010). We hope to use this scope on regeneration to inform fire managers with guidelines on how to control fires of differing severities in the context of peatland resilience and protection as carbon sinks.
Expected results
Fire requires dry fuel (Nolan et al., 2016) and peatlands are characterized by the first 40cm or more of its top layer being peat which has significant water retention capabilities (Glaser, 1987; Huang et al., 2015). When peat moisture levels are low, it is susceptible to smoldering and ignition (Huang et al., 2015). Therefore, in terms of our first objective we are expecting that low water table levels will correspond with higher fire severities as recorded by the depth of burn, a hypothesis consistent with Nelson et al. (2017) and Rowe et al. (2017). An alternative to this result could be no relationship, or fire severity increasing with increased levels of water table levels. No relationship could be a possibility since other measures of moisture before fire, such as relative peat moisture, may have a stronger influence. If high severity fires are correlated with low moisture levels in the peatlands, this information could help fire managers make both ground water draining limits and decision-making outlines for fire suppression in order to protect peatlands from severe fires.
We would expect that with higher fires severities, more peat gets consumed as a fuel. Since peat has such high water retention capabilities (Huang et al., 2015) we would expect that less peat on the landscape would mean less water available for plant regeneration. For our second objective, we are expecting that more severe fires would increase the length of time for regeneration of bryophytes. Previous studies have found that fires tend to not have long term effects on bryophyte regeneration, Sphagnum spp. recolonizes quickly and late colonizing species should be abundant by 5 years post fire (Magnan et al., 2012). Since wildfires generally always impact biodiversity and ecosystem services to varying degrees (Thom & Seidl, 2016), no relationship between these two variables seems unlikely, but is possible if our dataset is not representative enough of different levels of fire severity. High fire severity correlating with shorter regeneration time is unlikely since fires use peat as fuel and consequently reduce water availability. The findings from this objective can help inform managers on peatland recovery time to help them make decisions on whether or not or how to control peatland fires for their protection.
We would expect that with higher fires severities, more peat gets consumed as a fuel. Since peat has such high water retention capabilities (Huang et al., 2015) we would expect that less peat on the landscape would mean less water available for plant regeneration. For our second objective, we are expecting that more severe fires would increase the length of time for regeneration of bryophytes. Previous studies have found that fires tend to not have long term effects on bryophyte regeneration, Sphagnum spp. recolonizes quickly and late colonizing species should be abundant by 5 years post fire (Magnan et al., 2012). Since wildfires generally always impact biodiversity and ecosystem services to varying degrees (Thom & Seidl, 2016), no relationship between these two variables seems unlikely, but is possible if our dataset is not representative enough of different levels of fire severity. High fire severity correlating with shorter regeneration time is unlikely since fires use peat as fuel and consequently reduce water availability. The findings from this objective can help inform managers on peatland recovery time to help them make decisions on whether or not or how to control peatland fires for their protection.