The analyst specializing in militant groups added that these trends have been apparent for some time and they are only "becoming worse."
Many foreign fighters have become disillusioned with Daesh, which controlled large swathes of land in the Middle East and promised to create a full-fledged state at the height of its power. Aymenn Jawad al-Tamimi said that there are internal and external reasons pointing to the fact that the brutal group has become less attractive to foreign recruits.
"Conditions have deteriorated within the self-declared caliphate in terms of quality of life and salary payments," he explained. Those contemplating joining Daesh no longer believe that the group will provide an "all-inclusive benefits package" to its recruits.
The group which received half of its income from smuggling oil was once known as the richest terrorist organization in the world. It was forced to lower salaries when Russian and US-led coalitions focused on destroying the infrastructure underpinning its illicit energy trade.
"Of course there are some places where [Daesh] can regain territory or perhaps put more of a fight, … but the overall trend is still against it in terms of losing territory. That undermines the image that it wishes to project as a self-declared caliphate," he said.
Turkey's decision to push Daesh out of northern Syria has also affected the group's recruitment efforts.
"I think that as long as Daesh does not have border access with Turkey, then that's a huge problem in trying to get new waves of foreign fighters to come in. Now there is still of course the problem of other jihadi groups that recruit foreign fighters, but Daesh's recruitment has already sharply dropped off and is probably unlikely to recover," he said.
Aymenn Jawad al-Tamimi was referring to Operation Euphrates Shield, a large-scale military campaign which Ankara launched on 4 August to push Daesh out of cities and settlements located on Syria's border with Turkey.
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