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USGS2021

Mangroves and people: Impacts and interactions

Mangroves have long been associated with human populations, as coastal communities rely on the various ecosystem services that mangroves provide. However, human degradation and destruction of mangrove forests is common, despite and because of our reliance on them as valuable ecosystems. Mangrove research and management must elucidate and reconcile these conflicts to maintain mangrove forests and the services that humans depend on. To better understand the complex dynamics, interactions and relationships that exist between mangroves and coastal communities, the 5th Mangrove Macrobenthos and Management (MMM5) conference was held in Singapore in July 2019, with the theme “ Mangroves and People: Impacts and Interactions”. This theme was chosen because Southeast Asia is the epicentre of ongoing mangrove loss, and a large number of coastal communities in the region rely on the ecosystem services that mangroves provide. The 32 papers published in this Special Issue represent the breadth of mangrove research presented at MMM5, including topics in faunal biology, ecosystem ecology, genetics, physical geography, biogeochemistry, remote sensing and the social sciences. The articles are characterized under the following topics: 1) mangrove ecosystem functioning; 2) range expansion of mangroves; 3) ecosystem services of mangroves; 4) anthropogenic and natural threats to mangroves; and 5) the management and social-ecology of mangroves. This Special Issue highlights the current state of the art of mangrove research and application, and describes a number of emerging new ideas and research opportunities that will continue to advance mangrove ecosystem science into the future.

Estuarine, Coastal and Shelf Science↗

USGS2025

The 3D Elevation Program—Supporting Rhode Island’s economy

Introduction High-resolution elevation data are critical to applications of landscape modeling and planning, both of which have a significant effect on Rhode Island’s economy. In these and other enterprises, program managers, while aiming to strike a balance between accuracy and cost, strive to obtain the best available elevation data to help them address a range of issues. Programs focused on climate change, environmental management, transportation design and asset management, aviation navigation and safety, riverine ecosystem management, wildlife habitat characterization and management, shellfish aquaculture, and the management and mapping of forests, parks and recreation areas, soils, wetlands, and impervious surfaces are also among the critical applications that meet the State’s management needs and depend on light detection and ranging (lidar) data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features. The 3D Elevation Program (3DEP) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better to meet the many needs of the Nation and Rhode Island. The status of available and in-progress 3DEP baseline lidar data in Rhode Island is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 ( https://www.usgs.gov/3dep/lidarspec ) or newer requirements. The National Enhanced Elevation Assessment identified user requirements and conservatively estimated that availability of lidar data would result in at least $178,560 in new benefits annually to the State. The top 10 Rhode Island business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Rhode Island↗

USGS2000

Palaeohydrology, vegetation, and climate since the late Illinois Episode (~130 ka) in south-central Illinois

Our interpretation of pollen and ostracode successions from four basins in south-central Illinois provides a new synthesis of palaeovegetation, palaeohydrology, and palaeoclimate for the period from the late Illinois Episode (about 130,000 years ago) to near the end of the Wisconsin Episode (about 25,000 years ago). Correlations of pollen biozones between Raymond, Pittsburg, and Bald Knob basins are the basis for identifying the late Illinois glacial, Sangamon interglacial, Wisconsin glacial, and Hudson interglacial episodes. Glacial episodes were identified primarily by the presence of Picea pollen and the ostracode Limnocythere friabilis, whereas interglacial episodes were identified by Quercus pollen and by the ostracodes Candona caudata and Heterocypris punctata. Within interglacial and glacial episodes, pollen and ostracode assemblages varied with changes in moisture balance. Local palaeohydrology was assessed primarily on the basis of environmental tolerance indices of ostracodes and the stable isotope (C,O) stratigraphy of ostracodal calcite. Regional moisture balance was assessed from multivariate analyses of the pollen successions. Three climatic regimes occurred during the Sangamon Episode. (1) One regime was characterised by precipitation exceeding evaporation that promoted basin overflow. This climate was inferred from the high percentages (generally >80%) of deciduous-forest pollen. Peaks in the abundance of Liquidambar and Fagus pollen indicate that winters may have been slightly warmer, and effective moisture slightly greater, than at present. (2) The second climatic regime was continental, similar to the present climate of Illinois in which precipitation is equal to or just less than evaporation. This climate is inferred from abundant Ambrosia pollen (40 to 60%) and abundant nektic (swimming) ostracode valves which suggest a shallow lake. These conditions probably developed in association with a 'heat-low' over the interior of North America during marine oxygen isotope stages 5e and 5c. Associated with the transition between the first two climates are fossils of the subtropical ostracode Heterocypris punctata and the giant tortoise Geochelone crassiscutata that suggest short periods in winter when polar low-pressure systems did not extend into Illinois as they do today. (3) The third climatic regime occurred during the transition from the Sangamon interglacial episode to the Wisconsin glacial episode. A severely continental climate is indicated by the heat-tolerant ostracode Pelocypris tuberculatum, variable ??18O values of ostracode valves, and high environmental tolerance index values for the ostracode assemblages. The weedy Chenopodiaceae and Amaranthaceae families grew on exposed mudflats. The tree pollen associated with this type of climate included low percentages of Picea and Liquidambar, an assemblage that has no modem analogue. We suggest that this transitional climatic regime was associated with the large-scale changes in the climate system during marine oxygen isotope stage 4.

