Plant commentary & sustainability analysis
Plants will always be an integral part of the human diet and so agriculture will be a part of human life and economic botany for many years to come. However, the phase of discovery and redistribution appears to be largely behind us. The countries of the world are now closely interconnected and interdependent. Like the colonialism before it, globalization has provided material well-being for many but also generated a less fortunate underclass. But the price has been a uniformity of lifestyle and diminishing mystery of the exotic as we join the global village. It is possible that there may still be miracle medicines, new foods, and exquisite ornamental plants to be discovered in the Amazon jungle, Asian rainforests, and other remote regions of the world – but this possibility is diminishing fast.
With the benefit of hindsight, we can judge the past as a time of impulsive greed and intrepid adventurers with a winner-take-all philosophy. Though human nature may not change, the nature of the world is now completely different. Though the past may be perceived negatively, we now have an opportunity to pause, reflect on what has happened, and plan for a more equitable and sustainable future.
The most marked ways in which humans have impacted on plants are through changes to their biology, geography, and modes of cultivation.
Though some changes in modes of cultivation may occur in the future the basic pattern and composition of plants devoted to the major modes of cultivation – agriculture, horticultural crops, forestry, and ornamental horticulture – seem unlikely to change dramatically as the phase of international exchange and re-distribution of food plants has now passed. It is likely that for some time the logging of world rainforests will continue for some time in regions where human need overrides environmental concerns, but if human needs can be met then perhaps reafforestation will occur in tropical and subtropical regions as has occurred in the northern hemisphere.
Much of the plant future will probably be marked by the influence of advanced scientific techniques. Humans have altered the biological make-up of many of their cultivated plants such that the cultivated landscapes we drive through now consist of anthropogenic plants or cultigens. This process of biological change began with the (probably unconscious) process of plant selection that was part of the Neolithic Agricultural Revolution but it gathered momentum in the 20th century with the application of genetics to deliberate plant breeding. Today biological manipulation has taken a further step into genetic engineering (from the 1980s) which has generated its own suite of problems: concerns about their effect on health, labelling in shops, the moral and other uncertainties related to genetic tampering such as the consequence then why do we es of genetic pollution (the spread of ‘man-made’ genes into natural populations), problems concerning the ethics of intellectual property and royalties, genetic piracy, creation of frivolous genetic monsters, and so on. This deluge of misgivings is countered by the possibility of crops that have the potential for far greater yields, disease-resistance, and the relief of global poverty.
We need to monitor the geographic and temporal history of plant globalization, its costs and benefits, including the risks associated with different plant and trade route pathways. This process is only just beginning (see Dodd for Australia, and SESYNC for America where over 2.5 billion plants were imported into the United States in 2009, for a brief outline of import-export restrictions in Britain and the EU see RHS).
We use cultivated plants to nurture both the body (as food, medicine, and materials) and the soul (through their spiritual, intellectual, and ornamental values). To derive maximum benefit from them, we have moved them around the world using the most efficient transport systems available at any particular time and place. We have also changed them physically, by using the most effective scientific means at our disposal – passing historically from selection (from around 12,000 BCE), breeding combined with selection (well established by 1930s), and genetic engineering (1980s onwards). In this sense, most horticultural crops and the plants of agriculture and forestry are anthropogenic, less so those of ornamental horticulture.
The human domestication of crops from wild plants has been well studied although in many cases the selection process has taken so long that wild ancestors are unknown. The distribution of ornamental plants is more complex and yet to be given appropriate attention.
Since the Bronze Age human plant use has been most evident outside city walls in the mass-production of food, the total space that has been dedicated to food increasing as the human population has increased from about 10 million in 10,000 BCE, to 350 million in 1500 CE, and 7.5 billion today. wild nature has been progressively tamed into cultural landscape.
The human dispersal of plants gathered momentum when agrarian communities turned into urban city-states that engaged in long-distance exploration, expansion, and trade. Bronze Age civilizations of the East and West exchanged luxury and other goods along the Silk Road, this route being most active during the period of the Roman Empire and Han Dynasty before the strategic, economic, and scientific expansion of Europe in the Age of Discovery. Western maritime trade moved out of the Mediterranean to establish an Atlantic economy while other trade routes reached across the Indian Ocean to the Pacific Ocean and Indonesian Archipelago during an Enlightenment flurry of scientific inventory and economic growth. Through the 17th to 19th centuries uncompromising colonial expansion knitted disparate trading networks into a European-led global economy. Two key drivers at this time were the Dutch and British East India Companies which, it can be claimed, together founded modern capitalism. They not only raised vast revenues for their countries but influenced diet, fashions, and language, the British East India Company ensuring London would become the greatest city in the world and eventually its financial hub. India had proved pivotal in establishing early trade networks with a cloth centre established in Madras in 1639 (Bombay and Calcutta were added later), protected by a fort (Fort St George), and linked to East Indian trade. By 1700 there was a vibrant trade in gingham, calico, chintz, tea, and coffee. From these times came the Indian words dungarees, pyjamas, and bandana. Eventually Benghal was ruled by this private company, which was only taken over by the British government when difficulties arose.
