Histories have tended to take regional perspectives of environmental change of this kind, so we are relatively new to the assumption of a global perspective. This is no doubt enhanced by the fact of globalization – that we have now entered a phase of history in which the world’s plant resources are, in a practical sense, available to all: facilitated by rapid long-distance international trade, refrigeration, and technology that can create artificial climates on a grand scale.
Today, with the wisdom of hindsight, we realize that there has been an inevitability about this process of Cultivated plant globalization. Our task is to uncover the reasons why this global homogenization of cultivated plants (the global plant resource) happened the way that it did. What were the geopolitical historical forces in operation; what factors influenced plant selection; why did some countries display a propensity for plant transport and distribution and not others; what were the relative influences of history, geography, biology, politics and culture, ecology, technology, transport systems, and so on; what were the major periods and patterns of transfer and exchange; and what have been the advantages and disadvantages of this process that we might take into account for the future management of global vegetation?
We are still neophytes in the study of cultivated plant geography, partly because major changes have occurred in relatively recent times. What have been the key determinants of today’s global distribution of cultivated plants?
Studying cultivated plant geography confronts us with all the difficulties of biological systems. Should our approach be historical, cultural, biological, ecological, social, even political?
There is a further pair of interconnected dimensions to be considered. First, the criteria defining plant transfer, the three selected here being: numbers of species (successfully introduced); area of land occupied, and direct environmental impact (influence on provision of Ecosystem Services). And, second, the economic, social, and indirect environmental influences and consequences at work. Direct environmental impacts are physical impacts on the land and its organisms: indirect impacts relate to resource consumption and waste. This synthetic approach provides us with an overview.
Another approach would be cumulative, extending our knowledge by comparative analysis of individual plant biographies of plant commodities.
Our focus is cultivated plant geography and since we are primarily concerned with actual plants and their distribution not possibilities then biological determinants become of less significance than human agency.
Commonfolk travelled with seeds. Australian settlers engaged in a black market of natural history specimens.
Ambrosi, M. 1997. The Wild and the Sown: Botany and agriculture in Western Europe, 1350-1850. Cambridge University Press: Cambridge.
Brockway, L. 1979. science and Colonial Expansion: The Role of the British Royal Botanic Gardens. Academic Press: London.
Grove, R. 1995. Green Imperialism.
Griffiths & Robin
Flannery The Future Eaters. An environmental history of Australia.
The separation of the historical and scientific domains in academia impede research.
We need quantitative estimates of the relative impacts of the activities of, on the one hand, formal processes recorded as the institutional history of scientists and their organisations which have clear documentary trails and, on the other, informal networks of knowledge, transfer and exchange.
Values: what are the social attitudes and beliefs concerning plant transfer and its effects on the environment?
Criteria used to assess patterns and measures of transfer: numbers of species (successfully introduced); area of land occupied, and environmental impact (influence on provision of ecosystem services). Can we detect economic, social, or environmental patterns in this process?
Temperate agriculture depended on suitability for both plants and animals in Australia, New Zealand, South Africa, Argentina and Uruguay.
The interpolation of cultivated plants into the natural vegetation of the planet has been largely a consequence of human-determined factors (although the appropriate environmental conditions are clearly a pre-requisite). For convenience, the human dispersal of cultivated plants has been divided into four major historical phases: the Agricultural Revolution, the development of Bronze Age urban civilizations and trading networks, the intensification of commercial links between East and West, and the Great Divergence. Also for convenience the kinds of plants being dispersed during these historical phases have been divided into five economically- and socially-significant groups: cereals and staple crops; spices and medicinal plants, horticultural crops, timber trees, and ornamental plants. To this may be added the recalcitrant category of unwanted plants or weeds.
We have selected three ways of measuring plant transfer: numbers of species (successfully introduced); area of land occupied by the new introductions; and direct environmental impact (direct impact on environments). The historical dimension concentrates on economic, social, and environmental factors, the latter as indirect impacts relating to resource consumption and waste. This synthetic approach provides an overview and can be combined with the study and improvement of individual plant biographies.
Historically, key research into the geography of cultivated plants has focused on major crops and their geographic origins (see Vavilov ) and attention to environmental factors like those that determine wild plant biogeography (Good 1964) and the uneasy disciplinary mix of botany and history.
Much of the distribution of cultivated plants has been part of formal, official and recorded policy. This includes plants distributed by government departments, botanic gardens, academicians and university employees, individual professional collectors and those sent out by horticultural and agricultural societies and official exploration. Among the private (and often unofficial) distributors were nurserymen, entrepreneurs, missionaries, religiosi, adventurers, settlers and private individuals.
