Signs of Spring 13: Mosquitoes!

D. Sillman

Photo by D. Sillman

As the temperatures start to slowly rise back up into more comfortable ranges, and Signs of Spring give way to Signs of Summer, Deborah’s and my thoughts inevitably turn to pulling out our folding chairs and getting outside in the evening to watch and feel the day come to a close. We usually get most of the month of April and then a good part of May (depending how fast summer really sets in) to enjoy long evenings outside, but by June something comes up that limits our time outside: mosquitoes.

There are always a few mosquitoes right away in the spring, but it takes some time and some continuous warm temperatures for the real swarms to arise. This staged invasion is due to the way that different mosquito species survive the winter.  Our native mosquito species, by the way, don’t seem to be negatively affected by very cold winters or excessively stimulated by very mild winters. They are able to roll with our fluctuating climate and pull themselves back into their reproductive (and blood meal requiring) life stages with great ease and efficiency.

Photo by J. Gathany, CDC Wikimedia Commons

Photo by J. Gathany, CDC Wikimedia Commons

Some of our mosquitoes overwinter as cold resistant eggs while others hibernate as larvae. There are also a few mosquito species that overwinter as mated adult females. These adult females emerge early in the spring and are ready right away for a blood meal so that they can finish making their eggs. They are the first attacking wave in the early spring. Again, cold spring temperatures may delay their emergence, but the cold does not seem to significantly reduce their numbers. So there are a few mosquitoes active as soon as air temperatures get sufficiently warm, but the swarms don’t come until all of those overwintering eggs and larvae mature and begin to seek their blood meals.

There are so many things to say about mosquitoes, and so many different points of view to take about them!

Photo by Abhishek, Wikimedia Commons

Photo by Abhishek, Wikimedia Commons

Dr. Nora Besansky is a biologist at Notre Dame University who specializes in mosquitoes. She was interviewed on NPR back in February and spent most of her on-air time emphasizing how beneficial and important most mosquitoes are. Of the four thousand or so species of mosquitoes less than one hundred actually transmit human diseases. The rest occupy important places in many food chains (for mammals, birds, fish, amphibians, reptiles, and wide range of insects and other arthropods) and also function as pollinators for many species of plants (all adult mosquitoes, Dr. Besansky emphasized, drink flower nectar). Blood feeding by mosquitoes is only carried out by females and is needed to provide the protein and iron required to make viable eggs. The female mosquitoes can take a blood meal from a wide variety of potential hosts. The list of possible hosts, in fact, is nearly identical to the list of what can eat mosquitoes, and different mosquito species specialize on particular types of hosts.

Another perfectly reasonable point of view, though, concerning mosquitoes looks at the nearly one hundred mosquito species that can transmit diseases to and in between people. There are some serious diseases on the mosquito transmitted list! Malaria, yellow fever, Dengue fever, West Nile virus, and a whole slew of encephalitis syndromes are all carried by mosquitoes.  Over the past winter, our awareness of a new mosquito borne virus spreading across South and Central America, the Zika virus, has triggered intense discussions about mosquito control procedure and the safety of travel to Zika affected areas. Each year, according to EB Medicine (an on-line medical reference site), seven hundred million people get a mosquito transmitted illness. Most of these cases occur in human populations residing in tropical and subtropical climate zones, and about half of all of these cases involve malaria.

So here in Western Pennsylvania (which for now anyway, is about as non-tropical or subtropical as you can get!), we have nothing to worry about, right? (I bet everyone reading this can feel the coming bad news that is about to extend this essay!).

Anopheles (Photo by J. Gathany CDC Wikimedia Commons

Anopheles (Photo by J. Gathany CDC Wikimedia Commons

Let’s talk about the mosquitoes that spread some of these diseases: Malaria is caused by a protozoan parasite called Plasmodium. Plasmodium is most commonly spread by mosquitoes of the genus Anopheles. The very good news is that Anopheles mosquitoes, unlike our more robust native mosquito species, cannot survive our long, cold winters and are, therefore, not found in Western Pennsylvania. Fortunately, malaria is not something we have to worry about locally!

Aedes aegypti Photo by J. Gathany CDC Wikimedia Commons

Aedes aegypti Photo by J. Gathany CDC Wikimedia Commons

When we talk about mosquito spread viral diseases, though, like yellow fever, Dengue fever, and Zika, we are especially (but not exclusively) talking about mosquito species that are in the genus Aedes. Aedes aegypti , in particular, is an active, wide-spread tropical and sub-tropical mosquito species and is often the species involved in the transmission of these illnesses to humans. Aedes aegypti has all sorts of specializations that make it very difficult to control. It can lay its eggs in very small pools and puddles of water. Its larvae can develop successfully in the tiniest volume of even the most stagnant water (think rain water collected in a discarded tin can or old tire!), and bacterial growth in these water sources actually stimulates egg development! The adult Aedes mosquitoes are most active at dusk and at dawn especially in shady areas, but they can bite (and spread their viruses) at almost anytime during the day and also at any time of the year. Adults can also live exclusively inside of houses and other buildings often taking their blood meals while the people in these buildings are asleep.

Aedes albopictus Photo by J. Gathany CDC Wikimedia Commons

Aedes albopictus Photo by J. Gathany CDC Wikimedia Commons

So where is the boundary between the temperate and subtropical climate zones? How about 250 miles from here? How about even closer than that? There are established populations of Aedes aegypti  and other Aedes species in Washington, D. C.! There are also periodically occurring populations of Aedes albopictus (the “Asian tiger mosquito”) right here in Western Pennsylvania, and there is some indication that the Asian tiger mosquito is developing a tolerance for our cold winters and may be setting itself up as an established alien species! The Asian tiger mosquito can carry all of those diseases listed above and may represent a significant human health threat!

It is always “good news/bad news” when thinking about these ecological and medical problems. The really good news is that our cold winters limit the ability of these virus and parasite carrying mosquitoes to establish themselves in Western Pennsylvania. The bad news is that these mosquitoes are evolving to get around that limitation and, with the ongoing warming associated with climate change, the climate seems to be meeting the species changes half way! Mosquitoes and ticks, unfortunately, are some of our signs of spring and summer! I will talk about ticks next week in our first “Signs of Summer!”

 

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Signs of Spring 12: Getting Lost in the Woods

Photo by D. Sillman

Photo by D. Sillman

Last Monday Deborah and I took advantage of an open day in our Penn State schedules and headed up to Todd Nature Reserve. The Nature Reserve (formerly called “Todd Sanctuary”) is a rocky, stream crossed, 176 acre site owned and maintained by the Audubon Society of Western Pennsylvania. It is in Sarver in southeastern Butler County and has been, for all of the thirty-three years Deborah and I have lived in this area, one of our favorite places to hike. There are five miles of crisscrossing hiking trails in the reserve. A two mile “Loop Trail” encircles the site’s perimeter and takes you from stream beds to ridge tops and back again through young to middle-aged hemlock stands and a variety of mixed hardwood forests. Shorter trails (with evocative names like “Hemlock,” “Indian Pipe,” “Pond,” “Warbler,” and “Polypody”) interconnect fern capped rock cities with densely vegetated copses with the human constructed pond (built in 1969).

