Monique Keiran: Spreading fungus threatens B.C.’s bats

In mid-March, hikers in the mountains east of Seattle found a sick bat near a trail. They brought it to a local animal hospital. Two days later, the bat died.

Scientists have since confirmed that the bat, of the common species known as the little brown bat or Myotis lucifugus, had suffered from an advanced case of white-nose syndrome. The fungus-caused disease has decimated bat species across northeastern U.S. and eastern Canada.

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This is the first reported case of the disease in the Pacific region. Until now, the fungus’s westernmost incidence was Nebraska, more than 2,000 kilometres away.

The researchers say the level of infection found in the Washington bat suggests the fungus has been in the wilderness area east of Seattle for several years.

If that is the case, the broad range of the little brown bat throughout the region means this probably isn’t an isolated case.

The species’ range, the fungus’s possible well-established existence in the area and the proximity to Canada also mean that the disease might be about to enter B.C. — if it hasn’t already. Once that happens, the 16 bat species native to the province will likely suffer as terribly, as have bat species elsewhere.

First documented in North America in 2007 in eastern New York, white-nose syndrome is named for the white fuzz that grows on the faces and wings of infected hibernating bats. The disease rouses the bats repeatedly from hibernation, causing them to burn through their winter fat. Dehydrated and without food, the bats starve to death before spring.

With this recent discovery in Washington state, the disease is now found in 28 states and five provinces. It is estimated to have killed at least six million bats since 2007. The three most affected species, including the little brown bat, have experienced death rates of close to 100 per cent in some regions.

The implications for B.C.’s forests, gardens, farms, vineyards and orchards are enormous. Bats are nature’s insect control. They eat as much as their body weight in insects each summer and fall night, helping to control moth, beetle and mosquito populations.

A recent U.S. study projects bat losses due to white-nose syndrome could cost the agricultural industry up to $53 billion. The costs will come from crops lost to feeding insects and from additional costs to control insects chemically.

A B.C. study documented that bats can help dampen forest-pest outbreaks. The researcher estimated that, during an outbreak of western spruce budworm in the south–central Interior in the 2000s, bats ate about 140,000 moths per 10 square kilometres each growing season, as well as consumed large quantities of budworm caterpillars. Widespread budworm outbreaks in the Interior during the past two decades have left the forest industry and many forest-dependent communities increasingly vulnerable — especially in the wake of the recent mountain pine beetle epidemic.

Some hope for western bats exists in the form of a common North American bacterium. Laboratory and field trials indicate the bacteria inhibit the fungus, and helps some — not all — bats survive. However, the research is in early stages, and likely comes too late to help eastern bat populations. The researchers are racing against time and the fungus’s spread — the longer the fungus takes to get here, the better the odds for our bats.

Our incomplete knowledge of B.C.’s bats doesn’t help. Of the 16 species native to B.C., 11 are found on Vancouver Island. However, more than half of the species are red- or blue-listed, with populations declining or near to becoming endangered — in most cases, we don’t know why.

Wildlife Conservation Society Canada’s BatCaver program is helping to address the gaps. It brings scientists and cavers together to locate and inventory the underground roosts where overwintering bats can be found. Strict quarantine protocols help keep the caves fungus-free.

At a community level, the B.C. Community Bat Project Network raises awareness about bats and provides information to home and property owners. It also organizes residents in many B.C. regions to monitor local bat populations. The information will provide a baseline to compare future data to. In the Greater Victoria area, Habitat Acquisition Trust spearheads the program.

With information, interest and intense effort, B.C.’s bats might stand a chance.

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