Galapagos Trip 2023 -- Day 5 -- Santa Cruz Highlands

CAUTION   --  I KIND OF GEEKED OUT -- THERE ARE STILL LOTS OF PICTURES TO SCAN IF YOU GET BORED WITH THE SCIENCE

We had had a busy morning on Santa Cruz island, first visiting the Charles Darwin Research Station, then exploring Puerto Ayora including the Fish Market.  We had a very enjoyable lunch at Finch Bay Hotel.

Now it was time for our next adventure, a visit to the Santa Cruz highlands.  Specifically we were going to Rancho el Manzanilla, a ranch in the highlands, to look for giant tortoises.

The Turkey stalking a tortoise at Rancho el Mazanillo in the Santa Cruz highlands

As seen in the photo above, the vegetation in the highlands is totally different from the mangroves along the coast or the cacti and palo santo trees of the slightly more interior arid regions.  The highlands had thick grass, shrubs, ponds, and trees! 

Vegetation zones vs altitude.  Like the other islands in the archipelago, Santa Cruz Island was formed from a volcano, however now extinct.  The highest point on the island is 2,835 feet.  The existence of the mountain leads to the climatic phenomenon known as the rain-shadow effect:

Prevailing winds blowing across the ocean contain some moisture. When they encounter an island with high elevations, like Isabela or Santa Cruz, they are forced to rise. At higher elevations, they become chilled and their water condenses as rain or mist, which precipitates out at high elevation on the windward side of the island. On the leeward side, there is very little moisture left in the air and the climate is, if anything, more arid than normal. Thus, the larger island have a distinct zonation of moisture that forms the basis for its ecological communities.

Habitat zones as a function of altitude on an island such as Santa Cruz (https://www.geol.umd.edu/sgc/GEOL388/lectures/07.html)

The difference in rainfall vs altitude leads to different vegetation zones at different elevations (see diagram above).  

I believe all of the shore visits so far have been in either littoral (coastal) zones or in arid zones (roughly up to an elevation of 300 feet (91 m) on the southern sides and as much as 1600 feet (488 m) on the drier northern sides).  Both of these zones have little rainfall. 

Above the arid zone is the transitional zone, which is characterized by increasing moisture and hence more lush vegetation.  The scalesia zone, roughly 650-1300 feet (198-396 m), is the lowest of the humid zones and is named after the scalesia tree which grows at these elevations in dense forests. .

Below is a map of Santa Cruz Island with elevation shown by the colors.  The elevations near the center are clearly high enough for significantly greener vegetation than anything we had seen so far.

Map of Santa Cruz Island. El Chato is the location of another tortoise ranch.  Rancho el Mazanillo is SSE of the point labeled La Casseta. (By Bamse - own work, using:File:Ecuador Galápagos Islands location map.svg by NordNordWest, GFDL, https://commons.wikimedia.org/w/index.php?curid=49195398)

The Highlands--Traditional Home of the Tortoises.  The highlands are the home of dome-shaped tortoises.  Giant tortoises have long lived in the highlands and on the southern slope where the climate is wetter and the vegetation is more abundant.  Of course, humans looking for an ideal location for farming and ranching  chose this same area for much the same reason. 

When the Galapagos National Park was created in 1959, 97% of the land surface of the archipelago was set aside as a protected area.  This includes most of Santa Cruz Island (see below).  The remaining 3% was land already owned and in use by the human settlers.  It was to remain zoned for human use.  That included much of the Santa Cruz highlands as shown in tan below. 

Boundary of Galapagos National Park on Santa Cruz Island.  I think Rancho el Manzanillo is on the edge of the Impact Reduction Zone at the west end of the straight east-west boundary near the center. (https://www.scirp.org/journal/paperinformation.aspx?paperid=89472#return81)

However, the tortoises either did not get the memo or chose to ignore it.  The tortoises continued to live and migrate through the areas assigned to the colonists.  It has taken awhile, but it appears the two groups have found a way to live together.  Rancho el Manzanillo is one of three ranches/reserves (and the newest, I think) where tourists can view wild tortoises in the Santa Cruz highlands on what is essentially ranch land.

Drive to the highlands.  Below is the gps track of our trip on a topo map.  It was about a 10 mile bus ride from Puerto Ayora to Rancho el Manzanillo.  Our bus followed the main road out of Puerto Ayora, It is mostly the ONLY road.  It eventually goes as far as the ferry to Baltra Island where the airport is located. 

