TITLE: Standardized Protocol for Transect Set-up and Palm Inventory for the DOPAMICS Research Program
AUTHORS: Julien Engel, Kevin Mabobet, Jean-Louis Smock, Marc Testé, Louise Brousseau

[DESCRIPTION]
We describe the protocol developed as part of the ERC-funded DOPAMICS research program for setting up transects and conducting palm inventories in three forested pre-Columbian sites in French Guiana: MC87 near Régina, the "Grand plateau" in the CNRS Nouragues Research Station, and Mont Galbao near Saül. 

The objective of this field survey was to assess the distribution of Neotropical palms and to conduct following geoarchaeological surveys, and soil and palm sampling. In each study site, a transect approximately 1,000 metres long was set up from a pre-Columbian ring ditch and extended through the surrounding landscape. The transects were positioned to span different levels of human occupation (from pre-Columbian ring ditch hills with strong evidence of human occupation, RH, to adjacent hills or slopes with no or sparse evidence of pre-Columbian occupation, AH) and different microhabitats (including well-drained terra-firme and waterlogged bottomlands). Palms were inventoried over a band of 20 metres in width around the central line.
 
This protocol is made open access under the Creative Commons Attribution License (CC-BY). It details the inventory strategy and steps, and the material needed with the aim to encourage future reuses of this protocol for the same or similar research purposes, and to improve the reproducibility of the research conducted. Reuse of this protocol must credit the authors and mention its DOI. 

 


[BEFORE_START]
Make sure the satellite phone and GPS batteries are fully charged.
Make sure that the laser telemeter is calibrated.
Gather all necessary materials, prepare the pickets and graduated ropes.
Weigh the materials before transporting them by helicopter.

[STEPS]
SECTION: Setting-up of the transect central line
3. Starting from the transect start:

Plant a picket at the start of the transect
Label the picket with a permanent marker (Picket ID= "Cstart")
Record the GPS position of the picket
Follow the direction of the transect's endpoint using a precision compass and mark the central line with a wire until you reach the end of the transect
Plant a picket at the end of the transect
Label the picket with a permanent marker (Picket ID= "Cend")
Record the GPS position of the picket.

 
 
 
SECTION: Setting-up of a 20-metre-wide band around the central line and quadrats
4. From the transect start,

Position the first graduated rope (100-metre long, with graduations every 10 meters marked with adhesive tape) along the central line (Y-axis)
Plant a picket at 50 and 100 metres along the central line
Label the pickets with a permanent marker and record their GPS positions.

 

With the 60-m measuring tape, 
Position the second graduated cord parallel to the central line, 10 meters apart, to delimit a band of 10-metre wide on the left side of the central line
Position the third graduated cord parallel to the central line, 10 meters apart, to delimit a second band of 10 meters wide on the right side of the central line.
 
Inventory palms within each 10 x 10 m quadrat (shaded area in Figure 3) →  see next steps "Palm inventory" and "Palm field phenotyping"
SECTION: Exploration of the study area
2. Survey the forest area surrounding the ring ditch hill:

Assess whether the target palm species are present on the ring ditch hill (RH) and in the surrounding  landscape. 
Inspect uprooting mounds at the foot of fallen trees to detect the presence of archaeological artefacts such as ceramic fragments and charcoals.

This preliminary evaluation helps determine the distribution of the target palm species and of pre-Columbian occupation in the study area to position the transect. Then,

Select an adjacent hill or slope (AH) at a maximum distance of 1km from the ring ditch with: (1) target palm species and (2) no or sparse evidence of pre-Columbian occupation such as earthworks, abundant ceramic fragments or other archaeological artifacts.

 

SECTION: Foreword: Overview of the transect design and target palm species
1.  
A ring ditch is a geometric earthwork of pre-Columbian origin that can be found in various forested areas of the Amazonian rainforest. It is typically an archaeological artifact whose function is still not fully understood. Ring ditches can vary in size, ranging from a few dozen meters to several hundred meters in diameter. They are particularly abundant in inter-fluvial areas of French Guiana (northeast Amazonia) but also in other regions of Amazonia, such as in northern Brazil or Bolivia.

Starting from the ring ditch with strong evidence of human occupation, the transect extends through the surrounding landscape, spanning different microhabitats including well-drained terra-firme of hilltops and slopes and waterlogged bottomlands.

 

SECTION: Palm inventory
5. Within each 10 x 10 m quadrat: 

Identify target palm species
 

Assign individual palms of the target palm species to a unique identifier ([palm-ID]) and label it with a plastic label.

 
 
 
 

 

Record the GPS position of the palm.
Assign the palm to a position in the forest layers, a categorical variable that describes the vertical position of individual palms : forest floor, understorey, sub-canopy. 

 

⇒ In the field notebook, note: [palm ID], [quadrat number], [species], [GPS point number], [position in forest layers]

SECTION: After end
10. After returning from the field:

Convert inventory data to electronic format using Excel or an equivalent program (file format: tab-separated .txt or .csv).
Export GPS data so that they can be loaded into Geographic Information System (GIS) mapping software, such as QGIS, on a topographic (IGN) and/or LiDAR-derived DEM background.
SECTION: Palm field phenotyping and phenological monitoring
6. Palm field phenotyping

Because the target palm species have different intrinsic characteristics, different descriptors are used for field phenotyping.

 

For Astrocaryum sciophilum and Oenocarpus spp.:

With the laser telemeter, measure the stipe height from the ground to the base of the crown (i.e. point of insertion of the lowest living leaf)
With the diameter tape (D-tape) or tree caliper, measure the stipe Diameter at Breast Height (DBH). 

 
 

 


 
For Euterpe oleracea : 

As E. oleracea often occurs in clumps, 
Count the number of stems (i.e. stipes) in the clump. If there is only one stem, count "1".
With a laser telemeter, measure the height of the tallest stem from the ground to the base of the crown (i.e. point of insertion of the lowest living leaf).
With the D-tape or tree caliper, measure the DBH of the largest stem.

 

For Astrocaryum paramaca : 

As A. paramaca is always acaulescent (stemless), 
With the measuring tape, measure the length of the longest rachis.

⇒ In the field notebook, note: [height], [dbh], [number of stipes], [length of the longest rachis]


8. 
 

SECTION: Palm field phenotyping and phenological monitoring
7. Phenological monitoring

Monitor the phenology of palms and encode it as follow: 

 

If the palm is fructifying, count the number of bunches, see figure 7. 

 
 

  ⇒ In the field notebook, note: [phenology], [number of bunches]
9. Repeat the operation every 100m along the entire transect.