R/N AT IF LO/2#8 TUSSAC GRASS IN THE FALKLANDS I.J STRANGE, C.J PARRY, M.C PARRY & R.W WOODS FALKLAND ISLAND FOUNDATION PROJECT REPORT In collaboration with the Falkland Island Government. Funded by: The Falkland Islands Government Mr. Robert Gibbons. JULY 1988 • • -*£*■■■■■'— £ yi. an —3 1*# ,, •.;:; • • . ..,y, ;Vv £ •: .. •*. } i « g ■C ’(H; ■ ■ - ■■ feet. 'J-m " U • - K,V • “ *tv j] i 1 I TUSSAC GRASS IN THE FALKLAND ISLANDS. ] r_ - CONTENTS ] 1. SUMMARY. 2. TUSSAC GRASS SURVEY: Ian Strange. ] 3. TUSSAC ISLAND SURVEY. —! I List of Islands. __ i 4. TUSSAC DISTRIBUTION SURVEY. ] Robin Woods. ] 5. EXAMPLES. Patterns of change in tussac cover: I ] I - J l J -1 J 1 \ J - o ■"1 -J ] CONTENTS. 1. Tussac Grass in the Falkland Islands: Summary. ! f Introduction. Overall trends in Tussac cover. “ a 1 Grazing and Tussac Conservation of Tussac. Recommendations. - a ; Appendix 1. Methodological differences between the Woods and Strange tussac reports. Appendix 2. Pristine tussac islands and other sites of high - Q-) conservation value. 2. The Falkland Islands: Tussock Grass Survey. Ian Strange. Introduction. i i Historical. Early Description and Nomenciature. a Early Distribution of Tussock. Decline of Tussock Grass by Natural Causes. Depletion of Tussock Grass by Man.. ^ Present Day Decline of Tussock, Estimates of Original Tussock covefe*^ - '•* M'; Ecology. The Plant. j The Tussock Ecosystem. i The Tussock Habitat'and Environment. • V-- The Survey. Introduction. ■.. • J. Survey Methods. Survey results. Disscussion. Recommendations. 1 ! Table A. - Estimated Original Tussock Area in Stocked Offshore J I Islands. i Table B. - Tussock Islands With No Evidence of Spoliation. 1 Acknowledgements. i 3. Tussock Island Survey: List of Islands. Ian Strange. i 4. Falkland Islands: Tussac Distribution Survey. Robin Woods. Background to the survey. J. Methods used. Results. Analysis of 1956 Material. J Analysis of 1983 Material. List of Islands selected for Ecological Survey. J. 5. Patterns of Change - Tussac Cover: Examples. i •-: Jj . ■-'-a : --"-=3 i ! SUMMARY - I "1 --i 11 »§ ii v ■ - J !, ■i i. i r 1 - - ■: , : ■ -n ' , : -n i j ] -i ■ j -n J '1 J 1 H 1 TUSSAC GRASS IN THE FALKLAND ISLANDS SUMMARY 1. Introduction. 1.1 The tussac grass community constitutes a characteristic natural vegetation type, 1 the most important single wildlife habitat in the islands, and a valuable resource for pasturage. 1.2 The survey arose from concern over the general decline of tussac in the _j Falklands. In January 1986, the Executive Council of FIG decided that a comprehensive survey of tussac should be undertaken as a basis for the development of guidelines or legislation for grazing management and for decisions upon the total protection of certain islands. Given that a thorough ground investigation would be exceedingly expensive, an alternative approach was adopted in the first instance using information already to hand. A photogrammetric desk survey, using interpretation of aerial photographs to produce a base-line map of tussac distribution in 1956 and assessing change by comparison with photographs taken in 1983, was undertaken by Cynthia and Martin Parry under the supervision of Robin Woods. At the same time, Mr Ian Strange collated his extensive on-site observations to produce a general overview of the status of tussac both in general and in relation to specific islands, and to identify sites of high conservation value. His report leads into a set of s recommendations for further action. 1.3 These two reports, compiled during 1987, are complementary. Being produced independently, they empasise different aspects of the same question and differ for methodological reasons, in points of detail (see appendix 1) but come together to produce a clear overall picture from which conclusions may be drawn. Information on specific sites may be taken from the maps and reports but the results of these two parallel pieces of work are synthesised here to emphasise the salient points and provide a summary. Recommendations are also given- these do not replace those given by Mr Strange but present the general approach the Foundation would wish to espouse on the information contained in the reports. 2. Overall trends in tussac cover. 