Geology topics

Jeffrey S. Hatfield

Publications and source records attributed to Jeffrey S. Hatfield.

13 recordsLinked to original sources

USGS2015

Estimating golden-cheeked warbler immigration: Implications for the spatial scale of conservation

Understanding the factors that drive population dynamics is fundamental to species conservation and management. Since the golden-cheeked warbler S etophaga chrysoparia was first listed as endangered, much effort has taken place to monitor warbler abundance, occupancy, reproduction and survival. Yet, despite being directly related to local population dynamics, movement rates have not been estimated for the species. We used an integrated population model to investigate the relationship between immigration rate, fledging rate, survival probabilities and population growth rate for warblers in central Texas, USA. Furthermore, using a deterministic projection model, we examined the response required by vital rates to maintain a viable population across varying levels of immigration. Warbler abundance fluctuated with an overall positive trend across years. In the absence of immigration, the abundance would have decreased. However, the population could remain viable without immigration if both adult and juvenile survival increased by almost half or if juvenile survival more than doubled. We also investigated the response required by fledging rates across a range of immigration in order to maintain a viable population. Overall, we found that immigration was required to maintain warbler target populations, indicating that warbler conservation and management programs need to be implemented at larger spatial scales than current efforts to be effective. This study also demonstrates that by using limited data within integrated population models, biologists are able to monitor multiple key demographic parameters simultaneously to gauge the efficacy of strategies designed to maximize warbler viability in a changing landscape.

Animal Conservation↗

USGS2014

Age-specific survival of male golden-cheeked warblers on the Fort Hood Military Reservation, Texas

Population models are essential components of large-scale conservation and management plans for the federally endangered Golden-cheeked Warbler ( Setophaga chrysoparia ; hereafter GCWA). However, existing models are based on vital rate estimates calculated using relatively small data sets that are now more than a decade old. We estimated more current, precise adult and juvenile apparent survival (Φ) probabilities and their associated variances for male GCWAs. In addition to providing estimates for use in population modeling, we tested hypotheses about spatial and temporal variation in Φ. We assessed whether a linear trend in Φ or a change in the overall mean Φ corresponded to an observed increase in GCWA abundance during 1992-2000 and if Φ varied among study plots. To accomplish these objectives, we analyzed long-term GCWA capture-resight data from 1992 through 2011, collected across seven study plots on the Fort Hood Military Reservation using a Cormack-Jolly-Seber model structure within program MARK. We also estimated Φ process and sampling variances using a variance-components approach. Our results did not provide evidence of site-specific variation in adult Φ on the installation. Because of a lack of data, we could not assess whether juvenile Φ varied spatially. We did not detect a strong temporal association between GCWA abundance and Φ. Mean estimates of Φ for adult and juvenile male GCWAs for all years analyzed were 0.47 with a process variance of 0.0120 and a sampling variance of 0.0113 and 0.28 with a process variance of 0.0076 and a sampling variance of 0.0149, respectively. Although juvenile Φ did not differ greatly from previous estimates, our adult Φ estimate suggests previous GCWA population models were overly optimistic with respect to adult survival. These updated Φ probabilities and their associated variances will be incorporated into new population models to assist with GCWA conservation decision making.

Texas↗

USGS2014

Preliminary monitoring protocol for the tidal freshwater wetland restoration herbivory study in national capital parks--east: Appendix B

Four tidal freshwater wetland restoration projects have been undertaken within Anacostia Park on lands managed by the National Park Service since 1993. Monitoring the impacts of Canada goose ( Branta canadensis ) herbivory on the wetland vegetation will play a key role in determining the long-term health of these tidal freshwater wetland restorations. This Implementation Plan lays out monitoring for impacts of herbivory on the vegetation in Kingman Area 1 and inferred to the other wetland areas.

Washington, D.C.↗

USGS2013

Spatiotemporal variation in range-wide Golden-cheeked Warbler habitat

Habitat availability ultimately limits the distribution and abundance of wildlife species. Consequently, it is paramount to identify where wildlife habitat is and understand how it changes over time in order to implement large scale wildlife conservation plans. Yet, no work has quantified the degree of change in range-wide breeding habitat for the golden-cheeked warbler (Setophaga chrysoparia), despite the species being listed as endangered by the U.S. federal government. Thus, using available geographic information system (GIS) data and Landsat satellite imagery we quantified range-wide warbler breeding habitat change from 1999-2001 to 2010-2011. We detected a 29% reduction in total warbler breeding habitat and found that warbler breeding habitat was removed and became more fragmented at uneven rates across the warbler’s breeding range during this time period. This information will assist researchers and managers in prioritizing breeding habitat conservation efforts for the species and provide a foundation for more realistic carrying capacity scenarios when modeling golden-cheeked warbler populations over time. Additionally, this study highlights the need for future work centered on quantifying golden-cheeked warbler movement rates and distances in order to assess the degree of connectivity between increasingly fragmented habitat patches.

