National Park Service

State of the Park Reports

State of the Park Report for Organ Pipe Cactus National Monument

Natural Resources

Columnar Cactus Habitat at Organ Pipe Cactus NM
Columnar Cactus Habitat at Organ Pipe Cactus NM

View list of natural resource information sources

Click to expand and contract panels. Expand All / Collapse All

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Air Quality Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Deposition Sulfate Resource is in good condition; condition is improving; medium confidence in the assessment. Since 1980, when copper mining and smelting were still active in Ajo, sulfate concentrations in wet deposition have decreased. More recent data (1999–2009) indicate no near-term change. According to the NPS Air Resources Division, sulfur conditions are good at OPCNM (National Park Service 2010; NPS ARD 2013).
Nitrate and Ammonium Condition of resource warrants significant concern; condition is unchanging; medium confidence in the assessment. No trends have been seen in nitrate concentrations in precipitation from 1999–2009. However, the NPS Air Resources Division rates nitrogen conditions as being of significant concern due to off-park activities (National Park Service 2010; NPS ARD 2013).
Visibility Haze Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. In 2008, ammonium sulfate (40.6%) and coarse mass (26%) were the major sources of haze-causing fine particulates at OPCNM. Ammonium sulfate comes mainly from coal-fired power plants and smelters; coarse mass consists of wind-blown dust. Other particles consisted of organic carbon (15%), fine soil (10%), sea salt (4.4%) and elemental carbon (4%). Organic carbon comes primarily from combustion of fossil fuels and vegetation. Since aerosol monitoring began at OPCNM in 2003, the highest concentrations of nitrate particles in the air occurred in winter 2008–2009. Peak concentrations of fine soil occurred in fall 2006 and spring 2007, coinciding with high PM2.5 (particulate matter < 2.5 micrometers) levels (National Park Service 2010; NPS ARD 2013). Brief - Visibility

