You are here

Warmer Temperatures From Climate Change Likely To Change Vegetative Landscape In Southwestern National Parks


In the drier Arizona upland plant communities some species will likely decline with forecasted climate change (such as foothill paloverde, ocotillo and creosote bush) while cacti may well increase in abundance and range. NPS photo by Sarah Studd.

While desert-thriving vegetation commonly is thought to love heat, too much heat and reduced precipitation can doom them. A new study into the likely impacts of climate change says higher temperatures will recast the native plants we find in places such as Saguaro National Park and Organ Pipe Cactus National Monument.

The study, contained in the recent issue of Global Change Biology, says such iconic Sonoran Desert plants as velvet mesquite and ocotillo will decline as temperatures grow hotter, while other cacti should flourish.

"By carefully examining long-term records of how vegetation has responded to variability in numerous climate-related parameters, such as temperature, mean rainfall and aridity, scientists have been able to find the key to predicting the future for complex ecosystems," remarked U.S. Geological Survey Director Marcia McNutt. "This type of study is an essential first step in gaining insight to the world our children will be inheriting."

This research was conducted by a team of scientists from the U.S. Geological Survey and National Park Service. They took advantage of 100 years of plant monitoring results from Saguaro National Park, Organ Pipe Cactus National Monument, the Desert Laboratory, and the Santa Rita Experimental Range near Tucson, Ariz. The analysis used in the study identified the plant species susceptible to climate change by determining past relationships between climate and vegetation across sites.

"There is evidence that climate change is happening at regional to global scales with long-term effects, but plant ecological research is generally conducted in a very small area over a short period of time," said Seth Munson, a USGS scientist and lead author of the study.  "This work integrates the results from four of the longest-running vegetation monitoring sites in the world to provide a more complete picture of how the plant composition, structure and productivity of a desert ecosystem may change in the future."

The study identifies critical points along a climate gradient that cause a reduction in plant abundance.

For example, perennial grasses such as bush muhly and curly mesquite grass decreased when annual precipitation dipped below 15 inches -- this amount of water input may indicate a threshold that limits  perennial grass performance in the Sonoran Desert. 

A main goal of this study was to inform the management decisions of the Park Service and other land-management agencies in the Sonoran Desert. For example, the research shows that increases in aridity correspond to declines in white ratany, a shrub that provides food for the endangered desert tortoise, which is intensively being monitored by NPS, U.S. Fish and Wildlife Service, and Arizona Game and Fish. 

 "Understanding climate-vegetation dynamics is important to both short-term management decisions and long-term planning for projected climate change," said John Gross, an ecologist with the Park Service's Inventory and Monitoring Program. "A knowledge of vegetation dynamics is essential to conducting ecological vulnerability assessments and subsequent planning for climate adaptation in our parks," he added. 


Guess again... there may be some human driven changes to the climate, but global warming has been established to be a POLITICAL issue rather than a scientific one.  There was a report released a couple weeks ago from the agency that does the official global temperature monitoring.  There have been 15 years in a row wihtout any increase in global temperature.  They have gone on to say that their computer models DO still feel that the global temperature will rise over the next couple of years.  However they also add that they have been making that same perdiction for 10 years and have been WRONG all of those years.  There is now a genuine effort by that agency to evealuate the cmputer model that they are using to determine if it is accurate.  That computer model in question is the same one used to justify most global warming arguments.  They also acknowledge that many of the computer models developed by other agencies are predicting slight cooling over the next few years.
At this time, we really don't know much, and all possibilites are on the table.  The only thing right now that looks likely is that the theories on global warming are looking less and less probable.  Global warming is not now, and has never been scientific fact, only a working theory.

Anon, there seem to be some contradictory and very shaky arguments in your post.  You say that warming is not a scientific fact, but only a working theory.  True.

Yet a little earlier you make a hard claim that it has somehow been "established" that it is a "political" and not scientific issue.  "Established" how and by whom?

You repeatedly refer to "the agency" and "they" who are your sources for the information you purport to be quoting here.  How about some documentation and specifics?  Who are "they?"  And which "the agency" do "they" represent?

In any discussion of science, it's necessary to use good science.  Good science depends upon documentation and not vague claims that cannot be supported.

