Project Overview

Freshwater lakes on the Falkland Islands provide a unique biological resource yet these aquatic ecosystems are virtually unexplored. Some sites are of potential value for conservation but environmental criteria are currently lacking. Lakes, such as Lake Sulivan (West Falkland) are high value sites for bird life and many others support poorly known endemic animal and plant species.
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Background

The little work that has been done on the islands freshwater lakes indicates that species endemism could be high. In addition to the native trout, there are also several species of freshwater shrimp and aquatic plants that are only known from the Island's lakes and ponds.

Native freshwater fish stocks are now degraded by the introduction of exotic species and it is likely that less conspicuous organisms in lake communities are similarly threatened. Environmental change affects lakes in many ways, through species interactions, habitat disturbance, local pollution and even global climate change.

One particularly convenient way of detecting environmental change trends in remote locations is to utilise the historical archive of sub-fossil remains in lake sediments. These records can provide information about past changes, not only about species biodiversity but also about the drivers of species changes, water quality, land use and climate.

Aims

The FI-BRIL Project is an initial study funded by the British Government and has two principal aims: first to carry out a brief survey to define the range of lake types present using water quality characteristics and thus establish reference information; second, to select two contrasting Falkland Islands lakes for sediment coring and for making biological collections.

Physico-chemical attributes of each site will also be measured and lake sediment cores will be collected where possible. Any sediment cores will be returned to the UK for examination.

The results of sediment analysis will enable the recent environmental histories of the two contrasted sites to be elucidated. These data will be invaluable in defining present and past ecological conditions and also in detecting the extent, rate and causes of any ecologically significant environmental changes occurring in the region. Sediment pollen and diatom (siliceous algae) records will be used principally to indicate recent vegetation and water quality changes respectively.

The past and present species assemblage data will enable the setting of conservation base-lines for aquatic diversity at each site. Modern samples of invertebrates and micro-algae from the two pilot study lakes will be returned to the UK for detailed taxonomic analysis at the Environmental Change Research Centre at 香港六合彩 and the Natural History Museum, London and elsewhere.

The work should contribute significantly to meeting some of the biodiversity obligations imposed on the UK's Dependent Territories by the Convention on Biological Diversity. The work will also help identify the status and nature of environmental change in the lakes of the region.

The results are published in the international scientific literature, see Flower (2006) and Flower et al. (2012).

Work Programmes

The specific aims of field investigations are:

To make initial on-site determinations of water acidity and conductivity and to collect water samples for more detailed chemical analysis (in the UK). Freshwater lakes in various locations across the Falkland Islands will be sampled.
To make initial descriptions of each lake, noting catchment characteristics, water supply and aquatic vegetation.
To select two contrasted lakes for determination of bathymetries and for biodiversity sampling (micro-algae, aquatic plants and invertebrates).
To collect sediment cores from these two lakes using a gravity corer. The cores will be sectioned in the field and returned to the UK for microfossil and lithostratigraphic analysis.
To undertake trial sediment coring in two or more lakes. Any cores will be subsampled in the field and returned to the UK to check for microfossils.

Specific analytical aims are:

To identify as far as possible the species of invertebrates (Crustacea, Copepods, Chironomids, and Ostracods if present) as well as the species composition of the micro-algae (diatom) communities present at the two contrasted lakes.
To establish a chronology and sediment accumulation rates for each sediment core over the past 200 years using well-established isotopic techniques based on the decay of the radioisotope 210Pb and the assay of weapons fallout 137Cs. Sedimentary inventories of these radionuclides should also reveal interesting data on deposition patterns in this remote region
To analyse sediment core sections for microfossil assemblages (pollen and siliceous microalgae).
To perform lithostratigraphic analysis on the mineral component of each core to indicate changes in land use or, in conjunction with other records, where the catchment is known to be undisturbed, of climate change.
To perform rate of change analysis on each stratigraphic profile to infer species diversity stability or otherwise at each site.
To use the species information present in the sediment archive to detect the presence of recently introduced species or the loss of any formerly common taxa and to define the time-scales of any such changes.
To use the range of diatom species present in each core to test ideas about the effects of biogeography and water quality type on the distribution of aquatic species present at this remote island location.
Results Some results are now published in Flower, R.J. 2005. A taxonomic and ecological study of diatoms from freshwater habitats in the Falkland Islands, South Atlantic. Diatom Research 20:23-96.

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