Indicators and Thresholds Database


User’s Guide


Developed by the National Park Service’s

Washington Office, Denver Service Center & Alaska Regional Office

May 2006 , Revised November 2015





Purpose of the Database


The purpose of the database is to compile and share existing information on indicators and thresholds that have been used or suggested for monitoring resource conditions and visitor experiences in various land management plans and literature sources.  When trying to develop indicators and thresholds for an area, it may be helpful to consider indicators and thresholds already suggested or selected for other areas with similar resources, use patterns and/or visitor use issues (although it may not be appropriate to adopt the exact standard selected for another public land management area since thresholds should be based on the desired conditions of each area).  This database was developed as a tool to assist with the selection of indicators and thresholds.  There are many other resources available to teams attempting to develop indicators and thresholds, so this database should not be considered a sole source of information.


The database was developed by a team of NPS employees that wanted to compile information on indicators and thresholds developed by public land management agencies and the research community.  The team began by collecting many approved and draft plans that include indicators and thresholds developed by the National Park Service, United States Forest Service, United States Fish and Wildlife Service, and the Bureau of Land Management.  The team also collected literature sources and included some of the indicators suggested as part of research studies.  The database is not exhaustive of all possible sources, and it is not complete.  The hope of the development team was to create a tool that could be continually updated with indicators and thresholds as they are collected from existing sources or newly developed. 


The team made updates to the website in 2015 to reflect the latest guidance by the Interagency Visitor Use Management Council. You may find older terms in the text of database, such as VERP rather than visitor use management. We did not replace all original text in the database, which includes the website URL "usercapacity."


For background on indicators and thresholds, visitor capacity (previously referred to as user capacity or carrying capacity), and visitor use management please see the Interagency Visitor Use Management Council website.




The Indicators and Thresholds database is accessed by going to and clicking on the Indicators and thresholds link. The first page you see is the Database Search page. Because no search has been conducted, no indicators or thresholds are showing.


The main thing you see on the page is the search box. This is where you tell the program what information you are looking for: Agency, General Issue Category, Secondary Issue Category, Setting/Resource Type, and Facility/Site (see Database Structure in this guide for more information on these fields). Enter your search parameters by clicking on the drop-down arrow for each field and selecting your preference. If you have no preference, leave it on “all.” When the parameters are set, click the Begin Search button.


The program searches the entire database and returns a table containing only the records that meet your search parameters (note: a scroll bar will appear along the right side and/or across the bottom of the screen if the table is too large for your monitor to display all at once). Notice that the columns you searched on do not display as part of the table but remain visible in the search box. The search results page may be printed by clicking File, Print on your Internet browser menu bar. If you would like to view the entire entry, click on the magnifying glass icon that is at the left of each entry. The detail page may be printed also. Close this detail page to return to search results.


Occasionally, some entries will contain text that is too long to display in its entirety. When this happens, the word “more” will appear at the end of the allowed text. Click on this to see the entire entry.


Sorting. The entries displayed in the search results table may be sorted by a particular column alphabetically (or numerically in the case of the ID column). This is done by clicking on the column heading. The first click will sort in ascending order (A, B, C . . .) and clicking again will sort in descending order (Z, Y, X . . .). For example, if you wanted to sort the entries by Agency, just click on the column heading Agency.


Exporting: You can export the search results table as an Excel file (Excel is Microsoft’s spreadsheet application). Click on “export grid to Excel” found on the left side of the screen underneath the search box. This will export the entire table into an Excel spreadsheet that you can view on-screen or save to your computer, depending on your settings.





Each indicator and standard entry in the database has several fields of data.  Some of the fields are intended to identify the source of the information and provide contact information for further inquiry on the application of the indicator and standard.  Other fields are intended to allow the user to search various topics of interest and identify related indicators and possibly thresholds (if provided).  For instance, the database can searched to identify indicators and thresholds related to issue topics such as loss of vegetation, vandalism of archaeological sites, or visitor use volume/density.  Further, the database can be searched for indicators and thresholds applicable to certain settings types such as wilderness/backcountry areas, rivers, and developed areas.  Finally, the database can be searched for indicators and thresholds related to types of facilities such as campsites, trails, roads, boat docks and transit facilities. 


