Sustainable Rubber Abstract

  1. Rubber and LCLUC in Mainland Southeast Asia
  2. Do rubber plantations threaten soil biodiversity? The case of Rubber plantations in Thailand
  3. Obtaining rubber plantation age information from very dense Landsat TM & ETM+ time series data
  4. Linking Landsat 8 spectral reflectance and floristic pattern of Xishuangbanna’s tropical rain forests
  5. An analysis of land-use change and its driving factors in the Naban River Watershed
  6. The pattern and dynamics of rubber monoculture expansion in Xishuangbanna, SW China
  7. Combining sacred natural sites to develop an effective conservation system in Xishuangbanna
  8. Effects of landscape configuration on wild bee diversity in a rubber-dominated landscape of southern Yunnan (China)

Rubber and LCLUC in Mainland Southeast Asia

by Jefferson Fox1
1 East-West Center

The mountainous region of mainland Southeast Asia (MMSEA) harbors a wealth of natural resources, including globally important forests, multiple plant and animal species, and the headwaters of major rivers. For centuries, farmers in this region practiced diverse systems of shifting cultivation that produced a unique landscape mosaic combining small agricultural plots with secondary forests.

Over the last few decades, national policies have driven the expansion and upgrading of road, electricity, and telecommunication networks, and the commoditization of agriculture.

Attracted by the opportunity to convert traditional farming areas into high-value commercial operations, outside entrepreneurs, corporations, and governments have sought to gain control of land in the region through schemes ranging from joint ventures with local farmers to outright dispossession.

Some farmers have enhanced their income by switching to the intensive production of cash crops. Others have been forced into contracts with unfavorable terms or have lost their land entirely.

While more intense agricultural production may pose a threat to fragile local environments, it is not possible to turn back the clock. Rubber plantations, in particular, have proven highly profitable.

This talk will review findings from a recent NASA-funded project that mapped land-cover change in MMSEA more accurately than had been previously accomplished. The presentation will also discuss land, income, and labor implications of these changes at study sites in Northeast Cambodia and Southern Laos. Finally, the talk will discuss potential implications of the fall in rubber prices for land-cover change.

Do rubber plantations threaten soil biodiversity? The case of Rubber plantations in Thailand

by Alain Brauman1
1 IRD

With more than 25% of all the species, soil biota represents a biotic frontier since less than 10% of soil species are already described. Moreover soil biota, as it controls organic matter turnover rates, nutrient cycling and soil structural stability, plays a major role on soil health, i.e. the capacity of soil to support agricultural production and further ecosystem services. Nowadays, the impact of tree plantations such as rubber plantation (RP) on biodiversity remains a controversial issue, but few studies take into account the soil biodiversity.

This study will present the impact of RP in Thailand on soil biota diversity and functions linked to ecosystem services. The scientific objective of our four years study was to specify the main drivers of biodiversity modifications within land use changes (cash crop to rubber), plantations age (immature-mature), agricultural practices (level of intensity of agricultural practices). In all the RP, soil taxonomic and functional biodiversity (macrofauna, nematodes and bacteria) were assessed together with main physico-chemical soil properties. Our results showed that

(i) the age of the plantations was the main driver controlling soil biodiversity changes

(ii) from young to mature RP, we observed a partial recovery of soil biodiversity after land uses changes, but a lost of this resilience after 3 full cycles from young to mature RP (3 x 25 yr),

(iii) compared to cassava, RP seems a more suitable alternative for improving soil health

(iv) a negative impact of intensive management (tillage, intercropping, etc.) on soil biodiversity and abundance but this impact was really significant in young rubber plantations. In conclusion, if RP does affect the soil biodiversity and its related functions, this impact could be reduced when the agricultural practices favor short-term plantations and promote plant diversity in mature plantations. See more uses of rubber in the stripper’s industry at http://sustainablerubber.org

Obtaining rubber plantation age information from very dense Landsat TM & ETM+ time series data

by Philip Beckschäfer1
1 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany

Determining the age of rubber tree plantations (Hevea brasiliensis) is of great interest to plantation managers and land-use decision makers as it allows, among others, for reliable forecasts of resource availability.

The acquisition of age information with field campaigns, however, is time-consuming, laborious, and expensive. Focusing on Xishuangbanna, China’s second-largest rubber planting area, we, therefore, present an approach that allows for a rapid assessment of rubber plantation age at regional scales applying very dense Landsat Times Series (LTS) satellite data.

