Biogeography, Food, and Landscape Change
Geog 334 @ CSUN
These lecture notes go with the other assigned materials. It will make sense if you also complete the other materials.
Opening Questions
•Where are plants and animals located? Why there? And how did they get there?
•What are some of the ecosystems and environments in Oceania?
•What does this mean for the kinds of food that are traditionally grown and eaten?
What is Biogeography?
The study of the geographic distribution of animal and plant life, and the processes driving these patterns.
The two main processes driving where plants and animals are located are dispersal and vicariance.
Dispersal
For islands originating as volcanoes, they begin their existence devoid of life. Every animal and plant on these islands is descended from ancestors that arrived via dispersal. In other words, they came from a different location to get there.
The three maps in this image show three methods of dispersal: storms and wind currents; bird flight paths; and ocean currents.
In Oceania's volcanic islands and atolls, certain plant and animal life have easy dispersal. These include birds, bats, flying insects, spiders, snails, fern spores, seeds, and other plant species.
Why is dispersal easy for them? Because of the large distances over the ocean between islands. This means that plants and animals have to travel across the sea or through the air to get from island to island. Wind can carry spores and small insects, even over large distances if they are uplifted into the atmosphere. Birds and bats eat fruit and carry seeds in their gastrointestinal tract and deposit them on other islands via defecation. Sticky spores and seeds also attach to bird and bat bodies that will fall off on other islands. Ocean currents can take fish and young sea creatures such as coral polyps and mollusks, as well as certain seeds such as mangrove seeds.
What faces poor dispersal? Anything that it too big to be easily carried by wind, water, or birds is not going to get to other islands by themselves. Large mammals, non-flying medium and small mammals, reptiles, amphibians, and freshwater species are some example of poorly dispersed wildlife in Oceania.
Vicariance
Whereas dispersal is when plants and animals move between locations, dispersal does not explain all biogeographical placement. We have clues about another reason because there are some species in Oceania that are extinct elsewhere in the world, and some species that are located in only some locations in Oceania but also found far away in other parts of the world.
Vicariance occurs when the habitat or territory itself is moved. For Oceania, this is reflected in continental drift. Two examples include the Tuatara, which is a lizard that is endemic to New Zealand (endemic means it is not found anywhere else in the world). Not only has it been extinct for 60 million years elsewhere in the world, it is the only remaining species in its taxonomic order. It survived in New Zealand as a remnant of the ancient continent of Zealandia, which itself broke off of the much older continent Gondwana. The tuatara survived in isolation from other predators.
Another example is the Araucaria genus of evergreen trees, which are located in two parts of the world: Australia and Melanesia, and South America. The same tectonic processes shifted the Araucaria habitats to different parts of the world.
Vicariance and dispersal often overlap as biogeographical processes. There can be dispersal first, and then vicariance as barriers were formed through continental drift.
Biodiversity in Near and Remote Oceania
Biodiversity refers to the number of species within a geographic area. Due to the way that islands tend to be closer to each other in Near Oceania than in Remote Oceania, this means there is more biodiversity in the Western Pacific than Eastern Pacific. This applies to land and sea life, and also include microorganisms.
There are higher numbers of fish species in Melanesia than in Eastern Polynesia, for example, because although open-ocean species of fish swim long distances, many fish species live near coral reefs. The longer distances between island chains in Eastern Polynesia and Eastern Micronesia make it more difficult for large numbers of species to disperse. Another example if the large fruit bat called the Flying Fox, whose territory includes Australia, Melanesia, and western parts of Micronesia and Polynesia. It's just too far for the Flying Fox to reach places like the Marshall Islands, Kiribati, and French Polynesia. Take the mangrove tree as another example. Its seeds float and are carried by ocean currents. However, it is not native to Hawai'i because its location far from other island chains and prevailing ocean currents did not bring mangrove seeds there in large enough numbers to sustain a population.
Biodiversity applies to microorganisms as well. Malaria is a deadly disease caused by a parasite that is transmitted through mosquito bites. Due to the distances that the malaria parasite would have to be carried within mosquitoes or infected people, the disease is only found in Near Oceania (PNG, Solomon Islands) and a few parts of Remote Oceania (eastern Solomons, and Vanuatu). In fact, mosquitoes themselves were not even in Hawai'i until Western contact.
