Geology topics

Jordan Raphael

Publications and source records attributed to Jordan Raphael.

6 recordsLinked to original sources

USGS2023

Deer management generally reduces densities of nymphal Ixodes scapularis, but not prevalence of infection with Borrelia burgdorferi sensu stricto

Human Lyme disease–primarily caused by the bacterium Borrelia burgdorferi sensu stricto (s.s.) in North America–is the most common vector-borne disease in the United States. Research on risk mitigation strategies during the last three decades has emphasized methods to reduce densities of the primary vector in eastern North America, the blacklegged tick ( Ixodes scapularis ). Controlling white-tailed deer populations has been considered a potential method for reducing tick densities, as white-tailed deer are important hosts for blacklegged tick reproduction. However, the feasibility and efficacy of white-tailed deer management to impact acarological risk of encountering infected ticks (namely, density of host-seeking infected nymphs; DIN) is unclear. We investigated the effect of white-tailed deer density and management on the density of host-seeking nymphs and B. burgdorferi s.s. infection prevalence using surveillance data from eight national parks and park regions in the eastern United States from 2014–2022. We found that deer density was significantly positively correlated with the density of nymphs (nymph density increased by 49% with a 1 standard deviation increase in deer density) but was not strongly correlated with the prevalence of B. burgdorferi s.s. infection in nymphal ticks. Further, while white-tailed deer reduction efforts were followed by a decrease in the density of I. scapularis nymphs in parks, deer removal had variable effects on B. burgdorferi s.s. infection prevalence, with some parks experiencing slight declines and others slight increases in prevalence. Our findings suggest that managing white-tailed deer densities alone may not be effective in reducing DIN in all situations but may be a useful tool when implemented in integrated management regimes.

Maryland, Pennsylvania, Virginia, West Virginia↗

USGS2019

A rapid assessment method for ground layer coastal vegetation

We aim to test a rapid ecological assessment method to monitor regenerating coastal vegetation without sacrificing accuracy. We estimated species frequency in vegetation plots using traditional point intercept methods. We also tested a rapid, digital method to take high-resolution digital photographs of plots. We navigated among plot locations using a sub-meter Differential Global Positioning System instead of using permanent plot markers, and analyzed plot photographs in a point intercept manner (i.e., grid) in Geographic Information Systems software. We assessed species frequency in 52 permanent plots using traditional and digital methods. Traditional methods required 39.2 min per plot and digital methods required 4.6 min per plot. Estimates of frequency from traditional methods were substantially higher than those from digital methods for permanent plots, so we used an independent assessment of vegetation coverage to calibrate the utility of digital methods. A logistic regression equation can be used to compare historical traditional estimates to those collected digitally. Digital point intercept methods were successfully used for rapid ecological assessment. The primary advantages of digital methods include overwhelming efficiency compared to traditional methods, a resultant increase in sample size, and the ability to recover more accurate estimates of species frequency. Disadvantages of digital methods include a restriction of use for ground layer vegetation and positional inaccuracies introduced through sub-meter navigation. While traditional methods are less accurate in estimating species frequency, they are ideal for capturing accurate temporal trends in vegetation growth since they rely upon the use of permanent plot markers.

Journal of Coastal Conservation↗

USGS2019

Deer do not affect short-term rates of vegetation recovery in overwash fans on Fire Island after Hurricane Sandy

1. Coastal resilience is threatened as storm-induced disturbances become more frequent and intense with anticipated changes in weather patterns. After severe storms, rapid recovery of vegetation, especially that of dune-stabilizing plants, is a fundamental property of coastal resilience. Herbivores may affect resilience by selectively foraging palatable plant species in disturbed areas. Knowledge of herbivore impacts to dune recovery after storm events is crucial to management of coastal properties. 2. We combined imagery classification, wildlife monitoring, and trend analysis to investigate effects of white-tailed deer on recovery rates of vegetation over four years post-storm in nine areas overwashed. We estimated local deer density with trail cameras, coupled deer density with primary productivity, and assessed the relationship between deer density and rates of vegetation recovery in overwash fans. 3. Pre-storm vegetation cover consisted of shrubs and sporadic patches of beachgrass. Post-storm cover was dominated by beachgrass. At current recovery rates, vegetation coverage will return to pre-storm conditions within the decade, though community transition from grasses to shrubs will take longer and will vary by site with the rate of dune formation. 4. The effect of deer on rates of vegetation recovery was negative, but not statistically significant nor biologically compelling. Although effects of trampling are evident in classified imagery, deer foraging on beachgrass had little effect on rates of spread throughout overwash fans. 5. Our research provides perhaps the first assessment of the effects of deer on post-storm vegetation recovery. While the rate of spread of the primary dune-building plant species was not deleteriously affected by deer, locally high deer densities will likely affect the establishment and development of more palatable herbs and shrubs.

