Decline Of Vegetation Research Articles

Mapping salt marsh dieback and condition in South Carolina’s North Inlet-Winyah Bay National Estuarine Research Reserve using remote sensing

Marsh dieback, or brown marsh, occurs when areas of salt marsh vegetation either thin or completely die. The exact extent and locations of marsh dieback are often unknown due to the difficulty accessing salt marshes for in-field observations. Remote sensing provides a synoptic view of earth surfaces and helps to highlight vegetation thinning or loss covering large spatial areas. In 2002–2003 there was a marsh dieback event that affected South Carolina. While most research focused on causes of the event, its extent has not been mapped. Using satellite data to extract the normalized difference vegetation index (NDVI) for years between 1999 and 2003, this study calculated the change in vegetation greenness of the North Inlet salt marsh in Georgetown, South Carolina. Results showed where the marsh vegetation increased or was lost/thinned. The northern section of the marsh experienced the most vegetation decline, while the southern end of the mash experienced a gain in vegetation. The region with the least amount of vegetation decline occurred within mid elevations of the marsh. It is likely that the vegetation within higher elevations experienced stress due to hypersalinity, while vegetation within the lower marsh experienced stress from hypoxia leading to increased rates of vegetation decline in these zones. The elevation of marshes in the northern section is low, and a significant decline in NDVI there may signal a decline in marsh health due to rising sea level.

Sensitivity of Potential Evapotranspiration to Climate and Vegetation in a Water-Limited Basin at the Northern Edge of Tibetan Plateau

Potential evapotranspiration (PET) is important for both hydrological studies and water resources management, especially in arid regions. To better understand how PET varies due to the changing environment, analysis of the sensitivity of PET to climate and underlying surface characteristics is an important necessity. Based on gridded multi-source data sets, the present study estimated PET by using the Shuttleworth-Wallace model from 2000 to 2010 in the upstream and midstream areas of the Heihe River basin. Sensitivity coefficient and contribution coefficient of each parameter were calculated by the sensitivity coefficient method to quantitatively detect and compare the effect of changes in vegetation and climate exerted on the variation of PET. Results showed that: (1) PET varied greatly in the study area. Both climate and vegetation exert effects on the variation of PET; (2) PET is most sensitive to relative humidity in the study area. The sensitivity of PET to vegetation was also great and it increased with the decline of vegetation; (3) relative humidity contributed more to the intra-annual variation than other selected parameters. Vegetation indicated by LAI contribute more than net solar radiation. With this study, our understanding of variations of PET and its driving factors could be expanded from meteorological aspects to vegetation or ecological aspects, which is quite important for eco-hydrology and agricultural water resources management.

Holocene vegetation and climate variability between winter and summer rainfall zones of South Africa

To better understand Holocene vegetation and hydrological changes in South Africa, we analyzed pollen and microcharcoal records of two marine sites GeoB8331 and GeoB8323 from the Namaqualand mudbelt offshore the west coast of South Africa covering the last 9900 and 2200 years, respectively. Our data corroborate findings from literature that climate developments apparently contrast between the summer rainfall zone (SRZ) and winter rainfall zone (WRZ) over the last 9900 years, especially during the early and middle Holocene. During the early Holocene (9900–7800 cal. yr BP), a minimum of grass pollen suggests low summer rainfall in the SRZ, and the initial presence of Renosterveld vegetation indicates relatively wet conditions in the WRZ. Toward the middle Holocene (7800–2400 cal. yr BP), a rather moist savanna/grassland rich in grasses suggests higher summer rainfall in the SRZ resulting from increased austral summer insolation and a decline of fynbos vegetation accompanied by an increasing Succulent Karoo vegetation in the WRZ, which possibly suggests a southward shift of the Southern Hemisphere westerlies. During the last 2200 years, a trend toward higher aridity was observed for the SRZ, while the climate in the WRZ remained relatively stable. The ‘Little Ice Age’ (ca. 700–200 cal. yr BP) was rather cool in both rainfall zones and drier in the SRZ while it was wetter in the WRZ.

Upland habitat loss as a threat to Pantanal wetlands.