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Water Quantity and Quality Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; medium confidence in the assessment.
Tinajas ("large earthen jars" in Spanish) occur naturally and are generally ephemeral being primarily fed by surface runoff following rainfall events. Tinajas represent most of the key surface water features of Organ Pipe Cactus National Monument. In addition, three spring complexes—Quitobaquito, Bull Pasture, and Dripping Springs—are perennial, groundwater-driven systems. Collectively, these scattered water bodies represent important and isolated aquatic habitats within the park, providing important ecosystem services for the larger terrestrial landscape. Water quality, quantity, and ecological characteristics of these sites have been sampled periodically, although their remote, rugged locations combined with recent border-related activity have restricted monitoring efforts. In 2010 and 2011, the Sonoran Desert Network collected baseline data as part of the enhanced Climate Change Monitoring Program for parks of the American Southwest. By contrast, groundwater data has been collected by park staff and cooperators since 1977, providing an excellent record on trends in this important resource.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Surface Water Quality E. coli Resource is in good condition; trend in condition is unknown or not applicable; medium confidence in the assessment. A recent inventory of known springs and tinajas provides baseline water quality for tinajas and springs at OPCNM. E. coli concentrations at 33 springs and tinajas were 1.55±0.56 MPN (most probable number)/100ml of water. The highest observed value was 13.5MPN/100ml—well-below the state standard of 235MPN/100ml for partial body contact.
  • Specific Conductance
  • Dissolved Oxygen
  • pH
  • Temperature
Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; medium confidence in the assessment. The 2010–2011 inventory documented core water quality parameters for 41 springs and tinajas. Dissolved oxygen observations ranged from hypoxic, or levels of dissolved oxygen less than what typical organisms need to thrive (e.g., 0.53 mg/L at Dripping Spring), to hyper-saturated in more productive systems (e.g., several of tinajas in the Ajo Mountains). pH was similarly variable and generally basic, with a mean value of 9.06, probably due to geologic factors. Specific conductance and water temperature were all within normal ranges for desert aquatic systems.
Surface Water Quantity Discharge/water level Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; medium confidence in the assessment. Water quantity is by far the most important ecohydrologic feature of tinajas and springs. The 2010–2011 inventory documented local evidence (water stains on rocks, vegetation) suggesting that water quantity was within recent natural variability. Historic data is generally lacking, although relatively low water levels were documented in 2001–2003, possibly due to drought.
Human Use 4-level rapid assessment tool Condition of resource warrants significant concern; trend in condition is unknown or not applicable; medium confidence in the assessment. The 2010–2011 tinaja inventory collected impact data at 47 sites: 43% (20 sites) had some level of migrant or smuggler impact. Of these sites 55% was slight impact, 35% moderate impact and 10% heavy impact. The Spring Monitoring protocol currently under development will incorporate metrics to quantitatively assess such impacts. Human use of tinajas and springs likely affects utilization of these resources by wildlife.
Groundwater Depth to groundwater near U.S. / Mexico border Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. Depth to groundwater for wells near the U.S./Mexico border has increased steadily from 1987–present, with increases generally exceeding 20 feet. Withdrawals for agricultural and municipal development in the Sonoyta (Mexico) area are a likely cause of water table decline. The four wells nearest the Lukeville, AZ port of entry have shown the greatest decline when compared to their long-term averages declining at a rate of approximately one foot per year.
Depth to groundwater away from U.S. / Mexico border Condition of resource warrants moderate concern; condition is unchanging; high confidence in the assessment. Depth to groundwater has generally been shallower for wells remote from the Lukeville/Sonoyta areas and any recorded declines have not been as consistent or dramatic. These wells have, however, exhibited temporal and spatial variation from 1987–present which could be due to natural causes.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Quitobaquito Condition of resource warrants significant concern; condition is unchanging; high confidence in the assessment.*see note belowBrief - Quitobaquito Pond
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Water Quantity and Quality
  • Spring discharge
  • Pond depth
  • Basic water quality parameters
Condition of resource warrants significant concern; condition is unchanging; high confidence in the assessment. Spring discharge is currently steady but has declined over the past 40 years. Pond depth had been restored after a 4-year crisis period, but remains a significant concern because of the temporary nature of some of the repairs. Large-scale water losses resumed in 2012 and can be expected again in summer 2013. A more long-term repair is required and should be completed soon. Water quality is stable.
Vegetation Overall health of plant community Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. Today, Quitobaquito is at risk of a catastrophic fire due to heavy fuel loads. Fuels have not been managed in the area for about 40 years. As a result, minor seeps are buried by accumulated dead material and many woody perennials such as mesquite are dead or dying. Bulrush, a native plant that grows around the pond perimeter, colonized new areas during the low-water period of 2005–2010. Continuous bulrush management is required to keep open and shallow water in the pond. Bermuda grass occurs throughout the wetland and competes with natives.
Quitobaquito Pupfish
  • Abundance
  • Habitat stability
Condition of resource warrants moderate concern; condition is improving; high confidence in the assessment. Number of pupfish has returned to previous levels (> 9,000) after a period of extended low water. Approximately 2,500 Quitobaquito pupfish are held in off-site refugia, at monument headquarters, the Arizona-Sonora Desert Museum, and Cabeza Prieta National Wildlife Refuge.
Sonoyta Mud Turtle Abundance Condition of resource warrants moderate concern; condition is unchanging; high confidence in the assessment. The number of Sonoyta mud turtles at Quitobaquito (excluding young of the year) has varied from 39 to 156 (average 97.2 based on 15 years of census data). Census efforts in 2007 and 2011 yielded estimates of 119 and 156 turtles, respectively.
Cultural Resources
  • Condition of Cultural Landscape
  • Prehistoric and Historic features
Condition of resource warrants moderate concern; condition is unchanging; high confidence in the assessment. A cultural landscape inventory has recently been completed for Quitobaquito. Like the natural landscape of this system the cultural landscape remains vulnerable to change as monitoring, protection, and management are complicated by border related activities.

