Skip to main content

Helen Sofaer

Helen Sofaer is a Research Ecologist at the Pacific Island Ecosystems Research Center in Hawaii.

Science and Products

Filter Total Items: 16

Negative effects of an allelopathic invader on AM fungal plant species drive community‐level responses

The mechanisms causing invasive species impact are rarely empirically tested, limiting our ability to understand and predict subsequent changes in invaded plant communities. Invader disruption of native mutualistic interactions is a mechanism expected to have negative effects on native plant species. Specifically, disruption of native plant‐fungal mutualisms may provide non‐mycorrhizal plant invad
By
Ecosystems, Fort Collins Science Center

Ecological forecasting—21st century science for 21st century management

Natural resource managers are coping with rapid changes in both environmental conditions and ecosystems. Enabled by recent advances in data collection and assimilation, short-term ecological forecasting may be a powerful tool to help resource managers anticipate impending near-term changes in ecosystem conditions or dynamics. Managers may use the information in forecasts to minimize the adverse ef
By
Ecosystems, Water Resources, Science Analytics and Synthesis (SAS), Wildlife Program, Eastern Ecological Science Center, Pacific Island Ecosystems Research Center, Fort Collins Science Center, Kansas Water Science Center, Maryland-Delaware-D.C. Water Science Center, National Wildlife Health Center, New Jersey Water Science Center, Patuxent Wildlife Research Center, Southwest Biological Science Center, Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center

A modeling workflow that balances automation and human intervention to inform invasive plant management decisions at multiple spatial scales

Predictions of habitat suitability for invasive plant species can guide risk assessments at regional and national scales and inform early detection and rapid-response strategies at local scales. We present a general approach to invasive species modeling and mapping that meets objectives at multiple scales. Our methodology is designed to balance trade-offs between developing highly customized model
By
Ecosystems, Fort Collins Science Center

Co-occurrence and occupancy dynamics of mourning doves and Eurasian collared-doves

Understanding how land cover and potential competition with invasive species shape patterns of occupancy, extirpation, and colonization of native species across a landscape can help target management for declining native populations. Mourning dove (Zenaida macroura) populations have declined throughout the United States from 1965–2015. The expansion of the Eurasian collared‐dove (Streptopelia deca
By
Ecosystems, Fort Collins Science Center

The development and delivery of species distribution models to inform decision-making

Information on where species occur is central to conservation and management decisions, but knowledge of distributions can be coarse or incomplete. Species distribution models provide a tool for mapping suitable habitat, and can produce credible, defensible, and repeatable predictive information with which to inform decisions. However, these models are sensitive to data inputs and methodological c
By
Ecosystems, Fort Collins Science Center

Non-native plants have greater impacts because of differing per-capita effects and non-linear abundance-impact curves

Invasive, non-native species can have tremendous impacts on biotic communities, where they reduce the abundance and diversity of local species. However, it remains unclear whether impacts of non-native species arise from their high abundance or whether each non-native individual has a disproportionate impact – i.e., a higher per-capita effect – on co-occurring species compared to impacts by native
By
Ecosystems, Fort Collins Science Center

Clustering and ensembling approaches to support surrogate-based species management

AimSurrogate species can provide an efficient mechanism for biodiversity conservation if they encompass the needs or indicate the status of a broader set of species. When species that are the focus of ongoing management efforts act as effective surrogates for other species, these incidental surrogacy benefits lead to additional efficiency. Assessing surrogate relationships often relies on grouping
By
Ecosystems, Fort Collins Science Center

The area under the precision‐recall curve as a performance metric for rare binary events

Species distribution models are used to study biogeographic patterns and guide decision‐making. The variable quality of these models makes it critical to assess whether a model's outputs are suitable for the intended use, but commonly used evaluation approaches are inappropriate for many ecological contexts. In particular, unrealistically high performance assessments have been associated with mode
By
Ecosystems, Fort Collins Science Center

Integrating landscape simulation models with economic and decision tools for invasive species control

In managing invasive species, land managers and policy makers need information to help allocate scarce resources as efficiently and effectively as possible. Decisions regarding treatment methods, locations, effort, and timing can be informed by the integration of landscape simulation models with economic tools. State and transition simulation models align with conceptual models of ecosystem change
By
Ecosystems, Fort Collins Science Center

The relationship between invader abundance and impact

The impacts of invasive species generally increase with their abundance, but the form of invader abundance–impact relationships remain poorly described. We highlight the utility of abundance–impact curves for three questions. First, abundance–impact relationships can clarify whether prevention and management should focus on the species likely to become abundant or those likely to cause large impac
By
Ecosystems, Fort Collins Science Center

Misleading prioritizations from modelling range shifts under climate change

AimConservation planning requires the prioritization of a subset of taxa and geographical locations to focus monitoring and management efforts. Integration of the threats and opportunities posed by climate change often relies on predictions from species distribution models, particularly for assessments of vulnerability or invasion risk for multiple taxa. We evaluated whether species distribution m
By
Ecosystems, Fort Collins Science Center

Projecting species’ vulnerability to climate change: Which uncertainty sources matter most and extrapolate best?

