<p>Technologies for biodiversity assessment are crucial for addressing the global biodiversity crisis, and ecological monitoring is seeing increased use of robotics. Interdisciplinary working will be critical in finding the best robotic solutions for monitoring. As a team of ecologists and robotics scientists, we conducted a systematic literature search for robots in ecological monitoring and reviewed their ecological monitoring applications and technological capabilities, such as level of autonomy, operation time and adaptability. We identified 67 relevant papers reporting individual robots or robot teams. The number of robots developed for ecological monitoring has grown rapidly in recent years, targeting a wide range of taxa or communities. Image or video capture were the most common types of monitoring although telemetry, acoustics, echolocation, radar and fluorescence sensors have been adopted. We identified that further use of acoustic monitoring and eDNA collection could provide enhanced robotic monitoring opportunities. Technological capabilities are more advanced for robots built for marine environments or lacustrine freshwater ecosystems than for terrestrial or lotic freshwater ecosystems. This likely reflects the longer history of marine robot development, lack of alternative surveying approaches at depth or far from infrastructure, and the energy rich environment and neutral buoyancy that oceans provide. Nevertheless, there are opportunities for robots to enhance terrestrial ecological monitoring, particularly where teams of robots can be developed. Recent developments in autonomous navigation systems, visual sensors and energy management offer potential solutions that could be integrated into robots for ecology.</p>