Stephen S. Young

Land-cover change analysis of China using global-scale Pathfinder AVHRR Landcover (PAL) data, 1982?92

This paper reviews the application of NOAA/NASA Pathfinder AVHRR Land (PAL) dataset (8 km) to detect land-cover change in China between 1982 and 1992. Changes in productivity, as indicated by a normalized difference vegetation index (NDVI), not changes in land-cover classifications are analysed. The research uses the change detection techniques of simple differencing, or univariate differencing, and standardised principal component analysis. Both techniques produce similar results which indicate that forest regions are decreasing in productivity while agricultural regions are increasing. The majority of pixels indicating changes are ones showing an increase in productivity and are clustered primarily in agricultural regions, especially the North China Plain, along with grasslands. The paper demonstrates the potential of using global-scale PAL data to monitor land-cover change in areas where official governmental data are either suspect or hard to acquire. China is an important area in which to analyse landcover change because little is known about recent changes and the region has a strong potential impact on global environmental change.

Persistent changes in NDVI between 1982 and 2003 over India using AVHRR GIMMS (Global Inventory Modeling and Mapping Studies) data

The preliminary results of Normalized Difference Vegetation Index (NDVI) change studies over India using data from Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies (AVHRR GIMMS) between 1982 and 2003 are presented. The three methodologies of univariate differencing, temporal profiling and anomaly analysis were undertaken. Univariate differencing was used to determine overall NDVI change between 1982 and 2003. A persistence filter was used to filter out ephemeral changes. The temporal profile analyses were carried out over different meteorological subdivisions to compare changes in NDVI with rainfall patterns. In the anomaly analysis, the areas of change were analysed over different land cover categories derived from IRS‐WiFS data. The preliminary results indicate that positive trends in vegetation change occurred over most parts of the country and these changes appear not to be highly correlated with rainfall data, indicating that land cover transformations may be the major driving force behind the changes. The land cover classifications experiencing the greatest increasing NDVI were tropical thorn forests and intensive agriculture and the land cover experiencing very slow growth included current jhum, tropical moist deciduous and temperate evergreen forest. Five‐year moving averages indicate a general increase in NDVI from 1986 to 1998 and then declining thereafter. This is a concern in most of the meteorological subdivisions.

Effectiveness of China’s National Forest Protection Program and Nature Reserves

There is profound interest in knowing the degree to which Chinas institutions are capable of protecting its natural forests and biodiversity in the face of economic and political change. Chinas 2 most important forest-protection policies are its National Forest Protection Program (NFPP) and its national-level nature reserves (NNRs). The NFPP was implemented in 2000 in response to deforestation-caused flooding. We undertook the first national, quantitative assessment of the NFPP and NNRs to examine whether the NFPP achieved its deforestation-reduction target and whether the NNRs deter deforestation altogether. We used MODIS data to estimate forest cover and loss across mainland China (2000-2010). We also assembled the first-ever polygon dataset for Chinas forested NNRs (n = 237, 74,030 km(2) in 2000) and used both conventional and covariate-matching approaches to compare deforestation rates inside and outside NNRs (2000-2010). In 2000, 1.765 million km(2) or 18.7% of mainland China was forested (12.3% with canopy cover of ≥70%)) or woodland (6.4% with canopy cover <70% and tree plus shrub cover ≥40%). By 2010, 480,203 km(2) of forest and woodland had been lost, an annual deforestation rate of 2.7%. Forest-only loss was 127,473 km(2) (1.05% annually). In the NFPP provinces, the forest-only loss rate was 0.62%, which was 3.3 times lower than in the non-NFPP provinces. Moreover, the Landsat data suggest that these loss rates are overestimates due to large MODIS pixel size. Thus, China appears to have achieved, and even exceeded, its target of reducing deforestation to 1.1% annually in the NFPP provinces. About two-thirds of Chinas NNRs were effective in protecting forest cover (prevented loss 4073 km(2) unmatched approach; 3148 km(2) matched approach), and within-NNR deforestation rates were higher in provinces with higher overall deforestation. Our results indicate that Chinas existing institutions can protect domestic forest cover.

