Belowground ecosystem services in plant communities along elevational gradients in France and Mexico – ECOPICS

ECOPICS will:
i) To answer fundamental questions concerning soil ecosystem processes and links with plant communities in specific climates and land use types
ii) To determine how the promotion of ecosystem services are beneficial (or not) to local communities and to soil quality. We define soil quality in terms of C sequestration, macroporosity, faunal and microbial abundance / diversity.
To reach these goals, we will examine two contrasting mountain biomes in temperate (France) and tropical (Mexico) climates and examine how a variety of soil, plant, soil microbial and faunal characteristics/processes are linked to the immediate climatic environment. A land use gradient will enable us to test specific hypotheses with regard to soil C sequestration and biodiversity. We aim to investigate the effect of a cultural service (mountain sports) on both the local socio-economy and soil quality.

Soil C storage potential has received considerable attention, however, there is a lack of understanding on how climatic and landuse induced shifts in vegetational, faunal and soil microbial diversity and their functionality affects soil C cycling processes, necessitating more detailed research on the mechanisms driving soil C gains and losses. We will investigate how gradients modify microbial community diversity. We will use a novel technique to determine how soil macroporosity modifies SDOC transport via infiltration. A study of root traits and root morphology, linked to the microbial diversity present, will provide unique data.

The landuse gradient to be examined will permit us to quantify the effects of anthropogenic disturbance on soil quality. However, we need to be able to integrate information into landuse management plans within the specific context of mountain communities promoting eco-tourism. A detailed socio-economic impact assessment and collaboration with identified local groups will take place.

We will use elevational gradients as a time-for-space substitution. Due to the expected contrasting changes in root/shoot biomass and traits, and in faunal/microbial community composition, along the temperate and tropical elevation gradients, we hypothesize that these changes will influence three major components of C sequestration, i.e. root C input, litter decomposition rates and C stabilization in soil aggregates. Results should provide us with key clues as to the mechanistic bases behind major shifts in C and nutrient cycles along elevation gradients. As well as an elevational gradient, will investigate a gradient linked to the types of landuse often observed on mountains.

Fieldsites are located at Mexico’s highest mountain, Pico de Orizaba and in France at the Massif de Belledonne. Vegetation will range from montane to subalpine forest, to alpine herbaceous communities beyond the treeline. Soil physical and chemical properties (e.g. soil organic carbon, DSOC, N and certain inherent chemical properties) will be measured using the same field and laboratory protocols in the two countries. We will evaluate species, root traits, and decomposition in plant communities along the gradients. Soil fauna sampling will focus on the identification and estimation of native and exotic earthworm communities at each elevation in an aim to determine the link between plant species, root traits, earthworm community size and composition and soil aggregation. We will examine how vegetation alters rainfall infiltration and DSOC transport along biotic soil macropores. We will use a phylogenetic approach to assess microbial diversity, thus providing additional insights into theprocesses that organize these communities.

A socio-economic impact assessment will allow us to estimate the impacts of ecotourism on local communities and working with these stakeholders, we will draw up a management plan, taking into account community needs and results on soil quality.

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Altitude integrates changes in the various conditions that determine soil carbon (C) storage, including temperature, soil moisture, atmospheric pressure, litter input, radiation and soil weathering. Although soil C stocks generally augment with increasing elevation, the mechanisms by which this occurs are not known. Soil C sequestration is heavily influenced by input rates and decomposability of organic matter, transport to deeper soil horizons through macropores and physical protection in aggregate complexes. We will investigate how elevation acts as an environmental filter on belowground plant traits and soil microbial and faunal communities. We hypothesize that shifts in the ratio of functional groups due to climate, alter soil C sequestration rates in both tropical and temperate climates. However, elevational gradients are often affected by anthropogenic-induced gradients, which can be managed in a way that an elevational impacts on soil cannot. Therefore, using the same techniques, we will investigate how landuse gradients impact soil C sequestration along the elevational gradient. How landuse induced shifts in belowground plant traits, soil microbial and faunal diversity and functionality affects soil C cycling processes will be determined.

Land use change is widely recognized as a net source of greenhouse gas emissions at the global scale, mostly because these emissions are attributed to losses from aboveground terrestrial pools such as deforestation. Deforestation also impacts severely livelihoods, wildlife and soil quality. Finding alternatives to tree logging in mountain regions requires assessing and promoting ecosystem services. At Mexico’s highest mountain, Pico de Orizaba, deforestation in the cloud forest still continues, causing climate and ecological perturbations as well as major soil degradation. In Belledonne, French Alps, tree logging is controlled and the financial income of local communities is more recently assured by eco-tourism, although recent over-use of trails is accused of causing disturbance such as soil erosion. By performing a socio-economic impact assessment of the effects of ecotourism (actual or future), on local communities, we will draft a management plan with the aim of promoting a service(s) depending on the needs of those communities and integrating the results of the ECOPICS project.