Conference Paper↗

USGS2010

Interfacing models of wildlife habitat and human development to predict the future distribution of puma habitat

The impact of human land uses on ecological systems typically differ relative to how extensively natural conditions are modified. Exurban development is intermediate-intensity residential development that often occurs in natural landscapes. Most species-habitat models do not evaluate the effects of such intermediate levels of human development and even fewer predict how future development patterns might affect the amount and configuration of habitat. We addressed these deficiencies by interfacing a habitat model with a spatially-explicit housing-density model to study the effect of human land uses on the habitat of pumas ( Puma concolor ) in southern California. We studied the response of pumas to natural and anthropogenic features within their home ranges and how mortality risk varied across a gradient of human development. We also used our housing-density model to estimate past and future housing densities and model the distribution of puma habitat in 1970, 2000, and 2030. The natural landscape for pumas in our study area consisted of riparian areas, oak woodlands, and open, conifer forests embedded in a chaparral matrix. Pumas rarely incorporated suburban or urban development into their home ranges, which is consistent with the hypothesis that the behavioral decisions of individuals can be collectively manifested as population-limiting factors at broader spatial scales. Pumas incorporated rural and exurban development into their home ranges, apparently perceiving these areas as modified, rather than non-habitat. Overall, pumas used exurban areas less than expected and showed a neutral response to rural areas. However, individual pumas that selected for or showed a neutral response to exurban areas had a higher risk of mortality than pumas that selected against exurban habitat. Exurban areas are likely hotspots for puma-human conflict in southern California. Approximately 10% of our study area will transform from exurban, rural, or undeveloped areas to suburban or urban by 2030, and 35% of suitable puma habitat on private land in 1970 will have been lost by 2030. These land-use changes will further isolate puma populations in southern California, but the ability to visualize these changes had provided a new tool for developing proactive conservation solutions.

California↗

USGS2016

Evaluating detection and monitoring tools for incipient and relictual non-native ungulate populations