Changing patterns of global‐scale vegetation photosynthesis, 1982–1999

The primary objective of this research was to assess changes in global vegetation photosynthesis between 1982 and 1999. Global‐scale Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) data from the Pathfinder AVHRR Land (PAL) and Global Inventory Modeling and Mapping Studies (GIMMS) datasets were analysed for 96% of the non‐Antarctic land area of the Earth. The results showed that between 1982 and 1999 over 30% of the Earths land surface increased and less than 5% decreased in annual average photosynthesis greater than 4%. Although both the PAL and GIMMS datasets produced broadly similar patterns of change, there were distinct differences between the two datasets. Changes in vegetation photosynthesis were occurring in spatial clusters across the globe and were being driven by climate change, El Niño–Southern Oscillation (ENSO) events and human activity.

Differences in bird diversity between two swidden agricultural sites in mountainous terrain, Xishuangbanna, Yunnan, China

Abstract This study took a comparative look at the relationship between human-altered landscapes and bird diversity in two mountainous swidden (slash and burn) agricultural sites in Xishuangbanna, Yunnan, China. Over the course of 3 years (1998–2000) the authors used line-transect identification surveys in the two regions, Mengsong and Jinuo, where four different habitats were surveyed: 6-year fallow fields; traditional economic forests; monsoon evergreen broadleaf forests; and montane rain forests. Data were analyzed for species diversity, richness (family, genera, species), co-occurrence (family, genera, species), characterization of migratory status and feeding habits. Both of these study areas are inhabited by minority groups (Hani and Jinuo) that employ swidden agriculture as their main form of economic activity. The forest landscape in the Jinuo ethnic region is quickly transforming due to changing agricultural practices, and as a result bird diversity and richness are declining, while the Hani ethnic region (Mengsong), with a stable form of traditional swidden agriculture, is maintaining a high diversity and richness of birds. The greatest differences in bird diversity between the two sites occurred in the traditional economic forests and the 6-year fallow fields where the Hani region had a much greater richness and diversity. The two natural forest types (monsoon evergreen broadleaf forests and montane rain forests) were more similar in richness and diversity and also maintained the greatest richness and diversity of the four forest types analyzed. The transformation of healthy forests into degraded landscapes is one of the major impacts of human activity on the natural environment, which is posing a great threat to biodiversity. This study looks at the bird diversity of the two regions and tries to take into account how humans can extract economic benefits while preserving ecological benefits, such as a landscape that allows biodiversity to thrive.

A STUDY OF THE STRUCTURE AND COMPOSITION OF AN OLD GROWTH AND SECONDARY BROAD-LEAVED FOREST IN THE AILAO MOUNTAINS OF YUNNAN, CHINA

A cooperative U.S.A.-China ecological study took place at the Xujiaba Nature Sanctuary on the northern crest of the Ailao Shan (mountains) in central-west Yunnan. By making forest access difficult and keeping human immigration low, the mountainous topography of Yunnan has assisted in protecting forest cover. This project studied the vegetational and bird structure and composition of an old growth and a secondary evergreen broad-leaved forest. The study found that the old growth had better developed layers, canopy stems were wider and taller, and there was a greater diversity of bird species. The secondary forest had a higher stem density in the canopy, more even-aged stems in the canopy, more coppiced stems in the canopy, and a greater canopy and overall basal area. Both forest types maintained a high diversity of woody species, but different species were dominant in each forest type and in the canopy and subcanopy of the forests. Natural forests are rare in China and are dwindling quickly. Most natural forest is found in frontier regions and it is here where research and management efforts are needed most urgently. In the nature reserves more ecological research, conservation education, and greater efforts to understand local demands, use, and knowledge about the forests are needed.

