A LONG TERM ENVIRONMENTAL ENRICHMENT PROGRAMME FOR CAPTIVE ELEPHANTS A BEHAVIOURAL STUDY

Transcription

1 A LONG TERM ENVIRONMENTAL ENRICHMENT PROGRAMME FOR CAPTIVE ELEPHANTS A BEHAVIOURAL STUDY A STUDY TO DETERMINE THE EFFECT OF RABBIT GRAZING ON CALCAREOUS GRASSLAND SIAN THOMAS PROFESSIONAL TRAINING YEAR PAIGNTON ZOOLOGICAL GARDENS COMPLETED AS PART OF BSc BIOLOGY (HONS) DEGREE UNIVERSITY OF WALES CARDIFF

2 CONTENTS SECTION ONE -Paignton Zoological Gardens 1. History of the Zoo 2. Structure and Function of the Zoo 3. Role of Placement Students SECTION TWO A Long Term Environmental Enrichment Programme for Captive Elephants ABSTRACT INTRODUCTION 1. Elephants in the Wild 2. Elephants in Captivity 3. Environmental Enrichment 4. Paignton Zoo Elephants 5. History of Project 6. Aims of Project

3 MATERIALS AND METHODS 1. Daytime Recordings 2. Night time Recordings 3. Foot and Mouth Recordings RESULTS CONCLUSIONS SECTION THREE A Study to Determine the Effect of Rabbit Grazing on Calcareous Grassland ABSTRACT INTRODUCTION`

4 SECTION TWO A LONG TERM ENRICHMENT PROGRAMME FOR CAPTIVE ELEPHANTS Abstract Two female elephants, one African (Loxodonta africana) and one Asian (Elephas maximus), are held at Paignton Zoo Environmental Park. In September 1997 they were moved from their old enclosure and home of over 20 years, to a larger enclosure. A long term study of their behaviour has been conducted since just before the move until the present day. Both elephants have behaviour patterns of some concern Duchess (the African) tends to spend considerable time being totally inactive and Gay (the Asian) exhibits a typical head-weaving or swaying stereotypy. Shortly after their move to the new enclosure it was apparent that these behaviours had not improved as greatly as anticipated and an enrichment programme was initiated. This has evolved in complexity over the years and has resulted in a steady decline of the concerning behaviours along with an increase in active and investigative behaviour. The most recent results indicate that swaying and inactivity have been reduced to negligible levels during daytime and some progress has also been made at night time when the animals are locked inside. However, further work is still needed at night time and this remains a major enrichment challenge.

5 Introduction Restriction of space and a lack of natural stimuli can result in a variety of physical and psychological problems in captive animals. Elephants in particular can be affected to a great extent, due to their immense size, strength, intelligence and complex social structure. Restrictions of captivity can result in certain behaviours developing that would not normally be performed in a wild environment or at least not to the extent as they may be captivity. If these behaviours become highly repetitive they are known as stereotypies and assumed to be an indicator of suboptimal welfare. Environmental enrichment aims to reduce the occurrence of these abnormal behaviours by stimulating a wider range of wild-type behaviour patterns. According to Shepherdson, 1989; Chamove and Moodie, 1990 there are five main aims: Increase behavioural diversity Reduce the frequency of abnormal behaviour Increase the range or number of normal (i.e. wild) behaviour patterns Increase positive utilisation of the environment Increase the ability to cope with challenges in a more normal way If this can be achieved it is thought that the welfare of the animal has been enhanced. Another advantage of environmental enrichment particularly in a zoo environment is that it can educate members of the public allowing them to see more natural activities.

6 This project was established in 1997 in order to develop a long term enrichment programme for the two elephants held at Paignton Zoo. Elephants in the wild can spend up to sixteen hours a day walking in the search for food. This is prevented in captivity due to the restriction in space and food is usually presented straight to the animal removing the need to search for it. Therefore large periods of the day become unoccupied. Many enrichment methods have been formally evaluated for their effectiveness in reducing abnormal behaviour and increasing foraging, feeding and exploration behaviour of the elephants. Successful methods have been incorporated into a programme of enrichment now in its fifth year. Specific aims Reduce the time spent swaying by the Asian Elephant Reduce the time spent completely inactive by the African Elephant Increase investigative, exploratory, foraging and feeding behaviour of both elephants Methods Subjects Paignton Zoo holds two female elephants, one African (Loxodonta africana) and one Asian (Elephas maximus). Duchess, the African is approximately 33 years old and Gay the Asian roughly a year younger. They arrived together at Paignton from Longleat Safari Park in Duchess is the more dominant of the two and exhibits

