scholarly journals Greater loss and fragmentation of savannas than forests over the last three decades in Yunnan Province, China

2021 ◽  
Author(s):  
R. Sedricke Lapuz ◽  
Angelica Kristina Jaojoco ◽  
Sheryl Rose Cay Reyes ◽  
Jose Don Tungol De Alban ◽  
Kyle W. Tomlinson
Keyword(s):  
Yunnan Province ◽  
Vegetation Change ◽  
Forest Cover ◽  
Vegetation Type ◽  
Landsat Imagery ◽  
Woody Encroachment ◽  
Mean Annual Temperature ◽  
Dry Valleys ◽  
Stable States ◽  
Fire Policy

Abstract Yunnan Province, southwest China, has a monsoonal climate suitable for a mix of fire-driven savannas and fire-averse forests as alternate stable states, and has vast areas with savanna physiognomy. Presently, savannas are only formally recognised in the dry valleys of the region, and a no-fire policy has been enforced nationwide since the 1980s. Misidentification of savannas as forests may have contributed to their low protection level and fire-suppression may be contributing to vegetation change towards forest states through woody encroachment. Here, we present an analysis of vegetation and land-use change in Yunnan for years 1986, 1996, 2006, and 2016 by classifying Landsat imagery using a hybrid of unsupervised and supervised classification. We assessed how much savanna area had changed over the three decades (area loss, fragmentation), and of this how much was due to direct human intervention versus vegetation transition. We also assessed how climate (mean annual temperature, aridity), landscape accessibility (slope, distance to roads), and fire had altered transition rates. Our classification yielded accuracy values of 77.89%, 82.16%, 94.93%, and 86.84% for our four maps, respectively. In 1986, savannas had the greatest area of any vegetation type in Yunnan at 40.30%, whereas forest cover was 30.78%. Savanna coverage declined across the decades mainly due to a drop in open parkland savannas, while forest cover remained stable. Savannas experienced greater fragmentation than forests. Savannas suffered direct loss of coverage to human uses and to woody encroachment. Savannas in more humid environments switched to denser vegetation at a higher rate. Fire slowed the rate of conversion away from savanna states and promoted conversion towards them. We identified remaining savannas in Yunnan that can be considered when drafting future protected areas. Our results can inform more inclusive policy-making that considers Yunnan’s forests and savannas as distinct vegetation types with different management needs.

Assessing the response of vegetation change to drought during 2009–2018 in Yunnan Province, China

2021 ◽  
Author(s):  
Yuanhe Yu ◽  
Yuzhen Shen ◽  
Jinliang Wang ◽  
Yuchun Wei ◽  
Lanping Nong ◽  
...  
Keyword(s):  
Yunnan Province ◽  
Vegetation Change

Catastrophic disturbance in the presettlement forests of the Upper Peninsula of Michigan

1999 ◽  
Vol 29 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Quanfa Zhang ◽  
Kurt S Pregitzer ◽  
David D Reed
Keyword(s):  
Forest Cover ◽  
Vegetation Type ◽  
Natural Disturbance ◽  
Growth Stages ◽  
Mosaic Landscape ◽  
Upper Peninsula ◽  
Rotation Periods ◽  
General Land Office ◽  
Ecological Unit ◽  
Upper Peninsula Of Michigan

The General Land Office (GLO) survey notes (1840-1856) were used to examine the interaction among natural disturbance, vegetation type, and topography in the presettlement forests of the Luce District, an ecological unit of approximately 902 000 ha in the Upper Peninsula of Michigan, U.S.A. The surveyors recorded 104 fire and 126 windthrow incidences covering 3.1 and 2.8% of the total length of the surveyed lines, respectively. The rotation periods over the entire landscape were 480 years for fire and 541 years for windthrow, but these varied with vegetation type and topographic position. Fire occurred more frequently on southerly aspects and at elevations where pinelands were concentrated. The density of windthrow events increased with elevation and slope, with the highest occurrence on westerly aspects. Based on the estimated rotation periods, we calculated that 7.5, 24.4, and 68.1% of the presettlement forest were in the stand initiation, stem exclusion, and old forest (including both understory reinitiation and old growth) stages, respectively. Pinelands and mixed conifers were the major components in both the stand initiation (34.5 and 31.1%) and the stem exclusion stage (20.9 and 39.8%), while mixed conifers (39.3%) and northern hardwoods (34.7%) were the major old-forest cover types. The diverse mosaic of various successional stages generated by natural disturbance suggests a "shifting-mosaic" landscape in this region.

