Tropical savanna and forest are recognized to represent alternate stable states, primarily determined by feedbacks with fire. Vegetation-fire dynamics in each of these vegetation types largely the influence on fire behavior, as well effects behavior tree mortality, topkill (defined here complete death aerial biomass, regardless whether plant recovers resprouting), rate growth resprouts. We studied effect three savanna-forest boundaries central Brazil. Fire intensity was greater than forest,...

Abstract The higher flammability of tropical savanna, compared with forest, plays a critical role in mediating vegetation‐environment feedbacks, alternate stable states, and ultimately, the distribution these two biomes. Multiple factors contribute to this difference flammability, including microclimate, fuel amount type. To understand transition we studied characteristics microclimate across eight savanna–forest boundaries south‐central Brazil. At each boundary, environment was monitored...

Questions: Has fire suppression relaxed barriers to the exchange of species between savanna and forest? Do all or a subset participate in this exchange? Would current vegetation structure persist if were cease? Location: A gallery forest edge Cerrado region central Brazil that burned only once past 35 years. Methods: Density tree seedlings, saplings adults, leaf area index (LAI), basal diameter surveyed 12, 10 m × 70 transects centred on perpendicular forest–savanna boundary. Community...

Biological soil crusts (biocrusts), comprised of mosses, lichens, and cyanobacteria, are key components to many dryland communities. Climate change other anthropogenic disturbances thought cause a decline in mosses yet few long-term studies exist track potential shifts these sensitive soil-surface Using unique observational dataset from temperate with initial observations dating back 1967, we examine the effects 53 y observed environmental variation Bromus tectorum invasion on biocrust...

Global dryland vegetation communities will likely change as ongoing drought conditions shift regional climates towards a more arid future. Additional aridification of drylands can impact plant and ground cover, biogeochemical cycles, plant-soil feedbacks, yet how when these crucial ecosystem components respond to intensification requires further investigation. Using long-term precipitation reduction experiment (35% reduction) conducted across the Colorado Plateau spanning 10 years into 20+...

Abstract Drylands have low nitrogen stocks and are predicted to be sensitive modest increases in reactive availability, but direct evidence that atmospheric deposition will sustained effects on dryland ecosystems is sparse conflicting. We used three long‐running situ simulation experiments a complementary laboratory incubation experiment address fundamental questions about how inputs affect drylands: (1) What the long‐ short‐term consequences of for biogeochemical ecosystem properties?; (2)...

ABSTRACT The potential distribution of alien species in a novel habitat often is difficult to predict because factors limiting distributions may be unique the new locale. Eragrostis lehmanniana perennial grass purposely introduced from South Africa Arizona, USA 1930s; by 1980s, it had doubled its extent. Based on environmental characteristics associated with and native range, researchers believed that E. reached limits early 1990s. We collected data locations various land management agencies...

Landscape metrics are a standard tool in the study and monitoring of landscape pattern change, but their statistical properties behaviour across range classification schemes landscapes, as well sensitivity to changing patterns, still not fully understood. We therefore investigated 24 number land cover classes for three Arizona landscapes with different spatial patterns. To do so, we applied unsupervised remotely sensed data two nominal resolutions generate maps containing 2–35 classes....

ABSTRACT Aim Native plant communities are susceptible to climate anomalies, which would favour the invasion of non‐native species. However, anomalies may also provide opportunities for detecting plants at a regional scale using remote sensing. Based on this mechanism, we propose direct and effective sensing approach map abundance South African Eragrostis lehmanniana Nees (Lehmann lovegrass), highly invasive, in desert grasslands southwestern North America. Location The grassland Fort...

Over the past several decades, one of most significant changes in semi‐desert grasslands southwestern US has been invasion South African grass Eragrostis lehmanniana. The objective this study was to characterize phenology systems occupied by E. lehmanniana and/or native grasses using time‐series field observations and Moderate Resolution Imaging Spectroradiometer Normalized Difference Vegetation Index (MODIS NDVI) brightness (red near‐infrared reflectance) data. Results demonstrated that it...

Abstract Aim Using a long‐term data set we investigated the response of semi‐desert grasslands to altered disturbance regimes in conjunction with climate patterns. Specifically, were interested non‐native grass ( Eragrostis lehmanniana ), mesquite Prosopis velutina and native species reintroduction fire removal livestock. Location The study site is located on 45,360‐ha Buenos Aires National Wildlife Refuge (31°32′ N, 110°30′ W) southern Arizona, USA. In 1985, livestock removed prescribed...

Understanding the resilience of ecosystems globally is hampered by complex and interacting drivers change characteristic Anthropocene. This true for drylands western US, where widespread alteration disturbance regimes spread invasive non-native species occurred with westward expansion during 1800s, including introduction domestic livestock Bromus tectorum, an annual grass. In addition, this region has experienced a multi-decadal drought not seen at least 1200 years potentially large impacts...

This note describes the addition of 64 native and 8 exotic species to known vascular flora Appleton-Whittell Research Ranch. Many additional were found in unique riparian areas or during detailed plot inventories are considered rare uncommon their abundance.