Macro-invertebrate collection using Hester-dendy



Measuring depth at the location of a Hester-dendy

    On August 1, Jesse Bolli and myself set out a total of 14 Hester-dendy samplers in Cub Creek. They were placed at two different sites, with 7 being placed at each site. A Hester-dendy is a sampler made of 7 tempered masonite plates on a long bolt with some sort of spacer between the plates and a wing nut at the end of the bolt (see photos below). These are used to collect macro-invertebrates in steams with a silty substrate. If Cub Creek had a rocky substrate then it would be possible to collect the macro-invertebrates from simply turning over the rocks, but the lack of rocks then requires the use of the Hester-dendy sampler to provide a living space. The Hester-dendy sampler is placed it the stream for a month to allow the macro-invertebrates time to take up residence on them before they are collected. Water Quality data including depth at each placement site, along with pH, conductivity, turbidity, dissolved oxygen and temperature were taken when the Hester-dendy samplers were deployed on Aug. 1 and when they were collected on Aug 30. Water samples were also collected and used to test the level of e.coli. The e.coli test is performed by placing 1ml of the water sample on petrifilm and placing in a moist incubator for 24 hours.

      On August 31, I set out with Ranger Jesse Bolli and SCA Molly Watters to collect the Hester-dendy samplers. We placed each Hester-dendy in a container, along with some of the creek water and transported them back to the maintenance area at the monument. Once we collected all 14 and took water quality data at all of the sites (except one, since the water level of Cub Creek dropped and left the Hester-dendy out of the water) we could take them apart and collect the macro-invertebrates into containers.  The method used to collect the macro-invertebrates required one person to work on only one site's Hester-dendy at a time. We would place a sieve in a bucket and pour the water from the container and the hester-dendy into it. We then unscrewed the wing nut holding the plates together and using water pressure and soft brushes rinsed all macro-invertebrates into the sieve. After removing as much detritus as possible we were ultimately left with all of the macro-invertebrates that were living at that site in the sieve. They were then placed in a bottle, filled with alcohol and labeled with the site ID and date. These bottles will be shipped to the Heartland Monitoring Network for identification and this info along with the water quality data collected at the sites can then be used to help determine how healthy Cub Creek is.
For more information about the Heartland Monitoring Network please visit: http://science.nature.nps.gov/im/units/htln/


Ranger Jessi Bolli and SCA Molly Watters



A collected and uncleaned Hester-dendy

Taking apart the Hester-dendy's

NASA Astronaut Clayton Anderson visits Homestead National Monument



Me with Clayton Anderson

Founders Day, or August 25, 2012 was the 96th anniversary of the establishment of the National Park Service. Homestead National Monument invited Nebraska native and NASA astronaut Clayton Anderson to do a program at the monument on Founders Day, discussing the new frontier- Space. Clayton Anderson's program was very interesting and enlightening. He was a very down to earth guy with great story telling skills. He wandered around the crowd talking to people and posing for pictures before the program even began. He then started his program with some pictures and he got the audience involved by asking them to think what the captions might be. After taking a few suggestions from the crowd, he would reveal his captions. His captions always got a laugh out of the crowd. In many of the pictures of him in space, there was always something Nebraska related, most often a Nebraska Huskers hat, or the big red 'N' which he always had with him an all of his space walks. He talked a little about what life the the space station was like and then he went on to draw comparisons between the old frontier and the new frontier, similarities like problems with being able to travel long periods of times with only limited supplies. The whole program was very interesting and the crowd  seem to really enjoy it. At the end of the program he took some questions from the audience. Afterwards he stayed around to sign more autographs and pose for more pictures.