So, what kind of wildlife is in Oceania, then?
A few years ago, a student taking this course said he had gone to French Polynesia for his honeymoon and was surprised that there were no monkeys or tigers, which he expected to see. Instead, what he found were birds, chickens, and dogs. This lesson helped him understand why. Native wildlife in Oceania is limited basically to birds, insects, and mollusks and arthropods (snails and crabs), along with ocean animals. Larger animals such as chickens and dogs were brought by people because they could not have made those voyages on their own! There are some interesting exceptions, however. Land-based mammal fossils have been found in New Zealand. This country is the remnant of an ancient continent, and so that mammal would have lived there before New Zealand became two islands. The same is true for kangaroos in Australia!
Main Ecosystems
Here are some of the main ecosystems in Oceania as explained in the reading materials.
Mangroves
- Trees and shrubs that grow in the tidal zones of wind-protected deltas, estuaries, and other muddy seashores of the tropics. Basically the only tree that can live in salt water.
- They are best developed on leeward and protected coastlines and are virtually absent from wind-exposed sandy coasts and headlands where there is an active surf.
- A benefit for people because they are a food source (habitat for fish, shellfish).
- A benefit for people because they help prevent erosion and they protect shorelines from storm surge.
- The destruction of mangroves and other coastal ecosystems is a significant environmental problem throughout the tropics.
Rain Forests
•Both lowland and montane forests
•Lowland: multilayered with closed canopies. The tallest trees exceed 37 m (121 feet) in height
•Montane: Simpler structure and fewer species because of higher elevation. Air rises from below and cools, creating clouds and rain. This is also called cloud forest. Thus, less solar radiation, and different plants grow (ferns, coffee).
Secondary Forests
•Where forests are allowed to regrow after a disturbance
•Quick growth because lots of sunlight
Coral Reef
Coral reefs are built around islands as the coral polyps (the young coral animal) settle on the seafloor and builds its exoskeleton as limestone.
There are around 1,600 species of coral!
Coral is really because it is an animal that eats plankton, but it also has a plant that lives inside it called zooxanthellae. The zooxanthellae use photosynthesis to convert sunlight into energy, which it shares with the coral animal. It also creates limestone as the surface on which it lives. So you could so that coral is animal, plant, and rock at the same time!
Coral reefs are important locally and globally. Here are just a few reasons.
They protect coastlines from waves and storm surges that happen in hurricanes, typhoons, and tropical cyclones.
They provide habitat and shelter for many marine organisms.
They help with nutrient cycling.
Local and global fishing depends on coral reefs because fish spawn there and spent time before making their way to the open sea.
Food and Agriculture
What does biogeography, climate, and soils tell us about foods grown in Oceania? Here are some of the main traditional foods. There is more explanation in the reading materials.
Many of the traditional foods were brought into Oceania by indigenous inhabitants, but some were domesticated within Oceania. The chart below shows some notable plants used as food:
- Breadfruit, a starchy fruit that when roasted, actually tastes and feels like bread!
- Sago Palm, whose fruits are eaten in many countries
- The Australimusa banana, whose peel is orange-red and was domesticated through agriculture in New Guinea.
- Kava, a plant used to make a traditional drink but is not eaten
- Pandanus, which provides fruit as well as leaves that are used to create mats and baskets
- Wild bananas, in contrast, have very large seeds and very little edible fruit.
- Sugar cane actually comes from New Guinea!
There are also many root crops, which form the basis of most traditional foods in Oceania. These include, taro, giant taro, swamp taro, tannia, yams, cassava (manioc), and sweet potatoes.
In the United States, sweet potatoes are mistakenly called yams. If you're shopping and see yams for sale in the U.S., you're almost certainly looking at sweet potatoes. True yams (Dioscorea spp.) are not even closely related to sweet potatoes (Ipomoea batatas). While sweet potatoes can usually be held in one hand when fully grown, yams can grow for years and reach sizes of many feet long!