Species distribution models (SDMs) are commonly used to assess potential climate change impacts on biodiversity, but several critical methodological decisions are often made arbitrarily. We compare variability arising from these decisions to the uncertainty in future climate change itself. We also test whether certain choices offer improved skill for extrapolating to a changed climate and whether
By
Ecosystems, Fort Collins Science Center
link
Aerial photo of the prairie pothole region of North American

Webinar: Projecting Climate Change Impacts on Wetland-Dependent Birds in the Prairie Pothole Region

View this webinar to learn how scientists are projecting the impacts of climate change on birds in the Prairie Pothole Region.
By
Northeast Climate Science Center, Climate Adaptation Science Center
link

Webinar: Projecting Climate Change Impacts on Wetland-Dependent Birds in the Prairie Pothole Region

View this webinar to learn how scientists are projecting the impacts of climate change on birds in the Prairie Pothole Region.
Learn More
link
delta waters with a significant amount of floating vegetation

The Role of Climate in Shaping Invasive Plant Abundance across Different Spatial Locations

Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. T
By
Climate Adaptation Science Centers, Climate Adaptation Science Center
link

The Role of Climate in Shaping Invasive Plant Abundance across Different Spatial Locations

Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. T
Learn More
link
delta waters with a significant amount of floating vegetation

The Role of Climate in Shaping Invasive Plant Abundance across Different Spatial Locations

Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. T
By
Climate Adaptation Science Centers, Climate Adaptation Science Center
link

The Role of Climate in Shaping Invasive Plant Abundance across Different Spatial Locations

Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. T
Learn More
link
The RAM room VisWall display using 24 individual monitor outputs

Documenting, Mapping, and Predicting Invasive Species Using the Fort Collins Science Center's RAM (Resource for Advanced Modeling)

The Resource for Advanced Modeling room provides a collaborative working environment for up to 20 scientists, supported with networked, wireless computing capability for running and testing various scientific models (e.g., Maxent, Boosted Regression Trees, Logistic Regression, MARS, Random Forest) at a variety of spatial scales, from county to global levels. Models use various predictor layers...
By
Invasive Species Program, Fort Collins Science Center
link

Documenting, Mapping, and Predicting Invasive Species Using the Fort Collins Science Center's RAM (Resource for Advanced Modeling)

The Resource for Advanced Modeling room provides a collaborative working environment for up to 20 scientists, supported with networked, wireless computing capability for running and testing various scientific models (e.g., Maxent, Boosted Regression Trees, Logistic Regression, MARS, Random Forest) at a variety of spatial scales, from county to global levels. Models use various predictor layers...
Learn More

Co-occurrence and Occupancy Dynamics of Mourning Doves and Eurasian Collared-Doves

Data on mourning dove and Eurasian collared-dove occurrences, and associated covariates.
By
Fort Collins Science Center

Data on the impacts of garlic mustard from a weeding experiment in Pennsylvania 2006-2016

Data were collected on the abundance of plants in a 10-year weeding experiment of garlic mustard, located at Trillium Trails Park in Pennsylvania. Garlic mustard was weeded annually to suppress its abundance, and the impacts of garlic mustard were measured based on the response of the plant community to garlic mustard weeding. Because garlic mustard is known to suppress mycorrhizal fungi, the myco
By
Fort Collins Science Center

Non-native and synanthropic bird data derived from 2010-2012 Breeding Bird Survey and associated landscape metrics from 2011 NLCD

Locations of and proportional abundance of non-native and synanthropic passerines were extracted from Breeding Bird Survey (BBS) data from 2010-2012. Information characterizing the spatial variation and the associated amount, aggregation, and diversity of developed and agricultural land cover types was extracted from the National Land Cover Datasets of 2011. Data supported analyses in the publicat
By
Fort Collins Science Center

Abundance of wetland-dependent birds at Breeding Bird Survey routes and associated land cover and climate information

Estimation and validation data for site by species matrices used in the publication 'Clustering and ensembling approaches to support surrogate-based species management' by H.R. Sofaer et al. 2019 Diversity and Distributions
By
Fort Collins Science Center

Measurements of plant abundance with reference to dominant plants in Illinois wetlands

Data were collected on plant abundance in Illinois with the goal of determining correlations between the abundance of dominant plant taxa and other plant species.
By
Fort Collins Science Center

Breeding Bird Survey songbird occurrences during 1977-1979 and 2012-2014 in conterminous U.S.

Data used in: "Misleading prioritizations from modeling range shifts under climate change" by H.R. Sofaer, C.S. Jarnevich, and C.H. Flather. Breeding Bird Survey data (version 2014.0) for songbirds were summarized over historical (1977-1979) and recent (2012-2014) time periods at routes in the conterminous U.S. Avian occurrence data were combined with information on climate and land cove
By
Fort Collins Science Center

Data associated with Sofaer and Jarnevich 'Accounting for sampling patterns reverses the relative importance of trade and climate for the global sharing of exotic plants'

These data were analyzed for the publication 'Accounting for sampling patterns reverses the relative importance of trade and climate for the global sharing of exotic plants': Aim: Exotic species distributions reflect patterns of human-mediated dispersal, species climatic tolerances, and a suite of other biotic and abiotic factors. The relative importance of each of these factors will shape how the
By
Fort Collins Science Center

Data used to estimate and project the effects of climate and land use change on wetland densities in the Prairie Pothole Region

These data were used to estimate models relating climate and land cover to wetland densities and develop projections under climate and land use change. Data for model estimation were derived from historical climate data, estimates of hydrological processes based on the Variable Infiltration Capacity model, National Wetlands Inventory, and the National Land Cover Database. Wetland densities were ba
By
Climate Adaptation Science Centers, Climate Adaptation Science Center

climatchR: An implementation of Climatch in R

Matching climate envelopes of allows people to examine how potential invasive species may match habitats. The Australian government created Climatch to do allow for these comparisons. However, this webpage does not allow for readily scripting climate matching. Hence, the authors created climatchR, an R package (R Core Team 2020) implementing the climatch method in R. This was created to allow auto
By
Upper Midwest Environmental Sciences Center

Science and Products