There were no other cars in the gravel parking lot, so we knew that we would have the reserve to ourselves.   Our plan was to do the Loop Trail and keep our eyes open for both birds and wildflowers.

We walked up to the cabin and picked up a new copy of the trail map and then crossed the poison ivy rich clearing to enter the dark, cool hemlock forest. The red blazes of the Loop Trail took us to the right, and we walked up and over some rolling terrain in the deep cover of the hemlocks taking care to watch each footfall on the very irregular, rocky surface.

There are few decisions to be made while walking these trails. The paths are well worn and the blazes are always clear. Occasionally you need to jog around a fallen tree or bypass a muddy low spot, but it is not really possible to get lost.

Which is a shame (and it is also, to quote Anton Chekhov, the proverbial “gun hung on the wall” in Act 1!).

The times that Deborah and I have been lost on hikes, while not too very numerous, are times that are very vividly etched in my memory! There is some type of primal reaction, an instinctive intensity that rushes over you when you realized that you are out in the middle of an unknown area with no clear idea of where home (or your car) or help of any kind might be!

Mt. Marcy Photo by D. Tripp, Wikimedia Commons

Mt. Marcy Photo by D. Tripp, Wikimedia Commons

I remember being lost up in the Adirondacks while on a backpacking trip with our grad school friends, Mark and Terre. We were hiking up around Mt. Marcy and were enjoying a beautiful, sunny, early May day after post-holing our way across the lingering snow fields higher up on the mountain. Walking was easy and talking was even easier. All of sudden we realized that we were on a trail that had no blazes. We consulted our maps and could not make any sense of the terrain around us and the topographic detail of the map! We also realized that we didn’t have a compass and so were guessing at directions. There was nothing to do but follow the trail back.

We hiked a good mile or two back along the trail getting more and more anxious about where we were and where we were going to end up. Finally, we found a turn blaze that we had missed and were back on our trail and back on our map.

The feeling you get when you re-find your trail, when you see your blazes again is incomparably wonderful! Almost worth the anxiety that led up to it!

When Deborah and I hiked the Baker Trail a few years ago we also lost the trail a couple of times. One time we were able to use our maps and compass (I always carry a compass now!) to bushwhack across a field and forest stand to regain the trail. Another time we ended up wandering around on an active strip mine for several hours (because the trail blazes we were trying to find only faced one direction! They could not be seen when approaching the trail from an off-trail location!). Another time, we crossed a trail section that was being redesigned and the familiar yellow, Baker Trail blazes had not yet been placed (we wandered around for quite a while until, with great joy, we found a rectangle of bright yellow paint on an old black cherry tree!).

Anyway, you can’t get lost on the Todd Nature Reserve Trails (or so I thought!).

Photo by D. Sillman

Photo by D. Sillman

Along the Loop Trail there were abundant wildflowers. The broad, flat, parasol-like leaves of Mayapple (Podophyllum peltatum) spread out alongside the trail. Most of the plants had not yet opened their white flowers. Compared to previous years, the Mayapple seems to be developing a week or two later this year!  Trillium (both the large flowered white and the red) are still in bloom here, too. On most of the trails closer to our house the trillium flowers have faded and fallen. The “season-time” here is a week or two behind our local ecosystems.

Multiflora rose is growing in scattered patches that are getting larger every year. Garlic mustard is also becoming increasingly abundant. These two invasive species have the potential to do a great deal of harm to the native plant species in the Reserve. As I talked about last year, the impact of the garlic mustard extends to its stresses it exerts on the soil fungi that many plants (like Mayapple) require to flourish.

Photo by D. Sillman

Photo by D. Sillman

There is a very nice array of native plants in flower: mitrewort, dwarf ginseng, clintonia, jack-in-the-pulpit (pictured to the left), Solomon’s seal, wild geranium and many more (Deborah listed twenty flowering species in her notes!). Ferns are also abundant along the trail including Christmas fern, evergreen woodfern, New York fern, sensitive fern, interrupted fern, hayscented fern, cinnamon fern, and rattlesnake fern (one of Deborah’s favorites). There is also an abundance of raspberry and blackberry canes growing along the trail.

We also met up with a very belligerent eastern garter snake (Thamnophis sirtalis sirtalis) on the now seldom used trail that goes to Inspiration Point (a formerly cleared spot the overlooked the deep ravine cut by Watson Run). The snake, who tried very hard to

Photo by D. Sillman

Photo by D. Sillman

convince us of his ferociousness by coiling up into a tight ball and lunging at us with an open mouth, seemed very put out that we didn’t immediately flee. We walked past him and went on to the point. He was slithering away when we walked back past a few minutes later!

As we approached the end of the Loop Trail and were getting close to the Cabin and the walk back up to the parking area, we saw a set of signs marking a newly completed trail called the Shoop Trail. This trail was not on our map, but the sign described it as a 0.9 mile loop, so we decided to give it a try.

The first part of the Shoop Trail was through a young hardwood forest. The path was firm and dry and the wildflowers abundant. The second part of the trail dipped down a bit into a spring fed swale and the trail became muddy and ponded over and very difficult to walk on. The trail then opened out into an old field full of young spring weeds and a scattering of the same invasive tree/shrub that we see regularly in Harrison Hills: privet. We followed the edge of the field toward the east and re-entered the woods on a broad, grass covered path.

About 50 yards down the path we heard and then saw a little warbler flitting around in the dense branches of the surrounding trees and shrubs. It took quite a while to get a clear look at him, but we identified him as a blue-winged warbler (Vermivora pinus)! Also, just before this warbler had flown into view, Deborah had spotted a plant that she had never seen before (its identity is to be determined!). We agreed that the extra walk on the Shoop Trail, mud and sloppy trail surfaces and all, had been more than worth it.

Then we realized that there were no trail blazes anywhere to be seen!

We backtracked to the spot where the incoming trail had opened out into the field and then carefully walked the edge of the field looking for more blazes to indicate the direction of the return loop. We could not find any.

Now, this is as “lost” as you can get in the Todd Nature Reserve. We knew which direction the cabin and foci of the trail grid was, but we just didn’t want to slog our way over the muddy sections of the Shoop Trail that we had already walked! We could see a road about a quarter of a mile to the west and assumed (correctly as it turned out) that it was the road that ran past the entrance to the Reserve. So we cut across the field, walked over a culvert that spanned the creek (which was high and running fast from all of the recent rains), and took the half mile or so walk back to the parking area.

There was very little adrenaline of rush in this “being lost” adventure, but we did get a nice extension on our walk around Todd!

Happy Spring (and almost Summer)!

 

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Signs of Spring #11: Field Sparrows and Bluebirds

Photo by D. Sillman

Photo by D. Sillman

Deborah and I were up at Harrison Hills Park two weeks ago hiking the route between our assigned bluebird boxes and keeping our eyes open for wildflowers and interesting birds. We parked near the cluster of purple martin houses (no martins yet!) just across from the Environmental Learning Center and were immediately greeted by a long, trilling, melodic song coming from the top of one of the many privet bushes/trees that are strewn across the meadow.

I had my larger (and heavier!) binoculars in the trunk of the car (I carry my smaller ones with me when I hike), so I got them out and zoomed in on the privet bush. Our singer was a male field sparrow (Spizella pusilla) (pictured above) singing so hard and loud that his little body shook with the effort!

