Inger Elisabeth Måren

Forest ecosystem services and biodiversity in contrasting Himalayan forest management systems

In developing countries, the landscape surrounding agricultural land is important for maintaining biodiversity and providing ecosystem services. Forests provide a full suite of goods and services to subsistence farmers in the Himalayan agro-ecological system. The effects of biomass outtake on woody species richness and composition were analysed in forests under communal and government management. Interviews on forest use and perception of forest condition and ecosystem service delivery were conducted in farmer households bordering the forests. Significantly more woody species were found in the community managed forests. Species richness was negatively correlated with walking distance from the nearest village and increasing levels of anthropogenic disturbance. Community forests were generally less degraded than government managed forests, giving support to common pool resource management. Woody vegetation represented a crucial source of fuelwood, timber, fodder, and edible, aromatic and medicinal plants. Using a multidisciplinary framework to analyse ecosystem integrity and ecosystem service delivery enabled a finer understanding of these complex agro-ecological systems, giving support to evidence-based management and conservation planning for the future.

Management-driven evolution in a domesticated ecosystem

Millennia of human land-use have resulted in the widespread occurrence of what have been coined ‘domesticated ecosystems’. The anthropogenic imprints on diversity, composition, structure and functioning of such systems are well documented. However, evolutionary consequences of human activities in these ecosystems are enigmatic. Calluna vulgaris (L.) is a keystone species of coastal heathlands in northwest Europe, an ancient semi-natural landscape of considerable conservation interest. Like many species from naturally fire-prone ecosystems, Calluna shows smoke-adapted germination, but it is unclear whether this trait arose prior to the development of these semi-natural landscapes or is an evolutionary response to the anthropogenic fire regime. We show that smoke-induced germination in Calluna is found in populations from traditionally burnt coastal heathlands but is lacking in naturally occurring populations from other habitats with infrequent natural fires. Our study thus demonstrates evolutionary imprints of human land-use in semi-natural ecosystems. Evolutionary consequences of historic anthropogenic impacts on wildlife have been understudied, but understanding these consequences is necessary for informed conservation and ecosystem management.

Does Regulated Land Use Allow Regeneration of Keystone Forest Species in the Annapurna Conservation Area, Central Himalaya

Abstract This quantitative study assesses the ecological impacts of varying degrees of forest use, describing community structure, population structure, and regenerative capacity of the understudied but much utilized Quercus semecarpifolia Sm. in a mixed oak and Rhododendron arboreum Sm. forest. The Middle Hills of the Himalayas have long traditions of mixed farming, with animal husbandry and agriculture as interdependent components. Major biomass demands come from grazing and collection of fodder and fuelwood. In forested areas lopped fodder is one of the main components, and as elevation increases, so does its importance. Human impact has been used to explain low regeneration of these evergreen oaks. The anthropogenic disturbance gradient spanned from highly disturbed savanna-like sites to minimally disturbed shaded sites dominated by rhododendron. The population structure showed a bell-shaped distribution with a pronounced under-representation of saplings throughout the forest. Data indicated the best regeneration in the least disturbed sites. The degree of lopping was the best explanatory variable for the distribution of recruits. Factors preventing trees from surviving the sapling phase may inhibit long-term regeneration more than factors causing high seedling mortality. Results indicate that regeneration of Q. semecarpifolia may suffer to the benefit of rhododendron, which escapes biotic stress due to its poor fodder and fuelwood qualities.

Effect of anthropogenic disturbance on plant species diversity in oak forests in Nepal, Central Himalaya

Biodiversity changes caused by anthropogenic disturbance through foliage removal (lopping) were studied in Quercus semecarpifolia Sm. (oak) dominated forests in Nepal. We studied the locations of Phulchoki (Kathmandu Valley) and Ghorepani (Annapurna Region). Alpha (α) diversity, gamma (γ) diversity and different estimates of beta (β) diversity of vascular plant species were estimated in six disturbance classes characterized on the basis of lopping intensity. The effects of different levels of anthropogenic pressure on the diversity measures were analyzed by examining how β-diversity corresponds with the pattern of α-diversity. Alpha (α)- and γ-diversities show a unimodal response to disturbance gradient, but β-diversities do not follow a consistent pattern. However, the linear relationships between beta diversities (βSD and βA) and the disturbance gradient indicate that all kinds of plant species diversity measures increase up to the level where forest disturbance is intermediate. Hence, we suggest the adoption of prescribed forest utilization systems as a management policy. Such a policy has two advantages: on the one hand, it contributes to sustainable livelihoods of the people depending on local forest resources, and on the other hand, it contributes to conservation of plant species diversity.