Hydrological implications of vegetation change in a subarctic, alpine catchment, Yukon Territory, Canada 

2021 ◽  
Author(s):  
Erin Nicholls ◽  
Gordon Drewitt ◽  
Sean Carey
Keyword(s):  
Soil Moisture ◽  
Interannual Variability ◽  
Sap Flow ◽  
Vegetation Change ◽  
Vegetation Type ◽  
Growing Season ◽  
White Spruce ◽  
Yukon Territory ◽  
Precipitation Regimes ◽  
Tall Shrub

<p>As a result of altitude and latitude amplified impacts of climate change, widespread alterations in vegetation composition, density and distribution are widely observed across the circumpolar north. The influence of this vegetation change on the timing and magnitude of hydrological fluxes is uncertain, and is confounded by changes driven by increased temperatures and altered precipitation (P) regimes. In northern alpine catchments, quantification of total evapotranspiration (ET) and evaporative partitioning across a range of elevation-based ecosystems is critical for predicting water yield under change, yet remains challenging due to coupled environmental and phenological controls on transpiration (T). In this work, we analyze 6 years of surface energy balance, ET, and sap flow data at three sites along an elevational gradient in a subarctic, alpine catchment near Whitehorse, Yukon Territory, Canada. These sites provide a space-for-time evaluation of vegetation shifts and include: 1) a low-elevation boreal white spruce forest (~20 m), 2) a mid-elevation subalpine taiga comprised of tall willow (Salix) and birch (Betula) shrubs (~1-3 m) and 3) a high-elevation subalpine taiga with shorter shrub cover (< 0.75 m) and moss, lichen, and bare rock. Specific objectives are to 1) evaluate interannual ET dynamics within and among sites under different precipitation regimes , and 2) assess the influence of vegetation type and structure, phenology, soil and meteorological controls on ET dynamics and partitioning.  Eddy covariance and sap flow sensors operated year-round at the forest and during the growing season at the mid-elevation site on both willow and birch shrubs for two years. Growing season ET decreased and interannual variability increased with elevation, with June to August ET totals of 250 (±3) mm at Forest, 192 (±9) mm at the tall shrub site, and 180 (± 26) mm at the short shrub site. Comparatively, AET:P ratios were the highest and most variable at the forest (2.4 ± 0.3) and similar at the tall and short shrub (1.2 ± 0.1).  At the forest, net radiation was the primary control on ET, and 55% was direct T from white spruce. At the shrub sites, monthly ET rates were similar except during the peak growing season when T at the tall shrub site comprised 89% of ET, resulting in greater total water loss. Soil moisture strongly influenced T at the forest, suggesting the potential for moisture stress, yet not at the shrub sites where there was no moisture limitation. Results indicate that elevation advances in treeline will increase overall ET and lower interannual variability; yet the large water deficit during summer implies a strong reliance on early spring snowmelt recharge to sustain soil moisture. Changes in shrub height and density will increase ET primarily during the mid-growing season. This work supports the assertion that predicted changes in vegetation type and structure will have a considerable impact on water partitioning in northern regions, and will also vary in a multifaceted way in response to changing temperature and P regimes.  </p>

scholarly journals Vegetation Indices Do Not Capture Forest Cover Variation in Upland Siberian Larch Forests