The field sparrow is one that I never see around my house. They are a true “field” species that is intolerant of human activity and the structure (and hustle and bustle) of urban and suburban habitats. They are year-round residents of our area, but really show themselves off in the few weeks prior to mate selection and nest establishment.

Photo by D. Sillman

Photo by D. Sillman

In the winter, male and female field sparrows join multi-species flocks that included a mix of other sparrow species (including song sparrows and white throated sparrows). Field sparrows are much less aggressive than these other two types of sparrows and, so, probably spend much of their winter dominated by these more energetic birds. The field sparrow’s response to continually being displaced from overwintering food sources (primarily grass seeds) is frequently to return to sites following predator disturbance more rapidly than its flock mates. The increased risk of a lingering or returning predator is more than offset by a chance at a decent feed!

Male field sparrows break away from these winter flocks in early spring and return to their specific breeding sites with great reliability. In these sites, the males begin to sing to mark their territories and interact with each other to establish their breeding boundaries. Females arrive later, and they tend not to return to the territories of their birth nests or even to the territories in which they might have bred in the previous year. This more random selection of breeding sites by females (couple with the great specificity of site selection by males) very effectively reduces inbreeding within this species.

Females are frequently greeted by the male with physical contact and superficially aggressive behaviors (the male may fly at a female entering his territory and actually knock her to the ground! Maybe there is some pent energy from being so passive and submissive all winter?). Mate selection, though, quickly follows these altercations, and the female (with little help but often with much attention by the male) builds the nest.

Field sparrows can have more than one breeding cycle in a season, and their nest locations are quite different in the spring vs. the summer. In the spring the nests are usually built on the ground amid the growing grasses and weeds. Tree or shrub locations are still not adequately leafed out to provide cover or concealment. Later in the summer, though, the nests are built in the fully leafed out trees and shrubs where they are more protected against nest predators.

In the spring and summer field sparrows take advantage of a wide range of available foods in addition to their nearly continuous diet of seeds. Insects (including flies, bees, beetles, grasshoppers, and caterpillars) and spiders are protein and energy rich food sources consumed by the adult field sparrows and fed almost exclusively to their nestlings.

Field sparrow numbers have declined in recent years primarily due to habitat loss. They are a very welcome member of the Harrison Hills Park avian community, though.

Photo by D. Sillman

Photo by D. Sillman

This is our second year monitoring the twenty-eight bluebird boxes scattered across Harrison Hills Park. The original placement of the boxes was based more on convenience of access than on bluebird ecology, and one of last year’s goals of our “Cavity Nesting Team” (the name of our eight membered volunteer group) was to explore the possible variables that influence the selection of nesting boxes by bluebirds and also tree swallows (another important “cavity nester”).

We found that, in general, successful bluebird boxes were located about 30 to 40 feet from the edges of the woods (definitely not right on the edge of a field and definitely not in the center of a field). Most bluebird occupied boxes faced south (or southeast), and that bluebirds did not occupy boxes close to other bluebirds. Two bluebird boxes were very close to (within 100 feet) occupied swallow boxes, though. Bluebirds reproduce in staggered waves (three reproductive time events (April/May, May/June, July/August). Not a rigidly timed event). Survival to fledgling in our boxes was 66% overall. Early clutches had a higher survival to fledging (77%) than later clutches (50%).

Successful tree swallow boxes, on the other hand, were located further from the edges of the woods than the successful bluebird nests and were much more in the centers of the meadows. Two swallow nests were located near the Park’s big pond. Two swallow nests were located within 100 feet of active bluebird nests, and tree swallows reproduce in a more rigid time frame. Almost all nesting occurred in a May/June time frame (only one nesting cycle).  Survival of egg to fledgling was 71% in our boxes.

Last Fall the Cavity Nesting Team initiated a plan to put some of our observations and hypotheses into practice. We left all boxes that had tree swallow or bluebird nests in them where they were, and we moved the “no nest” boxes according to the following criteria:

  1. To the centers of the fields (to favor swallows)
  2. Near the ponds (to favor swallows)
  3. To 10 to 20m from the field edges, at least 100m apart, near mowed areas if possible, and put them out in pairs (to increase visibility and influence the birds’ perceptions of habitat quality)(to favor bluebirds)
  4. And we tried to orient all boxes to face the south or southeast

In October 201 we moved seven of the nine non-nested boxes into locations that corresponded to these hypothesized “more favorable” locations. We are now watching our boxes!

On our hike around two weeks ago Deborah and spotted our first bluebird eggs! We also opened one of our boxes and found a female bluebird protectively incubating (and maybe laying) eggs! Several of the other boxes have starts of nests, eggs and active bluebird “look outs,” too. Lots of bluebird action at Harrison Hills! I will keep you posted!

 

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Signs of Spring 10: Vernal Pools (and more!)

H. crucifer Photo by USGS (Public Domain)

H. crucifer Photo by USGS (Public Domain)

Spring frogs are important harbingers of the season in Western Pennsylvania, and Deborah and I listen for them carefully. The Spring Peepers (Hyla crucifer) are usually the first frogs to make their presence known. They begin their soft, peeping group choruses in and around small ponds and wetlands as soon as there are some warm, spring evenings. This year, however, we didn’t hear any peepers out in the usual places around our home.  This past winter’s lack of snow fall (leading to a low level of spring snow melt) and our very dry March and April may have cut into available water habitats for these little frogs to use as mating sites.

Gray tree frogs (Hyla versicolor) typically start their resonating trills soon after the peepers. This year we did hear some tree frogs out around our house in spite of absence of peepers, but their numbers and volumes were greatly reduced from previous years.  In some years the tree frogs continue to trill well into the summer. We’ll see if they can re-group or gather new strength.

There is a third frog that we regularly look for in this winter-to-spring transition: the wood frog (Rana sylvatica). We have to drive some distance, though, in order to see and hear wood frogs because they don’t do well in areas that have too many people.  They need dense, quiet woodlands with lots of leaves to hide under and lots of low spots for their spring mating pools!

Photo by D. Sillman

Photo by D. Sillman

So, Deborah and I drove down to Ohiopyle last weekend and met up with Rob and Michele for our annual, spring hike around Ferncliff Peninsula. We were looking for any new (or different) signs of spring, but in particular we wanted to see if we could find the wood frogs that were so abundant here three years ago (on a warm afternoon hike in late March 2013). The timing of the emergence of the wood frogs from hibernation and their frenetic mating in the temporary, spring (or “vernal”) pools of water (accompanied not by trilling or peeping but by a call that sounds like the quacking of a duck!) are all influenced by air temperatures and the abundance of surface water. Because of our very non-typical winter and spring, we were curious if there would be any amphibians at all! Also, incompletely filled pools might dry out before the aquatic larvae of the breeding amphibians have had sufficient time to develop legs and lungs. This disastrous outcome could wipe out an entire year’s crop of young amphibians.

Photo by D. Sillman

Photo by D. Sillman

We walked out onto the Ferncliff Peninsula at Ohiopyle. The day was getting warm, and it felt good when the sun finally came out from behind the clouds. The first part of the hike was over the far shore’s rocks and boulders along the Youghiogheny River at the Ohiopyle Falls. There was quite a bit of new flood debris along the shore, but Rob commented that the water level seemed lower than usual and the river rocks seemed more exposed and extensive than in previous years. Possibly in response to our near-drought more water is being held back behind the Youghiogheny Dam.