Texas↗

USGS2013

Demographic variation, reintroduction, and persistence of an island duck ( Anas laysanensis )

Population variation in life history can be important for predicting successful establishment and persistence of reintroduced populations of endangered species. The Laysan duck (Anas laysanensis) is an endangered bird native to the Hawaiian Archipelago that was extirpated from most islands after the introduction of mammalian predators. Laysan ducks were restricted to a single remote island, Laysan Island (4.1 km 2 ), for nearly 150 years. Since the species is not known to disperse between distant Hawaiian Islands today, 42 wild birds from Laysan Island were translocated to another mammalian predator-free low-lying atoll (Midway Atoll; 6.0 km 2 ) to reduce extinction risk. We explored how variation in demography influences establishment and longer-term retention of genetic diversity (rare alleles) for reintroductions of this species. We observed dramatic differences in population growth between the source (λ = 1.18) and reintroduced (λ = 3.28) population. The number of eggs hatched at Midway Atoll was greater than at Laysan Island, however, we found no difference in hatching success (proportion of clutch hatched) between populations. Adult females produced 3 times as many fledglings per breeding year on Midway Atoll compared to Laysan Island. We estimated population abundance of both populations until 2010 and applied a Gompertz model with a Bayesian approach to infer density dependence, process variation, observation error, and carrying capacity for the Laysan Island and Midway Atoll populations. The carrying capacity from the Gompertz model for Midway Atoll (K = 883 ± 210 SD) was estimated to be greater than that of Laysan Island (K = 598 ± 76 SD). Translocations with small numbers of founders and no immigration can create population bottlenecks, leading to loss of genetic variation over time, and potentially reducing the reintroduced population's viability or its potential to serve as a source for future translocations. Therefore, we also assessed the probability of retaining rare alleles in an isolated reintroduced Laysan duck population using life history parameters observed from the Laysan Island and Midway Atoll populations; we concluded that additional founders are needed under scenarios using demographic estimates from both Laysan Island and Midway Atoll to retain either 90% or 95% of source population genetic diversity.

Laysan Island;Midway Atoll↗

USGS2013

Vascular plant and vertebrate species richness in national parks of the eastern United States

Given the estimates that species diversity is diminishing at 50-100 times the normal rate, it is critical that we be able to evaluate changes in species richness in order to make informed decisions for conserving species diversity. In this study, we examined the potential of vascular plant species richness to be used as a surrogate for vertebrate species richness in the classes of amphibians, reptiles, birds, and mammals. Vascular plants, as primary producers, represent the biotic starting point for ecological community structure and are the logical place to start for understanding vertebrate species associations. We used data collected by the United States (US) National Park Service (NPS) on species presence within parks in the eastern US to estimate simple linear regressions between plant species richness and vertebrate richness. Because environmental factors may also influence species diversity, we performed simple linear regressions of species richness versus natural logarithm of park area, park latitude, mean annual precipitation, mean annual temperature, and human population density surrounding the parks. We then combined plant species richness and environmental variables in multiple regressions to determine the variables that remained as significant predictors of vertebrate species richness. As expected, we detected significant relationships between plant species richness and amphibian, bird, and mammal species richness. In some cases, plant species richness was predicted by park area alone. Species richness of mammals was only related to plant species richness. Reptile species richness, on the other hand, was related to plant species richness, park latitude and annual precipitation, while amphibian species richness was related to park latitude, park area, and plant species richness. Thus, plant species richness predicted species richness of different vertebrate groups to varying degrees and should not be used exclusively as a surrogate for vertebrate species richness. Plant species richness should be included with other variables such as area and climate when considering strategies to manage and conserve species in US National Parks. It is not always appropriate to draw conclusions about analyses of taxonomic surrogates from one area to another. Two patterns evident from the linear regressions were the increase in species richness with the increase of park area and with increase of vascular plant species richness. To test whether there were differences in these patterns among networks, we used analysis of covariance (ANCOVA). Differences among networks were detected only in bird species richness versus plant species richness and for all taxa except mammals for vertebrate species richness versus park area. Some of these results may be due to small sample size among networks, and therefore, low statistical power. Other factors that could have contributed to these results were differences in average park area and habitat heterogeneity among networks, latitudinal gradients, low variation in mean annual precipitation, and different use of vegetation by migratory species. Based on these results we recommend that management of biodiversity be approached from local and site specific criteria rather than applying management directives derived from other regions of the US. It is also recommended that analyses similar to those presented here be conducted for all national parks, once data become available for all networks in the US, to gain a better understanding of how vascular plant species richness, area, and vertebrate species richness are related in the US.

