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12/01/2022

Citizen science: how ordinary people can guard Cape Town’s biodiversity
Right now, you might be harbouring a killer: one so small it’s hidden in the sole of your hiking shoes. These tiny murderers won’t harm you in the short term, but they can be deadly for the plants that are crucial to food security and biodiversity conservation.

New research we conducted with our colleagues shows that some of these plant-killing microbes, known as Phytophthora, can be detected in urban areas before they get the chance to escape and spread into the natural environment. Phytophthora is a Greek word that best translates to “plant destroyer”. Species in this group are responsible for some of the worst plant disease epidemics in history. The Irish Potato Famine in the mid 1800s was caused by Phytophthora infestans, a species that still plagues tomato and potato fields around the world.

Another species, Phytophthora cinnamomi, is known as the “biological bulldozer” in Australia. It has affected thousands of plant species and is considered a top environmental threat. It also occurs in the Cape Floral Kingdom of southwestern South Africa, a hugely important biodiversity hot spot that encompasses the city of Cape Town. Thanks to citizen scientists engaged as pathogen hunters, we have also learned that other “plant destroyers” are present in the Cape Floral Kingdom.

Many professional staff members from botanical gardens, nature reserves and national parks have already contributed to the project’s findings in the natural areas surrounding Cape Town. Now we’re asking citizens to help look for plant destroyers in the city’s urban areas.

This study is important because our best chance of preventing a plant disease epidemic is to detect the species before it spreads into natural or agricultural environments. Humans – the very “carriers” who can spread dangerous microbes unthinkingly from their equipment and shoes – can instead become the first line of defence against a possible microscopic invasion.

Dangerous species on the move
Cape Citizen Science is a project supported by the DST-NRF Centre of Excellence in Tree Health Biotechnology, the Forestry and Agricultural Biotechnology Institute at the University of Pretoria, and Stellenbosch University.

It engages non-scientists in ecological and microbiological research. Currently the project facilitates research about the diversity and distribution of Phytophthora species in the Cape Floral Kingdom. The results provide baseline knowledge about the plant destroyers already present in natural areas. But we fear that other species, which have not yet “escaped”, may be hiding in urban areas.

We suspect most of these species are limited to the soil. That means they can’t “escape” unless the soil or infected plant tissues from the same area are moved. The worst case scenario would be the discovery of a wind-dispersed species such as Phytophthora ramorum – the organism that causes Sudden Oak Death in the US. Finding these kinds of species before they can be blown away is important.

Citizen scientists conducting research.
Our research suggests that surveys in urban environments could lead to the detection of Phytophthora species before they escape into the natural environment. Preventing their escape or spread is critical for preventing the damage these “destroyers” can do in natural or agricultural settings.

Biodiversity protectors
This is why we’ve launched a new phase of Cape Citizen Science called “The Cape Town Hypothesis Test”. A hypothesis is an idea that can be tested scientifically. In this case, we hypothesise that there are different Phytophthora species in Cape Town’s urban areas than there are in the area on and around Table Mountain National Park, a world heritage site that’s a major part of the Cape Floral Kingdom.

Citizens participating in the project could be the first to discover a new introduction of a Phytophthora species in South Africa. Detecting such a species before it spreads to the natural environment is critical for protecting South Africa’s incredible biodiversity and preventing destruction from other potential “biological bulldozers”. If a different species is detected in the urban areas then local communities, researchers, stakeholders and officials can prevent the spread into natural areas.

From November 2017 until the end of February 2018 we’re seeking ordinary people’s help to test our hypothesis. This involves the collection of soil and fine roots from under sick plants in Cape Town’s urban areas. Instructions and examples of sick plants have been made available online. Samples will then be tested in a laboratory at Stellenbosch University for the presence of a Phytophthora species.

We have also designated 15 important areas to collect samples. A map of these areas is available on the website. Once a sample is submitted from one of those areas, the map areas will change colours and a GPS point will be added with the citizen’s name (if they wish). By sampling these areas, the study will ensure broad coverage of Cape Town’s urban areas.

Testing hypotheses is an important part of scientific research. The results of this study can be used to inform decisions to protect the natural areas surrounding the mother city. For example, finding a different species in the urban areas may be enough to justify boot cleaning stations at the base of the Table Mountain Aerial Cableway – a way to keep those tiny murderers from “hitch hiking” into natural and agricultural areas on our boots.