* Despite yellow ratings for four of the five indicators of condition, we nonetheless have rated Quitobaquito's overall condition as red because the system's underlying instability remains. Known sources of water loss are currently only partially sealed with a temporary patch and this patch began to fail in 2012. Total loss of the pond is an imminent threat in the absence of a long-term repair of this known problem. Such an occurrence would turn several more of indicators red with deteriorating trends.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Soils and Geology Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Deposition and Erosion of Sediments
  • Airborne dust
  • Visual observations
Significant cause for concern, declining trend, and medium confidence Traffic counts (vehicles per day) have more than doubled on some un-paved park roads. High traffic volume has significantly increased airborne dust (see Air Quality section). Such increases in airborne dust are known to cause declines in biological soil crust and plant productivity, resulting from being coated in dust. (See Ecosystem Structure and Function section.)
Water erosion & deposition rates Significant cause for concern, declining trend, and medium confidence Throughout the monument, vehicle routes and trails created during the past decade have captured, blocked, or channelized sheet flow, triggering accelerated erosion and causing localized loss of soils. Backcountry park roads have degraded significantly due to sustained increases in high traffic volumes; many roads are now below grade and capturing runoff. Some road segments are now deep drainages with gullies forming on either side. During the 20th century, livestock grazing triggered accelerated erosion that resulted in the loss of millions of tons of soil from the monument. Accelerated soil erosion continues at some of these sites but has slowed in others. The Armenta Ranch area gully system has been recently studied by the Arizona Geological Survey; a report is in progress that will discuss erosion triggers and rates of soil loss.
Soil aggregate stability class (1–6) Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; low confidence in the assessment. Surface soil aggregate stability provides an indicator of site disturbance and site resistance to soil erosion. Preliminary monitoring data indicate soils aggregate stability under vegetation (360 sample points) and soils without vegetation cover (543) were 4.1±0.1 and 3.4±0.8, respectively, with high between-site variance. A score of 6 is the most stable, whereas 1 represents the most unstable.
Valley Bottom Soils
  • Compaction
  • Aggregate stability
  • Off-road vehicle use and trail densities
Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. More off-road vehicle use has occurred on these soil types than any other soil group in the park. These soils tend to be fine-grained and young (less than 10,000 years old), and degraded sites can often be recovered if accelerated erosion has not occurred. Preliminary data from a two-year study indicate that off-road vehicles and foot travel cause soil compaction, which can slow rainfall absorption and capture, block, or channelize sheet flow or change drainage patterns.
Bajada Soils
  • Compaction
  • Aggregate stability
  • Off-road vehicle use and trail densities
Caution, declining trend, and low confidence Due to the more rugged terrain, bajadas have experienced less off-road vehicle use than flatter valley bottom areas. The terrain does not appear to discourage high-volume foot traffic. Soils of bajadas contain a lot of rocks so they may be more resistant to physical damage. Data from a three-year study to examine these impacts is currently being analyzed.
Desert Pavements
  • Compaction
  • Aggregate stability
  • Wind erosion
Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. Desert pavements are hundreds of thousands of years old and older. They are characterized by a surface layer of tightly packed dark stones and a subsoil laden with salts and clay. The surface pavement protects the soil from wind erosion. Once disturbed, the pavement can take decades to centuries to re-assemble, while the distinctive dark coloration may require several thousand years. Off-road vehicle activity sometimes exposes or disturbs the fine particles in the subsoil, which become prone to wind and water erosion that is very difficult to halt. Recovery from these types of disturbance is difficult and exposure to such disturbances should be avoided. Data from a two-year study to examine these impacts is currently being analyzed.