GEOPOLITICS OF CULTIVATED PLANT DISTRIBUTION
Agricultural Revolution (c. 12,000-2,000 BCE)
See also Neolithic Revolution and Aboriginal Neolithic Revolution
Anthropogenic landscape change in prehistory was more likely due to the deliberate burning of natural vegetation and interference with animal food chains than with the transport of plant species beyond their natural distribution range. Gradually, across the world, harvesting of wild food plants entailed increasing plant husbandry that took various forms. So, for example, Australian explorer Thomas Mitchell in 1846 observed native grasses arranged in stacks along the Darling River. The seed heads were threshed by Aboriginal womenfolk before grinding stones were used to make a form of bread (Mitchell, 1848).
The first substantial human transformation of natural landscapes occurred at sites of plant and animal domestication. This occurred independently in about ten centres across the world, the earliest in the Near East in about 12,000 BCE. Settled agricultural communities growing mainly cereals, but often other crops as well, sprang up along major river valleys where there were fertile sedimentary soils – the Nile in Egypt (emmer wheat and barley processed into bread and beer), Tigris and Euphrates in Mesopotamia (wheat, rye, barley), Yangtze and Yellow Rivers in China (millet and rice), and the Indus Valley in India and Pakistan (wheat, barley). In Mesoamerica maize was domesticated in Mexico in about 7500 BCE, its use then spreading into North and South America. There is also evidence for small-scale agricultural plantations in highland New Guinea that date back about 10,000 years (taro, banana).
Agricultural practices spread outwards from their centres of origin. In Europe, this was from the Near East along the Mediterranean coast to Italy and the Iberian Peninsula where cereals were established in about 5750 BCE although it took about 8000 years to reach the British Isles and Scandinavia in Europe’s north-west.
This phase of history, known as the Neolithic Agricultural Revolution, eventually resulted in human communities whose scale and degree of organization made possible the construction of cities and societies whose capacity for conquest, commerce, and technology would ultimately connect the world.
Bronze Age civilizations (c. 4,000-750 BCE)
In one of humanity’s greatest social transformations small agricultural communities evolved into hierarchically governed Bronze Age cities and city-states.
Western cities originated around 4000 BCE and were located in the Fertile Crescent that passed from Egypt’s Nile to the Eastern Mediterranean and Mesopotamia. The Indian Harappan Civilization (c. 3300-1300 BCE), founded on earlier cultures, consisted of numerous settlements along the Indus River, trading with Mesopotamia and producing cotton, wheat and rice, while people of the Chinese Bronze Age (c. 2000-750 BCE), like those living in the Xia Dynasty city of Erlitou in the Yellow River Valley, ate bread and cakes of millet and barley and, as in the West, drank Beer.
Urban living changed, in a profound way, the relationship between humans and nature as material culture became more elaborate, creating fundamental urban spaces and mental categories that remain with us today.
Urban spaces were an expression of social functions and values and special horticultural treatment was often required for: palaces, government, and administration; domestic housing; markets, meeting places, workshops, and entertainment; temples and burial sites; public thoroughfares, parks and gardens. Mostly on the fringes of the cities and beyond were the market gardens, vinyards, and grain fields.
In these cities were the beginnings of gardening and urban design.
The advent of walled cities meant that humans, once a part of nature, now had new mental categories that distinguished between the natural and man-made, wild and cultivated, public and private, formal and informal, sacred and secular, work and pleasure, utility and luxury, and all were applied to the selection and use of plants. From this time on, wild nature would be steadily enveloped by the boundaries and structures created by urban and rural concerns.
Plants were now part of the exchange taking place between urban centres, even taking on a new economic role as secondary products within market economies: olives as olive oil and grapes as wine. Trade had become a driving force in social development as cultures, technologies and plants diffused over ever wider geographic areas.
East-West trade (c. 3500 BCE-1500 CE)
See also the Silk Road
Along with the convergence of independently-derived agriculture came a cultural diffusion between the civilizations of East and West which were separated geographically by the barrier of inhospitable Central Asian deserts and plains.
From about 3300 to 1200 BCE a western trading network connected Bronze Age cities of the Eastern Mediterranean Minoans and Mycenaeans to the Near Eastern Cyprians, Egyptians, Hittites, Mitanni, Assyrians, and Babylonians. This trading bloc had a peripheral western side-branch, the Amber Road, which passed along the great European rivers to the North Sea and Baltic. A large New Kingdom Egyptian navy traded grain, wine, timber, olive oil, incense, and perfumes in the eastern Mediterranean, even importing cedar from the region of today’s Lebanon for its shipbuilding. These ships also plied their trade along the Nile, Red Sea, East African, and Arabian coasts on routes that connected to India and beyond.
