An Arachnid Winterland: Australia's wolf spiders escape flood waters

The picture above, taken by Daniel Munoz for Reuters, depicts a tranquil winter farmland scene - a blanket of white snow gently covering the ground. Ah, a classic winter tableau.

Or is it?

If it's winter, why is there no snow on the hillside behind the trees? And if you could get closer, you would see that it's not snow at all.

It's spider webs.

In Australia, following heavy rains and flooding in New South Wales, thousands of residents had to move to find drier ground. In the city of Wagga Wagga, over 8,000 residents needed to evacuate. Someone, or something, else also needed to evacuate: thousands upon thousands of wolf spiders.

Wolf spiders reside in tunnels or burrows in the ground. They line their homes with a silky web that facilitates easy and quick movements within the tunnel. With the flooding, the spiders moved to higher ground and as the soil remains saturated, returning to a damp home was out of the question. So the spiders built their webs above ground - their new homes spread out across the Australian farmland, looking for all the world like a fresh layer of snow. That is until you get up close and see all the wolf spiders wandering about over the webs, patiently waiting for the ground to dry out so they can return to their normally solitary, hidden lifestyle.

Creepy.

The many webs actually represent failed attempts at "ballooning." Ballooning is where a small spider releases a long silky strand of web which catches the wind and suddenly the spider is airborne. An effective means of travel - or, in this case, escape from a threatening situation - for small lightweight spiders, but many of the spiders here in Wagga Wagga were too heavy and so the threads would accumulate. The sticky threads would also latch onto the extra moisture in the air, making the webs more visible

However, while they wait for better living conditions, the spiders also perform an important service. The residual floodwater became a massive breeding ground for mosquitoes and other insects. As wolf spiders feed primarily on insects, that meant there was food aplenty.

"The amount of mosquitoes around would be incredible because of all this water," said Taronga Zoo spider keeper Brett Finlayson told the Sydney Morning Herald. "The spiders don't pose any harm at all. They are doing us a favor. They are actually helping us out."

As the soil begins to return to normal, some spiders will return to living underground, some may move on, while others will unfortunately become prey to birds and other small predators. It is expected that by the warm, dry days of summer, the population will have returned to normal.

I don't mind spiders. In fact, I'll leave the magazine or newspaper unrolled and will give them plenty of leeway since I know they help keep other insect populations in check.

But I'm still itching a bit just thinking about Australia's homeless arachnids.

Source: Sydney Morning Herald

Australia's Queensland Floods: aftermath poses grave risks to coral reefs

Nature has an uncanny way of healing itself from its own natural disasters, like forest fires, hurricanes and wind storm damage, and even volcanoes. The damage can be devastating but, given sufficient time, nature recovers. Time is the key factor. Time to rejuvenate and time for it to prepare for the next calamity, many of which being cyclical.

But when events happen one right after another or are working in concert to weaken the ecosystem's ability to withstand a particularly powerful disaster, or if we add man-made factors into the mix, then nature can find itself in dire peril.

Such is the case following the heavy rains and flooding that have recently taken place in and around Queensland, Australia. The flood waters don't simply evaporate but, instead, continue to move towards open sea. Swollen rivers feed into the ocean and they bring along three elements that are dangerous to the coral reef systems, offshore and to the north, that make up Australia's famed Great Barrier Reef: fresh water, sediment, and fertilizers/herbicides.

When great quantities of fresh water are introduced into a coral reef, the corals suffer tremendously as they are strictly salt water creatures. As the fresh water moves further offshore, it blends with the salt water and so the negative effects of too much fresh water are primarily limited to reefs and islands relatively close to shore.

Sediment that fans out at the mouth of rivers can also block sunlight and cover the corals. These fine particles essentially choke the corals, preventing them from feeding effectively and, with the loss of sunlight, starving the symbiotic algae that grows within the coral's tissues. Through photosynthesis, the algae converts sunlight into organic energy for the coral's benefit. But, with floating sediment, that life-giving process is disrupted.

Perhaps the corals could withstand those abuses, but then we must add man's contribution: fertilizers and herbicides. Washed down from farmlands, these chemicals stimulate plant growth, in particular seaweed and algae. Both compete for space with the coral and typically the coral loses. Nature has a way of balancing the relationship between plants and corals so that both can coexist, but with the introduction of fertilizers and other plant stimulants, that balance is thrown off kilter. Corals are rather slow growing, whereas sea plants, particularly when chemically stimulated, are very fast growing. It becomes an aquatic land grab and the seaweeds and algae soon take over.

However, even with the added impact of man-made fertilizers, coral reef ecosystems could deal with these three factors were it not for the fact that they are continually being bombarded and weakened by other hazards. Climate and temperature change, acidification, pollution and disease - one hit after another can have a cumulative effect that can leave the coral reefs exposed and overwhelmed by the negative effects of a natural disaster like the one that occurred in Australia.

The Queensland flooding has been a recent event and researchers are only now beginning to see and monitor the residual effects of the floods working their way out to sea. Coral damage from flooding has happened before and the reefs were able to heal themselves within a decade. But life in the Great Barrier Reef is different now, more precarious and fragile.

"The problem is that all forms of disturbances, loads of sediments/nutrients/pesticides, as well as bleaching events from warming seawaters, more intense cyclones and more frequent outbreaks of coral predators such as the crown-of-thorns starfish, all increase in frequency and intensity," says Dr. Katharine Fabricius of the Australian Institute for Marine Science. "This gives the reefs often not enough time to recover before they get hit again."

Read about the effects of Australia's floods on BBC News.