12/01/2022

Heading back to the office? Bring these plants with you to fight formaldehyde (and other nasties)
Humans have built high-rises since ancient Roman times, but it wasn’t until the 20th century that they became the default work space for a significant slice of the world’s workers. While these buildings are certainly efficient, they can cause real health issues.

Office buildings, where many Australians spend much of their time, are even worse than apartment buildings. Cubicles in offices usually consist of partitions made of particle board and vinyl carpet, synthetic flooring, a particle board desk and plastic or synthetic office chair, mostly lit by artificial lighting. The lucky few get natural light and a view from a window, but poor ventilation still spreads germs.

Read more: Why apartment dwellers need indoor plants

One excellent way to combat both sick days and stress is by filling your office with plants. Ideally, you want plants that will “scrub” the air of pathogens, improve the office’s mix of bacteria, and survive in low light with little care.

Fight formaldehyde (and other nasty chemicals)
One of the many chemical compounds given off by synthetic office furnishings is formaldehyde, which can irritate the mucous membranes of the eyes, nose and throat, and also cause allergic contact dermatitis.

Irritation of the eyes and upper respiratory tract, as well as headaches, are the most common reported symptoms of exposure to formaldehyde toxins. Other harmful chemicals in the office may include benzene, ethylbenzene, toluene and xylene, and even ammonia from cleaning products. High levels of carbon dioxide breathed out by a roomful of colleagues can give the room that “stuffy” feeling, particularly if there is no air conditioning.

Indoor plants will purify the air, reducing volatile organic compounds, including formaldehyde.

A NASA clean air study tested common indoor plants for the ability to filter pollutants, and found many are very effective at removing multiple kinds of organic compounds from the air (this chart is very handy for finding high performers).

To best remove indoor pollutants, try for one medium-sized plant per 2.2 square metres. Look for species with large leaves (the more leaf surface area, the more efficient it is).

Improve indoor bacteria balance
There are already trillions of bacteria in high-rise offices, but only a limited amount come in through open windows and air conditioning from the outdoor environment. Most of the bacteria, fungi and viruses come from people; we leave behind a microbial cloud from our skin wherever we go.

The office environment then creates new habitats for microbial communities that may be quite foreign to human skin, and may not be good for your health.

Beneficial bacteria on indoor plants and in their soil are an important addition to the office, stabilising the ecology of the built synthetic environment.

Plant-associated bacteria could also help to avoid outbreaks of pathogens by enhancing microbial biodiversity and balancing the complex network of the ecosystem. A wholesome balance may reduce the incidence of viral illness and the number of sick days among staff.

It’s not just the size of the plant that’s important here. Larger pots mean more root mass and soil surface for helpful bacteria and root microbes.

Beat stress
Over the past 30 years, research has shown that green spaces promote public health, and that contact with nature can shift highly stressed people to a more positive emotional state. One study identified eight ways people perceive green urban spaces (described as Serene, Space, Nature, Rich in Species, Refuge, Culture, Prospect, and Social) and confirmed the importance of considering plant life when creating public places.

Offices, particularly those with many people, poor ventilation or low natural light, should also consider plants and green spaces a necessity.

There are a few basic principles for a good office plant. It must be hardy and easy to maintain, and able to survive without water over weekends (or when the regular plant-carer goes on holiday). Many plants will do the most good in cubicles and spaces away from windows, so they need to be adapted to low light.

It’s also a good idea to avoid plants that flower extravagantly, which may cause allergic reactions. Check with your colleagues before introducing new plants.

Read more: Hay fever survival guide: why you have it and how to treat it

Some of the best all-rounders across these categories are Devil’s Ivy, Bamboo Palm, Kentia Palm, Variegated Snake Plant (also known as mother-in-law’s tongue), and the Peace Lily, but there are many beautiful plants that will improve your atmosphere and mood.

So if you’re heading back to work in an office soon (or know someone who is), why not bring along an indoor plant?

12/01/2022

Plant fossils have a lot to teach us about Earth’s history
There’s a particular feeling of excitement that comes from receiving a gift. It’s a feeling of the unknown, of anticipation – and then you unwrap the package and find something spectacular.

