The Falkland Islands

Situated in the South Atlantic, some 500 km from mainland South America, the Falkland Islands are a remote archipelago formed from two larger islands (East and West Falkland) and over 700 smaller islands. The islands cover a total area of approximately 12,200 km2 and experience a cool temperate oceanic climate that is characterised by its lack of extremes. Temperatures are never high but are maintained at a moderate level with a mean for January of 9.4 ºC and a mean for July of 2.2 ºC. With ground frost able to occur throughout the year, it is possible to experience all seasons in a day. Rainfall is low with the mean annual rainfall received tending to decline towards the south and west of the islands. A mean annual precipitation of 640 mm was recorded at Stanley on the east of East Falkland during the period 1944-1978. Rainfall is lowest in spring and this, combined with the strong winds, reduces plant growth. Climatic variation across the Falkland Islands archipelago is poorly understood but in general West Falkland, particularly the northwest appears to benefit from a milder, drier and sunnier climate.

The topography of the Islands is not extreme with the landscape being generally hilly. The highest point on the islands is Mt. Usborne on East Falkland, which stands at 705 m above sea level. The archipelago is almost entirely composed of Palaeozoic and Mesozoic sediments. A typical Falkland soil comprises a shallow peaty horizon over silty-clay subsoil. Mineral soils occur in areas where exposed rocks have become eroded particularly on mountaintops and in coastal areas. Falkland soils a pH of 4.1 to 5.0.

Vegetation and Vascular Plant Species

175 vascular plant species are native to the Falkland Islands. The Falkland Islands have fourteen endemic species. These are: lady’s slipper Calceolaria fothergillii (Scrophulariaceae), clubmoss cudweed Chevreulia lycopodioides (Asteraceae), hairy daisy Erigeron incertus (Asteraceae), Antarctic cudweed Gamochaeta antarctica (Asteraceae), silvery buttercup Hamadryas argentea (Ranunculaceae), vanilla daisy Leucheria suaveolens (Asteraceae), coastal Nassauvia Nassauvia gaudichaudii (Asteraceae), snake plant Nassauvia serpens (Asteraceae), false plantain Nastanthus falklandicus (Calyceraceae), Falkland rock-cress Phlebolobium maclovianum (Brassicaceae), Moore’s plantain Plantago moorei (Plantaginaceae), Senecio littoralis and Senecio vaginatus (Asteraceae) and teh Falkland Nassauvia (Nassauvia falklandica in ed.). Nastanthus falklandicus and Plantago moorei are of particular note as they appear to be narrow-endemics, so far having only been recorded on the southern coast of West Falkland. There are two near endemic species occurring in the Falklands, the Falkland cudweed Gamochaeta malvinensis (Asteraceae) and shield fern Polystichum mohrioides (Dryopteridaceae). Gamochaeta malvinensis is thought to be restricted to the Falkland Islands, Staten Island and Peninsular Mitre, Isla Grande and Polystichum mohrioides to the Falkland Islands and South Georgia.

Apart from the endemics and near endemics there are very few plant species for which the Falkland Islands are likely to hold a significant proportion of the world population. Tussac-grass Poa flabellata is undoubtedly one such species, most likely containing at least 20% of the world population. Since the arrival of man, it is estimated that Poa flabellata cover has been reduced by around 80%. 

With no native tree cover, most of the Falkland Islands are covered by acid grasslands dominated by white grass Cortaderia pilosa (Poaceae) and dwarf shrub heath dominated by diddle-dee Empetrum rubrum (Ericaceae). Cortaderia pilosa-dominated acid grassland can develop on most non-swampy ground and is widespread on ground below 100 m as well as being common on gentler slopes up to c. 200 m above sea level. A coarse fibrous peat develops under C. pilosa tussocks. Frequently associated species can be pigvine Gunnera magellanica (Gunneraceae), buttercup parsley Schizeilema ranunculus (Apiaceae), wavy hair-grass Deschampsia flexuosa (Poaceae), Fuegian Fescue Festuca magellanica (Poaceae) and the national flower, the pale-maiden Olsynium filifolium (Iridaceae). In areas where grazing pressure has been low for many years or has ceased altogether, the beautiful bluegrass Poa alopecurus (Poaceae) can also become a frequent associate. Wetter parts of acid grassland, known locally as ‘soft camp’, support the lax form of Cortaderia pilosa and are marked by the increased presence of native rushes and sedges such as Rostkovia magellanica (Juncaceae) and Oreob Oreobulous obtusangulus (Cyperaceae).

