scholarly journals Tracking vegetation phenology across diverse North American biomes using PhenoCam imagery

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Andrew D. Richardson ◽  
Koen Hufkens ◽  
Tom Milliman ◽  
Donald M. Aubrecht ◽  
Min Chen ◽  
...  
Keyword(s):  
Climate Change ◽  
Vegetation Type ◽  
Digital Camera ◽  
Region Of Interest ◽  
Remote Sensing Data ◽  
Climate Change Impacts ◽  
Terrestrial Ecosystems ◽  
Vegetation Phenology ◽  
Phenological Model ◽  
Vegetation Activity

Abstract Vegetation phenology controls the seasonality of many ecosystem processes, as well as numerous biosphere-atmosphere feedbacks. Phenology is also highly sensitive to climate change and variability. Here we present a series of datasets, together consisting of almost 750 years of observations, characterizing vegetation phenology in diverse ecosystems across North America. Our data are derived from conventional, visible-wavelength, automated digital camera imagery collected through the PhenoCam network. For each archived image, we extracted RGB (red, green, blue) colour channel information, with means and other statistics calculated across a region-of-interest (ROI) delineating a specific vegetation type. From the high-frequency (typically, 30 min) imagery, we derived time series characterizing vegetation colour, including “canopy greenness”, processed to 1- and 3-day intervals. For ecosystems with one or more annual cycles of vegetation activity, we provide estimates, with uncertainties, for the start of the “greenness rising” and end of the “greenness falling” stages. The database can be used for phenological model validation and development, evaluation of satellite remote sensing data products, benchmarking earth system models, and studies of climate change impacts on terrestrial ecosystems.

scholarly journals Soil nitrogen cycle unresponsive to decadal long climate change in a Tasmanian grassland

2019 ◽  
Vol 147 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Tobias Rütting ◽  
Mark J. Hovenden
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Sink ◽  
Vegetation Type ◽  
Terrestrial Ecosystems ◽  
Soil N ◽  
Mineral N ◽  
N Dynamics ◽  
Terrestrial Carbon Sink ◽  
Soil Nitrogen Cycle

AbstractIncreases in atmospheric carbon dioxide (CO2) and global air temperature affect all terrestrial ecosystems and often lead to enhanced ecosystem productivity, which in turn dampens the rise in atmospheric CO2 by removing CO2 from the atmosphere. As most terrestrial ecosystems are limited in their productivity by the availability of nitrogen (N), there is concern about the persistence of this terrestrial carbon sink, as these ecosystems might develop a progressive N limitation (PNL). An increase in the gross soil N turnover may alleviate PNL, as more mineral N is made available for plant uptake. So far, climate change experiments have mainly manipulated one climatic factor only, but there is evidence that single-factor experiments usually overestimate the effects of climate change on terrestrial ecosystems. In this study, we investigated how simultaneous, decadal-long increases in CO2 and temperature affect the soil gross N dynamics in a native Tasmanian grassland under C3 and C4 vegetation. Our laboratory 15N labeling experiment showed that average gross N mineralization ranged from 4.9 to 11.3 µg N g−1 day−1 across the treatment combinations, while gross nitrification was about ten-times lower. Considering all treatment combinations, no significant effect of climatic treatments or vegetation type (C3 versus C4 grasses) on soil N cycling was observed.

Climate Change Impacts on Biodiversity in Arid and Semi-Arid Areas

2022 ◽  
pp. 578-602
Author(s):  
Hanane Boutaj ◽  
Aicha Moumni ◽  
Oumayma Nassiri ◽  
Abdelhak Ouled Aitouna
Keyword(s):  
Climate Change ◽  
Indirect Effects ◽  
Vegetation Type ◽  
Climate Change Impacts ◽  
Biodiversity Loss ◽  
Arid Zones ◽  
Local Extinctions ◽  
Ecological Tourism ◽  
Biodiversity Decline ◽  
Semi Arid

Considerable attention has been paid to climate change and its impacts on biodiversity. The climate change has caused several problems such as continuous ecosystem degradation and a resultant biodiversity decline. In addition, climate warming has a range of indirect effects through changes in vegetation type level and sea that affect physical and biological systems. This has also led to changes in the distribution of species, as well as reductions in the size of populations, or even local extinctions of these populations. Moreover, many species are disappearing with time due to climate change combined with the emergence of disease that develops and increases with time. These problems affect different biodiversity components that are close to collapse. This chapter explored the richness of biodiversity in arid and semi-arid zones. It is also illuminates the effects of climate change on distribution of biodiversity. The authors highlight the responses of biodiversity under climate change, in terms of species extinction, biodiversity loss, and the impacts of climate change to ecological tourism. Finally, the authors show how biodiversity can overcome the effect of climate change, by developing some systems that allow to them to survive and conservation of species and ecosystems.

