Prairie Study Documents Catastrophic Loss Of Species

September 12, 1996


CONTACT: Thomas J. Givnish, (608) 262-5718; Mark K. Leach, (608) 263-7344

(Editor's note: Color image of Curtis Prairie is available upon request.)


Surveying the few remaining patches of what was once a vast prairie, scientists have found disturbing evidence that prairie plant species are disappearing at a pace that will all but erase native prairies from the landscape within decades.

The study, conducted by University of Wisconsin-Madison biologists Mark K. Leach and Thomas J. Givnish and to be published Sept. 13 in the journal Science, is important because it provides grim evidence that fragmentation of the landscape by human activities and the disruption of natural processes like fire have dire consequences for prairies and many other ecosystems worldwide.

Leach, an ecologist at the UW-Madison Arboretum, and Givnish, a professor of botany, document a staggering decline in the diversity of native prairie plants in 54 small and scattered tracts of remaining native Wisconsin prairie that were first surveyed 50 years ago by pioneering ecologist John Curtis.

Revisiting old railroad rights of way, country cemeteries and untillable slopes that harbor the last remaining patches of a vast prairie landscape that once covered nearly 2 million acres in prehistoric southern Wisconsin, the UW-Madison scientists found that between 8 and 60 percent of plant species were lost from individual tracts over the last 30 to 50 years.

"It is very serious," says Givnish, a UW- Madison professor of botany. "The rate of loss is catastrophic. We're talking about losing one-half of all species in a remnant prairie in less than a century under the best of circumstances."

In particular, the Wisconsin scientists found that short, small-seeded and nitrogen- fixing plants such as legumes experienced the heaviest losses.

"Short plants are particularly susceptible because they can be shaded out by taller species," says Givnish, "and small-seeded plants have a disadvantage in getting started under conditions of dense growth," a circumstance accommodated by the absence of fire.

"Fire suppression also puts legumes at risk by allowing nitrogen to build up and thereby eliminating the competitive advantage of nitrogen fixers," according to Givnish.

According to Leach, presettlement Wisconsin, and much of prehistoric America, was a fire-swept landscape, and plants and animals in widely diverse ecosystems adapted to regimes of intermittent wildfire.

As the North American landscape developed over the past 200 years and as fires were suppressed or impeded by agriculture and other barriers, trees and non-native plants supplanted those adapted to fire.

"Fire was an important part of many North American ecosystems," says Leach, and many patches of prairie survived into this century only with the help of accidental fires ignited by steam locomotives, the burning of untillable slopes by farmers, and the infrequent maintenance of old country cemeteries.

But with the disappearance of the steam locomotive and the continued and accelerated development of the rural landscape, even those remaining patches are being lost. Of the more than 200 sites originally identified by Curtis in the 1930s and 1940s, many were degraded, and some were outright obliterated by the effects of pesticides and development.

Without protection, restoring new areas and appropriate management, including prescribed burns, those remaining patches will also be lost, says Leach.

"As these habitats become less common, there are fewer species that are going to persist," says Leach. And without fire, many species "are just going to be gone. We won't have them anymore."
_ Terry Devitt, (608) 262-8282,

University of Wisconsin-Madison

Related Plant Species Articles from Brightsurf:

German researchers compile world's largest inventory of known plant species
Researchers at Leipzig University and the German Centre for Integrative Biodiversity Research (iDiv) have compiled the world's most comprehensive list of known plant species.

Evolution in action: New Plant species in the Swiss Alps
A new plant species named Cardamine insueta appeared in the region of Urnerboden in the Swiss alps, after the land has changed from forest to grassland over the last 150 years.

Invasional meltdown in multi-species plant communities
New research led by University of Konstanz ecologists reveals invasional meltdown in multi-species plant communities and identifies the soil microbiome as a major driver of invasion success.

Study shows Latin America twice as rich in plant species as tropical Africa
Latin America is more than twice as rich in plant species as tropical Africa and is home to a third of the world's biodiversity, a new paper published today in Science Advances confirms.

Plant size and habitat traits influence cycad susceptibility to invasive species
A long-term study on cycads in Guam has revealed how rapidly invasive species devastated the native Cycas micronesica species and the key factors that have influenced the plant's mortality.

About 94 per cent of wild bee and native plant species networks lost, York study finds
Climate change and an increase in disturbed bee habitats from expanding agriculture and development in northeastern North America over the last 30 years are likely responsible for a 94 per cent loss of plant-pollinator networks, York University researchers found.

Australian fossil reveals new plant species
Fresh examination of an Australian fossil -- believed to be among the earliest plants on Earth -- has revealed evidence of a new plant species that existed in Australia more than 359 Million years ago.

Study: One-third of plant and animal species could be gone in 50 years
University of Arizona researchers studied recent extinctions from climate change to estimate the loss of plant and animal species by 2070.

Scientists challenge notion of binary sexuality with naming of new plant species
A collaborative team of scientists from the US and Australia has named a new plant species from the remote Outback.

Plant lineage points to different evolutionary playbook for temperate species
An ancient, cosmopolitan lineage of plants is shaking up scientists' understanding of how quickly species evolve in temperate ecosystems and why.

Read More: Plant Species News and Plant Species Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to