Northshore Restoration

Northshore Restoration and Urbinazation

There are efforts on the Northshore for restoration, conservation and land acquisition to protect the important ecosystems and habitats in the region. However, further action on the Northshore is needed now. With expanding populations causing pressure for development and synergistic anthropogenic and natural activities stressing natural ecosystems, people must begin to think about conservation and restoration as a necessary part of community planning. The Northshore has a chance to include the environment and natural areas as part of community and urban planning in order to simultaneously expand the population and economy and protect the natural areas that attracted people to the area in the first place. The Northshore community has the unique opportunity to consider natural areas as it expands and arrive at solutions that work for both human and natural populations and to consider both as funding opportunities arise. The Pontchartrain Conservancy wrote the Lake Pontchartrain’s Northshore: Recommendations for Restoration and Conservation report to give recommendations for areas that should be preserved or restored.

Board walk in Big Branch National Wildlife Refuge, one of the conservation areas on the northshore.

Northshore Population Growth

Population growth and community expansion continues worldwide. Urbanization often occurs at the expense of natural ecosystems. The Northshore of Lake Pontchartrain is currently one of the fastest growing communities in Louisiana. Population in Tangipahoa Parish increased 26% and in St. Tammany Parish increased by 28% from 2000 to 2014, with a large population influx after Hurricane Katrina. From 1982 to 2000, urbanization was responsible for the loss of 5,400 acres of marsh, 6,700 acres of wetland forest and 30,630 acres of upland forest. The population growth leads to urbanization, putting pressure on the natural areas of the Northshore including unique habitats such as rare long leaf pine savannah.

Northshore Existing and Priority Conservation Areas

The Pontchartrain Conservancy and The Nature Conservancy have jointly identified some areas on the Northshore that should be a priority for conservation. The priority conservation areas were chosen because they contribute to the ecological integrity of the region and often include riparian or marsh areas . The priority conservation areas listed do not include much upland forest because much of this habitat occurs north of I-12 or outside of the coastal zone. However, upland pine savannahs that are found north of I-12 should not be developed as they are a unique habitat and support species that are unique to the region.

Priority conservation areas on the Northshore, as delineated by Pontchartrain Conservancy and The Nature Conservancy, where development should not occur.

Northshore Issues

Historical Logging

There is a history of logging on the Northshore, especially in the swamps of Tangipahoa Parish. Swamps were heavily logged for cypress lumber due to the Timber Act of 1876, in which swamps were declared unsuitable for cultivation and not purchasable for private ownership. Under this act, large tracts of land were sold for low prices (25 to 50 cents per acre). Logging reached a peak during early 1900‟s as pull-boats mechanized the industry. Large logs were pulled to open water creating a series of small ditches while larger canals were dug to accommodate the pull-boats. By 1929 it was announced that the available timber in the area was exhausted and logging operations moved elsewhere although log mills stayed in business to process lumber already cut. The result of the intense logging was the loss of swamp forests as well as the biota that lived within. Much of this area is now relict swamp, forest that stands now but is dying and not reproducing.

Typical radiating logging ditches that remain on the landscape almost 100 years after the logging ceased.

Urbanization

Many of the Northshore habitats have been cleared and converted into the urban land-use. This is especially true of the more upland habitat types like pine forest. From 2005 to 2008, the Northshore experienced rapid population expansion and therefore rapid urbanization. Between 2005 and 2008 alone, 2,620 acres of upland, 1500 acres of wetland forest and 1,430 acres of marsh were lost in the area south of I-12, from I-10 to I-55 and south on the Maurepas Land bridge to the Tangipahoa Parish line. Of this total of 5,550 acres of habitat loss, 2,230 acres or 40% was lost to urbanization. An additional 1,340 acres or 24% was lost to Ag/Grass/Barren, which often results from the clearing of land in anticipation of development. Uplands contributed to 35% of the urbanization. Wetland forests and marshes were negligible in the contribution to urbanization. These habitats types were lost to other processes such as impoundment, subsidence and salt water intrusion. This indicates that much of the development occurred on ag/grass/barren lands that were mostly likely cleared prior to the study period in anticipation of development.