scholarly journals Nitrogen cycles in terrestrial ecosystems: climate change impacts and mitigation

2016 ◽  
Vol 24 (2) ◽  
pp. 132-143 ◽  
Author(s):  
Zhenzhu Xu ◽  
Yanling Jiang ◽  
Guangsheng Zhou
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Anthropogenic Activities ◽  
Water Status ◽  
Climate Change Impacts ◽  
Terrestrial Ecosystems ◽  
N Deposition ◽  
N Balance ◽  
N Cycle ◽  
Change Factors

The nitrogen (N) cycle and N balance have primarily been modified by anthropogenic activities and environmental changes at various scales, including biological individual, ecosystem, local landscape, continental region, and global. These modifications have drastically affected the structures and functions of natural and agricultural ecosystems in terrestrial and aquatic areas. In this manuscript, we first present a modified view of the global N cycle that includes N transport, conversion, and exchange processes. Second, several crucial issues concerning N balance, including N deposition and excessive addition and the dynamics of N and other nutrients, are reviewed. Third, the effects of climate change factors, including water status, warming, and elevated CO2 concentrations, on N balance and the N cycle and their interactions within and with other environmental factors are outlined. Finally, intervention strategies for improving N balance and N cycling to address rapid continual climatic change and socio-economic development are presented and discussed. It is highlighted that the altered N balance and N cycle between the geosphere, biosphere, and atmosphere have produced the profoundly critical challenge of maintaining N levels within an appropriate range, which should be considered by relevant people and sectors, including researchers, managers, and policy makers from ecological, environmental, and sustainable development sectors.

scholarly journals Photoperiod controls vegetation phenology across Africa

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Tracy Adole ◽  
Jadunandan Dash ◽  
Victor Rodriguez-Galiano ◽  
Peter M. Atkinson
Keyword(s):  
Annual Variation ◽  
Climate Change Impacts ◽  
Terrestrial Ecosystems ◽  
Growing Season ◽  
Dominant Factor ◽  
Vegetation Phenology ◽  
Systematic Analysis ◽  
Vegetation Models ◽  
The Relationship

Abstract Vegetation phenology is driven by environmental factors such as photoperiod, precipitation, temperature, insolation, and nutrient availability. However, across Africa, there’s ambiguity about these drivers, which can lead to uncertainty in the predictions of global warming impacts on terrestrial ecosystems and their representation in dynamic vegetation models. Using satellite data, we undertook a systematic analysis of the relationship between phenological parameters and these drivers. The analysis across different regions consistently revealed photoperiod as the dominant factor controlling the onset and end of vegetation growing season. Moreover, the results suggest that not one, but a combination of drivers control phenological events. Consequently, to enhance our predictions of climate change impacts, the role of photoperiod should be incorporated into vegetation-climate and ecosystem modelling. Furthermore, it is necessary to define clearly the responses of vegetation to interactions between a consistent photoperiod cue and inter-annual variation in other drivers, especially under a changing climate.

scholarly journals Influences of Shifted Vegetation Phenology on Runoff Across a Hydroclimatic Gradient

2022 ◽  
Vol 12 ◽  
Author(s):  
Shouzhi Chen ◽  
Yongshuo H. Fu ◽  
Xiaojun Geng ◽  
Zengchao Hao ◽  
Jing Tang ◽  
...  
Keyword(s):  
Climate Change ◽  
Climatic Factors ◽  
Remote Sensing Data ◽  
River Basins ◽  
Gray Relational Analysis ◽  
Vegetation Phenology ◽  
Spring Phenology ◽  
Factors Affecting ◽  
Growing Season Length ◽  
Humid Region

Climate warming has changed vegetation phenology, and the phenology-associated impacts on terrestrial water fluxes remain largely unquantified. The impacts are linked to plant adjustments and responses to climate change and can be different in different hydroclimatic regions. Based on remote sensing data and observed river runoff of hydrological station from six river basins across a hydroclimatic gradient from northeast to southwest in China, the relative contributions of the vegetation (including spring and autumn phenology, growing season length (GSL), and gross primary productivity) and climatic factors affecting the river runoffs over 1982–2015 were investigated by applying gray relational analysis (GRA). We found that the average GSLs in humid regions (190–241 days) were longer than that in semi-humid regions (186–192 days), and the average GSLs were consistently extended by 4.8–13.9 days in 1982–2015 period in six river basins. The extensions were mainly linked to the delayed autumn phenology in the humid regions and to advanced spring phenology in the semi-humid regions. Across all river basins, the GRA results showed that precipitation (r = 0.74) and soil moisture (r = 0.73) determine the river runoffs, and the vegetation factors (VFs) especially the vegetation phenology also affected the river runoffs (spring phenology: r = 0.66; GSL: r = 0.61; autumn phenology: r = 0.59), even larger than the contribution from temperature (r = 0.57), but its relative importance is climatic region-dependent. Interestingly, the spring phenology is the main VF in the humid region for runoffs reduction, while both spring and autumn growth phenology are the main VFs in the semi-humid region, because large autumn phenology delay and less water supply capacity in spring amplify the effect of advanced spring phenology. This article reveals diverse linkages between climatic and VFs, and runoff in different hydroclimatic regions, and provides insights that vegetation phenology influences the ecohydrology process largely depending on the local hydroclimatic conditions, which improve our understanding of terrestrial hydrological responses to climate change.