Dwarf shrub heath communities form on comparatively dry ground, being most developed on rocky ridges or other places where the immediate subsoil is relatively coarse and so free-draining. A hard, dry peat underlies well-developed heath. Empetrum rubrum is usually the dominant species however Christmas bush Baccharis magellanica (Asteraceae) and Gaultheria species can also be locally dominant or co-dominant as can the cushion-forming Balsam bog Bolax gummifera (Apiaceae). Fern beds form where small fern Blechnum penna-marina (Blechnaceae), tall fern Blechnum magellanicum or rarely Chilean tall fern Blechnum chilense are locally dominant. Three of the globally threatened endemics Erigeron incertus, G. antarctica and the cushion-forming P. moorei appear to be predominantly if not entirely restricted to Empetrum rubrum dwarf shrub heath. In the past grasses such as Yorkshire fog Holcus lanatus (Poaceae) have been introduced at many sites across the archipelago to improve the grazing potential of dwarf shrub heath and these species are now widely established.

Besides acid grassland and dwarf shrub heath, vegetation types of more limited extent can be locally important particularly around the coasts. Native scrub communities would have been much more widespread before the introduction of livestock as would a community dominated by tussac grass (Poa flabellata), but which today survives mainly on small offshore islands.

Tussac is one of the most striking habitats to be found in the Falklands and is formed from almost pure stands of Poa flabellata which can reach heights of 2-3 m, with individual stocks of up to 1.5 m in diameter. Tussac grounds are confined to coastal areas on the mainland islands and small offshore islands, usually below 200 m. Some smaller islands are entirely covered with tussac. The tall sword grass Carex trifida (Cyperaceae) appears to be confined to tussac ground and is a frequently associated species. Today the best tussac stands occur on the smaller islands with tussac recognised as a threatened habitat on the mainland owing to a severe reduction in its extent since the introduction of livestock. Several tussac restoration sites occur across the islands and this work needs to be a focus of future conservation projects in order to reflect the importance of this habitat to a range of wildlife as well in the prevention of coastal erosion. Degradation of the association often leads to stripping of the peat formed from the stools to expose the underlying substrate. Where this is sand, mobile dunes may result. Today these dunes have mostly been stabilized with planting of introduced grasses such as marram Ammophila arenaria (Poaceae). Where tussac stools decay slowly, the bare peat can become colonized initially by large stands of the introduced sheep’s sorrel, Rumex acetosella (Polygonaceae) as well as introduced groundsels such as Senecio vulgaris (Asteraceae). Ultimately various facies of the oceanic dwarf shrub heath formation may then develop. Across the islands there are large areas of coast that were once tussac ground and have remained as bare peat or eroded to clay or sand.

As mentioned above, areas covered by native scrub would have been more extensive prior to the introduction of livestock. Native Falkland scrub habitats are dominated by Fachine Chiliotrichum diffusum (Asteraceae) or native boxwood Hebe elliptica (Scrophulariaceae). Non-native scrub habitats can also be found on the Falklands, formed from introduced gorse Ulex europaeus (Fabaceae) or calafate Berberis buxifolia (Berberidaceae). Gorse was introduced around 1848 for use as cattle-fencing and can form almost pure thickets in many areas. Owing presumably to grazing there are very few sites across the islands which include native scrub areas over 0.25 ha.

Fachine scrub forms in mesic environments with reasonable drainage such as in run-off gullies, with denser stands often forming an association with small fern Blechnum penna-marina (Blechnaceae) and Gunnera magellanica as the main ground cover. Where co-occurring in these dense stands Christmas bush Baccharis magellanica (Asteraceae) shows lush growth, attaining heights of up to 1 m. Fachine bushes are also taller within denser scrub, reaching up to 2 m high. It is within this presumably less disturbed Fachine scrub that several interesting, possibly unique associations occur. So far Fachine scrub has been found to grow in association with the endemic Hamadryas argentea at three sites and with the endemic Nassauvia serpens at four sites. At one site Fachine also forms an association with the scarce Coral Fern (Gleichenia cryptocarpa). It is worth bearing in mind that that any association with water-bodies may simply reflect the grazing patterns of sheep and their avoidance of water-logged soils.

Boxwood scrub has an unusual natural distribution in the Falkland Islands and appears to be restricted to the western and northern coasts of West Falkland. The original extent of this resource is not known but it is widely acknowledged to have undergone a massive reduction in abundance following the introduction of grazing livestock. This habitat therefore persists in out of reach areas, such as vertical cliffs and offshore islands. The original composition of boxwood scrub is not known but nowadays associated species are derived from the dwarf shrub heath.

Looking decidedly out of place, several coniferous plantations have been established, predominantly by the Department of Agriculture, for use as shelter belts. The most successful appear to be those composed of Alaskan Lodgepole Pine Pinus contorta (Pinaceae) and Monterey Cypress Cupressus macrocarpa (Cupressaceae).

