Biodiversity and Natural History

Campus Ecosystems and Habitats

The Mount Holyoke campus encompasses a surprising diversity of ecosystems including: a stream, three reservoirs, over a dozen vernal pools, wetlands, forests (hardwood, conifer and mixed),  urban and open fields, all with high diversity of animal and plants. As part of an effort to inventory campus biodiversity, the MWCE has begun biodiversity surveys. The undeveloped part of campus is large enough to support populations of deer, several species of amphibians, and around 80 species of birds including Pileated Woodpecker and owls. Because of the size and location of this ecosystems, the campus properties can be viewed as an important conservation area in an otherwise developed landscape. In addition, the diversity of ecosystems and habitats on the MHC campus provides an opportunity to use the campus as a Living Lab (an outdoor environmental classroom).

Wetland Ecosystems

There are several types of wetlands found on campus including: forested swamps, scrub/shrub wetlands, wetlands with emergent vegetation, and vernal pools. Wetlands are areas of high productivity and high species diversity. 

Dams and Reservoirs

There are three dams across Stony Brook on the MHC property. Two of these dams created the two artificial lakes (reservoirs) on campus. The other dam is a spillway in front of the Willits-Hallowell Center.

Forest Ecosystems and Habitats

The 328 acres of property of the Mount Holyoke Trustees contains 278 acres of forests. Hemlock stands on campus provide valuable winter habitat for several species of wildlife, as well as nesting habitat for owls. Around 85% of our campus is forested. The remaining area is made up of fields, reservoirs, wetlands, streams, a golf course and the urban area. There are several different types of forest stands (70-90 years old) on the Mount Holyoke properties.

Stand Type Acres % of Forested
Oak and Hardwoods 78.4 28.2
Red Maple 94.5 34.0
White Pine/Mixed Hardwoods 45.4 16.3
Pine Plantations 42.6 15.2 
Abandoned Fields 17.5 6.3
Hemlock Stand *  *

The ground layer of forested wetlands is dominated by Cinnamon Fern (Osmunda cinnamomea) and other hydropyhtic plants as well as more evergreen cover which may increase the acidity of the soils. In many places, the understory has been invaded by exotic shrubs including Japanese Honeysuckle (Lonicera japonica) and Privet (Ligustrum vulgare). These invasive exotics tend to exclude native vegetation and often have a lower value to native wildlife. 

Eastern Hemlock Woolly Adelgid

A part of the Hemloc stand is destroyed by an exotic insect pest, the woolly adelgid. The insect has been detected on campus, and can kill a Hemlock in as little as 10 years after initial infection.


Pasture and Grassland ecosystems [PH]

MHC property includes the 28 acres of the Long Farm Tract. This area consists of a large 23 acre field and an adjacent 5 acre field. Long Farm is currently used as a hay field and jumping course for the Equestrian Center. The field is fertilized and mowed two to three times a year. This current management regime has a negative effect on the biodiversity of the site. Grasslands are among the rarest habitats in the Northeast. A combination of forest reversion from pasture and modern haying schedules have reduced the acreage and ecological quality of northeastern grasslands. Fields that were hayed once in the late summer are now fertilized and mowed up to three times a season. High nutrient inputs decreases plant diversity by favoring a few species that outcompete others. Butterflies, moths, and other insects that depend on specific host plants are also lost when plant diversity decreases. In addition, by mowing during the grassland bird breeding season, species such as Grasshopper Sparrows, Savannah Sparrow, Bobolinks and Meadowlarks lose their nests and the foraging area they need to raise their young. Restoring grasslands for biodiversity is a relatively easy task—change the mowing regime to mimic natural disturbances and in some cases seed the area with native grasses and forbs. Mowing can be done in the late summer after birds have bred. 

This is a view of a small section of Long Farm near the barn. This area is mowed less frequently then the rest of the tract and has a higher diversity of plants. It is an indication of how the rest of the area may look if less intensive management practices are adopted.

Reservoirs (Lakes) [PH]

The two lakes on campus are Upper and Lower Lake. Both bodies of water are dammed reservoirs. They are characterized as shallow lakes with short retention times (water passes quickly from inlet to outlet). Both lakes are also high in nutrients - eutrophic to hypertrophic. Nutrient loading occurs via inputs from Stony Brook and migrant and non-migrant waterfowl (Canada Geese and Mallard Ducks). The Golf Course and Equestrian Center may also provide nutrient inputs. Currently, the Golf Course withdraws water from Upper Lake. It has been determined that withdrawals from Stony Brook when the flowrate is low could result in further eutrophication of the lake.

Streams and Stony Brook [PH]

The heart of the MHC campus lies in the Stony Brook watershed. Stony Brook is the largest stream on the MHC property. Several smaller, intermittent streams feed into Stony Brook or reservoirs. The biological character of this stream is determined both by its geomorphology (shape, gradient, stream bed characteristics) and human influences. These influences include impacts from the surrounding watershed (agricultural runoff, construction and industrial effluents) and from within campus (runoff, alteration of the stream channel, and alteration of the vegetation adjacent to the stream). The water course of a stream can be divided into three broad categories of habitat based on stream velocity and depth—runs, riffles, and pools. Runs - deep moderately fast reaches. Riffles- high gradient sections with high turbulence. Pools - calm sections where sediments tend to collect. Each type of habitat provides homes for different types of stream organisms. Deeper calmer pools may support emergent and floating aquatic vegetation.

