How to fight Insectageddon with a garden of native plants

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A giant swallowtail butterfly feeds from the flower of an alternate-leaved dogwood.
(Nina Zitani), Author provided

by Nina M. Zitani, Western University

People across North America love to garden, yet the vast majority of garden plants are non-native species.

Day-lilies, peonies, roses, chrysanthemums and butterfly bushes, just to name a few, are all non-natives. They evolved in far-away places such as Europe and Asia and people transported them to North America.

With Insectageddon — the great insect die-off — upon us, it’s time to rethink our gardens.

Habitat destruction is the primary cause of the decline in biodiversity. Around the world, wildlife habitat has been destroyed by a variety of human activities such as residential and commercial development, agriculture and mining operations.

But gardeners can help to reverse the trend in biodiversity loss by creating backyard habitat, and native plants are the key.

Gardening with native plants has a long history in North America, but it remains under the radar of mainstream gardening. It’s time we embraced our native plants and the biodiversity that comes with them.

Our feathered — and furry — friends will thank us for it.

And if you’re an insect hater, now might be a good time to rethink that attitude.

Many insects are picky eaters

It was hot and steamy in the Costa Rican tropical forest. I was looking for caterpillars — the cute, wiggly, multi-legged and often furry larval stages of moths and butterflies.

As a graduate student at the University of Wyoming, I wasn’t studying caterpillars per se, but looking for new insect species. My job was to search for parasitoid wasps — minute, non-stinging wasps that spend their immature stage living inside caterpillars.

I collected the caterpillars in plastic bags along with the fresh green leaves they were feeding on, and brought them back to the field station for rearing.

But before I knew it, I was headed back into the forest. The caterpillars were leaf-eating machines and needed fresh leaves often. But I couldn’t just go into the forest and grab some leaves. I had to find the exact plant species the caterpillars were eating, or they would starve and die.

And that’s how I learned that caterpillars, most of them anyway, are picky eaters.

The caterpillar of the giant swallowtail butterfly feeds on the leaves of hoptree.
(Nina Zitani), Author provided

Neatly tucked away in the scientific literature, you’ll find the fascinating story of plant-animal co-evolution that began millions of years ago during the Mesozoic Era. There are many outcomes of that co-evolution, such as pollination, seed dispersal and the close relationship caterpillars (and other plant-feeders) have with their food plants.

Today, flowering plants produce toxic chemicals in their leaves to deter animals from eating them. But some animals, namely caterpillars, have adapted to eat the plant leaves — toxins and all.

So if you’re interested in creating wildlife habitat in your backyard, then you’re going to need the favourite food plants of insects. Insects will then thrive in your garden — as will the many larger animals that depend on insects for food.

What is a native plant?

To better understand the concept of a native species, consider common milkweed and its relative, the dog-strangling vine.

Both are members of the milkweed family and found today in North America. Common milkweed is a native plant — it evolved in North America thousands of years ago, along with some other animals, including the monarch butterfly and the milkweed tussock moth. Today it is vital to the survival of those species.

But dog-strangling vine is a non-native plant from Europe that was introduced to North America by settlers in the 1800s. Monarch caterpillars and other native milkweed specialists that hatch on dog-strangling vine die because they can’t eat it.

To make matters worse, dog-strangling vine has become an invasive species, forming dense colonies that displace native plants and their associated animals, contributing to biodiversity loss.

(No, it does not strangle dogs, by the way.)

Planting for the birds

Birds (and other larger animals) depend on bugs. “Nearly all terrestrial birds rear their young on insects, not seeds or berries,” writes Doug Tallamy in his book Bringing Nature Home.

A simple way to think of it is this: Native plants maintain natural ecosystem food webs, whereas non-native plants don’t. Native plants will attract and support healthy insect populations in your garden, which will provide essential food for birds and other animals.

There are thousands of native, or wild, North American pollinator species, including approximately 4,000 native bees and about 700 native butterflies, not to mention other pollinating insects such as moths, flies and beetles.

The leaves of native plants provide the food for caterpillars. The flowers of native plants provide food — pollen and nectar — for the pollinators.

When we consider the entire life cycle of insects, the essential role of native plants becomes clear.

A caterpillar and a bumblebee on native Carolina rose.
(Nina Zitani), Author provided

And let’s not forget the non-native honey bee, one of the few domesticated insect species. Although the honey bee is not wildlife, it does pollinate some crops and produces honey. It too will find plenty of food in a native plant garden.