Hawai‘i Volcanoes National Park (HAVO) encompasses 1,308 km2 on Hawai‘i Island. The park harbors endemic plants and animals which are threatened by a variety of invasive species. Introduced ungulates have caused sharp declines of numerous endemic species and have converted ecosystems to novel grazing systems in many cases. Local ranchers and the Territorial Government of Hawai‘i had long conducted regional ungulate control even prior to the establishment of HAVO in 1916. In 1995 the park’s hunting team began a new hunt database that allowed managers to review hunt effort and effectiveness in each management unit. Target species included feral pigs (Sus scrofa), European mouflon sheep (Ovis gmelini musimon), feral goats (Capra hircus) and wild cattle (Bos taurus). Hunters removed 1,204 feral pigs from HAVO over a 19-year period (1996‒2014). A variety of methods were employed, but trapping, snaring and ground hunts with dogs accounted for the most kills. Trapping yielded the most animals per unit effort. Hunters and volunteers removed 6,657 mouflon from HAVO; 6,601 of those were from the 468 km2 Kahuku Unit. Aerial hunts yielded the most animals followed by ground hunt methods. Hunters completed eradications of goats in several management units over an 18- year period (1997‒2014) when they removed the last 239 known individuals in HAVO primarily with aerial hunts. There have also been seven cattle and five feral dogs (Canis familiaris) removed from HAVO. Establishing benchmarks and monitoring the success of on-the-ground ungulate removal efforts can improve the efficiency of protecting and restoring native forest for high-priority watersheds and native wildlife. We tested a variety of methods to detect small populations of ungulates within HAVO and the Hō‘ili Wai study area in the high-priority watershed of Ka‘ū Forest Reserve on Hawai‘i Island. We conducted ground surveys, aerial surveys and continuous camera trap monitoring in both fence-enclosed units and unenclosed units where populations of introduced mouflon and feral pigs threatened sensitive native plants and forest bird habitats. Beginning in June 2014, twenty infrared camera traps were positioned in areas occupied by ungulates. The cameras were active for at most 198 days, and then half of the cameras were baited with oats and salt blocks for 126 days. There were a total of 1,496 observations of mouflon captured on camera, totaling 2,592 individuals: 1,020 ewes, 900 rams, 276 lambs, and 396 sheep of unknown sex. There were no detections of the illegally introduced axis deer (Axis axis). There were 11 observations of feral pigs and 109 observations of other animals (birds, rats, and other small mammals), including one detection of the federally endangered Hawaiian hawk (Buteo solitarius). Mouflon detection rates did not increase near baited cameras until three months after the initial baiting. Ground-based surveys for ungulate presence were conducted along six transects in Kahuku in October 2014. Evidence of ungulates were detected in 27.5% of plots surveyed within an unenclosed unit, while an enclosed unit had sign in only 3.6% of plots surveyed. An aerial survey by helicopter was conducted in October 2014. A total of 378 mouflon were detected during the survey: 192 in the Kahuku Paddocks, 186 in the Kahuku East unit and no mouflon were detected in the actively controlled Mauka unit. Two baseline ungulate surveys have been completed at the Hō‘ili Wai study area in the highpriority watershed of Ka‘ū Forest Reserve adjacent to Kahuku prior to the completion of an exclusionary ungulate fence. Ground-based surveys were conducted on four transects within a 4.99 km2 area on 5 August and 5–6 November 2014. In August, 20.71% of 565 plots surveyed 2 had fresh or intermediate ungulate sign. In November, 17.41% of 557 plots surveyed had fresh or intermediate ungulate sign. These surveys represent baseline levels of ungulate activity prior to management; therefore comparative inferences can be made about ungulate distribution and relative abundance, but inferences about absolute abundance cannot be made until all ungulates have been removed from the enclosed area. Additional ground-based surveys will be conducted when the fenced area has been fully enclosed, and until ungulate removals have been completed.

Hawaii↗

USGS2013

Nutrient concentrations in surface water and groundwater, and nitrate source identification using stable isotope analysis, in the Barnegat Bay-Little Egg Harbor watershed, New Jersey, 2010–11

Five streams in the Barnegat Bay-Little Egg Harbor (BB-LEH) watershed in southern New Jersey were sampled for nutrient concentrations and stable isotope composition under base-flow and stormflow conditions, and during the growing and nongrowing seasons, to help quantify and identify sources of nutrient loading. Samples were analyzed for concentrations of total nitrogen, ammonia, nitrate plus nitrite, organic nitrogen, total phosphorus, and orthophosphate, and for nitrogen and oxygen stable isotope ratios. Concentrations of total nitrogen in the five streams appear to be related to land use, such that streams in subbasins characterized by extensive urban development (and historical agricultural land use)—North Branch Metedeconk and Toms Rivers—exhibited the highest total nitrogen concentrations (0.84–1.36 milligrams per liter (mg/L) in base flow). Base-flow total nitrogen concentrations in these two streams were dominated by nitrate; nitrate concentrations decreased during storm events as a result of dilution by storm runoff. The two streams in subbasins with the least development—Cedar Creek and Westecunk Creek—exhibited the lowest total nitrogen concentrations (0.16–0.26 mg/L in base flow), with organic nitrogen as the dominant species in both base flow and stormflow. A large proportion of these subbasins lies within forested parts of the Pinelands Area, indicating the likelihood of natural inputs of organic nitrogen to the streams that increase during periods of storm runoff. Base-flow total nitrogen concentrations in Mill Creek, in a moderately developed basin, were 0.43 to 0.62 mg/L and were dominated by ammonia, likely associated with leachate from a landfill located upstream. Total phosphorus and orthophosphate were not found at detectable concentrations in most of the surface-water samples, with the exception of samples collected from the North Branch Metedeconk River, where concentrations ranged from 0.02 to 0.09 mg/L for total phosphorus and 0.008 to 0.011 mg/L for orthophosphate. Measurements of nitrogen and oxygen stable isotope ratios of nitrate in surface-water samples revealed that a mixture of multiple subsurface sources, which may include some combination of animal and septic waste, soil nitrogen, and commercial fertilizers, likely contribute to the base-flow nitrogen load. The results also indicate that atmospheric deposition is not a predominant source of nitrogen transported to the BB-LEH estuary from the watershed, although the contribution of nitrate from the atmosphere increases during stormflow. Atmospheric deposition of nitrate has a greater influence in the less developed subbasins within the BB-LEH watershed, likely because few other major sources of nitrogen (animal and septic waste, fertilizers) are present in the less developed subbasins. Atmospheric sources appear to contribute proportionally less of the overall nitrate as development increases within the BB-LEH watershed. Groundwater samples collected from five wells located within the BB-LEH watershed and screened in the unconfined Kirkwood-Cohansey aquifer system were analyzed for nutrient and stable isotope composition. Concentrations of nitrate ranged from not detected to 3.63 mg/L, with the higher concentrations occurring in the highly developed northern portion of the watershed, indicating the likelihood of anthropogenic sources of nitrogen. Isotope data for the two wells with the highest nitrate concentrations are more consistent with fertilizer sources than with animal or septic waste. Total phosphorus was not detected in any of the wells sampled, and orthophosphate was either not detected or measured at very low concentrations (0.005–0.009 mg/L) in each of the wells sampled.

