Deathworld 1 by Harry Harrison

In a universe where planets are colonized and exploited, a professional gambler named Jason dinAlt finds himself on a perilous world where every living thing is hostile to human life. Tasked with helping the settlers of this deadly planet, Jason must navigate a landscape teeming with lethal flora and fauna, while uncovering the secrets behind the planet's aggressive nature. As he delves deeper into the mystery, he discovers that survival depends not only on his cunning and resourcefulness but also on understanding the intricate balance between the settlers and the planet's ecosystem.