2018 ◽  
Vol 10 (11) ◽  
pp. 1686 ◽  
Author(s):  
Michael Loranty ◽  
Sergey Davydov ◽  
Heather Kropp ◽  
Heather Alexander ◽  
Michelle Mack ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Forest Cover ◽  
Global Climate ◽  
Vegetation Indices ◽  
Temporal Trends ◽  
Siberian Larch ◽  
Field Observations ◽  
Larch Forests

Boreal forests are changing in response to climate, with potentially important feedbacks to regional and global climate through altered carbon cycle and albedo dynamics. These feedback processes will be affected by vegetation changes, and feedback strengths will largely rely on the spatial extent and timing of vegetation change. Satellite remote sensing is widely used to monitor vegetation dynamics, and vegetation indices (VIs) are frequently used to characterize spatial and temporal trends in vegetation productivity. In this study we combine field observations of larch forest cover across a 25 km2 upland landscape in northeastern Siberia with high-resolution satellite observations to determine how the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) are related to forest cover. Across 46 forest stands ranging from 0% to 90% larch canopy cover, we find either no change, or declines in NDVI and EVI derived from PlanetScope CubeSat and Landsat data with increasing forest cover. In conjunction with field observations of NDVI, these results indicate that understory vegetation likely exerts a strong influence on vegetation indices in these ecosystems. This suggests that positive decadal trends in NDVI in Siberian larch forests may correspond primarily to increases in understory productivity, or even to declines in forest cover. Consequently, positive NDVI trends may be associated with declines in terrestrial carbon storage and increases in albedo, rather than increases in carbon storage and decreases in albedo that are commonly assumed. Moreover, it is also likely that important ecological changes such as large changes in forest density or variable forest regrowth after fire are not captured by long-term NDVI trends.

Movement of small mammals across divided highways with vegetated medians

2011 ◽  
Vol 89 (12) ◽  
pp. 1214-1222 ◽  
Author(s):  
Ashley A.D. McLaren ◽  
Lenore Fahrig ◽  
Nigel Waltho
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Vegetation Cover ◽  
Forest Cover ◽  
Vegetation Type ◽  
Barrier Effect ◽  
Cover Type ◽  
Study Sites ◽  
Median Width ◽  
Initial Capture

Previous studies suggest the gap in forest cover generated by roads contributes to the barrier effect of roads on movement of forest-dwelling small mammals. However, it is not known if vegetated medians of divided highways affect movement of small mammals by reducing the effective highway width. The purpose of our study was to determine whether the type of vegetation cover in the median (treed or grassy) or median width affects small-mammal crossings of divided highways. At 11 study sites varying in median cover type and width, we live-trapped small mammals next to one side of the highway and translocated them to the opposite side of the highway using a standardized translocation distance. In total, 24% of translocated individuals were recaptured on the side of the highway of initial capture, i.e., they had moved across the entire highway. This was significantly lower than what would have been expected in the absence of the highway (58%). The overall probability of recapturing a translocated individual was not significantly related to median cover type or width. Our results suggest that efforts to mitigate the barrier effect of highways on small mammals cannot be accomplished by altering median vegetation type and width.

scholarly journals Forest areas remote monitoring within the limits of transport objects impact

2021 ◽  
pp. 109-118
Author(s):  
Dmytro Liashenko ◽  
◽  
Dmytro Pavliuk ◽  
Vadym Belenok ◽  
Vitalii Babii ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Spatial Data ◽  
Remote Monitoring ◽  
Forest Cover ◽  
Landsat Imagery ◽  
Remote Sensing Data ◽  
Transport Infrastructure ◽  
Nature Management ◽  
Collecting Methods ◽  
Remote Sensing Methods

