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Eduardo Gonzalez

Publications and source records attributed to Eduardo Gonzalez.

7 recordsLinked to original sources
USGS2022

Vegetation monitoring

Sonoran Institute, Pronatura Noroeste, and University of Arizona conducted vegetation monitoring in riparian restoration sites and control sites along the Colorado River corridor in Mexico during the fall (end of the growing season) of 2018. The overall goal of the vegetation monitoring program was to quantify impacts of restoration actions on the extent, composition, and structure of riparian habitat and to relate habitat characteristics to bird abundance and diversity. Specific monitoring objectives were to measure the vegetation vertical structure, density, and cover by species in active riparian restoration sites that had been planted prior to 2017 (> 2 years of growth) in Laguna Grande (CILA, Herradura, and Cori sites) and Miguel Alemán (Fig. 3-1) and to compare vegetation metrics in the restoration sites to the control sites to assess impacts of restoration. The Chaussé restoration site is scheduled for initial monitoring in 2021. This report chapter summarizes 2018 results from the restoration and control sites and compares restoration site results between 2017 and 2018.

Arizona, Baja California↗
USGS2021

Monitoring the results of stream corridor restoration

Often overlooked and underfunded, ecological monitoring is an essential component of stream-restoration work. It helps practitioners to identify successful restoration practices, detect ineffective ones, and adjust their adaptive-management activities to improve efficacy (Bernhardt and Palmer 2011). Monitoring, along with research and modeling, are the three legs of the scientific stool that support ecosystem restoration and management. Monitoring tells us what is happening, research tells us why and how it is happening, and modeling provides insights about what can happen under different management alternatives.

Book chapter↗
USGS2020

Ecological interfaces between land and flowing water: Themes and trends in riparian research and management

This paper provides an overview of past, present and future themes for research and management of riparian zones, often relating to papers within this Wetlands Special Feature. Riparian research expanded in the United States around 1980 with themes that recognized (1) damage from excessive livestock, or (2) damage from river damming and diversion, and (3) the beneficial capacity of riparian buffers to intercept and assimilate nutrients and other water contaminants. Research expanded globally in the 1990s, with themes including (4) plant life history requirements and (5) reliance on fluvial geomorphic dynamics that enable riparian rejuvenation. Resource managers recognized that riparian areas provide (6) rich wildlife habitats (7) along with valued ecosystem services, (8) which encouraged conservation and restoration initiatives, (9) including environmental flow regimes. Floodplains are (10) vulnerable to invasive plants and management has included biocontrol such as for Tamarix in the American Southwest. Into the twenty-first century, (11) climate change is advancing, and riparian ecosystems may be especially impacted due to the compound challenges from increasing water demand and declining summer flows. As an emerging opportunity, (12) while reservoirs submerge floodplain vegetation, reservoir deltas may support compensatory riparian wetlands. (13) Studies increasingly utilize remote sensing tools including satellite imagery, LiDAR and unmanned aircraft systems, and (14) the coordination of large data sets invites digital ecology, including artificial intelligence and machine learning. Since riparian zones are centres for human activities, (15) there are opportunities for citizen science, social media and internet applications, which will increasingly democratize riparian research and management.

Wetlands↗
USGS2020

Riparian plant communities remain stable in response to a second cycle of Tamarix biocontrol defoliation

Reduced abundance of non-native Tamarix shrubs in western U.S. riparian systems following biological control by a defoliating beetle has led to concerns that replacement plant communities could be dominated by other invasive species and/or not provide some of the ecosystem services that Tamarix was providing. In previous studies, Tamarix decline following biocontrol was accompanied by small increases in native and non-native herbaceous species, with variable responses of woody vegetation. However, none of these studies spanned periods longer than a decade since beetle release. This is an important caveat, given the cyclical nature of plant-herbivore interactions and potential lags in vegetation recovery. We report plant community response to an eight-year-long second cycle of Tamarix defoliation-refoliation in two reaches of the upper Colorado River in eastern Utah, 11–13 years after beetle arrival. Tamarix cover across sites initially declined an average of ca. 50% in response to the beetle, but then recovered. Changes in the associated plant community were small but supported common management goals, including a 47% average increase in cover of a native shrub ( Salix exigua ), and no secondary invasions by other non-native plants. We suggest that the effectiveness of biocontrol programs must be assessed case-by-case, and on a long-term basis.

Utah↗
USGS2020

Combined effects of biological control of an invasive shrub and fluvial processes on riparian vegetation dynamics

Plant community responses to biocontrol of invasive plants are understudied, despite the strong influence of the composition of replacement vegetation on ecosystem functions and services. We studied the vegetation response to a folivore beetle ( Diorhabda genus, Coleoptera) that has been introduced along southwestern US river valleys to control the invasion of non-native shrubs in the genus Tamarix (Tamaricaceae). We collected detailed plant compositional and environmental data during four different surveys over 7 years (2010–2017), including two surveys prior to when substantial beetle-induced dieback occurred in summer 2012, along the lower Virgin River, Nevada. The study river was of special interest because it is one of only a few largely unregulated rivers in the region, and a large flood of 40-year return period occurred between the first and second surveys, allowing us to study the combined effects of fluvial processes, which typically drive riparian plant community assembly, and biocontrol. Vegetation trajectories differed as a function of the dominant geomorphological process. Tamarix cover declined an average of 75% and was replaced by the native shrub Pluchea sericea as the new dominant species in the floodplain, especially where sediment deposition predominated. Following deposition, and especially erosion, opportunistic native herbs, Tamarix seedlings, and noxious weeds colonized the understory layer but did not increase in cover over time. Stands of the native shrub Salix exigua , a desirable replacement species following Tamarix control, only increased slightly and remained subordinate in the floodplain. Overall, our results showed that, by successfully controlling the target non-native plant, a biocontrol agent can substantially modify the replacement plant communities in a riparian system, but that fluvial processes also strongly influence the resulting communities.

Arizona, Nevada, Utah↗
USGS2018

Regeneration of Salicaceae riparian forests in the Northern Hemisphere: A new framework and management tool

Human activities on floodplains have severely disrupted the regeneration of foundation riparian shrub and tree species of the Salicaceae family ( Populus and Salix spp.) throughout the Northern Hemisphere. Restoration ecologists initially tackled this problem from a terrestrial perspective that emphasized planting. More recently, floodplain restoration activities have embraced an aquatic perspective, inspired by the expanding practice of managing river flows to improve river health (environmental flows) . However, riparian Salicaceae species occupy floodplain and riparian areas, which lie at the interface of both terrestrial and aquatic ecosystems along watercourses . Thus, their regeneration depends on a complex interaction of hydrologic and geomorphic processes that have shaped key life-cycle requirements for seedling establishment . Ultimately, restoration needs to integrate these concepts to succeed. However, while regeneration of Salicaceae is now reasonably well-understood, the literature reporting restoration actions on Salicaceae regeneration is sparse, and a specific theoretical framework is still missing. Here, we have reviewed 105 peer-reviewed published experiences in restoration of Salicaceae forests, including 91 projects in 10 world regions, to construct a decision tree to inform restoration planning through explicit links between the well-studied biophysical requirements of Salicaceae regeneration and 17 specific restoration actions, the most popular being planting (in 55% of the projects), land contouring (30%), removal of competing vegetation (30%), site selection (26%), and irrigation (24%). We also identified research gaps related to Salicaceae forest restoration and discuss alternative, innovative and feasible approaches that incorporate the human component.

Journal of Environmental Management↗