Access by Shuttle Bus Only
Through October 27, 2014 all access to the most visited part of the park, Frijoles Canyon, will be via a mandatory shuttle bus from the nearby community of White Rock from 9 AM - 3 PM daily. Private cars may drive in before 9 AM or after 3 PM. More »
Science and Resource Management Blog
Working Through Science
In natural resource management, decisions and actions are, or at least should be, based on the best available science. Here we will highlight local examples of science and management collaborations and explore practical reasons why it doesn't always work according to theory.
We will focus on research done by people in or near Bandelier that has contributed to significant natural resource management decisions.
Watching Trees Grow
Have you ever tried to watch a tree grow? While we all know that trees do grow, measuring how much they grow can be a challenge. Imagine being asked to find out how much bigger or smaller, or taller or shorter, a tree becomes over the course of days, weeks, months, or years. How long might it take you to notice if a tree had changed in size? Such a study may sound as exciting as the old adage of "watching paint dry." However, by measuring the change in size of ponderosa pine and Douglas fir trees over time, ecologists working in Bandelier National Monument have gained valuable insights regarding both the inner workings of these trees and the fire histories of ponderosa pine forests in the Jemez Mountains.
As the tree expands or shrinks in circumference, the spring expands or contracts with it. We can visit the tree at any time, take a quick look at the ruler, and measure its current size down to the tenth of a millimeter! These measurements can be compared to measurements taken in the past to track how much the tree has grown or shrunk.
What We've Learned
We have made several informative findings based on these measurements. First, ponderosa pine can both increase (swell) or decrease (shrink) in circumference over time, much like a sponge can change size as it is soaked in water, allowed to dry, and then soaked again. Figure 3 shows the change in size of trees at the low-elevation site during 1992. During the growing season, trees shrank during drier times but quickly swelled following precipitation.
Figure 3 also documents tree growth is greatest in the early growing season, occurring before the arrival of the summer monsoons. It would follow that the amount of winter snowfall has a large influence on tree growth during the following growing season. Data from dendrobanded trees can also be used to look at patterns over longer time periods. Figure 4 displays the average basal area index (BAI) of ponderosa pine trees at each of the three sites since 1992. The BAI is a measure of tree size. Based on graphs such as these, it is relatively easy to pick out years when water was plentiful based on large increases in growth across all sites (e.g., 1992-1995) or drought years when water was scarce and trees shrank or hardly changed (e.g., 2002-2003), resulting in the death of some banded ponderosa pine and most mature , piñon pine.
We have learned that ponderosa pine trees at the highest elevation site consistently grow more each year than trees at the middle and lowest elevation sites, which grow at similar, slower rates. It is interesting to note that the mixed conifer forest at the high-elevation site appears to provide better growing conditions for ponderosa than the ponderosa pine forest at the middle-elevation site. This hints that ponderosa pine forests are not necessarily the best places for ponderosa pine to grow. Pure stands of ponderosa pine represent locations where ponderosa's tolerate the local environmental conditions better than all other tree species, and are therefore dominant. Where growing conditions for ponderosa are better, competition from other species, such as Douglas fir and aspen, limit ponderosa pine distribution.
Additionally, all trees studied at each site, regardless of age or species, begin growing in the spring at about the same time (within a week or two during most years). However, trees begin growing earlier in the year at lower elevations as it warms up sooner.
Lastly, we have been able to determine that trees tend to grow fastest during the early months of the growing season (i.e., April-July). Using this information in combination with fire scars found within the annual growth rings of trees across the Jemez Mountains landscape, strong evidence is revealed regarding the seasonality of historical forest fires. We can see that the vast majority (~95%) of historical forest fires occurred during the early growing season of ponderosa pine. This is important information for land owners of today's ponderosa pine forests within the Jemez Mountain landscape.
The fate of today's ponderosa pine trees remains unknown. However, as ecologists working at Bandelier National Monument continue the dendroband program, we will be better prepared to anticipate, and interpret, future landscape changes across the Jemez Mountain landscape.
