This information has been extracted from the New Jersey Pinelands Comprehensive Management Plan.

EVOLUTION OF THE PINELANDS ECOSYSTEM

The present Pinelands landscape and ecosystem have been shaped by natural processes which began millions of years ago and, more recently, by the influences of man. A knowledge of these events is necessary to fully appreciate the region's significance and to plan for its continuing maintenance.

Three factors contribute to the essential character of the Pinelands. First are the physical features of the landscape that distinguish the natural habitats of the region . These include relief, soils, and hydrology. Second are living organisms, the plants and animals that characterize the Pinelands. And third are ecosystem processes, the dynamic interrelationships among and between the living organisms and their particular habitat elements. Such interrelationships have evolved through thousands of years, giving us the Pinelands as they exist today. Outside influences, natural and human-cause, may interrupt or modify these interrelationships and change the essential character of the landscape.

Only general knowledge is available of the particular geologic events and climatic changes that caused the formation of the Pinelands area and of the times at which these occurred. The history of the origin and development of the present plant and animal populations cannot be fully documented, nor is there complete agreement on or understanding of man's influence on the Pinelands. Nevertheless, scientists have uncovered enough evidence to make it possible to draw reasonable assumptions about the evolutionary history of the Pinelands and the significant influences on this history.

The following discussion identifies the significant natural and man-made influences that are believed to have made the Pinelands landscape and ecosystem what they are today. These are presented chronologically in four groups to give a sense of the evolution of the region. The four time periods are the epoch prior to the Pleistocene Ice Age, the Pleistocene Ice Age (1.8 million to 10,000 years ago), the period from 10,000 years ago to the time of European colonization, and the period from European colonization to the present.

Early Geologic Processes

The processes of deposition, sea level change, erosion, and land uplift are responsible for the present topographic and hydrologic features of the Pinelands. The present mineral soils have developed from the geologic parent material. Topography, hydrology, and soils, as well as climate, have a controlling influence on plant and animal populations. Geologic processes in the past have thus had a significant influence on today's Pinelands landscape and ecosystem.

The Pleistocene Ice Age is assumed to have started about 1.8 million years ago. Two earlier phases were particularly important. The first was a sequence of marine deposition and erosion which started
about 100 million years ago. The sea covered the land, leaving sedimentary deposits composed mostly of clays, silts, sands, and gravels. When the sea withdrew, erosion proceeded, and streams and wind carried away some or all of the sediments. The deposition and erosion sequence occurred many times in southern New Jersey, resulting in deposits over the basement rock ranging from a veneer covering to layers 1,300 to 6,000 feet thick. These deposits form the Coastal Plain in which the Pinelands are located. Names have been given to distinctive and mappable units of these clays, silts, sands, and gravels. In the area of the Atlantic Coastal Plain now designated as the Pinelands, the last marine deposit of this period has been named the Cohansey Sand. The Cohansey overlies an older deposit, called the Kirkwood Formation. Both are important in the later processes in which the surface of the Pinelands evolved.

The second important early geologic period began about 5 million years ago, when the sea withdrew from southern New Jersey and the land uplifted. The most recent sedimentary deposits were left exposed at the surface. In the Pinelands area, this was primarily the Cohansey Sand, which now undergirds almost all of the present Pinelands. The older Kirkwood Formation is exposed at the surface along the northern and western borders of the Pinelands. The Cohansey Sand is composed mostly of uncemented yellow quartz sand with variable amounts of fine to coarse, silty, and clayey sand. The Kirkwood Formation is also unconsolidated and is composed mostly of sand, silt, clay, and a little gravel.

Following the exposure of the Cohansey Sand, patches of gravels, sands, silts, and clay were deposited in localized areas on the Coastal Plain. These formations are identified as the Beacon Hill, Bridgeton, Pennsauken, and Cape May. The first three deposits are assumed to be pre-Pleistocene. The Beacon Hill Gravel is important from a landscape point of view. Today, it caps many of the highest hills in the Pinelands. The original sands surrounding the gravel were eroded away, leaving the gravel as a hill. This unusual geologic feature is known as "inversion of topography" because the younger, gravelly streambed deposits form hilltops.

The predominance of sand as the surface material had a major influence on the ultimate development of the Pinelands. The region's low relief is related to the nature of the Cohansey and underlying formations. The sandy composition of the Cohansey and the Kirkwood are responsible for the unique character of the surface and groundwater systems.