A brief Dark Age then preceded Classical antiquity (900 BCE-500 CE) with its clashes of Greek and Persian empires. An impressive Persian Royal Road, built in about 500 BCE, extended nearly 3000 km from the city of Susa on the Tigris in the East to coastal Smyrna (modern Izmir in Turkey) in the West. Following a Greek defeat by Persian troops the ancient Macedonian military hero Alexander the Great in 326 BCE penetrated east as far as the Indus River spreading Greek culture into the communities that had evolved from the Mesopotamian core and which had been trading with India for several thousand years. The Greek empire, along with that of the seafaring Mediterranean traders, the Phoenicians, eventually succumbed to what would become the world’s largest empire, that of Rome.
The Silk Road was an ancient divided caravan route connecting China and Japan with the Mediterranean and reaching its height during the Han Dynasty (202 BCE– 220 CE) when China had a monopoly on silk trade with the eager Roman market. A southern offshoot met the Indian Grand Trunk Road and reached further south, linking to the Incense Route which traded frankincense and myrrh across the Arabian Peninsula and Horn of Africa. Overland trade was slow and risky so with improved shipbuilding maritime commerce became more popular. By the first century CE Roman ships were sailing down the Red Sea to access spices from the Indian west coast.
Following the fall of Rome, Christianity took hold across Europe, but by 750 CE the new religion of Islam had completed successful conquests into North Africa, the Iberian Peninsula, the Middle East, and Central Asia up to the boundaries with India and China. Much of the ancient learning of the Classical world, including the accumulated medicinal wisdom, now passed to Muslim scholars. Eastern and southern Mediterranean Europe then gave way to the Muslim Ottoman Turks who built an empire that flourished from about 1300-1600. Muslim and Indian traders now had a firm grip on overland East-West trade routes
In the East, from about 1100 to 1430, China dominated Asian trade with a professional Ming navy based on the Yangtze, and a thriving trade along the Silk Road. This outward-looking policy culminated in seven maritime expeditions between 1405 and 1433 led by Admiral Zheng-he in ships that dwarfed European galleons and penetrated the western oceans as far as East Africa and the Red Sea. Collections of exotic animals, like giraffes, were returned to China but little international exchange was established.
Remarkably, China and Japan then turned inward thus prompting illegal private trade and piracy. In China, ocean-going grain shipments were replaced by canal barges after the Ming Dynasty completion in 1415 of renovations on the vast Grand Canal.
With the fall of Constantinople to the Ottomans in 1453 refugee scholars fled to Italy, settling in Florence and commercial city-states like Genoa and Venice where a Western Cultural Renaissance was stirring.
The dramatic change in world landscapes that has occurred over the last 200-300 years is largely a consequence of what historians call the Great Divergence, a phase of rapid economic growth emanating from Western Europe and spurred on by rapid advances in science and technology, transport and communication, Enlightenment thinking, and an Industrial Revolution. Maritime trade would play a major role in this transition.
Claudius Ptolemy (c. 100 – c. 170 CE), an academic of Greco-Roman Alexandria, had produced a map of the Classical world that served European mariners for about 1300 years, but in the century between 1470 and 1570 in the Age of Discovery, European explorers charted the coastlines of the Atlantic, Indian, and Pacific Oceans to produce a rough semblance of today’s world map, continuing until the task was effectively completed by 1800.
This period of European colonial expansion began with a search for a sea route to the Spice Islands that would by-pass expensive overland Arab merchant middle-men. First Portugal, then Spain and the Netherlands, developed colonies and trading empires built on the initial desire to monopolize the spice trade. European interests were injected, often forcefully, into foreign lands as trade routes passed to European powers. Spain established a strong trade network across the Atlantic with the New World while the Portuguese commandeered trading hubs in the Indian Ocean and Far East. Much of the Portuguese trading empire was later seized by the ascendant Dutch during a 17th century golden age before succumbing, in turn, to the ambitions of France and England in the 18th and 19th centuries. In 1605 Clusius, the first director of Leiden Botanic garden, published Exoticorum Libri Decem which was the first account of plants imported to the Netherlands.
Eventually England forged the world’s largest ever empire that reached its peak in the century between the defeat of Napoleon in 1815 and the eve of the First World War in 1914, in an era of critical significance for environmental and economic history, and for the global distribution of cultivated plants.