The article studies the issues of using remote sensing data for the tasks of ensuring sustainable nature management in the territories within the influence of transport infrastructure objects. Peculiarities of remote monitoring for tasks of transport networks design and in the process of their operation are determined. The paper analyzes the development of modern remote sensing methods (satellite imagery, the use of mobile sensors installed on cars or aircraft). A brief overview of spatial data collecting methods for the tasks of managing the development of territories within the influence of transport infrastructure (roads, railways, etc.) has made. The article considers the experience of using remote sensing technologies to monitor changes in the parameters of forest cover in the Transcarpathian region (Ukraine) in areas near to highways, by use Landsat imagery.

scholarly journals A Land Cover Changes Model Based on Carbon Stock in the Mount Patah Region of, Bengkulu-Indonesia

2020 ◽  
Vol 4 (9) ◽  
pp. 1-5
Keyword(s):  
Land Use ◽  
Information System ◽  
Land Cover ◽  
Forest Inventory ◽  
Carbon Stock ◽  
Forest Cover ◽  
Landsat Imagery ◽  
Land Cover Changes ◽  
Land Area ◽  
Reduced Data

Forest cover in Bengkulu is reduced. Data from WARSI shows, 1990 forest cover areas in the province are approximately 1,009,209 hectares or 50.4 % of the land area reaching 1,979,515 hectares. But now, it is only 685,762 hectares of the area of his blood. That is, the period of 25 years, there is a forest cover decline of 323,447 hectares. Forest and land cover changes are the largest contributor to greenhouse gas emissions. The purpose of this article is to see land cover changes based on carbon stock in the years 2009 and 2018. Model of land cover change based on carbon stock year 2028 and 2038. The method of this research uses the calculation of the Stock Difference Approach with spatial analysis of national land closure of Landsat imagery 2009-2018 and biomass data for forest inventory results Geographic Information System (GIS). The results of this research were the reduced forest area and the change in land use changed from 2009 and 2018. So carbon stock is also increasingly reduced.

scholarly journals MODELING PRECIPITATION DEPENDENT FOREST RESILIENCE IN INDIA

2018 ◽  
Vol XLII-3 ◽  
pp. 263-266 ◽  
Author(s):  
P. Das ◽  
M. D. Behera ◽  
P. S. Roy
Keyword(s):  
Forest Cover ◽  
Vegetation Type ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
High Tendency ◽  
North East India ◽  
North East ◽  
Forest Resilience ◽  
The Impact

The impact of long term climate change that imparts stress on forest could be perceived by studying the regime shift of forest ecosystem. With the change of significant precipitation, forest may go through density change around globe at different spatial and temporal scale. The 100 class high resolution (60 meter spatial resolution) Indian vegetation type map was used in this study recoded into four broad categories depending on phrenology as (i) forest, (ii) scrubland, (iii) grassland and (iv) treeless area. The percentage occupancy of forest, scrub, grass and treeless were observed as 19.9&amp;thinsp;%, 5.05&amp;thinsp;%, 1.89&amp;thinsp;% and 7.79&amp;thinsp;% respectively. Rest of the 65.37&amp;thinsp;% land area was occupied by the cropland, built-up, water body and snow covers. The majority forest cover were appended into a 5&amp;thinsp;km&amp;thinsp;&amp;times;&amp;thinsp;5&amp;thinsp;km grid, along with the mean annual precipitation taken from Bioclim data. The binary presence and absence of different vegetation categories in relates to the annual precipitation was analyzed to calculate their resilience expressed in probability values ranging from 0 to 1. Forest cover observed having resilience probability (Pr) &amp;lt;&amp;thinsp;0.3 in only 0.3&amp;thinsp;% (200&amp;thinsp;km<sup>2</sup>) of total forest cover in India, which was 4.3&amp;thinsp;% &amp;lt;&amp;thinsp;0.5&amp;thinsp;Pr. Majority of the scrubs and grass (64.92&amp;thinsp;% Pr&amp;thinsp;&amp;lt;&amp;thinsp;0.5) from North East India which were the shifting cultivation lands showing low resilience, having their high tendency to be transform to forest. These results have spatial explicitness to highlight the resilient and non-resilient distribution of forest, scrub and grass, and treeless areas in India.

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