Variations in soils depend on the nature of the parent material and the influence of factors such as climate. Soils differ in their water-holding capacities, in their acidity, and in the type and amount of plant-supporting minerals they contain. Each plant species exhibits a certain range of need and tolerance for water and particular nutrients, as well as for other factors such as soil acidity. A plant species that grows and reproduces successfully on one soil type may not be able to exist under different conditions. The soils that developed over time from the Cohansey Sand and patches of subsequent deposits are low in moisture retention, low in nutrients, and high in acidity. These characteristics, interacting with other factors, have had a great influence on the types of plant and animal communities which have developed in the Pinelands.

The Pleistocene Ice Age

An epoch of glaciation known as the Pleistocene started about 1.8 million years ago and ended about 10,000 years ago. During that time, at least three of the four major ice advances reached New Jersey. The last one was known as the Wisconsin. It came the fastest south, but stopped 10 to 40 miles north the Pinelands area. Between the successive advances, extended intervals of warmer climate occurred. During these intervals, the glacial ice melted and the glacier retreated. The climatic changes and advances and retreats of the glacier affected sea level because of the varying amount of water tied up in the ice. When glaciation was at its maximum, sea level was at its lowest, and the North American Atlantic coastline extended many miles east of its present boundary. As the climate became warmer and glacial ice melted, and land areas previously covered by vegetation were inundated by sea water. These events of the Pleistocene epoch had major impacts on the Pinelands.

It is assumed that plants and animals colonized the Coastal Plain in the long periods prior to the Pleistocene, when the sea did not cover the land. The evidence of the types of species which were present then is limited. Some scientists interpret the available information as indicating that a few plants which are related to species present today in the Pinelands may have existed in these ancient times. Slightly more evidence is available on the plant and animal communities of the later Pleistocene time and on the influence that climatic and sea level changes had on them.

It is believed that in the late Pleistocene, when the Wisconsin ice was present north of the Pinelands, the climate in the region was considered cooler, and probably wetter, than at present. Many scientists believe that at this time the Pinelands area was covered by a forest similar to that which is now present in northern New England and Canada (a spruce-fir boreal forest). Some believe that the climate was so cold that the Arctic type of tundra vegetation existed here. In either case, the assumption is that the Pinelands plant and animal populations as we know them today developed only after the Wisconsin ice began to retreat about 10,000 years ago.

When the glacier started its final retreat from New Jersey, the sea level was still far to the east of the present North American Atlantic coastline. This increased the coastal migratory path for both southern and northern species, a factor which significantly influenced the composition of the modern Pinelands flora and fauna.

From 10,000 Years Ago to the Time of European Colonization

Although the topography, soils, and hydrological features of the Pinelands stem from the geologic processes that took place over millions of years, the plant and animal populations which exist today developed in the last 10,000 years. The two most important influences on this slowly evolving development have been climatic changes, and the interactions of natural biological succession and evolutionary adaptation processes with the physical components of the Pinelands environment.

Because every type of plant and animal has environmental tolerance limits and an optimum range for maximum growth the reproduction, climatic as well as other environmental factors have controlling influences on species distributions. While a species may flourish under the climatic and soil condition in one geographic region, or one site within a region, it may be unable to reproduce successfully or even to exist in another region or site having a single environmental condition outside its tolerance limits. As climatic conditions change, so will the geographic ranges of living organisms. Warming trends result in northward migration of southern species and cooling brings the more northern species southward.

It is believed that climatic changes in the last 10,000 years caused northward and southward dispersals of plant and animal populations, and that these are reflected in present Pinelands populations. About 5,000 years ago, the cool moist period which existed when the glacial ice started to retreat was followed by a warmer period that lasted several thousand years before the climate again turned colder. Enhanced by the enlarged coastal migratory route, plants and animals of more southern regions migrated northward. Some of these species colonized the Pinelands. It is believed that the Atlantic white cedar, a relative newcomer to the Pinelands, colonized the region during this period. To a lesser degree, migration also proceeded northward and then east to the Pinelands from the southern Appalachian area. During this same period the characteristic tree of the Pinelands, the pitch pine, may have migrated as far north as Quebec.

During the subsequent cooling period and southward migration of species, some of the southern species survived in the Pinelands. The alternating warm and cool climatic changes occurred when there were no artificial barriers to species migration and no significant human destruction of habitats.

