Chapter 6 Discussion
While the results of this study indicate that wetlands influence the recovery of vegetation in a post fire landscape, it is unclear the exact methods in which they do so. NDVI values in the wetlands for this study return to values like pre-fire quicker than the non-wetland areas. However, this return to pre-fire greenness does not indicate whether the landscape has returned to pre-fire conditions in terms of its ecology. Since the fire occurred in 2002 it is very likely that the vegetation that occupied the landscape pre-fire has not come to completely reinhabit its pre-fire distribution in the area. The lack of consideration for vegetation type on the landscape pre- and post-fire means that the type of recovery happening cannot be known.
One large constraint of this study was that the selection of wetlands was done manually. A large improvement would be the implementation of automating the selection of points so that they are more random. This development of random selection would not only improve the statistical analysis but also allow for analysis of more areas. Similarly, the variation between different wetland types may be hindering the results of this analysis. Given that freshwater emergent and shrub/forested wetlands likely have different vegetation types and hydrologic regimes it would be important to evaluate their vegetation recovery patterns as independent from one another.
The results of this study indicate that further analysis would shed light on the integral differences in recovery rates. The use of an auto-regressive integrated moving average (ARIMA) or a first order auto-regressive model, like that used by Thomas et al (2022), would help to describe the rates of recovery, expected long-term ecological state, and probability of recovery at other sites. Along with this analysis of wetland hydrology, biogeochemical cycling, and vegetation composition in these locations would provide an idea of the ecological implications of wetlands on post-fire recovery. Similarly, wetlands in other fires would need to be studied as well to see how variable the vegetation recovery might be. Severity is also a key factor that wasn’t fully considered in this analysis. While the transects outside the wetlands were in burn areas, the severity of burn has massive impacts on the landscape and in turn would almost certainly impact how wetlands influence the recovery rate.
Another essential element to take into consideration for further analysis is climate change. Climate change plays an integral role in fire disturbances in Colorado such as the Hayman fire. As climate change makes fires more frequent and severe, so does it impact the ecology of these wetlands and how they respond to disturbances. While these disturbances have devastating impacts on the landscape, they also provide a unique opportunity to study their effects. This study analyzed one of the many ways in which wetlands respond and assist their surrounding landscape. The use of tools like NDVI is extremely helpful but not adequate in fully understanding the role of wetlands in post-fire vegetation recovery. Continuing the study and analysis of wetlands could be integral to assisting vegetation and landscape recovery in many areas affected by fire.