Natural Resource Technical Report NPS/NCR/NCRO/NRT↗

USGS2013

Effects of Canada goose herbivory on the tidal freshwater wetlands in Anacostia Park, 2009-2011

Herbivory has played a major role in dictating vegetation abundance and species composition at Kingman Marsh in Anacostia Park, Washington, D.C., since restoration of this tidal freshwater wetland was initiated in 2000. The diverse and robust vegetative cover that developed in the first year post-reconstruction experienced significant decimation in the second year, after the protective fencing was removed, and remained suppressed throughout the five-year study period. In June 2009 a herbivory study was initiated to document the impacts of herbivory by resident and nonmigratory Canada geese (Branta canadensis) to vegetation at Kingman Marsh. Sixteen modules consisting of paired fenced plots and unfenced control plots were constructed. Eight of the modules were installed in vegetated portions of the restoration site that had been protected over time by pre-existing fencing, while the remaining eight modules were placed in portions of the site that had not been protected over time and were basically unvegetated at the start of the experiment. Exclosure fencing was sufficiently elevated from the substrate level to allow access to other herbivores such as fish and turtles, while hopefully excluding mature Canada geese. The study was designed with an initial exclosure elevation of 20 cm. This elevation was chosen based on the literature, as adequate to exclude mature Canada geese, while maximizing access to other herbivores such as fish and turtles. Repeated measures analysis of variance (ANOVA) was used to analyze the differences between paired fenced and unfenced control plots for a number of variables including total vegetative cover. Differences in total vegetative cover were not statistically significant for the baseline data collected in June 2009. By contrast, two months after the old protective fencing was removed from the initially-vegetated areas to allow Canada geese access to the unfenced control plots, total vegetative cover had declined dramatically in the initially-vegetated unfenced control plots, and differences between paired fenced and unfenced control plots were statistically significant. These differences have remained steady and significant throughout the remainder of these first three years of the study. Total vegetative cover has followed a somewhat different path in the initially-unvegetated modules, where cover in the fenced plots did not significantly exceed cover in the unfenced control plots until the August 2010 sampling event. In spite of the slow start in the initially-unvegetated modules, differences between paired fenced plots and unfenced control plots have remained significant and even increased significantly over time. This indicates that total vegetative cover in the initially-unvegetated fenced plots and unfenced control plots is continuing to diverge over time as vegetation increases in the protected plots compared to the basically unvegetated unfenced control plots. Total vegetative cover has been composed almost entirely of native species during the first three years of the study, with cover by exotics averaging less than 1% during each sampling event. Species richness did not differ significantly between fenced plots and unfenced control plots during 2009, the first year of the study. Since August 2010, species richness has remained significantly greater in the fenced plots than in the unfenced control plots. These differences have remained relatively steady over time for both the initially-vegetated and initially unvegetated modules. During the study it became apparent that our elevated fence plots were more accessible to mature geese than we had expected. Even after lowering the exclosure fencing to 15 cm in 2010 and 10 cm in 2011, we documented geese inside exclosures in both years. Nonetheless the data indicate that even at 10 cm, we have limited the numbers of mature geese entering the fenced plots, rather than totally preventing their access through low spots in the uneven substrate surface. At an exclosure elevation of 10 cm and with a soft, mucky substrate, we are assuming that non-goose herbivores such as fish and turtles still have free access to the fenced plots. Annual wildrice (Zizania aquatica), known from previous studies to be especially palatable to Canada geese, has seen the greatest impact from partial access to the fenced plots by mature geese, moving from an overwhelming dominant in the initially-vegetated plots to a minor presence there by August 2011. Interestingly, pickerelweed (Pontederia cordata), also known to be highly palatable to Canada geese, has so far shown only minor herbivory in the fenced plots. By August 2011, pickerelweed had actually increased to significantly greater cover levels in the fenced plots compared to the unfenced control plots. In conclusion, the first three years of data document that vegetation exposed to full herbivory by resident and nonmigratory Canada geese for three years in the unfenced control plots showed significantly lower total vegetative cover and species richness compared to the vegetation in the fenced plots, which experienced reduced herbivory by resident and nonmigratory Canada geese. These effects were documented for modules located in both initially-vegetated and initially-unvegetated habitats.

