Natural Lands Trust Preserve Blog

Mile-a-Minute: Early Detection, Rapid Response

It is too late for Early Detection, Rapid Response (EDRR) in Southeastern Pennsylvania for the mile-a-minute vine (Polygonum perfoliatum). The horse is already out of the barn. When you see it along the roadside, you probably no longer register surprise. It isn't everywhere, but it's getting pretty close.

But it has just started to invade the lower Hudson Valley in New York, and I travelled there to be a speaker at a conference convened to develop a strategy for pushing back the invasion. My role in part was to frighten attendees about the risks of not controlling this plant, and to give an "on-the-ground" perspective of someone who has managed mile-a-minute for over a decade. I related the pattern of invasion we have observed, and despite our thorough efforts, how the populations have continued to expand. (Unless everyone in the region is controlling it, then it is difficult for anyone to control it.)

State or region-wide strategies are needed to manage most invasive species, and I am very pleased to see New York engaged in this kind of effort, particularly so early in the invasion.

Precipitation Records

It hasn’t rained at Mariton since the night of August 31.  We received over 0.80 inches of precipitation during that last week of August.  Some of this moisture was associated with Hurricane Katrina pushing gulf moisture ahead of the low.  We actually ended up with almost 4 inches for the month.

Since then it has gotten very dry.  Vegetation is beginning to wilt in Mariton’s woodland.  Fortunately, it looks as if moisture from Hurricane Ophelia will head towards the Delaware Valley later this week.  Hopefully, it will arrive as a pleasant rain and not a deluge.

Due to the nature of my job, I tend to watch the weather forecasts.  (Maureen and I also air dry all of our laundry.)  I have been keeping rainfall records since I came to Mariton.  Unfortunately, data from the early years were lost when lightning hit my computer during a thunderstorm.  But I still have complete records going back to 1997. 

At Mariton, precipitation for 2005 has been very close to average (based on data from 1997 – present).  This year, the monthly precipitation compared closely to the 8 year average for each month with two exceptions.  In April, we had about 3 inches more than average; and in May we had about 3 inches less than average.  So, those two months cancelled each other out.  At the end of August, Mariton had 1.68” surplus of precipitation for the year, compared to the 8 year average. 

Now, the precipitation here could be quite different from where you live.  My friends, Carole and Virginia, also keep rainfall records and we often compare notes.  One lives in Springtown about 4.5 miles west southwest.  The other lives in Raubsville about 2.5 miles to the north.  Mariton’s precipitation is usually within a few hundredths of an inch from one or the other.  But there are many times, especially during thunderstorm season, when all three locations differ by several tenths.  Generally, Mariton will fall in the middle, but not always. 

Tree Cookie Quiz

These tree “cookies” were taken from two trees of the same species, same forest; in fact only a few yards apart.  Can you guess which one is older?

This is a picture of Jamie Leary taken at our Nature Day Camp.  Jamie did an excellent presentation at Day Camp on our forests.  He works for the Department of Conservation and Natural Resources (DCNR) in the Bureau of Forestry.  Jamie is the Service Forester for Northampton and Monroe couties.  He wears various hats in that position, but one of his main duties is working with land owners.  If you have questions about your woodlot or forested land, your first call should be to your Service Forester.  His professional advice is free!

Jamie, like the other Service Foresters, is a wealth of knowledge.  Contact him if you are wondering  what you can do to make your forest more attractive to wildlife, or yield more firewood, or if you notice a tree disease.  Forest owners are often approached by loggers, and amazed at how much the timber is worth.  But before you sign any contracts, contact your Service Forester.  Remember his experience is free.  Your Service Forester can walk you through the contract and help you make sure that the forest cutting is managed to your goals, and not the logger’s.  Even if you never plan to harvest your timber, you should make an appointment to walk your woods with your Service Forester.  They see interesting things that are important to your forest’s health.  Besides, it is a lot of fun to walk through the woods with them, to see the forest through their eyes.

Back to the tree cookies.  The smaller one is older.  It was 29 years old; the bigger tree was 26 years old. 

