The proposed Parc Regional de Belomotse - Frontier-publications ...

More documents

Recommendations

Info

Line transect methods have been developed for estimating the density of primates in continuous forest and have not been adapted for fragmented habitats such as those found within the survey area. However, the survey team spent long periods of time in each area, allowing for repeated observations of the lemur groups. Therefore, total counts of both species were also estimated from these direct observations. 7.3 Results The survey revealed populations of Propithecus verreauxi verreauxi and Lemur catta in all of the three surveyed areas (see table 5). 7.3.1 Line transects Assessments of lemur population numbers using line transects identified high numbers of ring-tailed lemurs around Antafoky Lake and along the corridor of forest between the lake and the Sept Lacs region, with a comparably lower number within the Sept Lacs region. The density of ring-tailed lemurs appeared to be highest around Antafoky Lake. A comparable pattern was observed for Verreaux’s sifaka, with high numbers around Antafoky Lake and along the forest corridor, and comparatively lower numbers within the Sept Lacs region. The density of sifaka appeared to be considerably greater around Antafoky Lake than at the other two sites. 7.3.2 Direct observation Assessments of ring-tailed lemur populations by direct observation identified high population numbers around Antafoky Lake and along the forest corridor, with lower numbers within the Sept Lacs region. The density of ring-tailed lemurs appeared to be slightly higher around Antafoky Lake. A similar pattern was observed with Verreaux’s sifaka, with high numbers observed around Antafoky Lake. The density of sifaka appeared to be greater around Antafoky Lake than at the other two sites. Table 5. Minimum numbers and density of diurnal lemurs at three locations within the survey area, using two different methods. Lemur catta Area of gallery forest Min. No. by direct count Density (No. / ha.) by direct count Min. No. by line transect Density (No. / ha.) by line transect Antafoky Lake 140 ha. 138 1 299 2.1 Sept Lacs 110 ha. 75 0.7 158 1.4 Corridor 220 ha. 150 0.7 260 1.2 P. v. verreauxi Antafoky Lake 140 ha. 42 0.3 110 0.8 Sept Lacs 110 ha. 25 0.2 17 0.2 Corridor 220 ha. 25 0.1 52 0.2 34
7.4 Discussion 7.4.1 Comparison of methods The two lemur density assessment methods produced very different results. The direct observation method obtained results through repeated sightings and countings, and gave a minimum figure for the number of individuals present within the surveyed areas. However, it is probable that not all groups and individuals were observed and counted. Conversely, the line transect method produced much higher figures for lemur numbers and densities than the direct observations, in some cases the estimates were over twice as high. Based on the relative accuracy of repeated counts based on direct observations within fairly small areas of forest, the estimates produced by the line transects appear to be too high. The areas of gallery forest surveyed were fairly narrow and a large field team spent a long period of time in each survey area. The presence of such large numbers of diurnal lemurs would have been observed during direct observations. The actual number of individuals for each of the diurnal lemur species is probably closest to the figures given by direct observation. Previous surveys within similar areas and habitats have shown that the line transect method is difficult to apply, and that counts based on direct observations have been found to be more accurate (J. Durbin, pers. comm., 2002). 