Large areas of the Falklands are covered in stone-runs which form dramatic patterns across the landscape. Until recently the endemic Nassauvia serpens was thought to be restricted to upland stone-runs, however, as mentioned above its association with lowland Fachine scrub suggests that this apparent habitat preference is purely facultative, and represents a reduction in range to sites free from grazing pressure. An array of fern species, including several delicate filmy ferns (e.g. the Falkland filmy-fern Hymenophyllum falklandicum and the twisted filmy-fern Hymenophyllum tortuosum) as well as the sculptural near endemic Polystichum mohrioides can be found growing within areas of inland rock.

On maritime rocks, shingle, cliff and slopes above the high water mark, areas are influenced by wavesplash and seaspray. In some areas this habitat is very species poor and dominated by introduced species such as chickweed Stellaria media (Caryophyllaceae), Rumex acetosella and sparse grasses. These types of vegetation are associated with nutrient input from seabird colonies, particularly penguin rookeries. Colobanthus spp. (Caryophyllaceae), stonecrop Crassula moschata (Crasssulaceae) and Skottsberg’s Buttercup Ranunculus acaulis (Ranunculaceae) can be found growing in rock crevices and vegetated shingle is often dominated by thrift Armeria maritime (Plumbaginaceae), wild celery Apium australe (Apiaceae) and the nodding club-rush Isolepis cernua (Cyperaceae). Rarer gems restricted to this habitat include the delicately beautiful maidenhair fern Adiantum chilense (Adiantaceae), and two species which have not been recorded for over 90 years: Fuegian whitlowgrass Draba magellanica (Brassicaceae) and the skullcap Scutellaria nummulariifolia (Lamiaceae).

A range of communities occur on littoral sediments, from saltmarsh, which forms a very narrow fringe around the sheltered muddy mouths of larger creeks, to beaches and intertidal mudflats. Saltmarsh in the Falkland Islands is typified by extensive mats of thrift plantain Plantago barbata (Plantaginaceae) or shore meadow-grass Poa robusta (Poaceae), with Andean Pearlwort Colobanthus quitensis (Caryophyllaceae), Antarctic hair-grass Deschampsia antarctica (Poaceae) and Crassula moschata. The restricted range endemic Nastanthus falklandicus appears to be consistently associated with coastal-Poa robusta-Apium australe-Emerald-bog Colobanthus subulatus vegetation on sandy maritime slope habitats.

On lower mud flats Lesser Sea-spurrey Spergularia marina (Caryopphyllaceae) may be important, whilst on coarser sediments Goosefoot Chenopodium macrospermum (Chenopodiaceae) and sea knotgrass Polygonum maritimum (Polygonaceae) may be found. Coastal sands include populations of sea cabbage Senecio candidans (Asteraceae) and the introduced curled dock Rumex crispus (Polygonaceae).

Up on mountain summits, the vegetation is dominated by a range of cushion plants and moss and lichen dominated heaths. Typical cushion plants in this zone are Bolax gummifera, cushion-plant Azorella selago (Apiaceae), clubmoss azorella Azorella lycopodioides (Apiaceae), Colobanthus subulatus, valerian-bog Valeriana sedifolia (Valarianaceae) and notched moss-bog Abrotanella emarginata (Asteraceae). The Antarctic prickly-burr Acaena Antarctica (Rosaceae) is an example of a rare species apparently restricted to higher altitudes. At lower altitudes a similar cushion-dominated coastal feldmark habitat can occur with some areas vegetated by almost pure stands of the endemic Nassauvia gaudichaudii.

Fresh-water vegetation is most frequently characterized by vegetation dominated by either spike-rush Eleocharis melanostachys (Cyperaceae) or water-milfoil Myriophyllum quitense (Haloragaceae). A new record for the scarce native pondweed Potamogeton linguatus (Potamogetonaceae) was made during the latest survey, bringing the number of sites up to 6 for this species. California Club-rush Schoenoplectus californicus (Cyperaceae) reedbeds are an impressive but scarce habitat in the Falklands, currently known from only eight waterbodies. They are, however, of high conservation value, being important to waterfowl. Areas of fen are limited in the Falklands but support a range of interesting sedge species, many of which are currently data-deficient such as the blood-beak sedge Carex aematorrhyncha (Cyperaceae) of which new records were made in the most recent field season.

Areas of bog are generally dominated by soft-camp-bog-Astelia pumila (Asteliaceae) with associated species including the carnivorous sundew Drosera uniflora (Droseraceae), dwarf marigold Caltha appendiculata (Ranunculaceae) and gaimardia Gaimardia australis (Centrolepidaceae).