Small gardens, big impact

My family kicked off our native garden by planting a single common milkweed plant into our tiny urban garden. The following summer it bloomed, and when a monarch butterfly landed on it, we were hooked.

When we moved to a larger property years later, we decided to create a monumental garden full of biodiversity.

We travelled for hours to purchase plants from nurseries that specialized in locally sourced native plants. Over several years, we planted more than 100 native species, including two kinds of milkweed, nannyberry, daisies of all sorts, multiple kinds of roses, dogwoods, elderberry and more.

We also planted hoptree (Ptelea trifoliata, a Citrus relative), the food plant for the caterpillar of the giant swallowtail, North America’s largest butterfly.

A monarch butterfly gathers nectar on a native daisy commonly called cup plant.
(Nina Zitani)

You don’t need to have a huge garden to support wildlife. Start small, and plant just one native plant. Butterfly milkweed is a great choice, but there are thousands of native species to choose from. Starting small is better than not starting at all.

It’s easy to get started. The Nature Conservancy of Canada publishes the “Native Gardening 101” guide. The USDA Plants Database has species range maps for all of North America and allows you to search on common names of plants such as butterfly milkweed. The Ontario Invasive Plant Council’s “Grow Me Instead” guide includes many native plant options.

Nature Needs Half is a growing conservation movement. A reasonable end goal might be to devote half of your garden to native plants.

A year after we planted the hoptree, we spotted a giant swallowtail butterfly laying eggs on its leaves. Several days later we found the caterpillars eating the leaves, and we celebrated.

The ConversationBut not for long — we had gardening to do!

Nina M. Zitani, Assistant Professor of Biology, part-time, Western University

This article was originally published on The Conversation. Read the original article.

Scientist at work: I’ve dived in hundreds of underwater caves hunting for new forms of life

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Author Tom Iliffe leads scientists on a cave dive.
Jill Heinerth , CC BY-ND

Tom Iliffe, Texas A&M University

Maybe when you picture a university professor doing research it involves test tubes and beakers, or perhaps poring over musty manuscripts in a dimly lit library, or maybe going out into the field to examine new crop-growing techniques or animal-breeding methods. All of it’s good, solid research and I commend them all.

Then there is what I do – cave diving. To study the biology and ecology of coastal, saltwater caves and the marine fauna that inhabit them, my cave diving partners and I head underground and underwater to explore these unique and challenging ecosystems. Often we go to places no other human has been. While the peaks of the tallest mountains can be viewed from an airplane or the depths of the sea mapped with sonar, caves can only be explored firsthand.

Around the globe, from Australia to the Mediterranean, from Hawaii to the Bahamas and throughout the Caribbean, I have explored more than 1,500 such underwater caves over the last 40 years. The experience can be breathtaking. When you are down 60 to 100 feet in a cave that has zero light and is 20 miles long, you never know what you are about to see as you turn the next corner.

The remipede Cryptocorynetes elmorei from Eleuthera, Bahamas. Remipedes are only found in deeper saltwater layers from caves on opposite sides of the Atlantic and from the Indian Ocean coast of Western Australia.
Tom Iliffe, CC BY-ND

My primary focus is searching for new forms of life – mostly white, eyeless crustaceans – that are specifically adapted to this totally dark, food-poor environment. Cave diving is an essential tool in our investigations since the caves I’m interested are filled with water: typically a layer of fresh or brackish water on the surface and then saltwater at depths of 10 to 20 meters or more.

There’s no other way to access these unexplored areas than to strap on your scuba tanks and jump in.

Scientific research as extreme sport

The list of what can go wrong in a cave dive could fill your event planner.

Equipment or light failure, leaking scuba tanks, broken guide lines, getting lost, cave collapse, stirred up silt resulting in zero visibility, poisonous gas mixtures – you get the idea.

It’s fieldwork that can be a matter of life or death. I have had some close calls over the years, and sadly, have lost several good friends and researchers in cave accidents.

Tom Iliffe preparing for a side mount dive at Cliff Pool, Bermuda. Rather than carrying tanks on his back as in conventional scuba, a tank is clipped off under each arm, allowing him to pass through low sections in a cave where it would otherwise be impossible to go.
Gil Nolan, CC BY-ND

To put it mildly, underwater caves can be very hostile and unforgiving. One such cave – the Devil’s system in north-central Florida – has claimed at least 14 lives in the last 30 years, and there are other examples elsewhere in Florida and in Mexico.

Most of the time, human error is to blame, when divers don’t follow the rules they should or lack essential training and experience in cave diving.

