Spatial and Seasonal Patterns in Vegetation Growth-Limiting Factors over Europe

Abstract

Water and energy are recognized as the most influential climatic vegetation growth-limiting factors. These factors are usually measured from ground meteorological stations. However, since both vary in space, time, and scale, they can be assessed by satellite-derived biophysical indicators. Energy, represented by land surface temperature (LST), is assumed to resemble air temperature; and water availability, related to precipitation, is represented by the normalized difference vegetation index (NDVI). It is hypothesized that positive correlations between LST and NDVI indicate energy-limited conditions, while negative correlations indicate water-limited conditions. The current project aimed to quantify the spatial and seasonal (spring and summer) distributions of LST-NDVI relations over Europe, using long-term (2000Europe, using long-term ( -2017 MODIS images. Overlaying the LST-NDVI relations on the European biome map revealed that relations between LST and NDVI were highly diverse among the various biomes and throughout the entire study period (March-August). During the spring season (March-May), 80% of the European domain, across all biomes, showed the dominance of significant positive relations. However, during the summer season (June-August), most of the biomes-except the northern ones-turned to negative correlation. This study demonstrates that the drought/vegetation/stress spectral indices, based on the prevalent hypothesis of an inverse LST-NDVI correlation, are spatially and temporally dependent. These negative correlations are not valid in regions where energy is the limiting factor (e.g., in the drier regions in the southern and eastern extents of the domain) or during specific periods of the year (e.g., the spring season). Consequently, it is essential to re-examine this assumption and restrict applications of such an approach only to areas and periods in which negative correlations are observed. Predicted climate change will lead to an increase in temperature in the coming decades (i.e., increased LST), as well as a complex pattern of precipitation changes (i.e., changes of NDVI). Thus shifts in plant species locations are expected to cause a redistribution of biomes. IntroductionIn terrestrial ecosystems, vegetation growth-limiting factors (VGLFs) are species-specific values attributed to a cause that constrains the biological response to appropriate environmental conditions [1]. The primary VGLFs are either climatic or terrestrial. The climatic constraints include water, energy, light, relative humidity, wind, and atmospheric elements (e.g., gases). Climatic variables directly and indirectly affect all levels of biodiversity, from the individual species through to population, community, ecosystem, and up to biome scales [2]. Terrestrial VGLFs include soil characteristics (e.g., texture, depth, and nutrients) and terrain properties (e.g., elevation, slope, and aspect). Different VGLFs should be in balance in order to allow optimal growth and development. When one or more of these factors exceed a low o...

Agricultural Drought Detection with MODIS Based Vegetation Health Indices in Southeast Germany

“…Because evapotranspiration cools the earth's surface, rising surface temperatures may be linked to decreasing water content or a soil moisture deficit and thus water stress in the vegetation canopy [52,53]. If both variables are well correlated, the limiting factor for vegetation growth can be determined depending on the season and location: The NDVI-LST correlation is negative if water is the limiting factor, but it is positive if energy is the limiting factor [36,54,55].…”

“…Finally, approaches also exist within this topic to determine areas and time periods where water is the primary limiting factor for plant growth. In Europe, a correlation analysis between LST and NDVI has revealed that energy was a limiting factor mainly in northern Europe, at high altitudes, and in spring, while water limited plant growth mainly in southern Europe and in summer [36].…”

Seasonal ecosystem vulnerability to climatic anomalies in the Mediterranean

“…Energy-limited regimes merge gradually into water-limited regimes from Scandinavia southwards to the Mediterranean in Europe (Teuling et al, 2009). Karnieli et al (2019) investigated the relationship of the NDVI and land surface temperature at European scale, hypothesizing that a positive relationship indicates an energy-limited condition and a negative one a waterlimited condition. Our results are mostly in agreement with the findings of their study that temperature and the NDVI are comprehensively negatively related in summer in Mediterranean Europe, whereas in spring this is only the case at the southernmost regions of Mediterranean Europe, while in other areas either neutral or negative relationships prevail.…”

Pemetaan Kondisi Ekologi Perkotaan Skala Mikro Menggunakan Citra Landsat 8 di Kota Semarang

“…Nilai NDVI dan SPL dianalisis sebelum mengkaji sebaran nilai UTFVI karena beberapa alasan. Pertama, NDVI menggambarkan distribusi spasial tutupan vegetasi di daerah penelitian dan secara statistik berkorelasi dengan SPL (Karnieli et al, 2019). Kedua, SPL merupakan nilai yang mendasari sebaran UTFVI di lokasi tertentu.…”

“…Namun demikian, jika nilai NDVI jauh di bawah nol maka cenderungnya akan merepresentasikan tubuh air (Jensen, 2015). Pada dasarnya, nilai SPL memiliki hubungan berbanding terbalik dengan nilai NDVI yang berarti bahwa semakin tinggi nilai SPL maka akan semakin rendah nilai NDVI (Karnieli et al, 2019) Namun, hal tersebut tidak sepenuhnya berlaku, terutama untuk objek tubuh air. Pada objek tubuh air, nilai NDVI-nya akan cenderung sangat rendah tetapi nilai SPL-nya akan cenderung rendah.…”