An unauthorized vehicle route on valley bottom soils in the San Cristobal Valley, OPCNM, 2011
An unauthorized vehicle route on valley bottom soils in the San Cristobal Valley, OPCNM, 2011.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Threatened, Endangered, and Rare Species Condition of resource warrants moderate concern; condition is unchanging; high confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Acuña Cactus
  • Survival
  • Reproduction
Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. During the past 22 years, the number of plants greater than 25 mm (1 inch) tall in six plots declined from 194 plants in 1992 to 37 plants in 2010. With few larger plants left to reproduce, the total number of plants in these plots is likely to remain low for many years.
Cactus Ferruginous Pygmy-Owl Abundance Caution, declining trend, and low confidence Monument staff monitored the pygmy-owl from 1995 through 2005, at 8–10 territories annually. Since 2005, monitoring has been largely curtailed due to the combined influences of delisting, large increases in illegal border-related activities, and associated changing work priorities for NPS staff. However, visits to territories in the higher-quality habitat continue to indicate that they are still occupied annually.
Quitobaquito Pupfish
  • Abundance
  • Habitat stability
Condition of resource warrants moderate concern; condition is improving; high confidence in the assessment. Number of pupfish has returned to previous levels (> 9,000) after a period of extended low water. Habitat is restored and stable, but actions to secure long-term habitat stability are yet to be implemented. Approximately 2,500 Quitobaquito pupfish are held in off-site refugia, at monument headquarters, the Arizona-Sonora Desert Museum, and Cabeza Prieta National Wildlife Refuge.
Sonoran Desert Tortoise Abundance Condition of resource warrants moderate concern; condition is unchanging; low confidence in the assessment. For the 25 repeated transects, 1995 and 2005 survey periods had very similar numbers of tortoise detections.
Sonoyta Mud Turtle Abundance Condition of resource warrants moderate concern; condition is unchanging; high confidence in the assessment. The Sonoyta mud turtle at Quitobaquito matures in seven years, and numbers of individuals (excluding young of the year) vary from 39 to 156. The most recent population estimates were 119 in 2007, and 156 in 2011. Habitat is restored and stable, but actions to secure long-term habitat stability are yet to be implemented. Brief - Sonoyta Mud Turtle
Sonoran Pronghorn
  • Abundance
  • Distribution
Condition of resource warrants significant concern; condition is improving; high confidence in the assessment. In 2012, Sonoran pronghorn continued to recover from the crisis year of 2002. Animals from semi-captive population are being released to supplement the wild population. The current estimate for the wild population is 159 animals, distributed across ORCNM, Cabeza Prieta National Wildlife Refuge, and Barry M. Goldwater Range lands. Brief - Sonoran Pronghorn
Lesser Long-nosed Bat
  • Abundance
  • Roost security
Resource is in good condition; condition is improving; high confidence in the assessment. The main OPCNM colony has tripled over the last 15 years, but is vulnerable to disturbance, and border-related activity takes place in the area. The nearby large colony in Mexico has decreased by a comparable number; there may be no net change in regional population if they moved here.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Invasive Species Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Buffelgrass and Fountaingrass, Ajo & Diablo Mountains Number of sites in management zone Condition of resource warrants moderate concern; condition is improving; high confidence in the assessment. Of 243 sites in the management zone that were visited at least three years in a row, over two-thirds have remained free of buffelgrass for two years. Nearly all treated sites showed a decline in the number of plants.
Buffelgrass in the rest of OPCNM Abundance Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. The buffelgrass management program at OPCNM began in 1994 and was focused on the south boundary area of the park. Management actions were successful but had to be discontinued when illegal border activities caused increasing concern over staff safety. Buffelgrass has begun to increase in number at known sites in unmanaged areas. In addition, new locations of buffelgrass are discovered but not managed in locations outside of the current management area.