Maryland↗

USGS2010

Trading off short-term and long-term risk: minimizing the threat of Laysan duck extinction from catastrophes and sea-level rise

Conservation of oceanic island species presents many ecological and logistical challenges. The Northwestern Hawaiian Islands (NWHI) include 300,000 km 2 of ocean waters and 10 groups of sub-tropical islands and atolls of high conservation value. Designated as Papahanaumokuakea Marine National Monument, the islands provide habitat for four endangered species of terrestrial birds. Despite their protected status, many of these species are faced with the ongoing threat of extinction due to stochastic catastrophes such as disease, invasive mammal introductions, tsunamis, and hurricanes. To reduce the risk that a single catastrophe would lead to extinction, managers propose to restore multiple "insurance" populations on islands currently unoccupied by these species to increase their range and overall numbers.

Hawai'i↗

USGS2004

Inter-species variation in yolk steroid levels and a cowbird-host comparison

We examined variability in yolk hormone levels among songbird species and the role of yolk steroids as a mechanism for enhanced exploitation of hosts by the parasitic Brown-headed Cowbird Molothrus ater. Within-clutch variation in yolk steroids has been found in several avian species in single species studies, but few comparisons have been made among species. We found a large range of differences in yolk testosterone among the seven passerine species examined, with significant differences between those at the high end (Song Sparrow Melospiza melodia , Red-winged Blackbird Agelaius phoeniceus, and House Sparrow, Passer domesticus ) and those at the low end (Eastern Phoebe Sayornis phoebe, and House Finch Carpodacus mexicanus ). We also found that the testosterone level in cowbird eggs was intermediate in relation to host species levels and was significantly lower than that in three common cowbird hosts (Song Sparrow, Red-winged Blackbird, and House Sparrow), but not significantly different from three others. Geographical comparisons of yolk testosterone levels in all cowbird subspecies and populations from several regions showed no significant differences, though a trend that deserves further exploration was the pattern of lowest level in the ancestral population of cowbirds in the central prairies and of highest level in the northwestern population where range invasion occurred approximately 40 years ago. The levels of 17 betaestradiol were similar in the seven songbird species examined, which is consistent with current hypotheses that this hormone plays a role in embryonic sexual differentiation. Further investigation is needed to determine whether the large differences observed among species in absolute level of yolk testosterone are the relevant focal point or whether target tissue sensitivity differences mediate the effects of this yolk steroid, particularly between parasitic and non-parasitic species.

Journal of Avian Biology↗

USGS2002

Behavioral effects of environmental enrichment on harbor seals (Phoca vitulina concolor) and gray seals (Halichoerus grypus)

Zoos and aquariums have been incorporating environmental enrichment into their animal care programs for the past 30 years to increase mental stimulation and promote natural behaviors. However, most attempts to document the effects of enrichment on animal behavior have focused on terrestrial mammals. Staff at the National Aquarium in Baltimore conducted an investigation of the behavioral effects of enrichment on the seven harbor seals and two gray seals housed in the aquarium's outdoor seal exhibit. We expected that enrichment would change the amount of time the animals spent engaged in specific behaviors. The behaviors recorded were: resting in water, resting hauled out, maintenance, breeding display, breeding behavior, aggression, pattern swimming, random swimming, exploration, and out of sight. Activity levels (random swimming and exploration) were expected to increase, while stereotypic behaviors (pattern swimming) were expected to decrease. The frequency and duration of behaviors were documented for 90 hr in both the control phase (without enrichment) and the experimental phase (with enrichment). Statistically significant differences ( P <0.05) in the time spent in pattern swimming, random swimming, exploration, and out of sight were observed between the two phases. With enrichment, pattern swimming and out of sight decreased, while random swimming and exploration behavior increased. These findings demonstrate that enrichment can promote behaviors (random swimming and exploration) that are likely to be normal for phocids in the wild, and that may contribute to the behavioral complexity of these seals in captivity.