New Jersey↗

USGS2013

Protocol for monitoring forest-nesting birds in National Park Service parks

These documents detail the protocol for monitoring forest-nesting birds in National Park Service parks in the National Capital Region Network (NCRN). In the first year of sampling, counts of birds should be made at 384 points on the NCRN spatially randomized grid, developed to sample terrestrial resources. Sampling should begin on or about May 20 and continue into early July; on each day the sampling period begins at sunrise and ends five hours later. Each point should be counted twice, once in the first half of the field season and once in the second half, with visits made by different observers, balancing the within-season coverage of points and their spatial coverage by observers, and allowing observer differences to be tested. Three observers, skilled in identifying birds of the region by sight and sound and with previous experience in conducting timed counts of birds, will be needed for this effort. Observers should be randomly assigned to ‘routes’ consisting of eight points, in close proximity and, ideally, in similar habitat, that can be covered in one morning. Counts are 10 minutes in length, subdivided into four 2.5-min intervals. Within each time interval, new birds (i.e., those not already detected) are recorded as within or beyond 50 m of the point, based on where first detected. Binomial distance methods are used to calculate annual estimates of density for species. The data are also amenable to estimation of abundance and detection probability via the removal method. Generalized linear models can be used to assess between-year changes in density estimates or unadjusted count data. This level of sampling is expected to be sufficient to detect a 50% decline in 10 years for approximately 50 bird species, including 14 of 19 species that are priorities for conservation efforts, if analyses are based on unadjusted count data, and for 30 species (6 priority species) if analyses are based on density estimates. The estimates of required sample sizes are based on the mean number of individuals detected per 10 minutes in available data from surveys in three NCRN parks. Once network-wide data from the first year of sampling are available, this and other aspects of the protocol should be re-assessed, and changes made as desired or necessary before the start of the second field season. Thereafter, changes should not be made to the field methods, and sampling should be conducted annually for at least ten years. NCRN staff should keep apprised of new analytical methods developed for analysis of point-count data.

Report↗

USGS2004

Total mercury and methylmercury in fish fillets, water, and bed sediments from selected streams in the Delaware River basin, New Jersey, New York, and Pennsylvania, 1998-2001

