A Review of the Ecological Functions of Reed Bamboo, Genus Ochlandra in the Western Ghats of India: Implications for Sustainable Conservation

K. SijiMol, Suma Arun Dev*, V. B. Sreekumar

First Published March 1, 2016

Ecological benefits of reed bamboos

Carbon sequestration potential

Although bamboos are grasses, they possess the remarkable ability to sequester carbon through photosynthesis and to lock carbon in the fibrous root system which is an important aspect of the forest ecosystem and the carbon sink [63–64]. Through their inherent ability to take up large amounts of CO2 and convert it into oxygen, reed bamboo forests can help regulate CO2 emissions that contribute to global warming. The CO2 absorbed by the reed bamboos does not release back into the ecosystem as it is retained by the plant, and after harvesting, the culms and leaves are used for various value added products in industries. Thus, the reed bamboos serve as a carbon sink and the resulting environmental benefits are immense. Bamboo thus serves as an important niche for carbon conversion and locking [65] and hence the broad spectrum of bamboo products and services should be regarded as an important contribution to mitigating climate change.

Soil and water management potential

Reed colonization exerts a significant physical, chemical and biological impact on the soil. The biological activity of the fibrous root system of Ochlandra species with the micro organisms in the top layers of soil strata result in the formation of water stable macroaggregates. Thus the pure reed patches of Ochlandra species has been considered a stable vegetation climax capable of improving the physical properties of the soil and thereby stabilizing slopes and preventing land degradation [66]. Most of the Ochlandra species are riparian in origin as the river banks provide diffuse sunlight and moist fertile soil for healthy reed growth. O. spirostylis acts as a potential species in river bank stabilization [54].

Ochlandra species resist uprooting in winds and form population climaxes. Reed bamboos possess a large mass of foliage, culms and dry stalks which add large quantity of organic matter to the soil and help in the refinement of soil fertility, both physical and chemical aspects, through nutrient cycling. The soil in reed growing areas is rich in carbon content and replenishing nutrient characteristics by growing reeds has been suggested to improve the soil fertility in degraded soil [67–69].

Leaf litter plays a significant role in determining the structure and function of the forest ecosystem by acting as an energy source and a nutrient reservoir for heterotrophic organisms. A wide range of faunal populations have been observed in the reed growing soil which have a significant role in litter decomposition and soil enrichment. The water holding capacity of reed growing soil was also found to be higher when compared to non-reed areas due to the presence of the fibrous root system. Quality and quantity of water are two essential characteristics for the effective management of watersheds. Reed bamboos form an umbrella-like canopy in the evergreen forest areas. Since the vegetation is riparian in nature, it forms a kind of wall that checks the loss of flow in rivers [47]. Ochlandra species has thus been reported as a priority bamboo species to be conserved for the effective soil management of the Western Ghats [70].

Reeds as a keystone species

Reed bamboos function as a keystone species in evergreen forests, influencing the survival of many associated species and their ecological niches. It forms an important food source for the survival of gaur, Bos gaurus and Daubentonia madagascariensis which feed extensively on Ochlandra species [71]. Ochlandra species provides food and shelter for several forest fauna [72]. The fruiting of O. wightii supports the population of an endemic rodent Platacanthomys lasyrus [68]. The butterfly larvae of Parantirrhoea marshalli inhabit the leaves of Ochlandra travancorica [73]. Wild pigs feed on the fruit of O. ebracteata and the dried fruit is used as cattle feed [74]. The major Ochlandra growing areas are reported as elephant corridors [75] and bamboo culms are one of their favorite food delicacies. The arbuscular mycorrhizal fungi have a strong association with the fibrous root system of Ochlandra species [76]. Similarly, the faunal population of the reed growing area harbors diverse arthropods and annelids [77]. Reed bamboos also have a close association with the anurans (Raorchestes ochlandrae) of the Western Ghats which inhabits the hollow internodal regions of O. setigera [78]. Raorchestes chalazodes, a small frog, has been observed on the stalks of O. travancorica and O. scriptoria throughout its distribution zones [79]. As these frog species can only breed in reed bamboos, the unscientific over-harvesting of reed bamboos may destroy its breeding habitats and have a negative impact on the long term survival of anuran populations in the Western Ghats.

Ecosystem services

Strategies that support the ecosystem

Ochlandra travancorica and O. wightii have developed many adaptive strategies which help their successful existence in the wet terrains of the Western Ghats. These strategies are: the fibrous root system, vigorous growth, the production of baccate caryopses, adaptability to riparian life, absence of fruit dormancy and mycorrhizal associations. Healthy clumps of reed bamboos form an umbrella-like canopy which resists uprooting in winds and assists in the formation of population climaxes [80].

Socio-economics and livelihood potential of reed-based industry

Non-Timber Forest Produce (NTFPs) is considered eco-friendly, since harvesting causes less damage to the ecosystem than, for example, illegal logging. Reed bamboos are considered one of the most important NTFPs because of the subsistence and livelihood support they provide for the economically weaker strata of society. In India, bamboo handicraft industries are widespread in the southern states, but this traditional sector is seeing a gradual decline in reed availability due to over-exploitation. The deforestation of reed areas for agriculture, multi-purpose river valley projects and permanent settlements add to the decline of reed resources and this affects the stability of the cottage industries [81]. Ochlandra species in particular plays a significant role for the livelihood of rural communities by providing source materials for construction, fencing, and handicraft industries, fodder for cattle and byproducts for medicinal purposes. The traditional tribal community, the Kadar of the Western Ghats, utilizes reed bamboos extensively for their livelihood as part of their culture [68, 82] (Table 3). Ochlandra species are also associated with some religious rituals during which immature culms of O. scriptoria are collected, crushed and made into a flower like product called 'odappuvu' in northern Kerala (Fig. 1E) [83].

Table 3. Economic and industrial utilization of various Ochlandra species [30, 82 & 83].

Table 3. Economic and industrial utilization of various Ochlandra species [30, 82 & 83].

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Bamboo has multiple uses and plays a crucial role in culture, art, industry and construction [84]. It is planted for hedges and used for landscaping [85]. In Kerala, bamboo cottage industries mainly use Ochlandra spp. (reed bamboos), particularly O. travancorica because of its high lignin and fibre content. For the last few years, the utilization of reeds has moved from cottage to commercial industry for paper and pulp production. About three million people in Kerala depend on the reed industry for their livelihood and about 3,500 local people are engaged in reed extraction and its transport from the forest (Fig. 1F). Kerala State Bamboo Corporation Limited (KSBC), an agency promoting reed based industry in Kerala State, was established in 1971 to regulate the pattern of reed extraction through the collection and distribution of reeds as well as the trading and marketing of the finished products [33, 86]. Some recommendations have been put forward to improve the functioning of institutions, as well as of the industries, in order to promote and manage the sustainable use of reed resources [87]. However, greater efforts should be directed towards improving reed production through appropriate technological interventions. Furthermore, existing policies for the sustainable use of resources need to be updated if the livelihood potential of reeds is to be sustained.

Thanks for sharing, an interesting and informative article

 great answer Iuliana Florentina Gheorghe