As palaeontologists, rocks are our idea of a great gift. That’s because when you crack them open, you might well find a fossil. And we aren’t talking about dinosaurs: our area of specialisation is palaeobotany. This involves hunting for plant fossils which can tell us a great deal about the landscapes of past ages.

South Africa is home to a range of lesser known and neglected plant fossils, called the glossopterids. These trees once grew in vast swamps along with ancient plant groups such as ferns, horsetail ferns and clubmosses. We know from a few scattered reports that this amazingly rich fossil resource extends across much of Africa, particularly in Namibia, Zimbabwe, Mozambique and further north into Zambia, Tanzania, Kenya and even Madagascar.

Some may wonder why fossils matter. Plants never get as much attention as South Africa’s famous rich and diverse fossil heritage that range from some of the earliest evidence of life through to its famous hominid collections. Glossopteris, for instance, has not been well studied in South Africa. It’s still poorly understood.

There has been work done in different parts of the world. However, it is not detailed and each region uses its own system to try and understand these fossil plants. South Africa is lagging behind: there are two employed palaeobotanists in the country, while entire research teams exist in other parts of the world.

Yet plants can reveal a great deal about past environments and climates. If we have any hope of understanding South Africa’s ancient past, scientists need to be able to reconstruct entire ecosystems, starting at the bottom of the food chain. Glossopteris dotted ancient landscapes before dinosaurs ever walked the earth, and before a single flower had bloomed. As such, it should be closely studied.

What we know
About 300 million years ago Earth entered what’s known as the Permian period. During this time, and until about 252 million years ago, the Glossopteris plant became a common sight throughout Gondwana. This was a super continent that included regions known today as Africa, Antarctica, Australia, India and South America.

The presence of Glossopteris was used as supporting evidence for the revolutionary theory of “continental drift” during the mid 20th century. They literally reveal how the world we recognise today took shape.

Glossopteris was easy to recognise because of its distinctive leaves; the name means “tongue-fern” in Greek, because of its shape. Fossil evidence suggests that the plants probably grew in diverse habitats and came in different forms. These ranged from short shrubs to trees as tall as a five-story building.

Scientists suggest that at least some of these plants were deciduous because their leaves are often found preserved in thick mats thought to be the result of seasonal shedding. At that point, they became not only important for understanding our history: they started contributing to fuels and materials that are still used today.

Power plants

Dead material from these plants accumulated in swamp environments, was buried, and over time formed South Africa’s vast coal reserves.

Under normal conditions, when plants die or shed their leaves these fall to the ground and decompose. Under special environmental conditions – such as those that occurred in the vast Permian swamps of Gondwana (which were a bit like today’s mangrove swamps) – the process differs. Once Glossopteris shed their leaves, the plant material accumulated in acidic water with high levels of tannins and low oxygen concentrations.

This re****ed the activity of the bacteria, fungi and other organisms that would otherwise lead to decomposition. Over time layers of mud, silt and sand washed into the swamp and buried the waterlogged peat layers. Millions of years passed. During this period the mud, silt, sand and the encased plant material experienced great pressure and high temperatures. It was compressed and changed into rock, and underwent various chemical changes.

The result? Coal seams. This is why coal is referred to as a fossil fuel. It is also a reminder that coal is finite.

Apart from being the major source of fuel in the production of South Africa’s electricity, Glossopteris influences our lives in many ways. The carbon atoms harvested from the air as carbon dioxide by these trees during the process of photosynthesis, hundreds of millions of years ago, can also be found in petrol, waxes, plastics, and a host of other products used in everyday life.

New finds
South Africa has a huge potential for new fossil discoveries, with vast territories still waiting to be explored, yet very few researchers are studying fossil plants and insects.

We are part of a small group of researchers based at the Albany Museum in Grahamstown in the Eastern Cape province who are determined to change this by shedding more light on Glossopteris and fossil plants in general.

At the moment we’re working on a few small road cuttings near a Northern Cape town called Sutherland. This is revealing a depth of knowledge about Permian ecosystems that has not been seen before in South Africa, and is very rare on a global scale.

New discoveries are not only about bringing a wonderful piece of the country’s heritage to light. This work is also opening up new scientific fields and opportunities for skills development that the country desperately needs.

12/01/2022

12/01/2022