Click here to see zoomed in examples of urbanization between 2005 and 2008 on the northshore.

Northshore land use in 2005 and 2008. Areas of expanding development can be seen over the three years.

Nutria

Nutria (Myocaster coypus) was introduced into Louisiana marshes in the early 1930’s through accidental and intentional releases in some cases to supplement the muskrat fur trade. In the 1940’s nutria were promoted as a biological control agent for the invasive plant water hyacinth (Eichhornia crassipes) which led to the transplantation of these animals throughout the southeast. The nutria population continued to grow and was estimated to be 20 million in Louisiana at its peak in the late 1950’s. Nutria are known to be extremely detrimental to marsh and swamp habitats. In marshes, they generate “eat outs” or large areas denuded of vegetation by nutria during foraging. Nutria often feed heavily on plant roots and rhizomes of many native plants making them wasteful feeders since eating the roots causes plant death but they discard the rest of the plant. In addition to these large eat outs, the nutria also damage baldcypress forest by girdling mature timber and eating seedlings. While girdling of large trees is not a large problem as it does not commonly lead to death, seedling consumption by nutria prevents or slows the natural regeneration of the forest and also impacts restoration projects involving seedling plantings. They damage seedlings by pulling them up and eating the taproot or by eating the emergent vegetation to ground level. With the abundance of nutria increasing shortly after logging decreased, the natural post-logging regeneration of the cypress forests could have been severely impacted by the high nutria populations. There has been a reduction in damage by nutria across the coast since the Coastwide Nutria Control Program began in 2002. Commonly known as the “nutria bounty” the program offers money per harvested nutria turned into the program, generally $5 a nutria.

The map shows where nutria have been harvested since the inception of the Coastwide Nutria Control Program in 2002 (left). Over 4.3 million nutria have been harvested. Nutria, with characteristic orange teeth and rat tail, cause damage to marsh and forested wetlands by eating the roots of marsh vegetation, girdling trees and destroying seedlings (right).

Saltwater Intrusion

Saltwater intrusion occurs because of man-made canals that provide direct conduits for saltwater to enter fresh and intermediate marsh, swamp and bottomland hardwood forest as well as deficits in freshwater entering ecosystems which would normally help keep the saltwater at bay. Saltwater intrusion also occurs during storm surge events when saltwater is pushed overland and into impounded areas where the saltwater cannot drain out. Saltwater then becomes stranded and kills the vegetation.

Man-made canal connecting the Tchefuncte River to an impoundment to the west. When salinities rise in the lake or storm surge occurs, this canal carries saltwater into the interior of the mashes (left). The Guste Island area west of the Tchefuncte River is a series of failed agricultural impoundments which now strand saltwater and alter the hydrology (right).

Altered Hydrology

There are numerous hydrologic alterations across the Northshore coastal zone. These inclued historic logging canals, navigation canals, impoundments, and raised railroad beds that block or prevent overland flow through marshes. Many of these alterations cause water to drain out of marshes too quickly, cause water to pool and become standing water or are conduits for saltwater to enter the marshes.

Roads and development built through Big Branch marshes. These alter hydrology and affect overland flow (left). Old railroad bed that passes through Joyce Wildlife Management Area which impedes and alters overland flow (right).

Northshore Restoration and Conservation Recommendations

Expand Existing Conservation Areas

The acquisition of land for conservation can be difficult but is important to maintain some lands for future generations in a way that ensures the existence of the natural ecosystem.