Other Non-Native Invasive Plants Number of species Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. Nine species of invasive or potentially invasive plants arrived in OPCNM during the past 10 years. Several species arrived more than once. Most newly-arrived species were found in construction areas along State Route 85.
Trespass Livestock
  • Number of intrusions
  • Number of fence breaks
Caution, declining trend, and low confidence There has been a considerable increase in the number of fence breaks associated with border activities in recent years. This in turn has caused an increase in the frequency of cattle, horses, and feral burros entering the park, resulting in resource damage, possible disease transmission, and public safety hazards (livestock on roads).
Feral Dogs Number of intrusions Condition of resource warrants moderate concern; condition is unchanging; low confidence in the assessment. Feral dogs have been a persistent problem along the international border, in proximity to Sonoyta, Mexico. The 5-mile pedestrian fence may be reducing this impact, but it does continue. Feral dogs have multiple adverse impacts on wildlife.
Africanized Honey Bees Number of colonies reported and treated Condition of resource warrants moderate concern; condition is unchanging; low confidence in the assessment. A limited number of colonies of Africanized honey bees are present in the monument, and are treated each year only if presenting a hazard due to their proximity to other project areas.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Plants Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Columnar Cacti Aerial extent Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. The persistent drought, warming temperatures, and shortening winters (Weiss & Overpeck 2005, IPCC 2007 Synthesis Report) are drivers that are likely to change the geographic range and local distribution of many species, including columnar cacti in OPCNM—organ pipe, saguaro, and senita. These freeze-intolerant species are limited by cold temperatures. As climate change progresses, we expect these species in areas previously too cold to inhabit.
Timing of flowering Resource is in good condition; condition is unchanging; medium confidence in the assessment. The timing and amplitude of flower and fruit production in columnar cacti is important for the cacti as well as many wildlife species, including the endangered lesser long-nosed bat. Three years of phenology monitoring revealed remarkable consistency in timing with variation of two weeks or less in the annual cycle. Peaks in average numbers of flowers and fruit varied up to three-fold between lowest and highest years in both species. All adult organ pipes produced fruit each year, compared to a 95% average for fruiting adult saguaros.
Native Plants Mortality of drought-adapted plants Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. During the past ten years, there has been a sharp increase in the death or die-back of drought-adapted, long-lived perennial plants such as creosote bush, ironwood, linear-leaf saltbush, triangle-leaf bursage, big galleta grass, mesquite, and others. Death of creosote bush, one of the most drought-tolerant plants in the world, signals an important increase in environmental stress. A persistent drought, higher than average temperatures and shortening winters (Weiss & Overpeck 2005) could be contributing factors. Major changes in ecosystem structure and function and shifts in species geographical ranges are predicted for this century (IPCC 2007 Synthesis Report).
High-elevation Plants
  • Aerial extent
  • Number of plants
Caution, declining trend, and low confidence Some plant species occur only in the upper elevations of Sonoran Desert Mountains. These areas provide the cooler, moister habitats these plants require. As climate change progresses, these rare habitats may be lost as temperatures warm, annual rainfall declines and winters shorten. Species such as Juniperus arizonicus, Quercus turbinella, Vauquelinia pauciflora ssp sonorensis, and Perityle ajoensis could be extirpated from OPCNM. These extirpations would be consistent with predictions that range contractions will occur in the next century (IPCC 2005).
