Jezzine, Lebanon - The mayor of Jezzine, a Maronite and Greek Catholic town perched upon the pine-covered hills of southern Lebanon, is voicing an increasingly common fear among the tiny country's ancient Christian community: that they are under threat. "I'm fighting to keep Christians in Jezzine," said Khalil Harfouche, gesturing at the rolling green hills that neatly recede into the distance.

Anxiety among Christians over their declining proportion in the country has simmered for decades, but the unprecedented Syrian refugee influx has brought it to a boiling point.

"The number of Muslims is increasing more and more, and by expanding towards Christian regions, they [the Christians] will consider that there's no room for them any more," he told Al Jazeera.

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This month, the UN refugee agency (UNHCR) announced that there were officially one million Syrian refugees in Lebanon. The unofficial number is estimated to be much higher - around 1.5 million - meaning a quarter of Lebanon's population is now made up of Syrians, the overwhelming majority of whom are Sunni Muslims.

For the Maronite Church, the demographic shift could threaten the country's unique formula of religious co-existence. "Everybody is worried because they don't want this formula to fail," said Archbishop Paul Sayah at his office overlooking the Mediterranean Sea in Bkirki, the seat of the Maronite Patriarchate.

"If it does, well, the alternative is that the religions can't live together, and if they can't live together, they will fight each other."

It's going to be a way to have the Christians leaving the region, and we won't allow that. - Khalil Harfouche, mayor of Jezzine

Prior to the refugee influx, Christians were estimated to make up around 40 percent of the population. That's down from the 54 percent recorded in a dubious national census in 1932 that formed the basis of independent Lebanon's 1943 National Pact - a document that gave Christians more political power than Muslims, partly by stipulating that they should have six seats in Parliament for every five given to Muslims.

This imbalance - previously a major source of unrest - was redressed in the Taif Accord, the long-awaited peace agreement that ended the Lebanese Civil War and instated a 50:50 political power-sharing system between Muslims and Christians that continues to this day. But the division of power is still off the 60:40 Muslim/Christian demographic reality on the ground.

Fears over the effects of shifting demographics can be seen in the country's treatment of its Palestinian population. There has been deep-rooted resistance to granting Lebanese citizenship or even full civil rights to more than 400,000 impoverished, mainly Muslim Palestinian refugees, although many Christian Palestinians were naturalised in the 1990s. This attitude persists to this day, with Foreign Minister Jebran Bassil recently saying that "naturalisation [of the Palestinians] will cause damage to the demography" of Lebanon.

With no end in sight for the Syrian civil war, some worry that part of the rapidly growing refugee population could become permanent and displace the country's Christians, laying the foundation for potential future adjustments to the political system.

Harfouche, Jezzine's mayor, is also the new head of a municipality union that is 97 percent Christian - of various sects, but mainly Maronite - and covers nearly the entire wider district of Jezzine. He was at the forefront of efforts last year to stop the sale of a school in Lebaa village in his district to an Islamic non-governmental organisation for a Syrian refugee project.

"They wanted to put 3,000 or 4,000 people there," he said, shaking his head. "It would have been a mini-camp. We don't want to replicate the same [Palestinian] problem... It's going to be a way to have the Christians leaving the region, and we won't allow that."

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On top of working to limit the number of Syrian refugees in his district, Harfouche is bringing in new zoning restrictions in the corner of Lebanon he controls. The idea is to preserve the demographic status quo by making construction more difficult, thus hindering local Christians from being able to sell their land.

"The changing demographic balance is one of the biggest threats to the Christian community at the moment," said Harfouche. Before his new measures came in, he said there "was a trend of local land being bought by Muslims".

"I can guess that more than 100,000sqr m used to be sold on a yearly basis," he added. "I don't have exact numbers… but what I am sure of is that currently it's almost nil."

This country is for everyone. You cannot tell me where to live and where not to live. - Mohamad Jaafil, CEO of Saida Real Estate

According to Pierre Atallah, vice president of the group Lebanese Land - Our Land Movement, 132 million sqr m of Christian-owned land have either been sold to, or appropriated by Muslims in the last few years - about one percent of Lebanon's 10,400-square-kilometre total area.

"Christians still own more than half of Lebanese territory," added Atallah, whose organisation works to prevent Christians from selling land to Muslims. "It is retreating from the glorious days, however, when they used to own around 70 percent."

Harfouche's Urban Master Plan aims to tackle this by using building restrictions to deter buyers. "Each zone has its own rules with regards to the percentage of construction allowed. Whenever we think there is a threat of land sale to people outside the region… we decrease the percentage," he said.

"The region" is a thinly veiled reference not just to Jezzine, but to the local Christian community in general. Those "outside the region" include the Druze to the north and the Muslims living to the east, south and west. This western area refers largely to the coastal area around Saida, Lebanon's third-largest city where nearly three-quarters of the residents are Sunni, according to 2005 voting data.

A lawyer who specialises in real estate said the Urban Master Plan was entirely within the mayor's rights. "It is the prerogative of the mayor to decide the zoning restrictions… he knows what is in the best interest of his constituents."

Of course, sectarian or racist-inspired policies are illegal under Lebanese law, but the lawyer - who asked not to be named due to the sensitivity of the issue - said that as long as there was a legal justification for the restrictions, it was legitimate. "The applicant can always go to the governorate if they are not happy," the lawyer added.

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Land is a factor in measuring the influence and power of any community, Atallah said, citing an awareness among Christians that land "is one of the major factors for our presence in Lebanon. Due to this public awareness… now someone who wants to sell land, he counts to 10 because everyone will start to say, ‘Traitor, shame on you.'"

The sectarian-driven policies are already having a tangible effect.

"A client called me from Dubai and he was nearly crying," said Mohamad Jaafil, CEO of Saida Real Estate. "The new mayor of a place next to Jezzine called Homsiyeh had dropped the percentage [of land upon which people can build] from [between] 30-60 percent to [between] 10-20. He had already bought the land at a high cost… now 50 percent of the price of the land will drop."

In another case, Jaafil's wife's cousin, who is Muslim, tried to get a document from the mayor of Qaytouli to finalise the ownership transfer of a piece of land bought 15 years ago. "The mayor of the village, which is also right by Jezzine, told him straight out, ‘No land transfers or sales of land to Muslims on my time.'"

Jaafil blames politics, not religion, for the new, stricter measures, but is offended by them regardless. "This country is for everyone. You cannot tell me where to live and where not to live. I am a Lebanese citizen and I have a right to live on every spot of Lebanon."