Local Names
Crops that have an indigenous history (as in, they've been part of society since ancient times) usually have local names. Here are a few examples.
Swamp taro is known as puraka in the Cook Islands, babai in Kiribati, and simiden in Chuuk. In Papua New Guinea, the pidgin language Tok Pisin calls it swam taro; but it will have unique local names in PNG's many indigenous languages.
For instance, taro (Colocasia esculenta) is known as aelan taro in Vanuatu's pidgin language of Bislama. In the indigenous language of the western side of Ambae Island in Vanuatu, it is called Ngweta.
Taro
A few different species of plants are called taro. We'll focus on one (Colocasia esculenta). The main edible part grows underground, but leaves are also edible.
- Taro (Colocasia esculenta)
- Swamp taro (Cyrtosperma merkusii)
- Giant taro (Alocasia macrorrhiza)
- Tannia or Fiji Taro (Xanthosoma sagittifolium)
Taro (Colocasia) is very important nutritionally, historically, culturally in Oceania. It is an integral part of the environment.
Colocasia esculenta was domesticated in Papua New Guinea and has been farmed there for 10,000 years. Along with yams, it is the oldest indigenous food crop in Oceania. The edible parts include the root, stem, and leaves.
Case Study: Kalo (Taro) and Ka'ala Farm, Hawai'i
Taro is called Kalo in Hawaiian language. A group of CSUN geography students visited Ka'ala Farm to see the kalo terraces maintained by Eric Enos. This is a cultural learning center that connects agriculture with care for land following traditions of ancestors.
Case Study: Pacific Research Garden at CSUN
Dr. Drake has a research and teaching garden on campus, focusing on taro and sweet potato. We are tracking plant growth, water conservation, and weather variables. Below are photos of a progress check -- five months into a seven month growing season.
Sweet potato, taro, and island cabbage growing on campus.
Progress check on corm development. Taro corms are the underground part of the plant that is eaten.
Cassava
Cassava (also called manioc, yuca, or tapioca in various parts of the world) and sweet potato are grown easily in Oceania countries and form an important part of traditional cooking, but were more recently introduced into the region. Because of this reason, they are referred to by very similar names across Oceania.
Cassava originates in Brazil as was introduced after European colonialism.
Sweet Potato: How Oceanians traveled to South America and back
The Sweet Potato has a more interesting story. It originates in the Americas but was already present in Oceania before colonialism because Polynesians met Native Americans before Europeans did .
Across Oceania, sweet potatoes are called variations of the word kumara or kumala. This is nearly the same as some of the indigenous names in the Americas such as camote and kumar.
It gets more interesting because there are sweet potatoes in archaeological sites in the Cooks Islands dating as far back as the year 1200. Genetic research has also found certain Polynesian DNA with Native American ancestry dating back to around 1150.
The linguistic and archaeological evidence supports an argument that Polynesians, who were already skilled at ocean voyaging, reached the Americas long before Europeans.
As a further sign of the incredibly interconnectedness of all of Oceania, sweet potatoes are grown and known by the name kumala all over--not just in those countries closest to South America. The sweet potato arrived and entered indigenous trade networks spanning from the Marquesas Islands to Hawai'i to New Zealand and the Solomon Islands.
There were actually three introductions of the sweet potato into Oceania. The first was by indigenous Oceanians, which is called the "kumara line" in the map below. Spanish and Portuguese colonists also brought sweet potatoes across the Pacific from their territories in the Americas.
Map showing transport routes of sweet potatoes from the Americas into Oceania ( source ).
Coconuts
Let's talk about another staple of tropical food, coconuts. It's not just a food, though: it is a multi-purpose plant.
Map of the global range of coconut growth, in the tropics.
Coconut trees (Cocos nucifera) are in the palm tree family, and they need a few conditions to grow well.
- Warm temperatures and sunny year-round
- High humidity year-round
- Regular rainfall year-round
Other types of palm trees grow better in dry environments, which is why you see lots of palm trees in California, but no coconut palms!
Cross section photo of coconuts showing the outer husk and the edible coconut flesh.