Heritage Plants Number of individuals Condition of resource warrants significant concern; condition is deteriorating; high confidence in the assessment. Several cottonwood trees were planted at Quitobaquito springs during the late 1800s and early 1900s. Four of the original six iconic trees remain and are important to the visiting public and neighboring tribes. Mission figs and pomegranates are traditional Spanish mission plants and were grown by O'odham farmers at Quitobaquito Springs during the past century. As such, they are an important part of this culturally significant area. During the past five years, all mission figs and all but five pomegranates have died due to lack of care and drought conditions. The remaining plants are in poor condition. Management access to the area has been difficult due to border-related safety concerns.
Plant Species Inventory Completeness Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; high confidence in the assessment. An inventory of plant species in the Ajo Mountains is 95% or more complete, but checklists for the central and western mountains as well as large basins are incomplete. The summer annual flora is poorly documented. This knowledge will become important as climate change affects the vegetation of the Sonoran Desert.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Terrestrial Vertebrate Animals Resource is in good condition; condition is unchanging; medium confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Diurnal Lizards
  • Species richness
  • Abundance
Resource is in good condition; condition is unchanging; high confidence in the assessment. Species richness appears to vary with the El Niño climate cycle, as some species recolonize individual study sites in response to abundant winter rains and disappear during dry periods. Species richness rebounded sharply in 2004 from a drought whose severity peaked in 2002. The abundance of small-bodied species such as the side-blotched lizard has been increasing, whereas abundance of large-bodied species such as the western whiptail has been declining.
Snakes
  • Species richness
  • Abundance
Resource is in good condition; condition is unchanging; low confidence in the assessment. Species richness and abundance vary over time with no significant trends at the single monitoring area. Fluctuations generally track lizard and rodent abundance.
Birds Species richness Resource is in good condition; condition is unchanging; high confidence in the assessment. 10 years of bird monitoring data for OPCNM are currently being analyzed for a status and trend report. Preliminary results indicate that bird species richness may have slightly increased over that period, suggesting that new species (perhaps favored by the warmer recent temperatures) are colonizing park habitats.
Bats
  • Species richness
  • Abundance
Resource is in good condition; condition is unchanging; low confidence in the assessment. Species richness has not fluctuated significantly since the mid-1990s. Captures of some species, such as Townsend's big-eared bat, have increased, while others, such as cave myotis, have decreased. Bat monitoring has been reduced to three mist-netting sites in recent years due to border security issues.
Nocturnal Rodents
  • Species richness
  • Abundance
Resource is in good condition; condition is unchanging; high confidence in the assessment. The number of nocturnal rodent species in the park has remained the same since regular monitoring began in 1991. No species have been lost, nor have new species appeared. Relative abundance of kangaroo rats has been below average for the past five years, whereas the smaller-bodied pocket mice are at their highest population level since 1992. Murids, including pack rats, are near average and last peaked in 2010.
Large Mammals Visual count Caution, declining trend, and low confidence Aerial surveys conducted in 1994 and 2006 revealed declines in white-tailed deer, mule deer, desert bighorn sheep, and javelina. A similar survey is being planned for late 2012. Remote detection cameras have been used to document the continued presence of ungulates, carnivores, and other large animals.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Soundscapes Caution, declining trend, and low confidence
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Sound Levels Percent time above threshold level Caution, declining trend, and low confidence The monument recently began monitoring soundscapes at selected sites where human activity or technology may affect Sonoran pronghorn and other sensitive wildlife, such as movement corridors and foraging areas. Preliminary results indicate noise levels exceeding 35bBA from 18 to 100% of the time at 3 sites in 2009. (Warner 2012). Soundscape monitoring data also show an increase in motor vehicle traffic in the Growler Valley between 2009 and 2011.

