The Forest
Biodiversity
The Black Rock Forest is located at the intersection of two large ecological systems: the New York – New Jersey Highlands and the Hudson River Basin. This location contributes to the high biological diversity of the Forest and the wide variety of terrestrial and aquatic habitats in the immediate vicinity.
The Hudson River itself is actually an arm of the sea with measurable salinity as far upriver as Black Rock Forest and Newburgh Bay, and with up-river and down-river tides alternating twice each day. Thus the River is also tremendously biologically diverse, with both freshwater and saltwater flora and fauna, along with the creatures that feast on them (including humans!). The Hudson is one of the great stories of ecological recovery as well, coming back from an extremely polluted state up until the 1960s to a point at which now more than 200 species of fish can be found in the river and its tributaries
Much of the biota of the River also live part of their lives in the numerous freshwater streams that feed the River, including those that drain from the Black Rock Forest. 
The majority of the Forest surface water drains north to Moodna Creek which enters the Hudson about 57 miles north of its mouth at the tip of Manhattan. Some southern portions of the Forest, however, drain into Highland Brook, which enters the Hudson at about mile 52, just south of West Point. Multiple interactions at all levels link the Hudson to the surrounding watershed areas. Among the most important of these links are the critical inputs of fresh water, chemical nutrients, energy, organisms, and sediment from streams to the River.
The very existence of the Hudson River as a sea-level cleft through the Highlands has resulted in a natural north-south passageway for many plants and animals (including, again, humans). For many species with distributions farther to the south, the Hudson serves as a sea-level corridor allowing dispersal farther north than elsewhere in their range.
Thus the immediate vicinity of the Black Rock Forest is remarkably variable in environment and biota: one can find blue crabs, bald eagles, bobcats, and boreal conifers all within a few miles of one another.
And, perhaps even more remarkable, all of this is also within sight of Manhattan (at least on a clear day)!