Panorama view of Clayton and the audience

Clayton Anderson with artist Michael Carroll's from Long-ships
to Space-ships painting, on loan form the Planetary Society

Clayton Anderson is a truly genuine guy that enjoys sharing his stories of space. He is also very proud of the fact that he is the only astronaut from Nebraska, and that he will always be the first astronaut from Nebraska. It was great to have him speak at the monument, he drew a crowd that ranged from infants to the elderly, and all seemed to enjoy the program equally. The evening ended with a watermelon feed sponsored by the Friends of Homestead and a video from the Lincoln Prairie Astronomy club. Unfortunately the star gazing had to be cancelled due to inclement weather, but it has been rescheduled for October 20th, during the Howling Homestead program.

This program is just another great example of the excellent programs that Homestead National Monument offers the surrounding communities. If you are in the area you should check out the website at www.nps.gov/home to see a list of upcoming activities and programs, including the Living Homesteader Reunion and Living History Extravaganza on Labor day weekend, Bill Nye the 'Planetary' guy on Sept 23, the Hedge Apple Festival on Oct 7 and Howling Homestead on Oct 20, along with many others.

Thicket Mapping at Homestead National Monument

2012 Homestead National Monument Thicket Map

Homestead National Monument of America was established to tell the story of  the Homestead Act. While the monument tells the story of homesteaders, they also strive to show to visitors what the tall grass prairie would have looked like to those original homesteaders. Therefor the monument has over the last decade began to monitor and remove woody species that would not have been in the tall grass prairie of the past. Smooth Sumac (Rhus) covers almost 24 acres of the 120 acres of tall grass prairie. Dogwood (Cornus) is the other big issue species. Plum (Prunus), Ash (Fraxinus) and Elderberry (Sambucus) are also present as thickets. There are also a small umber of trees such as Eastern Cedar, some other deciduous trees and quite a few Honeylocust. The numbers that are in the key, 1-4 refer to the density of each thicket. Thickets rated a with a number 1 are the thickest and 4 are the thinnest. At present 34 acres of the prairie are currently covered by thicket. Mapping has been done about 5 times in the last 10 years. This year I was the one that did all of the mapping. I used a Trimble GPS with an external antenna attached to a back pack I wore. I had to identify  thicket species and density and then walk around the perimeter of each thicket. The data was then downloaded and Natural Resource Specialist Jess Bolli made the map that is at the beginning of this blog. Once the location and density of the thickets is recorded, treatment and removal can begin. Numerous different treatment methods have been tried including foliage treatment with different chemicals and also the cut and spray  treatment method. Much thought is put into choosing chemicals and treatment methods. The monument wants to control the amount of tickets present on the prairie while causing no harm to wildlife or desirable native plants. For this season, both foliage and cut and spray methods are being employed. So, for any of you that have visited the prairie, all of the red areas are dogwood and sumac thickets that have been treated by chemicals applied to the foliage. Starting this week I will be out in the prairie beginning with cut and spray treatment of some of the thinner thickets. Hopefully the treatment this year will stop the spread of the thickets and perhaps it will even begin to shrink the size of the thickets. Homestead National Monument is committed to showing all its visitors what the tall grass prairie would have looked like to the homesteaders just arriving in the area.

More on Soundscape

Basically the efforts of the listening center results in a few different graphics once I run the data through the 'R' program. I find that the bar graph is the most understandable. The listening center, I analyze 8 days for every site, and each day is split into 10 seconds for every 2 minutes. This comes down to 2 hours worth of data that I listen to. Every sound I hear has a code that I enter, like 2.4 is a truck, 9.1 is a domestic dog or 23 for thunder. When I run the results through the AMT program I can chose any code that I want highlighted on the graph. Right now I have run the program to highlight all vehicle sounds as compared to all audible noises. The nice thing about the resulting graph is that is is easy to compare different seasons at one site or to compare the same seasons at the same site. The graphs that I have included are for the same site but at different seasons. You can see that traffic is audible for a higher percentage of time than in the summer, I am going to assume that the lack of foliage in winter is what has resulted in this difference. 

