GSWA participates in a wide variety of stewardship projects, both on our property the CMA, and elsewhere in the Passaic River watershed.
Invasive Species Removal
Invasive species are plants, insects, or animals that are not native to our region, and due to the lack of natural predators or disease, spread rapidly. Invasive species thrive in disturbed landscapes, and can quickly overtake habitat from native species, especially in New Jersey, where the overabundant deer population prefers to eat native plants. Because they did not evolve to be a part of our ecosystem, invasive species rarely provide any ecological benefit to native animals or plants.
When GSWA acquired the CMA, the property was overgrown with invasive plant species from other countries, including Multiflora Rose, Tartarian Honeysuckle, Japanese Stilt Grass, Garlic Mustard, Japanese Barberry, Privet, Burning Bush, Purple Loosestrife, and Russian Olive. These invasive species, which establish themselves when there is soil disturbance, thrived on the property, which was formerly used as agricultural land. The invasive plants, aided by excessive deer browse of native species, out-competed many woody native plants.
With the help of many hundreds of volunteer hours, GSWA has cleared a significant portion of those invasive species from the property, using best management practices to avoid their return.
The removal of invasives and the implementation of a deer exclosure have allowed the remaining native plants the chance to re-establish and thrive, reforming the various layers of forest that had been lost, and allowing the vegetation to intercept, capture, and store more water after rain events. Re-establishing native species has increased biodiversity at the site, as native berry producing shrubs and nectar plants slowly spread and recolonize.
Our ongoing stewardship work at the CMA includes replanting native plants that should be present as part of the plant communities on site. Often, replanting goes hand in hand with invasive species removal. Once an area is effectively cleared of invasive species and replanted with natives, the survival of the plants is tracked. Common native shrubs and trees are chosen that would normally thrive within these types of habitats, but have been out-competed by deer and invasive plants. These plants attract animals to the property, due to their role as a pollination, nectar, food, or habitat source, therefore increasing the biodiversity and ecological functioning of the habitats we manage. By replanting and protecting established native plants, the CMA will eventually serve as a source of native shrub berries and seeds that can spread back across the fencing, acting as a reservoir of native plants to the forests outside of the CMA!
Our replanting efforts have focused on selecting plants that have particularly valuable flower, berry, or seed producing characteristics to maximize their attractiveness and use by wildlife. In addition to bolstering food sources for particular species of wildlife, we have encouraged species to return and thrive by building or installing suitable nesting and overwintering habitats.
Bird boxes, bat boxes, and small mammal brush piles have all been created and installed to encourage wildlife use. Bird boxes are made to attract specific species, and are built according to the habitat and nesting preferences of those birds. Brush piles attract insects and small mammals such as mice and voles, which form an essential part of many food chains. These brush piles, created by piling branches to make dense clumps of woody material provide foraging places for winter birds, snakes, and other species.
Deer populations in the Morris County area have been estimated to exceed 100 deer per square mile in some locations, despite recent deer population crashes due to diseases like blue tongue virus. Ecologists typically believe that the natural carrying capacity of eastern forests (the number of deer a forest can support without ecological damage) is closer to 6-10 deer per square mile.
Large deer populations reduce biodiversity due to their selective grazing of native shrubs, seedling trees, and understory plants. Undergrowth gets trampled or eaten, which prevents plants from flowering and setting seed. Male deer damage trees by rubbing their antlers against bark, wearing it away and exposing the trees to pathogens. Deer hooves disturb the forest floor, creating micro-germination sites for invasive grasses to gain a toehold.
In order to curb the effect of deer and increase biodiversity at the CMA, GSWA constructed a deer exclosure in 2005 around 23 acres of the forested areas of the property. This area was expanded with additional fencing in 2009 to enclose 30 acres. The fence is approximately 7 feet high, with extensions to 8 feet in some areas where deer were able to jump the fence due to topography. Excluding deer improves the habitat for wildlife, especially for neo-tropical migratory birds, several threatened amphibian species, and invertebrate species. Additional small exclosures, acting as islands of native plants, are present in the unfenced sections of property. As a result of the fencing, we have observed an increase in native plant biodiversity, with more species of spring wildflowers and understory shrubs present. Permanent plant survey plots set up by Raritan Valley Community College are tracking the success in re-establishing diversity at the site.
Visitation and Education
A primary goal of the CMA is to educate visitors about the importance of land stewardship and highlight both the native and invasive species issues we face. The property has more than forty interpretive signs, which identify common plants and animals, showcase improvements that have been made to the CMA, and emphasize the importance of biodiversity and the protection of fragile habitats. Many of these interpretive signs have been created by local eagle scouts.
The CMA features nearly two thousand feet of boardwalk through the floodplain forest, several teaching areas, and seating for a class as well as individual benches allow hikers to rest and enjoy the sight and sounds of the property.
The CMA collects storm water runoff from I-287 and other nearby impervious surfaces. As the runoff enters the streams of the CMA, it causes bank erosion. GSWA has stabilized over 1400 feet of stream bank in order to reduce the effects of this runoff. Live stakes of native shrubs have been installed on streambanks, and have had positive results. The roots of these plants hold the dirt in place, reducing stream bank erosion and the amount of sediment that enters the water. Long term plans include instream restoration to increase the sinuosity of the stream channel – which has been straightened in the past – and plugging the drainage ditches that were installed when the land was used for agriculture, allowing for more effective flood storage at the site.
There are a number of vernal pools at the CMA. Stewardship efforts have involved replanting banks, removing sediment and debris that was causing pools to dry out too rapidly, and other enhancements to create better habitat for breeding amphibians. Frogs such as spring peepers, wood frogs, and chorus frogs, along with salamanders use the pools for mating and egg laying as an essential part of their life cycle. Vernal pools are critical for certain species, and are a very valuable characteristic of freshwater wetlands habitat. GSWA has girdled trees around several vernal pools and created boardwalk to facilitate access for programs.