The fate of Pantanal, one of the world's largest, most pristine and diverse wetlands, stands in the balance. The most recent (2014) and comprehensive land-cover change assessment of the upper Paraguay River Basin (UPRB), comprising both lowlands (Pantanal floodplain) and their surrounding upland savannas (Cerrado plateaus), shows the extent of decline of native vegetation (Fig. 1). Around 80% of the Pantanal floodplain native vegetation remains (Fig. 1), and over 60% of its Cerrado plateaus have been converted into pasture and croplands (SOS-Pantanal et al. 2015). The most worrying aspect is the fast rate of land clearing during the last 30 years (Supporting Information). In fact, the Cerrado is experiencing higher native vegetation conversion rates than Amazon and Atlantic Forest ecosystems in recent years but is still largely unprotected (Overbeck et al. 2015).

Long‐term effects of liming in Norwegian softwater lakes: the rise and fall of bulbous rush (Juncus bulbosus) and decline of isoetid vegetation

Summary Acidification has been recognised as a serious environmental problem in Scandinavia since the 1970s, and liming has been the main strategy to counteract negative effects on biota by improving water quality. We studied the short‐ and long‐term effects of liming on sediment and water quality, as well as macrophyte development, by comparing five limed with five unlimed lakes during the period 1993–2013. In the limed lakes, massive development of bulbous rush (Juncus bulbosus: Juncaceae) occurred during the first 6–9 years after the start of liming (1984–1993). Juncus bulbosus then started to decline around 1999 and eventually reached its original abundance in 2010. In addition, the cover of the original isoetid vegetation declined by around 60% between 1995 and 2010. In contrast, changes in submerged aquatic vegetation in the unlimed lakes were minor. Liming initially stimulated anaerobic breakdown of sediment organic matter with Fe as the electron acceptor. Juncus bulbosus probably benefitted from the higher CO2 fluxes from the sediment to the water layer in combination with a high NH4+ concentration in the limed sediment. However, the organic matter became less reactive over time, thus eventually providing less CO2. Together with the significant increase in water pH over time, this would have led to a decline in C availability in sediment and water, thus discouraging excessive growth of J. bulbosus. This may explain why J. bulbosus thrived only during the first years after liming. The decline of isoetids in limed lakes was probably caused by a combination of uprooting and sediment anoxia. In limed lakes, isoetids developed a shoot : root ratio that was above the threshold known to promote uprooting of these high buoyancy species on organic sediment. In addition, isoetids eventually became covered by algae and dead J. bulbosus, affecting light conditions and suffocating the remaining isoetid vegetation on limed reductive sediments. In the future, renewed excessive growth of J. bulbosus seems unlikely due to the lack of sufficient carbon sources. It remains, however, unclear whether the original isoetids vegetation can recover. We hypothesise that the isoetid Littorella uniflora may eventually recolonise the lake from the shore and improve the oxygen content of limed sediments; this, in turn will facilitate the germination of other plant species, through high radial oxygen loss in combination with asexual reproduction.

비무장지대(DMZ) 인근의 훼손지 유형 분석 및 복원방향

Purpose of this study is to classify damaged lands according to the cause of the damage and their influences based on characteristic of the damaged lands in DeMilitarized Zone(DMZ) area, and utilize this study as a fundamental study for establishment of ecosystem restoration system. Literature review and field survey have been conducted to review the damage status of DMZ area. For field survey, first year and second year have been conducted, in which type of the damage has been reviewed in this study. In the result, types of damage have been classified into 6 categories: 'alteration of initial landform', 'loss of surface layer', 'land pollution', 'alteration of soil chemical property', 'decline of vegetation', and 'invasion of foreign species'. Restoration for each damage type is as following. First, for alteration of initial landform, the land is restored to the original landform prior to the damage and connection to surrounding ecosystem is considered. Second, for loss of surface layer, lost surface layer is restored or further loss is prevented with stabilization. Third, for land pollution, source of the pollution is eradicated or self-circulation with purification of polluted land is encouraged. Fourth, for alteration of soil chemical property, soil is restored of its original property with eradication of the pollution source and improvement of soil. Fifth, for decline of vegetation, current vegetation and anticipated alteration in future are considered and number of wild species is to be increased based on structure and characteristic of nearby vegetation. Sixth, for invasion of foreign species, prevention of dominance by risky species and facilitation ecological stability with ecological management are to be considered. Influence according to the cause of damage has occurred in secondary(indirect) influence or simultaneous occurrence of several damage types. Considering all these aspects, when type of the damage is complex, restoration process for each of former mentioned 6 damage types with solitary influence should be considered in unison.

