San Lorenzo Forest – Panama

“If we want to understand and conserve life on Earth, we had better start understanding and conserving the arthropods of tropical forests.”

Terry Erwin, an entomologist at the Smithsonian Institution’s National Museum of Natural History in Washington, D.C.

Map of San Lorenzo National Park
Map of San Lorenzo National Park

The San Lorenzo Protected Area covers 12,000 hectares in Panama.  It is one of Panama’s newest protected areas and encapsulates the luscious San Lorenzo Forest.  The area also envelops a former U.S. military base as well as the ruins of a Spanish fort: San Lorenzo.  Troops headed for Vietnam and other jungle conflict areas trained in the San Lorenzo National Park.  In 1997 the ‘Land Use Plan of the Interoceanic Region’ formed the San Lorenzo Protected Area by law 21.

San Lorenzo
San Lorenzo

The Forest

9654 hectares of the San Lorenzo National Park covers tropical forest, rivers, wetlands and pastures as well as 12 miles (20km) of coastline.  The Park is located at the Northwest entrance of the Panama Canal and spreads over its west bank off of the Atlantic coast. This area acts as the biological corridor, running the length of Panama it allows wildlife to move between larger areas of forest at will as much of the land to the east and west of the corridor has been deforested.   It is an essential area for the Mesoamerican Biological Corridor which runs the length of Central America and is also the northernmost area of the north to south corridor between the Atlantic and Pacific oceans.

San Lorenzo Forest
San Lorenzo Forest

The San Lorenzo area has more hours of sunshine per day on all months of the year (except for January and February) compared to the Pacific Coast of Panama.  The San Lorenzo area also gets twice the amount of rain as the Pacific Coast.  This makes it possible for scientists to research how different climates can affect one similar area in a very small space.

The Chagres River – San Lorenzo

There at least 12 different types of forest in the San Lorenzo Protected Area, most of them high-humidity ecosystems.  These include semi-deciduous forests, moist forests, floodable cativo forests and mangroves.  Although San Lorenzo is considered to be a relatively small forest area, it has a very high level of biodiversity.  This includes over 270 species of birds; such as the Cattle Egret, Ruddy Ground-dove, Orange-chinned Parakeet, Blue-headed Parrot, rainbow-billed toucan and the Blue-gray tanager.  Mammals such as jaguars, boars, ocelots and Tapirs as well as reptiles like crocodiles, boas and iguanas also reside in San Lorenzo alongside the insects and foliage.

Slaty-tailed Trogon (Trogon massena) – San Lorenzo
Slaty-tailed Trogon (Trogon massena) - San Lorenzo
Slaty-tailed Trogon (Trogon massena) – San Lorenzo
Gartered Trogon (Trogon caligatus) female – San Lorenzo

Groundbreaking Research in the Forest

The first ever insect census was completed here at San Lorenzo National Park in 2003-2004.  102 scientists sampled every arthropod from the soil to the canopy over a period of 2 years, and sent them out to laboratories all over the world for identification, which took a further 8 years to complete.  In total the field team managed to collect 129,494 arthropods (previous studies by other scientific groups have only ever collected a few thousand) and 6144 different species of arthropods from an area of forest hardly bigger than half a rugby pitch; 0.48 hectares.  This research has led to the estimation through extrapolation that the San Lorenzo forest is home to 25,246 species of arthropods!  It is estimated that 60-70% of these species will be previously unknown, and that around 60% of these species can be found in any given hectare of the forest.

San Lorenzo
San Lorenzo

However, as Terry Irwin, an entomologist (not involved in this study) said ‘ To take a little sample from one place and scale up, it’s been critiqued and critiqued and it just doesn’t work.’  This means that the extrapolated estimate that the team of scientists came up with may actually be far from accurate.  The team also concluded that the species richness of plants closely reflected the overall number of arthropod species, indicating that plant counts could give a more accurate way of determining arthropod diversities over larger areas. For every plant species, there were around 20 arthropod species thus by knowing the former you can predict the latter to within 1% accuracy.  It is far easier to have a fairly accurate estimate of number of tree species than arthropod species, and thus if the methodology is repeatedly tested this could set the standard for estimation of arthropod species in a given area.

San Lorenzo
San Lorenzo

This kind of research can assist scientists in determining additional factors that influence biodiversity thus making it possible to determine the impact of habitat loss on arthropod species. It is also essential in helping to set conservation priorities, as scientists can begin to assess how adding or removing one particular tree or animal species, or any other factor can influence the balance of organisms in the area.

San Lorenzo
San Lorenzo

You can read the full report here

http://www.sciencemag.org/content/338/6113/1481

The Fort in the Forest

San Lorenzo Forts
San Lorenzo Forts

The  ‘Castillo de San Lorenzo el Real de Chagres’ or ‘Fuerte San Lorenzo’ for short is located in the North of the Protected area on the edge of a rocky cliff 25m above sea level, looking over the Caribbean coast and the Rio Chagres.

The original wooden fort was destroyed in 1671 during battle; it was rebuilt in stone in 1680 and yet again destroyed in 1740.  The ruins that are visible today are those of the 1768 rebuilt fort with further additions built in 1779.  These ruins were declared a UNESCO World Heritage Site in 1980.

San Lorenzo Fort
San Lorenzo Fort

The original use of the fort was to protect this river entrance from invaders and pirates.   Fuerte San Lorenzo was abandoned by Spain in 1821 as Panama became independent; its new function was that of a prison.  After this, it became the entry point for incoming mail from England to Latin America and since then it has become a tourist attraction in panama, as one of the oldest and best preserved forts in the world.

San Lorenzo Fort
San Lorenzo Fort

U.S. Military Base

Before Fort Sherman was a military base, in 1849 it was utilised as a camping ground for explorers and opportunists during the gold rush.  Fort Sherman was established by the United States in 1911 in order to protect the Atlantic entrance to the Canal.  From 1953-1999 the US Southern Command Jungle Operations Training Battalion was located here and the entire protected area used for jungle training by the US Defence Department.  During the First World War, batteries were built on the San Lorenzo Protected Area, including Fort Sherman, which were used for military training until 1999 when changes in war technology made them obsolete.

Fort Sherman 1973
Fort Sherman 1973
Fort Sherman - Military Activity
Fort Sherman – Military Activity

Agent Orange was first used here, at Fort Sherman.  It is the devastating chemical weapon that caused the deaths and maiming of hundreds of thousands of people during the Vietnam War, and is still causing disabilities and defects in newborns today.  There are still chemical contamination and unexploded landmines in the forest around the fort, but fortunately the National Park is not located near any of the contaminated areas.

Former Housing at Fort Sherman
Former Housing at Fort Sherman

San Lorenzo – A place for biodiversity and pirates.

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6 Comments

  1. I collected insects and butterflies here in the late 1970’s while stationed at the School of the Americas. It’s good to see it’s protected, but they are building a huge new bridge (like the Bridge of the Americas) over the canal and this will open up the entire Atlantic coast, from Colon to Bocas del Toro, to development. Sad to see.

  2. I was there in the fall of 1977,upon returning to Fort Campbell,Ky.myself and 10 others were quarantined at the Fort hospital.I believe the name was Womack. Is there anyone else out there who was there at that time and quarantined
    also? I was with the 326th Engr. Bn. CO. C

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