My family has gotten used to the idea that what I do is not always a walk in the park. They know that since I’m 69, I stress safety, being physically and mentally prepared, and that I religiously abide by the cardinal rule of cave diving – that you never ever dive alone. My colleagues and I usually go into a cave with teams of two to three divers and constantly look after each other to see if there is anything going wrong during our dives, which usually last about 90 minutes, but can be as long as three hours or more.

Tom Iliffe diving with his Megalodon closed-circuit rebreather in a lava tube cave in the Canary Islands.
Jill Heinerth, CC BY-ND

Death-defying dives pay off in discoveries

It’s not just new species we are discovering, but also higher groups of animals including a new class, orders, families and genera, previously unknown from any other habitat on the planet. Some of our newfound animals have close relatives living in similar caves on opposite margins of the Atlantic Ocean or even the far side of the Earth (such as the Bahamas versus Western Australia).

While most of these caves are formed in limestone, they can also include seawater-flooded lava tubes created by volcanic eruptions. Amazingly, similar types of animals inhabit both.

In the deserts of West Texas, our team discovered and explored the deepest underwater cave in the U.S., reaching a depth of 462 feet.

The graduate students in my lab work on a diverse group of questions. They’re uncovering the nature of chemosynthetic processes in caves – how microorganisms use energy from chemical bonds, rather than light energy as in photosynthesis, to produce organic matter – and their significance to the cave food web.

Other students are examining records of Ice Age sea level history held in cave sediments, as well as the presence of tree roots penetrating into underwater caves and their importance to the overlying tropical forest. We’re finding evidence that sister species of cave animals on opposite shores of the Atlantic separated from one another about 110 million years ago as tectonic plate movements initiated the opening of the Atlantic, as well as determining how environmental and ecological factors affect the abundance and diversity of animals in saltwater caves.

Our research has significant implications, especially concerning endangered species and environmental protection. Since many cave animals occur only in a single cave and nowhere else on Earth, pollution or destruction of caves can result in species extinctions. Unfortunately, the creation of many protected areas and nature reserves failed to take cave species into account.

The remipede Godzillius robustus from Abaco, Bahamas. Note the darker shaded venom-injecting fangs on the first pair of appendages.
Tom Iliffe, CC BY-ND

Some discoveries can be completely unanticipated. For example, when we sequenced DNA from a variety of arthropods, including crustaceans and insects, the data strongly support a sister group relationship between hexapods (the insects) and remipedes, a small and enigmatic group of marine crustaceans exclusively found in underwater caves. This places the remipedes in a pivotal position to understanding the evolution of crustaceans and insects.

The author on a cave dive.
Jill Heinerth, CC BY-ND

Even at this stage of my life, to me the risks attendant to my cave diving research are worth it. It’s like the Star Trek mantra come true – to boldly go where no man has gone before. The chance to discover new forms of marine life, to view never-before-seen underwater formations, vast chambers, endless tunnels and deep chasms, to swim in some of the bluest and purest water on Earth – I will take that sort of research and its challenges any day.

The ConversationYes, it can give new meaning to the old line about “publish or perish” in academia. But I love it, and I will tell you with all honesty, I can’t wait until my next trip.

Tom Iliffe, Professor of Marine Biology, Texas A&M University

This article was originally published on The Conversation. Read the original article.

How to embrace urban living, but avoid an apocalypse

 

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The future of cities?
Paul Jones/Northumbria, Author provided

Paul Jones, Northumbria University, Newcastle

Cities – we are repeatedly told – are the future. Governments and global corporations seek to increase productivity by accelerating urban growth, while more and more citizens migrate to cities, in search of a better life. Indeed, the Chinese government recently unveiled plans to construct a city three times the size of New York, calling it a “strategy crucial for a millennium to come”.

Yet as it stands, visions of our urban future are bleak.

By 2050, it is predicted that up to six billion inhabitants will live in urban areas – more than two thirds of the world’s population. There could be as many as 30 cities with populations exceeding 10m, and massive urban areas may merge to form megacities, resulting in urban populations exceeding 50m.

According to Mike Davis, author of Planet of Slums, approaching two billion of the world’s inhabitants will live in slums, scratching out an existence without access to the basic services necessary for life. Another four billion will live severely compromised lives within urban sprawl, left to fight for resources as city governments fail to cope with the rapid influx of people.

A dim prospect.
Tokyoform/Flickr, CC BY-NC-ND

Social services and health facilities will break down. Human catastrophes such as starvation and the spread of disease will result from unsanitary conditions and high population density. The megacities of the future will have weak and unsustainable local economies, that will negatively affect citizens’ lives in myriad ways.