You will often hear people say that you need to cut out the big trees to let light in, so the younger trees can start growing.  Not necessarily so.  These two trees were about the same age, and one was much better at utilizing resources than the other one.  Before you knew their ages, you might have cut the bigger tree to allow space for the smaller one to grow.  But the smaller (older) tree will probably never reach its potential.  If you leave the bigger one, it can drop acorns and pass its genes onto the next generation of forest.  And I learned that from my Service Forester.

My thanks to Carole Mebus, who took these photos, and many more, to document our Nature Day Camps.

Counting Butterflies

It was a great day to count butterflies.  We had a good group of counters, with a couple seasoned veterans.  Then, we had a couple folks like me, who know a handful of species, but struggle with the different skippers (they look too similar and fly too quickly).  I was really pleased to identify a southern cloudy wing correctly.  That means that there is hope for everyone! 

We tallied 21 different butterfly species, and counted 172 individual butterflies.  We had several that got away before we were able to identify them.  We don't use nets, but rather binoculars that can focus to a few feet.  We have counted 22 species on three previous counts, so 21 is a good count. 

Great spangled fritillaries were the high species with 55 butterflies.  It is a long name, but they are beautifly butterflies that are abundant at Mariton.  When their wings are closed, you can see the silver spots (or spangles).  When open or flying, you see orange.  We only counted 45 cabbage whites.  Silver- spotted skippers came in at 14.

Like bird censuses, a butterfly census is only a snapshot in time.  If we counted in the afternoon, we might pick up some different species and loose some species from the morning count.  In a year with lots of milkweed blooming, we would get different numbers, than a year with very few blooms, etc.  But over years it does give us an idea of what butterfly species one should be able to find in late June.  So, it provides important baseline data.  This can be interesting when looking at trends, more than comparing one year against another. 

Here is a photo of a hackberry emperor.  These are “friendly” butterflies, readily landing on people and light colored clothing. 

What is a Weed?

Or, why am I relatively unconcerned about dandelions in my lawn, and yet very upset about invasive species taking over woods and meadows throughout our region?

A weed is simply an undesirable plant: a plant that is growing in the wrong place. Most likely the plant is unwanted because it grows too aggressively, is unattractive, or has some other negative impact on the landscape or ecology.

Dandelions (Taraxacum acaule, above) have beautiful flowers. It's when the stalks going to seed rise above the lawn that the turf looks terrible. Sure, I worry what the neighbors think. But it only looks bad for a week or so. A lawn is not a natural state of vegetation—turfgrass is not native and woods and meadows are our natural flora—and so having weeds in it is purely an aesthetic objection. I can overcome this by learning to live with it. Really, controlling dandelions is not worth the risk and effort of the pesticides that so many people use.

On the other hand, plants that are invasive in natural areas have the capability of changing the kind of world we live in—reducing us from a diverse native forest to one that is degraded and less complex. Invasive species outcompete others; we risk living in a world where only the thugs have survived. That's five-leaf akebia (Akebia quinata) above, reaching into powerlines.

Humans have introduced thousands of species to new habitats, either on purpose or by accident. This rate of introduction is orders of magnitude greater than what would occur naturally. A fraction of these have later been discovered to be invasive in their new habitat.

The introduction of species appears to bring new bounty to our landscape. But as Kim Todd writes in "Tinkering with Eden: A Natural History of Exotics in America" (Norton, 2001) there are unintended consequences. She writes about the introduction of non-native game species as one example: while these stories “. . . appear tales of addition, subtraction is the underlying theme . . . Instead of a world with heath hens and ring-neck pheasants, we have only ring-necked pheasants . . . Instead of a world with passenger pigeons and rock doves, we have only rock doves . . .” (p.252).

If we are successful controlling invasive plants on our preserves, our lands will be merely . . . less invaded. However, they will also be greater reserves of biodiversity. It is thankless work, this controlling invasives plants this summer (and every summer). People don't tend to notice the absence of something like the increasingly ubiquitous mile-a-minute; they don't know whether it hasn't invaded here yet, or that we spend a great deal of effort keeping it from becoming established (the latter is true). But the stakes are high—either do what we can to minimize the impact of invasive species, or we'll pass on to later generations a world that lacks many of the species we enjoy.