The climatic and migration factors are reflected in the present Pinelands resources in three ways. The flora and fauna have an unusual composition of southern species that reach the northern limit of their range in the Pinelands, northern species that reach the southern limit of their range here, and species common to surrounding areas in the state. Many of the unusual Pinelands plant and animal species have geographical ranges that are discontinuous (disjunct). For example, a species may be found only in the Pinelands, the Carolinas, and Florida.

Range overlaps have resulted in hybridizations among northern and southern species. Hybridization of pitch pine with three southern tree species which overlap its range in this area, and hybridization between species of northern and southern snakes are a few examples of this process.

Overlaid on the climatic factors just described are the interactions of the natural biological processes of competition, succession, and evolutionary adaptation with the Pinelands' particular resource components. Today's flora and fauna reflect the success of specific species in invading and maintaining themselves competitively in the particular habitats that characterized the Pinelands. Terrestrial plant species are adapted to frequent fire occurrence and sandy soils of low nutrient content and water-retention capacity. Aquatic species are adapted to acid waters with low nutrient levels.

Fire has greatly influenced the development of present patterns of plant and animal distribution in the Pinelands. Some plant species, by nature of their structure, are more insulated from heat than others and are therefore less susceptible to fire damage. Also, some trees and shrubs produce stem and/or root sprouts quickly after fire damage while others have little or no resprouting capability. Seeds of some plants are destroyed by fire. The seeds of others are released when exposed to the heat of fire and germinate on relatively bare, burned-over soil rather than in a thick litter of leaves. Fire damage which produces major changes in the surface litter also affects the community composition of soil arthropods, bryopbytes, and lichens. Changes in plant communities caused by fire affect the structure of the animal communities which exploit the Pinelands.

Fire can be a common natural phenomenon caused by lightning and spread by high winds. It is believed that modern plant populations in the Pinelands have evolved in the context of a fire-adapted, low- nutrient, droughty ecosystem. The native species in the Pinelands are highly flammable, yet highly resistant to killing by fire. Most native upland species other than mosses and lichens sprout from underground stems or roots if their tops have been killed back. Pitch pine, the most abundant tree species, is also the most resistant to damage and killing by fire.

In addition to fire ignited by lighting, fires were intentionally and accidentally caused by Indians and European settlers. The frequency, intensity, seasonality, and location of fire all play roles in determining its influence on species patterns. The moist lowland sites have been less affected than the uplands and often act as firebreaks. Cedars do not sprout after fire kill, but may regenerate their population on a burned site depending on several factors, such as availability of seed sources, surface litter, water level and lack of hardwood competition. Also, given appropriate conditions, burned-over hardwood swamps may be replaced by cedar.

A complex of factors such as fire, soil texture, low soil moisture, and low nutrient availability account for present types of upland forests in the Pinelands. The role of fire is controversial. Some believe that the present patterns of oak-pine, pine-oak, and pine plains vegetation represent various stages of succession that would lead ultimately to a mixed-oak forest if fire were eliminated. Another interpretation assumes that present plant patterns reflect a long history of evolutionary adaptation to both frequent fire disturbance and sandy soils low in nutrients and moisture. Under the latter assumption, the pine plains, an extreme form of a fire-adapted pine-oak association, may not revert for a long time to a pine-oak forest.

Natural factors other than fire disturbance have changed patterns of plant and animal distribution in the Pinelands. Habitat changes occur from disturbances such as wind throw, which may create openings in forests to be filled by sequential stages of successional vegetation. Natural or animal-caused changes in drainage patterns can convert uplands to lowlands or the reverse. Indians may have altered the natural relative abundance of animal and plant populations through hunting and other types of activities, but these actions left a small imprint as compared with those that followed the European colonization of the Pinelands.

From European Colonization to the Present

Though the patterns of species composition were established in the Pinelands through natural processes, the landscape of the Pinelands has been altered over the last 300 years by a wide variety of human actions. Some of these actions have caused such great modifications in particular habitats that changes in relative species abundance and distribution have occurred. Many of the human influences have resulted in a reduction in the Pinelands' habitat and species diversity. A few have added to the existing variety of habitats and species.

Whether fire became more or less frequent and more or less severe after European settlement cannot be determined. Early settlers intentionally set fires to clear land. Others were accidentally ignited. As recreational use of the Pinelands increased through the years, so did the occurrence of accidental fire. On the other side, interest in protection of human life and man-made structures brought improvements in fire control efforts over the years.

