Illustration: Liu Rui/GT

With the eye-catching Sunflower Student Movement heating up the relationship between Taiwan and the mainland, we've seen a lot of political analysis on the cross-Straits relationship, but little economic insight.

In 2012, Taiwan's ratio of dependence on trade from outside the island reached 112.59 percent, which indicates that the external market is of considerable importance to Taiwan.

Yet the global financial crisis decreased demand for goods in most developed economies. The Chinese mainland, one of the biggest and most promising markets, is like a giant magnet. Obviously, Taiwan is particularly drawn to this market.

In 2003, Taiwan gained a net trade surplus of $24.396 billion with the mainland. Since 2003, cross-Straits merchandise trade has sped up and its net trade surplus has increased with an average annual growth rate of over 10 percent.

Although affected by the global financial crisis, Taiwan's commodity exports to the mainland increased by an average $8 billion each year after 2010 when the cross-Straits Economic Cooperation Framework Agreement, a de facto free trade deal, was signed. The mainland has now become Taiwan's largest export market.

Compared with cross-Straits trade, mutual investment between Taiwan and mainland is small. In 2011, the mainland's outward direct investment in Taiwan was $11.08 million, and its stock was only $29.35 million, accounting for 0.05 percent of Taiwan's total received external direct investment.

One reason is the mainland's comparatively short history of outward investment and its developing policies of seeking natural resources in raw material-abundant countries.

Another more important reason may come from strict cross-Straits constraints on mutual inward investment, especially investment on service industry.

The Cross-Strait Service Trade Agreement (CSSTA) between Taiwan and the mainland, signed on June 21, 2013, seems likely to herald a big change in cross-Straits service trade relations and promote further openness in service industries. According to the text of the CSSTA, the mainland will open 80 service sectors to Taiwan, while Taiwan will open 64 sectors to the mainland.

This agreement has been greatly debated and has led to massive protests in Taipei since March 18. But from an economic perspective, Taiwan in fact gains a preferential ticket to access the mainland's huge service market with a remarkable first-mover advantage.

Cross-Straits tourism has boomed since 2009. There were 5.16 million Taiwanese traveling to the mainland at the end of 2013.

Some 2.85 million mainlanders traveled to Taiwan in the same period. This frequent and substantial mobility of individuals sparks a great demand and opportunities for mutual service trade and investment.

A key point is that cross-Straits trade, investment and individual mobility are not strictly separated. If one channel is blocked, the other channels will make up and offset negative effects to a certain degree.

In the case of the cross-Straits economic relationship, the existing high cross-Straits trade volumes and booming tourism have revealed both sides' mutual real demands on the other's goods and services.

If Taiwan shuts the door to cross-Straits service investment, more demand will be fulfilled through trade, resulting in Taiwan's deeper trade dependence on the mainland market. It would not only run against Taiwan's policy of greater economic independence from the mainland, but also increase its economic risk with serious imbalance between their mutual trade and investment.

Also, trade and investment transfer from one economy to another could happen. If the CSSTA falls into abeyance, South Korea and Singapore, strong competitors with the island of Taiwan, will be motivated to compete to be the mainland's service partner.

Also, Chinese President Xi Jinping's 2014 visit to Europe brought about a joint announcement on developing a comprehensive strategic partnership with the EU. A Sino-EU free trade agreement, which had been under discussion for at least a decade, will be under greater consideration.

Therefore, the cross-Straits economic relationship is already tight and Taiwan's economy is greatly integrated into the mainland's huge economic system.

Like it or not, no one in Taiwan can really deny the great importance of the mainland to the island's economy.

The author is a visiting research fellow of New Zealand Contemporary China Research Centre, Victoria University of Wellington and PhD candidate in the School of International Business at the Southwestern University of Finance and Economics. opinion@globaltimes.com.cn