Treesearch

Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian insects using light traps at dusk from April through October 2017–2020. River runners collected these data on 1,428 events over 611 sampling nights at 410 sites throughout a 470-km segment of the Colorado...

White-tailed deer (Odocoileus virginianus) have been overabundant in eastern North America for more than five decades, resulting in depauperate understories and ricocheting effects on higher trophic levels. Even after deer populations are reduced, understory plant communities may fail to recover for an unknown length of time due to persistent legacy effects.We surveyed understory plant communities in six deer exclosures and paired reference plots in northwestern Pennsylvania to determine the degree to which 19 years of deer exclusion was sufficient for recovery of species richness,...

Climate change represents an existential threat to many forest ecosystems because tree populations are often adapted to local climate means and variability. If tree populations cannot migrate or adapt, they risk becoming increasingly maladapted with climate change. This emerging mismatch underscores the need for climate adaptive management techniques, such as assisted migration of tree species, to help mitigate climate change impacts on forest ecosystems. Although biotic and abiotic factors are known to constrain tree establishment success, the extent to which they may determine the...

Managing forests for biodiversity conservation while maintaining economic output is a major challenge globally and requires accurate and timely monitoring of imperiled species. In the Pacific Northwest, USA, forest management is heavily influenced by the status of northern spotted owls (Strix occidentalis caurina), which have been in continued population decline for the past four decades. The monitoring program for northern spotted owls is transitioning from mark–resight surveys to a passive acoustic framework, requiring development of alternative analysis approaches. To maintain relevance...

Considerable confusion has occurred regarding the taxonomy of Gilpinia hercyniae (Adams and Entwistle 1981). Hartig first described Lophyrus polytomus in 1834, and then Lophyrus hercyniae in 1837 as two distinct spruce-feeding sawfly species in Europe. In 1910, both species were moved to the genus Diprion, but many authors continued to use Lophyrus. In 1912, a different author synonymized L. hercyniae under L. polytomus. Then in 1939, Benson erected a new genus, Gilpinia, under which he listed L. polytomus as G. polytoma, but did not recognize L. hercyniae. Soon thereafter, Reeks (1941)...

Natural disturbances can maintain forest diversity by creating a heterogeneous resource landscape, which can contribute to coexistence of early- and late-successional species. However, almost all forested ecosystems are also subject to multiple anthropogenic stressors, which could inhibit plant diversity and forest recovery after natural disturbances. Here, we present the first large-scale replicated field experiment testing the interactions among two natural and two anthropogenic disturbances in a mature secondary temperate forest. Specifically, we test the extent to which: 1. a natural...

This report describes status and trends in watershed condition across the Northwest Forest Plan (NWFP) area over the first 25 years since its inception in 1994. The program charged with this task is the Aquatic and Riparian Effectiveness Monitoring Program (AREMP), which has assembled information from field data collection, spatial datasets, and a host of landscape models to evaluate the status and trends in aquatic resources in streams and watersheds. Field data included hydrologic measurements (stream wetted widths and temperatures), geomorphic responses (instream wood and sediment), and...

The movement of species around the world has greatly increased with rising trade and commerce from globalization (Hulme, 2009; Pyšek et al., 2010) and rapidly changing environments due to climate change (Bebber et al., 2013; Walther et al., 2009). In new areas, species may experience different ecological processes from those that regulate their populations in their native geographic range and/or they may encounter an environment that is particularly sensitive to their presence (Colautti et al., 2004; Jeschke et al., 2012). Consequently, species can become disruptive to novel landscapes....

The Palearctic ground beetle Carabus granulatus Linneaus, 1758 has been accidentally introduced to North America on multiple occasions. We review previous reports of its North American colonization history, and document range expansion into northern California, Montana, New York state, Vermont, and Maine. We also review its several reported interceptions. The species is eurytopic, occupying marginal heathland and open wet forest habitats in the Old World, and is not particularly associated with human habitation. New World populations retain these habitat preferences, with established...