Using historic photographs to track landscape changes in Bandelier National Monument
The Rio Grande
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Last month I was able to participate in one of our four yearly collections of ground dwelling arthropods at Bandelier. Sampled four times a year, these collections are designed for long-term monitoring of ground-dwelling arthropod diversity and population dynamics at Bandelier National Monument. Three sites were chosen to monitor different elevations and vegetation types within the park. Because arthropod populations can shift dramatically from year to year the long term nature of this study helps land managers tease out long term trends in these populations due to climate or land use changes that could signal broader changes to the ecosystem. Most studies of this nature are based on six year grants; this study is extremely rare in that it has been going on for over twenty years.
To collect samples from the pitfall traps my partner, Courtney, and I went out to each collection site armed with anti-freeze, ethanol, and a toolbox full of cups, cans, strainers, funnels, and chopsticks. Each 'pitfall' is a cup filled partially with bright green anti-freeze and stored securely in a soup can that is level to the ground. Anti-freeze is used in order to prevent evaporation and preserve the samples. We use a less-toxic version with a bittering agent to prevent animals from drinking it.
The traps are camouflaged using a rock or piece of wood to prevent insects from being tipped off by light reflecting off the anti-freeze. This can make the traps hard to find but a GPS and bright-colored flagging generally help us find the traps. Plus when carefully inspecting an area, 'floating' rocks, which are a sure sign of a pitfall trap, tend to stand out.
At each trap we strain out all the bugs in the cup. After collecting all our samples, a funnel and chopsticks help us fit our samples into glass vials to be sent to the University of New Mexico for identification. It is easier to place the larger insects in head first, not only because they fit better, but because many insects will stare at you with large eyes if you try to place them in the other way.
The beauty of the data collected comes from the large variety of species that have been tracked over the years. Data collected has revealed how individual species respond to environmental changes- including weather and fire. All new species collected are added to Bandelier's growing arthropod collection, housed at UNM's Natural History Museum (link: http://www.msb.unm.edu/arthropods/index.html), giving the project value in helping to build a catalog of what species can be found within the park. In fact, some previously undescribed species such as a new minute brown scavenger beetle in the family Lathridiidae and a new darkling beetle in the genus Steriphanus have been discovered from the pitfall traps at Bandelier. In addition our pitfall traps are designed using the same protocol as several pitfall sites located across the state of New Mexico allowing for invaluable comparison of diversity and species response over a broad-scale.
At Bandelier changes due to the El Niño Southern Oscillation (Link to NOAA ENSO page: http://www.elnino.noaa.gov/) weather pattern have been a particular focus of this project. El Niño has a strong impact on southwestern U.S. weather and its impact on arthropod diversity is continuing to be an interesting aspect of this long term study. This study has been able to gather data on diversity during normal years and assess changes in diversity due to La Niña (dry) years and El Niño (wet) years. In addition the elevation differences among the sites make it possible to study what effects higher elevation may have on diversity, due to its cooler temperatures, higher levels of precipitation, and differing vegetation types. In connecting these two factors it has been possible to see at which elevations populations are most susceptible to changes from droughts and shifting climate patterns.
Hiking down the switchbacks with our last set of arthropod samples in hand, I thought of how diverse the insect world is. Over the course of 102 traps we had seen an amazing variety of insects from tiny black ants to brown beetles that were too big for the funnel and almost too big for a vial. We collected an assortment of crickets, spiders, beetles and even velvet ants, which despite their name, are actually flightless wasps. It's fascinating to see what turns up in each trap, especially because many of the insects in our traps are so elusive in lifestyle and habitat as to rarely be seen by hikers. It was a great experience to be part of such a unique long term study on arthropod diversity.
Did You Know?
The Valles Caldera is the collapsed summit of the Jemez Volcano which erupted over 1 million years ago. Ash from this volcano formed the volcanic tuff from which the Ancestral Pueblo people built their homes.