The isolated pools up and around the shoreline rocks, though, were full of life. Hundreds of tiny, black tadpoles were clustered together in the sunlit sections of the pool. Water striders were whirling and skimming across the still water and were actively bouncing into each other (establishing territories or mating?) and searching for food.  There were several types of eggs in the pool including the very distinctive cloudy and opaque eggs masses of the spotted salamander. Rob saw a small, brown salamander hiding in the brown leaves at the bottom of one of the pools. He poked it with the tip of his hiking stick (very gently!) and it swam to the back of the pool and buried itself in the leaves.

Photo by D. Sillman

Red Trillium Photo by D. Sillman

 

The trail climbed up away from the rocks and headed out along one side of the peninsula. The red maples and yellow poplars were all just starting to leaf out. They were covered with light green halos of tiny leaves. The abundant hemlocks and the scattered white pines made dark, bordering lines of green around the spindly hardwoods, and thick bunches of rhododendron bushes added their waxy deep greens to the landscape. The greens stood out sharply against the overwhelming brown ground cover of scattered, dead leaves. We also saw some spring wildflowers: red trillium, sessile leafed bellwort, and star chickweed (all pictured above and below).

 

Sessile leafed bellwort Photo by D. Sillman

Sessile leafed bellwort Photo by D. Sillman

Every time we hike this trail something happens to separate Deborah and Michele (who inevitably walk out ahead at a rapid pace) from Rob and I (who lumber along at our slow (but steady!) pace). When we made the big turn in the trail after inching along a narrow rock side trail that ran along a steep drop to the river, we got a glimpse of two people walking up and over a trail that ran up to the top of the peninsula. We thought that Michele and Deborah had taken the turn to go up, so we did too. Unfortunately we realized (after fifteen minutes or so of scrambling up the rocky trail) that the people we were following were not Michele and Deborah. We hope that they didn’t notice that we were stalking them!

We cut back down to the lower Ferncliff Trail, but by then were hopelessly separated from Deborah and Michele. Rob’s cell phone died in mid-text “where are…?” and so we plodded on following a couple and

Star chickweed Photo by D. Sillman

Star chickweed Photo by D. Sillman

their three little girls trying not to fall too far behind them!  Rob and I continued on the Ferncliff Trail and eventually re-made contact with Deborah and Michele near the trail’s end parking lot.

The Ferncliff Trail connects to the Great Allegheny Passage Trail. This is where we had seen the series of vernal pools full of wood frogs back in 2013. We checked them out very hopefully but were very disappointed by the water levels and quality. The pools were about half of their widths and depths of three years ago and were choked with algae and sediment and bits of litter and tossed debris. We saw neither frogs nor any egg masses nor any tadpoles. I don’t think that it will be a good year for amphibians in Western Pennsylvania!

Vernal pools are an important part of the forest habitats throughout the Eastern United States. They are small, shallow bodies of water with fluctuating water levels. Typically, these pools attain their maximum depths and volumes in the spring and their minimum depths and volumes in the summer. Many of these pools completely dry up especially in drought years or years of meager snow fall (like 2016!). A vernal pool must, according to Elizabeth Colburn in her excellent book Vernal Pools: Natural History and Conservation (2014), stay flooded for two or three continuous months, so it is, indeed, something more than just a rain puddle.

Vernal pools have no continuous inflows or outflows. They exist as isolated basins in the midst of their woodland ecosystems. This disconnection to streams and the possibility (or, more appropriately, the probability) of drying out generates a critical ecological feature of these pools: they do not have fish. And, this distinctive absence generates an aquatic habitat especially conducive to the development of a wide variety of amphibians whose eggs and immature life stages are heavily preyed upon by many fish species.

Vernal pools are greatly affected by the types and densities of the trees that surround them.  The chemical nature of the prevailing leaf species influences the acidity, turbidity and nutrient levels of the pool waters.  The history of a pool and the regularity and predictability of its occurrence and duration also has profound influences on the diversity and abundance of its breeding amphibians.

These pools in the Ohiopyle forests have been in place for many years and rely on sufficient melt and spring rain to fill them sufficiently. Let’s hope that next winter is a bit more snowy and that the March and April rains are more abundant. We need to hear ALL of the spring frogs next year!

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Signs of Spring 9: Red Maples (part 2)

Photo by D. Sillman

Photo by D. Sillman

I am looking out across a broad river valley here in Western Pennsylvania. At least one third of the trees I see are red maples (the photo to the left was taken about a month after the photo in last week’s blog). Last week I wrote about the amazing reproductive potential of the red maple and the readiness of its seeds to germinate and survive as seedlings in almost any natural and human generated habitat. Now let’s talk about the ultimate forest sculpting force in Pennsylvania today: the white-tailed deer.

Red maple seedlings are extensively browsed by deer in the winter. So, there is a large advantage for a seedling to grow as fast as possible in order to stretch itself above the browse level. Growth rates of red maples are prodigious: one foot height increases in the first year, two feet per year after that. Red maples, though, are also able to sprout after the above ground stem has been damaged. After a seedling has been browsed by a deer, for example, that individual can actually re-sprout at a growth rate of three feet per year! Sprouts, initially, have a faster growth rate than seedlings! There may actually be a selective advantage for a seedling to be browsed so that this accelerated growth spurt can be achieved!

Photo by D. Sillman

Photo by D. Sillman

The symbiosis between deer and red maples, then, is complex and, on the surface, seemingly contradictory. Deer eat red maples voraciously in the winter. But this winter browsing may actually stimulate those red maple individuals that are capable of the most robust sprouting response, to attain dominance in their ecosystem! Further, the sheer numbers of red maple seedlings in a forest floor community make it likely, especially in years of abundant browse, that at least some of the red maple seedlings will be passed over by the deer and, thus be able to survive to grow. Tree species that generate smaller numbers of seedlings are less likely to survive this intense survival filter of deer browsing.

Many insects feed on red maples, but few of these insects are serious, lethal pests. Gypsy moth larvae, for example, feed preferentially on oak leaves over red maple leaves possibly because of certain alkaloid chemicals that are present in the red maple leaf tissues. These alkaloids may also be an important in the red maple’s resistance against excessive summer leaf browsing by deer.

Public Domain

Public Domain

Red maples are extremely sensitive to fire. All of its life stages (seedling, sapling, “pole” tree, and mature tree) are easily damaged and killed by forest fires. Fire is a very effective way by which a forested ecosystem can be scoured clean of red maples! The minimal presence of red maples in pre-settlement forests and their predominant confinement to very wet habitats may be explained by the regular occurrence of fires in the drier habitats. Some of these fires, in fact, are thought to have been set by Native Americans in a management strategy that increased the dominance of oaks and sculpted the physical structure of the forest itself into a configuration more conducive to hunting and the support of deer populations. The wide-spread suppression of forest fires throughout the twentieth century may be an extremely significant factor in understanding the expanding distribution and abundance of red maples.

