**1. Introduction**

220 Biodiversity Loss in a Changing Planet

Stevens, G, McGlone, M & McCulloch, B (1988). *Prehistoric New Zealand*. Auckland,

Te Ara - the Encyclopedia of New Zealand (2009). *Wetland birds*. Retrieved 1 March 2009,

TEEB (2010). The economics of ecosystems and biodiversity. Mainstreaming the Economics

Walker, S, Price, R & Rutledge, D (2008). *New Zealand's remaining indigenous cover: Recent changes and biodiversity protection needs*. Department of Conservation, Wellington. Walker, S, Price, R, Rutledge, D, Stephens, RTT & Lee, WG (2006). Recent loss of indigenous cover in New Zealand. *New Zealand journal of Ecology,* Vol. 30, No 2, pp. 169-177. Wardle, P (1991). *Vegetation of New Zealand*, Cambridge University Press, Cambridge, United

Weeks, ES, Dymond, JR, Shepherd, JD & Walker, S (in prep.) Quantifying land-use change

Williams, M (2004). Bird communities of lakes and wetlands. In: *Freshwaters of New Zealand,*

Hydrological Society and New Zealand Limnological Society, Christchurch.

J. S. Harding, P. Mosley, C. Pearson & B. Sorrell (eds), chapter 26, New Zealand

of Nature: A synthesis of the approach, conclusions and recommendations of TEEB.

from http://www.TeAra.govt.nz/en/wetland-birds/.

in New Zealand's indigenous grasslands.

Heinemann Reed.

Kingdom.

Intra-species variations in Homo sapiens can contribute to health and resistance to infection, or alternatively to death and disease. The small isolated population of the St Kilda archipelago in the Scottish Hebrides suffered severely from many infectious diseases in the seventeenth to nineteenth centuries, with greater morbidity and mortality than the inhabitants of similar Scottish communities on other remote islands.

Fig. 1. Map of Scotland

Limited Bio-Diversity and Other Defects of

and dioxin toxicity are discussed.

Soay and Dun.

excavated in 1995.

Fig. 4. Souterrain

the Immune System in the Inhabitants of the Islands of St Kilda, Scotland 223

These infections were one of the factors leading to the failure of the island society, culminating in its final evacuation in 1930. Limited population genetic biodiversity and other factors predisposing to infectious diseases including low herd immunity and isolation, the absence of any 'healthcare professionals', malnutrition, social conditions, climatic factors

St Kilda, located at 57° 48′ N, 8° 34′ W, is an inaccessible and isolated archipelago in the Scottish Hebrides, previously inhabited for approximately 2,000 years by a small struggling community until evacuated in 1930 as a non-sustainable society. Today it has been re-

The 430 metre cliffs of St Kilda can be seen on clear days from the nearest islands in the Outer Hebrides, Harris and North Uist, which have themselves been occupied continually for six thousand years, according to archaeological evidence. Simple stone tools found on the main St Kilda island of Hirte, suggest that travellers visited St Kilda some 4,000 to 5,000 years ago. 1, 2, 3 The other smaller islands composing the St Kilda archipelago are Boreray,

The date of the first permanent settlement on St Kilda is not clear, but evidence suggests at least transient occupation from prehistoric times, harvesting the abundant stocks of fish and the sea birds, growing crops and keeping animals. A souterrain, an Iron Age earth house store about 2,000 years old, with a central long passage, and shorter passages or cells branching off, was discovered in 1844. A possible Bronze Age burial structure was

occupied by the National Trust of Scotland, and the Ministry of Defence.

Fig. 2. Map of St Kilda

Fig. 3. Picture of St Kilda

Fig. 2. Map of St Kilda

Fig. 3. Picture of St Kilda

These infections were one of the factors leading to the failure of the island society, culminating in its final evacuation in 1930. Limited population genetic biodiversity and other factors predisposing to infectious diseases including low herd immunity and isolation, the absence of any 'healthcare professionals', malnutrition, social conditions, climatic factors and dioxin toxicity are discussed.

St Kilda, located at 57° 48′ N, 8° 34′ W, is an inaccessible and isolated archipelago in the Scottish Hebrides, previously inhabited for approximately 2,000 years by a small struggling community until evacuated in 1930 as a non-sustainable society. Today it has been reoccupied by the National Trust of Scotland, and the Ministry of Defence.

