Search for: All records

Launched in 2006 with support from the National Science Foundation (NSF) and leveraged by the CAP LTER, the Carbon and Nitrogen deposition (CNdep) project sought to answer the fundamental question of whether elemental cycles in urban ecosystems are qualitatively different from those in non-urban ecosystems. Ecosystem scientists, atmospheric chemists, and biogeochemists tested the hypothesis that distinct biogeochemical pathways result from elevated inorganic nitrogen and organic carbon deposition from the atmosphere to the land. To test the hypothesis, scientists examined the responsiveness of Sonoran desert ecosystems to nutrient enrichment by capitalizing on a gradient of atmospheric deposition in and around the greater Phoenix metropolitan area. Fifteen desert study sites were established, with five locations each west and east of the urban core, and in the urban core in desert preserves. In addition to the gradient of atmospheric deposition in and around the urban core, select study plots at each of the fifteen desert locations receive amendments of nitrogen, phosphorus, or nitrogen + phosphorus fertilizer. Measured variables include soil properties, perennial and annual plant growth, and atmospheric deposition of nitrogen. At the close of the initial grant period, the CAP LTER assumed responsibility for the project, renamed the Desert Fertilization Experiment, which provides a remarkable platform to study the long-term effects of nutrient enrichment on desert ecosystem properties. 

The Ecological Survey of Central Arizona (ESCA) is an extensive field survey and integrated inventory designed to capture key ecological indicators of the CAP LTER study area consisting of the urbanized, suburbanized, and agricultural areas of metropolitan Phoenix and the surrounding Sonoran desert. The survey is conducted every five years at approximately 200 sample plots (30m x 30m) that were located randomly using a tessellation-stratified, dual-density sampling design. Study plots cover habitats throughout the CAP LTER study area ranging from native Sonoran desert sites to residential yards to an airport tarmac. In 2010, the survey was expanded to include an assessment of residential parcels overlapping the survey plot at sites in residential areas. Many of the same variables that are measured in the 30m x 30m survey plot are measured in the parcel, including an inventory of perennial plants, and the biovolume of trees. In addition, a detailed assessment of characteristics of the parcel is performed. Investigators interested in data from the broader Ecological Survey of Central Arizona that includes all survey plots can find those data in the Environmental Data Initiative data repository at [this](https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-cap&identifier=652) link. 

The CAP LTER maintains two micrometeorological stations (10-m height) in the greater Phoenix metropolitan area, including at Lost Dutchman State Park and near the Desert Botanical Garden at Papago Park. The local terrain at both sites is flat or gently sloping Sonoran desert, and the vegetation canopy consists of patchy coverage of desert shrubs and trees. The dominant vegetation species include bursage (*Ambrosia deltoidea*) and creosote bush (*Larrea tridentata*), while minor species include palo verde (*Parkinsonia microphylla*) and saguaro cactus (*Carnegiea gigantea*). Wind speed and direction, incoming solar radiation, air temperature, relative humidity, and precipitation have been monitored nearly continuously since the fall of 2010. Each variable is measured every 5 seconds and the average (or total for precipitation and total solar radiation) saved to a data logger every 10 minutes. 

Abstract Cities support abundant human and wildlife populations that are shaped indirectly and directly by human decisions, often resulting in unequal access to environmental services and accessible open spaces. Urban land cover drives biodiversity patterns across metropolitan areas, but at smaller scales that matter to local residents, neighborhood socio‐cultural factors can influence the presence and abundance of wildlife. Neighborhood income is associated with plant and animal diversity in some cities, but the influence of other social variables is less well understood, especially across desert ecosystems. We explored wildlife distribution across gradients of neighborhood ethnicity in addition to income and landscape characteristics within residential areas of metropolitan Phoenix, Arizona, USA. Utilizing data from 38 wildlife cameras deployed in public parks and undeveloped open spaces within or near suburban neighborhoods, we estimated occupancy and activity patterns of common mammal species, including species native to the Sonoran Desert (coyote [Canis latrans] and desert cottontail rabbit [Sylvilagus audubonii]), and non‐native domestic cat (Felis catus). Neighborhood ethnicity (percentage of Latino residents) appeared to exhibit a negative relationship with occupancy for coyotes and cottontail rabbits. Additionally, daily activity patterns of coyotes occurred later in the evenings and mornings in neighborhoods with higher proportions of Latino residents, but activity was unaffected by differences in neighborhood income. This study is one of the first to show that social‐ecological mechanisms associated with patterns of neighborhood ethnicity as well as income may help to shape wildlife distribution in cities. These findings have implications for equitable management and provisioning of ecosystem services for urban residents and highlight the importance of considering a range of social covariates to better understand biodiversity outcomes in urban and urbanizing areas. 