The pre-settlement forests of Pennsylvania were dominated by oaks (especially white oak), American chestnut, eastern hemlocks, and white pines. All of these tree species were extensively cut for timber, mine props, railroad ties, firewood, charcoal, tannins and other wood chemicals, and paper pulp. The oaks in the re-growing, secondary forests were then exposed to intense browse pressures by the re-surging white-tailed deer populations, and defoliated often fatally by the explosive outbreaks of the introduced gypsy moths. The suppression of forest fires also removed an on-going environmental factor that favored the dynamic persistence of the oak forest. The American chestnut was functionally exterminated as a potential canopy tree by the twentieth century expansion of the introduced fungus that caused chestnut blight. Eastern hemlocks were logged into near extinction in the state and, most significantly, the moist, highly shaded forest floor microhabitat in which their extremely specialized seeds and seedlings could germinate and grow was destroyed by the clear cutting and subsequent soil and litter erosion and drying exposure to direct sunlight. White pines thrived on sites with coarse, well drained soils and relied on periodic fires to reset their successional sequences and maintain a site consistency of white pines. Fire suppression, then, also limited the ability of white pines to reestablish their “pineries.”

Photo by D. Sillman

Photo by D. Sillman

The pre-settlement forests, then, were densely populated with highly specialized trees that had established and maintained themselves in their habitats. These tree species modified the characteristics of their habitats to favor their growth and survival. These species were also adapted to respond to the catastrophic but regularly occurring disturbance events that beset their ecosystems. Settlement, then, changed everything. The suppression of fire, the destruction of the ancient, persisting seed beds of the forest floor, and the introduction of exotic insects and diseases altered the stress and selection matrix of these forests possibly forever.  Tree species with broader tolerance ranges especially with regard to reproductive processes and stages were now favored. And, the red maple is acknowledged to be the “ultimate generalist.”

So, the question I have been pondering here in the shade of this wonderful red maple in the company of generation after generation of red maples, is “why are they here?” and “why are they everywhere I look?”

The destruction of the pre-settlement forest opened many niches. The failure of the hemlocks and white pines to reproduce, the loss of the American chestnut, and the on-going failure of the oak forest to re-establish itself reduced competition, and the incredibly fecund and adaptable red maple swept into the available ecological spaces.

Will other tree species succeed the red maple? Will northern red oaks, sugar maples, or American beeches (all slow growing but very shade tolerant species) become established in the understories of the red maples and eventually grow into the canopy? Or will the red maples maintain their dominance via their staggering numbers and ecological tenacity? Check back in hundred years or so to see!

 

 

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Signs of Spring 8: Red Maples (part 1)

Photo by D. Sillman

Photo by D. Sillman

There is a trail that Deborah and I have hiked many times over the years. We call it the “Up and Over,” and it runs up the north side ridge of the Kiski River and then down into the ravine of Roaring Run Creek. It is a very seldom walked trail although there are a few mountain biking paths that get some activity especially on nice, sunny weekend days. A great thing about hiking familiar trails is that you have a mental map of all of the nice spots where you can take short rests along the way. One of these places on the Up and Over is a sitting log under a large red maple way up on the crest of the Kiski Ridge. When you sit on the log (munching some favorite snack and having a cool drink from your water bottle) you look down over the Kiskiminetas River which runs fast and shallow over its red-brown, silt covered rocks and out across the tree covered framing hillsides and the distant ridges. Deborah’s picture above shows the scene from this spot in early April (next week I’ll show you what it looks like a month later!).

I remember sitting in this spot a couple of years ago in the third week of March before any of the trees had leafed out. It was a sunny day but damp and cold. There were even a few lingering patches of snow on the north-facing slopes and in some of the more shaded hollows.

Red Maple flower Public Domain

Red Maple flower Public Domain

About a third of the trees had a fuzzy, reddish glow around their sun-lit branches. These were the first flowering trees of the season and quite obviously from this high vantage point the single most abundant type of tree throughout this river valley. These gently glowing, red flowering trees were red maples.

The other common names of red maple describe important aspects of its ecology and uses. “Swamp maple” and “water maple” tell us that this species is a tree of wet soils. “Soft maple” indicates that the wood is easily worked (and maybe not as strong as the wood of some other types of trees), and “scarlet maple” is a name for those who maybe crave more elegant adjectives!    The presence of red maple all along the river and up the creek-cut hollows made sense relative to the tree’s ecological names, but the abundance of the tree along both the north-facing and south-facing ridges doesn’t seem to fit. Red maples were everywhere. Why?

Through the twentieth century, the red maple became one of the most widespread and abundant trees in eastern North America. In the pre-settlement forest, red maple was found in the places described by its many common names. It was a relatively minor tree of the overall forest and was concentrated in wet, poorly drained sites. How and why did this species proliferate so greatly? How and why did it spread over most of the available landscape?

Looking around from my sitting log I see red maples of all sizes and ages. Thousands of tiny seedlings fill up the spaces around the larger trees, hundreds of its thin saplings rise several feet up above them, and dozens of its skinny “pole” trees in turn rise up over them. This is a red maple forest in a robust state of reproduction. Again the question, “why red maple?”

One of the reasons that explain the “why and how” of red maples is the tree’s great ability to make seed. Flowering and seed production can begin in a red maple as young as four years of age. Young trees that are two to eight inches in diameter can make tens of thousands of seeds each year. Older trees that are a foot or more in diameter can make a million seeds in a single year. Bumper crops of seeds are produced every other year, but every year is a good seed year for red maples.

Photo by Dcrjsr, Wikimedia Commons

Photo by Dcrjsr, Wikimedia Commons

The seeds mature in double, winged samara and are shed from the parental tree in late spring. There are very few germination requirements for the red maple seeds. They can germinate in the shade under the parental tree, or in the direct sun many hundreds of yards away. They can germinate in very wet conditions or in very dry conditions. They can germinate on piles of leaf litter, on bare mineral soil, in cracks in sidewalks and driveways, in rain gutters, and even under the windshield wiper blades of a 1990 Geo Prism (personal observation). Ninety percent of the seeds produced can germinate and they are able to do so almost immediately after flying away from the parental tree.

The small seeds in their samaras can fly great distances in a strong wind. Any area with red maple trees will fill up with red maple seeds and seedlings, and this system saturation will be renewed each year! Most of the first year seedlings will not survive, but since there are so many of them each, and since each passing year adds countless more to the population, in a short period of time the forest understory will be full of red maples.

What is the nature of the competition and stress matrix affecting a red maple seedling?  First of all, there are the thousands of other red maple seedlings. For an individual seedling to prevail its genetic make-up and physiological potential must match up with the restrictions and factors of its environment.  Many studies have described the broad genetic range of red maple populations: different genetic types are found (and, therefore, have succeeded) in wet lowlands and in dry ridge ecosystems. Root growth patterns in these extreme sites are different (deep roots are favored in dry sites but shallow, spreading roots are favored in wet). Secondly, the seedling’s energy potentials must match the restrictions of its site. If it is in the deep shade of a closed canopy forest, the seedling must be able to live at low photosynthetic activity (and comparably low respiratory and growth activity) for many years. If the seedling is out in the full sun, it must be able to handle the large energy input of the full sun exposure and the potentially dry conditions that full sunlight exposure might generate.

(Next week: deer and red maples, a complex symbiosis!)