7.4.2 Lemur density and distribution The areas of gallery forest differ considerably in size between the three surveyed areas (see Table 5). This appears to have been reflected in the numbers and densities of lemurs that were observed in these habitats. High densities of both diurnal lemur species were estimated for the area of forest around Antafoky Lake where, despite recent forest clearance for crop cultivation, the forest is both large and fairly undisturbed. With an estimated area of approximately 140 ha, this is the single largest fragment of gallery forest within the proposed park area. The corridor of gallery forest contained fairly high numbers of P. verreauxi verrauxi and very high numbers of L. catta. However, the density of lemurs was low. The combined areas of gal1ery forest along this corridor were estimated to be approximately 220 ha in size, although the quality of the forest varied considerably. The small tributary valleys contained some areas of relatively undisturbed forest, whereas the gallery forest that bordered the river was narrow, fragmented and extremely degraded in some areas. It appears that this fragmentation to the gallery forest along the corridor, combined with the fairly high levels of degradation in some areas, may have led to the comparatively low lemur densities that were observed. Low numbers of both diurnal lemur species were recorded within the Sept Lacs region. However, the densities of both species were comparatively high. The forest was less disturbed than the corridor area but only covered approximately 110 ha in a narrow band along the Ifanato River. This may have adversely affected lemur density. However, several other factors should be taken into account, such as plant species composition and detection bias (lemurs could not be heard over the sound of the 35
Page 1 and 2: Frontier Madagascar Environmental R
Page 3 and 4: Suggested Technical Paper citation:
Page 5 and 6: Contents List of Figures List of Ta
Page 7 and 8: 10.1 Introduction 46 10.2 Methods 4
Page 9 and 10: List of Figures Figure 1: Figure 2:
Page 11 and 12: EXECUTIVE SUMMARY This report descr
Page 13 and 14: ACKNOWLEDGEMENTS This summary repor
Page 15 and 16: 1. Introduction 1.1 Madagascar Mada
Page 17 and 18: 1.3 Threats to Conservation The hig
Page 19 and 20: collected by the WWF-Madagascar Dry
Page 21 and 22: initiative. This regional departmen
Page 23 and 24: 3. The Study sites Work was carried
Page 25 and 26: The trapsites were positioned such
Page 27 and 28: 4. Plants 4.1 Introduction The Mala
Page 29 and 30: Table 3. The number and endemism of
Page 31 and 32: These results seem to show that the
Page 33 and 34: 5. Mammals 5.1 Introduction Mammals
Page 35 and 36: madagascariensis and the Barn Owl,
Page 37 and 38: 5.3.3 Observations, tracks and call
Page 39 and 40: Cheirogaleus medius, the Coquerel
Page 41 and 42: However, only two year-round trappi
Page 43 and 44: In many areas, species are hunted f
Page 45 and 46: 6.4 Discussion 6.4.1 Temporal varia
Page 47: 7.2 Methods Between May and August
Page 51 and 52: threatened. Several species, includ
Page 53 and 54: Nine species were observed solely i
Page 55 and 56: 9.3 Results A total of fifty-five d
Page 57 and 58: areas, all of them were found in th
Page 59 and 60: 9.4.5 Range extensions and locality
Page 61 and 62: 10.2 Methods Amphibians were observ
Page 63 and 64: the associated riparian forest, the
Page 65 and 66: knowledge, are linked solely to rip
Page 67 and 68: 11.2 Malaise Trapping 11.2.1 Introd
Page 69 and 70: The genus Cerapachys is rarely foun
Page 71 and 72: 11.5 Molluscs and Millipedes 11.5.1
Page 73 and 74: 12. Resource use and Socio economic
Page 75 and 76: 12.3 Results 12.3.1 Biological dive
Page 77 and 78: Reeds are collected from the shallo
Page 79 and 80: egion’. The development of the re
Page 81 and 82: oat or on foot. From the lake, the
Page 83 and 84: Figure 10. The approximate position
Page 85 and 86: the development of tourism and asso
Page 87 and 88: References Billé, R. & Mermet, L.
Page 89 and 90: Lundahl, S. L. L. & Olsson, A. 2000
Page 91 and 92: Appendix 1. Trapsite (TS) Habitat D
Page 93 and 94: Ground layer < 10 %, scrub layer 10
Page 95 and 96: Appendix 2. Continued. FABACEAE Rob
Page 97 and 98: Appendix 3. Numbers of individuals
Page 99 and 100:
Appendix 3. Continued. LOGANIACEAE
Page 101 and 102:
Appendix 4. Plant numbers and speci
Page 103 and 104:
Appendix 6. List of mammal species
Page 105 and 106:
Appendix 7. Continued. 42 Centropus
Page 107 and 108:
Appendix 9. List of reptile species
Page 109 and 110:
Appendix 10. List of butterfly spec
Page 111 and 112:
Appendix 11. Descriptions of Sugges
Page 113 and 114:
Ring-tailed lemurs and Verreaux’s
Page 115 and 116:
Hide 3 Surroundings - Located in ga
Page 117:
Appendix 13. Specimen identificatio
show all

The proposed Parc Regional de Belomotse - Frontier-publications ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?