IntroductionHuman-wildlife coexistence in cities depends on how residents perceive and interact with wildlife in their neighborhoods. An individual’s attitudes toward and responses to wildlife are primarily shaped by their subjective cognitive judgments, including multi-faceted environmental values and perceptions of risks or safety. However, experiences with wildlife could also positively or negatively affect an individual’s environmental attitudes, including their comfort living near wildlife. Previous work on human-wildlife coexistence has commonly focused on rural environments and on conflicts with individual problem species, while positive interactions with diverse wildlife communities have been understudied. MethodsGiven this research gap, we surveyed wildlife attitudes of residents across twelve neighborhoods in the Phoenix Metropolitan Area, AZ to ask: how do the environments in which residents live, as well as their values, identities, and personal characteristics, explain the degree to which they are comfortable living near different wildlife groups (coyotes, foxes, and rabbits)? ResultsWe found that residents who were more comfortable living near wildlife commonly held pro-wildlife value orientations, reflecting the expectation that attitudes toward wildlife are primarily driven be an individual’s value-based judgements. However, attitudes were further influenced by sociodemographic factors (e.g., pet ownership, gender identity), as well as environmental factors that influence the presence of and familiarity with wildlife. Specifically, residents living closer to desert parks and preserves were more likely to have positive attitudes toward both coyotes and foxes, species generally regarded by residents as riskier to humans and domestic animals. DiscussionBy improving understanding of people’s attitudes toward urban wildlife, these results can help managers effectively evaluate the potential for human-wildlife coexistence through strategies to mitigate risk and facilitate stewardship. 

Urban forests provide ecosystem services important for regulating climate, conserving biodiversity, and maintaining human well‐being. However, these forests vary in composition and physiological traits due to their unique biophysical and social contexts. This variation complicates assessing the functions and services of different urban forests. To compare the characteristics of the urban forest, we sampled the species composition and two externally sourced traits (drought tolerance and water‐use capacity) of tree and shrub species in residential yards, unmanaged areas, and natural reference ecosystems within six cities across the contiguous US. As compared to natural and unmanaged forests, residential yards had markedly higher tree and shrub species richness, were composed primarily of introduced species, and had more species with low drought tolerance. The divergence between natural and human‐managed areas was most dramatic in arid climates. Our findings suggest that the answer to the question of “what is an urban forest” strongly depends on where you look within and between cities. 

Introduction Integrated social and ecological processes shape urban plant communities, but the temporal dynamics and potential for change in these managed communities have rarely been explored. In residential yards, which cover about 40% of urban land area, individuals make decisions that control vegetation outcomes. These decisions may lead to relatively static plant composition and structure, as residents seek to expend little effort to maintain stable landscapes. Alternatively, residents may actively modify plant communities to meet their preferences or address perceived problems, or they may passively allow them to change. In this research, we ask, how and to what extent does residential yard vegetation change over time? Methods We conducted co-located ecological surveys of yards (in 2008, 2018, and 2019) and social surveys of residents (in 2018) in four diverse neighborhoods of Phoenix, Arizona. Results 94% of residents had made some changes to their front or back yards since moving in. On average, about 60% of woody vegetation per yard changed between 2008 and 2018, though the number of species present did not differ significantly. In comparison, about 30% of woody vegetation changed in native Sonoran Desert reference areas over 10 years. In yards, about 15% of woody vegetation changed on average in a single year, with up to 90% change in some yards. Greater turnover was observed for homes that were sold, indicating a “pulse” of management. Additionally, we observed greater vegetation turnover in the two older, lawn-dominated neighborhoods surveyed despite differences in neighborhood socioeconomic factors. Discussion These results indicate that residential plant communities are dynamic over time. Neighborhood age and other characteristics may be important drivers of change, while socioeconomic status neither promotes nor inhibits change at the neighborhood scale. Our findings highlight an opportunity for management interventions, wherein residents may be open to making conservation-friendly changes if they are already altering the composition of their yards. 

ABSTRACT. Urbanisation has led to increasing homogenization of plant communities across cities. However, it is unclear whether these patterns extend to cosmopolitan plant species at the genetic level. We examined genome‐wide genetic patterns in six widespread plant species (three Poaceae and three Asteraceae) across five cities in the USA (Boston, Baltimore, Minneapolis‐St. Paul, Phoenix, and Los Angeles) using reduced‐representation sequencing. We assessed genetic structure, differentiation, and patterns of isolation by distance (IBD) and environment (IBE) to determine if species were genetically homogeneous or differentiated by city, percentage of impervious surface, or both. Most species exhibited limited population structure overall, withPoa annua(annual bluegrass),Taraxacum officinale(dandelion), andCynodon dactylon(Bermuda grass) showing no significant genetic differentiation among cities, a pattern consistent with high gene flow mediated by human activity. Notable exceptions included city‐level differences inErigeron canadensis(horseweed) andLactuca serriola(prickly lettuce), especially in Phoenix. We also observed low genetic diversity inDigitaria sanguinalis(crabgrass) from Phoenix, suggesting recent founder effects or selection via environmental filtering.Erigeron canadensis,the only native species studied, displayed stronger differentiation by city, along with significant isolation by temperature and distance. Among all species, we found no evidence for population structure by impervious surface. Our findings indicate that widespread population genetic structure patterns of cosmopolitan plants are likely to depend more on species attributes (e.g., self‐compatibility) and human‐mediated dispersal than on urbanisation per se.