Both upland and lowland forests of the Pinelands were subject to extensive timbering up through the mid-nineteenth century when the demand for fuelwood and charcoal decreased. Coal replaced wood as a source of fuel, and the Pinelands' iron industry, the primary user of charcoal, faded out as Pennsylvania ore proved more economical. It is estimated that prior to this time, upland stands convenient to water transportation were clear cut every 25 years, and less accessible forests were probably lumbered every 40 years. From the time of early colonial settlement, cedar has been in great demand for lumber and posts. It has been estimated that by 1980, most cedar swamps had been clear cut five or seven times. There has been continued cutting of pine through the years of sawmills, piling, poles and pulpwood it appears that while thinning or partial cutting may favor the development of oaks, clear-cutting favors pine. This is important in continuing the pine-dominated composition in the Pinelands. On the other hand, cedar swamps have decreased, and those that remain do not contain the large- sized trees described in journals of early visitors of the Pinelands. Clear-cutting can favor regeneration of cedars if seed sources and other factors are favorable. But because cedars are shade-intolerant, thinning or partial harvesting of the overstory has favored the replacement of cedars by hardwoods.

The use of land for housing developments, industry, and highways, obliterates specific habitats and natural communities. The result has significant implications for the Pinelands. The reduction in natural ecosystems means that the relative abundance of habitats and species patterns is altered. On the species level, the result has been the extirpation of some species with others being classified as endangered or threatened.

Recently, attention has focused on perhaps the most important effect of landscape fragmentation in the Pinelands: the creation of discontinuities in the Pinelands' natural vegetation that make dispersal barriers for flora and fauna. Larger contiguous patches of habitat can support more species with a much lower probability of extinction and facilitate the maintenance of genetic variability.

In ways other than those already described, man's actions in the last 300 years have modified the Pinelands landscape and the natural habitats and have resulted in changed species patterns. As examples, draining of lowlands has decreased directly the amount of wetlands vegetation. Pollutants such as agricultural fertilizers, pesticides, herbicides, and organic and inorganic wastes, entering streams directly or seeping through the soils to groundwater and then to stream waters, have caused nutrient and pH changes that change the native flora and faunal species composition. Intensive recreation and use of off-road vehicles have compacted soils in some areas to the extent that native species cannot regenerate.

In some instances, modification of the landscape by humans has led to increased ecological diversity. Abandoned farmland will pass through a series of successional stages of vegetation types before reverting to forest. Edges of highways controlled by mowing also exhibit successional vegetation. Abandoned cranberry bogs and former bog iron, sand, and gravel mining areas have produced ponds, bogs, or swamp habitats. As in cut-over cedar swamps, unusual species of plants often are found in these modified environments.

Man has disturbed the natural predator-prey and plant-herbivore relationships that evolved in the Pinelands without human interference. As a new predator in the environment, the human hunter has eliminated certain species of the Pinelands fauna, such as the black bear, wolf, heath hen, and native turkey. The beaver was also eliminated, but efforts to repopulate it have been successful, and turkeys have been released recently. In addition, zealous plant and animal collectors including commercial dealers have reduced native populations of particular native species. Herbicides, insecticides, and other forms of artificial pest control have also changed natural ecosystem relationships.

Summary of Human Influences

Several observations can be made about the overall impact that humans have had on the Pinelands in the last 300 years. On the one hand, the degree of recovery from three centuries of cutting and burning of Pinelands forests is surprising. With a few exceptions, such as reduction in the areal extent of cedar swamps, the patterns of species distribution may be little different today than they were thousands of years ago. On the other hand, it is fortunate for the Pinelands landscape that more fertile land for agriculture existed around it in adequate supply, that the Pinelands were not located in the direct corridor of transit between New York and Philadelphia, and that mass transportation improvements still have not brought the area within easy communicating distance to either point.

The explosive population growth that occurred in New Jersey starting in 1850 and continuing to the present did not press on the Pinelands until the last two decades. In just that short time, viewed in the scale of the 10,000-year development of moderate flora and fauna, a number of modifications have been made in the natural landscape. But despite past human actions, the Pinelands exist today as a unique and self-maintaining ecosystem. As such, they reflect the results of complex interlocking relationships between biological organisms and particular habitat conditions that have evolved over thousands of years.