What Did the Romans Ever Do for Us? The Biodiversity Edition

When you think of the Roman Empire, biodiversity probably isn’t the first thing that comes to mind. Alongside roads, aqueducts, architecture, and law, the Romans introduced plants and animals across Europe through deliberate species transfers and expansive trade networks, transforming the continent’s natural environment.

This blog explores how their influence on biodiversity in the western empire continues to shape the continent’s ecological landscape even today. Some of the species introduced by the Romans went on to become invasive, and with invasive species posing an ever-growing threat to ecosystems today, technologies like Gentian's are revolutionising how we detect and respond to these challenges.

Trade Networks 

The Romans' vast trade networks led to unprecedented wildlife movement across the empire. Ships carried not just olive oil and wine, but soil, seeds, animals and stowaway insects. Species were both introduced to new regions and extracted from their native habitats for food, entertainment, and luxury goods, often depleting source populations.

Map of the Roman Trade Network, 180 AD (Credit: Adhavoc)

Through this 80,000 km trade network, the roman road network fragmented habitats but created new corridors for plant dispersal. Cities became novel ecosystems, attracting adaptable species like pigeons whilst pushing out large predators.

The Movement of Exotic Species

The Empire’s appetite for exotic animal spectacles had a devastating ecological impact. Amphitheatre games, which demanded large numbers of wild animals, contributed to the decline and even extinction of several species. The North African elephant (Loxodonta africana pharaoensis), for example, was driven to extinction through a combination of warfare and public entertainment. Events such as Emperor Titus’s inaugural games at the Colosseum, which saw 9,000 animals killed over 100 days, exemplify this destruction. This one-way extraction of wildlife from source regions caused sharp population declines, notably affecting species such as the African wild ass and the addax antelope in areas like Tunisia.

However, some species were moved for practical purposes. As skilled cultivators and animal breeders, the Romans transported useful species wherever they went. 

Wild Animals

Though often associated with British countryside and Easter celebrations, the European rabbit (Oryctolagus cuniculus) was first introduced to the British Isles by the Romans. Native to the Iberian Peninsula, rabbits were brought northward as a source of food and fur. At the time, their presence was relatively controlled. But over the centuries, populations exploded, and they’re now one of the most widespread and ecologically disruptive species in the UK.

European rabbit, Oryctolagus cuniculus sitting in a meadow.

Other examples include the egyptian mongoose that was introduced to Iberia for pest control, the fallow deer from the Eastern Mediterranean that were kept in enclosures for hunting. Pheasants from Asia became naturalised, while peacocks and guinea fowl served as ornamental birds. Romans also raised the edible dormouse for food and introduced the "Roman snail" to Britain, where it still lives today. 

Domestic Animals and Rodents

The Romans spread improved breeds of farm animals across their provinces. Their most significant introduction was the domestic cat (Felis catus), which came from Egypt and the Near East as both pest controllers and pets. Following the 43 AD conquest, archaeological evidence shows that house cats established themselves in Britain. 

The Romans conducted widespread deforestation across Western Europe and North Africa for agriculture, construction, and fuel. This led to habitat loss for forest species, soil erosion, and in North Africa, contributed to desertification. However, new open landscapes also created habitats for different species like field birds and rodents. The black rat (Rattus rattus) arrived on Roman ships during two waves of colonisation. Archaeological evidence from Roman London and York shows their early presence, though they spread more widely in medieval times. 

Plant Species

In Britain alone, at the empire's northwestern frontier, the Romans introduced at least 50 new plant foods, transforming local agriculture. Their intensive farming methods transformed ecosystems through large-scale crop cultivation, irrigation systems, and wetland drainage. Whilst this reduced native plant diversity, it also spread new species, including Mediterranean weeds that became permanent additions to local flora.

Fruit and Nut Trees

The Romans didn’t just build roads—they brought fruit with them. As they expanded into northern Europe, they introduced a variety of Mediterranean fruit and nut trees to new regions. In Britain, Roman settlers planted apple, cherry, plum, pear, and damson trees, along with sweet chestnut and walnut for their nuts. Remarkably, some ancient chestnut groves established during Roman times still survive in parts of southern England and France. Mulberry trees were also cultivated, valued not only for their fruit but for their potential use in silk production.

Vegetables and Herbs

The Romans introduced numerous vegetables to Western Europe, including asparagus, carrots, celery, cucumbers, leeks, onions, garlic, and cabbage. They also brought herbs like fennel, coriander, rosemary, and bay laurel. Some introduced species like ground elder (Aegopodium podagraria) and  alexanders (Smyrnium olusatrum) later naturalised and now grow wild in Britain.

Field of aegopodium podagraria, commonly referred to as ground elder, grassland, bishop, and gout.

Invasive Species: A Growing Problem

The Roman Empire’s vast trade networks were unprecedented for their time. They transported goods—and inadvertently species—across continents. Some species adapted and integrated, while others turned invasive in ecosystems that lacked natural predators or controls. Many invasive species we struggle with today have their roots in ancient trade and colonisation. 

The damage caused by invasive species is multifaceted. They often outcompete native species for resources, alter habitat structures, and contribute to soil and water degradation. In ecosystems like peatlands—fragile, carbon-rich environments essential for climate regulation—the presence of invasive plants can be particularly destructive, drying out the land and suppressing native regeneration.

How Gentian is Revolutionising Invasive Species Detection

This is where Gentian steps in with an innovative, AI-powered approach to ecosystem management. Building on the lessons of the past and harnessing cutting-edge technology, Gentian offers a smarter, faster, and more cost-effective way to detect and control invasive species. By integrating Geographic Information Systems (GIS), remote sensing, and machine learning, Gentian is reshaping how we manage biodiversity threats today.

The Roman introductions above shaped modern European landscapes. Many species, like sweet chestnut trees, rabbits, and pheasants, are now so established they seem native to the areas they were introduced to. The Romans' movement of species marked Europe's first major biological mixing event, arguably increasing biodiversity but also introducing non-native species challenges.

Today, invasive species remain a complex and costly legacy of centuries-old interactions between people and nature. But with AI, satellite imaging, and data science, we can address those challenges with clarity and efficiency. Gentian is leading the charge in this smarter approach to biodiversity management, helping us protect ecosystems, meet regulatory demands, and restore landscapes once lost.