Within the Delaware River Basin, fish-tissue samples were analyzed for total mercury (tHg). Water and bed-sediment samples were analyzed for tHg and methylmercury (MeHg), and methylation efficiencies were calculated. This study was part of a National Mercury Pilot Program conducted by the U.S. Geological Survey (USGS). The Delaware River Basin was chosen because it is part of the USGS National Water-Quality Assessment Program that integrates physical, chemical, and biological sampling efforts to determine status and trends in surface-water and ground-water resources. Of the 35 sites in the study, 31 were sampled for fish. The species sampled at these sites include smallmouth bass (Micropterus dolomieu), the target species, and where smallmouth bass could not be collected, brown trout (Salmo trutta), chain pickerel (Esox niger), largemouth bass (Micropterus salmoides), and rock bass (Ambloplites rupestris). There were a total of 32 fish samples; 7 of these exceeded the 0.3 microgram per gram wet-weight mercury (Hg) concentration set for human health by the U.S. Environmental Protection Agency and 27 of these exceeded the U.S. Fish and Wildlife Service criteria of 0.1 microgram per gram wet weight for the protection of fish-eating birds and wildlife. Basinwide analysis of Hg in fish, water, and bed sediment showed tHg concentration in fillets correlated positively with population density, urban land cover, and impervious land surface. Negative correlations included wetland land cover, septic density, elevation, and latitude. Smallmouth bass from the urban sites had a higher median concentration of tHg than fish from agricultural, low intensity-agricultural, or forested sites. Concentrations of tHg and MeHg in water were higher in samples from the more urbanized areas of the basin and were positively correlated with urbanization and negatively correlated with forested land cover. Methylation efficiency of water was negatively correlated with urbanization. Bed-sediment patterns were similar to those observed in water. Concentrations of tHg were higher in samples from the urbanized areas. In the more forested areas, MeHg concentrations were higher than in other land-use areas. Concentrations of tHg in bed sediment were positively correlated with urbanization factors (population, urban land cover, and impervious land surface) and negatively correlated with forested land cover and elevation. Forested land cover and latitude were positively correlated with concentrations of MeHg. The methylation efficiency was higher in samples from the forested areas and was negatively correlated with urbanization. Analyses within land-use groups showed that tHg concentrations in fish fillets from the urban sites were positively correlated with forested land cover and wetland cover. Urbanization factors within the agricultural group were positively correlated with tHg in fish; concentrations of tHg in fish from sites in the low intensity-agricultural group were negatively correlated with urbanization factors. Within the agricultural land-use group, tHg concentrations in water were negatively correlated with septic density, and MeHg concentrations were negatively correlated with elevation. In the forested and low intensity-agricultural groups, MeHg in water was negatively correlated with forested and agricultural land cover. Methylation efficiency in water also was negatively correlated with forested land cover but positively correlated with agricultural land cover. Bed-sediment concentrations of tHg in the forested and low-agricultural groups were positively correlated with agricultural land cover and negatively correlated with forested land cover. Concentrations of MeHg in bed sediment were positively correlated with septic density and drainage area and negatively correlated with forested land cover. Methylation efficiency was negatively correlated with population density, agricultural land cover, and sulfate concentrations in water. An urbanization effect was observed in all three media—fish, water, and bed sediment. Different factors, basinwide and within land-use groups, showed a complex relation. Additional sampling within these land-use groups could help characterize interrelations of Hg in the environment to fish in the Delaware River Basin.

New Jersey, New York, Pennsylvania↗

USGS2015

Ants of the national park of American Samoa

American Samoa makes up the eastern end of the Samoan Archipelago. On the islands of Tutuila, Taʽū and Ofu, the National Park of American Samoa (NPSA) protects about 4,000 ha of coastal, mid-slope and ridge-top forest. While the ant fauna of the Samoan Archipelago is considered relatively well documented, much of NPSA has never been surveyed for ants, leaving the fauna and its distribution poorly known. To address this shortfall, we systematically surveyed ants within the Tutuila and Taʽū units of NPSA using standard methods (hand collecting, litter sifting, and baits) at 39 sites within six vegetation types ranging from 8 to 945 m elevation. Forty-four ant species were identified, 19 of which are exotic to the Samoan Archipelago. Two notoriously aggressive species, Anoplolepis gracilipes and Pheidole megacephala were detected at two and seven sites, respectively. Both of these species largely excluded all other ants from bait, although their impact on ant community composition is unclear. A suite of habitat variables measured at each site was assessed to explain park-wide ant distributions. Of eight variables evaluated, only elevation was associated with ant community structure, as the ratio of native to exotic ant species increased significantly with elevation on Tutuila. Our survey documented two species not previously reported from American Samoa. Strumigenys eggersi, detected at 12 sites, appears to be a new immigrant to the Pacific Basin. A species of Pheidole was collected that likely represents an undescribed species. Solenopsis geminata, an aggressive species first reported on Tutuila in 2002, was not detected during our survey.

America Samoa↗

USGS2016

Elevated Rocky Mountain elk numbers prevent positive effects of fire on quaking aspen ( Populus tremuloides ) recruitment

