2.                  INSECTS, HERPETOFAUNA AND MAMMALS IN LOK MA CHAU

 

2.1              Introduction

 

2.1.1        Field visits were undertaken in June, July, August, September, October and November 2000, and were then suspended for four months before being resumed in April and May 2001. Between December and March insect and herpetofauna activity is very low and it was considered unnecessary to continue surveys during this period. Following preliminary site visits, 5 formal transect routes were established. These transects were used for both insect and herpetofauna surveys, and are located near to, but not on, the development footprint (see Figure 2).

 

2.2              Methodology

 

Insects

 

2.2.1        Insects (dragonflies and butterflies) were surveyed on two mornings per month, on fine weather days. Transects were walked at a fixed pace and all individuals observed along or on either side of the transect (within a radius of approximately 5m) were identified, sexed (where possible) and counted. Care was required to ensure that individuals were not counted more than once. Some dragonfly males, in particular, have the habit of patrolling back and forth along a fixed territory, and may therefore be encountered on several occasions during the same transect walk. To complement transect surveys, general surveys of the whole site were made.

 

2.2.2        Field equipment consisted of close-focusing binoculars to aid identification of small, distant or evasive species, and a long-handled collecting net in case of encounters with species which require examination in the hand (on-site) or, in the case of problematic specimens, temporary collection for later identification.

 

Herpetofauna

 

2.2.3        Herpetofauna (reptiles and amphibians) were surveyed on two afternoons per month, on fine weather days. The same transects as used in the insect surveys were followed and all individuals observed were identified, sexed (where possible/appropriate) and counted. Active searching of suitable microhabitats along the transects (e.g. huts, stones or wooden boards on the ground, tree trunks and other upright structures, small water impoundments, etc.), and pauses to wait for re-emergence of glimpsed animals, meant that it was not possible to sustain a fixed pace during herpetofauna surveys. To complement transect surveys, general surveys of the whole site were made. This procedure was repeated on two evenings per month, during which identifications were made by torchlight and/or, in the case of breeding amphibians, by auditory detection.

 

Mammals

 

2.2.4        No specific mammal surveys were carried out. However, any mammals or mammal signs (such as scats) observed during the course of other surveys were recorded.

 

Transect

 

T1.       Located along the border road and situated along the northern bunds of the two unnumbered ponds lying immediately to the east of the border crossing road, north of Ha Wan Tsuen.

 

T2.       Commencing at the northeast corner of pond 52 and continuing southwards along the western bank of pond 51.

 

T3.       Located along the border road and situated along the northern bunds of pond 28 and the unnumbered pond lying to its immediate northeast.

 

T4.       Located along the border road and situated along the northern bunds of ponds 2 and 6.

 

T5.       Commencing at the southern bund of pond 55 and continuing southwards to the southern end of the bund lying between ponds 56 and 61.

 

2.3              Results - Transect Surveys

 

Dragonflies - Result

 

2.3.1        Tables (2.1 - 2.5) showing results of transect surveys are given below. Graphs showing abundance of particular species are given in Appendix C.

 

Table 2.1 Dragonflies at transect 1

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Brachythemis contaminata

13'5"

10'2"

7'1"

8'3"

1'

4'

2'

4'2"

5'

4'1"

2’

1’

3’1”

 

9’3”

4’1”

Crocothemis servilia

 

 

2'

 

1'

1'

 

 

 

 

 

 

 

 

 

 

Ictinogomphus pertinax

2'

1'

3'

2'

3'

 

1'

1'

 

 

 

 

 

 

 

1’

Ischnura senegalensis

4

11

3

21

8

9

2

9

5

2

 

 

 

 

4

6

Orthetrum sabina

8

6

5

4

3

7

3

3

1

1

2

2

 

 

3

2

Pantala flavescens

 

13

5

 

7

10

3

 

6

 

2

 

2

 

 

 

Rhyothemis variegata

3

8

3

5

5

2

 

4

 

2

 

1

 

 

14

2

Tramea virginia

 

 

 

 

2'

 

 

1

1

 

 

 

1

1

 

 

No. of species

5

6

7

5

8

6

5

6

5

4

3

3

3

1

4

5

Abundance

35

51

29

43

30

33

11

24

18

10

6

4

7

1

33

16

 