It is recommended that the Joyce WMA be expanded to include the mouth of the Tangipahoa River and surrounding forests and marsh, the eastern side of Bedico Creek up to the Parish line and the coast line. With this acquisition the entire southern portion of both the Tangipahoa River and Bedico Creek would be under management and conservation. This will help ensure preservation of the entire swamp and marsh system in the area. With the coastline under the WMA system, preventing development of the coastline may be easier. Development on the coastline would affect the interior marshes as well as destroy the cypress coastline that exists and is currently maintaining low erosion rates. Protection of the entire system from the swamp to the marsh to the coastline would be ecosystem-wide. The recommended land acquisition for Joyce WMA will help to accomplish the preservation and restoration of important swamp habitats in the Tangipahoa sub-area and will contribute to the maintenance of the integrity of swamps in the surrounding area.

Big Branch National Wildlife Refuge was formed with an acquisition boundary outlining the maximum extent that could be acquired in the region. Within the approved acquisition boundary established in 1994 , which is 24,000 acres, 17, 366 acres currently are part of the refuge leaving 6,634 acres available for acquisition. When land within the acquisition boundary becomes available from willing sellers, it should be prioritized by the quality of land and the ability to support refuge resources and funding should be sought. In addition, it is recommended that the refuge acquisition boundary be expanded to include pine forests to the north and other area of conservation priority.

Recommended area of expansion for the Joyce Wildlife Management Area.

Protect and Expand Riparian Buffers

Riparian zones are located at the land/water interface along rivers or bayous. Riparian zones are important for trapping and removing sediment from waters during overbank flow, reducing stream bank erosion, removing nutrients, contributing detritus to the stream system, flood water storage, floral and faunal diversity, and moderating stream temperatures and water quality. Several studies have indicated that an effective riparian buffer, one that provides sediment reduction, adequate habitat and nutrient reduction, should be 100 to 300 feet. Along rivers and bayous are natural high areas with stable soils that provide adequate substrate for tree growth. Riparian areas can be thought of as a conservation bargain, being relatively narrow, unsuitable for most land uses and providing a large amount of services.

Historically, there was woody vegetation along the major rivers and bayous. These areas acted as a transition zone between the water bodies and the surrounding marsh and swamp. While there was some species overlap between the swamp and riparian vegetation, there were different species in the riparian zone since it is at a higher elevation, providing diversity of habitat ahd food sources for animals. Many areas no longer have any riparian zone or only a very narrow one. The lack of vegetation results in increased bank erosion and during storm events this erosion can be severe. This results in the widening of the channel and increased sediment input into river waters.

It is recommended that these important marginal areas be restored through plantings and protection. Along all water bodies, it is recommended that planting occurs to restore the riparian zone where it had been narrowed significantly or removed. Riparian zones should be established and new construction and significant tree harvest disallowed .

Riparian zones are very narrow or non-existent due to development and clearing along many waterways on the Northshore. Examples are shown along stretches of the Tangipahoa River (left), Lacombe Bayou (middle) and Bayou Bonfouca (right).

Marsh and Forested Wetland Restoration

Northshore marshes and forested weltands are diminishing in some areas and restoration efforts should be taken to restore these habitats and prevent further degradation.

Swamp restoration needs to take place on the Maurepas Landbridge. Much of the swamp in this area is degraded. Since the closure of the Mississippi River Gulf Outlet (MRGO), the conditions in the Maurepas area may have improved for swamp habitat as salinities have lowered. PC has been planting swamp trees in the region since 2012 to jump start the restoration but large scale restoration is needed.

Some marshes on the Northsore also need restoration or maintenance, especially in Big Branch Marsh National Wildlife Refuge, Guste Island, and the Tchefuncte marshes. Types of restoration that can be implemented to restore the marshes include annual prescribed burns over 1,000 acres of dense marsh to increase the plant diversity and create more wildlife habitat, restore marsh in areas where ponds reach more than five acres which would be accomplished through projects of dedicated dredging, and, terracing, with subsequent plantings of marsh vegetation, and fortifying the shoreline to prevent erosion into coastal marshes.

A large marsh creation project was undertaken at Goose Point and Point Platte and finished construction in 2009. This project has been very successful, creating 417 and nourishing 155 acres of marsh and is an example of the type of marsh creation projects that can be implemented elsewhere on the Northshore.

