Add Wolves, Subtract Elk = More Berries for Bears!

First, a little natural history background information.

(1938 park poster, via Wikimedia)

Yellowstone was declared as the first National Park In March 1872, signed into law by President Ulysses S. Grant, an act that created one of today’s most-visited U.S. parks.  Although a national park, poaching decimated the ungulate populations (e.g., elk, bison) and carnivores.  In 1883, the Secretary of the Interior banned hunting of most animals in National Parks, excluding larger carnivores and omnivores.

Unregulated hunting of ungulates in Yellowstone was largely curtailed by 1886.  However, increased pressure from neighboring ranchers and citizens resulted in the Grey Wolf (Canis lupus) being extirpated from Yellowstone.  The last official killing within the park occurred in 1926.

(Gray Wolf, Fish and Wildlife Service)

Fast forward to 1967.  Within the first year of the Endanger Species Preservation Act, the Gray Wolf classified as endangered.  Around this time, the importance of wolves as a predator was becoming more apparent.  Cultural views soon followed the scientific findings that Gray Wolves, an apex predator, play a significant role in shaping the communities in which they live.

(Bull Elk By Mongo, via Wikimedia Commons.)

1995.  After decades of absence, and 20 years of planning, wildlife biologists introduced 14 wolves to Yellowstone National Park.  Wolves were observed to feed primarily on elk (Cervus elaphus).  The Yellowstone Nation Park Gray Wolf populations seemed stable following another addition of 17 wolves in 1996.

Now on to the “neat news”…

Ripple et al. just published an article in the Journal of Animal Ecology examining the hypothesized tropic cascade resulting from the absence, and then reintroduction of Gray Wolves in Yellowstone. 

In a nutshell: 

(Grizzly bear, via Wikimedia)

The presence of wolves has indirectly caused in increase abundance of berries in the diet affected the of Grizzly bears (Ursus arctos) in Yellowstone National park, which in the result of reduced herbivory of and competition for berries by wolf’s preferred food, elk.

Without wolves, park populations of elk were, on average, 12 elk square kilometer, and Elk populations declined following wolf reintroduction, to approximately one elk per square kilometer.  Lower Elk population densities have resulted in increased woody plant recruitment, particularly berry-producing shrubs.  Ripple et al. (2013) demonstrate that this shift in plant community composition (Ripple and Beschta, 2012) also resulted in a shift in Grizzly Bear feeding behavior – an increase in berry consumption. 

Figure 6 (Ripple and Beschta, 2004) illustrating creek plant community composition in 1996 (left),
and the same location in 2002 (right), following wolf population establishment.  (Image via Lycographos)

Original article and other works cited:

Ripple, William J., Beschta, Robert L., Fortin, Jennifer K., Robbins, Charles T. 2013. Trophic cascades from wolves to grizzly bears in Yellowstone. Journal of Animal Ecology. DOI 10.1111/1365-2656.12123.

William J. Ripple and Robert L. Beschta. 2012. Beschta. Trophic cascades in Yellowstone: The first 15 years after wolf reintroduction. Biological Conservation. 145(1):205-213. http://dx.doi.org/10.1016/j.biocon.2011.11.005.

William J. Ripple and Robert L. Beschta. 2004. Wolves and the Ecology of Fear: Can Predation Risk Structure Ecosystems? BioScience. 54(8):755-766. DOI: 10.1641/0006-3568(2004)054[0755:WATEOF]2.0.CO;2

Background information sources:  Gray Wolf Endangered Species Profile (FWS); Yellowstone National Park webpage and pages therein; Yellowstone Wolf Project (Nat'l Park Service. 1996. YCR-NR-97-4).

National Moth Week - July 20-28

National Moth week has begun!

This international celebration and appreciation of moths has expanded rapidly since it began in central New Jersey in 2011.  

Local NMW events are catching the attention of:

• The Star Ledger (video below) 
• Governor Christie!

  

FREE local events hosted by NMW founders

Wednesday, July 24, 8:30 pm to 11:00 pm

Hosts: Elena Tartaglia, Ph.D. Rutgers University and Matt Sichel of Stockton College

Location: Pinelands Preservation Alliance, 17 Pemberton Road, Southampton Township

Details:  Event Link.

Thursday, July 25, 8:30 pm to midnight

Host: Jamie Cromartie, Ph.D. of Stockton College of New jersey

Location: Arts & Science Building, Stockton College

Details:  Event Link.

Thursday, July 25, 8:30 pm to ?
Hosts: experts from the American Entomological Society

Location: Chatsworth Lake entrance on Route 532, Franklin Parker Preserve, Chatsworth

Details:  Event Link.

Friday, July 26, 8:00 pm to ?
Hosts: Bernie Knaupp and other NMW associates

Location: 120 Whites Bogs Road, Browns Mills

Details:  Event Link.

Can’t make it to one of the above events?

Visit this neat blog, Mercury Vapor, Moths & Me, featuring photographs (image right) and identification information for moths found in Middlesex County, New Jersey.

Not in New Jersey?  Check out the below map for events near you!

Map Key: Green markers show public events – Blue markers show (mostly) private events  – Red markers link to country maps

View 2013 NMW USA Events in a larger map.  Click here for an international list of locations.

Attack of the killer ladybird!

(Image via Wikimedia Commons)

No, unfortunately, there is not a Godzilla equivalent for ladybird beetles, but there is this funny cartoon.  

Now, on to the science!

 

The Science

Many of us are familiar with ladybugs.  These neat insects, more correctly termed ladybird beetles because they are not true bugs, belong to the insect family Coccinellidae.  This time of year gardeners are especially appreciative of ladybirds as the majority of species consume aphids and other pests, which would otherwise damage beloved garden plants.  However, not all ladybirds are native to the U.S.; Europe also has its fair share of nonnative ladybugs.  Several of these nonnative ladybirds are invasive – outcompeting their native counter parts. 

Asian harlequin ladybird
(Wikimedia Commons)

A recent scientific study published in the journal Science (Vilcinskas et al. 2013) indicates that the Asian harlequin ladybirds (Harmonia axyridis), originally introduced to Europe (and North America) for pest control, are now threatening the survival of indigenous ladybug species.   

Vilcinskas et al.’s found that the Asia ladybird is a carrier of inactive spores produced by an obligate parasitic microsporidia.  Although the parasite does not harm Asian ladybird, it has proven lethal to the native, Seven spot ladybird (Coccinella septempunctata).

 

Seven spot ladybird
(Wikimedia Commons)

Original publication citation:

Vilcinskas A, Stoecker K, Schmidtberg H, Röhrich CR, Vogel H. 2013. Invasive harlequin ladybird carries biological weapons against native competitors.  Science. 340(6134): 862-3.

If you are unable to access the original article, a summary article by R. Williams may be found here at The Scientist.

 

Learn More About Ladybirds & Ladybird Conservation Efforts

Spotted lady beetle on a sedge
inflorescence (By L. Shappell)

First, visit The Lost Ladybug Project - resources therein include:

• Tools for ladybug identification, including this one-page field guide.  
• I used this field guide to ID the ladybird pictured in the adjacent photo; it is an indigenous Spotted lady beetle foraging on a sedge (Carex sp.) at one of my field research sites!
• Tips on how to find and photograph ladybirds
• Instructions on how to share your photos and contribute to their citizen science ladybird surveys

To top if off, ladybirds can walk underwater!

Air packets are trapped in the tiny hairs on their feet.  When the air pockets are combined with a polymer secreted into the hairs they can stay grounded through the force of adhesion.  Learn more in this Nature News article.

(Okay, now I'm thinking Ladybird takes over Atlantis, Godzilla-style!)