I found these numbers reading through wikipedia, but none of the linked sources that I looked through have much information on the transition period when Chiang Kai-shek’s government and troops left mainland and settled in Taiwan. I know that mass migrations typically put a strain on the regions being migrated too, so my question is whether this was the case in Taiwan? These could be technical, like a shortage of housing or food resources, or political, like resentment towards the newcomers and increased social tensions.
I previously wrote here about the resentment of Taiwanese people towards mainlanders, so on this post I will write a bit about other consequences of the influx of mainlanders. This won't be a super long answer since I think it's fairly straightforward and easy to be brief about.
During November of 1948, more than 31,000 mainland refugees per week fled to Taiwan. This increased to around 5,000 refugees per day by the beginning of 1949. Most of these refugees were government officials and military figures, but not all, as my previous writing on the topic above discusses. This evacuation of the mainland continued through 1950. I want to say that the administration of Taiwan by the Guomindang after 1945 was already pretty incompetent and it culminated in the 228 Incident in 1947. Among the troubles prior to this influx of refugees were job loss and inflation. So Taiwan was already in a bad state, under martial law, before the mainlanders even evacuated to the island. As this refugee crisis unfolded, these problems were severely excaberated. Crime increased, as did unemployment, and food and housing shortages. Rampant inflation sparked by the mainland's civil war also was very damaging to Taiwan; the island was full of what was essentially useless money. There was mass panic buying of foods, and the government had to crack down on it. As the Republic of China and Taiwan became more synonymous, the government stopped exporting food and resources from Taiwan to the mainland, which helped to relieve the food shortages and inflation. Basically, the refugee crisis caused major economic issues in Taiwan, in addition to the very widespread political discontent I discussed before.
Source: "Between Assimilation and Independence: Taiwanese Political Aspirations Under Nationalist Chinese Rule, 1945-1948" by Steven Phillips in Taiwan, A New History edited by Murray Rubinstein