⇑ To Top of Page

The Status and Trend symbols used in the summary table below and throughout this report are summarized in the following key. The background color represents the current condition status, the direction of the arrow summarizes the trend in condition, and the thickness of the outside line represents the degree of confidence in the assessment. In some cases, the arrow is omitted because data are not sufficient for calculating a trend (e.g., data from a one-time inventory or insufficient sample size).

Condition Status Trend in Condition Confidence in
Assessment
Condition of resource warrants significant concern Warrants Significant Concern Condition is improving Condition is Improving High confidence in the assessment High
Condition of resource warrants moderate concern Warrants Moderate Concern Condition is unchanging Condition is Unchanging Medium confidence in the assessment Medium
Resource is in good condition Resource is in Good Condition Condition is deteriorating Condition is Deteriorating Low confidence in the assessment Low

Examples of how the symbols should be interpreted:

Resource is in good condition; condition is improving; high confidence in the assessment. Resource is in good condition; condition is improving; high confidence in the assessment.
Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment. Condition of resource warrants moderate concern; condition is unchanging; medium confidence in the assessment.
Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment. Condition of resource warrants significant concern; trend in condition is unknown or not applicable; low confidence in the assessment.
Ecosystem Processes Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment.
Indicators of Condition Specific Measures Condition Status/Trend Rationale
Surface Hydrology Channel morphology Significant cause for concern, declining trend, and medium confidence Changes in channel depth and width indicate channel instability when compared to control sites and changes in channel capacity. In 2008, the monument began monitoring six washes bisected by a new pedestrian fence built along the international boundary. The pedestrian fence has caused an accumulation of sediment in adjacent upstream areas, reducing water capacity, and leading to increased flooding and damage to surrounding landscapes.
Natural patterns Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. Water and its movement through the Sonoran Desert determine plant species composition, density, and cover. Monument roads and off-road vehicle traffic have locally degraded infiltration rates (due to increased compaction), increased runoff, blocked, dammed or channelized sheet flow, and diverted natural drainages. These alterations are affecting plant community composition and require mitigation to re-establish natural processes.
Fire Number and size Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. The role of fire in the Sonoran Desert is poorly understood and many plants, such as cacti, are not fire-adapted. The number of fires has risen steadily since 1980 and most are human-caused. Fires have generally been less than one acre, though some recent fires have destroyed historic structures and saguaro cacti. There is a risk of fire at Quitobaquito due to the buildup of dead wood and the monument hopes to be able to conduct fuel load reductions there soon. Brief - Fire
Adjacent Land Use Land-use classification Condition of resource warrants moderate concern; condition is deteriorating; medium confidence in the assessment. Land use is determined from aerial imagery and field work. The conversion of natural lands to agricultural, commercial, and residential use along the international boundary has continued. Adverse impacts include non-native plants and animals, air pollution, fire, groundwater drawdown, illegal entry, and loss of migratory dispersal corridors and native species habitats.
Off-road Motor Vehicle Use Number of vehicle tracks per kilometer of transect sampled Significant cause for concern, declining trend, and medium confidence Impacts from off-road vehicles have increased dramatically in recent years. A decade ago, monitoring revealed approximately 0.5 vehicle impacts per kilometer while in 2011 there were approximately 7.5 vehicle impacts per kilometer. The NPS is currently conducting an assessment of off-road vehicle impacts using a combination of aerial photography and field work. The construction of a vehicle barrier and pedestrian fence in 2006 and 2008 respectively, had the intended effect of nearly eliminating illegal cross-boundary traffic originating from Mexico. Off-road vehicle use has negative impacts on soils, surface hydrology, plant communities, wildlife, cultural resources and wilderness. Brief - Off-road vehicle use
Biological Soil Crusts Percent biocrust cover of soil substrate Condition of resource warrants moderate concern; trend in condition is unknown or not applicable; low confidence in the assessment. Biological soil crusts provide critical ecosystem services in the Sonoran Desert, influencing soil nitrogen availability, soil water holding capacity, and resistance to soil erosion. Preliminary monitoring data indicate that crusts cover 19% of soil surfaces at OPCNM, with very high between site variability. Light cyanobacteria species (inconspicuous crusts that are easily disturbed) comprised 74% of the crust cover.
Vegetation Percent cover Resource is in good condition; condition is unchanging; low confidence in the assessment. Perennial vegetative cover increased from the 1970s, when livestock grazing ended, to the 1980s and again from the 1980s to 1990s. It declined from the 1990s to 2000s. These changes appear to track rainfall with the four sampling efforts following dry, average, wet, and dry periods, respectively. White bursage, an important forage species for Sonoran pronghorn, declined from 6.61 to 0.72% cover between 1994 and 2011 at one site.
Species richness Resource is in good condition; condition is unchanging; low confidence in the assessment. Perennial species richness is up since 1970s and down since 1990s in a pattern similar to that for cover. Drought conditions have prevailed since 1996 and some species may be present but undetected due to the dry conditions during sampling. The Sonoran Desert Network is implementing a new protocol that will resample 60 upland vegetation plots every five years with 12 plots sampled every year.

⇑ To Top of Page

Last Updated: September 03, 2014 Contact Webmaster