Thawed Frogs at Ravenswood Park

Ravenswood Park, Gloucester, MA


Last Sunday was absolutely gorgeous–the perfect day to check out a local conservation area that we’d never visited before. Not wanting to choose between a trip to the forest and a trip to the shore, we decided on the best of both, and drove up to the North Shore to visit Ravenswood Park, a 600 acre area maintained by the Trustees of Reservations. The Trustees are a member-supported non-profit group that preserves over 100 areas throughout Massachusetts for the benefit of the public. Ravenswood park offers 10 miles of paths and carriage trails for hiking, birdwatching and cross country skiing.


Ravenswood-Park-Trail-Map


We were excited to learn that Ravenswood is home to some unique ecosystems featuring communities of eastern hemlock (Tsuga canadensis) and sweetbay magnolia (Magnolia virginiana), as well as a number of actively breeding amphibians. Before we set out, a staff member in the visitor center provided helpful information about spring happenings in the park. She also informed us about the conservation efforts at Ravenswood to protect the magnolia stands from ravenous deer populations. We decided on taking the Magnolia Swamp Trail to the Fernwood Lake Trail, and finally the Ledge Hill Trail, to see the best of what the park has to offer.


Adelges tsugae (Hemlock woolly adelgid) on hemlock foliage


We had barely begin hiking and already great stands of mature hemlock rose up from the sides of the trail. Hemlock is a majestic, historically important species in the northeast. Unfortunately, it is under the widespread attack of the hemlock woolly adelgid (Adelges tsugae) as seen in the image above. These scale-like insects came to the US in the 1950s from Japan, and quickly spread through eastern hemlock populations, attacking trees of all ages. By 2016, it is estimated that over 90 percent of eastern hemlocks have been effected (read that twice!). The demise of hemlocks will have profound impacts on carbon cycling in the northeast, where vulnerable trees make up a great deal of forest biomass (in Vermont, hemlock is the 3rd most common tree). The spread of this voracious pest is truly a tragedy, and serves as a reminder of the rapid impacts of globalization on species that have colonized regions over thousands or millions of years.

We found wolly adelgid throughout the entire Ravenswood hemlock population. It has already taken a great toll on the ecosystem of the park. Unfortunately, it wasn’t the only pathogen that has had a widespread negative impact on the area.


Beech bark disease canker on Fagus grandifolia (American Beech), Neonectria faginata, Neonectria ditissima


In addition to hemlocks, Ravenswood has an impressive population of another one of my favorite trees–the American beech (Fagus grandifolia). Many areas of the park consist entirely of beech and hemlock stands. Unfortunately, as seen in the image above, a great number of beeches here are colonized by pathogenic fungi. Beech bark disease is the result of a scale insect burrowing into bark and creating a wound that will then become home to Neonectria faginata and Neonectria ditissima. The spread of these fungi will eventually weaken and kill the tree. Many of the beeches at Ravenswood seem to be infected with beech bark disease, and the damage is already apparent throughout the park. Beeches, along with hemlock, are another majestic forest species that face a dire threat. The rapid spread of these pathogens will likely transform the forests of the northeast in the coming decades.


Downed White Pine (Pinus strobus)


A great many trees at Ravenswood have become victim to pathogens and have recently fallen. This eastern white pine (Pinus strobus) came down very recently, and happened to land in the crotch of a nearby beech.

Because of the great turnover of infected trees in the park, there is an amazing proliferation of organisms that obtain their carbon from decaying matter. Below is a gallery of some of the various fungi and lichen that we found during our hike.



The sheer amount of decaying biomass at ravenswood provides an excellent habitat for many species of fungi, although only a few are represented here. We’re excited to return in the fall to see what others we might find.


Ravenswood Park, Gloucester, MA Polypodium virginianum (Rock Cap Fern) on granite boulders Polypodium virginianum (Rock Cap Fern) on granite boulder Polypodium virginianum (Rock Cap Fern)


The Magnolia Swamp Trail provides an incredible walk through a primordial-looking forest full of vernal pools and granite outcroppings. An abundance of rock cap fern (Polypodium virginianum), an evergreen, gives the landscape a prehistoric feel.


Dicranum scoparium (Broom Moss) with fruiting bodies


The fruiting bodies of this broom moss (Dicranum scoparium) were catching the sunlight perfectly.


Kalmia latifolia (Mountain-laurel) buds and foliage with fungal spots


While the magnolias in the park are currently fenced off from deer, and thus inaccessible, the twisted, gnarled trunks of mountain-laurel (Kalmia latifolia) are a wonder to see, giving the impression of great age. Their flowers are remarkable–definitely worth a revisit later in spring.


Kalmia latifolia (Mountain-laurel) with abnormal branch growth


One mountain-laurel had a eerie-looking protrusion of abnormal growth that I’d never seen. I pulled apart the dense mass of twigs but couldn’t find the source of the abnormality. It’s possible that this type of growth was caused by a natural mutation, or by a parasitic insect altering the genetics of the plant, in the same way a gall is formed.


Hamamelis virginiana (American Witch-hazel) spent flowers


The spent flowers of witch-hazel (Hamamelis virginiana) are hard to miss. This winter seems to have been a good one for member of Hamamelidaceae.


Viburnum lantanoides (Hobblebush) dormant winter bud Clethra alnifolia (Summersweet) seed head


Other swamp plants flourish near the trail. The amazing winged buds of the hobblebush (Viburnum lantanoides) will open soon to reveal a gorgeous flower and large leaves. The seedpod of summersweet (Clethra alnifolia) is all that remains of last year’s fragrant blooms.


Ravenswood Park, Gloucester, MA Ravenswood Park, Gloucester, MA Ravenswood Park, Gloucester, MA


On the Fern Lake Train, the landscape becomes dryer and more rugged at a slightly higher elevation. A proliferation of white pine saplings gives some clues as to what these forests will look like in the coming decades, as new species succeed those killed of by disease.


Beech Stand (Fagus grandifolia) Fagus grandifolia (American Beech) breaking bud


A stand of young beeches already shows signs of weeping cankers and colonization by lichen. Below, a golden terminal beech bud begins to break, its bud scale peeling back. Soon, the green tips of juvenile leaves will emerge.


Acer pensylvanicum (Striped Maple) dormant buds Acer pensylvanicum (Striped Maple) juvenile bark


Occasionally we found the distinctively colorful bark and buds of striped maple (Acer pensylvanicum). This was the thickest trunk I could find, and I wonder about the origins of this relatively young population.



The decaying hemlock trunks provide energy for a great number of organisms, including whatever created these galleries–most likely carpenter ants or termites.


downy woodpecker (Dryobates pubescens) feathers Fur


We also found evidence of wildlife. A burst of downy woodpecker (Dryobates pubescens) feathers suggests some kind of struggle; below, the fur of a unknown forest inhabitant, perhaps the culprit in the altercation.


Quarried granite


A number of quarried boulders on the Ledge Hill Trail suggest our proximity to the park’s granite quarry. In addition to the quarry, there are Native American hunting mounds throughout the area. We also passed many cellar foundations and stone walls built by early Cape Ann settlers.


DSC_9803


I present this without comment.


Ravenswood Quarry, Gloucester, MA


The quarry itself has fallen into disuse and now serves as a scenic habitat for breeding amphibians.


Eastern Point Lighthouse


Just past the quarry, a high granite outcropping gives way to a view of the ocean. In the distance, we could barely see the Eastern Point Lighthouse.



Finally, we reached a large vernal pool, where our staff member told us we could find frogs, shrimp and salamanders in abundance, during this crucial mating season. We saw many salamanders drifting among the leaves. We couldn’t find any wood frogs (Rana sylvatica), but we could certainly hear them!


 


 

The cacophony in the video above is the sound of the wood frog mating frenzy. This incredible species is able to overwinter beneath moist leaf litter on the forest floor. By concentrating solutes like urea throughout their tissues, the frogs are able to prevent the damage caused by ice crystals. They can withstand multiple freezing/thawing events, and are among the first animals to emerge from hibernation in early spring as the last snow melts and sunlight warms the forest floor.

After thawing, the frogs begin a mad dash to the nearest vernal pools, temporary bodies of meltwater and rainwater that serve as breeding grounds for many species. Male frogs grab females aggressively from behind, latching their thumbs together in a position called amplexus. It is not uncommon to see a female with multiple males clinging to different parts of her body. The female deposits her eggs, and they are fertilized by the male. Many females may deposit their eggs in a single mass, with the inner-most clutch developing the fastest in the warm, protected environment. The development of offspring must outpace the drying heat of summer, so a considerable advantage is conferred upon those who can mate the quickest and who produce eggs that develop most rapidly. The breeding ritual of the wood frog is truly a race against the seasonal clock.

Many species are wholly dependent on these vernal pools, which provide substantial protection from the larger predators of ponds and lakes. When the viability of these pools is threatened, either by land development or climate change, these species become threatened as well. Luckily, Ravenswood is full of protected vernal pools, where guests can find these important New England species in abundance. The discovery of our noisy wood frogs was the perfect ending to a glorious spring day.

Thanks for reading,

Danny

 

 

 

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One thought on “Thawed Frogs at Ravenswood Park

  1. Pingback: The Hemlock Woolly Adelgid Documentary | [Amateur Ecologist]

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