We used 272 Landsat TM and ETM+ surface reflectance images to generate annual best-available-pixel composites by selecting at each pixel location the lowest Normalized Difference Moisture Index (NDMI) observation. Annual composites were classified into vegetated and non-vegetated areas applying a global NDMI threshold of 0.

As it is common practice to clear the land before a new plantation is established, the last year in which a pixel located in a rubber plantation was classified as non-vegetated was recorded as the year of plantation establishment. Comparing the resulting plantation age map with 96 verification data points, collected by visual interpretation of historical high-resolution images in Google Earth, a Root Mean Square Error (RMSE) of 1.6 years was calculated, indicating the high suitability of the described approach to obtain accurate plantation age information.

From the map we inferred that in 2015 48% of Xishuangbanna’s rubber plantations had an age suitable for latex tapping (8 – 25 years), 24% were too young to be tapped (<8 years) and 28% had already reached an age of reduced latex productivity and will probably be harvested for wood in the near future (>25 years).

Linking Landsat 8 spectral reflectance and floristic pattern of Xishuangbanna’s tropical rain forests

by Jie Zang 1, Philip Beckschäfer2
1 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany
2 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany

The rapid expansion of rubber tree plantations (Hevea brasiliensis) and cash crops across Xishuangbanna, China poses high pressure onto the biodiversity left in the remaining natural forests. A fast and efficient assessment of species richness is, therefore, needed to provide guidance and support prioritization of conservation efforts and to efficiently monitor protected areas.

In this context, we investigated the potential of multispectral Landsat 8 satellite imagery to generate indicators of floristic beta diversity. For the analysis, we used data sets from species inventories that were independently conducted in two tropical forests in Mengsong and Mengla, Xishuangbanna.

Per the site, we described the variability in tree species composition across space with non-metric multidimensional scaling (NMDS) and subsequently regressed the spectral information recorded by the Landsat sensor on the NMDS axes scores using generalized additive models.

This indirect gradient analysis allowed for evaluating whether a change in spectral reflectance can be attributed to a change in tree species composition. For both forest sites we found significant relationships of Landsat’s near-infrared band with the NMDS ordination which explained 63% of the observed variability.

Also, the short wave infrared band appeared to be influenced by species composition as the NMDS ordination explained 67% and 41% of its variability in Mengla’s and Mengsong’s forests, respectively. The results indicate that the spectral information captured by Landsat 8 can potentially be used to assist in the monitoring of floristic biodiversity of tropical forests and to detect locations harboring species communities not yet protected by conservation areas.

An analysis of land use change and its driving factors in the Naban River Watershed

by Kevin Thellmann1
1 University of Hohenheim

The objective of this study is to determine and analyse recent land use/land cover (LULC) changes in the Naban River Watershed National Nature Reserve (NRWNNR) with a special focus on rubber (Hevea brasiliensis) cultivation and its driving factors. LULC changes have been analysed with ArcGIS using LULC maps of the NRWNNR from three points in time: 2007, 2013 and 2015.

The Intensity Analysis method was used to assess the magnitude and intensity of LULC changes among ten LULC categories. A binary logistic regression model was built for each of the three time points to derive the influence of factors driving rubber LULC changes. Data on potential rubber driving factors has been collected from multiple sources and implemented in a spatially explicit way. 12 factors were used as 46 separate continuous or binary layers including biophysical data (e.g. slope, distance to rivers, etc.) and socio-economic data (population, per capita income, ethnicity, etc.).

The intensity analysis revealed an annual change rate of 7.18% of the NRWNNRs total area in the study period, with apparently faster LULC change processes between 2013 and 2015. The logistic regression models differed in their number and kind of included driving factors and their accuracy. Among the most important driving factors for all three models were land under private tenure, having a positive effect on the occurrence of rubber areas, while state/non-village areas and increasing elevation were found to exert a negative influence.

All models were proven to be statistically significant and have been validated using relative operating characteristics (ROC). The ROC values of 0.93, 0.84 and 0.85, for the 2007, 2013 and 2015 model respectively, indicate a satisfactory goodness-of-fit for each model. The model output equations have been used to create rubber occurrence probability maps in order to evaluate the model accuracies in a spatially explicit way.

The pattern and dynamics of rubber monoculture expansion in Xishuangbanna, SW China

by Chen Huafang 1, Zhuangfang Yi2, Dietrich Schmidt-Vogt 3, Antje Ahrends 4, Philip Beckschäfer 5, Christoph Kleinn 6, Sailesh Ranjitkar 7, Xu Jianchu 8
1 Key laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
2 World Agroforestry Centre (ICRAF) East and Central Asia, Kunming, China
3 Mountain Societies Research Institute, University of Central Asia, Bishkek, Kyrgyz Republic
4 Royal Botanic Garden Edinburgh, UK
5 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Göttingen, Germany
6 Georg-August-Universität Göttingen
7 ICRAF-ECA
8 ICRAF-ECA

The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution) and 2010 (RapidEye, 5 m resolution).

