Argan trees are crucial to the economy of Morocco, a lower-middle income country. These trees bear fruits whose seeds are pressed to produce argan oil, a valuable commodity that brings $6.5 million in exports.
Now, a new study has shed light on the important role that tree-climbing goats in Morocco play in the propagation of Argan trees. It turns out that these acrobatic animals disperse the seeds of these trees when they spit the nuts out.
Seed dispersal transports seeds away from the mother plant. Seeds that just fall under the parent plant may not get enough water, sun, or nutrients from the soil. Seed dispersal thus improves the odds of plants to survive and helps them spread out and grow in new places.
In arid areas of Morocco, where the argan trees grow, farmers encourage the goats to climb and eat on the trees to get the seeds that are eventually processed into argan oil.
Domesticated goats that live in grassy and temperate climate do not climb trees because their food is often readily available. In hot regions with patchy grasses, though, the animals climb trees for sustenance.
The seeds that the goats swallow and poop out would later sprout as trees, but this may not apply to sizable seeds such as that of the argan.
Researchers of a new study said that goats do not often defecate large seeds, which made them skeptical that the argan nuts, which are about the size of the acorn, went through the same route of smaller seeds.
Ruminants And Seed Dispersal
Goats are ruminants, which means that they rechew their food after these are left in a specialized compartment of the stomach to ferment.
The researchers decided to verify if goats regurgitated the seeds of the argan fruit during rumination, a process they suspected to be a potential dispersal mechanism for the large seeds.
For their research, they fed Spanish domestic goats fruits of varying sizes. They did not have access to the argan fruit trees, but in their study, they observed that the largest seeds, which are still smaller than an argan nut, were most likely to be spat out by the animals. The smaller seeds often end up in the feces. It sometimes takes up to six days for the goats in the study to spit out swallowed seeds.
The researchers then test the viability of the regurgitated seeds and discovered that more than 70 percent can still grow, which suggests that the goats spitting out seeds could actually be helping scatter the seeds that they eat.
The researchers added that since the seeds remain in the goat's stomach for hours or days, they potentially release the seeds very far from the mother plant, which can benefit the Argan trees.
"For plants there are well-known reproductive benefits associated with dispersing their seeds far from the maternal parent, including a greater probability of seed and seedling survival," study researcher Jose Fedriani, from the University of Lisbon in Portugal, and colleagues wrote in their study, which was published in the journal Frontiers in Ecology and the Environment.