The 430 metre cliffs of St Kilda can be seen on clear days from the nearest islands in the Outer Hebrides, Harris and North Uist, which have themselves been occupied continually for six thousand years, according to archaeological evidence. Simple stone tools found on the main St Kilda island of Hirte, suggest that travellers visited St Kilda some 4,000 to 5,000 years ago. 1, 2, 3 The other smaller islands composing the St Kilda archipelago are Boreray, Soay and Dun.

The date of the first permanent settlement on St Kilda is not clear, but evidence suggests at least transient occupation from prehistoric times, harvesting the abundant stocks of fish and the sea birds, growing crops and keeping animals. A souterrain, an Iron Age earth house store about 2,000 years old, with a central long passage, and shorter passages or cells branching off, was discovered in 1844. A possible Bronze Age burial structure was excavated in 1995.

Fig. 4. Souterrain

Limited Bio-Diversity and Other Defects of

*the pabulum supplied for the epidemic*.'7

human habitation and died out after the evacuation in 1930.

were counted, yet by the following spring 820 had died.

**3. Animal evolution<sup>2</sup>**

the Immune System in the Inhabitants of the Islands of St Kilda, Scotland 225

The St Kilda population up to the epidemic of 1727 were predominantly from two families of Morrisons and McDonalds generating inbred families with limited genetic diversity. St Kilda, as a 'virgin soil'environment, also had a non-immune adult population, with increased morbidity and mortality from most infections. Subsequent to that episode in 1727 which left one adult survivor on Hirte, the island was repopulated from neighbouring islands, though the inhabitants numbering over a hundred were essentially derived from only five resident families, the Gillies, MacQueens, MacDonalds, MacKinnons and Fergusons, for the remaining 200 years.7 Close consanguineous marriages were carefully avoided, and an external review of insanity caused by close intermarriages found no evidence of this problem. Consanguinity may, however, have been closer than suspected following the 'religious' leadership of a self-appointed predatory character known as Roderick for six years at the end of the 17th century. Seduction formed part of his

Comparisons with pre-Columbian North America indigenous population who had not encountered European viruses are interesting and relevant. 7 Their genetic biodiversity of histocompatibility leukocyte antigens (HLA), the genetic key to immunological defence against viruses, was 64 times less than that of the Europeans. The indigenous North American population declined from perhaps 100 million to a few million in 300 years. Smallpox is incriminated, without indisputable evidence, as causing the death of 90% of

Crosby defines the term 'virgin soil' epidemics as '*those in which the populations at risk have had no previous contact with the diseases that strike them and are therefore immunologically almost defenceless*'. John Morgan, a Manchester physician, used the term when writing about his visit to St Kilda in 1860: '*May we not explain the accumulated fatality in all these cases by supposing that in the same manner as the different cereals flourish best when planted in virgin soil, or at longer intervals of time, so it is with infectious disease? The more distant their visitation, the richer* 

The islands of St Kilda were sufficiently isolated for animals to evolve different characteristics over a few centuries. The common house mouse probably introduced by the Vikings evolved into the now extinct, but larger subspecies of the St Kilda House Mouse (Mus musculus muralis), which was found only on St Kilda. The mouse was dependent on

Another local genetically different animal is the Soay sheep (*Ovis aries*). The name Soay derives from the Viking name of island of sheep. This breed is thought to be the descendents of the earliest domesticated sheep of Northern Europe, and is physically similar to the other wild ancestors of domestic sheep like the horned urial sheep of Central Asia and the Mediterranean mouflon. Soay sheep are hardy and extremely agile animals well adapted for survival on the high cliffs of St Kilda, though they are smaller than modern domesticated sheep. Unattended, their numbers tend to build up to peak, followed by a crash, perhaps due to over-grazing or parasite infection. In the autumn of 1960 for example, 1344 sheep

They have a reduced genetic mechanism to select their coat colour compared to other sheep. Two genetic loci determine the colour which is limited to black, brown or, less commonly, white. The population of Soay sheep are a fascinating subject for researching evolution and

'instruction' of women attending counselling before marriage or childbirth.8

non-immune indigenous Americans in the sixteenth and seventeenth centuries.

Fig. 5. Village bay

The presence of three early chapels and two incised stone crosses of early Christian style were recorded by the Rev. Kenneth Macaulay. 4, 5 The continued use of Norse place names, such as Oiseval – the east hill – and Ruaival – the red hill, and archaeological finds of Norse brooches and steatite, are strong evidence of continual occupation by the Norsemen and their descendents until the 20th century. However, prior to the steamship era, the inclement climate and the small exposed rocky harbour restricted access by visiting sailing vessels.