Quaking aspen ( Populus tremuloides ) is the most widespread tree species in North America and has supported a unique ecosystem for tens of thousands of years, yet is currently threatened by dramatic loss and possible local extinctions. While multiple factors such as climate change and fire suppression are thought to contribute to aspen’s decline, increased browsing by elk ( Cervus elaphus ), which have experienced dramatic population increases in the last &sim;80 years, may severely inhibit aspen growth and regeneration. Fires are known to favor aspen recovery, but in the last several decades the spatial scale and intensity of wildfires has greatly increased, with poorly understood ramifications for aspen growth. Here, focusing on the 2000 Cerro Grande fire in central New Mexico – one of the earliest fires described as a “mega-fire” - we use three methods to examine the impact of elk browsing on aspen regeneration after a mega-fire. First, we use an exclosure experiment to show that aspen growing in the absence of elk were 3× taller than trees growing in the presence of elk. Further, aspen that were both protected from elk and experienced burning were 8.5× taller than unburned trees growing in the presence of elk, suggesting that the combination of release from herbivores and stimulation from fire creates the largest aspen growth rates. Second, using surveys at the landscape level, we found a correlation between elk browsing intensity and aspen height, such that where elk browsing was highest, aspen were shortest. This relationship between elk browsing intensity and aspen height was stronger in burned ( r = −0.53) compared to unburned ( r = −0.24) areas. Third, in conjunction with the landscape-level surveys, we identified possible natural refugia, microsites containing downed logs, shrubs etc. that may inhibit elk browsing by physically blocking aspen from elk or by impeding elk’s ability to move through the forest patch. We did not find any consistent patterns between refuge elements and aspen size or canopy cover suggesting that natural refugia are not aiding in aspen recruitment and that all young aspen were susceptible to browsing. In much of their normal range, aspen are not growing to large size classes, which threatens the future of this iconic species and calls into question the ability of ecosystems to recover from mega-fires. Our results highlight the importance of considering multiple interacting factors (i.e. fire and increased elk browsing) when considering aspen management and regeneration.

New Mexico↗

USGS2026

Final project peport for “Mapping riparian vegetation response to climate change on the San Carlos Apache Reservation and Upper Gila River watershed to inform restoration priorities: 1935 to present – Phase 2: Focus on tamarisk vegetation”

Riparian ecosystems play a critical role in supporting wildlife habitats, maintaining water quality, and sustaining ecological resilience in arid landscapes. In the Upper Gila River level-4 Hydrologic Unit Code (HUC-4; Identification Number – 1504) watershed of Arizona and New Mexico, and across areas of the San Carlos Apache Tribe of the San Carlos Apache Reservation (hereafter, Tribe/Tribal – entity; or Reservation - place), riparian ecosystems have been substantially altered by the widespread expansion of tamarisk ( Tamarix spp.), an invasive and non-native riparian species. Tamarisk has high water use and increased flammability, making it a growing concern as droughts intensify across the southwestern United States (U.S.). Recent research indicates that tamarisk is increasingly stressed under prolonged drought conditions, which can elevate wildfire risk and further degrade riparian habitat. In response, the U.S. Geological Survey (USGS) Western Geographic Science Center, in collaboration with the Tribe, developed remote sensing–based tools to map riparian vegetation composition and monitor vegetation condition over time. These tools enable accurate identification of tamarisk extent, detection of vegetation stress, and comparison with native species such as cottonwood and willow. This information directly supports restoration and management actions, including targeted tamarisk removal, protection of endangered species habitat, and prioritization of areas for native vegetation recovery. The tools also provide insight into how riparian vegetation responds to changing climate and hydrologic conditions, strengthening long-term planning for riparian forest management. Findings from this work demonstrate that riparian vegetation responses vary across river systems, indicating differences in plant composition and hydro-climatic conditions. Tamarisk on both the Gila and San Carlos Rivers generally exhibit greater declines in greenness in response to higher temperature as well as lower precipitation and river flow, while cottonwood ( Populus fremontii ) and willow (Salix spp.) are particularly sensitive to changes in discharge along the San Carlos River and respond more directly to both high and low flows, with more moderate responses to precipitation and temperature. By providing actionable, science-based information, this research supports climate adaptation planning, wildfire risk reduction, and improved riparian ecosystem health, with benefits that extend beyond the Reservation to regional water and wildlife conservation efforts.

Arizona, New Mexico↗

USGS2010

Mercury and methylmercury dynamics in a coastal plain watershed, New Jersey, USA

The upper Great Egg Harbor River watershed in New Jersey's Coastal Plain is urbanized but extensive freshwater wetlands are present downstream. In 2006-2007, studies to assess levels of total mercury (THg) found concentrations in unfiltered streamwater to range as high as 187 ng/L in urbanized areas. THg concentrations were <20 ng/L in streamwater in forested/wetlands areas where both THg and dissolved organic carbon concentrations tended to increase while pH and concentrations of dissolved oxygen and nitrate decreased with flushing of soils after rain. Most of the river's flow comes from groundwater seepage; unfiltered groundwater samples contained up to 177 ng/L of THg in urban areas where there is a history of well water with THg that exceeds the drinking water standard (2,000 ng/L). THg concentrations were lower (<25 ng/L) in unfiltered groundwater from downstream wetland areas. In addition to higher THg concentrations (mostly particulate), concentrations of chloride were higher in streamwater and groundwater from urban areas than in those from downstream wetland areas. Methylmercury (MeHg) concentrations in unfiltered streamwater ranged from 0.17 ng/L at a forest/wetlands site to 2.94 ng/L at an urban site. The percentage of THg present as MeHg increased as the percentage of forest + wetlands increased, but also was high in some urban areas. MeHg was detected only in groundwater <1 m below the water/sediment interface. Atmospheric deposition is presumed to be the main source of Hg to the wetlands and also may be a source to groundwater, where wastewater inputs in urban areas are hypothesized to mobilize Hg deposited to soils. ?? 2010 US Government.