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Signs of Spring 7: Multiflora Rose

Photo by D. Sillman

Photo by D. Sillman

The color green is returning to our winter gray-brown ecosystems. The grass in our yards is starting to grow at an interestingly uneven rate. In my own yard places where Izzy has “visited” over the winter seem to be greening up faster and growing more robustly than the place not graced with her “presence (or should I say “presents?”). Lawns are looking shaggy all up and down my street, and they are getting more and more unkempt (or should I say more and more natural?) with each passing day. Some of my neighbors have been out mowing three or four times this season. The sound of their riding mowers roaring past my open windows with their distinctive Doppler whines makes me miss winter and its glorious quiet! Lawn grass that doesn’t look like carpet, for some people, is absolutely intolerable, but the energy and resources that our society pours into lawn care is obscene!

But don’t get me started on lawns!

Photo by D. Sillman

Photo by D. Sillman

The woods are greening, too, but much of this is actually not a welcome sign of spring. The first green in the understory of the forests around here is almost all due to the early leafing out of one particularly, noxious,  invasive plant: multiflora rose.

Multiflora rose (Rosa multiflora) is an introduced plant species that is native to Japan, Korea, and Eastern China. It was first brought to the United States in the 1860’s for use as root stock for ornamental roses. It was subsequently used as a “living fence” plant, as highway buffer vegetation, and in a variety of disturbed land reclamation programs. Soon, though, the invasive and destructive potential of this plant was recognized. Most states have placed multiflora rose on the “noxious weed” or “banned invasive” lists and are not only preventing its sale and planting and also actively attempting to extirpate it from areas in which has become established.

Multiflora rose can be found throughout the United States except for the Rocky Mountain region, the extreme desert southwest, and most of the state of Florida. It grows rapidly in fields, pastures, roadsides, and sun-lit edges and spaces of a forest. It is especially common in forest sun gaps that are generated by fallen trees. Its rapid growth and tendency to form dense, monocultural thickets allows it to out-compete and over-shade most native plants.

Photo by J. Mayer flickr

Photo by J. Mayer flickr

Multiflora rose is a perennial that grows in long (up to 15 feet), arching, thorny stems that are called “canes.” It has compound leaves that usually are divided into 7 to 9 serratedly edged leaflets. The leaves arise alternately on the long canes. Flowers (which form in May or June) are pink or white and very fragrant. They are pollinated by a diverse array of hymenopterans. A pollinated flower will eventually form a small, leathery, red fruit around a single, hard seed. This fruit is called a “hip,” and hips may persist on the

Photo by Vllseskoser flickr

Photo by Vllseskoser flickr

plant through the next winter and, possibly, for several years. Hips are consumed by a wide array of birds (including American robins, cedar waxwings, and northern cardinals). Passage of the seed through the digestive tract of a bird significantly increases the likelihood of the seed’s germination. Birds, then, represent significant ecological symbionts for the multiflora rose by accomplishing both seed dispersal and scarification.

In addition to developing from seed, multiflora rose is also capable of rooting from the tips of its arching canes. New canes grow up and over older canes, then, and form an expanding, dense mass of heavily thorned stems. These thickets allow very little other vegetative growth within them and, thus, represent an ecological disaster for native plant species. These thickets, though, do represent a highly protective microhabitat for many small mammals (like cottontail rabbits and woodchucks) and birds (including bobwhite quail, pheasants, and many small song birds).

Multiflora rose is one of the first plants to leaf out in the early spring. This early start on photosynthesis gives the plant an energetic advantage over its many potential competitors. The shade generated by the its leaves also acts to inhibit the growth and survival of many other spring plants. This is the time of year to look our across our wooded valleys or up and over our forested ridges to get an appreciation of just how much multiflora rose there is in our ecosystems! The early green we see is almost all this invasive plant species (along with some similarly invasive honeysuckles!), and it is shading and crowding out a huge number of our diverse, native plant species!

Photo by D. Sillman

Photo by D. Sillman

I have a large multiflora thicket at the bottom of my grassy field. I remember consciously avoiding mowing a spindly little rose cane that was growing out in the field about 25 years ago. I subsequently jogged my mower around the larger and larger and more and more highly branched rose bush, then rose patch, then rose thicket over the coming years. I don’t remember what I was thinking when I let that tiny plant live, but it is now a building sized, dome-shaped mass of heavily thorned, intertwined canes that serves as a roosting habitat for cardinals, a protective cover for a large woodchuck and a couple of rabbits, and black hole that has captured (and kept!) numerous soccer balls, Frisbees, and baseballs. It has also served as a seedling nursery for two mulberry trees that now stretched out over the thicket. These trees are covered with fruit in June and are a favorite feeding and gathering spot for flocks of American robins and cedar waxwings!

No other plants, though, grow under these rose canes. Carefully pushing the thorny canes aside all you see is bare soil without even a hint of the grasses and weeds that were there when the rose cane got started. The rose thicket is making some ecological contributions to my yard and field ecosystem, but it is also taking an awful lot of resources in return!

 

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Signs of Spring 6: What’s Living in Your Home?

Photo by CGP Grey, Wikimedia Commons

Photo by CGP Grey, Wikimedia Commons

Looking around the inside of your home is a very comfortable way to do some complex observations of nature. A house is a habitat not only for humans and their acknowledged cohabitating species (a wide range of mammal, reptile, bird, and fish pets) but also for many vertebrate and invertebrate species that find the non-stressful conditions of the inside of a house (not to mention the rich food sources and great nooks and crannies for reproduction and hibernation!) incredibly agreeable!

But, I don’t want to talk about the occasional raccoon that wanders into your garage or basement or the odd black snake that slithers in from the deck. We have all had birds and squirrels and bats in our attics, and I have even heard of deer pushing open screen doors and walking into living rooms and kitchens.

None of these species really “lived” in your house. They probably were frantic to get out once they realized that there were humans (probably screaming humans) way too close at hand!

Anyway, there was a research paper published in January in the journal PeerJ that looked at some more persistent fellow-occupants of our homes: the arthropods!

Mathew Bertone of North Carolina State University and his research team sampled for arthropods in fifty homes near Raleigh, North Carolina. They collected more than 10,000 specimens (on average 200 per house!) and found 34 taxonomic orders and 304 taxonomic families of arthropods. They very conservatively estimated the total number of species collected from the fifty houses at 579. On average each house sampled had 62 arthropods families and 93 species. A number of these species (149 to be exact) were quite rare and, as Bertone commented in an interview with The Atlantic magazine, “I encountered organisms I’ve never seen before as an entomologist collecting for 15 years in North Carolina.”

American cockroach, Photo by Sputniktilt, Wikimedia Commons

American cockroach, Photo by Sputniktilt, Wikimedia Commons

Most of these arthropods were not pest species. Cockroaches for example were only found in 6% of the houses, fleas were only found in 10%, and bed bugs (Cimex lectularius) were not found in any of the houses.

Species from twelve arthropod families were found in at least 80% of homes. These included “cobweb spiders” (family Theridiidae) that were found in 100% of the houses sampled , carpet beetles (family Dermestidae) also found in 100% of the houses, and gall midges (Cecidomyiidae) and ants (Formicidae) also found in 100% of the houses. There were also book lice (Liposcelididae) in 98% of the houses, dark-winged fungus gnats (Sciaridae) in 96% of the houses, “cellar” spiders (Pholcidae) in 84% of the houses, weevils (Curculionidae) in 82% of the houses, mosquitoes (Culicidae) in 82%, scuttle flies, (Phoridae) in 82%, leafhoppers (Cicadellidae), and non-biting midges (Chironomidae) in 80% of the houses. Dust mites (Dermatophagoides sp. (Pyroglyphidae)).were found in 76% of the homes sampled and significantly more mites were collected from houses that had carpeted surfaces than those that had hard surfaces (e.g., wood floors).