훼손지 유형에 따른 생태복원 평가방법 개발

It was required to evaluate ecological restorations in a comprehensive way in order to systematically manage conservation areas such as DMZ and national parks in South Korea. In this research we developed a new approach to evaluating ecological restorations with more various indexes than vegetation covering-related indexes. By analyzing damaged areas in the vicinity of DMZ, major damaged types were identified as six classes: landform modification, surface loss, soil pollution, soil physio-chemical modification, vegetation decline and vegetation damaged. From literature review, 39 indexes were selected and were grouped into four divisions: soil property, vegetation growth & structure, habitat property and landscape structure & functions. By conducting a survey with the selected indexes targeting relevant experts, data on relative importance among the divisions and indexes by damaged type were collected. As a result, it was found that the orders and values of weighted values of the divisions were different by damaged type: for example, soil property (0.402), vegetation growth & structure (0.209), habitat property (0.225), landscape structure & function (0.163) for "landform modification"; but soil property (0.171), vegetation growth & structure (0.401), habitat property (0.270), landscape structure & function (0.158) for "vegetation decline". Similarly, evaluation indexes showed different orders and values of relative importance, easiness in field measurement and representativeness for the division by damaged type, and the values were used for calculating importance factor for each index. In the evaluation table, score1 and score2 were made by the importance factors of indexes multiplied by distribution values which present grades and by the weighted values of divisions. In conclusion, while dealing with the damaged type was considered significant for evaluating and managing restorations, further tests on this table with a range of cases were needed to improve its quality.

CO2 leakage-induced vegetation decline is primarily driven by decreased soil O2

To assess the potential risks of carbon capture and storage (CCS), studies have focused on vegetation decline caused by leaking CO2. Excess soil CO2 caused by leakage can affect soil O2 concentrations and soil pH, but how these two factors affect plant development remains poorly understood. This hinders the selection of appropriate species to mitigate potential negative consequences of CCS. Through pot experiments, we simulated CO2 leakage to examine its effects on soil pH and soil O2 concentrations. We subsequently assessed how maize growth responded to these changes in soil pH and O2. Decreased soil O2 concentrations significantly reduced maize biomass, and explained 69% of the biomass variation under CO2 leakage conditions. In contrast, although leaked CO2 changed soil pH significantly (from 7.32 to 6.75), it remained within the optimum soil pH range for maize growth. This suggests that soil O2 concentration, not soil pH, influences plant growth in these conditions. Therefore, in case of potential CO2 leakage risks, hypoxia-tolerant species should be chosen to improve plant survival, growth, and yield.

Land use and land cover (LULC) changes in semi-arid sub-watersheds of Laikipia and Athi River basins, Kenya, as influenced by expanding intensive commercial horticulture

Agriculturally productive watersheds in Kenya are experiencing important land transformations with consequences on environmental resources. Previous work identified spatial pockets of vegetation decline across sub-watersheds with intensive farming. While this is crucial information in delineating impacted regions, it is important to understand the type of occurring changes, spatial patterns and the rate of change. The study focused in the Athi River and Laikipia regions which have intensified commercial horticulture, yet marginalized semi-arid to arid environments. The study quantified land use and land cover changes between 1984 and 2009/2010, identifying areas of change and the average annual rate of change. Landsat (5 TM, MSS and 7 ETM+) multitemporal data were used in classification and change detection analysis. From the results, both regions experienced intense land transformation at varying magnitudes during the 25 years period. Woody grasslands covered vast areas. In Laikipia, the averaged percentage annual rate of land change to settlements/urban use was highest (20.2%). There was a decline in barren area, forest and wooded grasslands (−1.4%, −0.7% and −0.3% respectively). In the Athi River region, the averaged percentage annual rate of changes was in the order of agriculture, water, settlement, bare soils, woody grasslands (37.7%, 17.2%, 8.4%, 3.9, 2.9% respectively) while dark bare soils, and forest cover declined (−3.4% and −3.3% respectively). Observed LULC transformations were largely attributed to socio-economic drivers including increased human migration into agriculturally productive sub-watersheds fueling growth of settlement, increased irrigation farming and therefore increased area under water, and growth of cities and industrial areas.