Away from the water it was an immediate and steady uphill climb.  As soon as we got away from the first few block from the water, we were into the non-tourist area of town with houses, schools, a large soccer field, etc.  

As we got further from downtown the contrast between the very upscale homes in German town we had seen earlier and the homes here was stark.  Most of the homes were cinder block.  Many were unpainted.  Many of them had what looked like rebar sticking out of the top of the building, leaving an unfinished top floor.  Our guide commented on this, indicating they had been left partly unfinished until the occupants could save enough money to finish them  It is so common that this article refereed to the architecture style as "permanently unfinished".

At some point, probably after the left turn at Bellevista, it became ranch land with scattered homes.  There were multiple fields of grass enclosed by barbed wire with a few cattle.  There were also a few small stands of plants that I thought might be bananas.  In any case, the area obviously has more rainfall than lower elevations.  That is consistent with an elevation of 624 feet at Bellevista on my gps.

I don't know the speed limit, but we moved right along except for intermittent speed bumps.  I also noticed there was a bike/walking path parallel to the highway but somewhat separated.  Despite the long uphill grade, I saw multiple people on bikes with packages.  It looked like the bicycle was likely their normal means of transportation.

GPS track of our trip

Side road  to Rancho el Manzanillo.  A few miles further we came to the turn off to Rancho el Manzanillo  My gps had an elevation of 1213 feet at the turn off, which should have been the scalesia zone.  However there were no scalesia forests here.   Everything had been cleared for agriculture decades ago. 

The drive back to the ranch was a  downhill drop on an unpaved road.  By the time we reached the parking lot, my gps was back down to 600 feet elevation.  We stopped multiple times due to tortoises in the road.  There were barbed wire fences on either side of the drive in most places, but they were not to contain the tortoises.  The bottom strand was set high enough to let the tortoises pass under.  

This is not our picture, but I believe it is the same entrance road.  Note the tortoise crossing sign.  (https://www.metropolitan-touring.com/blog/nature/giant-tortoises-highlands-santa-cruz/)

Rancho el Manzanillo.  Despite the tortoises in the road, we made it. The first order of business was moving to the open pavilion where we got rubber boots.  It was very reminiscent of getting bowling shoes.  We each asked for a size and they pulled a pair off the shelf. 

I was very glad for the boots.  It was not terribly wet or muddy the day we were there, but our shoes would probably have gotten wet from all of the tall grass. What is not apparent in any of the pictures are the MANY rocks (dare I say boulders) often as big as bowling balls hiding in the long grass that made walking a challenge.

With boots on we were off.  Almost immediately we began to see tortoises. 

Tortoises were randomly scattered around.  This was immediately in front of the parking lot.

The tortoises were totally wild, but could care less about humans.

He just kept munching away on the grass despite the crowd watching him

Grass hanging out of the left side of his mouth

Tortoises are ectothermic (proper name for "cold-blooded"), unable to metabolically generate body heat.  However, adult tortoises can maintain a relatively stable body temperature by behavior alone, i.e. moving into sunlight to warm up, moving into the shade to cool down, or possibly submerging in mud or water.  Several of the tortoises were taking advantage of a small muddy pond.

One of the tortoises was on his way into the water.  Notice the duck standing near the edge.

Sometimes tortoises will sleep overnight in the water because it helps regulate their body temperature.

This guy had worked his way down into the mud

Most of the tortoises we saw were wandering around munching on grass.  I don't know which is more interesting, the tortoise munching on grass...

Not sure how easy it is to see, but the white streaks on his chin are stained green from the grass

...or all the people watching him.

Most of the tortoises were chilling out, but some seemed to be in a hurry to get somewhere.  This one seemed to be on a mission.  These shots taken one after another make him look like he is really moving along.

 

 This video below is of him at normal speed, NOT slow-motion.

He may have been in a hurry, but hurry and fast are not the same thing.  Top speed for a Giant tortoise is about 0.2 mph.  However, even at that speed they can travel as much as 4 miles in a day.

