ADRIAN V. ROCHA results 22
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Functional diversity of Brazilian bees: revealing the unique patterns of the NeotropicsNARA Subscribed
Bees are essential for ecosystem functioning, pollinating many wild and crop plant species. Predicting which species are most vulnerable to global changes, and how their loss may impact ecosystems and human well-being, is critical. Comprehensive information on bee response and effect traits is fundamental to these assessments. However, the Raunkiærian shortfall—insufficient trait data—remains significant for bees, particularly...
Atmosphere, Vegetation, and Soil Water Coupling Determined by Stomatal Regulation of TranspirationNARA Subscribed
Stomatal regulation plays a critical role in controlling tree water loss and mediating atmosphere–vegetation–soil water coupling, yet the implications of species-specific differences in stomatal regulation on this coupling remain poorly understood. Drimys species possess primitive leaf anatomy with limited stomatal closure capacity, while Nothofagus exhibits more effective stomatal control. We compared multi-year sap flux data...
LandFrag : A Dataset to Investigate the Effects of Forest Loss and Fragmentation on BiodiversityNARA Subscribed
Motivation The accelerated and widespread conversion of once continuous ecosystems into fragmented landscapes has driven ecological research to understand the response of biodiversity to local (fragment size) and landscape (forest cover and fragmentation) changes. This information has important theoretical and applied implications, but is still far from complete. We compiled the most comprehensive and updated database to inves...
Small herbivores with big impacts: Tundra voles ( Microtus oeconomus ) alter post‐fire ecosystem dynamicsNARA Subscribed
Fire is an important ecological disturbance that can reset ecosystems and initiate changes in plant community composition, ecosystem biogeochemistry, and primary productivity. As herbivores rely on primary producers for food, changes in vegetation may alter plant–herbivore interactions with important—but often unexplored—feedbacks to ecosystems. Here we examined the impact of post‐fire changes in plant community composition an...
Global maps of soil temperatureNARA Subscribed
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1‐km 2 r...
Alleviation of nutrient co‐limitation induces regime shifts in post‐fire community composition and productivity in Arctic tundraNARA Subscribed
Recent unprecedented fires in the Arctic during the past two decades have indicated a pressing need to understand the long‐term ecological impacts of fire in this biome. Anecdotal evidence suggests that tundra fires can induce regime shifts that change tussock tundra to more shrub‐dominated ecosystems. However, the ecological mechanisms regulating these shifts are poorly understood, but are hypothesized to involve changes to n...
Climate change is creating widespread ecosystem disturbance across the permafrost zone, including a rapid increase in the extent and severity of tundra wildfire. The expansion of this previously rare disturbance has unknown consequences for lateral nutrient flux from terrestrial to aquatic environments. Lateral loss of nutrients could reduce carbon uptake and slow recovery of already nutrient‐limited tundra ecosystems. To inve...
A Century of Forest Regrowth and Snow Loss Alters the Cooling Effect of Historical Land Use in the Upper MidwestNARA Subscribed
Anthropogenic land use affects climate by altering the energy balance of the Earth’s surface. In temperate regions, cooling from increased albedo is a common result of historical land-use change. However, this albedo cooling effect is dependent mainly on the exposure of snow cover following forest canopy removal and may change over time due to simultaneous changes in both land cover and snow cover. In this paper, we combine mo...
Solar‐induced chlorophyll fluorescence (SIF) has been increasingly used as a proxy for terrestrial gross primary productivity (GPP). Previous work mainly evaluated the relationship between satellite‐observed SIF and gridded GPP products both based on coarse spatial resolutions. Finer resolution SIF (1.3 km × 2.25 km) measured from the Orbiting Carbon Observatory‐2 (OCO‐2) provides the first opportunity to examine the SIF–GPP r...
Disturbance legacies and climate jointly drive tree growth and mortality in an intensively studied boreal forestNARA Subscribed
Most North American forests are at some stage of post‐disturbance regrowth, subject to a changing climate, and exhibit growth and mortality patterns that may not be closely coupled to annual environmental conditions. Distinguishing the possibly interacting effects of these processes is necessary to put short‐term studies in a longer term context, and particularly important for the carbon‐dense, fire‐prone boreal forest. The go...
Postfire energy exchange in arctic tundra: the importance and climatic implications of burn severityNARA Subscribed
Fires produce land cover changes that have consequences for surface energy balance and temperature. Three eddy covariance towers were setup along a burn severity gradient (i.e. Severely, Moderately, and Unburned tundra) to determine the effect of fire and burn severity on arctic tundra surface energy exchange and temperature for three growing seasons (2008–2010) following the 2007 Anaktuvuk River fire. The three sites were wel...
An eddy covariance mesonet to measure the effect of forest age on land–atmosphere exchangeNARA Subscribed
We deployed a mesonet of year‐round eddy covariance towers in boreal forest stands that last burned in ∼1850, ∼1930, 1964, 1981, 1989, 1998, and 2003 to understand how CO 2 exchange and evapotranspiration change during secondary succession. We used MODIS imagery to establish that the tower sites were representative of the patterns of secondary succession in the region, and Landsat images to show that the individual stands have...
On linking interannual tree ring variability with observations of whole‐forest CO 2 fluxNARA Subscribed
We used a 10‐year record of the CO 2 flux by an old growth boreal forest in central Manitoba (the Northern Old Black Spruce Site (NOBS)), a ∼150‐year‐old Picea mariana [Mill.] stand) to determine whether and how whole‐forest CO 2 flux is related to tree ring width. We compared a 37‐year ring width chronology collected at NOBS to a second chronology that was collected at a nearby Black Spruce stand with a different disturbance...
Photosynthetic and Water Use Efficiency Responses to Diffuse Radiation by an Aspen-Dominated Northern Hardwood ForestNARA Subscribed
Clouds can exert strong effects on ecosystem CO2 and water vapor fluxes and may be important determinants of terrestrial primary production. We used three years of eddy-covariance and meteorological data from an aspen-dominated northern hardwood forest in Michigan to investigate how canopy photosynthesis (P), evapotranspiration (E), and water use efficiency (WUE) responded to changes in cloud cover, or the proportion of diffus...
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