Common House Fly, Photo by USDA Wikimedia Commons

Common House Fly, Photo by USDA Wikimedia Commons

Four groups of arthropods dominate the average room sampled in this study: flies (23% of collected species), beetles (19%), spiders (16%) and hymenoptera (predominantly ants)(15%). Overall, there are more types of flies associated with human homes than any other group of animals. Book lice were the most ubiquitous indoor arthropod (found in 49 of 50 houses). Book lice are close relatives of the parasitic lice that have a long evolutionary history of living, among other places, in close association with birds, mammals and their nests (including those of primates).

Carpet beetle larva, Photo by A. Karwath Wikimedia Commons

Carpet beetle larva, Photo by A. Karwath Wikimedia Commons

Pest species that were collected, though, were quite typical of the same pest arthropods that have been detected in ancient archeological ruins! In other words, these species have been with us for a very long period of time! These pest species included grain weevils (Curculionidae), carpet beetles (Dermestidae), grain beetles (Silvanidae), cigarette and drugstore beetles (Anobiidae), house flies (Muscidae) and lesser house flies (Fanniidae)

Photo by D. Sillman

Photo by D. Sillman

This paper inspired me to do a visual arthropod scan of the rooms in my house. In the window frames of my workroom I found overwintering house flies, two very inactive earwigs, and several hibernating brown marmorated stink bugs. Up in the corners of several of the upstairs rooms I saw a number of small “cobweb” spiders and in the silk of their webs there were a number of small gnat-like flies well wrapped in spider silk awaiting their eventual ends. I have in the past found dust mites in the debris in the furnace ducts, but every other year cleaning of these ducts has greatly reduced this population (and my allergies, too!). Out on the glassed in porch I found overwintering lady bird beetles hiding under the aluminum

S. Williams, Flickr

S. Williams, Flickr

siding, and some more stink bugs under the carpet and in the drawers of a storage cabinet. In the basement I saw a fishing spider, several “cellar spiders,” and two “basement centipedes.” There were also a few drain flies in the basement bathroom and a few more hibernating stink bugs.

So, in a very casual, visual survey I found eleven different arthropods lurking in the corners and crevices of my house. I am far short of the 93 species average in the North Carolina study. If this were summer I know that I would add more flies (especially crane flies and several kinds of mosquito), some beetles, two or three kinds of ants, and probably a couple of kinds of moth or butterfly. Hopefully, there won’t be any fleas this year or ticks (but they almost always show up sometime in the summer!). We have, in fact, throughout the winter found the occasional deer tick on our dog. Dogs and cats are marvelous vehicles for the transport of arthropods into a house!

Finally, just to give you a little more perspective on the numbers of arthropods around us let’s look at some data from the Smithsonian Institution concerning insects (the most abundant and most diverse group of arthropods). According to the Smithsonian there are 10 quintillion (ten to the nineteenth power!!) individual insects alive on Earth at any given moment. That means for each of the 7.4 billion people on Earth there are 1.35 billion insects! Maybe we all need to add some extra rooms onto our houses to make space for all of our friends!

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Signs of Spring 5: Looking out the Window and Walking on Some Trails

Photo by D. Sillman

Photo by D. Sillman

Spring is starting to explode all around us. I have flocks of arriving blackbirds and grackles out under my bird feeders (usually in the afternoon). They chow down on the spilled seed and the leftover deer and squirrel corn and then head off on their way north (or east or west).It is nice to see them, but I hope that they don’t stick around too long. Their noise and aggressive behaviors drive the other birds away from the feeders.

Male cardinals (who have spent the winter very companionably feasting on black oil sunflower seeds together) now are chasing each other around the periphery of the yard. They square off, beak to beak with crests raised and heads slanting forward and low (such attitude!) in attempts to intimidate their opponents and get them to back off and leave the prime breeding spots (and females who are still busily eating their seeds!) to them.

The juncos are still here, so winter has not yet completely disappeared. The red maples are just starting to flower. They are flowering later than most previous years. The big silver maple at the bottom of my field has been in flower for a couple of weeks now. I am starting to feel the tree pollen in my itchy eyes and runny nose.

Photo by D. Sillman

Photo by D. Sillman

Robins have quickly become an expected species out in the field or in the back yard. Their status as harbinger of spring vanished very quickly! They are digging through my leaf piles looking for worms, and singing so beautifully at dusk and at dawn. When I take Izzy for her early morning walk, we are often chorused by a vibrant wall of bird songs. I hear robins, cardinals, titmice, and wrens. The crows and the blue jays add their own rhythms, too.

The scarlet and red oak pole trees all around the yard still have most of last year’s leaves attached to their branches. Passing winds rattle the dry leaves like castanets. Pretty soon the new, emerging leaves will weaken the attachment points of the old sending the old ones tumbling to the ground. Leaf fall as a sign of spring? Sure, why not?

Up at Harrison Hills Park I saw three downy woodpeckers fussing and chasing each other up and around a sugar maple tree. I assume that all three were males contesting the boundaries of their breeding territories. They also had spent the winter in much more social frames of minds and had been parts of the mixed bird flocks (along with chickadees, titmice, nuthatches and creepers) that foraged together for seeds and insect larvae. The female downies are probably still in one of these flocks, but the males have been compelled (ah, hormones!) to go off on their own.

Photo by D. Sillman

Photo by D. Sillman

The bluebirds are back at Harrison Hills, too! We saw two small groups of four male bluebirds also acting very badly toward each other. One of these groups was up around our boxes that line the periphery of the park’s northern meadow. Two the males were actually bouncing between two of our nesting boxes. One male perched on top of the box while the other ducked inside for a quick look around. Then they retired to a nearby tree to chatter and peck at each other. We saw one pair go beak-to-beak and actually crash to the ground in their argument! It was very tiring just watching them expend all of that energy! The female bluebirds will be arriving very soon. By then the males should have their territories all worked out and be ready to puff up, sing and be as impressive as possible!

We checked out the big pond at the south end of the park to see how the beaver is doing. We did not see any new beaver activity. The lodge in the middle of the pond looked unchanged from January. We did see a very handsome pair of mallards, though, swimming around the edges of the pond.

Photo by D. Sillman

Photo by D. Sillman

Walking across the fields at Harrison Hills we also saw colt’s foot flowers and swarms of little wolf spiders (Pardosa spp.) running about on the tops of the dead vegetation. Deborah did a beautiful ecological study of these spiders several years ago. In an old field ecosystem (much like this one up at Harrison Hills) she had found two, almost identical species of Pardosa apparently living together in a shared habitat. This would seem to violate one of those fundamental laws of ecology called the Competitive Exclusion Principle which simply states that no two species can occupy the same niche in the same ecosystem!   What Deborah did was then sample for the spiders first during the day and then during the night. She found that one species of Pardosa was active during daylight hours and the other was active at night! Niche separation! No violation of Competitive Exclusion and a very neat research project and paper!