' male; " female

 

Table 2.2 Dragonflies at transect 2

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Anax guttatus

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1’

 

Brachythemis contaminata

3'1"

5'4"

3'4"

2'

5'8"

8'4"

3'

1'

 

1'

1’

 

5’2”

5’3”

3’4”

3’

Ceriagrion auranticum

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

Crocothemis servilia

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2’

Diplacodes trivialis

 

 

 

1'

 

 

1'

 

 

 

1’

 

 

 

 

 

Orthetrum sabina

 

1

3

1

1

2

 

2

 

1

 

 

 

1

9

2

Ischnura senegalensis

 

 

 

 

 

 

 

 

 

 

2’

1’

 

4’1”

2’3”

1’1”

Pantala flavescens

3

 

8

3

 

4

1

5

3

2

 

 

1

2

 

 

Rhyothemis variegata

3

6

8

4

10

 

3

5

2

 

 

 

4

3

8

6

Tramea virginia

 

 

 

 

 

 

 

 

 

 

 

 

 

2

1

1

No. of species

3

3

5

5

3

3

4

4

2

3

3

1

3

6

6

6

Abundance

10

16

32

16

24

18

8

13

5

4

4

1

12

21

31

16

 

' male; " female

 

 

Table 2.3 Dragonflies at transect 3

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Brachythemis contaminata

 

 

4'1"

2'

2'

 

2'

 

 

 

3’

 

 

5’2”

6’6”

4’1”

Crocothemis servilia

 

1'

 

1'

2"

 

 

 

 

 

 

 

 

 

 

 

Ictinogomphus pertinax

 

2'

1'

 

1'

1'

 

 

 

 

 

 

 

2

 

1

Ischnura senegalensis

13

8

4

19

5

7

 

5

2

 

 

 

10

4

6

8

Orthetrum sabina

1

1

4

3

5

6

2

3

1

2

1

2

1

4

3

3

Pantala flavescens

2

12

15

4

 

3

8

1

9

2

 

2

 

 

 

 

Rhyothemis variegata

1

24

 

6

10

2

 

8

 

 

1

1

 

9

3

3

Tramea virginia

 

 

1

2

2

 

 

 

 

 

 

 

 

1

2

2

No. of species

4

6

6

7

7

5

3

4

3

2

3

3

2

6

5

6

Abundance

17

50

30

37

27

19

12

17

12

4

5

5

11

27

26

22

 

' male; " female

 

Table 2.4 Dragonflies at transect 4

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Brachythemis contaminata

 

2'

1'

 

1'

 

4'

 

 

 

 

 

2’

3’

3’2”

2’2”

Crocothemis servilia

 

 

 

 

1'

 

 

 

 

 

 

 

 

 

 

 

Hydrobasileus croceus

1

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

Ictinogomphus pertinax

 

 

 

1'

1'

 

1'

 

 

 

 

 

 

1’

 

2’

Ischnura senegalensis

4

 

5

 

 

 

7

3

 

1

 

 

3

2

2

20

Orthetrum sabina

3

 

3

1

1

 

3

4

2

2

2

1

 

1

2

4

Pantala flavescens

5

2

10

 

1

13

5

2

7

4

1

 

8

 

2

1

Rhyothemis variegata

 

2

4

 

15

1

 

5

2

 

1

 

2

3

 

17

Tramea virginia

2

 

 

 

1

 

 

 

 

 

 

1

 

 

 

 

No. of species

5

3

5

2

8

2

5

4

3

3

3

2

4

5

4

6

Abundance

15

6

23

2

22

14

20

14

11

7

4

2

15

10

11

48

 

' male; " female

 

Table 2.5 Dragonflies at transect 5

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Brachythemis contaminata

3'1"

4'

1'

 

1'

2'

 

1'

 

 

 

 

 

 

 

 

Crocothemis servilia

 

 

 

 

1'

 

 

 

 

 

 

 

 

 

 

 

Epopthalmia elegans

 

1'

 

 

2'

1'

 

 

 

 

 

 

 

 

 

 

Ictinogomphus pertinax

1'

2'

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ischnura senegalensis

3

17

9

5

5

 

8

7

1

 

 

 

 

 

 

 

Orthetrum sabina

5

3

5

1

4

1

3

3

 

