Fire: a hot topic which often gets a bad rap

On Wednesday, March 26, 2017 a fire got started in the Point Pelee National Park (PPNP) marsh, the cause of which is as yet undetermined. I have my own theory, as do others. Regardless, the fire was allowed to burn itself out, with park staff and local firefighters successfully protecting the boardwalk. From some media reports, I believe the area burned was about 125 hectares.

Kory Renaud posted a few pics on his blog which you can see here.

There was lots of local media coverage, including social media, and it was interesting to read all the comments of concern in how horrible this was for the marsh and the wildlife. Of course it is encouraging to know that so many people have concerns for wildlife and natural areas. Unfortunately people have been programmed, it seems, to believe that fire in a natural area is always devastating.

Some people will remember the Smokey The Bear ads and posters, declaring that "Only you can prevent forest fires", or have seen other posters showing a firefighter rescuing little bambi from a forest burning in the background.

There is no question that fire can have a significant impact on a natural area. But it is imperative to remember that fire is a natural aspect of many natural areas, and in spite of the effects it might have on some species or individuals, contributes in a positive way to the overall health of the ecosystem.

Remember the fires of Yellowstone National Park in the late 1980s? It was initially declared a national disaster by the masses. Some people knew better. In short order, it was shown how critical periodic fire is to the broader ecosystem, and without it, future fires can be a lot more devastating. There were photos showing bison grazing peacefully in the meadows, while smoke lingered in the background. Wildlife in general were not nearly as alarmed as people were. The event which had so much attention provided an opportunity to inform the masses of how necessary, and beneficial, fire can be. (These next two images were not taken at the time of those fires.)

Bison resting at Yellowstone National Park

The same kind of thing has happened, albeit on a much smaller scale, with the recent fire at PPNP. There was a 'firestorm' of comments posted to various media, some of them which were quite concerned about how devastating it would be to wildlife, such as the recently emerging frogs and turtles. Supposedly the marsh would never be the same. Admittedly there is the possibility that a very small number critters might have been impacted, but far, far fewer than people might realize. And in reality, fire is an essential component to maintain healthy natural ecosystems, including marshes, certain types of forests and in prairie and savanna. In one sense, fire is perhaps more important nowadays in marshes than it was in decades gone by.

Let me explain.

One of the most common species of plants typically found in many marshes is cattail (Typha). Yet the cattail we see in our marshes these days is not the same cattail that used to dominate. The native species is Wide-leaved Cattail (Typha latifolia). Unfortunately there is a similar looking species that is native to Europe and Asia and arrived decades ago, known as Narrow-leaved Cattail (Typha angustifolia). The two of them hybridize, and the hybrid is known as Typha X glauca. Unfortunately both the non-native species and the hybrid are quite aggressive, and quickly dominate most marshes they occur in. They grow thicker and taller than the native cattail. A stand of cattail these days, is very dense, and has fewer benefits to wildlife than in days gone by.

A really healthy marsh which supports a greater diversity of plants and wildlife is referred to as a hemi-marsh, which really means that it is about half emergent vegetation such as cattail, and half mostly open water which may include things like water lilies floating on the surface. There are lots of edges, where the emergent vegetation and open water intersect, and that is the most critical area for many species of wildlife.

Virginia Rail using the edge

This first image shows a relatively healthy mix of open water and emergent vegetation at St. Clair NWA.

This next image shows what the south end of the Rondeau marsh looked like in the mid 1980s, where there was a good mix of emergent vegetation and open water. The amount of open water is exaggerated a bit, since I used a 24mm wide angle lens.

The areas that are open at the beginning of the year, may gradually get partially covered over by floating vegetation such as water lilies, and this provides shade for the water, making the metre or so depth of water below a more suitable temperature for fish, frogs, and millions of invertebrates, etc to survive in during the hot summer months. All of these creatures are essential for the survival of many other forms of aquatic life. For example the under surface of the lily pad is where some invertebrates such as snails attach. Birds such as rails, with their long toes, can walk on top of these lily pads and will turn up the pad to feed on the invertebrates.

The seeds of the lily pads as well as for many species of submergent pond weeds (Potamogeton species) are invaluable food sources for migrating waterfowl.

When the non-native cattail and hybrid cattail dominates, it steadily fills in the openings of a healthy marsh, suppressing the sub-mergent vegetation and making the area generally less beneficial to wildlife and other native plants. Many marshes today are dense, with very little open area amongst the cattail. This next photo shows a very dense stand of cattail, with the only open water actually not directly associated with the marsh, but is part of the deeper water of Rondeau Bay.

If a wetland is impounded, that is, surrounded by a dyke system and the water levels can be controlled via a pumping system, one can raise the water level to slow down the advance of these dense stands of cattail. The PPNP marsh is not impounded, with a dyke only at the north end, so it is subject to the natural fluctuation of water based on adjacent lake levels.

In lots of cases, the expanding stand of non-native cattail is not rooted to the ground; the roots and thatch build-up can create a dense floating mat of vegetation, sometimes a metre or more thick, which floats over water too deep for it to take root in. Fire, however, can reduce the thatch build-up and kill off the expanding edges of these floating mats, suppressing the expansion and giving the open areas of water a chance to survive. It also burns the buildup of dead plant material which has accumulated over many previous years, exposing the organic material at 'ground' level. The plants themselves, whether it be cattails or others, will for the most part not likely be harmed. They will survive, since the growing points have been underwater and thus have not burned. But the outer edges of these mats may be slowed down in their expansion.