2.1.1 Tussac is in continuing decline in the Falklands. From an estimated original area : of c.22,200 Ha. of which c.9,900 Ha. lay on the coasts of East and West Falkland, : some 4-5000 Ha. of full tussac cover remains today. A mere 65 Ha. of that occurs on the two main islands. Important reductions in area have taken place in the past decade. J 2.1.2 Tussac is susceptible to degradation from natural causes but can recover when left undisturbed. Such natural causes include wear and tear from seals and I seabirds, and even occasional fire from lightning strike. Undisturbed tussac can also resist infection by 'rust' (Puccinia sp.). J 2.2 Recovery from fire may nevertheless take many years and improved means of 'i transport make tussac sites more accessible, increasing the risk of accidental burning. Out of 11 fires breaking out over the past 38 years, eight are attributable to human error (see Strange report). Fire is a major hazard, reducing the quality and quantity of tussac cover present at any given time and assuming an ever-increasing importance as the total tussac area decreases. Every effort must be made to reduce this risk. However, the main factor causing long-term decline of tussac is over-grazing. 1 j 5.2.2 Accepting that the foregoing recommendation will take time to implement and that 3. Grazing and Tussac. close management of tussac may not be possible in all cases, to take immediate action to conserve tussac wherever feasible. 3.1.1 Grazing converts dense tussac into open cover. ^Y^mnles^o^this 5.3 The following recommendations relate to the conservation of tussac stands. 5.3.1 Discontinue lease arrangements on Crown Land carrying tussac. the introduced guanaco population. 5.3.2 Take immediate action to secure pristine sites and other islands of high conservation value identified in this survey (see appendix 2) that are not already 3.1.2 Tussac can recover if grazing ceases. The process varies from islandI to island afforded conservation status. The manner in which these sites are secured for but Steeple Jason has shown a 40 Ha. increase in dense tussac since conservation will depend upon circumstances and may vary from site to site. removal of sheep in 1968 and other islands have also shown increases in overall tussac cover. 5.3.3 Develop a ground survey of sites as a follow-up to Mr Strange's field observations, to provide detailed, standardised information. It is recognised that 3.1.3 Paddocks of tussac can, with careful management, support sustained seasonal extreme caution will be required in this undertaking to prevent disturbance and grazing. The island farms on Sea Lion, Carcass and West Point are remarkable avoid increased fire risk but the work remains a fundamental requirement. in this respect. It is also noteworthy that these farms can produce high yields ot Further refinements in the conservation programme may be made on the basis of wool per acre. It is likely, though, that tussac cannot regenerate whilst subject to the information obtained. grazing pressure. 5.3.4 Review the legislation relating to reserves and legislation, to underpin reserve 4. Conservation of tussac. establishment and management. 4.1.1 Sites carrying a mosaic of dense tussac and lower vegetation are as important as These recommendations should be regarded as one aspect of a broader based effort pure dense tussac stands for birds and probably more important for other groups, to secure protection of key conservation sites throughout the Falklands. including native plants. It is the larger islands that will display the greatest I ecological diversity and capacity to sustain viable populations of plants and animals. Small islands have a valuable role to play in tussac conservation but the premium is upon larger islands and not necessarily those covered in pure tussac. 4.1.2 A high proportion of tussac (26% in 1956) is on areas marked as Crown Land on the Ordnance Survey maps. Fifteen of the Crown Land islands are already government reserves. The remainder still include some important tussac sites. 4.1.3 Other highly important sites, both for tussac and by virtue of other ecological characteristics, are in private ownership. Eight are wildlife sanctuaries and over twenty are managed as private reserves. Others are not afforded any conservation status. 4.1.4 It is extremely probable that there are sites of high conservation value that are not yet known. : 5. Recommendations. 5.1 Careful consideration must be given to the identification of potential causes of fire I n in tussac sites, and to taking all necessary action to reduce the possibility of its breaking out. These actions could include legislation, management practices applied to specific sites, and promotion of public awareness on the risks of fire To err on the side of caution would be preferable to toleration of avoidable risks. i H 1 r j 5.2 Tussac management can successfully be incorporated into sheep-farming practice although the more widespread trend is exploitative . There is a strong i case for the elaboration of a code of practice for tussac management, backed bv i [ J legislation where necessary. Given the continuing decline of tussac the : following steps should be taken without delay: i 5.2.1 Detailed examination of the economics and practice of tussac r . j consultation with those individuals experienced in it, leading to TfdevelnnmJnt \ . and application of a code of practice. y 2 3 Si" r-j u1 1 L T APPENDIX 2 APPENDIX 1.