7 more behaviour indicative of having the matriarchal role within this small herd. She is very food orientated and shows little curiosity in novel items unless they contain food. Prior to the initiation of the enrichment programme she spent a large proportion of the day being totally inactive. This time was much greater than has ever been observed in wild elephants and was therefore of some concern. Gay is much more playful than Duchess and spends more time interacting with non-food related objects. Prior to enrichment she spent considerable time performing a typical head weaving or swaying stereotypy. Enclosure In September 1997 the elephants were moved from the enclosure that had been their home for 20 years to a new exhibit at the other side of the zoo. In contrast to their old enclosure which was concrete, with a small house and few furnishings their new home included a large indoor area, a much larger sandy paddock, a wallow and several scratching posts. In the old enclosure they had frequent contact with the public across a dry moat. Following the move this contact was no longer possible for their own and the public s safety. Human contact is limited to experienced keepers and occasional protected contact with other staff or special visitors. Enrichment Enrichment methods were designed to stimulate species specific behaviour (for example a small ball feeder designed for monkeys would be pointless for elephants). They had to be either disposable or extremely strong. Hygiene and safety if items did break also had to be considered. Individual differences were also taken into account in

8 the design of enrichment since Duchess rarely responded to any items not involving food but Gay did. A list of enrichments divided into chronological phases is shown in Table 1. The phases generally correspond to observation periods carried out by successive sandwich placement students and items in phases 1-4 have been described previously (Angele 1999, Angele et al. 2001; Gloyns 2000a and b). Enirchment devices utilised during phase 5 included flour and water logs, kerplunk and inside feeder logs. The flour and water logs were large logs previously stripped of bark by the elephabts, covered in flour and water paste and rolled in dry feed (seeds, flakes etc). The elephants would spend a long time picking the feed off the logs using their trunks. Once the dry feed was removed, they would then spend long periods removing the dried flour and water paste in the same way that they would strip bark off a log. Kerplunk was based on the children s game of that name and consisted of a large suspended barrel with fresh bamboo inserted through holes in the sides. Small amounts of fruit and vegetables were held inside the barrel by the bamboo and the elephants would remove (and eat) the bamboo until the fruit fell out. Inside Feeder logs are very large logs with numerous holes drilled into the side. These holes were then filled with fruit or vegetables and the elephants had to pick it out using their trunks. The original design was made using much smaller logs that the elephants could pick up. This resulted in the logs being emptied of food rapidly as the elephants soon learnt that by throwing the log on the floor all of the food fell out. A much larger log was then used which they could only roll, not pick up. This allowed the enrichment device to last a for a much longer period of time as the elephants had

9 to manipulate the food using their trunks. Other enrichments added this year are self explanatory. Table 1. Implementation phases of an increasing complex enrichment programme for elephants at Paignton Zoo Environmental Park. PHASE ENRICHMENT DEVICES 1 Scatter feed Daily food hidden in pipes/boxes and buried 2 Suspended barrels of dry feed (small holes in bottom of barrel) Suspended logs for bark stripping Brambles wrapped around branches (provides browse in winter) 3 Hanging pipe feeders Two tyre feeder Tyre and chain rattle Deep earth container 4 Scratching post Rattles and wind chimes Hanging tyre New hanging barrels 5 Giant ice blocks Squashed barrel (filled with dry feed) Flour and water logs

10 Inside feeder log Mini kerplunk Bamboo kerplunk Hay racks installed at full stretching distance Scents New log pile Phase 1: Enrichment designed and implemented by Natalie Barber, 1998 Phase 2: Continuation of enrichment by Natalie Barber Phase 3: Enrichment designed and implemented by Catalena Angele, 1999 Phase 4: Enrichment designed and implemented by Rosie Gloyns, 2000 Phase 5: Enrichment carried out by myself NB: Any pre-enrichment data was carried out by Andy Marshall in 1997 immediately after the elephants moved to the new enclosure. Observations Instantaneous focal sampling was used to record the data. Observations were carried out at minute intervals for half hour periods. For each condition data was collected so that each hour between the times of 8am and 5pm were covered. No more than two hours were recorded in any one day and the half hour periods were chosen randomly. An extensive ethogram has been developed with a number of behavioural codes for ease of recording. (See Appendix??) However for the purposes of the enrichment evaluation certain behaviours were placed into three categories:

11 1. Investigative Behaviours (IB) - all investigative and exploratory behaviour including foraging and feeding are combined. 2. Inactiviy/Swaying (In/Sw) these are the focal behaviours for the two elephants (Inactivity for Duchess and Swaying for Gay). 3. Interacting with Enrichment Devices (ED) this includes any interaction with a device whether it had been just placed in the enclosure or whether it had been in place for a long period of time. (i.e. any involvement with the hanging barrels was noted whether they contained food or not). As new enrichment methods are found to be successful they are incorporated into the timetable. To avoid having to remove all enrichment for a time, new phases of enrichment are tested against the existing timetable rather than against a noenrichment baseline. Due to practical difficulties there have been two periods of the programme when no new enrichment methods were added for several months. These periods have been termed baseline but they are not baseline in the strict sense since the existing enrichment items were still being provided. Kruskal-Wallis tests on daily mean times spent performing the behaviour types of interest have been used to compare the different phases of the programme. Results Since its initiation the enrichment programme has resulted in a steady decrease in time spent inactive by Duchess (Fig. 1) from approximately 22% to around 4% of the day (P < 0.01). Inactivity increased to some extent during the two periods (baselines 4 and 5) when no new enrichment was added for several months but did not return to the levels seen before the programme started.

12 Fig. 1 Mean daily time spent on investigative and foraging behaviour and inactive by the African elephant Duchess during increasingly complex phases of an enrichment programme. Error bars are standard error Interactive Behaviours Inactivity % Time Pre-enrich Phase 1 Phase 2 Phase 3 Baseline 4 Phase 4 Baseline 5 Phase 5 Enrichment has also resulted in a dramatic decline in time spent swaying by Gay during the day (Fig. 2) from 24% to less than 1% (P < 0.01). During baseline 4 and 5 when no new enrichment was added this figure did rise slightly but to nowhere near the levels observed initially. Swaying by Gay during the day is now only observed to happen when the gate between the outside and inside enclosures are locked preventing her from choosing where she wants to be. This appears to cause either frustration or anxiety and usually results in swaying in front of the gate.

13 Foraging and exploratory behaviours do not appear to be greatly affected by enrichment but these figures do not include and interactions with the enrichment devices themselves. These times are shown in figs. 3 and 4 for the baseline 5 and phase 5 (datasets for 2001) and it can be seen that they are quite substantial, in Phase 5 over 30% for Duchess (fig. 3) and over 40% for Gay (fig. 4). Total foraging and exploration including interacting with enrichment has therefore steadily increased throughout the programme. Fig. 2 Mean daily time spent on investigative and foraging behaviour and swaying by the Asian elephant Gay during increasingly complex phases of an enrichment programme. Error bars are standard error Interactive Behaviours Swaying % Time Pre-enrich Phase 1 Phase 2 Phase 3 Baseline 4 Phase 4 Baseline 5 Phase 5

14 Fig. 3. Mean daily time spent performing three behaviour types by an African elephant, Duchess, during baseline 5 (existing enrichment not changed for several months) and Phase 5 (new enrichments added) of an enrichment programme Baseline Treatment Percentage Time Investigative Behviours Inactivity Enrichment Device Behaviour Group Fig. 4. Mean daily time spent performing three behaviour types by an Asian elephant, Gay, during baseline 5 (existing enrichment not changed for several months) and Phase 5 (new enrichments added) of an enrichment programme Baseline Treatment Percentage Time Investigative Behviours Swaying Enrichment Device Behaviour Group

15 FOOT AND MOUTH DISEASE During the foot and mouth crisis the elephants were put into quarantine for a number of weeks. At one point they were actually locked in the inside enclosure and had no physical contact with anyone, including the keepers. This appears to have had negative affects on the behaviour of both animals. Gay appeared to sway for most of the day and Duchess became more impatient and aggressive. At this time only essential staff only were allowed into the zoo and no formal behavioural observation was performed. This strict quarantine was discontinued after a short time due to these behavioural problems and the elephants were again allowed outside. However for several more weeks no enrichment items were allowed to be placed in the enclosure and data was collected during this period. This has allowed us to generate a true return to baseline pre-enrichment conditions. Night time enrichment Although we have managed to reduce Gay s swaying to a very small amount during the day it was thought there may still be a problem at night. Therefore data has been collected at night to determine the extent of the problem and an enrichment programme has been established to reduce her swaying at this time. Night time baseline data indicate that there is little cause for concern for Duchess (fig. 5), she spends much of the night asleep or foraging for and eating hay. However Gay spends considerable time at night swaying (fig. 6). This tends to occur in the first two hours after the keepers leave and again for an hour or so before the arrive back in the morning. Gay also sways whenever Duchess lies down to sleep. Enirchment methods have been instigated to reduce swaying at the beginning and end of the night but to