As you can guess being able to run this graph for almost any possible noise, man made and natural, can be both interesting and informative. The information in these graphs and in the other soundscape data can allow parks to establish base line acoustical data and allow them to make informed management decisions. Some parks like Zion have soundscape management plans, the Grand Canyon used the information to help develop air tour management plans and Yellowstone used soundscape information in their winter use plan. I encourage you to visit the NPS Natural Sounds and Night Skies website if you are interested in more information about soundscape.

The Science of Sound- Soundscape Monitoring at Homestead National Monument

Many people are familiar with the concept of a landscape, and yet they have given no thought to the soundscape. The soundscape of an area is important as the landscape, who wants to go into the wild and see an amazing view, only to hear constant traffic and man-made noises. The National Park Service created the Natural Sounds and Night Skies division to help parks manage their soundscapes.  I was lucky enough to attend a training with some of the NPS Natural Sounds staff in Denver back in May of this year. The training explained the mission of the Natural Sounds program, trained us in the set-up and take-down of acoustical monitoring equipment, and the analysis of all the data collected.

The National Park Service Management Policy from 2006 states in section 4.9 : Park natural soundscape resources encompass all the natural sounds that occur in parks, including the physical capacity for transmitting those natural sounds and the interrelationships among park natural sounds of different frequencies and volumes. Natural sounds occur within and beyond the range of sounds that humans can perceive, and they can be transmitted through air, water, or solid materials. The National Park Service will preserve, to the greatest extent possible, the natural soundscapes of parks. The Service will restore to the natural condition wherever possible those park soundscapes that have become degraded by unnatural sounds (noise), and will protect natural soundscapes from unacceptable impacts. (http://www.nps.gov/policy/mp/policies.html#_Toc157232745) All of the data collected allows parks to establish base line data and help them to create management plans to protect soundscape and help to restore soundscapes in areas where they have been degraded. 

Soundscapes are important for many reasons, among them allowing animals to hunt and visitors to appreciate the sights and sounds of the parks. If you are interested in more information about the importance of sound please visit the NPS Natural Sounds and Night Skies website at: http://www.nature.nps.gov/sound/

Homestead National Monument of America realized the importance of sounds on the monument and reached out to the NPS Natural Sounds and Night Skies program. The monument purchased the necessary equipment to begin gathering acoustical data. The equipment included a SPL (Sound Pressure Level) meter, microphone, mp3 recorder, anemometer (wind), battery and tripods. In August of 2011, a technician from the Natural sounds program came to the monument to teach Natural Resource Management Specialist Jesse Bolli how to set up/take down the equipment and transfer the data to the computer. 

Jesse began to collect data from various sites during the fall and winter. The equipment normally gathers data for approximately 20 days at each site. Jesse set up the equipment 5 times before I arrived on site and we have set it up together once since I received my training. This left me with 6 sets of data to analyze. The NPS Natural Sounds program has developed a program call the Acoustical Monitoring Toolbox. I use many of the features of this program to turn the raw data into something more understandable. The next four graphics are spectrograms for one day at two different sites. I created these images using the AMT (Acoustical Monitoring Toolbox). The first image is of a site close to the road. The more yellow in an image indicates that it is loud, blue colors indicate quieter sounds. All of the white/yellow spikes indicate when a vehicle passed. The second graphic is for the same day at the some site, but is corrected to show only the frequencies that the human ear can pick up. The last two graphics are for a site that is in the woods and much further from the road (site 4). The fact that there is much more blue than yellow shows that the second site is much quieter than the first site. It is also a good example of how it is louder during the day time hours than in the nighttime hours.

Spectrogram- Site 1

Spectrogram (A-weighted) adjusted for human hearing, Site 1

Spectrogram, Site 4

Spectrogram (A-weighted) adjusted for human hearing, Site 4

This graphic was created using the AMT and a program called 'R' running a script created by the Natural Sounds program. It compares how loud a noise is and at what frequency it is at. These graphs are interesting to look at as they split up day and night and show ranges where transportation, conversation, and song birds fall.

