Field photo (left) and satellite image (right) of one of the sites I visited, which is representative of the Acacia-Commiphora shrubland of the Hawd in the southern parts of Somaliland.
Changes in water availability during seasonal drought affects vegetation growth over the full year and drives changes in carbon uptake. But, the effects of droughts in semi-arid ecosystems are difficult to isolate in time and space, and it is difficult to quantify their duration, magnitude, and spatial extent using broad metrics. In March 2022, I took a scoping trip to central Somaliland to inspect possible locations for a pilot network of autonomous environmental sensors to provide baseline information on microclimate in this data-deficient region. Specifically, I plan on combining local-scale measurements of soil moisture, soil temperature, air temperature, and tree growth with satellite-observed vegetation index data from the Copernicus Sentinel-2 satellites (10-meter spatial resolution, 5-day temporal resolution).
The five sites where the sensors will be installed.
We visited four sites out of the planned five (see map), the sites are along an elevation and rainfall gradient. We drove about 400 km, mostly in off-road conditions that were at times challenging even for our capable 4x4 vehicle. That said, one of the sites will need to be changed because the poor conditions of the roads means that it will take a lot longer than I had planned to get there and back. My collaborators at the Ministry of Environment and Climate Change suggested a site further to the east but that is accessible from the main highway. I didn’t get to see that site during this scoping trip because I was only there for a week, but I trust the judgement of my collaborators, so we will install the sensors at that site when I am back in Somaliland.
One of the sites was a dense evergreen Juniperus procera woodland with a grassy understory (see grid of photos) that had suffered extensive dieback. The location of most of the dead trees were to the west of the site and there were more live trees in the northern areas that offer an appropriate contrast for a more localized study of the causes of the diebacks. The soil sensors will be installed within the vicinity of both Juniperus stands, but the dendrometers will only be installed on the live trees. Between the dead and live stands is a patch of Dodonaea angustifolia on sandy soil and devoid of a woody canopy. This area will serve as a good mid-point for soil sensors to look at how the moisture and temperature profile differs from the other two. There were other woody species, notably Eucalyptus, that can serve as potential hosts for the dendrometers, in order to compare differences in growth between species.
All in all it was a fruitful trip that gave me good insight into the sites. I will return to Somaliland during the early summer, shortly after the Gu rains to install the sensor network and begin the data collection process.