Treesearch

Biogenic carbonates, including bivalve shells, record past environmental conditions, but their interpretation requires understanding environmental and biological factors that affect trace metal uptake. We examined stable barium (δ138Ba) and radiogenic strontium (87Sr/86Sr) isotope ratios in the aragonite shells of four native freshwater mussel species and two invasive species in five streams and assessed the effects of species identity, growth rate, and river water chemistry on shell isotopic composition. Shells were robust proxies for Sr, accurately reflecting 87Sr/86Sr ratios of river...

Understanding the relationship between multi-scale processes driving community and population-level diversity can guide conservation efforts. While the importance of population-level genetic diversity is widely recognized, it is not always assessed for conservation planning, and positive correlations with community-level diversity are sometimes assumed, such that only the latter is measured. We surveyed species richness and cumulative multispecies abundance of crayfishes in impounded and unimpounded streams in the southern Appalachian Mountains(Alabama,USA). We simultaneously assessed...

Bark beetles (Coleoptera: Curculionidae, Scolytinae) cause extensive tree mortality in conifer forests in the western United States. One method to protect conifers from bark beetles involves applications of liquid formulations of insecticides to the tree bole using high-pressure (e.g., ≥2,241 kPa) ground-based sprayers. Several active ingredients and products are effective when properly applied in accordance with the label. Researchers recently have developed more portable methods that inject small quantities of systemic insecticides directly into trees. The purpose of this review is to...

The restoration of global forests is urgently needed to offset climate change, biodiversity loss, and the emergence of viral pandemics (Anderegg et al. 2020; Everard et al. 2020; IPBES 2018). Deforestation continues unabated (Cruz et al. 2020; Reid et al. 2017), and the projected effects of a warmer, drier climate (Allen et al. 2010; Fagan et al. 2020) will increase the area of forests lost or degraded (Stanturf 2020). Calls continue for massive tree planting programs (Mader 2019; Trees that Count 2020), often without regard for ecological, historical, social, or economic context (Fagan et...

The landscape theory of food web architecture (LTFWA) describes relationships among body size, trophic position, mobility, and energy channels that serve to couple heterogenous habitats, which in turn promotes long-term system stability. However, empirical tests of the LTFWA are rare and support differs among terrestrial, freshwater, and marine systems. Further, it is unclear whether the theory applies in highly altered ecosystems dominated by introduced species such as the Laurentian Great Lakes. Here, we provide an empirical test of the LTFWA by relating body size, trophic position, and...

Addition of nitrogen (N) to forest soil may alter wood decay rates and fungal community structure and richness. In a northern Sweden Pinus sylvestris L. forest, two levels of ammonium nitrate were applied annually from 1971 to 2008. In 2007 we initiated an investigation into wood decay (assessed through mass loss) and fungal responses using stakes of trembling aspen (Populus tremuloides Michx.) and loblolly pine (Pinus taeda L.) wood installed at different soil depths in plots where zero (N0), low (34 kg; N1), or high (68 kg; N2) levels of N were applied. Stakes were located either...

Mercury is a persistent environmental pollutant emitted from fossil fuel combustion. It is widely dispersed in the environment and can be especially concentrated in peatlands. Peatlands provide many ecosystem services, such as carbon storage, water filtration, and wildlife habitat. However, environmental conditions in peatlands can be conducive to the formation of the highly toxic methylmercury that bioaccumulates in the aquatic food chain and leads to harmful health effects in humans, animals, and other fauna. The mercury methylation process occurs in conditions that are low in oxygen,...

Balsam woolly adelgid (BWA), Adelges piceae, is an invasive insect colonizing true fir in North America. Following its recent range expansion into Utah, BWA has caused significant mortality of subalpine fir (Abies lasiocarpa). The first instar (crawler) is the only motile life stage and is responsible for dispersal among trees, usually by wind. Due to BWA’s small size, detection and monitoring is challenging. In this study, monitoring for dispersing crawlers using sticky cards was compared to a more labor-intensive bark sampling method in four northern Utah stands with the goal of identifyi...