During the Great Divergence, colonial European powers introduced European people and institutions to Africa, India, the Americas, Asia, and Australasia in an expansion of Europe that was a contraction of the world (Drayton, 2000, p. xiv). European agriculture was established in the temperate European colonies; tropical crops were exchanged between the East and West Indies to become distributed throughout the tropics; and lucrative plantation crops were grown across the world, but mainly in the Americas. While European-style agriculture, ornamental horticulture, and silviculture were exported to these ‘Neo-Europes’ (Crosby, 2004) garden plants were being imported to Europe by means of trade and eager plant hunters, explorers, missionaries, and scientific collectors.
Between 1650 and 1850 the world population doubled, increasing demand on all the world’s resources, including the need for food, forest products, and garden ornament. The Industrial Revolution, energized by fossil fuels, provided steamships, railways, automobiles, and planes, to open up inland regions of all continents to further development. Then after World War II, the world entered a yet more intensive phase of globalization and economic activity, the Great Acceleration when, in the short period between 1950 and 2000 the world population again doubled and America became the leading world power.
Human population growth in the industrialized world has now slowed, being greatest in low-income countries, but the consumption of plant resources, by developed countries especially, weighs heavily on the environment.
Good, R. 1964. The Geography of the Flowering Plants. Longmans: London
Tightly knit to the story of urbanism is the story of trade and trade connections. Relatively recent systematic, problem-oriented research on the Swahili coast and its hinterland has enabled us to understand the ecological, cultural, and economic milieu in which complex chiefdoms and urban polities arose in Eastern and Southern Africa in response to global long-distance exchange in the Indian Ocean. Here are some snapshots about East Africa’s connections with regions to its east and west:
East Africa’s Connections with Asia
Many of the crops that are now staple foods in much of sub Saharan Africa were first experimented with and domesticated in Asia. Some of the African domesticates including sorghum, millet, and coffee are widely consumed by contemporary Asians as staples.
Ancient connections between Africa and Asia, including China, are exhibited in the numerous archaeological remains that have been recovered at many sites across the continent. Artifacts including Indo-Pacific beads, glass, Middle Eastern glazed pottery and jewelry, and Chinese stoneware and porcelain, among others, have been recovered at nearly all medium-to-large settlements along the Eastern and Southern African sub-continent from the Tang Dynasty (618-907 CE) to the present. This non-African materiality bears witness to the global connections, contributions, and complexity of Africa’s past and systematically dismantles the long-held narrative that Africa was isolated from Eurasia and, with the exception of north Africa, contributed precious little to global civilization.
East Africa’s connections with Eurasia and the Middle East
Archaeologists and historians have documented evidence of biological, cultural, linguistic, commercial, and technical communication between East Africa and the Middle East beginning from the early first millennium CE. The Periplus of the Erythrean Sea, a third century mariner’s guide presumably written in Alexandria, mentions that iron lances, hatchets, daggers, and awls made at Muza, east of Aden constituted trade items destined for African markets.
Trade items from the East African coast made for foreign markets in India, the Middle East, and China included marine products- such as tortoise shells and ambergris; animal products- like ivory, rhinoceros horns and cat skins; and vegetable products- like mangrove poles, wood, and timber. Turtle shells and ambergris were in high demand in India and China. Ivory, rhinoceros horns, and leopard skins were exported to India, China, and the Persian Gulf. Timber for building and aromatic products were needed in the Persian Gulf until relatively recently. Demand for African timber in the Gulf was high enough to be reported by Ibn Hawqal c.960 CE who wrote that houses in Siraf were built of wood from the country of the Zinjs.
Textiles, including silk and cotton were spun in Mogadishu, Pate, Zanzibar, Kilwa, Mahilaka, and other major towns and their products widely traded in Eastern Africa reaching as far as Egypt. Upon their visit to Pate Island (Kenyan Coast), the Portuguese were impressed by the high quality silk manufactured there. Mining and the working of iron was an important industrial activity at Malindi and other Swahili towns.
The superior quality of iron products made in East Africa was impressive enough to be added to the list of African exports to India by Indian merchants who regularly visited the coast with the aid of annual monsoon winds. Al Masudi who visited East Africa in 912 CE left one of the most cogent descriptions of the iron industry on the coast in his The Meadows of Gold and the Mines of Gems.
All of the above findings contradict the long-held misconceptions about pre-industrial Africans and their connections with the rest of the world during the Middle Ages. During the Middle Ages, increasingly after the ninth century, East African towns were important centers of production and venues where trans-continental exchange of goods and natural resources took place.