Cumulative drought and land‐use impacts on perennial vegetation across a North American dryland region

AbstractQuestionThe decline and loss of perennial vegetation in dryland ecosystems due to global change pressures can alter ecosystem properties and initiate land degradation processes. We tracked changes of perennial vegetation using remote sensing to address the question of how prolonged drought and land‐use intensification have affected perennial vegetation cover across a desert region in the early 21st century?LocationMojave Desert, southeastern California, southern Nevada, southwestern Utah and northwestern Arizona, USA.MethodsWe coupled the Moderate‐Resolution Imaging Spectroradiometer Enhanced Vegetation Index (MODIS‐EVI) with ground‐based measurements of perennial vegetation cover taken in about 2000 and about 2010. Using the difference between these years, we determined perennial vegetation changes in the early 21st century and related these shifts to climate, soil and landscape properties, and patterns of land use.ResultsWe found a good fit between MODIS‐EVI and perennial vegetation cover (2000: R2 = 0.83 and 2010: R2 = 0.74). The southwestern, far southeastern and central Mojave Desert had large declines in perennial vegetation cover in the early 21st century, while the northeastern and southeastern portions of the desert had increases. These changes were explained by 10‐yr precipitation anomalies, particularly in the cool season and during extreme dry or wet years. Areas heavily impacted by visitor use or wildfire lost perennial vegetation cover, and vegetation in protected areas increased to a greater degree than in unprotected areas.ConclusionsWe find that we can extrapolate previously documented declines of perennial plant cover to an entire desert, and demonstrate that prolonged water shortages coupled with land‐use intensification create identifiable patterns of vegetation change in dryland regions.

Decline of woody vegetation in a saline landscape in the Groundnut Basin, Senegal

Several studies have documented that vegetation in the Sahel is highly dynamic and is affected by the prevailing climatic conditions, as well as by human use of the areas. However, little is known about vegetation dynamics in the large saline areas bordering the rivers of West Africa. Combining satellite imagery, the perception of local people and botanical information, this study investigated the vegetation dynamics and the drivers of vegetation changes in Fatick Province, Senegal. Satellite images showed a change in vegetation composition, i.e., a loss of tree cover and an increase in shrub cover, herbaceous cover and tans (highly saline areas with sparse vegetation). Although the trend was the same, the three villages had different vegetation histories. A survey of the woody vegetation showed that shrubs and young trees were dominating with relatively few large trees. Local people perceived a general decline of woody plants from 1993 to 2013. Among 60 species mentioned by local people, 90 % were declining and 10 % increasing. Together the three methods documented a decrease in density and diversity of the woody vegetation, mainly influenced by salinity and land use. The large numbers of young trees indicate a potential for regeneration of some, but not all, tree species. As many tree species appreciated by local people were reported to be declining, local communities have experienced a reduction of their natural resources. Based on villagers’ recommendations for improved vegetation management, we discuss possible contributions including reforestation, desalinization and environmental protection for restoration of the vegetation.