As for the concern over wildlife: there are few, if any, birds nesting yet, so nests and young will not be affected. Adult birds can fly, so they can escape. Frogs and turtles, if they feel threatened, will simply go underwater until the fire has passed. And in reality, there were probably very few frogs or turtles in the dense stand of cattails....it was likely too dense for them to use. They were likely at the edges or in the open water basking on hummocks when the fire approached, so they could easily plop into the water and escape. Mammals such as muskrats will also be able to escape by going underwater.

Likely the only types of wildlife to be affected may be the larvae of certain species insects which may have overwintered in the stalk of the cattail.

As for the benefits of fire:
-it will likely open up the dense stand of cattail, making more edge around open water which is where most of the wildlife prefers; they can get out into the open water, yet if they feel threatened from avian predators such as a Northern Harrier (marsh hawk), can retreat to the denser vegetation;
-the surface of the now exposed organic matter will, for a few weeks, have some water on the surface or at least be moist, which will attract frogs as well as shorebirds and members of the heron and egret families;

 

-if there were muskrat houses in the cattail stand, they will be exposed and potentially be a nesting site for Black Tern, a species at risk ranked as Special Concern;

-an exposed muskrat house can also serve as a basking area, as well as a place to lay their eggs, of turtles, including the Endangered Spotted Turtle;

-where open water and emergent vegetation meets, reeds such as bulrushes (Scirpus sp) may grow, and this is a favourite spot for the Threatened Least Bittern to nest.

So please keep in mind that fire is natural and beneficial to ecosystems and wildlife. Take a walk on the boardwalk (no this isn't an advertisement for a Monopoly game :-) over the next few months and watch how the marsh and wildlife responds.

Ancient hieroglyphics, or???

If you are out and happen to see these patterns on a barkless tree trunk, you might wonder just what has created this.

It isn't some form of ancient writing, of course, but the markings of a non-native and highly invasive insect known as the Emerald Ash Borer (EAB).

The EAB is a metallic green beetle that is native to Asia. The consensus is that it arrived in North America via wood packing material, which isn't surprising in many ways due to the huge volume of things that North America purchases from Asian countries. It was first detected in Michigan in the late 1990s, and shortly afterwards, expanded into southern Ontario, being first detected there at Windsor.

The EAB specializes in feasting on ash (Fraxinus spp) trees. In its homeland, it is not considered a major problem since the ash species there apparently have built-in resistance. However North American ash trees do not have that resistance, and so are quite vulnerable. The adult EAB feeds on the leaves and are not all that destructive, but the larvae burrow under the bark, feeding on the woody material immediately under the bark. This is where the critical transfer of sap and nutrients to feed the tree takes place, and the larvae's burrowing and feeding action cuts off the flow. In fairly short order the upper part of the tree dies. The roots may still be alive and there may be some subsequent sucker growth of the tree, but it will likely never grow to a mature specimen.

The EAB has quickly spread in less than two decades to many provinces and states around the Great Lakes and points farther east. The travel of adults to colonize new areas is facilitated by wind, so the prevailing westerly and southwesterly winds cause eastward spread more quickly than westward spread.

Ash trees are a major component of eastern deciduous forests. Or at least they used to be. There are several species of ash occurring in southern Ontario: White Ash, Red Ash (and its varietal form, Green Ash), Black Ash, Blue Ash and the only 'non-colourful' one, Pumpkin Ash. All species are susceptible to the EAB, although it has been surmised that Blue Ash is somewhat more resistant.

Due to the aggressive nature of the EAB most forests in southern Ontario, and especially southwestern Ontario, have been devastated, and dead ash trees are now dominant. But given the brittle nature of standing dead ash trees, many are now snapping off and if they don't get hung up in an adjacent tree, come crashing to the ground. Every moderate to severe wind storm brings more and more down.

The main reason for the preceding discussion is that over the past few weeks I have had quite a few comments and questions directed my way regarding the apparent unsightly mess along the roads and trails of Rondeau Provincial Park. The mess is actually the result of the attention being given to the thousands of dead ash trees.

So many falling trees are a hazard, to people, to vehicles and to the structures in the forest. This next image shows a couple of trees that came down and not only blocked the trail, but also did some major damage to the information sign along the trail.

 This next image shows a repaired boardwalk structure along the Tuliptree Trail, which was heavily damaged when a dead ash tree fell on it.

There is currently a major effort to take down the myriad dead ash trees along the roads and trails, in a controlled manor rather than waiting for the next few wind storms. As a result, the road sides and trails look a bit unsightly, to be sure.

This next image shows one of my favourite views along the Tuliptree Trail, taken in April, 2014.

Now it looks like this next photo, so the nice clean appearance of the above photo will take a few years to get back to.

For anyone planning to visit Rondeau in the next few weeks, scenes like this will be commonplace, but please bear in mind that it is a temporary appearance. The dead ash trees will decompose fairly quickly in the next few years. The freshly cut stumps will gradually weather and blend into the background, and with the growing season beginning in May, the greenery will cover up the messy look to some extent.

Major changes to the forest are a periodic occurrence. In some forest ecosystems, fire occurs periodically, killing trees and shrubs that are not resistant to fire. In other forest ecosystems, major wind storms or ice storms cause significant changes. At Rondeau, I can remember several such events:
-a huge ice storm in March of 1976, where many trees or major limbs came crashing down and virtually every tree in the park was affected;
-major winter blizzards with high winds occurred in late January of 1977 and 1978, causing major damage;
-more recently was the major downdraft of July 1998 that caused considerable damage to many trees (and structures).

Admittedly the outbreak of the EAB is not as natural an event as a storm, but the results are much the same. And just as the forest recovered to varying degrees following those other major events, I expect that the forest will recover after the ash trees cease to become a dominant species. But it will never be quite the same.