Water, Air, & Soil Pollution↗

USGS2025

2022 McKinney rain-on-wildfire event, dissolved oxygen sags, and a fish kill on the Klamath River, California

The longitudinal propagation of water-quality and ecological impairments in rivers during and after wildfires remain poorly understood. In Northern California, the 2022 McKinney Fire burned 243 km 2 of the Klamath National Forest, with 83% of the burned area classified as moderate to high severity. During the active wildfire, a high-intensity monsoonal rain event triggered sediment-laden flooding and runoff-initiated debris flows, causing extreme water-quality impairments and a 95 km fish kill zone along the main-stem Klamath River. This rain-on-wildfire event produced a flood wave that outpaced a sediment pulse, diminishing the dilution effect of the floodwaters. A network of high-frequency water-quality sensors recorded water-quality impairments that propagated 296 km downstream. Impairments at the nearest monitoring station, situated 71 km downstream from the fire perimeter, included dissolved oxygen sags to zero (anoxia) for 5.25 h, turbidity spikes exceeding 1000 FNU, a doubling of specific conductance from 175 to 415 µS/cm (at 25 °C), and pH anomalies of 0.5 units from 7.8 to 7.3. This novel rain-on-wildfire event triggered the first flush of fire-scar material during an active wildfire, resulting in water-quality impairments unprecedented in the historical monitoring data for the river spanning 2012 to 2022. This study provides new insights into the potential role of rain-on-wildfire events in generating extreme downstream water-quality and ecological impairments in a more fire-prone future.

California, Oregon↗

USGS2012

Status and limiting factors of two rare plant species in dry montane communities of Hawai`i Volcanoes National Park.

Two rare plants native to montane dry forests and woodland communities of Hawai`i Volcanoes National Park (HAVO) were studied for more than two years to determine their stand structure, short-term mortality rates, patterns of reproductive phenology, success of fruit production, floral visitor composition, seed germination rates in the greenhouse, and survival of both natural and planted seedlings. Phyllostegia stachyoides , a shrubby Hawaiian mint (Lamiaceae) that is a species of concern, was studied within two small kīpuka at a natural population on the park’s Mauna Loa Strip, and three plantings at sites along the Mauna Loa Road were also monitored. Silene hawaiiensis , a threatened shrub species in the pink family (Caryophyllaceae), was monitored at two natural populations, one on Mauna Loa at the Three Trees Kīpuka and the second on Kīlauea Crater Rim south of Halema`uma`u. Silene hawaiiensis plantings were also made inside and outside ungulate exclosures at the park’s Kahuku Unit Phyllostegia stachyoides appeared to have a relatively stable natural population in HAVO with approximately 19% adult plant mortality over three years and recruitment of natural seedlings. Despite high mortality (~98%), some seedlings persisted for more than a year, and recruitment of new plants into the population exceeded the losses of adult plants. Flowering and fruiting phenology was annual and seasonal with peak appearance of buds and flowers in spring and greatest abundance of mature fruit in the summer and fall. Successful production of green fruit from buds and flowers was very high (45%), and green fruit transitioned to mature fruit at a rate of 17.8%. Five insect species were observed visiting flowers, and those with the greatest visitation rates were the alien hover fly Allograpta obliqua (Syrphidae) and the endemic yellowfaced bee Hylaeus difficilis (Colletidae). Both insect species were shown to be carrying pollen of P. stachyoides . Seed germination rates in the greenhouse were variable but ranged as high as 80.4%. Mortality of seedlings planted at three sites along the Mauna Loa Road was very high (~90%) within 2–3 years of planting. There was no significant difference in the mortality or growth of seedlings planted in areas with little grass compared to those in adjacent areas with high grass cover. Silene hawaiiensis had a stable population structure at the Mauna Loa study area, but its population structure at the Kīlauea study site was flat to declining. Mortality of adult plants was low on Mauna Loa (6.5%), but was greater than 30% at the Kīlauea Crater Rim site. Among regularly monitored plants at the Kīlauea site, losses were observed in all size classes between 2006 and 2008. Natural seedling recruitment was observed in stand structure plots at both sites between 2006 and 2007, but numbers of seedlings were low and did not compensate for losses of adult plants. Reproductive phenology was annual with buds and flowers observed in summer and fall, and fruit formed in the fall and winter. The production of immature fruit capsules from buds and flowers was high (51.2%) and tagged immature fruit became mature fruit at a high rate of 66.7%. Floral visitation rates were very low in timed observations and only three insect species were identified visiting S. hawaiiensis flowers: native yellow-faced bees Hylaeus difficilis and H. volcanicus , and the alien hover fly Allograpta exotica . A seed dispersal experiment at the Kīlauea Crater Rim site demonstrated that wind dispersed seeds could travel at least 40 m from S. hawaiiensis plants with mature open capsules. Seed germination rates varied from 7.0 to 73.0% in greenhouse trials. Mortality of planted seedlings at Kahuku was not significantly greater outside ungulate exclosures than inside, but growth in height and production of reproductive structures was significantly greater in protected areas inside exclosures. In the current study, the seedling stage was the most vulnerable part of the life cycle for both P . stachyoides and S. hawaiiensis , and low seedling recruitment appeared to be the most important limiting factor for these species