Lee, this quote seems to have threads through many of the conversations/posts on here as it does with this one.  It was submitted by Roadranger.

"Regarding the environmental movement. When it began in the early '60s the movement had about it an altruistic core that was embraced pretty much across the board by the political spectrum. Today, the movement has been captured by the anti-capitalist, unhinged left that has been adrift since the collapse of the Soviet Union. Although the NPS seems to have avoided open identification with the current movement, many of its employees are proud to identify themselves as part of the leftist elite and poised to ridicule those who are not in lockstep with their beliefs. This group needs to understand that there are millions of centrists and conservative environmental advocates - individual and corporate - who have supported the NPS mission in the past and will continue to do so. Such an acknowledgement would be good for the health of the NPS and help it survive the political swings from left to right and back again that are likely in our future."

There's such a volume of political BS that is deceptive (being kind) reflecting the stridency of ideology that it really is a concerning time.  I am a bit encouraged by the Roadranger's way of putting it.

"In any discussion of science, it's necessary to use good science."
Oh "good science" like that from those that want to "hide the decline".  LOL
But yes, anon, be more specific with your sources please.  Although I suspect he is referring to the BEST study.

 If Global warming is "BS" how do you explain the rapid melting of the majority of the earths glaciers?? Forget about 'studies" --just look at the pictures 100 yrs ago and compare to what is now???

University Arizona Press
The Changing Mile Revisited
An Ecological Study of Vegetation Change with Time in the Lower Mile of an Arid and Semiarid Region
By [color=#0000ff]Robert H. Webb[/color]; [color=#0000ff]Raymond M. Turner[/color]; [color=#0000ff]Janice E. Bowers[/color]; [color=#0000ff]James Rodney Hastings[/color]
334 pp. / 9.00 in x 12.00 in / 2003
Cloth (978-0-8165-2306-1) [[color=#0000ff]s[/color]]
Cloth ($75.00)  
 The Changing Mile, originally published in 1965, was a benchmark in ecological studies, demonstrating the prevalence of change in a seemingly changeless place. Photographs made throughout the Sonoran
An invaluable reference and a benchmark in ecological studies, but it also offers a fascinating portrait of this region and a unique view into our history. —Taxon The photo-comparisons speak for themselves, and they whisper the question of 'why?' . . . Revisited will be a welcome addition to the coffee tables and bookshelves of Southwestern scientists. It is well worth the wait of four decades. —Journal of the Arizona-Nevada Academy of Science Desert region in the late 1800s and early 1900s were juxtaposed with photographs of the same locations taken many decades later. The nearly one hundred pairs of images revealed that climate has played a strong role in initiating many changes in the region. This new book updates the classic by adding recent photographs to the original pairs, providing another three decades of data and showing even more clearly the extent of change across the landscape. During these same three decades, abundant information about climatic variability, land use, and plant ecology has accumulated, making it possible to determine causes of change with more confidence. Using nearly two hundred additional triplicate sets of unpublished photographs, The Changing Mile Revisited utilizes repeat photographs selected from almost three hundred stations located in southern Arizona, in the Pinacate region of Mexico, and along the coast of the Gulf of California. Coarse photogrammetric analysis of this enlarged photographic set shows the varied response of the region's major plant species to the forces of change. The images show vegetation across the entire region at sites ranging in elevation from sea level to a mile above sea level. Some sites are truly arid, while others are located above the desert in grassland and woodland. Common names are used for most plants and animals (with Latin equivalents in endnotes) to make the book more accessible to non-technical readers. The original Changing Mile was based upon a unique set of data that allowed the authors to evaluate the extent and magnitude of vegetation change in a large geographic region. By extending the original landmark study, The Changing Mile Revisited will remain an indispensable reference for all concerned with the fragile desert environment.

EC -- with respect, I don't understand the second sentence of your post.  Will you explain it for my poor old thinker?

Then I'll know whether I should purr or growl.

To the climate change deniers:


I have a direct view of a glacier through my livingroom window. C'mon up here to Alaska and watch the ice hasten in it's receeding.

It isn't 'just political' when you see it unfold in front of you.

National Parks Traveler's Essential Park Guide

Recent Forum Comments