This Western ascendancy, the Great Divergence, was injected with additional impetus as the Industrial Revolution in north-west Europe released the additional power of machinery using fossil fuels, modernizing transport and communication systems and creating industrial agriculture.
The most obvious presence of cultivated plants in our world, both spatially and in terms of biomass, has occurred through the use of land for food production. The Great Divergence bequeathed us a planet with about 11% of the land surface used for crops (UNFAO, 2015) although this figure can conceal much more extensive human influence. In Australia, for example, when grazing and rangeland is added to that of dryland and irrigated agriculture the total land surface influenced by human activity (including modification of natural plant communities) is closer to 60%. Human appropriation of net primary production totals about 25% (Kraussmann et al., 2013). Cultivated plants are thus a good indicator of human impact on the planet in today’s geological epoch, the Anthropocene.
The same is true for forestry. Though only about 5% of forests (which cover about 30% of the world’s land surface) are comprised of timber plantations a far greater percentage is actively managed, enclosed, or semi-natural.
We have given a superficial outline of the way plants useful to humans have gradually been drawn into a global economy; but how does cultivated plant globalization impact on the world?
Apart from the agricultural cereals of the Neolithic Revolution it appears that the first major influx of exotic plants to Britain occurred during its occupation by Roman garrisons (c. 45-410 CE). Archaeological research has revealed that during this period about 50 new food plants (mostly Mediterranean fruits, herbs, spices, and vegetables) were introduced by the Romans to supplement the local food (Van der Veen & Hill, 2008). Of these 50 species, 36 (over 70%) are now naturalised in Australia – a striking example of the cultural diffusion of plants across the planet, and a demonstration of how plants do not recognize the boundaries of our fields and gardens.
There are now near-cosmopolitan tropical and temperate urban weed floras. Weedy plants growing around the rails of Kew’s tube station Richmond, Surrey, are almost identical to those growing at Richmond Station, near the Royal Botanic Gardens in Melbourne, Australia – another stark reminder of the process of globalization and plant homogenization.
Today we confront the blurring of distinctions between natural landscapes and cultural landscapes. What is natural and what has been genetically altered? What is wild and what is cultivated? Already the management of alien and invasive species is now a major global expense, what will be the consequences if plants continue to escape from gardens and agriculture to mix and interbreed with native plant communities?
Today most of the world’s population lives in cities. We are not only divorced from wild nature but also from the cultivated plants of our rural surroundings, not knowing whether the vegetables and fruits we buy in supermarkets were grown nearby or in another country. The tomato we associate so closely with Italian cuisine is native to South America, chilli peppers of South America are widely grown in India, Australia’s only native commercial crop, the macadamia was, until recently, mostly sourced from Hawaii, the oil palm grown so widely in Indonesia and Malaysia is native to West Africa.
The urban areas of the world take up less than 0.5% of its land surface. The spatially widespread but few species used in the monocultures of agriculture and forestry contrast with the numerous ornamental species that are largely confined to urban parks and gardens. Garden plants are also, for both better and worse, globalized. As we have seen, we owe much of this to the English who remain the world’s greatest gardeners: ‘Other countries have quickly acquired (doubtless with the help of the RHS Plant Finder) the same plants we grow here, resulting in the internationalisation of the world’s garden flora.’ (Lord, 2017).
Just as uniting the world in trade has given us food choice, so the ‘internationalisation’ of garden treasures has given us an almost infinite plant palette for our cities, streets, parks, and gardens.
Since we benefit locally from global factors then we must think globally to minimize any negative impacts our horticultural diversions might have on the planet. The future is about sustainability – the cooperative integration of the world’s peoples to achieve an equitable distribution of the world’s limited resources with minimal social disruption and environmental impact. So how can we all help?
A global inventory of wild plants is now underway as a world flora. We need parallel inventories of cultivated plants including records and dates of plant introduction, commercial availability and use, also more detail on the historical factors that drove this process together with their environmental, social and economic impacts. In short, we need an ecological awareness of the role that ornamental plants are playing in global environmental history.
The fusion of plants with human affairs has made the interpretation of plant history as controversial, ambivalent, and complex as the interpretation of human history itself. Bound to the fortunes of civilizations and empires they have generated both misery and wealth but with the greatest impact through the period of European colonial expansion beginning in the 15th century and culminating in the economic botany of imperial Britain during the 18th and 19th centuries. The material comforts following the wealth generated by plant products existed alongside the horror of the slavery that produced them. Temperate European agriculture bequeathed pastoral landscapes and a culture of gardening to the colonial neo-Europes that, together with their mother-countries, would subsequently dominate the world.
What we can say for sure is that the human cultivation, biological modification, and redistribution of former wild plants has changed for all time the appearance and ecology of planet Earth, contributing to the most recent geological epoch we now know as the Anthropocene.