Hawaii↗

USGS2013

The 3D Elevation Program: summary for Alabama

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of Alabama, elevation data are critical for flood risk management; infrastructure and construction management; wildfire management, planning, and response; natural resources conservation; geologic resource assessment and hazards mitigation; and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios. The new 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A-16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation’s natural and constructed features.

Alabama↗

USGS2014

The 3D Elevation Program: summary for Montana

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of Montana, elevation data are critical for flood risk management, infrastructure and construction management, agriculture and precision farming, geologic resource assessment and hazard mitigation, natural resources conservation, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, Tribal, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios. The new 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A–16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation’s natural and constructed features.

Montana↗

USGS2013

The 3D Elevation Program: summary for Florida

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of Florida, elevation data are critical for natural resources conservation; flood risk management; infrastructure and construction management; coastal zone management; sea level rise and subsidence; wildfire management, planning, and response; and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios.The new 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey, the OMB Circular A–16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation’s natural and constructed features.

Florida↗

USGS2022

Research to inform passage spacing for migratory amphibians and to evaluate efficacy and designs for open elevated road segment (ERS) passages

This is a multifaceted project that includes three main areas of research targeted to inform effective crossing systems for migratory amphibians, a large group of species which are at very high risk from negative impacts from roads within their habitats (Glista et al. 2008, Hamer and McDonnell 2008, Semlitsch 2008, Brehme et al. 2018). The three projects presented in this report are: 1) Movement distances along road barrier fencing and probabilities of reaching a passage: Case study with Yosemite toads in Sierra National Forest, CA. 2) Effectiveness of a novel elevated road segment (ERS) road passage system prototype in providing connectivity for amphibians, reptiles, and small mammals: Case study in Sierra National Forest, CA. 3) Concept designs and transportation engineering evaluation for the ERS on primary roads and highways. This research began in 2018 as part of a larger U.S. Geological Survey (USGS) research program in collaboration with the U.S. Forest Service (USFS), California Department of Transportation (Caltrans), and Western Transportation Institute (WTI; Montana State University) to inform best management practices for barrier and crossing systems for sensitive amphibians and reptiles in California (Langton and Clevenger 2021, Brehme and Fisher 2020). The funding from Department of Transportation (DOT) pooled fund partners (Parks Canada / Government of Canada, Federal Highway Administration (FHWA), U.S. State Departments of Transportation (AK, AZ, CA, CO, IA, MI, MN, NM, NV, OR, WA), Ontario Ministry of Transportation) and managed by the Nevada Department of Transportation (NDOT) supported 2021 field study efforts, analyses of fence movement distances for Yosemite toads, and analysis of the efficacy of a novel ERS passage system to Yosemite toads and other amphibians, reptiles and small mammals. Finally, this pooled fund project includes an assessment by transportation engineers in consultation with USGS and Caltrans to provide insight, guidance, and concept designs for similar crossing solutions that could be implemented on improved roads. This research is meant to inform the distances required between crossings to provide permeability for migratory amphibians (i.e., to allow movements necessary for population persistence across roads) as well as to assess the permeability of a new passage design for amphibians and other small animal species that may provide greater connectivity and offer an alternative to below grade tunnels. The results of these studies add to the current body of knowledge in road ecology and increase the choices of road passage designs for amphibians and other small wildlife species.

California↗