No, @_ is an alias to the sub's arguments. That's how things like chomp work:

sub my_chomp {
   $_[0] =~ s/\r?\n\z//sm;
}

my $var = "foo\n";
my_chomp $var;
print "[[$foo]]\n";
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perlsub says:

The array @_ is a local array, but its elements are aliases for the actual scalar parameters.