Sections of the riparian corridor on either side of the stream have been severely modified by human activity. A riparian buffer zone provides cover for wildlife, stabilizes the bank, and can filter runoff before it reaches the stream. If the buffer is too narrow, it cannot effectively provide these functions.

Vernal Pools [PH]

The Mount Holyoke College properties have at least a dozen vernal pools. Four of these pools have the definitive characteristics of vernal pools and have the organisms commonly found in vernal pools.

If you've seen a small pond in the middle of a forest or edge of a field that dries up during the summer, you may have been looking at a vernal pool. Vernal pools are a critical wetland resource for many species of animals and plants. Animals that require vernal pools for part of their life, usually breeding, are referred to as obligate vernal pool species. Obligate species include several varieties of salamanders, frogs and the fairy shrimp. These obligate species require bodies of water that are free from predators and remain wet for at least two months during the spring. Vernal pools typically dry up sometime during the summer or every few summers. This keeps fish—the obligate’s natural predator—from establishing permanent populations.

Obligate vernal pool species observed on MHC Campus

  • Wood Frog Rana Sylvatica 

Facultative vernal pool species observed on MHC Campus

  • Green Frog Rana clamitans
  • American Toad Bufo americanus
  • Spring Peeper Pseudacris crucifer
  • Painted Turtle Chrysemys picta

Breeding Amphibians and Vernal Pools

One way of finding a vernal pool is to use your ears. During the early spring, many species of frogs will travel to vernal pools to breed. Males attract females to the pools with loud and conspicuous calls. The first frogs to arrive at vernal pools are Wood Frogs (call sounds like a quaking duck), which are usually followed by Spring Peepers (call sounds like a high long trill). The sound of these choruses can sometimes be heard from a great distance. When the females arrive at the pools, they will pick a mate. The male clasps the female on her back and he releases sperm while she releases her eggs. Some species release their eggs in conspicuous egg masses. These masses have a gelatinous appearance with a central dark spot. Other species lay their eggs in smaller clusters or singly. The eggs develop into tadpoles, and until they metamorphose into frogs, they spend their time feeding in the vernal pools. Once tadpoles develop feet and absorb their tails, they leave the ponds for the uplands surrounding the pool. Some years, the pond dries up before they finish this process, and the population’s breeding attempt for that year ends in failure. Small, shallow pools are more likely to dry up before the frogs emerge than larger, deeper pools.

A salamander's use of vernal pools is a less conspicuous and lengthy affair. During the first warm rain in March, salamanders will move down from the uplands into vernal pools. There they will perform courtship displays. When a pair finds each other suitable, the male will deposit a spermatophore on the pond bottom. The female then walks over the spermatophore and takes it into her genital opening. She then uses the sperm contained in the spermatophore to fertilize her eggs. Depending on which species, she will either lay her eggs in egg masses attached to sticks, or deposit her eggs in small groups or individually. The eggs hatch and the salamander larvae spend several weeks feeding and developing into a juvenile salamander. The young salamanders then leave the pool for the surrounding upland environment.

Suburban and Parkland Habitat [PH]


Potential Impacts

  1. Habitat fragmentation—barrier to animal movement
  2. Storm Water runoff—oil, gas and road salt runoff from roads and parking lot in Stony Brook and campus ponds

The Middle Connecticut & Stony Brook Watershed [PH]

A watershed is a geographic area in which all surface and ground waters flow through a common drainage—commonly a series of streams, rivers, ponds and lakes. The Connecticut River drains a watershed that crosses three state boundaries. Many smaller watersheds, or sub-basins, flow into the Connecticut River watershed. For more information about watersheds, visit the following links and read below.


This is a map of the Middle Connecticut watershed and some of the smaller rivers and streams that empty into the Connecticut River. Areas marked in purple do not meet the water quality standards of the Clean Water Act.

Location of Middle Connecticut Watershed

The Pioneer Valley is in the southern part of the Middle Connecticut watershed. The Connecticut River watershed has been divided into three sections: upper, middle, and lower. This was done to ease regulation and management of New England's largest watershed.

The Pioneer Valley, which includes Stony Brook, is within the Middle Connecticut watershed. The Stony Brook and Bachelor Brook watersheds are the two major drainages in the area surrounding Mount Holyoke College.

South Hadley Watershed [PH]

Streams in South Hadley

  1. Dry Brook
  2. Bachelor Brook
  3. Stony Brook
  4. Buttery Brook
  5. White Brook
  6. Connecticut River

Ponds in South Hadley

  1. Pearl City
  2. Quenneville
  3. Aldrich
  4. Forge
  5. Stony Brook
  6. Leaping Well Reservoir
  7. Upper & Lower

Stony Brook Watershed Land Use [PH]

Mount Holyoke College is located in the Stony Brook watershed. The water quality of a watershed is in large part determined by the types and extent of land uses within the drainage.