Primitive Plants

We know that ferns were around with the dinosaurs, based on fossil records, and are little changed today. Other plants, the so-called fern allies, also hail from that age and are botanically distinct from the flowering plants that evolved later.

Scouring-rush (Equisetum hymale) does not grow naturally at this preserve (though it can be found nearby at our Stone Hills Preserve). The common name is hyphenated above, implying that it is not a true rush, though perhaps it resembles one. Its leafless stems are filled with an abrasive silica--at one time they were used for scouring pots and pans. I planted some in my garden as a curiosity, a gift from a fellow gardner. She didn't tell me how much it spreads! I wish I'd planted it in a sunken container to confine it. You've been warned.

Field horsetail (Equisetum arvense) is closely related, but is branched into fine leafless stems, making it look grassy or hairy. It is common in wet fields and roadside ditches, where it can be found at Crow's Nest. These fern allies do not flower and set seed; like a fern they release single-celled spores that grow into a tiny organism called a gametophyte, where the reproductive processes analagous to a flower's take place.

There are a number of other fern allies, such as clubmoss and ground pine. This is common clubmoss (Lycopodium clavatum) whose evergreen stems and leaves brightened the monochrome late-winter woods.

Migratory Bird Census

This morning, we conducted Mariton’s 13^th Annual Migratory Count.  We tallied 53 species and 229 individuals.  Fifty-three species is the fourth highest count (the average is 49 species).  The average number of individual birds for the 13 counts is 256 individuals. 

Mid-May is near the peak of migration, when one can see the most species.  Most birders are saying that the warbler migration has been slow this spring, and I would agree.  We counted 14 warbler species in 1999 (the year with the highest species count); this year we counted 10 warbler species. What is really noticeable is that the number of birds seems down, at least for some species.  On the bright side, we may be in for a stretched-out warbler migration.

I would like to thank Bill Wallace, Virginia Derbyshire, Carole Mebus and Anne Hogenboom for volunteering their eyes, ears, and knowledge.  The census would not be as thorough without dedicated volunteers.  Plus, I really enjoy their company.

Here is a sampling of the some of the birds that we counted this morning (the complete count is posted in the Nature Center):  black-billed cuckoo, 6 black-throated blue warblers (that is a lot), Blackburnian warbler, chestnut-sided warbler, 16 ovenbirds, and 9 rose - breasted grosbeaks.  We spotted a great blue heron flying overhead, and yes we counted it.

We will be doing a Nesting Bird Census on June 4.  There probably won’t be as many species (although this year may be different), but it will certainly be interesting.  Bring your binoculars and help us count the birds! 

After the Flood

On April 4 (see April Flooding), I posted 3 pictures taken from the  River Lookout trail, and at the base of the cliffs.  Shown  here are photographs taken from approximately the same locations, after the river returned to its banks.  The river is still high, but you can imagine the impact of the flood by comparing the photos.

 

Finally, here is a picture of Tom Kershner (on the right) and Rebecca Shields Moose standing on Route 611, beside a section of the wall.  We took advantage of the road closure to cut some trees that I felt could compromise the integrity of the stone wall.  The flood waters actually topped this section of wall, which is 7 feet above the road surface.  Tom is the Preseve Manager at Gwynedd Wildlife Preserve, and is also Natural Lands Trust's arborist.  Rebecca is one of four Stewardship Assistants.  These folks visit the different preserves and help Preserve Managers "get the job done".

Fresh snow

We received 7" of snow from the latest snow storm.  Melted down, it netted 0.78" of precipitation.

The parking lot is plowed, the sidewalks shoveled and trails are ready for exploring.  Sunnyside Road is plowed, and passable, although there are still some slushy spots.

The Carolina wren has been very active at the suet blocks.  These late storms can be pretty hard on the Carolina wrens.  A few winters back, abundant C. wrens disappeared after a late storm.  It was few years before we began to see them again.

I think it is time to put on the snow shoes and check the trails.  There should be a some animal tracks to invesitgate.