1

 

 

 

 

 

 

Pantala flavescens

7

4

7

6

2

8

 

2

6

4

1

 

2

 

2

2

Rhyothemis variegata

 

 

 

 

1

 

 

3

 

 

 

 

 

 

 

 

Sinictinogomphus clavatus

 

 

 

 

 

1'

1'

 

 

 

 

 

 

 

 

1’

Tramea virginia

2

 

 

1

 

 

 

 

 

 

 

 

 

 

 

1

No. of species

5

6

4

4

7

5

3

5

2

2

1

0

1

0

1

3

Abundance

22

31

22

13

16

13

12

16

7

5

1

0

2

0

2

4

 

' male; " female

 

 

2.3.2        Notable dragonfly sightings made close to but just outside of the transects (i.e. of species not otherwise recorded) included the following:

 

Anax guttatus - 1 individual seen at pond 3 on 12 August. A common species locally (Wilson, 1997).

 

Orthetrum glaucum - 1 male seen on road beside pond 53 on 25 July.

 

Orthetrum pruinosum - 1 male on road beside pond 53 on 25 July; 1 male on road beside pond 51 on 12 August. Both species abundant locally (Wilson, 1997).

 

Table 2.6

Summary of Dragonfly Diversity and Abundance for Transects

 

 

T1

T2

T3

T4

T5

Mean no. spp. per visit

4.75

3.75

4.5

4

3.06

Mean dragonfly abundance per visit

21.94

14.44

20.06

14

10.38

Total no. of species

8

10

8

9

10

 

Discussion

 

2.3.3        The odonate fauna at Lok Ma Chau was typical for fish pond areas, with a small number of common species predominant. No species of conservation concern were recorded. The most notable records were those of Epopthalmia elegans and Sinosticta clavatus in pond 61 (transect 5). These large pond species were not seen anywhere else in the Lok Ma Chau study area. They are rated as 'fairly common' by Wilson (1997) but are not as frequently encountered as the similar-sized Ictinogomphus pertinax. Transects 2 and 5 had the highest overall number of dragonfly species (10), although average number of species per visit was lowest for these transects (Table 2.6). Conversely, transects 1 and 3 had the lowest overall number of species (8), but the highest mean number per visit (Table 2.6). Two common and widespread species, Pantala flavescens and Rhyothemis variegata, exhibit swarming behaviour and can be present in very large numbers.

 

2.3.4        It should be noted that the scheduling of the surveys was such that crepuscular or eocrepuscular species were under-recorded. At least three additional species (Anaciaeschna jaspidea, Tholymis tillarga and Zyxomma petiolatum) are likely to be present within the study area but were overlooked because they are primarily active at dawn and/or dusk. However, none of these species is of conservation significance in Hong Kong.

 

Butterflies

 

2.3.5        Results for all five transects are summarised in one table below (Table 2.7).

 

Table 2.7 Butterfly species recorded at transects

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

15.10

27.10

15.11

29.11

2.4.01

27.4

8.5

22.5

Ariadne ariadne

 

 

 

 

 

 

1(T2)

 

 

 

 

 

 

 

 

 

Athyma nefte

 

 

 

 

 

1(T5)

 

 

 

 

 

 

 

 

 

 

Catopsilia pomona

 

1(T3)

 

1(T1)

 

 

 

 

 

 

 

 

 

1(T1)

1(T4)

 

Danaus genutia

 

 

 

 

 

 

 

 

1(T1)

 

 

 

 

 

 

 

Delias pasithoe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1(T4)

Euploea core

 

 

 

 

1(T2)

 

1(T4)

 

 

 

 

 

 

 

 

 

Euploea midamus

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2(T1)

Eurema hecabe

2(T1)

2(T3)

1(T1)

2(T4)

1(T3)

1(T1)

1(T4)

2(T1)

3(T3)

1(T4)

2(T1)

1(T4)

2(T4)

 

1(T3)

 

2(T1)

1(T2)

1(T2)

1(T4

 

1(T1)

1(T2)

2(T4)

1(T1)

2(T2)

1(T1)

3(T2)

1(T4)

Hypolimnas bolina

 

 

 

 

1(T2)

1(T1)

 

 

 

 

 

 

 

 

 

 

