Drivers of prohibited natural resource collection in Chitwan National Park, Nepal.

Protected areas (PAs) are critical for achieving conservation, economic and development goals, but the factors that lead households to engage in prohibited resource collection in PAs are not well understood. We examine collection behaviours in community forests and the protected Chitwan National Park in Chitwan, Nepal. Our approach incorporates household and ecological data, including structured interviews, spatially explicit data on collection behaviours measured with computer tablets and a systematic field survey of invasive species.

Coupled abiotic-biotic cycling of nitrous oxide in tropical peatlands.

Atmospheric nitrous oxide (NO) is a potent greenhouse gas thought to be mainly derived from microbial metabolism as part of the denitrification pathway. Here we report that in unexplored peat soils of Central and South America, NO production can be driven by abiotic reactions (≤98%) highly competitive to their enzymatic counterparts. Extracted soil iron positively correlated with in situ abiotic NO production determined by isotopic tracers.

Water and nitrogen shape winter annual plant diversity and community composition in near-urban Sonoran Desert preserves.

Increased nitrogen (N) deposition threatens global biodiversity, but its effects in arid urban ecosystems are not well studied. In addition to altered N availability, urban environments also experience increases in other pollutants, decreased population connectivity, and altered biotic interactions, which can further impact biodiversity. In deserts, annual plant communities make up most of the plant diversity, support wildlife, and contribute to nutrient cycling and ecosystem processes.

Residential yard management and landscape cover affect urban bird community diversity across the continental USA.

Urbanization has a homogenizing effect on biodiversity and leads to communities with fewer native species and lower conservation value. However, few studies have explored whether or how land management by urban residents can ameliorate the deleterious effects of this homogenization on species composition. We tested the effects of local (land management) and neighborhood-scale (impervious surface and tree canopy cover) features on breeding bird diversity in six US metropolitan areas that differ in regional species pools and climate.

Municipal regulation of residential landscapes across US cities: Patterns and implications for landscape sustainability.

Local regulations on residential landscapes (yards and gardens) can facilitate or constrain ecosystem services and disservices in cities. To our knowledge, no studies have undertaken a comprehensive look at how municipalities regulate residential landscapes to achieve particular goals and to control management practices. Across six U.

Residential household yard care practices along urban-exurban gradients in six climatically-diverse U.S. metropolitan areas.

Residential land is expanding in the United States, and lawn now covers more area than the country's leading irrigated crop by area. Given that lawns are widespread across diverse climatic regions and there is rising concern about the environmental impacts associated with their management, there is a clear need to understand the geographic variation, drivers, and outcomes of common yard care practices. We hypothesized that 1) income, age, and the number of neighbors known by name will be positively associated with the odds of having irrigated, fertilized, or applied pesticides in the last year, 2) irrigation, fertilization, and pesticide application will vary quadratically with population density, with the highest odds in suburban areas, and 3) the odds of irrigating will vary by climate, but fertilization and pesticide application will not.

Climate and lawn management interact to control C plant distribution in residential lawns across seven U.S. cities.

In natural grasslands, C plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C vs. C photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs.

Soil-targeted interventions could alleviate locust and grasshopper pest pressure in West Africa.

Agricultural land use has intended and unintended consequences for human livelihoods through feedbacks within coupled human and natural systems. In Senegal, West Africa, soils are a vital resource for livelihoods and food security in smallholder farming communities. In this study, we explored the connections among land use, soil conditions, plant nutrient content, and the abundance of several locust and grasshopper species.

Mixed method approach to assess atmospheric nitrogen deposition in arid and semi-arid ecosystems.

Arid and semi-arid ecosystems (aridlands) cover a third of Earth's terrestrial surface and contain organisms that are sensitive to low level atmospheric pollutants. Atmospheric nitrogen (N) inputs to aridlands are likely to cause changes in plant community composition, fire frequency, and carbon cycling and storage. However, few studies have documented long-term rates of atmospheric N inputs in aridlands because dry deposition is technically difficult to quantify, and extensive sampling is needed to capture fluxes with spatially and temporally heterogeneous rainfall patterns.

Carbon lost and carbon gained: a study of vegetation and carbon trade-offs among diverse land uses in Phoenix, Arizona.

Human modification and management of urban landscapes drastically alters vegetation and soils, thereby altering carbon (C) storage and rates of net primary productivity (NPP). Complex social and ecological processes drive vegetation cover in cities, leading to heterogeneity in C dynamics depending on regional climate, land use, and land cover. Recent work has demonstrated homogenization in ecological processes within human-dominated landscapes (the urban convergence hypothesis) in soils and biotic communities.

Ammonia-oxidizing archaea respond positively to inorganic nitrogen addition in desert soils.

In soils, nitrogen (N) addition typically enhances ammonia oxidation (AO) rates and increases the population density of ammonia-oxidizing bacteria (AOB), but not that of ammonia-oxidizing archaea (AOA). We asked if long-term inorganic N addition also has similar consequences in arid land soils, an understudied yet spatially ubiquitous ecosystem type. Using Sonoran Desert top soils from between and under shrubs within a long-term N-enrichment experiment, we determined community concentration-response kinetics of AO and measured the total and relative abundance of AOA and AOB based on amoA gene abundance.

Assessing the homogenization of urban land management with an application to US residential lawn care.

Changes in land use, land cover, and land management present some of the greatest potential global environmental challenges of the 21st century. Urbanization, one of the principal drivers of these transformations, is commonly thought to be generating land changes that are increasingly similar. An implication of this multiscale homogenization hypothesis is that the ecosystem structure and function and human behaviors associated with urbanization should be more similar in certain kinds of urbanized locations across biogeophysical gradients than across urbanization gradients in places with similar biogeophysical characteristics.

Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert.

Rates of nitrogen (N) deposition have increased in arid and semiarid ecosystems, but few studies have examined the impacts of long-term N enrichment on ecological processes in deserts. We conducted a multiyear, nutrient-addition study within 15 Sonoran Desert sites across the rapidly growing metropolitan area of Phoenix, Arizona (USA). We hypothesized that desert plants and soils would be sensitive to N enrichment, but that these effects would vary among functional groups that differ in terms of physiological responsiveness, proximity to surface N sources, and magnitude of carbon (C) or water limitation.

The globalization of nitrogen deposition: consequences for terrestrial ecosystems.

The sources and distribution of anthropogenic nitrogen (N), including N fertilization and N fixed during fossil-fuel combustion, are rapidly becoming globally distributed. Responses of terrestrial ecosystems to anthropogenic N inputs are likely to vary geographically. In the temperate zone, long-term N inputs can lead to increases in plant growth and also can result in over-enrichment with N, eventually leading to increased losses of N via solution leaching and trace-gas emissions, and in some cases, to changes in species composition and to ecosystem decline.