Goose Point and Point Platte in 2007 before marsh creation project began (top) and in 2015, 6 years after project completion (bottom).

Backfill Channels

Hydrology on the Northshore is often interrupted by canals. Historic logging and navigation canals prevent overland flow in the marshes, preventing freshwater and nutrients from rain runoff from reaching many areas. They also provide conduits for saltwater to intrude and pathways of rapid drainage out of the marshes.

Along the coast of the Northshore there are many shoreline canals that contribute to shoreline retreat by enhancing shoreline roll back. With large open spaces behind the shoreline, the integrity is weakened and the shoreline is more likely to retreat. These canals also contribute to greater damage when shoreline breaches occur.

It is recommended to backfill historic logging canals, especially those that radiate in a wheel spoke fashion, to improve hydrology. Other larger man-made canals should also be backfilled if they are not used extensively by local residents for recreation. The backfilling will help to force overland flow which will introduce freshwater into areas that do not normally receive it during flooding events. Filling canals that run parallel to the shore just behind the shoreline is also important. In areas where a marsh shoreline exists, restoration of a tree shoreline should be attempted in order to stabilize shoreline retreat. Exposed marsh shoreline does not hold up to wave action and erodes much more quickly than a tree shoreline.

Various locations in the East and West Tchefuncte Marshes where man-made canals could be back-filled to improve hydrology.

Canals along the Northshore shoreline that should be back-filled. These canal increase the rate of shoreline erosion.

Restore Hydrology

Many of the restoration techniques described above involves ways to restore Hydrology, such as backfilling canals. However, many other hydrologic restoration techniques could be implemented. Removing barriers to flow such as historic railroad beds or roads would increase overland flow. Where removal of these structures is not possible then culverts or other mechanisms to connect the wetlands on both side of the impediment should be installed. Removing spoil banks that are no longer needed will also improve hydrology by allowing bayous to flood into adjacent marshes.

Overall, restoring hydrologic processes will provide a jump start to wetlands restoration in the region and may decrease the need for further restoration.

Control Nutria

It is recommended that nutria populations be controlled by multiple means including trapping, hunting and natural biological control in order to promote wetland recovery and growth. While trapping still occurs, the price of pelts has fallen, so the incentive to trap these animals is not as high as it was during the 1970’s and 1980’s. The Coastwide Nutria Control Program (CNCP) was established in Louisiana in 2002. The goal of the program was to remove 400,000 nutria annually statewide. Registered participants are offered money per nutria tail brought to collection stations. In conjunction with collection of nutria tails, the program also takes data on method of collection, locations, how the carcass was used or disposed of and the month of harvesting. While the incentive program for trapping nutria has had success in reducing nutria populations, the program relies on self-participation which can be very unevenly distributed across southern Louisiana. It is also important to reduce nutria populations by biological control, through natural predation. The most likely predator of nutria are alligators.

Predation by alligators is a natural method for nutria population control. Alligators are known to commonly feed on nutria where they are available, once they reach over 6 feet in length. In Louisiana the diet of adult alligators is dominated by nutria and muskrat. Harvesting large numbers of big alligators eliminates alligators as a natural biological control agent on nutria. It is recommended that alligator harvest be suspended in Joyce WMA and surrounding swamp to allow large alligator populations to rise and grow to a size where they can successfully prey on nutria. Once populations of large alligators reach a high enough level, some harvesting may be allowed. It is important to emphasize that current alligator harvest limits are sufficient to sustain the species in the wild, and LDWF works hard to ascertain accurate nest numbers and set harvest limits to protect the species. The current management has successfully addressed the historical decline of alligator, but does not address the current problem of decline of cypress-tupelo forest. Therefore, where nutria are a problem and are damaging swamp and marsh habitat or preventing the restoration of these habitats, alligator harvest should be limited, especially the taking of large alligators that can consume nutria.

Large alligators, greater than 6 feet, can consume nutria and help keep their populations low.

Resources

Lake Pontchartrain's Northshore: Recommendations for Restoration and Conservation