Pilibhit Tiger Reserve, located in the northern Indian state of Uttar Pradesh, is renowned for its rich biodiversity. Here are some key aspects of the biodiversity found in this reserve:

1. Mammals: Pilibhit Tiger Reserve is home to a diverse range of mammalian species. Apart from the Bengal tiger, it houses animals like Indian elephants, leopards, cheetahs, sloth bears, dholes (Indian wild dogs) and several species of deer, including spotted deer, barking deer and sambar. It's also an important habitat for swamp deer (barasingha) and the elusive fishing cat.     

2. Birds: The reserve is a haven for birdwatchers with over 300 avian species. It's particularly known for harboring the Bengal florican, a critically endangered bird species. You can also spot a variety of waterfowl in its wetlands, including sarus cranes, white-crowned penduline-tits and great slaty woodpeckers.

3. Reptiles: The reserve is home to several reptile species, including pythons, cobras, vipers and Indian rock pythons. It's an important habitat for the critically endangered gharial, a type of crocodile.

4. Amphibians: Pilibhit Tiger Reserve supports a range of amphibian species, contributing to the overall biodiversity. This includes different types of frogs and toads.

5. Invertebrates: Invertebrates, such as various insects and spiders, play a vital role in the ecosystem. They provide food for many of the reserve's bird species and also contribute to pollination. 

6. Plants: The reserve is known for its lush vegetation, featuring diverse types of forests, grasslands and wetlands. You can find a wide variety of plant species, including sal, teak, bamboo and several aquatic plants.

7. Aquatic Life: The numerous rivers, streams and wetlands in Pilibhit Tiger Reserve support various aquatic life forms. These include different species of fish, turtles and other water-dependent organisms. 

8. Flora and Fauna Interaction: The interaction between the diverse flora and fauna in the reserve sustains the ecosystem. For instance, the presence of various plant species provides food, shelter and breeding grounds for the wide array of animal species.

The biodiversity of Pilibhit Tiger Reserve makes it a significant conservation area, and its diverse ecosystems play a critical role in supporting wildlife populations. It's not just a sanctuary for charismatic megafauna like tigers and elephants, but also a treasure trove of less-recognized species, making it a prime location for both wildlife enthusiasts and conservationists.