scholarly journals Tracking vegetation phenology across diverse biomes using Version 2.0 of the PhenoCam Dataset

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Bijan Seyednasrollah ◽  
Adam M. Young ◽  
Koen Hufkens ◽  
Tom Milliman ◽  
Mark A. Friedl ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Climate Change Impacts ◽  
Quality Data ◽  
Digital Cameras ◽  
Vegetation Phenology ◽  
Phenological Data ◽  
Wide Range ◽  
Data Products ◽  
Version 2.0

Abstract Monitoring vegetation phenology is critical for quantifying climate change impacts on ecosystems. We present an extensive dataset of 1783 site-years of phenological data derived from PhenoCam network imagery from 393 digital cameras, situated from tropics to tundra across a wide range of plant functional types, biomes, and climates. Most cameras are located in North America. Every half hour, cameras upload images to the PhenoCam server. Images are displayed in near-real time and provisional data products, including timeseries of the Green Chromatic Coordinate (Gcc), are made publicly available through the project web page (https://phenocam.sr.unh.edu/webcam/gallery/). Processing is conducted separately for each plant functional type in the camera field of view. The PhenoCam Dataset v2.0, described here, has been fully processed and curated, including outlier detection and expert inspection, to ensure high quality data. This dataset can be used to validate satellite data products, to evaluate predictions of land surface models, to interpret the seasonality of ecosystem-scale CO2 and H2O flux data, and to study climate change impacts on the terrestrial biosphere.

scholarly journals Trends in Satellite-Observed Circumpolar Photosynthetic Activity from 1982 to 2003: The Influence of Seasonality, Cover Type, and Vegetation Density

2006 ◽  
Vol 10 (12) ◽  
pp. 1-19 ◽  
Author(s):  
Andrew G. Bunn ◽  
Scott J. Goetz
Keyword(s):  
Climate Change ◽  
Photosynthetic Activity ◽  
Vegetation Type ◽  
Statistical Tests ◽  
Process Models ◽  
Tree Cover ◽  
High Latitudes ◽  
Vegetation Density ◽  
Vegetation Activity ◽  
Forested Areas

Abstract Time series analyses of a 22-yr record of satellite observations across the northern circumpolar high latitudes were conducted, and trends in vegetation photosynthetic activity were assessed using a series of statistical tests. The results indicate that most of the northern circumpolar high latitudes (>85%) showed no significant trend in vegetation activity despite systematic climate warming during the period of analysis. Of the areas that did change, many showed the expected trends in “greening” of vegetation activity. There were, however, significant differences in the magnitude and even in the direction of trends when stratified by vegetation type and density. Tundra areas consistently and predominantly showed greening trends. Forested areas showed declines in activity (“browning”) in many areas, and these were systematically higher in areas with denser tree cover—whether deciduous or evergreen, needle- or broad-leafed. The seasonality of the trends was also distinct between vegetation types, with a divergence in trends between late spring and early summer (positive) versus late summer (negative) portions of the growing seasons in forested areas. In contrast, tundra and other predominantly herbaceous areas showed positive trends in all portions of the growing season. These results confirm recent findings across the high latitudes of North America and are supported by an increasing array of in situ measurements. They indicate that the boreal forest biome might be responding to climate change in previously unexpected ways, and point to a need for an expanded observational network, additional analysis of existing datasets (e.g., tree rings), and improvements in process models of ecosystem responses to climate change.

scholarly journals Ecological restoration and rising CO2 enhance carbon sink, counteracting climate change in northeastern China

2021 ◽  
Author(s):  
Binbin Huang ◽  
Fei Lu ◽  
Xiaoke Wang ◽  
Xing Wu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Ecological Restoration ◽  
Carbon Sink ◽  
Remote Sensing Data ◽  
Terrestrial Ecosystems ◽  
Source Control ◽  
Impact Of Climate Change ◽  
The Individual ◽  
Business As Usual ◽  
The Impact

