Treesearch

Tropical savanna ecosystems play a major role in the seasonality of the global carbon cycle. However, their ability to store and sequester carbon is uncertain due to combined and intermingling effects of anthropogenic activities and climate change, which impact wildfire regimes and vegetation dynamics. Accurate measurements of tropical savanna vegetation aboveground biomass (AGB) over broad spatial scales are crucial to achieve effective carbon emission mitigation strategies. UAV-lidar is a new remote sensing technology that can enable rapid 3-D mapping of structure and related AGB in...

Extreme wildfires are a major environmental and socioeconomic threat across many regions worldwide. The limits of fire suppression-centred strategies have become evident even in technologically well-equipped countries, due to high-cost and a legacy of landscape transformations, yet with ultimately low-efficient solutions vis- `a-vis extreme fires. Many practitioners and policymakers thus increasingly recognize the need to develop novel, integrated fire management approaches that shift emphasis towards the root causes of extreme fires. Here we provide from the socioeconomic angle a collectiv...

Anthropogenic nitrogen (N) and sulfur (S) deposition can negatively affect ecosystem functions and lichen biomonitors can be a cost-effective way to monitor air pollution exposure across the landscape. Interior dry forests of the southwestern United States face increasing development pressures; however, this region differs from others with well-developed biomonitoring programs in having drier climates and a greater fraction of deposition delivered in dry forms. We measured throughfall N and S deposition at 12 sites in Utah and 10 in New Mexico and co-located collection of 6 lichen species....

Whitebark pine (Pinus albicaulis) (PIAL) is a proposed threatened species that plays a keystone ecological role in the Greater Yellowstone Ecosystem (GYE). Its population response to climate change is of high interest to managers because climate-induced declines may adversely affect critical ecosystem services that this species provides. While previous studies of reproductive size classes of the species have projected dramatic reductions in area of suitable habitat under climate warming scenarios, it has been suggested that the species can tolerate warmer and drier conditions if seedlings...

The interplay between top-down and bottom-up processes determines ecosystem productivity. Yet, the factors that mediate the balance between these opposing forces remain poorly understood. Furthering this challenge, complex and often cryptic factors like ecosystem engineering and trait-mediated interactions may play major roles in mediating the outcomes of top-down and bottom-up interactions. In semiarid grasslands of northeastern China, we conducted a large-scale, three-year experiment to evaluate how soil engineering by ants and plasticity in plants independently and jointly influenced...

Myrtle rust (MR) caused by Austropuccinia psidii is one of the most important diseases affecting eucalypt (Eucalyptus) plantations in Brazil. Over the years, selection and planting of MR-resistant clones has been the primary strategy for MR management. In May 2013, young trees of the GG100 hybrid (E. grandis × E. urophylla) clone - widely planted in Brazil and previously classified as resistant to MR - were infected by A. psidii in Minas Gerais, Brazil. In this study, artificial inoculations of a eucalypt clone set with differential reactions to A. psidii races were used to discover a new...

Identifying factors that create and maintain a hybrid zone is of great interest to ecology, evolution and, more recently, conservation biology. Here, we investigated the role of environmental features in shaping the spatial dynamics of a hybrid zone between the southern tigrina, Leopardus guttulus, and Geoffroy's cat, L. geoffroyi, testing for exogenous selection as the main force acting on its maintenance. These Neotropical felid species are mainly allopatric, with a restricted area of sympatry in the ecotone between the Atlantic Forest and Pampa biomes. As both biomes have experienced...

Average annual temperature over the contiguous United States has increased by 0.7 degrees Celsius (°C; 1.2 degrees Fahrenheit (°F) for the period 1986-2016 compared to 1901-1960 (Vose and others, 2017). Warming temperatures, increased frequency of heat waves, and possibly drought have likely contributed to longer fire seasons, more extreme fire weather, and consequently, larger amounts of sagebrush (Artemisia spp.) burned each year. Future climate warming and alterations in timing of seasonal precipitation may impact the distribution of sagebrush and invasive plants, and further increase...

Restoration of habitats that have been altered by anthropogenic and natural disturbance and the introduction of invasive plant species is a significant concern in sagebrush (Artemisia spp.) ecosystems. Restoration, broadly defined here to include rehabilitation and reclamation, is most feasible when objectives are clear, residual ecosystem components are present, and environmental conditions are favorable. However, severe loss of biotic diversity and ecosystem functioning creates substantial obstacles for recovery to original or even desirable alternative, stable vegetation states. This is...

Coniferous trees, principally juniper (Juniperus spp.) and pinyon pine (Pinus spp.), have increased considerably in cover and density in the western United States since European settlement with wide ranging consequences for sagebrush (Artemisia spp.) ecosystems. A continuum of vegetation types exists across the region, from conifer-encroached shrublands to persistent pinyon-juniper woodlands and savannas. This chapter focuses on the issue of conifer expansion into sagebrush shrublands and ensuing woodland succession, not the infill of persistent woodlands and savannas. Detrimental effects...