Holocene vegetation and climate variability in the winter and summer rainfall zones of South Africa

To better understand Holocene vegetation and hydrological changes in South Africa, we analyzed pollen and microcharcoal records of two marine sites GeoB8331 and GeoB8323 from the Namaqualand mudbelt offshore the west coast of South Africa covering the last 9900 and 2200 years, respectively. Our data corroborate findings from literature that climate developments apparently contrast between the summer rainfall zone (SRZ) and winter rainfall zone (WRZ) over the last 9900 years, especially during the early and middle Holocene. During the early Holocene (9900–7800 cal. yr BP), a minimum of grass pollen suggests low summer rainfall in the SRZ, and the initial presence of Renosterveld vegetation indicates relatively wet conditions in the WRZ. Toward the middle Holocene (7800–2400 cal. yr BP), a rather moist savanna/grassland rich in grasses suggests higher summer rainfall in the SRZ resulting from increased austral summer insolation and a decline of fynbos vegetation accompanied by an increasing Succulent Karoo vegetation in the WRZ, which possibly suggests a southward shift of the Southern Hemisphere westerlies. During the last 2200 years, a trend toward higher aridity was observed for the SRZ, while the climate in the WRZ remained relatively stable. The ‘Little Ice Age’ (ca. 700–200 cal. yr BP) was rather cool in both rainfall zones and drier in the SRZ while it was wetter in the WRZ.

Plant stoichiometric responses to elevated CO2 vary with nitrogen and phosphorus inputs: Evidence from a global-scale meta-analysis.

Rising levels of atmospheric CO2 have been implicated in changes in the nitrogen (N) and phosphorus (P) content of terrestrial vegetation; however, questions remain over the role of C, N and P interactions in driving plant nutrient stoichiometry, particularly whether N and P additions alter vegetation responses to CO2 enrichment singly. Here we use meta-analysis of 46 published studies to investigate the response of plant N and P to elevated CO2 alone and in combination with nutrient (N and P) additions across temperate vs. tropical biomes. Elevated CO2 reduces plant N concentrations more than plant P concentrations in total biomass pools, resulting in a significant decline in vegetation N/P. However, elevated CO2 treatments in combination with N additions increase plant P concentrations, whereas P additions have no statistical effect on plant N concentrations under CO2 enrichment. These results point to compensatory but asymmetrical interactions between N, P and CO2; that changes in N rapidly alter the availability of P, but not the converse, in response to increased CO2. Our finding implies widespread N limitation with increasing atmospheric CO2 concentrations alone. We also suggest that increased anthropogenic N deposition inputs could enhance plant N and P in a progressively CO2-enriched biosphere.

Palaeo plant diversity in subtropical Africa – ecological assessment of a conceptual model of climate–vegetation interaction

Abstract. We critically reassess a conceptual model here, dealing with the potential effect of plant diversity on climate–vegetation feedback, and we provide an improved version adjusted to plant types that prevailed during the African Humid Period (AHP). Our work contributes to the understanding of the timing and abruptness of vegetation decline at the end of the AHP, investigated by various working groups during the past 2 decades using a wide range of model and palaeo-proxy reconstruction approaches. While some studies indicated an abrupt collapse of vegetation at the end of the AHP, others suggested a gradual decline. Claussen et al. (2013) introduced a new aspect in the discussion, proposing that plant diversity in terms of moisture requirements could affect the strength of climate–vegetation feedback. In a conceptual model study, the authors illustrated that high plant diversity could stabilize an ecosystem, whereas a reduction in plant diversity might allow for an abrupt regime shift under gradually changing environmental conditions. In the light of recently published pollen data and the current state of ecological literature, the conceptual model by Claussen et al. (2013) reproduces the main features of different plant types interacting together with climate, but it does not capture the reconstructed diversity of AHP vegetation. Especially tropical gallery forest taxa, indirectly linked to local precipitation, are not appropriately represented. With a new model version adjusted to AHP vegetation, we can simulate a diverse mosaic-like environment as reconstructed from pollen, and we observe a stabilizing effect of high functional diversity on vegetation cover and precipitation. Sensitivity studies with different combinations of plant types highlight the importance of plant composition on system stability, and the stabilizing or destabilizing potential a single plant type may inherit. The model's simplicity limits its application; however, it provides a useful tool to study the roles of real plant types in an ecosystem and their combined climate–vegetation feedback under changing precipitation regimes.

