Effects of forest windstorm disturbance on invasive plants in protected areas of southern Illinois, USA

Abstract

1. Invasive plant populations respond positively to light increase from windstormcaused canopy damage, but are typically out-competed over time as the tree canopy recovers. Some invasive plants have the ability to slow or even completely prevent canopy regrowth. It is important to understand invasive plant dynamics in windstorm blowdowns to inform effective forest management. We hypothesized that blowdown areas are more invaded than unaffected forest and that invadedness of a blowdown will decrease with increasing time since disturbance and increase with disturbance magnitude.2. We used Landsat imagery to identify 31 blowdowns caused by one of three storms in southern Illinois of the United States: 2006 tornado, 2009 derecho or 2017 tornado. We statistically matched these blowdowns to areas of unaffected forest based on slope, aspect, elevation, distance to a road and distance to a trail.We surveyed blowdown and unaffected units for invasive plants in summer 2018.Disturbance magnitude was measured in two ways: per cent change in normalized difference vegetation index (NDVI) and area of blowdown.3. Overall, blowdowns were more invaded than their statistically matched areas.Invadedness of blowdowns decreased with increasing time since disturbance, indicating that the blowdowns are recovering as tree canopy regrowth shades out invasive plants. Per cent change in NDVI was not a supported predictor of blowdown invadedness, but invadedness was strongly positively related to blowdown size. Larger blowdowns recover more slowly than smaller disturbances due to different recovery pathways, providing more time and opportunity for the spread and establishment of invasive plants. Synthesis.Our findings suggest that although blowdowns contained higher cover of invasive plants than forest unaffected by windstorms, invasive plants were responding negatively to canopy regrowth. Land managers should prioritize treatment of invasive plants in larger and more recent blowdowns. K E Y W O R D S blowdown, canopy disturbance, derecho, Elaeagnus umbellata, Illinois, Landsat, Lonicera japonica, tornado S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Daniels MK, Larson ER. Effects of forest windstorm disturbance on invasive plants in protected areas of southern Illinois, USA.

Asiatic bittersweet presence and cover over 20 years in upland hardwood forests after hurricane disturbance

“…Our bittersweet cover model predictions mirrored those of other investigators, including Daniels and Larson (2019), who found increases in invasive shrub and liana cover with time and gap creation. As with our presence model, our cover model findings support gap partitioning by direction from center; cover increased west of centers within gaps, but we found no definitive differences in cover north or south of centers.…”

“…Experimental studies that manipulate coarse woody debris cover would yield better determination of the effects of debris on bittersweet colonization. Unlike the findings of Daniels and Larson (2019), we did not observe increases in cover with gap areal size. We attribute this to the large size (all gaps were .…”

“…However, the rate of presence increase declined substantially between TIME 9 and TIME 20 in our study. As Daniels and Larson (2019) and Khaniya and Shrestha (2020) found with multiple invasive species, bittersweet spread in our study slowed because of increasing tree canopy cover (Appendix) that reduced available light. Our results concurred with those of other investigators: The probability of finding bittersweet increased within wind-created forest gaps compared with outside gaps (McNab and Loftis 2002).…”

From eDNA to citizen science: emerging tools for the early detection of invasive species

“…Daniels and Larson () demonstrated how remote sensing can be used to map disturbances like forest blowdowns (a) before and (b) after tornadoes or other wind storms. (c) These disturbed patches may be priority sites for monitoring biological invasions, including non‐native understory plants.…”

Rapid Assessment of Tree Damage Resulting from a 2020 Windstorm in Iowa, USA

“…Natural disturbances cause extensive damage and mortality to trees in forested ecosystems, and as a result, may also accelerate or reinitialize forest successional pathways, and help establish a mosaic of stand age and stand structural classes on the landscape [1][2][3]. These changes can be beneficial to particular wildlife species but can also enhance the proliferation of insects, diseases, and shade intolerant invasive plants [4]. The frequency of forest disturbances appears to be increasing in the midwestern portion of the USA, particularly weather-related disturbance [5].…”