For each indicator and standard entry, the following information is provided in the database, as available:


Agency:    BLM, USFS, NPS, USFWS, other, interagency

Unit:    Name of the public land management area

Type of document:    Approved plan, draft plan, literature/study

Name and date of document:    Name of the document and its completion date if applicable

Contact name and phone:    If available, name of individual knowledgeable of the document

General issue category:    See below

Secondary issue category:    See below

Setting/resource type:    See below

Facility/site:    See below

Any additional clarification of the indicator that might be helpful:    Suggestions for clarification of terms or units of measurement

General comments:    Notes on the application of the indicator or if other thresholds were applied to different zones, or more information on the source or implementation of the indicator, etc.


The general issue category is the major category or topic that is the subject of impact represented by the indicator.  The secondary issue category is the more specific subtopic of impact represented by the indicator.  Each indicator was coded with both a general issue category and secondary issue category.  For instance, if the indicator was “# of damaged trees within 10 feet of a campsite,” the general issue category would be “vegetation” and the secondary issue category would be “injury.”  The list of general issue categories and secondary issue categories are below.




·        Vegetation

o       Injury (e.g., cut or broken limbs, defacing of tree trunk)

o       Removal/loss  (e.g., bare ground)

o       Change in community character

o       Existence of or potential introduction of exotic species

·        Soil

o       Loss

o       Compaction

o       Composition

o       Loss of soil crust

·        Water

o       Turbidity

o       Pollution (e.g., fecal coliform, inorganic chemicals, etc.)

o       Change in pH

o       Change in temperature

·        Air

o       Localized pollution

·        Wildlife/Fisheries

o       Population loss/change

o       Disturbance (e.g., change in activity, change in physiological characteristics such as heart rate)

o       Habituation 

o       Fragmentation of habitat

o       Loss of habitat

o       Change in community character

o       Existence of or potential introduction of exotic species

·        Geologic Features

o       Vandalism/theft/non compliance

o       Physical deterioration from allowed human use

·        Soundscape

o       Non-natural sounds

·        Archaeological

o       Vandalism/theft

o       Erosion

·        Historic Structures

o       Vandalism/theft/non compliance

o       Physical deterioration from allowed human use

·        Ethnographic

o       Vandalism/theft

o       Areas of disturbance (e.g., vegetation loss, erosion)

·        Crowding

o       Delays (e.g., wait times)

o       Use volume/density (e.g., people at one time/people per viewscape, LOS/traffic volume)

o       Encounters (e.g., encounter rates, ability to camp out of sight and sound of others)

·        Use conflicts

o       Discourteous/disturbing/distracting behavior (outside the spectrum of allowed use)

o       Conflicts between dissimilar, but allowed, activities (e.g., horse/bike, car/pedestrian)

o       Accidents

·        Aesthetics

o       Litter

o       Presence of waste (e.g., human, horse, dog)

o       Offensive odors

o       Other human impacts (e.g., campfire scars, carving on trees)

·        Park Infrastructure

o       Vandalism/theft/non compliance

o       Physical deterioration from allowed human use


The setting/resource type category and facility/site category identify the location where the indicator was applied.  Each indicator was coded with both a generic setting type and general facility type.  For some indicators a setting may not have been identified, or were applied to multiple settings, and therefore the code of “multiple zones” was applied.  Further, some indicators were not applied to a specific, designated facility, so the code of “general” was used in coding the facility/site category. The setting/resource type and facility/site categories are defined below.




·        Developed

·        Semi-developed

·        Backcountry/wilderness

·        Cultural site

·        River

·        Lake/Reservoir

·        Cave

·        Other sensitive resource area (e.g., research natural area)

·        Multiple zones




·        General (not directly tied to a facility type – e.g., floating a river, walking cross-country)

·        Non-motorized trails (e.g., hiker, equestrian, bicycle, x/c skiing)

·        Motorized trails (e.g., snowmobiling, ATV/ORV)

·        Campsites

·        Attraction sites (e.g., overlooks, geologic/natural features, monuments, historic structures)

·        Roads and parking

·        Transit hubs and facilities (e.g., shuttle buses, shuttle stops, intercept facilities)

·        Visitor contact facilities (e.g., visitor center, restrooms, outdoor plazas)

·        Picnic/day-use areas

·        Boat docks/marinas

·        Stock facility

·        Interpretive facility






Please send an e-mail to the following address with questions or comments on the indicators and thresholds database: This mailbox can also be accessed by clicking on contacts at the top of the database search page. Clicking on help will bring up this user guide.