Search results for "Productivity."

Assessment of the Potential Evapotranspiration MODIS Product Using Ground Measurements in the Pampas

2018

Evapotranspiration is the hydrological variable of greatest relevance in the Argentina Pampas Region (APR). The estimation of potential evapotranspiration (PET) in this area becomes essential since primary productivity is directly linked to water availability. In order to evaluate the MOD16_A2 product of evapotranspiration (ET), a comparison with in situ measurements was conducted. We used ET data provided by the Oficina de Riesgo Agropecuario, corresponding to 24 stations placed in the region covering all seasons for the years 2012 to 2014. Results show an overestimation of 86% and 52% in Autumn-Winter and Spring-Summer, respectively. Mean Absolut Error (MAE) range between ±0.9 and ±2.1 mm…

Beyond APAR and NPQ: Factors Coupling and Decoupling SIF and GPP Across Scales

2021

The connection between solar-induced fluorescence (SIF) and vegetation gross primary productivity is being widely investigated across spatial, temporal, and biological scales, including: a) studies at the leaf [1], [2], plant canopy [2]–[4] or satellite pixel scale [5], [6], b) temporally with studies spanning from diurnal [7] to seasonal scales [1], [3], [5], and b) biologically with studies covering various plant functional types (PFTs), e.g., crops [4], [7], deciduous [8] or evergreen forests [1], [3], in response to different sources of stress.

Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradi…

2021

Subarctic lakes are getting warmer and more productive due to the joint effects of climate change and intensive land-use practices (e.g. forest clear-cutting and peatland ditching), processes that potentially increase leaching of peat- and soil-stored mercury into lake ecosystems. We sampled biotic communities from primary producers (algae) to top consumers (piscivorous fish), in 19 subarctic lakes situated on a latitudinal (69.0-66.5 degrees N), climatic (+3.2 degrees C temperature and +30% precipitation from north to south) and catchment land-use (pristine to intensive forestry areas) gradient. We first tested how the joint effects of climate and productivity influence mercury biomagnific…

Recreational noise pollution of traditional festivals reduces the juvenile productivity of an avian urban bioindicator.

2021

Noise is a pollutant of emergent concern for ecologists and conservation biologists. Recreational noise pollution, especially unpredictable and intermittent sounds, and its effects on wildlife and biodiversity have been poorly studied. Researchers have paid very little attention to the effect of noisy traditional festivals (fireworks and powder-guns). This study aimed to explore the effect of these recreational activities on the juvenile productivity of an urban avian bioindicator: the house sparrow. We studied five pairs of localities in the Valencia Region (E Spain) with noisy traditional festivals. Each pair was composed of one locality with festivals during the breeding season and the c…

Half a century of forest cover change along the Latvian-Russian border captured by object-based image analysis of Corona and Landsat TM/OLI data

2020

Abstract After 1991, major events, such as the collapse of socialism and the transition to market economies, caused land use change across the former USSR and affected forests in particular. However, major land use changes may have occurred already during Soviet rule, but those are largely unknown and difficult to map for large areas because 30-m Landsat data is not available prior to the 1980s. Our goal was to analyze the rates and determinants of forest cover change from 1967 to 2015 along the Latvian-Russian border, and to develop an object-based image analysis approach to compare forest cover based on declassified Corona spy satellite images from 1967 with that derived from Landsat 5 TM…

An assessment of the global impact of 21st century land use change on soil erosion

2017

Human activity and related land use change are the primary cause of accelerated soil erosion, which has substantial implications for nutrient and carbon cycling, land productivity and in turn, worldwide socio-economic conditions. Here we present an unprecedentedly high resolution (250 × 250 m) global potential soil erosion model, using a combination of remote sensing, GIS modelling and census data. We challenge the previous annual soil erosion reference values as our estimate, of 35.9 Pg yr−1 of soil eroded in 2012, is at least two times lower. Moreover, we estimate the spatial and temporal effects of land use change between 2001 and 2012 and the potential offset of the global application o…

Global Groundwater-Vegetation Relations

2017

Groundwater is an integral component of the water cycle, and it also influences the carbon cycle by supplying moisture to ecosystems. However, the extent and determinants of groundwater-vegetation interactions are poorly understood at the global scale. Using several high-resolution data products, we show that the spatial patterns of ecosystem gross primary productivity and groundwater table depth are correlated during at least one season in more than two-thirds of the global vegetated area. Positive relationships, i.e., larger productivity under shallower groundwater table, predominate in moisture-limited dry to mesic conditions with herbaceous and shrub vegetation. Negative relationships, …

Insolation cycles as a major control equatorial Indian Ocean primary production

1997

Analysis of a continuous sedimentary record taken in the Maldives indicates that strong primary production fluctuations (70 to 390 grams of carbon per square meter per year) have occurred in the equatorial Indian Ocean during the past 910,000 years. The record of primary production is coherent and in phase with the February equatorial insolation, whereas it shows diverse phase behavior with δ 18 O, depending on the orbital frequency (eccentricity, obliquity, or precession) examined. These observations imply a direct control of productivity in the equatorial oceanic system by insolation. In the equatorial Indian Ocean, productivity is driven by the wind intensity of westerlies, which is rel…

Productivity modes in the Mediterranean Sea during Dansgaard–Oeschger (20,000–70,000 yr ago) oscillations

2013

The study of planktonic organisms during abrupt climatic variations of the last glacial period (Dansgaard-Oeschger oscillations, D-O) may reveal important insights on climatic, oceanographic and biological interactions. Here we present planktic foraminifera and coccolithophore data collected at the Ocean Drilling Program Site 963 (Sicily Channel), with a mean sampling resolution of respectively 43.5 and 98.9. yr, over the interval between 70,000 and 20,000. yr ago. The paleoenvironmental reconstruction suggests that three different scenarios can be seen across each D-O cycle: 1. oligotrophic surface water and a deep thermocline for the early Interstadials; 2. a Deep Chlorophyll Maximum and …

2021

Abstract. The collection of modern, spatially extensive pollen data is important for the interpretation of fossil pollen assemblages and the reconstruction of past vegetation communities in space and time. Modern datasets are readily available for percentage data but lacking for pollen accumulation rates (PARs). Filling this gap has been the motivation of the pollen monitoring network, whose contributors monitored pollen deposition in modified Tauber traps for several years or decades across Europe. Here we present this monitoring dataset consisting of 351 trap locations with a total of 2742 annual samples covering the period from 1981 to 2017. This dataset shows that total PAR is influence…