Photo by D. Sillman

Photo by D. Sillman

Skunk cabbage is still in flower in most of wet areas of the park. It is just starting to send up its first green shoots and will soon fill in these low areas with its heavy, broad leaves.

Over Spring Break we flew out to New Mexico and enjoyed a jump start on the early to late spring transition. Flowers were blooming all over Albuquerque and trees (cottonwoods, willows, redbuds) were in early leaf (such beautiful light green shades!) or flower. The Sandhill cranes had departed just the week before we got there, but we saw flocks of robins (all in the city itself, none out in the surrounding desert), some really impressive raptors (Coopers hawks, Harriers, and kestrels). We even saw (while we were touring an animal rehab “zoo”) flocks of ravens (who perched on the tops of the cages of the captive birds (hawks, owls, caracaras, and, yes, even a raven) probably harassing them mercilessly (except at feeding time when the tables were turned!). We also saw a wild roadrunner scooting along the dirt path in between the cages of the peregrine falcons and the barn owl!

It was amazing walking on paths with a full sun beating down on our heads feeling a dry, wonderful 80 degrees! Our sinuses actually cleared out and I could feel my vitamin D levels returning to normal!

We are in typical March cycle of weather right now. One day is warm and sunny and the next is cloudy and cold. Rain and snow are in the long-term forecast. Summer is coming!

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Signs of Spring 4: Updates on Bats and Bees

USFWS, Wikimedia Commons

USFWS, Wikimedia Commons

My bat house came down this past December along with the wind broken spruce tree to which it was attached. I had put the bat house up back in 2010 in hopes of sheltering some little brown bats (Myotis lucifugus) and to try to help make a contribution in their recovery from the decimating impacts of white nose syndrome. No bats ever came to live in my bat house, though, and the house is now in my garage waiting to be repainted and, hopefully, reattached to some tree that will be noticed by some homeless little brown bats!

In summers past I would sit out on my deck in the early evening and watch a busy swarm of bats (mostly little browns) flying circles and crossing patterns in the fading light of the early night sky. Last summer, though, I would see, at most, one or two bats a night (each of whom was flying around my bat house tree with no recognition of its wonderful aspect (facing the rising morning sun) or its very high quality of construction!).

There was a report on the Penn State News website this past winter (December 4, 2015) that updated the bat population census from the Shaver Creek Environmental Center over near State College. In 2007 (the year coincidentally that the white nose fungus infection was first reported in hibernating North American bat colonies) 1400 little brown bats were in residence at Shaver Creek. Every night in the summer a crowd of observers gathered at dusk to watch clouds of bats emerge out into darkening night sky. This past year there were only 2 little brown bats at Shaver Creek. White nose syndrome and the immense winter die-off that it triggers was the cause of this staggering decline in these important animals.

Photo by A. Valentine, Flickr

Photo by A. Valentine, Flickr

A single bat will eat between three hundred to three thousand insects a night. A million bats, according to the Wisconsin Bat Monitoring Program, eat six hundred and ninety-four tons of insects a year! That’s a lot of mosquitoes and potential crop pests! It has been estimated that a farmer in our bat-deprived world will have to spend between four and five thousand dollars a year on pesticides just to achieve the insect pest control that the bats had provided for free.

Bats reproduce very slowly. A female can have only one pup per year, so the time frame for the recovery of the little brown bat population is going to be incredibly long, and this recovery will only occur if the winter die offs from the white nose fungus infections stops; a very big (and very uncertain) “if.”

There is a very recent piece of good news about bats and their response to the fungus that causes white nose syndrome. A paper published on March 9 in the Proceedings of the Royal Society B clearly demonstrated that Chinese bat species are resistant to these fungal infections, and the authors’ speculate that this resistance is genetic! If white nose syndrome’s spread can be slowed down, then, the hope is that Natural Selection for these similar genes in North American bat populations might result in fungal resistant bat populations here.

Last winter (January 23, 2015 “Signs of Winter 8”) I wrote about the winter survival strategies of a number of species of North American bees. For the sake of time and space several additional bee species missed the cut, so to speak, and their descriptions had to be edited out of the final essay. In order to start my bee discussion here on a positive note, I wanted to include a short description of a little known bee species that many keen bee observers find quite interesting: the mason bee.

Photo by B. Moisset, Wikimedia Commons

Photo by B. Moisset, Wikimedia Commons

Mason bees (Osmia spp.) are very short-lived (only six weeks or so), solitary bees. These bees nest in tubes or holes and have earned the name “mason” because of their tendency to build wall-like partitions made of mud inside of their tubular nests. A mason bee will gather pollen and nectar from the flowers that are blooming during its short life and primarily use its gatherings to pack food around the eggs that it lays in those mud-wall partitions of its nest. A mason bee may fill up more than one nest with its eggs and its accumulated nectar and pollen. The eggs then hatch into larvae, feed on the stored food and steadily grow and develop. The walls are extremely important here because they keep each larvae isolated with their own food supply! The mature larvae then spin a cocoon and develop into pupae which will, still inside the cocoon, then molt into adults. It is inside of this protective and insulating cocoon that the mason bee overwinters. In the spring, the male mason bees emerge first and wait outside of the nest for the later emerging females so that they can mate. After they mate, the males die, and the females then find suitable tubular structures for their nests and begin to lay eggs, gather nectar and pollen, and, as a great ecological tie-in to this activity, pollinate many different species of flowering plants.

So what else have we heard lately about bees?

In a report late this past summer (N. Y. Times, July 23, 2015) 70% of the honey and pollen samples collected from honeybees in Massachusetts contain neonicotinoid insecticide residues. As I reported in the “Signs of Fall 6” (October 1, 2015), a paper published in the April 25, 2015 issue of Nature showed that both honeybees and bumblebees were strongly attracted to flower nectars that contained neonicotinoid pesticides. These pesticides are commonly used for insect control on crops but have been linked to significant bee damage in many studies (The European Union has banned these pesticides because of their links to high levels of bee mortality. Bills have been proposed in the US Congress to restrict the use several of these pesticides, but these bills were sent to committee and no definitive action was taken). This unexpected affinity of bees to these chemicals may explain why they are so toxic to these important pollinators.

Argentine ant (Photo by Penarc, Wikimedia Commons

Argentine ant (Photo by Penarc, Wikimedia Commons

In a February 8, 2016 article in the N. Y. Times, it was reported that the Asian virus that causes wing deformities in infected honeybees was being spread not only from honeybee colony to honeybee colony but from continent to continent (Asia to Europe! Europe to North America! Europe to Australia!) primarily by the commercial trading and transporting of honeybee colonies! This virus has raced around the world in a very short time period and can, especially if combined with Varroa mite infestations cause colony collapse disorder. The Times also reported (in a September 11, 2015 article) that Argentine ants (Linepithema humile)(an invasive species ranked among the one hundred worst animal invaders in the world!) can spread these bee wing deforming viruses from honeybee colony to honeybee colony within their considerable invasive ranges (15 countries and 6 continents)! The introduction of a virus infected honeybee colony into an area also infested with Argentine ants seems to guarantee that the virus will be quickly spread to all honeybees in the area.

So, we have short-sighted pest control policies coupled with careless dispersion of infected and invasive species! It’s amazing we have any honeybees left at all!

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