Abstract The impact of climate change, rising CO2, land use/land cover change (LC) and land management (LM) on carbon cycle in terrestrial ecosystems has been widely reported. However, rare studies have been conducted to clarify the impact of climate change and rising CO2 on carbon sink contributed by ecological restoration projects (ERPs). To better understand the impact of climate change and rising CO2 on ERPs, we took the Beijing-Tianjin Sand Source Control Project (BTSSCP) zone as an example to set different scenarios to distinguish the confounding effects of these factors on regional carbon budget based on remote sensing data-driven model. Compared with business as usual (BAU), our results showed climate change caused carbon loss of 78.97 Tg. On the contrary, ERPs contributed approximately 199.88 Tg C sink in forest and grassland. Furthermore, rising CO2 also contributed an additional 107.80 Tg C sink. This study distinguished the individual effects of different factors, and clarified the net carbon sink contributed by ERPs and rising CO2 and their significance to enhance regional carbon sink and reverse adverse effects of climate change on carbon sink. Furthermore, ERPs can sequester carbon dioxide faster and more effectively compared with rising CO2.

scholarly journals The handbook for standardized field and laboratory measurements in terrestrial climate change experiments and observational studies (ClimEx)

2020 ◽  
Author(s):  
Aud Halbritter ◽  
Hans De Boeck ◽  
Vigdis Vandvik ◽  
Keyword(s):  
Climate Change ◽  
Best Practice ◽  
Climate Change Impacts ◽  
Terrestrial Ecosystems ◽  
Data Availability ◽  
Ecosystem Structure ◽  
Climate Change Research ◽  
Wide Range ◽  
Practice Methods ◽  
Response Variables

<p>Climate change is a world‐wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high‐quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis and upscaling. Many of these challenges relate to a lack of an established ‘best practice’ for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change.</p><p>To overcome these challenges, we collected best‐practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re‐use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The protocols are also available online on the ClimEx handbook webpage (https://climexhandbook.w.uib.no/) and we encourage scientists from the climate change research community to get involved, give us feedback and make suggestions for updates to specific protocols. We hope that this is a way to amend the protocols and extend the shelf life of the ClimEx Handbook.</p><p>The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re‐use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second‐order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world.</p>

scholarly journals Detection of Changes in Terrestrial Ecosystems of Ukraine Using Remote Sensing Data

2020 ◽  
Vol 29 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Vadym I. Lyalko ◽  
Inna F. Romanciuc ◽  
Lesia A. Yelistratova ◽  
Aleksandr A. Apostolov ◽  
Viktor M. Chekhniy
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Moisture Content ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Terrestrial Ecosystems ◽  
Quantitative Information ◽  
Extreme Weather Events ◽  
Natural Soil ◽  
Sensing Data

In recent years, Ukraine has been affected by climate change. This has led to frequent extreme weather events (heavy / high rains, floods, droughts, squalls). As a result of droughts, desertification is one of the most dangerous and transient consequences of modern climate change. The research is devoted to the diagnostic assessment of the modern climate of Ukraine. Remote sensing data and instrumental observations of 30 weather stations of Ukraine were used. Temperature increase was registered in the study area by all stations, which significantly affected the level of precipitation. At the moment there is not enough moisture for the Earth’s surface. Precipitation in Ukraine is currently characterized by an uneven distribution. It leads to accelerated processes of soil degradation and it’s fertility loss. The aim of the study was to identify areas prone to desertification using satellite imagery and meteorological observations. Over the past 17 years (2000-2017), the average air temperature in Ukraine has increased by 1.5 ºC. Particularly anomalous warming has been recorded in recent years, starting in 2015. During the XXI century, a slight decrease in precipitation was observed in Ukraine. Both a decrease in precipitation and an increase in temperature may lead to a decrease in soil moisture levels. According to ground meteorological data, the tendency of dryness in Ukraine was confirmed. Lack of water leads to prompt manifestation of this process. Water indexes were used to estimate the moisture content of surface soils. It is possible to assess the susceptibility of the desert area to climate change. Relevant quantitative information on water availability in Ukraine is provided. Two water indices (Normalized Difference Infrared Index NDII and Ratio Drought Index RDI) have been taken estimate the moisture content. It can be estimated from the MODIS MOD13C2 product data obtained from the MODIS satellite sensor and used for regional research. The main conclusion of this study is to determine the changes in natural terrestrial ecosystems in Ukraine. This was shown on the basis of temperature and humidity. Such trends may lead to changes in the biodiversity of the territory and loss of natural soil properties.

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