The biggest part of data analysis is listening to the sounds that were recorded. For each site 8 days are analyzed. The AMT has a program that splits the audio into 10 seconds clips for every 2 minutes, meaning that you listened to 2 hours of audio per day analyzed. The audio is then listened to in a program call the Listening Center, which allows the listener to assign a number to each individual sound. Once numbers are assigned, the data can be ran through the 'R' program to create graphic that can show what percentage of time trucks or birds or any specific sound was heard.

Screen shot of Listening Center.

 The anemometer gathers wind speed data, which is important in choosing what days are analyzed. Days with little wind are much easier to listen to. It also allows us to see what days or times may not be analyzed by AMT software, since days with wind speeds above 5 m/s (meter per second) are not analyzed.

Wind Data

The following two tables were created by the Natural Sounds program as a base to compare site specific numbers to.

Sound pressure level examples
Park Sound Sources	Common Sound Sources	dBA
Volcano crater (HALE)	Human breathing at 3m	10
Leaves rustling (CANY)	Whispering	20
Crickets at 5m (ZION)	Residential area at night	40
Conversation at 5m (WHMI)	Busy restaurant	60
Snowcoach at 30m (YELL)	Curbside of busy street	80
Thunder (ARCH)	Jackhammer at 2m	100
Military jet at 100m AGL(YUCH)	Train horn at 1m	120

Effects of sound pressure levels on humans
SPL (dBA)	Relevance
35	Blood pressure and heart rate increase in sleeping humans (Haralabidis et al., 2008)
45	World Health Organization’s recommendation for maximum noise levels inside bedrooms (Berglund, Lindvall, and Schwela, 1999)
52	Speech interference for interpretive programs (U.S. Environmental Protection Agency, 1974)
60	Speech interruption for normal conversation (U.S. Environmental Protection Agency, 1974)

I created the following two tables using the data collected by the SPL (Sound Pressure Level) meter. The 20-1,250 range is the lower frequencies, which consists of mainly traffic, while the 12.5-20,000 includes all of the frequencies that were collected. The first table shows the percent time that noise was above a certain level, it is broken up by day an nigh hours and shows data for two different seasons at the same site.

Percent time above for summer and winter
Site	Frequency (Hz)	% Time above sound level: 0700 to 1900				% Time above sound level: 1900to 0700
		35dBA	45dBA	52dBA	60dBA	35dBa	45dBA	52dBA	60dBA
HOME001 Winter	20-1,250	88.2	15.84	1.73	0.04	83.40	9.33	0.49	0.01
	12.5-20,000	92.02	18.77	2.21	0.05	85.15	11.09	0.58	0.01
HOME001 Summer	20-1,250	93.87	10.71	1.56	0.03	69.13	2.78	0.15	0.00
	12.5-20,000	100	99.93	73.81	0.32	100	100	91.76	28.49

Exceedence levels (Lx) represent the sound pressure levels exceeded x percent during the  given measurement period (e.g. L90 is the SPL that has been exceeded 90% of the time). For the following table, the top value reports the Lx for the 20 – 1,250 Hz subset of the frequency range, and the bottom Lx value is calculated from the 12.5 – 20,000 Hz spectrum.  Exceedence levels for existing conditions
Site	Frequency (Hz)	Exceedence levels (dBA): 0700 to 1900			Exceedence levels (dBA): 1900 to 0700
		L90	L50	L10	L90	L50	L10
HOME001 Winter	20-1,250	35.2	40.1	45.5	35.7	38.8	43.3
	12.5-20,000	35.8	40.7	46.4	35.9	39.2	43.7
HOME001 Summer	20-1,250	36.0	39.1	44.6	34.8	36.6	40.3
	12.5-20,000	51.9	53.6	55.2	57.9	59.0	60.0