Airborne environmental DNA (eDNA) research has typically focused on the detection of pollen from anemophilous terrestrial plant species; however, recent findings have expanded the definition of airborne eDNA to include a variety of eDNA sources, such as leaf and flower fragments. While methods for capturing pollen are well studied, there is less known about how to best analyze and capture more broadly defined bulk airborne eDNA samples. Therefore, this study aimed to identify efficient techniques for the extraction and amplification of airborne eDNA and how best to capture these samples. First, we collected samples using Big Spring Number Eight dust traps and quantified the influence of three different extraction methods (cetrimonium bromide‐chloroform, DNeasy Plant Maxi Kit, and DNeasy PowerPlant Pro DNA Isolation Kit) and two global plant primer sets (targeting the trnL and ITS2 genes) on quantitative polymerase chain reaction (qPCR)‐based terrestrial plant detection. Additionally, we examined how best to capture airborne eDNA by comparing the performance of three difference passive dust collectors (Big Spring Number Eight, Modified Wilson and Cooke, and Marble dust collectors). We found that the detection of airborne eDNA was significantly influenced by both the extraction methods employed and choice of qPCR primer. Additionally, we found that all three traps preformed similarly but the Big Spring Number Eight dust traps trended as consistently one of the most effective, shedding light on the nonhomogeneous nature of airborne eDNA. This study represents the first methodology paper focusing on airborne eDNA as a bulk environmental sample containing more than just pollen. In the future, additional research should examine more about the ecology of airborne eDNA (origin, state, transport, fate), explore active dust collectors compared to the passive traps used here, and develop the application of metabarcoding for airborne eDNA analysis.

In California, USA, coastal sage scrub (CSS) vegetation is being converted to exotic annual grassland, and several causes have been suggested. In order to investigate the importance of environmental variables in the conversion and recovery of CSS, particularly nitrogen deposition within the context of historical fire intervals, we employed an information theoretic approach. Prior studies have not assessed both conversion and recovery, and did not analyze nitrogen critical load for vegetation type conversion. We included measures of climate, topography, vegetation, land use, nitrogen deposition, and fire in our analysis, and found that 34% of CSS study sites were converted to exotic grassland between 1930 and 2009. Converted sites had higher nitrogen deposition with a critical load of 11 kg N ha−1 yr −1, also had shallower slopes, and were more west-facing. A smaller number of sites (24%) recovered to CSS, and these sites had about 2.5 times more CSS and 4.5 times less grassland in the surrounding landscape. CSS conservation and restoration efforts are most likely to be successful when focused on sites with <11.0 kg N ha−1 yr −1 and low invasion of exotic grasses. Analyses such as this that identify important threats may be useful in region-wide plans to conserve unique vegetation types

The increase of tree density in forests of the American Southwest promotes extreme fire events, understory biodiversity losses, and degraded habitat conditions for many wildlife species. To ameliorate these changes, managers and scientists have begun planning treatments aimed at reducing fuels and increasing understory biodiversity. However, spatial variability in tree density across the landscape is not well-characterized, and if better known, could greatly influence planning efforts. We used reflectance values from individual Landsat 8 bands (bands 2, 3, 4, 5, 6, and 7) and calculated vegetation indices (difference vegetation index, simple ratios, and normalized vegetation indices) to estimate tree density in an area planned for treatment in the Jemez Mountains, New Mexico, characterized by multiple vegetation types and a complex topography. Because different vegetation types have different spectral signatures, we derived models with multiple predictor variables for each vegetation type, rather than using a single model for the entire project area, and compared the model-derived values to values collected from on-the-ground transects. Among conifer-dominated areas (73% of the project area), the best models (as determined by corrected Akaike Information Criteria (AICc)) included Landsat bands 2, 3, 4, and 7 along with simple ratios, normalized vegetation indices, and the difference vegetation index (R² values for ponderosa: 0.47, piñon-juniper: 0.52, and spruce-fir: 0.66). On the other hand, in aspen-dominated areas (9% of the project area), the best model included individual bands 4 and 2, simple ratio, and normalized vegetation index (R² value: 0.97). Most areas dominated by ponderosa, pinyon-juniper, or spruce-fir had more than 100 trees per hectare. About 54% of the study area has medium to high density of trees (100–1000 trees/hectare), and a small fraction (4.5%) of the area has very high density (>1000 trees/hectare). Our results provide a better understanding of tree density for identifying areas in need of treatment and planning for more effective treatment. Our analysis also provides an integrated method of estimating tree density across complex landscapes that could be useful for further restoration planning.

Urban green spaces provide many benefits, including to human wellbeing, ecosystem services, and urban wildlife. Thus, there are many reasons to green up urban spaces, especially by using native species. Furthermore, urban green spaces are suited to enhancing biodiversity without negatively impacting food or fiber production. Municipalities and private landowners invest substantially in landscaping and its maintenance. However, much of that outlay supports non-native plants that may be less adapted to local conditions such as rainfall patterns and temperature ranges, thus having greater resource requirements, as well as being less supportive of native wildlife and possessing a greater potential of becoming invasive. Here, we explore ways to increase the use of native plant species in urban settings to reduce the need for watering or chemical application, enhance the support of native species, and reduce the risk of invasion to urban and ex-urban habitats. We identify three main impediments: the perception of native species as less aesthetically pleasing, the availability of native plants in the nursery industry, and the willingness of policymakers to take supportive measures. We propose methods to address all three, providing successful examples from a number of US localities and a case study that demonstrates what drivers might exist and what actions remain to be taken.

Conservation traditionally focuses on at-risk species and relatively intact ecosystems. As the human population and our global impact have risen, many more species and ecosystems are at risk and fewer intact ecosystems remain, with urbanization being a major contributing factor. Cities and their inhabitants are here to stay, and the prevalence of urbanization, often in the vicinity of areas of high conservation value, requires reconsideration of the conservation value of urban ecosystems and urban green spaces. Our aim is to explore the practical aspects of such actions. Urban ecosystem regeneration will require the incorporation of strategies for urban ecosystem regeneration into an overall conservation policy. The novel paradigm of urban ecosystem regeneration, advocated here, maximizes the capacity of urban spaces to support biodiversity while reducing undesirable outcomes and enhancing human wellbeing. The potential for cities to exacerbate biological invasion, climate change, and other ecosystem-degrading factors requires particular attention in devising a strategy for conservation in urban spaces, made essential by the predicted further spread of cities across the globe.