In terms of traditional food and nutrition, coconuts are most often consumed as coconut milk. This is prepared after removing the outer husk, the brown shell is cracked in half and grating tool is used to grate the white flesh. Then the grated coconut is squeezed to remove the liquid.
The coconut tree provides many other uses as well. A couple of examples include: coconut husks make great kindling for starting cooking fires; you can make a great broom out of the spines of the palm frond.
Coconut grating tool and grated coconut in a bowl.
Dry coconut husks that make great kindling for fires.
Parts of the coconut palm frond can be used to make high quality brooms.
Bananas
There are more than 1,000 types of bananas, and they are another staple in Oceania food. They come in a diverse shapes and sizes. In Oceania, this includes dessert bananas (the kind you just peel and eat, which is the one most familiar in American supermarkets); plantains that are cooked; and even very large, starchy bananas that are baked and eaten like potatoes!
A few examples of different banana varieties in Oceania.
Traditional Foods and Nutrition
The staple foods of traditional cooking across Oceania relies on the root crops listed above, along with breadfruit, bananas, and coconut. Root crops and breadfruit are cooked either whole or grated into a paste and made into a casserole. Coconut milk is used as flavoring when it is used to baste baked vegetables or fish, and coconut milk is also used as a binding agent when mixed with grated root vegetables.
Greens and leafy vegetables: Presently, a range of leafy greens found around the world are grown in gardens in Oceania. However, traditionally, the main leafy green is Abelmoschus manihot, known in various Pacific Island countries as Island Cabbage, Aibika, Tongan Spinach, Bele, and others. It is very nutritious: high in Vitamins A and C, iron, and protein.
Abelmoschus manihot (Island Cabbage) plants next to a house that are about 2 meters tall. Photo by Luke Drake.
Traditionally, protein sources included certain root crops like taro, and meat such as fish, chicken, and pork. Chickens and pigs were brought into Oceania with indigenous settlers and have been part of the landscape as long as humans. The fruit bat commonly called flying fox (Pteropus spp.) is eaten less frequently, but it has been a food source since ancient times in those parts of Oceania and Australia where they live. Such bats only eat fruit and are different than insectivorous bats elsewhere in the world. More recently, other livestock such as cattle and goats provide other sources of meat-based protein in Oceania cooking.
Traditionally speaking, foods were flavored mainly with salt (from saltwater) and coconut milk. Due to challenges in biogeographical dispersal, there are not a lot of other spices used in traditional cuisine simply because they were not available (for example, cinnamon, pepper, vanilla, etc.) compared with other regions such as South Asia and Southeast Asia.
Also, please note that rice is not part of traditional cooking for most of Oceania, because the environmental conditions were not suitable for rice cultivation by indigenous settlers (although rice is now grown in some countries with the introduction of modern agriculture). Rice is currently eaten in large quantities across Oceania, however, which along with bread and sugar has contributed to non-communicable diseases such as diabetes and high blood pressure. Whereas rice has long been part of traditional cooking in Asia, it was never this way in Oceania and today it is a cheap food source.
Research Example
Let's combine some of our lessons from the past two weeks in a research example. The following project's objective was to understand flood vulnerability in Fongafale Islet, in Funafuti Atoll, in the country of Tuvalu.
The research objective was to identify places vulnerable to flooding and explain why this is happening. The data included historical aerial photographs and recent satellite images, along with topographical surveys that indicated changes to the physical landscape. Political and economic data were also used in order to understand shifts in population under colonialism and international mining jobs.
The project found that housing near the airport was subject to flooding due to a variety of factors. The airport that was built during World War II was built with excavated sediments from elsewhere in the island and used to fill in swamp and marshes that were naturally prone to flooding. This area served as space for additional housing for former mineworkers returning to Tuvalu after the closure of phosphate mines outside the country. Due to the geographic concentration of jobs in cities, those workers and families moved to Funafuti instead of elsewhere in the country. Due to lack of urban opportunities elsewhere in the country, housing expanded into the former marshes and swamps that can been filled. However, since the underlying sediment is still prone to flooding, this places those areas at risk. Those families are thus at a disadvantage economically and in terms of environmental hazards.
Land cover maps and Transect surveys showing topographical change in Funafuti Atoll.