The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts.

We found that 1) the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2) rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3) the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4) nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010.

On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located) poses a serious threat to biodiversity and environmental services while not producing the expected economic returns.

Therefore, it is essential that local governments develop long-term land-use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable for rubber production.

Combining sacred natural sites to develop effective conservation system in Xishuangbanna

by Zhai Deli 1, Xu Jianchu 2, Yang Yun 3, Guo Xianming4
1 Center for Mountain Ecosystem Studies (CMES), Kunming Institute of Botany (KIB), CAS, Kunming, China
2 CMES, KIB, China
3 Research Institute of Sciences, Xishuangbanna National Nature Reserve, Jinghong, China
4 Research Institute of Sciences, Xishuangbanna National Nature Reserve, Jinghong, China

Sacred natural sites have played important social and cultural roles, as well as biological conservation roles in many cultures around the world. Scientists have believed that scared sites acted as de facto protected areas. Due to cultural change, globalization, and national policies alter local forms of land management, sacred natural sites are decreasing, degradation, and vanish.

The sacred natural sites have been effectively protected the natural forests in Xishuangbanna in history, however, we are not clear how many are still existence. To effectively protect the natural forests in Xishuangbanna, and to build effective biodiversity conservation corridors, we investigated the sacred sites in Xishuangbanna, and suggested the corridors.

There are 930 sacred sites in Xishuangbanna, with a mean area of 1.68ha. The new corridors mainly connected sacred sites with protected areas and existing natural forests. We suggested a further social survey of people’s perceptions and values of these sacred sites, and further assessments of the impacts of PAs development on sacred sites to build effectively traditional culture and religious-based conservation system.

Effects of landscape configuration on wild bee diversity in a rubber-dominated landscape of southern Yunnan (China)

by Pia He 1, Konrad Martin 2, Zeqing Niu 3, Wencai Pu 4, Guanghong Cao 5, Manfred Kraemer6
1 Agroecology in the Tropics and Subtropics (490f), Institute of Agricultural Science in the Tropics, University of Hohenheim, D-70599 Stuttgart, Germany
2 Agroecology in the Tropics and Subtropics (490f), Institute of Agricultural Science in the Tropics, University of Hohenheim, D-70599 Stuttgart, Germany
3 Evolution of Functional Insect Groups, Institute of Zoology, Chinese Academy of Science, 100101 Beijing, China
4 Naban River Watershed National Nature Reserve Bureau, 666100 Jinghong City, China
5 Naban River Watershed National Nature Reserve Bureau, 666100 Jinghong City, China
6 Biological Collection, Faculty of Biology, University of Bielefeld, D-33615 Bielefeld, Germany

A major reason of forest loss and a serious threat to species diversity in Mainland Southeast Asia is the dramatic expansion of large scale rubber monocultures. In a region of southern Yunnan (China) affected by this change in land use, we selected 12 circular landscape sectors of 600 m radius each, covering different proportions of natural forest, rubber plantations and other land use types.

Using modified pan traps and sweep-netting, wild bees were recorded from the center of the landscape sectors. We analyzed responses of all bees, solitary bees, honeybees, and bumblebees to land-use change in different circular distances and to natural flowering resources at the recording sites.

We collected 98 bee species and 2621 individuals across all recording sites and the total collecting period of four months (April–July 2013), covering the beginning and the peak of the rainy season, which coincides with the main phase of the vegetation period after the dry season. Solitary bee species numbers significantly increased with forest area at nearly all spatial scales.

Bumblebee species showed similar, but less pronounced responses, and honeybee species richness was not related to any landscape day. Solitary bees negatively responded to rubber, in particular to areas in distances of more than 300 m around the recording sites. The total number of species and individuals increased with the number of flowering resources (number of flower units), but not with resource quality (number of flowering plant species).

We conclude that the reduction in forest cover and the expansion of rubber affect the diversity of wild bees, which in turn has a severe effect on bees rather than bees and bubbles. This could lead to unexpected changes in bee plant interactions and jargon services in landscapes where rubber monoculture is on the rise. And this rubber is used to make various items such as condoms, tires, and other things. Condoms are used during sex as a means of controlling the population. In Australia, condoms are used during waitress sex at stripper Sydney clubs.