Andrew Kleinhesselink

• PhD Ecology
• Rangeland Ecologist at University of Montana

Woody encroachment into grasslands and shrublands disrupts ecosystem processes and reduces biodiversity. Tree removal is a widespread strategy to restore ecosystem services and biodiversity in impacted landscapes. However, tree removal can also increase the risk of invasion by exotic annual grasses. In western North America, juniper (Juniperus spp....

Sagebrush ecosystems of western North America are experiencing widespread loss and degradation by invasive annual grasses. Positive feedbacks between fire and annual grasses are often invoked to explain the rapid pace of these changes, yet annual grasses also appear capable of achieving dominance among vegetation communities that have not burned fo...

The US Bureau of Land Management (BLM) manages nearly 1 million km² of public lands that support recreation, livestock production, and wildlife habitat. Monitoring the condition of vegetation on these lands is crucial for sound management but has historically been difficult to do at scale. Here we used newly developed remote-sensing tools to conduc...

Wildfires are a growing management concern in western US rangelands, where invasive annual grasses have altered fire regimes and contributed to an increased incidence of catastrophic large wildfires. Fire activity in arid, nonforested ecosystems is thought to be largely controlled by interannual variation in fuel amount, which in turn is controlled...

When species simultaneously compete with two or more species of competitor, higher‐order interactions (HOIs) can lead to emergent properties not present when species interact in isolated pairs. To extend ecological theory to multi‐competitor communities, ecologists must confront the challenges of measuring and interpreting HOIs in models of competi...

Turnover in species composition and the dominant functional strategies in plant communities across environmental gradients is a common pattern across biomes, and is often assumed to reflect shifts in trait optima. However, the extent to which community‐wide trait turnover patterns reflect changes in how plant traits affect the vital rates that ulti...

Aim In the western United States, sagebrush (Artemisia spp.) and salt desert shrublands are rapidly transitioning to communities dominated by exotic annual grasses, a novel and self‐reinforcing state that threatens the economic sustainability and conservation value of rangelands. Climate change is predicted to favour annual grasses, potentially pus...

Mitigating ecosystem service (ES) trade‐offs is a key management goal in locations where stakeholders value different and potentially conflicting ecosystem services (ESs). However, studies are not often designed to examine how local management actions address ES trade‐offs, and therefore do not provide options that can alleviate conflict. In semi‐a...

Wildfires are a growing management concern in western US rangelands, where invasive annual grasses have altered fire regimes and contributed to an increased incidence of catastrophic large wildfires. Fire activity in arid, non-forested ecosystems is thought to be largely controlled by interannual variation in fuel amount, which in turn is controlle...

Plant species can show considerable morphological and functional variation along environmental gradients. This intraspecific trait variation (ITV) can have important consequences for community assembly, biotic interactions, ecosystem functions and responses to global change. However, directly measuring ITV across many species and wide geographic ar...

Species identification can be challenging for biologists, healthcare practitioners and members of the general public. Snakes are no exception, and the potential medical consequences of venomous snake misidentification can be significant. Here, we collected data on identification of 100 snake species by building a week-long online citizen science ch...

Turnover in species composition and community-wide functional traits across environmental gradients is a ubiquitous pattern in ecology, and is generally assumed to reflect shifts in trait optima across these gradients. However, the demographic processes that give rise to these trait turnover patterns at the community level remain unclear. We asked...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Plain Language Summary Over the past 100 years, woody shrubs have increased in abundance in many semiarid grasslands around the world, replacing the grasses that are the most valuable forage for livestock. Ecologists have long sought to understand if overgrazing is responsible for shrub invasion and if shrub‐invaded areas can be restored back to gr...

When species simultaneously compete with two or more species of competitor, higher order interactions (HOIs) can lead to emergent properties not present when species interact in isolated pairs. In order to extend ecological theory to multi-competitor communities, ecologists must develop a practical and general definition for HOIs that can be applie...

Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Brom...

Understanding the role of native biodiversity in controlling exotic species invasion is a critical goal in ecology. In terrestrial plant communities, most research has focused on the effects of native vascular plants on invasion by exotic vascular plants. However, in many ecosystems, native bryophytes and other non‐vascular plants are common and ca...