Wealth will not provide immunity from these issues. Pollution will rise exponentially, with toxic smog regularly enveloping entire cities. This will inevitably lead to a rise in respiratory diseases, which are already emerging as one of the three major health risks to the modern population. Bad air quality will be made worse by the urban heat island effect, as parks and rural hinterlands are built over to house the influx of people.

Nature will struggle to gain a foothold in the future city, with rural land predicted to shrink by 30% to accommodate urban expansion. The lack of countryside and green space will ultimately contribute to the sixth recorded mass extinction of animal and plant species.

A brighter future

But there is a way to avert this apocalyptic vision. Efforts to control the rapid and chaotic expansion of cities must go hand in hand with tackling the global environmental crisis, brought about by climate change. Governments, however, have proved unwilling or unable to reconcile the interests of global corporations with those of everyday people and the environment; this can be seen through their support of projects such as mining the Alberta Sands and oil operations in the Niger Delta.

Mining Alberta’s tar sands.
Kris Krug/Flickr, CC BY-NC-SA

As such, any alternative to this bleak urban future will require a radical shift in governance and economic philosophy. Scholars argue that society’s economic aim should be the sustainable production and fair distribution of wealth – rather than the maximisation of profit. Devolving wealth and power will help to build robust local economies and strong communities, which can mitigate the pressures of global urbanisation.

These changes should also be manifest in the physical structure and form of urban communities, with compact, densely populated, sustainable and self-governing community developments, as opposed to laissez-faire urban sprawl. In alternative future cities, urban blocks will support all the immediate needs of their inhabitants; from healthcare to housing, education, food production, clean water and sanitation.

Welcome to the Organicity

A cut-through view of the Organicity.
Paul Jones/Northumbria, Author provided

To better understand what such a place might actually be like, David Dobereiner, Chris Brown and I created Organicity: an illustrated prototype for localised, autonomous, sustainable, urban community infrastructure. The Organicity is densely occupied, with residential, urban agriculture, retail, industry, commerce, education and health facilities stacked above each other, accommodating approximately 5,000 people per unit.

Automated industries and waste processing are located beneath the living zone, where there is no need for natural light. Each unit has a primary industry which trades with other neighbouring communities to generate income to support the infrastructure. Resources should be managed at a local level, with a higher level of responsibility than is currently shown by global corporations.

Nature and knowledge, side by side.
Paul Jones/Northumbria, Author provided

Protecting the environment and supporting a diverse range of wildlife would be a natural function of these new communities. Biodiversity could be promoted by green corridors, situated near education, health and office spaces so that children and workers can benefit from the proximity of a rich natural environment.

People power

Investing in local people through the provision of skills and education will add to the commercial viability of the community, as well as building cohesion, purpose and mutual respect. As the sociologist Jane Jacobs argued back in the 1970s, for cities to remain viable they should become the producers of resources, rather than insatiable consumers.

In the Organicity, each development will have the necessary expertise for the community to flourish, including doctors, architects, solicitors, dentists, as well as skilled and unskilled labour. This new urban model transforms city blocks into productive environments. For example, the development of urban farming would boost food production and prevent starvation, which would be an inevitable consequence of unimpeded urban growth.

Community greenhouses.
Paul Jones/Northumbria, Author provided

The developments will vary in scale, with the bigger ones housing hospitals and other community facilities that require specialist facilities. The prototype reinvents the concept of “terraced housing”: land is stepped backwards up a slope, forming true terraces, where rows of houses are arrayed to embrace the public plaza and allotment gardens.

Within these communities, it is essential that people work close to where they live, to reduce the impacts of transport: not only will this tackle pollution, it will also afford people more quality time with their families and local community.

Sharing communal resources – including machinery and cars – is an important principle of urban sustainability. Communal ownership of assets, including real estate and green space, is essential for this model to work. Renewable technologies could also be community-owned, which would help to break people’s dependency on fossil fuel.

The ConversationBy shifting from globalisation to localisation, and creating smaller, self-sufficient communities within sustainable developments, cities could regain their equilibrium. From where we stand today, the Organicity may sound like a Utopian dream. But if we’re to avoid an urban apocalypse, we’re going to need strong alternative visions, to change the way we imagine and plan for the cities of the future.

Paul Jones, Professor of Architecture, Northumbria University, Newcastle

This article was originally published on The Conversation. Read the original article.