Bird distribution and conservation in the Ailao Mountains, Yunnan, China

Results from a long-term ecological study carried out by Chinese and American researchers in the Xujiaba Ecological Reserve within the Ailao Shan Nature Reserve show the importance of the Ailao Mountains as a sanctuary for numerous bird species. Natural forest cover is decreasing throughout Southwestern China and adjacent Southeast Asia leading to a diminished habitat for plants and animals throughout the region. Remnant primary and secondary forests in the Ailao Mountains supply habitat for an abundance of bird species and other wildlife, many facing possible extinction. This study analyzes the bird diversity of three different ecosystems: primary broad-leaved evergreen forest on the crest of the Ailao Mountains, and two secondary pine forests, regenerating from clear-cut evergreen broad-leaved forest, on the eastern and western slopes. The primary forest (30 ha plot) has the greatest diversity of bird species with 169 species in the summer and 107 in the winter compared to 98 and 75, respectively, for the western slopes (40 ha plot) and 72 and 49, respectively, for the eastern slopes (40 ha plot). The research found a large local seasonal migration between the crest of the mountain range and the slopes as well as increasing numbers of long-distance migrants. The research also notes that the variety of ecosystems supports a large variety of bird species including 218 within the Ecological Reserve and 365 in the greater Northern Ailao Mountains. Conservation efforts in the Reserve focus not only on resident birds, but also on migratory birds. Because of a seasonal local migration, forest ecosystems outside of the Reserve need preservation as well as forests inside of the Reserve. To accomplish effective conservation, a combination of ecological research, conservation education and local economic development must be incorporated.

Estimating bidirectional angles in NOAA AVHRR images

In studies concerning the surface bidirectional reflectance distribution function (BRDF) and thermal-infrared multiangular emissions, Sun-sensor geometry must be known. This Letter provides a potential and simple method for NOAA Advanced Very High Resolution Radiometer (AVHRR) users to estimate the imaging configuration of each pixel in a geometrically corrected image. Our formulas were tested with example AVHRR data and their precision was shown to be comparatively high with a maximum error of either the satellite zenith or azimuth angle less than 4°. The standard deviation for the zenith is 2.07° and azimuth is 2.47°.

The Effectiveness of Chinas National Forest Protection Program and National-level Nature Reserves, 2000 to 2010

There is profound interest in knowing the degree to which China’s institutions are capable of protecting its natural forests and biodiversity in the face of economic and political change. China’s two most important forest protection policies are its National Forest Protection Program (NFPP) and its National-level Nature Reserves (NNRs). The NFPP was implemented in 17 provinces starting in the year 2000 in response to deforestation-caused flooding. We used MODIS data (MOD13Q1) to estimate forest cover and forest loss across mainland China, and we report that 1.765 million km2 or 18.7% of mainland China was covered in forest (12.3%, canopy cover > 70%) and woodland (6.4%, 40% ≤ canopy cover < 70%) in 2000. By 2010, a total of 480,203 km2 of forest + woodland was lost, amounting to an annual deforestation rate of 2.7%. The forest-only loss was 127,473 km2, or 1.05% annually. The three most rapidly deforested provinces were outside NFPP jurisdiction, in the southeast. Within the NFPP provinces, the annual forest + woodland loss rate was 2.26%, and the forest-only rate was 0.62%. Because these loss rates are likely overestimates, China appears to have achieved, and even exceeded, its NFPP target of reducing deforestation to 1.1% annually in the target provinces. We also assemble the first-ever polygon dataset for China’s forested NNRs (n = 237), which covered 74,030 km2 in 2000. Conventional unmatched and covariate-matching analyses both find that about two-thirds of China’s NNRs exhibit effectiveness in protecting forest cover and that within-NNR deforestation rates are higher in provinces that have higher overall deforestation.

SATELLITE DETECTED BROAD-SCALE VEGETATION CHANGE IN CHINA, 1982–1999

Abstract This paper analyzes vegetation change throughout China between 1982 and 1999 using global scale AVHRR satellite data. It analyzes changes in NDVI and links these changes to associated land covers. Two time series (1982 to 1993 and 1995 to 1999) were analyzed using Principal Components Analysis, Simple Differencing, and Temporal Profiling. In both periods more areas increased in NDVI than decreased, with some grasslands and croplands continually increasing. Fewer areas decreased in NDVI with forest areas decreasing the most. The North China Plain region experienced strong NDVI increases in the 1980s and then strong decreases in the late 1990s.