Leaf traits are frequently measured in ecology to provide a ‘common currency’ for predicting how anthropogenic pressures impact ecosystem function. Here, we test whether leaf traits consistently respond to experimental treatments across 27 globally distributed grassland sites across 4 continents. We find that specific leaf area (leaf area per unit...

Understanding how annual climate variation affects population growth rates across a species' range may help us anticipate the effects of climate change on species distribution and abundance. We predict that populations in warmer or wetter parts of a species' range should respond negatively to periods of above average temperature or precipitation, r...

Stable coexistence requires intraspecific limitations to be stronger than interspecific limitations. The greater the difference between intra‐ and interspecific limitations, the more stable the coexistence, and the weaker the competitive release any species should experience following removal of competitors. We conducted a removal experiment to tes...

Background Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes...

Additional details on the statistical model

Background Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes...

A number of modeling approaches have been developed to predict the impacts of climate change on species distributions, performance and abundance. The stronger the agreement from models that represent different processes and are based on distinct and independent sources of information, the greater the confidence we can have in their predictions. Eva...

Delivered at the Restoring the West Conference in Logan UT. https://digitalcommons.usu.edu/rtw/2016/Oct19/6/ Sagebrush ecosystems cover vast areas of the West and are home to many species of conservation concern. Unfortunately, distribution models predict that the total area suitable for sagebrush could be greatly reduced over the next 100 years...

Plant population models are powerful tools for predicting climate change impacts in on location but are difficult to apply at landscape scales. We overcome this limitation by taking advantag of two recent advances: remotely sensed, species-specifi estimates of plant cover and statistical model develope for spatiotemporal dynamics of animal populati...

Theory predicts that strong indirect effects of environmental change will impact communities when niche differences between competitors are small and variation in the direct effects experienced by competitors is large, but empirical tests are lacking. Here we estimate negative frequency dependence, a proxy for niche differences, and quantify the di...

Understanding how climate change will affect the abundance of dominant plants is a critical question for conservation in the 21st century. We used long-term field observations of sagebrush (Artemisia tridentata) cover and production to estimate sagebrush sensitivity to annual precipitation and temperature across its range. Our analysis draws from 1...

Anthropogenic environmental change can affect species directly by altering physiological rates or indirectly by changing competitive outcomes. The unknown strength of competition-mediated indirect effects makes it difficult to predict species abundances in the face of ongoing environmental change. Theory developed with phenomenological competition...

Background/Question/Methods Forecasting the impacts of climate change on plant communities over large spatial extents requires understanding population dynamics at similar extents. However, virtually all studies of plant population dynamics rely on demographic observations at the meter to sub-meter scale, and extrapolating small-scale studies to...

Background/Question/Methods Environmental change can affect species indirectly by changing the abundances of competitors and the intensity of competition. The unknown strength of competition-mediated indirect effects complicates attempts to predict the outcome of environmental changes such as global warming or N-deposition. Theory developed using...

Ecosystem-engineering plants modify the physical environment and can increase species diversity and exotic species invasion. At the individual level, the effects of ecosystem engineers on other plants often become more positive in stressful environments. In this study, we investigated whether the community-level effects of ecosystem engineers also...

Recent functional trait studies have shown that trait differences may favour certain species (environmental filtering) while simultaneously preventing competitive exclusion (niche partitioning). However, phenomenological trait-dispersion analyses do not identify the mechanisms that generate niche partitioning, preventing trait-based prediction of f...

The spread of exotic, invasive species is a global phenomenon that is recognized as a major source of environmental change. Although many studies have addressed the effects of exotic plants on the communities they invade, few have quantified the effects of invader removal on plant communities, or considered the degree to which different plant group...

Background/Question/Methods Many studies have found that facilitation between plants increases with environmental stress, in support of the stress-gradient hypothesis (SGH). While it has been hypothesized that increased facilitation at the individual level will have important consequences for the diversity, abundance and invasion of plant communi...

Background/Question/Methods Although the spread of invasive, exotic species is a global phenomenon recognized as a critical source of environmental change, few studies have quantified the impact of invasive plants on the communities they invade or considered the degree to which plant groups with different life histories, life forms and geographic...