Into the Amazon: Biological Exploration of the World's Most Biodiverse Region

The Amazon basin — covering approximately 7 million square kilometres across nine South American countries — is the most biodiverse region on Earth. It contains an estimated 10% of all species on the planet: approximately 40,000 plant species, 1,300 bird species, 3,000 types of fish, and millions of invertebrate species, the majority of which have never been formally described by science. Despite centuries of natural history collecting, the Amazon continues to yield hundreds of new species annually from this vast and still inadequately surveyed biome.

The Challenge of Amazon Survey

Conducting biological surveys in the Amazon is extraordinarily challenging. Much of the basin is accessible only by river, and the river network still leaves vast areas of upland forest accessible only by helicopter or on foot. The climate — hot, humid, and subject to intense rainfall — degrades equipment, damages specimens, and makes fieldwork physically demanding. Many areas are remote from medical care, creating real health risks from tropical diseases, venomous animals, and accidents in the field.

New Species Discovery

Scientific expeditions to the Amazon describe hundreds of species new to science each year — including recent new species of primates, large catfish, and many hundreds of invertebrate and plant species. The process of describing a new species requires collecting physical specimens, comparing them with existing museum collections, and publishing a formal scientific description. This process can take years — meaning that species collected on an expedition may not be formally described for a decade or more after collection. The backlog of collected but undescribed material in natural history museums worldwide is estimated at tens of millions of specimens.

Canopy Science

The forest canopy — 20-40 metres above the ground — is among the most species-rich habitats in the Amazon and among the hardest to access. Canopy cranes, rope systems, and now drones are giving researchers access to this sky-world where an estimated 40-50% of Amazon biodiversity resides. Canopy surveys consistently find species not recorded from ground-level surveys — specialised insects, reptiles, birds, and plants that spend their entire lives above the reach of traditional collecting methods.

Tributary Science — Rivers as Ecological Boundaries

The Amazon basin's 1,100+ tributaries are not merely waterways — they are biogeographic barriers that have driven the evolution of some of the most extraordinary biodiversity on Earth. Many Amazonian bird, primate, and reptile species show sharp distributional boundaries along major river channels: populations on opposite banks of the same river may be so genetically diverged after millions of years of isolation that they constitute distinct species. The "river barriers hypothesis" — proposed in the context of Amazonian biogeography — suggests that large rivers prevent the gene flow between populations on opposite banks, leading to independent evolutionary trajectories and ultimately speciation. This hypothesis predicts that biodiversity should be highest where the most rivers converge (the lower Amazon, where multiple tributaries flow into the main stem) — a prediction broadly confirmed by species richness maps. Field expeditions to remote Amazonian tributaries continue to discover new species at high rates: a single multidisciplinary expedition to the Serra do Divisor region in 2014 documented 36 fish species new to science, 7 new amphibian species, and numerous new invertebrates.

The participation of local and indigenous community members as field assistants, guides, and co-investigators in Amazonian biodiversity surveys — beyond providing essential logistical support — contributes ecological knowledge, language skills for voucher data collection, and community engagement that increases the long-term conservation relevance and impact of expedition findings in ways that externally-led science alone rarely achieves.

Remote Sensing Transforms Amazonian Science

The Amazon basin — 5.5 million square kilometres of continuous tropical forest — is too large and too remote for comprehensive ground-based scientific survey. Remote sensing has transformed our understanding of Amazon ecology by allowing simultaneous measurement of vegetation structure, species composition, forest disturbance, and ecosystem function across the entire basin. Lidar (Light Detection and Ranging) — which bounces laser pulses off forest canopies to reconstruct three-dimensional vegetation structure — has enabled the first basin-wide mapping of Amazonian tree height, canopy density, and above-ground biomass, revealing systematic gradients in forest structure from the wet western Amazon (tall, dense forests with the highest biomass) to the drier, more seasonal eastern Amazon (shorter, more open forests with lower biomass). Hyperspectral imaging — which measures light reflectance at hundreds of wavelengths simultaneously — can distinguish hundreds of tree species by their spectral "fingerprints," making it possible to map tree species diversity and community composition across tens of thousands of hectares from airborne instruments.