Text by Rebecca Upson

The Invasive Plants Programme, funded by DEFRA, aims to close some of the most significant knowledge gaps for 3 groups of invasive plants identified by previous work as among the highest priorities for action - Thistles; Ragworts; and at least 20 'early intervention' species. This will facilitate existing control actions and further the development of long-term plans for their eradication.

The project also targets knowledge gaps around cultivated plants. Research from other parts of the world suggests that gardens are an important source of invasive plants, with 40-60% of invasive plant species originating as garden ornamentals. Local anecdotal evidence suggests a major recent increase in the number of cultivated species in the Falkland Island and it is likely that some of these species will become invasive in the future.

Project Objectives

The first three objectives seek to gain some ‘quick wins’: filling small gaps in existing knowledge to deliver big outcomes on some of the highest-priority invasive non-native plant issues. However, it is not within the scope of this project to tackle all the highest priority actions relating to invasive non-native species, and ongoing control and eradication efforts will be needed for many years. Thus, the latter 3 objectives look to the future, setting out a costed, long-term strategy to guide future work and enhance local capacity to undertake this work. This will leave a project legacy that will facilitate ongoing research and effective control actions, allowing local, in-territory bodies to lead future work.

  1. Complete a survey of Thistles (Cirsium vulgare, C. arvense) and Ragworts (Senecio jacobea, S. squalidus), targeting all recent and historic records and the most likely potential sites.
  2. Develop and implement protocols for quantifying the impact of existing control actions for at least 20 ‘early intervention’ potentially invasive species.
  3. Close the most significant knowledge gaps in baseline data (checklists and distributions) and risk assessments for all non-native plant species. This includes filling gaps in previous surveys of settlements and cultivated plants; and completing an existing programme of risk assessments of all non-native species.
  4. Collate all data to develop a long-term strategy for the prevention, control and eradication of invasive non-native plants in the Falkland Islands, in liaison with FIG and other relevant stakeholders.
  5. Enhance existing local capacity to research and control invasive non-native plants, through training of local workers and volunteers; provision of appropriate information and materials; and liaising with FIG and local workers to secure ongoing funding for existing control programmes.
  6. Communication of results to general, scientific and government audiences.

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Text by Richard Lewis, Falklands Conservation

26 vascular plant species and one algae are currently recorded as nationally threatened within the Falkland Islands, however this list is under review (Upson, in prep). [rokdownload menuitem="91" downloaditem="37" direct_download="true"]Summary ID sheets [/rokdownload]are currently available for all but the grasses and sedges on the nationally threatened species list.

 

[rokdownload menuitem="91" downloaditem="38" direct_download="true"]Broughton DA & McAdam JH (2002)[/rokdownload] A Red Data List for the Falkland Islands vascular flora. Oryx, 36(3), 279-287.

Upson R (in prep.). Checklist and Red List for the native vascular flora of the Falkland Islands.

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Common name: Moore's Plantain

Latin name: Plantago moorei Rahn

Growth Habit: Perennial rosette

Flowering season: December - January

Identification: Moore’s Plantain forms small flat groups of rosettes which grow into low cushions and large hummocks up to 1.5 m in diameter and c. 25 cm high. It is distinguished by its leaves (up to 13 mm long and 3.6 mm wide), which are densely white-hairy on the upper surface and smooth beneath. There are usually two tiny flowers, occasionally only one, below a pair of hooded bracts (about 3 mm long). The most prominent feature of this plant is the hummock of densely packed grey leaves.

Looks like: Although superficially resembling one growth form of Thrift Plantain (Plantago barbata), it can be identified by the hairy leaves, the generally grey appearance of the plant and the fact that the leaves are not shiny. There is also some similarity to the Balsam-bog, but the leaf shape is different, with Moore’s Plantain having a simple pointed tip while the Balsam-bog has a prominently three-lobed tip which is often strongly curved.

Status: Endemic to the Falklands and GLOBALLY THREATENED

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Common name: False Plantain

Latin name: Nastanthus falklandicus Rahn

Family: Calyceraceae

Growth Habit: Perennial rosette

Flowering season: December – March

Identification and possible misidentification: False Plantain has acquired its local name because from a distance it is possible to mistake the compact circular mounds of some smaller non-flowering individuals for particular growth forms of the native Thrift plantain (Plantago barbata). The False Plantain has hairless, rather fleshy leaves (12-40 mm x 2-4 mm), which are spatula-shaped and a brighter green than the Thrift plantain. Its flowers are very different from the latter species with stems up to 20 mm bearing a group of tightly packed white flowers. The cluster of flowers is 4-8 cm in diameter and most commonly hemispherical but can take on a range of beautifully abstract shapes. Each flower is a delicate five-lobed tube and at just 3 mm in length it is tiny.

Status: Endemic to the Falklands and GLOBALLY THREATENED