Aquidauana, Brazil — Bigger than Portugal and Spain combined and perhaps the world's largest virgin territory outside the Amazon jungle, the Pantanal is a naturalist's dream. Stretching 150,000 square miles over western Brazil, this majestic marshland teems with tens of thousands of species of animal life and the rarest of tropical flora.
''It's a mosaic of paradise,'' says Wilson Barbosa Martins, governor-elect of the state of Mato Grosso do Sul. He has trekked the Pantanal since his youth.
But paradise has lately become a treacherous place, ruled not by the turn of seasons but by the turn of fat profits and the barrel of the outlaw gun.
Eluser Albuquerque became the first casualty of an undeclared land war between poachers and wealthy farmers in this vast part of the continent when he was struck by a bullet from a poacher's rifle in January. The ''war'' is terrorizing civilians and has embroiled three South American republics.
The aggressors have no cause celebre. They are some 3,000 heavily armed hunters who command a small fleet of boats and bush planes. Dug in all over the intractable frontier of Bolivia, Brazil, and Paraguay, they are after alligator, otter, or any other game with pelts of commercial value - and they will shoot anything in their way.
The poachers killed an estimated 2 million alligators last year, selling their hides to a network of foreign tanners and tailors for a neat $26 million. If the killing continues at this rate, naturalists say, it will not only endanger the Pantanal alligator but also all other wildlife in this wetland.
''This is a national emergency,'' explodes Cleone Gomes de Arruda, jabbing his index finger in the air. ''Bolivians and Paraguayans are invading our nation.''
Mr. Gomes is the accountant on a wealthy estate in the town of Aquidauana, Mato Grosso do Sul, at the mouth of the Pantanal. Not far from here, in late January, farmers spotted a band of eight armed men slipping into the swamps.
The military police dispatched seven men, including Mr. Albuquerque into the Pantanal, which is covered in this rainy season by a swollen web of rivers and streams. Wading for an entire day in waist-deep water and 110 degree heat, the police surprised the contrabanidistas at their camouflaged campsite. Shots were exchanged. Albuquerque was hit and the poachers got away, abandoning their camp - which was littered with rations, Japanese lanterns, imported cigarettes, ammunition, and more than 1,500 alligators.
This was only one incident in the Pantanal, where the slaughter goes on daily. Aquidauana military police Lt. Carlos Enrique Silva says eight men, in a few hours, can kill a minimum of 200 alligators. At night, lanterns are used to mesmerize the alligators, whose eyes shine deep red in the lamplight. The hunters simply crack the dazzled creature over the head or place a point-blank . 22 round between the eyes.
The hunters - Paraguayans, Bolivians, and Brazilians - reportedly are financed by a ''mafia'' of hide traffickers seated in the river port town of Corumba. According to Norman E. Hanson, a Brazilian environmental official, they are flown into Brazil by small propeller planes and enter the Pantanal by night in chalanas, the nimble swamp canoes of the region.
Next to the poachers, who are armed with automatic rifles and 9-mm pistols and transported by swift Cessna planes, the military police are sorely outclassed. They have no planes or boats, and three companies totaling no more than 60 men try to keep the peace in the entire Pantanal.
Arrests are rare, and every encounter with poachers brings the risk of violence. ''Poachers shoot first and talk later,'' said Lieutenant Silva of the Aquidauana patrol.
Nor are civilians safe from the hunters. ''They invade your farm, kill your cattle for meat, and come into your kitchen to rob your table salt for curing the alligator hides,'' said Cleone Gomes of the Gunandy Fazenda.
Police are also frustrated that their prisoners are routinely let off with a light fine because poaching is not a jailable offense.
The ecology of the Pantanal is already endangered, according to environmentalists. The slaughter of alligators has resulted in the proliferation of their staple diet, piranha, which last year mutilated hundreds of cattle and nearly drove one small dairyman into bankruptcy. ''If this isn't stopped, in three years the Pantanal will be destroyed,'' says Dr. Asturio Ferreira dos Santos of the Committee to Defend the Pantanal.
Finally, after a shootout last week, Brazilian President Joao Baptista de Oliveira Figueiredo ordered the federal police and regular Brazilian Army units into the Pantanal to combat this ''invasion of national territory.''
Yet, stepped-up patrols are not likely to halt the poaching. Much will depend on cooperation from Bolivia and Paraguay, which have so far declined signing accords by the United Nations Committee to Control Commerce in Endangered Wildlife.
The glitter of fast profits attracts any number of residents in this economically depressed frontier region. Bush pilots can earn up to $1,500 a day flying hides out of the Pantanal, and hunters make from $8 to $13 per alligator skin.
A seasoned resident of on Brazil's border said, ''Every unemployed fisherman is an alligator poacher in the Pantanal.''