I recently noted Russia's use of civilian assets to enable their operations in Syria and mentioned China:
Which is why I don't assume, as so many still do today, that China--with a massive civilian shipping fleet--can't invade Taiwan just because China doesn't have a large force of dedicated amphibious warfare ships.
China also has a tiny marine force (just 10,000 in 2012), which complements the lack of dedicated amphibious shipping as an argument against China's capacity to invade Taiwan.
But soldiers can do that job. If China is willing to run the risk that we will intervene quickly enough and if they are willing to endure the casualties, China can throw a force across the strait.
You might want to note that many of our amphibious operations in the Pacific during World War II were carried about by the Army and all of the European theater invasions were by Army troops (albeit with specialized equipment, I admit, but that made the invasions more effective rather than being required). So China can invade Taiwan with their ground and naval assets even if they don't look like our very unique capabilities (including the scale of our capabilities).
Here's another clue that China would not rely on their marines for an invasion:
Days after China passed a new law that for the first time permits its military to venture overseas on counter-terror operations, its marines began exercises in the western deserts of Xinjiang, more than 2,000 kilometers from the nearest ocean.
The continuing drills are an indication, analysts say, that the marines, who have traditionally trained for amphibious assault missions, are being honed into an elite force capable of deploying on land far from mainland China.
China's small marine force could certainly spearhead parts of an invasion of Taiwan, but army units on conscripted civilian ships would have to carry out the bulk of the sea portion of the invasion (add in airborne and airlifted assets, of course).
And the lack of need for China's small marine force to invade Taiwan is why China is training this force for overseas contingencies.
Army troops can be put on ships for a short sail across the Taiwan Strait. Marines are more suited to sitting on amphibious warfare ships for months on end preparing for a crisis that China needs reliable troops to respond.
If China needed these troops for a Taiwan scenario, China wouldn't be earmarking them for distant operations.