Hypolimnas misippus

 

 

 

 

 

1(T1)

 

 

 

 

 

 

 

 

 

 

Junonia orithya

 

 

 

 

 

1(T5)

 

 

 

 

 

 

 

 

 

 

Lampides boeticus

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2(T3)

1(T3)

Mycalesis mineus

 

1(T5)

1(T2)

1(T2)

 

1(T2)

 

 

 

 

 

 

 

 

 

 

Papilio polytes

 

 

 

 

1(T1)

 

 

 

1(T5)

 

1(T2)

 

 

1(T1)

1(T5)

2(T2)

 

Papilio helenus

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1(T5)

Pieris canidia

 

 

 

 

 

 

2(T2)

 

 

 

 

 

 

 

 

 

Zizeeria maha

 

3(T2)

2(T5)

 

6(T2)

 

 

 

 

 

 

 

 

2(T2)

1(T2

3(T1)

2(T2)

1(T4)

4(T1)

2(T2)

2(T4)

 

2.3.6        Notable butterfly sightings made outside of the transects (i.e. of species not otherwise recorded) included the following:

 

Acytolepis puspa - 1 individual on road beside pond 53, 23 June; 1 individual ditto, 30 July; 2 individuals on road beside pond 51, 12 August.

 

Elymnias hypermnestra - 1 individual on road beside pond 53, 24 August.

 

Eurema laeta - 1 individual on road beside pond 51, 23 June. Rated uncommon locally by Walthew, 1997.

 

Papilio demoleus - 1 individual at ponds 3 and 7, 24 August.

 

 

Discussion

 

2.3.7        A total of 17 butterfly species were recorded along the transects at Lok Ma Chau. This fish pond area has very low floral diversity and is consequently of limited value for butterflies. The most notable record was Hypolimnas misippus, a normally rare species in Hong Kong, irruptive in occasional years (Bascombe et al., 1999), of which 2000 appears to have been an example (pers. obs.). The only other record of note was a single sighting of the Spotless Grass Yellow Eurema laeta on the wooded road running beneath the border crossing road, on 23 June.

 

Amphibians

 

2.3.8        The following tables provide a semi-quantitative assessment of individuals present, detected by vocalisations and/or spotlighting. I = 1 individual; II = 2-5 individuals; III = 6-10 individuals; IV = 11-20 individuals; V = >20 individuals.

 

Table 2.8 Amphibian Species Recorded at Transect 1

 

Species/date

22.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

26.4

27.4

5.5

22.5

31.5

Bufo melanosticta

II

II

I

 

 

I

 

 

III

II

 

 

I

 

Rana guentheri

II

III

II

II

II

II

 

 

II

I

 

III

 

II

Rana limnocharis

II

 

II

II

 

 

 

 

 

I

I

 

 

II

 

 

Table 2.9 Amphibian Species Recorded at Transect 2

 

Species/date

22.6

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

26.4

27.4

5.5

22.5

31.5

Bufo melanosticta

 

II

 

I

 

 

 

 

I

 

 

II

 

 

Polypedates megacephalus

I

 

I

 

 

 

 

 

 

 

 

 

 

 

Rana guentheri

II

I

 

II

I

 

 

 

 

 

 

 

 

II

Rana limnocharis

 

 

 

 

 

 

 

 

 

II

 

 

 

 

 

 

Table 2.10 Amphibian Species Recorded at Transect 3

 

Species/date

22.6

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

26.4

27.4

5.5

22.5

31.5

Bufo melanosticta

II

III

II

II

 

I

 

 

II

II

 

II

 

II

Polypedates megacephalus

I

I

 

I

 

 

 

 

I

I

 

II

 

I

Rana guentheri

III

III

II

II

 

II

I

 

III

II

 

III

 

 

Rana limnocharis

III

III

III

II

II

 

 

 

II

 

 

 

 

 

Rana rugulosa

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

Table 2.11 Amphibian Species Recorded at Transect 4

 

Species/date

22.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

26.4

27.4

5.5

22.5

31.5

Bufo melanosticta

I

 

I

 

 

 

 

 

 

 

 

 

 

 

Microhyla ornata

 

 

 

 

 

 

 

 

 

III

 

II

 

II

Microhyla pulchra

 

 

 

 

 

 

 