New York↗

USGS2019

Effects of white-tailed deer (Odocoileus virginianus) exclusion on plant recovery in overwash fans after a severe coastal storm

We documented the impacts of a hyper-abundant deer population on dune vegetation recovering from severe storm surge on a barrier island through use of permanent plots and a repeated measures analysis. Three years after landfall of the storm, vegetation cover was dominated by American beachgrass, Ammophila breviligulata, though we observed twelve plant species among plots surveyed. We documented significantly greater vegetation cover in fenced than unfenced plots in overwash fans in two consecutive years. The difference in species richness between fenced and unfenced plots was significant, though richness was consistently low (≤4 species per plot) and we did not detect a statistically significant difference between years. Both deer trampling and foraging effects were captured in this study, though separation between these effects was not possible. Because trampling effects are often exacerbated on sandy soils, trampling and foraging effects should be isolated and investigated in future assessments of deer impacts on coastal vegetation. Managing deer to lower abundance may enhance coastal resilience if vegetation is allowed to recover unimpeded by foraging and trampling, though a better understanding of the precise nature of deer impacts on dune vegetation is necessary.

AoB PLANTS↗

USGS2019

White-tailed deer movements and space use on Fire Island: A four-year radio-telemetry study 2015-2016 post-Hurricane Sandy assessment

Hurricane Sandy provided a unique opportunity to better understand the movements of Fire Island’s dense white-tailed deer (Odocoileus virginianus borealis) herds. White-tailed deer inhabit all areas of Fire Island National Seashore and their high densities negatively affect native vegetation in several areas of the island, especially as disturbed areas attempt to recover after a catastrophic storm like Hurricane Sandy. Understanding deer movements and space use helps land managers to prioritize white-tailed deer population size and the health and recovery potential of Fire Island’s natural lands according to their management goals. The results of this study will inform Fire Island staff as they prepare to initiate the tasks set forth by the Seashore’s approved Deer Management Plan. We used radio-collars fitted with Very High Frequency (VHF) signal and Global Positioning System (GPS) technology to monitor movements of white-tailed deer for four years after Hurricane Sandy. The greatest movements of Fire Island’s adult female white-tailed deer occurred in spring each year. Home range and core area sizes varied among study areas and years, but suggested hierarchical dominance among Fire Island’s deer populations. Potentially six distinct populations were delineated through analysis of GPS radio-collar data, though these divisions also reflect the concentrated sampling efforts of deer capture. Nearly all deer monitored shared time between natural and nearby built environments. Since Hurricane Sandy, deer movements in Fire Island’s Wilderness are divided by the storm-induced breach. GPS radio-collars provided a wealth of data for analysis of deer movements and space use, and this report is simply a snapshot of the potential information we intend to gain from this study.

New York↗

USGS2018

Quantifying effects of deer browsing on vegetation establishment, growth and development in large-extent overwash fans

Hurricane Sandy provided a unique opportunity to better understand the potential effects of white-tailed deer ( Odocoileus virginianus borealis ) on recovering vegetation in areas overwashed by Hurricane Sandy in the Otis Pike Fire Island High Dune Wilderness Area. White-tailed deer are the dominant herbivore on Fire Island and they are known to decrease plant diversity, limit reproduction and growth of some plant species, and facilitate growth and expansion of non-native species through selective browsing. Deer also negatively affect the federally-threatened seabeach amaranth plants along the island’s beaches. Deer impacts to forest understory and regeneration have been documented in Fire Island’s Sunken Forest for decades, though their impacts to recovering dune vegetation are less understood and could restrict the resilience and recovery of primary dunes. Through use of several vegetation assessment methods, including point intercept and paired permanent exclosures, and deer monitoring with trail cameras, we documented high variability in among-overwash species richness, vegetation cover, and local deer abundance. We observed 29 vegetation species among overwash fans between 2015 and 2016. Greater vegetation cover was observed in northern (i.e., inland) areas of all overwash fans, and greater cover and species richness were documented in fenced permanent plots than in control plots. The greatest effect of deer browsing to recovering dune vegetation was in total vegetation cover, which was significantly greater in fenced permanent plots. Any amaranth plants left open (i.e., un-exclosed) were often heavily browsed and experienced early onset mortality without reproducing. Since Hurricane Sandy, total vegetation cover in overwash fans has significantly increased each year, despite deer activity and a regional drought in 2016. While deer graze and browse vegetation in overwash fans, deer and humans trample vegetation in some overwash fans and separating effects of each is not possible from exclusion studies alone. Two overwash fans have been consistently impacted by coastal disturbances since Hurricane Sandy, further complicating their recoveries. Monitoring of dune vegetation should continue as communities transition from predominantly grasses to shrubs and forbs to assess effects of deer as palatability of vegetation improves.

New York↗