Land use in the Stony Brook watershed is dominated by human activity (53.7%).

Stony Brook Watershed Land Use 1985

Depending on land cover, the impacts on water quality may be influenced by different factors.

• Agriculture - fertilizer, manure, and soil runoff
• Human - stormwater runoff, sewage, lawn chemical, and industrial effluents
• Vegetation - type of vegetation may determine nature of runoff

Invertebrate Survey (PDF) [LB]

Survey of an important group of bioindicators of stream quality.

Fish [PH]

Fish found on the campus properties (Stony Brook, Upper lake and Lower Lake):  PDF, Excel [LB]

Name Scientific Name
American Eel Anguilla rostrata
Blacknose Dace Rhinichthys atratulus
Creek Chub Semotilus atromaculatus
Fallfish Semotilus corporalis
White Sucker Catostomus commersoni
Pumpkinseed Lepomis gibbosus
Tessellated Darter Etheostoma olmstedi
Brown Bullhead Catfish Ameiurus nebulosis
Chain Pickerel Esox niger
White Crappie Pomoxis annularis
Yellow Perch Perca flavescens
Largemouth Bass Micropterus salmoides
Smallmouth Bass Micropterus dolomieui
Yellow bullhead Ictalurus natalis
Black Bullhead I. Melas
Channel Catfish I. Punctatus
White perch Morone americana 
Bridled shiner Notropis bifrenatus
Sunfish spp. Ictalurus spp. (several species)

Birds, Reptiles & Amphibians, Mammals and Plants [PH] & [LB]Excel file

The Botanical Garden catalogs the plants in their greenhouses as well as trees, shrubs and plants on the landscaped parts of campus. They have developed a database and posted information about their collections on the Botanic Garden Web site.

Privet (Ligustrum vulgare)

A climbing vine that has paired, opposite leaves. The fruits turn black when ripe, and are dispersed by song and game birds.

European Honeysuckle (Lonicera zylosteum)

Opposite, elliptical leaves that are hairy underneath. Fruit is bright red and dispersed by birds.

Japanese Barberry (Beberis thunbergii)

Alternate, small leaves with thorny stems and red fruit. As with many invasive shrubs, seeds are dispersed by birds.

Other invasive species on campus include: Multiflora Rose (Rosa multiflora) and Burdock (Arctium minus).

Waterchestnut - A non-native aquatic plant [PH]

The Waterchestnut (Trapa natans) is an introduced floating aquatic plant that often forms dense mats on the surface of lakes and ponds. The mats block light to the water and can adversely affect other aquatic organisms. These mats tend to displace native aquatic vegetation that is more valuable to wildlife. In addition, the presence of Waterchestnut can prohibit recreational uses of water bodies such as swimming and boating.

The Waterchestnut (Trapa natans) is an introduced floating aquatic plant that often forms dense mats on the surface of lakes and ponds. The mats block light to the water and can adversely effect other aquatic organisms. These mats tend to displace native aquatic vegetation that is more valuable to wildlife. In addition, the presence of waterchestnut can prohibit recreational uses of water bodies such as swimming and boating.

Waterchestnut is identified by a rosette of diamond shaped leaves. Each leaf is serrated on the outer margins and smooth on the inner margins. The stalk of each leaf has an enlarged region which acts as an air bladder and keeps the plant afloat. Several rosettes are attached to a central root that is anchored in the mud.

The plant is able to grow from the main root. Therefore, the root must be removed to effectively eradicate this weed.

The seed of the plant is black, hard and has four sharp spines. Seed can float and provide a way for the plant to disperse to downstream waters.

Waterchestnut was first recognized as a problem on campus in the 1940's. During the last several decades, efforts have been made to eradicate this weed from Lower Lake. The primary control methodology has been mechanical raking of the lake using an aquatic weed harvester. The College has employed Aquatic Control Technologies, Inc. to annually harvest Waterchestnut on Lower Lake. This method is useful when the Waterchestnut population has already exploded. However, unless the remaining Waterchestnut is removed by hand, the plant will quickly reestablish itself. (Photo courtesy of MHC Archives)

Waterchesnut has recently invaded Upper Lake. Found in ponds and lakes upstream from Upper Lake, the plant probably colonized the lake by seeds washed down Stony Brook.

In an effort to prevent Waterchestnut from establishing itself on Upper Lake and enhance the eradication efforts on Lower Lake, students and CE staff spent two afternoons on the Lakes removing the weed by hand.

The MHC volunteers (students, faculty and staff) biannually organize a teams to remove Waterchestnut from the campus lakes. This effort could help eradicate the weed from campus and potentially save the college thousands of dollars.

Since Waterchestnut may invade campus from upstream, we will have to remain vigilant to prevent reestablishment.


Page created and maintained by Leszek Bledzki
Peter Houlihan – text and pictures marked [PH]
Leszek A. Bledzki – text and pictures marked [LB]