Elizabeth B. Harper

• Ph.D.
• Executive Director at Lake Sunapee Protective Association

Populations of species with complex life cycles have the potential to be regulated at multiple life history stages. However, research tends to focus on single stage density-dependence, which can lead to inaccurate conclusions about population regulation and subsequently hinder conservation efforts. In amphibians, many studies have demonstrated stro...

Much of the biodiversity associated with isolated wetlands requires aquatic and terrestrial habitat to maintain viable populations. Current federal wetland regulations in the United States do not protect isolated wetlands or extend protection to surrounding terrestrial habitat. Consequently, some land managers, city planners, and policy makers at t...

Mechanism-based ecological models are a valuable tool for understanding the drivers of complex ecological systems and for making informed resource-management decisions. However, inaccurate conclusions can be drawn from models with a large degree of uncertainty around multiple parameter estimates if uncertainty is ignored. This is especially true in...

At last, a book that will allow you to identify most of the amphibians found in the world famous biodiversity hotspots of the Eastern Arc Mountains and Coastal Forests of Tanzania and Kenya. This guide allows both the English and the Swahili reader to identify and obtain natural history and conservation information for the 122 species of amphibians...

Recently metamorphosed amphibians transport substantial biomass and nutrients from wetlands to terrestrial ecosystems. Previous estimates (except 1) were limited to either a subset of the community or a single year. Our goal was to examine temporal variability in biomass export of all amphibians within breeding ponds and the composition of that exp...

Forestry practices affect various habitat characteristics that influence wildlife populations. Understanding the relative importance of the broad effects of forestry practices versus specific habitat variables for wildlife may help managers balance multiple forest management objectives and potentially adjust forestry practices to better conserve bi...

Ecosystem service-support tools are commonly used to guide natural resource management. Often, empirically based models are preferred due to low data requirements, simplicity and clarity. Yet, uncertainty produced by local context or parameter estimation remains poorly quantified and documented. We assessed model uncertainty of the Revised Universa...

To investigate effects of timber harvest on small mammals, we compared capture rates in experimental forestry arrays of uncut forest, partial cut forest, and clearcuts with high and low coarse downed wood in Missouri, USA. Past studies show that effects of timber harvest on small mammals depend on species and forest type. We used an information the...

We examined pond-breeding amphibian community composition at 210 ponds in Missouri between 2002 and 2012 using drift fence, dipnet, and funnel trap data. We encountered a total of 20 pond-breeding amphibian species in the combined surveys. We also examined whether the presence of American Bullfrogs, Lithobates catesbeianus, and fish influenced thes...

Forest loss is a primary cause of worldwide amphibian decline. Timber harvesting in the United States has caused dramatic changes in quality and extent of forest ecosystems, and intensive forest management still occurs. Although numerous studies have documented substantial reductions in amphibian densities related to timber harvest, subsequent exti...

Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in bre...

Predation represents an important driver of species persistence and community structure. Climate change can influence predation through changes in the distribution and abundance of predatory species. Furthermore, predator-prey dynamics may be influenced by climate-induced shifts in the behavior of predators and/or prey. Our research employed a mode...

Aim We map estimated historical population declines resulting from species‐specific models of sensitivity to habitat fragmentation for three forest‐dependent chameleons. Location East Usambara Mountains, Eastern Arc Mountains, Tanzania. Methods We surveyed three chameleon species ( Rhampholeon spinosus , Rhampholeon temporalis and Trioceros derem...

Successful forest management for multiple uses requires balancing extractive practices with maintaining biodiversity, among other important goals. Amphibians comprise an important and abundant part of the biodiversity of many forests. Previous studies have documented declines in the abundance and diversity of amphibians in harvested forests. Howeve...

Background/Question/Methods Habitat modification in the form of fragmentation and loss is a leading cause of biodiversity decline. The basic predictions from island biogeography theory that species richness and population size decrease with declining area and increased isolation have received considerable support. However much of this research ha...

Harvesting of chameleons from the East Usambara Mountains of Tanzania for the exotic pet trade is of concern due to the high rates of habitat loss in this region and the fact that many of the species are endemic or near endemic to this isolated montane forest. Export of the majority of chameleons found in the East Usambaras is regulated by their li...

Appropriate application of complex models to estimate system behavior requires understanding the influence of model structure and parameter estimates on model output. To date, most researchers perform local sensitivity analyses, rather than global, because of computational time and quantity of data produced. Local sensitivity analyses are limited i...

Background/Question/Methods Ecological models offer a valuable tool for understanding complex ecological systems. However, inaccurate conclusions can be drawn from models with a large degree of uncertainty around multiple parameter estimates if uncertainty is ignored. We addressed this issue for a mechanism-based model of Populus fremontii (Fremo...

Fremont cottonwood (Populus fremontii) is an important component of semi-arid riparian ecosystems throughout western North America, but its populations are in decline due to flow regulation. Achieving a balance between human resource needs and riparian ecosystem function requires a mechanistic understanding of the multiple geomorphic and biological...

In high-order alluvial river systems, physical factors of flooding and channel migration are particularly important drivers of riparian forest dynamics because they regulate habitat creation, resource fluxes of water, nutrients and light that are critical for growth, and mortality from fluvial disturbance. Predicting vegetation composition and dyna...

Harvesting timber is a common form of land use that has the potential to cause declines in amphibian populations. It is essential to understand the behavior and fate of individuals and the resulting consequences for vital rates (birth, death, immigration, emigration) under different forest management conditions. We report on experimental studies co...

Background/Question/Methods Sensitivity analyses can determine how robust model outcomes are to uncertainty in parameter estimates. The most basic sensitivity analyses hold all but one parameter in a model constant while quantifying the effects of altering a single parameter. However, if there is uncertainty in other model parameters then it is un...

Background/Question/Methods River floodplains are dynamic environments where strong physical and abiotic forces interact. In large, alluvial river systems, periodic flooding drives channel meandering and cutoff events, which set the physical template for the establishment of biotic communities. As a result, the riparian ecosystem in these settings...

Knowing the phenologies of species in a region helps guide management and conservation activities in breeding ponds and surrounding terrestrial habitats. We examined the phenology of pond-breeding amphibians in central Missouri oak-hickory forests. Two ponds were monitored for 4 y from 2000–2003 and five other ponds were monitored for 1 y during 20...

Juvenile survival is an important life history feature, because recent modeling efforts suggest that modest changes in juvenile survival rates due to habitat change may greatly affect population growth rates. We compared water loss and survival rates of recently metamorphosed American Toad (Anaxyrus americanus), Green Frog (Lithobates clamitans), a...

To predict the effects of terrestrial habitat change on amphibian populations, we need to know how amphibians respond to habitat heterogeneity, and whether habitat choice remains consistent throughout the life-history cycle. We conducted four experiments to evaluate how the spatial distribution of juvenile wood frogs, Rana sylvatica (including both...

Numerous studies have documented the decline of amphibians following timber harvest. However, direct evidence concerning the mechanisms of population decline is lacking and hinders attempts to develop conservation or recovery plans and solutions for forest species. We summarized the mechanisms by which abundance of amphibians may initially decline...

I used both demographic modeling and experimental field research to evaluate the role of terrestrial habitat in the population dynamics and conservation of pond-breeding amphibians. I began by using literature data to develop stochastic, stage-structured demographic models for two pond-breeding amphibian species and used these models to determine t...