Vegetation response to intensive commercial horticulture and environmental changes within watersheds in central highlands, Kenya, using AVHRR NDVI data

Expansion and heterogeneous clustering of commercial horticulture within the central highlands of Kenya after the mid-1990s impact watersheds and the sustainable resource management. This is distressing since climate conditions for world horticultural regions are projected to change, making such farming extremely difficult and costly to the environment. To understand the scope of impact on vegetation, the study evaluated (1) interannual variability in averaged normalized difference vegetation index (NDVI); (2) trends in average annual NDVI before and after 1990 – the presumed onset of rapid horticulture; and (3) relationship between the average annual NDVI and large-scale commercial farms, population density, and mean annual rainfall in subwatersheds. Time-series analysis of long-term Global Inventory Modeling and Mapping Studies NDVI data were analyzed as indicator of vegetation condition. NDVI trends before 1990s (1982–1989) and after 1990s (1990–2006) were evaluated to determine the slope (sign), and the Spearman’s correlation coefficient (strength). Overall, results show considerable variations in vegetation condition due largely to mixed factors including intensive farming activities, drought, and rainfall variation. Statistical analysis shows significant differences in slopes before 1990 and after 1990 (p < 0.05 and p < 0.1 respectively). Negative (decline) trends were common after 1990, linked to increased commercial horticulture and related anthropogenic disturbances on land cover. There was decline in vegetation over densely populated subwatersheds, though low NDVI values in 1984 and 2000 were the effect of severe droughts. Understanding the linkage between vegetation responses to the effects of human-induced pressure at the subwatershed scale can help natural resource managers approach conservation measures more effectively.

Changes in vegetation persistence across global savanna landscapes, 1982–2010

We present a global analysis of the changing face of vegetation persistence in savanna ecosystems by boreal seasons. We utilized nearly 30 years of monthly normalized difference vegetation index data in an innovative time-series approach and developed associated statistical significance tests, making the application of continuous vegetation metrics both more rigorous and more useful to research. We found that 8,000,000–11,000,000 km2 of savanna have experienced significant vegetation decline during each season, while 20,000,000–23,000,000 km2 have experienced an increase in vegetation persistence during each season, relative to the baseline period (1982–1985). In addition, with the exception of the March–April–May season, which is mixed, the pattern of significant vegetation persistence in the Northern Hemisphere is almost exclusively positive, while it is negative in the Southern Hemisphere. This finding highlights the increasing vulnerability of the Southern Hemisphere savanna landscapes; either resulting from changing precipitation regimes (e.g., southern Africa) or agricultural pressures and conversions (e.g., South America).

Is there an impact of climate change on soil carbon contents in England and Wales?

SummaryIt is not yet clear how soils are responding to a warming climate. A major study using the National Soil Inventory (NSI) of England and Wales reported large declines in soil carbon concentration across 11 land uses between 1978 and 2003 and concluded there was a link to climate change. However, a second, almost contemporary study, recorded no significant changes, raising the possibility that the reported declines were caused by changes in land use and management rather than by climate change. We have used ‘space‐for‐time’ substitution on the data from the initial NSI study, combined with changes in rainfall and temperature over the survey period, to determine the extent to which the declines in soil carbon observed in the second NSI study could be predicted from changes in climate. For organo‐mineral and mineral soils, little (0–5%) of the observed decline in carbon concentration can be predicted from changes in climate. In contrast, 9–22% of the changes reported for organic soils in semi‐natural habitats are consistent with changes in temperature and rainfall between the two NSI surveys. We also found that carbon concentration in organic soils in semi‐natural habitats declines as temperatures exceed 7°C, mirroring independent observations for the decline in bog and dense shrub moor vegetation as temperatures rise above 7°C, and raising the possibility that climate change may influence soil carbon indirectly by changing vegetation cover, and hence litter quality.