Migrating to the Coast.  Although the tortoises spend a lot of time in the highlands, they do migrate between the highlands and the coast.  Importantly, the females lay their eggs on the coast.  Each female may lay several clutches.  Development is slow and eggs must incubate anywhere from four to eight months. Once hatched, the small tortoises live at lower altitudes, but eventually wander to the higher altitudes.  They reach sexual maturity at 20-25 years and are full size by age 40.  However, I could never find out at what age they typically return to the highlands.

Below is a map showing the gps tracks of some tortoises on Santa Cruz Island migrating between the  the highlands and the coast.  I think the easternmost set of tracks at the bottom likely include those at Rancho el Manzanillo.

Santa Cruz Island vegetation zones.  Black lines are gps tracks of migrating giant tortoises.  (https://phys.org/news/2012-11-galapagos-tortoises-migrating-species.html)

 

Why go to the coast?  As I was reading about all of this, I kept wondering why the tortoises bothered to migrate.  Why didn't they just stay in the highlands where it seemed living was good. I finally found this explanation in the book Galapagos: A Natural History, 2nd Edition, by John Kricher and Kevin Loughlin, page 137 (my underlining):

In recent years it has been learned that in many reptile species, sex is determined not chromosomally, as in birds and mammals, but essentially by the temperature at which the eggs are incubated while buried.  This appears to be the case with Galapagos tortoises. Research at the Charles Darwin Research Station has shown that embryos become males if the incubation temperature is less than 83 F (28.5 C).  Higher temperatures influence embryos to become female.  Recall that the tortoises bury their eggs in the lower and hotter zones found on the various islands.  Both males and females can be produced in a single nest because the actual egg temperature may vary somewhat based on the position of the egg in the clutch.  It is obvious as to why female domed tortoises must migrate to the arid lowlands for nest building. Were they to nest in the cool highlands, eggs would take much longer to incubate, many would perish from the cold temperature, and any that hatched would be males.

Interesting Flora.  Obviously our focus was primarily on the tortoises, but we still couldn't get over all of the lush green foliage so obvious in these shots.

 

 

Some of the trees looked like they had Spanish moss.

In one particularly wet area near a pond, the ferns were impressive.

Even though we were probably low enough in elevation that we were in the transition zone rather than the more humid scalesia zone, there was obviously a good amount of moisture here.  The plants were impressive.

If only the tortoises could tell their story.  Still, it was the tortoises I keep thinking about.

If only he could talk, I wonder what he would say.

Although mariners had been stopping at the islands for centuries, the earliest settlers came to Santa Cruz Island in the mid-1930's.  Presumably the highlands would not have been settled and cleared for agriculture until then or later, i.e. no more than about 90 years ago.  Giant tortoises can live 100-150 years or even longer.  Not only could the same families of tortoises have been coming back to this same location each year since before humans cleared the land, but the very tortoises we were interacting with, if they are older, may have been coming to this spot since then.  No wonder they acted like they own the place!

Iced tea, gift shop, and coffee farm??  We had really enjoyed wandering around looking at everything, but it was getting late.  We made our way back and handed in our boots.  Then we went to the beautiful open air restaurant and enjoyed some iced tea and downtime.

Paul tried out one of the hammocks

After someone mentioned how nice the gift shop was, we dashed over and found some t-shirts. 

It was only after I was home that I discovered online that the owner of Rancho el Manzanillo  (at least some time in the past) grew coffee on the property.  Coffee grown in Galpagos is supposed to be to die for.  However it is very hard to find.  After all, space for agriculture in the islands is very limited.  I did not see any such coffee for sale in the gift shop, but I wasn't looking for it.  If it was there, don't tell me.  I will never forgive myself for not getting some if it was available.

By the time we finished in the gift shop, the guide was pacing in front of the bus wondering where we were so we clamored aboard and the bus took off for Puerto Ayora.  We were soon back at the passenger dock.  While we waited at the dock for the pangas to take us back to the ship, the sun was setting, the temperature was coming down, and the entire area was coming alive with people. 

Of course there were also wildlife to watch.  There was a pelican who had a favorite spot on the dock railing.  He would watch intently, then dive into the water.  I don't know if he ever caught anything, but we sure enjoyed watching him.

Pelican watching for fish at the passenger dock in Puerto ayora

It had been an extremely busy day, but we had seen and learned so much.  We only had one more full day to go, but it was something I had been looking forward to seeing, Post Office Bay.