 

 

 

 

III

 

III

Polypedates megacephalus

 

 

 

 

 

 

 

 

 

 

 

 

 

I

Rana guentheri

I

 

II

I

 

 

 

 

II

 

 

III

 

 

Rana limnocharis

II

II

II

II

 

 

 

 

I

 

 

II

 

 

 

 

Table 2.12 Amphibian Species Recorded at Transect 5

 

Species/date

22.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

26.4

27.4

5.5

22.5

31.5

Bufo melanosticta

 

II

I

 

 

 

 

 

 

 

 

 

 

I

Rana guentheri

II

III

II

II

 

 

 

 

 

 

 

 

 

 

 

 

2.3.9        No notable amphibian records were made outside of the transects.

 

Discussion

 

2.3.10    Only common lowland amphibians were recorded (see Lau & Dudgeon, 1999). Ponds along the border road tended to have more bankside vegetation, less steep banks and, as a consequence, more amphibians congregating in them. Diversity was low, with generally only 3 or 4 species present (only 2 at transect 5). Semi-quantitative assessments of amphibian numbers should be regarded as conservative due to heavy bias towards males and consequent under-recording of females.

 

Reptiles

 

2.3.11    Results for all five transects are summarised in one table below (Table 2.13).

 

Table 2.13 Reptile species recorded along transects

 

Species/date

21.6.00

23.6

25.7

30.7

12.8

24.8

1.9

11.9

2.4.01

27.4

8.5

22.5

31.5

Calotes versicolor

1(T2)

 

 

 

1(T2)

 

 

 

 

 

 

1(T1)

1(T2)

 

Eumeces chinensis

1(T1)

1(T5)

2(T5)

 

1(T3)

1(T4)

1(T5)

1(T3)

1(T4)

2(T3)

2(T1)

2(T3)

2(T5)

1(T5)

1(T5)

 

2(T4)

1(T5)

 

 

Hemidactylus bowringii

 

 

1(T2)

 

 

 

 

 

 

1(T2)

1(T4)

2(T2)

 

 

Ptyas mucosus

 

 

 

1(T3)

 

 

 

 

 

 

1(T2)

 

 

Ramphotyphlops braminus

1(T2)

1(T2)

 

 

 

 

 

 

1(T2)

 

 

 

 

Xenochrophis piscator

 

 

 

 

1(T2)

 

 

 

 

 

 

 

1(T4) night

 

 

2.3.12    Notable reptile sightings made outside of the transects (i.e. of species not otherwise recorded) included the following:

 

Chinemys reevesii - 1 individual seen in pond 3 on 21 June.

 

Discussion

 

2.3.13    A total of 7 reptile species were recorded, none of which is of particular conservation concern, although Checkered Keelback Xenochrophis piscator, while still quite common, is regarded as having declined somewhat since the early 1980s as a direct consequence of wetland habitat loss (Karsen et al., 1998). Reeve's Terrapin Chinemys reevesii is thought to be in decline in Hong Kong due to competition from the introduced Red-eared Slider Trachemys scripta (Karsen et al., 1998).

 

Mammals

 

2.3.14    No evidence of mammals was encountered during the course of the transect surveys. However, a sighting of Small Asian Mongoose Herpestes javanicus was made at pond 61 on 14 June 2000. This species appears to be spreading and becoming quite common in the lowlands of the northwest New Territories. Much more notable is a recent (December) sighting of Eurasian Otter (Lutra lutra). This is a rare species in Hong Kong, restricted to wetlands in the northwest New Territories (see Reels, 1996). The otter was seen swimming in pond 40 on the morning of 6 December 2000. This species’ conservation status has been rated as “vulnerable” and of regional concern by Fellowes et al. (in prep.). However, there have been recent sightings at Mai Po (L. Young, pers. comm.) and at San Tin (P.J. Leader, pers. comm.), as well as at the Lok Ma Chau site. The animals are elusive and mainly active at night, and the possibility that they are under-recorded in Hong Kong cannot be ruled out.

 

2.4              Conclusion

 

2.4.1        Survey findings to date have indicated that the Lok Ma Chau site supports mainly common and widespread species of dragonfly, butterfly, amphibian, reptile and mammal, typical of disturbed lowland habitats in Hong Kong.

 

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