Zoo Biology↗

USGS2001

Failure of tetracycline as a biomarker in batch-marking juvenile frogs

Recent widespread amphibian declines call for better techniques to assess population dynamics. Tetracycline as a biomarker in capture-recapture studies is one technique used successfully in fish, reptiles, and mammals. A two-phase experimental study was conducted to evaluate tetracycline as a biomarker in green frogs ( Rana clamitans ) and pickerel frogs ( Rana palustris ). In the first experimental phase tadpoles were exposed to water containing either 250 mg/l or 500 mg/l tetracycline for a period of 24 hr. During the second phase, juvenile frogs were exposed to tetracycline in water at 500 mg/l or given injections of tetracycline at the dose rate of 100 mg/kg body weight. At selected times several weeks later, under tricaine methanesulfonate anesthesia, a toe was surgically excised from each animal, sectioned and viewed under an ultraviolet microscope. No significant differences were found between the various treatments and control animals (untreated). Therefore, the use of tetracycline as a biomarker in anurans using these techniques is not recommended.

Journal of Wildlife Diseases↗

USGS1996

Reproductive success, growth and survival of black-crowned night-heron ( Nycticorax nycticorax ) and snowy egret ( Egretta thula ) chicks in coastal Virginia

We studied reproductive success, growth, and survival of Black-crowned Night-Heron ( Nycticorax nycticorax ) and Snowy Egret ( Egretta thula ) chicks in two mixed-species heronries on marsh islands in Chincoteague Bay, Accomack County, Virginia in 1992 and 1993. We attached radio transmitters with mortality sensors to the oldest chicks (A-chicks) in 11 to 22 nests of both species to monitor survival during the mid- to late nestling period and into the postnesting dispersal period. For both species, we found significant differences between 1992 and 1993 in growth rates and survival. Mass growth rates of chicks were higher in 1993 than in 1992 for both species. Culmen-length growth rates varied significantly due to year-colony effects for night-herons, but only for hatching order for egrets. Differences in survival rates due to hatching order were found for the egrets in both years, but were found only in 1992 for night-herons. As with mass growth rates, survival of chicks was higher in 1993 than 1992. Survival of radio-marked A-chicks did not differ between species or years for the period from hatching to fledging or from fledging through the end of the study (ca. two months postfledging). Survival ranged from 0.80 to 1.00 from the time radio transmitters were attached (ca. two weeks of age) until dispersal age (53-55 days for egrets; 55-60 days for night-herons). After birds left the colony, survival rates were lower during the next 40 to 55 days, ranging from 0.25 to 0.60. These results suggest that, at least for Snowy Egrets, A-chicks may be buffered from annual variations in food conditions, but that growth and survival of other brood members may provide a barometer of local conditions. Despite problems of variability in measurement, some of these parameters show promise as bioindicators of estuarine conditions. We recommend that a cost-efficient wading-bird monitoring program would include: (1) estimating numbers of nesting birds of selected species (e.g. Snowy Egrets) at particular estuaries, and (2) monitoring "initial brood sizes" and survival of young to at least two weeks of age in a sample of nests for each focal species. However, additional biomonitoring (e.g. marsh forage fish, contaminant loads) is necessary to evaluate how well top trophic-level organisms such as fish-eating birds respond to changes in estuarine production or quality.

The Auk↗

USGS1991

Lead accumulation and osprey production near a mining site on the Coeur d'Alene River, Idaho

Mining and smelting at Kellogg-Smelterville, Idaho, resulted in high concentrations of lead in Coeur d'Alene (CDA) River sediments 15–65 km downstream, where ospreys ( Pandion haliaetus ) nested. Adult and nestling ospreys living along the CDA River had significantly higher blood lead concentrations than those at Lake Coeur d'Alene (intermediate area) or Pend Oreille and Flathead Lakes (reference areas). Lead concentrations in fish collected from the study areas paralleled those found in ospreys. Inhibition of blood δ-aminolevulinic acid dehydratase (ALAD) activity and elevation of protoporphyrin concentration provided evidence of lead exposure. In adult ospreys, ALAD activity was negatively correlated with lead in blood (r=−0.57), whereas protoporphyrin was positively correlated with lead in blood (r=+0.40). Neither hemoglobin nor hematocrit was adversely affected by the relatively modest lead concentrations found in the blood. Pronounced accumulation of lead by adults or young could ultimately result in behavioral abnormalities or death, both of which would reduce productivity of the nesting osprey population. We did not observe death related to lead, behavioral abnormalities, or reduced productivity during this 1986–87 study. Despite some lead-induced biochemical changes in blood parameters, ospreys produced young at nearly identical rates in the three study areas; these rates were among the highest ever reported in the western United States. Post-fledging survival of ospreys exposed to lead early in life remains an unknown. Lead does not biomagnify in the food chain as do organochlorine pesticides and mercury and several osprey behavior traits reduce the potential for the species to accumulate critical levels of lead. Swans, which feed at a lower trophic level, continue to die from environmental lead in the region.

Idaho↗