16 date we have not found a solution to swaying when Duchess lies down. Data for the effects of night enrichment is currently being analysed. Fig. 5 Proportion of time spent performing various behaviours by an African Eating Hay Foraging Sleeping Standing Other elephant Duchess during the night. Fig. 6 Proportion of time spent performing various behaviours by an Asian elephant Eating hay Foraging Sleeping Swaying Other Gay during the night.

17 Conclusions Enrichment does work, even for elephants. Swaying and inactivity have been reduced to minimal levels during the daytime indicating an improvement in welfare of both animals More night time enrichment is needed to reduce swaying by the Asian elephant. Habituation to existing enrichment is a problem and new items are continually needed to maintain stimulation References Angele, C Assessing the Effectiveness of Environmental Enrichment for Elephants at Paignton Zoo A Behavioural Study. Professional Training Report. School of Biological Sciences, Cardiff University. Angele C. Barber N. & Plowman A.B Elephant enrichment at Paignton Zoo. Proceedings of the 4th International Conference on Environmental Enrichment, Edinburgh In press Chamove & Moodie Are alarming events good for captive monkeys? Applied Animal Behaviour Science 27: Gloyns, R. 2000a. Environmental Enrichment for Elephants at Paignton Zoo - A Behavioural Study. Professional Training Report, School of Biological Sciences, Cardiff University. Gloyns, R. 2000b. Long-term enrichment for captive elephants. Proceedings of the 2nd Annual Symposium on Zoo Research. Ed. A. B. Plowman. Federation of

18 Zoological Gardens of Great Britain and Ireland/Paignton Zoo Environmental Park. Pp Shepherdson, D Improving animal lives in captivity through environmental enrichment. Euroniche Conference Proceedings. Eds F. Dolins and G. Mason Humane Education Centre, London. Pp

19 An Investigation to Determine the Effects of Rabbit Grazing on an Area of Introduction Calcareous Grassland In low rainfall areas of the world, grasslands are a common feature and one of the most widespread vegetation types. However, these grasslands are rapidly reducing. This is mainly due to the influence of man or where grazing is absent, natural succession to scrub. This loss is particularly great for calcareous grasslands.(duffey, 1974). Grassland communities in Britain can be classified into three categories: 1. Calcareous Grasslands 2. Neutral Grasslands 3. Acidic Grasslands Calcareous grasslands are formed in regions of high calcium carbonate. The main types of limestones that they occur on are: 1. Cretaceous Chalk 2. Oolitic (Jurassic) Limestone 3. Carboniferous or Mountain Limestone 4. Magnesium Rich Limestone (Duffey, 1974)

20 Grazing animals are common throughout Britain and have major effects on plant communities. The Normans introduced the European Rabbit (Oryctolagus cuniculus) to Britain in the twelfth centuary from the Mediterranean. Originally they were kept and bred simply for fur and meat. Today they can be found in a variety of habitats across Britain but prefer areas that allow easy burrowing and an accessible food supply. The diet consists of a range of plants including grasses, cereal crops, root vegetables and young shoots of meadow plants. (Gorman, M.L.). In the middle of the nineteenth century numbers started to increase dramatically until they began to be considered as agricultural pests. The breeding season is mainly from January to August, starting later in the North of Britain. Healthy females can produce one litter of 3-7 young per month during the season. This therefore means that a large number of rabbits can be born in a year. The rapid increase was also due to a large number of hedgerows that were planted due to new enclosure acts. This provided ideal habitats for the rabbits as burrowing improved due to loosened soil and provided shelter. Advances in agricultural technology also meant an improvement in the production of cereal crops increasing the food supply available to the rabbits. Another factor that played a role in the increase in numbers of the rabbits was that a large number of their natural predators were killed by the formation of hunting estates. (Gorman, M.L.). Myxomatosis occurred in Britain in the 1950s which was very successful in reducing the numbers. However, this rapid decline in numbers caused major changes in natural vegetation as the amount of grazing was dramatically reduced (Bhadresa, R. 1987