NDVI‐indicated long‐term vegetation dynamics in Mongolia and their response to climate change at biome scale

ABSTRACTBased on the vegetation map of Mongolia, Global Inventory Monitoring and Modelling Studies (GIMMS) normalized difference vegetation index (NDVI) (1982–2006), the Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI (2000–2010), and temperature and precipitation data derived from 60 meteorological stations, this study has thoroughly examined vegetation dynamics in Mongolia and their responses to regional climate change at biome scale. To ensure continuity and consistency between the two NDVI datasets, the MODIS NDVI was first calibrated to the GIMMS NDVI based on the overlapping period of 2000–2006. Good calibration results with R2 values of 0.86–0.98 between the two NDVI datasets were obtained and can detect subtle trends in the long‐term vegetation dynamics of Mongolia. The results indicated that for various biomes, although NDVI changes during 1982–2010 showed great variation, vegetation greening for all biomes in Mongolia seem to have stalled or even decreased since 1991–1994, particularly for meadow steppe (0.0015 year−1), typical steppe (−0.0010 year−1), and desert steppe (−0.0008 year−1), which is an apparent turning point (TP) of the vegetation growth trend in Mongolia. A pronounced drying trend (from −4.399 mm year−1 in meadow steppe since 1990 to −2.445 mm year−1 in alpine steppe since 1993) occurred between 1990 and 1994, and persistently warming temperatures (0.015 °C year−1 in alpine steppe to 0.070 °C year−1 in forest and meadow steppe) until recently have likely played a major role in this NDVI trend reversal. However, the NDVI TP varied by biome, month, and climate and was not coupled exactly with climatic variables. The impact on climate of both same‐time and lagged‐time temperature and precipitation effects also varied strongly across biomes and months. On the whole, climate‐related vegetation decline and associated potential desertification trends will likely be among the major sources of ecological pressure for each biome in Mongolia, which could intensify environmental problems like sandstorms in other East Asian regions.

Monitoring vegetation dynamics with medium resolution MODIS-EVI time series at sub-regional scale in southern Africa

Currently there is a lack of knowledge on spatio-temporal patterns of land surface dynamics at medium spatial scale in southern Africa, even though this information is essential for better understanding of ecosystem response to climatic variability and human-induced land transformations. In this study, we analysed vegetation dynamics across a large area in southern Africa using the 14-years (2000–2013) of medium spatial resolution (250m) MODIS-EVI time-series data. Specifically, we investigated temporal changes in the time series of key phenometrics including overall greenness, peak and timing of annual greenness over the monitoring period and study region. In order to specifically capture spatial and per pixel vegetation changes over time, we calculated trends in these phenometrics using a robust trend analysis method. The results showed that interannual vegetation dynamics followed precipitation patterns with clearly differentiated seasonality. The earliest peak greenness during 2000–2013 occurred at the end of January in the year 2000 and the latest peak greenness was observed at the mid of March in 2012. Specifically spatial patterns of long-term vegetation trends allowed mapping areas of (i) decrease or increase in overall greenness, (ii) decrease or increase of peak greenness, and (iii) shifts in timing of occurrence of peak greenness over the 14-year monitoring period. The observed vegetation decline in the study area was mainly attributed to human-induced factors. The obtained information is useful to guide selection of field sites for detailed vegetation studies and land rehabilitation interventions and serve as an input for a range of land surface models.

The applicability of DNA barcoding for dietary analysis of sika deer

AbstractIn Japan, overgrazing by sika deer (Cervus nippon) has been suggested to cause a decline in forest understory vegetation. DNA barcoding has become an accepted method for analyzing the diets of animals and may be useful for evaluating the impact of sika deer on vegetation. However, the applicability of DNA barcoding in the dietary analysis of sika deer, particularly whether all of the food plants can be detected with sufficient taxonomic resolution and whether the results can be evaluated quantitatively, has not been investigated. We conducted a feeding trial by feeding five plant species to a captive sika deer and sequenced the chloroplast trnL P6 loop region from the sika deer’s fecal DNA using the Ion PGM sequencer. We detected the sequences of all of the food plants at the species level using the local (selfproduced) database and at the genus or family level with the global database. Although the sequences of some major food plants were detected with high frequency, the proportion of consumed food plants did not match the proportion of sequences obtained from fecal DNA. With further technical advances and the further completeness of the sequence database for vegetation, DNA barcoding will be a useful tool for the dietary study of sika deer.