From jhum to broom: Agricultural land-use change and food security implications on the Meghalaya Plateau, India

Human population growth in the developing world drives land-use changes, impacting food security. In India, the dramatic change in demographic dynamics over the past century has reduced traditional agricultural land-use through increasing commercialization. Here, we analyze the magnitude and implications for the farming system by the introduction of cash-cropping, replacing the traditional slash and burn rotations (jhum), of the tribal people on the Meghalaya Plateau, northeast India, by means of agricultural census data and field surveys conducted in seven villages. Land-use change has brought major alterations in hill agricultural practices, enhanced cash-cropping, promoted mono-cropping, changed food consumption patterns, underpinned the emergence of a new food system, and exposed farmers and consumers to the precariousness of the market, all of which have both long- and short-term food security implications. We found dietary diversity to be higher under jhum compared to any of the cash-crop systems, and higher under traditional cash-cropping than under modern cash-cropping.

Pastoral Abandonment, Shrub Proliferation and Landscape Changes: A Case Study from Gorkha, Nepal

Abstract Seminatural grasslands have long been shaped and maintained by human-induced fire and grazing regimes in order to utilise extensive land areas, not suitable for intensive cultivation, for the production of protein for human consumption. Changes in either management regimes have great implications for vegetation cover and composition. In this context, we qualitatively examined 18 grasslands used by transhumance agro-pastoralists in western Gorkha, Nepal, to 1) show that the pastoral landscape is undergoing change due to shrub and tree encroachment; 2) understand the role of change in grazing and fire regimes in shrub encroachment dynamics; and 3) discuss management practices and policy implications of shrub control. In this region, grassland abandonment and livestock population decline have been the overriding land-use change trend over the last four decades brought on by out-migration of local people from these marginal areas. Our results revealed that Berberis shrub encroachment started approximately three decades ago and attained a problematic cover approximately 15 to 20 years ago. The shrub encroachment drivers are discussed in the context of changed fire and grazing practices. We underscore the necessity of management intervention to maintain the services provided by these seminatural systems; and suggest synergistic application of burning, weeding and grazing, rather than sporadic single treatment.

Biodiversity and Invasibility: Distribution Patterns of Invasive Plant Species in the Himalayas, Nepal

Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low native diversity’ vs. ‘high native diversity’, is supported by the regional distribution patterns of invasive plant species in the Himalayas, Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high. Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend. Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that ‘high native diversity’ supports or facilitates invasive plant species. Further, it indicates that native and invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors.

Ecological consequences of land use change: Forest structure and regeneration across the forest-grassland ecotone in mountain pastures in Nepal

The ecotone, the spatial transition zone between two vegetation communities, is claimed to have more species than the adjoining communities. However, empirical studies do not always confirm higher richness at the ecotone. The ecotone position and structure are dynamic over time and space and it is driven by the changes in climate, land use or their interaction. In this context, we assessed the forest-grassland ecotone of temperate mountains in central Nepal by i) comparing species composition and richness across the ecotone, ii) analyzing if the forest-grassland ecotone is shifting towards the grassland center by colonizing them with trees, and iii) discussing the consequence of changed disturbance regime in the dynamics of this ecotone and the surrounding grasslands. We analyzed vegetation data sampled from belt transects laid across the forest-grassland ecotone in semi-natural grassland patches. Vegetation data consisting of species richness and composition, and size structure and regeneration of the two most dominant tree species, namely Rhododendron arboreum and Abies spectabilis, from the transects, were used to analyze the trend of the forest-grassland ecotone. Forest and grasslands were different in terms of floristic composition and diversity. Vascular plant species richness linearly increased while moving from forest interior to grassland center. Spatial pattern of tree size structure and regeneration infers that forest boundary is advancing towards the grasslands at the expense of the grassland area, and tree establishment in the grasslands is part of a successional process. Temporally, tree establishment in grasslands started following the gradual decline in disturbance. We argue that local processes in terms of changed land use may best explain the phenomenon of ecotone shift and consequent forest expansion in these grasslands. We underpin the need for further research on the mechanism, rate and spatial extent of ecotone shift by using advanced tools to understand the process indepth.

Back to Africa: monitoring post-hydropower restoration to facilitate reintroduction of an extinct-in-the-wild amphibian

Monitoring of the ecological efficiency of different restoration and mitigation measures is important to inform decision-making but can be challenging, especially in remote and low-resource settings. Species composition of the vegetation is sensitive to environmental variation, and can thus be used in restoration assessment, but this requires statistical approaches that can accommodate multivariate responses. We use principal response curves (PRC) to assess the efficiency of post-hydropower mitigation measures installed to secure the reintroduction of an extinct-in-the-wild amphibian back into its only native habitat. The endemic ovoviviparous Kihansi spray toad Nectophrynoides asperginis is only known from a wetland in the Lower Kihansi River Gorge in the Eastern Arc Mountains in Tanzania. River flow was diverted from the gorge for hydropower production in 1999, causing the spray wetland to desiccate, consequently threatening the toad and other plant and animal species dependent on the spray-zone habitat...

Recovery and adaptation after the 2015 Nepal earthquakes: A smallholder household perspective

Author(s): Epstein, K; DiCarlo, J; Marsh, R; Adhikari, B; Paudel, D; Ray, I; Maren, IE | Abstract: