Monday, January 11, 2016

Dominican Republic: A Story of Caves and Bats

"In the island, which I have said before was called Hispaniola, there are very lofty and beautiful mountains, great farms, groves and fields, most fertile both for cultivation and for pasturage, and well adapted for constructing buildings. The convenience of the harbors in this island, and the excellence of the rivers, in volume and salubrity, surpass human belief, unless one should see them"
Letter of Christopher Columbus to King Ferdinand and Queen Isabella of Spain, 1492

The heights of Pico Duarte (3098 m), and the Cordillera Central. Behind, the Chain de la Selle or Sierra Baoruco.

November 2004 found me on the island of Hispaniola. To my great pleasure and experience, I was more than very excited to go. His research concentrated on the study of a peculiar group of bats called natalids for his doctoral dissertation (see results here). That study entitled surveying and studying living populations of these bats in their natural habitats, and visiting the island of Hispaniola was essential.

Practically straight out of the plane, we were scouting for areas to set our mistnets and observe our first bats. On that first night, near the quintessential city of Santo Domingo, we captured a female fig-eating bat Phyllops falcatus (haitiensis), which was weighted, measured, and released. The efforts were rewarded by the company of researchers Adrian Tejedor, Kevin Murray and Nelson Marcano.

Fig-eating bat Phyllops falcatus (haitiensis) near Santo Domingo, Dominican Republic.

Next day, and after many hours of bureaucratic roundabouts, we set out west, across the mountains of the Sierra de Neiba and on to the Valley of Neiba on our way to Barahona. We were looking for a fisherman town called Los Patos, and a set of caves perched in the mountains of Barahona. Several other scientists had marked this location as a site of interest for bat researchers (Miller, 1916-1929), and we were following their footsteps.

End hills of the Sierra Baoruco, in the small fishermen town of Los Patos, near Barahona.

The caves 1 and 2 of Los Patos are almost vertical, inside the belly and atop the hills from which the ocean is visible. The rocks there are limestone conglomerates, which with time and erosion rolled down and covered the beach in a thick blanket of polished pebbles. Such surface made our sleep there somewhat uncomfortable, but the view was spectacular.

Los Patos beach, near Barahona, looking towards the Caribbean Sea.

View from the mouth of Cueva de Los Patos 1, over looking the Caribbean Sea.

Inside the caves laid examples of the ancient fauna, represented by delicate fossils. The floors had guano and the walls had bats. The species we observed included ghost-faced bats Mormoops blainvillei, large fruit-eating bats Brachyphylla nana, Artibeus jamaicensis, the pollen and nectar eaters Monophyllus redmani and Phyllonycteris obtusa, plus large-eared insectivorous Macrotus waterhousei. The bat and bird faunas were exquisitely diverse.

Cueva de Los Patos 1-2. Roost of large fruit bats Brachyphylla nana (pumila) and Phyllonycteris obtusa.

Large-eared bat Macrotus waterhousei. This is the large subspecies waterhousei, which lives on Hispaniola.

However, the natalids, Natalus major and Chilonatalus micropus, the goal of the expedition almost, eluded us. Our single Ch. micropus was caught late one night, as we were putting away the mist net. Just then came this low, butterfly-like, flying bat into the net. So far, this remains the only reported Ch. micropus roost site on Hispaniola (Tejedor, 2011: 35).

Chilonatalus micropus from Los Patos Cave 2

Under the chilly effect of the mountains, we headed back to Santo Domingo. On our way through the valley of the Cordillera Central towards the south, we stopped at Bani, birthplace of Maximo Gomez (1836-1905). Gomez was a brave and dedicated General of Cuban wars for independence between 1868 and 1898, and the later Cuban-Spanish-American War. Cuban history values the great contribution from this Dominican generalissimo (see fig. below).

General Maximo Gomez, early 1900s. From Library of American History, Vol.VII.

The roads crossing through the central valley of the Cordillera Oriental to Sabana del Mar, on the south coast of Samana Bay, were very deteriorated or non-existing, rough, and dangerous. But these were filled with interesting flora and fauna that we stopped to observe.

Hispaniolan giant Tarantula Phormictopus cancerides

One of our first encounters was this Hispaniolan giant Tarantula (Phormictopus cancerides), and one or two Ashy-faced owls (Tyto glaucops). While asking for directions in the town of Sabana de la Mar, we spotted a large bat flying around a light post in the main central park. We parked to take a closer look. It must have been nearly 12 am, and we were dead tired, but stunned to see a large bulldog fisher bat (Noctilio leporinus) apparently eating insects attracted by the light of the lamp post!

Noctilio leporinus on the central plaza of Sabana del Mar. The white dots are likely insects captured in the glare.

Finally, that night we arrived a natural reserve station on the Haitises Park. The Haitises are a conglomerate of natural wonders. It has a high diversity both in fauna and flora, and interesting  formations called "mogotes" or in this case known as "haitises". These are conic karst hills, like the mogotes of my previous post on Pinar del Rio, western Cuba. These, however, are formed on younger limestone, smaller, and covered with more vegetation, but similarly impressive.

Conic karts, limestone formation of the Haitises as we saw them from our boat.
Courtesy and Copyright of Adrian Tejedor.
Conic karts, limestone formation of the Haitises as we saw them from our boat.
Courtesy and Copyright of Adrian Tejedor.

This variation of karst formation or karst geomorphology (as in geological manifestations of the terrain), was formed by dissolution of the limestone over time. In the Caribbean islands similar karstic formations are present, but most profusely in Cuba, Jamaica, this region of Hispaniola, and in Puerto Rico. However, they are all distinct in their level of maturity. The oldest and thus more mature are those of Pinar del Rio in Cuba, whereas those of Hispaniola and Puerto Rico are formed on most recent rocks.

Massive limestone haitises in the bay of Samana. One can almost imagine
how C. Columbus saw the Tainos right on these beaches he was there.

To get to these rounded hills, which from afar looked like elephants half submerged in the waters of the San Lorenzo bay, we had to ride on a small boat. This boat took our party along the crannies and crevices between the massive rock domes of the Haitises. We were looking for the intricate cave systems that honeycomb these formations, so important to our research since they were to host the fauna we sought.

Railroad Cave appears from within the drowned elephants that are the karst hills of the Haitises.

One of these caves was Cueva de la Linea, or Railroad Cave, known to us from the early research of William M. Gabb, William L. Abbott, Gerrit S. Miller,  and later that of Krieger (1928-29).

Railroad Cave is near an abandoned railway track near the bay of San Lorenzo. The area is surrounded by crescent sandy beaches, marshes, and caves. The most notable caves being  Simmons's Cave, Boca del Infierno cave (the Mouth of Hell), and Railroad cave, which is known locally as Cueva del Templo (cave of the temple).

William M. Gabb explored caves around this area between 1869 and 1871, finding extensive evidence of pre-Columbian inhabiting. Exploration continued calling the attention of William L. Abbott who explored several of these caves, including Railroad cave in 1883 and then in 1916. It was the former which enticed the National Museum to send Gerrit S. Miller later that year, and then again in 1928 with H. Krieger. It was this last party which carried out serious archeological and paleontological research there (1929).

Sunlit Cueva de la Linea or Railroad cave in Samana Bay.

The Ciguayan tainos inhabited these beach caves, and their former presence is felt by their many shell heaps (Strombus pugilis) at their entrances and the unforgettable cave art in their anterooms. The shell heaps also include the bones of the animals the Tainos used for food, such as hutias, manatees, conchs and fish, and are generally called kitchen middens in the archeological jargon. One can't help but imagine what Columbus saw when he visited the bay of Samana to observe an eclipse of the moon in 1492. Then, the natives lived on the north shore of the bay.

No doubt we enjoyed this particular cave much. The pictographs and petroglyphs, like those the figure below, carved into the cave rock, depicted faces, handprints, and sketches of animals like egrets, dogs, sharks, and others. Moreover, there were large bat colonies in very hot rooms separated by small water intrusions, deep into the cave system.

Ciguayan Taino petroglyph at Cueva de la Linea, Samana.
One of the many human artistic representations of the area.

Moving inside these hot rooms was uncomfortable because the extreme temperature and smell of bat urine made breathing difficult. Often we had to stop and hold on to the wet walls to catch our breath before moving on forward. In the center of these rooms, there were accumulations of bat excrements and all kind of invertebrate fauna that feeds on deceased bats and the guano on the floor. The same guano that is often mined as a natural fertilizer.

Natalus major in its roost, Cueva de Cristian, Hato Mayor.

A colony of the sought after Natalus major, inside a well-vented room Cueva de Cristian, Hato Mayor.

But what was the purpose of all this?

Fieldwork is not an easy task and is well accompanied by multiple difficulties that researchers must endure reaching their goals. From sleeping on cave floors infested with ticks and roaches, to having no food or commodities, to being attacked by the native fauna (people included).

It is sad that much destruction occurs well within the boundaries of several national parks and other areas. Illegal burning, cutting, and cave guano extraction threatens and disturbs the natural fauna. This includes the nests of the Palm crows, the endangered Ridgway's hawk, Hispaniola amazon parrots, natalid bats, and a myriad of plant life; living organisms in general, but especially those that are endangered or vulnerable already. Many of the well-forested areas are cleared for avocado, coconut, and plantain plantations or tourism. Therefore, it is important that we document the existing flora and fauna so that we can establish sensitive plans of protection, so that the wonderful areas are not lost to posterity, and that other may enjoy its natural wonders in the same way that we have.

Samana peninsula and San Lorenzo bay seen from atop one of the Haitises.
A scenery reminder of the natural wonders that must be protected from complete human destruction.
Once these are gone, they are gone forever.

The experience of research, not just traveling to exotic places to see interesting organisms, but with the hope of discovering something new, is very rewarding. In the end, our efforts are towards a better understanding of the natural environment that surrounds us all.

We think these environments and their organisms are worth preserving, but one blog cannot capture the natural complexity and beauty of these amazing islands. The world would surely be a dull place without these magnificent ecosystems. We should strive to protect them, instead of destroying them.

Cited Literature

Krieger, H. W. 1929. Archeological and historical investigations in Samana, Dominican Republic. US National Museum Bulletin, 147.

Tejedor, Adrian. 2011. Systematics of funnel-eared bats (Chiroptera: Natalidae). Bulletin of the American Museum of Natural History, 353.

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