▁veget ation ▁but ▁det ers ▁the ▁growth ▁of ▁future ▁veget ation . ▁D ug an ▁and ▁Hub b ard ▁found ▁that ▁the ▁gro omed ▁port ions ▁of ▁a ▁beach ▁experienced ▁significantly ▁lower ▁rates ▁of ▁plant ▁surv ival ▁and ▁reprodu ction ▁after ▁germ ination ▁than ▁the ▁ung room ed ▁sections ▁of ▁the ▁same ▁beach . ▁ ▁As ▁veget ation ▁abund ance ▁and ▁the ▁height ▁and ▁presence ▁of ▁d unes ▁and ▁hum mock s ▁decrease , ▁sand ▁transport ▁patterns ▁change ▁in ▁a ▁way ▁that ▁fur thers ▁the ▁extent ▁of ▁fl atten ed ▁top ography . ▁Hum mock s , ▁d unes , ▁and ▁veget ation ▁act ▁as ▁obst acles ▁that ▁slow ▁sand ▁movement ▁triggered ▁by ▁the ▁wind . ▁When ▁these ▁features ▁disappear , ▁the ▁formation ▁of ▁future ▁hum mock s ▁and ▁d unes ▁becomes ▁more ▁difficult ▁and ▁unlikely . ▁ ▁As ▁be aches ▁grow ▁fl atter ▁and ▁wider , ▁the ▁abund ance ▁and ▁divers ity ▁of ▁veget ation ▁decre ases ▁further ▁because ▁veget ation ▁requires ▁stable ▁sand ▁d unes ▁to ▁take ▁root ▁and ▁grow . ▁ ▁In ▁this ▁way , ▁mechanical ▁beach ▁clean ing ▁triggers ▁a ▁positive ▁feedback ▁loop ▁that ▁ex ac erb ates ▁the ▁fl atten ing ▁and ▁w iden ing ▁of ▁be aches ▁alongside ▁the ▁loss ▁of ▁veget ation ▁abund ance ▁and ▁divers ity . ▁Hal ting ▁mechanical ▁beach ▁clean ing ▁stops ▁this ▁cycle ▁and ▁can ▁re build ▁the ▁dam aged ▁top ography ▁and ▁lost ▁veget ation . ▁For ▁example , ▁D ug an ▁and ▁Hub b ard ▁observed ▁that ▁four ▁years ▁after