21 cited Sheail, 1971) This allowed natural succession of grasslands and other areas to scrubland affecting the species composition and removing rare species due to competition. After the initial epidemic of myxomatosis the national population of rabbits started to increase gradually again and numbers at present are high once again. Grazing may eliminate species from an area in two ways: 1. Outright removal of all plants 2. Lowering the density of plants to such a level that any individuals that remain exist in such a low distribution that it is impossible to sustain a self-replacing population hence the removal of the species. (Silvertown, J.W., 1982 cited Carter and Prince, 1981) Vegetation may be defined as an assemblage of plants growing together in a particular location and may be characterised either by its component species or by the combination of structural and functional characters. (Goldsmith et al, 1986) There are different methods of studying vegetation. Structural or physiognomic methods do not require individual species to be identified. Zoologists therefore often prefer these methods as they are more meaningful for small-scale studies and for habitat descriptions. For studies such as this one, methods based on species composition or floristics are more valuable as they are more detailed and botanical in nature.

22 There are different measures based on floristics which can be classified into two categories: 1. DESTRUCTIVE MEASURES Fresh weight and dry weight are the two most commonly used measures. Fresh weight has the disadvantage that moisture content varies within plants which would affect the results. These measures however are not being used in this project due to the fact that there are many species on the grassland that are considered rare. 2. NON-DESTRUCTIVE MEASURES Site Description The area of grassland studied is situated within an area of land known as Clennon Gorge. Clennon Gorge is approximately 60acres and stretches down to the sea between Paignton and Goodrington in South Devon. The land on which the grassland is situated is owned by Paignton Zoo but access to the public is denied. The site is predominately on carboniferous limestone which forms a plateau on the eastern side of the valley. The grassland is position on this plateau and shows the characteristic flora of calcareous grassland. The grassland and surrounding woodland provide a suitable habitat for rabbits and other small mammals. In 19?? four small exclosures were established. The

23 exclosures are generally rectangular in shape constructed from wire mesh approximately 50cm high. For the purpose of this study only two of the four exlosures will be studied. One of the exclosures was deemed to be situated too far into the woodland to be statistically comparable as other factors would be influencing the diversity and the other the largest of the four is situated in the area that is virtually entirely scrub land. It is also surrounded by trees which creates a large amount of shade affecting the microclimate and making it more humid. This therefore provides different conditions and therefore different species would thrive. Due to this and the fact that this exclosure is so much larger than the others it was decided to dismiss this exclosure. This left two exclosures suitable for comparison. Exclosure One is situated on the lower part of the grassland whereas Exclosure 2 is situated on the higher level. Exclosure One 5.30m 5.00m 4.95m 4.90m 4.95m 4.60m 5.05m Exclosure Two 4.65m

24 Due to the variation in size and shape of the exclosures it was decided that a 4m x 4m plot should be taped off inside the exclosures. Not only does this allow for accurate statistical analysis it also reduces any edge effects that may occur. Each exclosure however is slightly different. Exclosure one only managed to partially exclude the rabbits. Evidence of rabbit dropping was discovered within the exclosure and two holes were found within the fencing. These holes were repaired and therefore this exclosure is deemed as a partial exclusion zone. Exclosure one is also in the shade until around 11.30am whereas Emilly is in direct sunlight for the entire day. Aims To determine: 1. Is there a difference in species composition in different areas of the grassland? (i) open grassland (ii) rabbit exclosures 2. Is there a particular species of plant that is preferred by the rabbits?

25 3. Is there a particular species of plant that is dominant due to the effect of the grazing (ie is there a plant that thrives due to the fact that other species have been removed by the rabbits)? 4. Are there any other factors apart from rabbit grazing that may affect the composition? 5. Does the height of plants vary between the grazed area and the exclosures? 6. Are there any differences between the two exclosures?

26 Method Grazed Area The presence of species in 50cm x 50cm quadrats located at 0.5m intervals along 2 parallel straight lines. At least 100 quadrats to be recorded. (50 on each transect) Exclosures Tape off a 4mx 4m so that all three sampling areas are the same size and shape and to reduce edge effects. Random quadrat sampling so that at least 50 quadrats are recorded. Within each quadrat a number of factors will be assessed: Species present Maximum height of vegetation Species diversity (ie a pin will be placed in the centre of the quadrat and any species touching that pin will be recorded as well as the heights of those species). Within each exclosure other factors will also be recorded: Depth of Soil ph