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Postgraduate Thesis: Impacts of illegal trapping and plantation forestry on herpetofaunal populations
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TitleImpacts of illegal trapping and plantation forestry on herpetofaunal populations
 
AuthorsSung, Yik-hei.
宋亦希.
 
Issue Date2012
 
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
 
AbstractGlobally, as many as 30% of amphibians and 23% of reptile species are threatened and require urgent conservation action. The major threats are primarily caused by anthropogenic activities. This research aimed to investigate the impacts of two anthropogenic threats, over-exploitation and habitat changes on herpetofaunal populations in Hong Kong. Platysternon megacephalum has been heavily depleted because of severe hunting pressure for the food and pet trades. Low densities of individuals and few remaining intact populations have limited our ability to study their ecology. I conducted mark-recapture and radio-telemetry studies on P.megacephalum populations in five streams in Hong Kong, one of which was free from trapping, over 34 months (2009–2011) to investigate the impacts of illegal trapping on populations of P.megacephalum and their spatial ecology and growth. Illegal trapping was associated with the absence of large adults, smaller body sizes of adults and skewed ratios of juveniles to adults. Home ranges were relatively small with a mean 100% minimum convex polygon 996m2. Males moved longer distances than females and both sexes moved longer distances in wet seasons. P.megacephalum was highly aquatic, preferring to stay in pools, and their microhabitat preferences were affected by stream width and depth, and substrate types. Juvenile P.megacephalum grew rapidly, with growth declining after attainment of sexual maturity. The average ages of sexual maturation were eight years for females. Illegal trapping remains the major threat to P.megacephalum populations and I recommend that regulatory personnel identify key streams and patrol regularly against illegal trapping to safeguard remaining populations. In Hong Kong, large areas of primary forest have been replaced by secondary forests and plantations, and changes in tree species composition have often led to alteration of associated plant and animal communities. I examined the herpetofaunal assemblages in secondary forests and exotic Lophostemon confertus plantations. Amphibian abundances were higher in secondary forests while reptile abundance, species richness of amphibian and reptiles were similar. Secondary forests provided better habitats for amphibians and I recommend the planting of a mixture of native tree species and the thinning of exotic trees in future plantation management efforts in South China. Our knowledge about the effectiveness of different herpetofaunal survey methods in Southeast Asia is limited. To fill the information gap, I examined the effectiveness of three survey methods, including transect surveys, pitfall traps and coverboards, for sampling terrestrial herpetofauna. Transect surveys were most effective at sampling species richness and pitfall traps were most efficient in capturing high numbers of reptiles. The results of this study will aid researchers in assessing the feasibility of and choosing herpetofaunal survey methods in Southeast Asia. Despite the severe threats that herpetofauna are facing, our understanding of their ecology and conservation needs remains limited. More research and the initiation of monitoring programs for herpetofauna, strengthened enforcement of existing regulations, and proper habitat management are crucial for the conservation of herpetofauna in South China.
 
AdvisorsHau, CH
Karraker, NE
 
DegreeDoctor of Philosophy
 
SubjectAmphibians - China - Hong Kong.
Reptiles - China - Hong Kong.
Amphibians - China, South.
Reptiles - China, South.
Forests and forestry - China - Hong Kong.
Forests and forestry - China, South.
Animal traps - China - Hong Kong.
Animal traps - China, South.
 
Dept/ProgramBiological Sciences
 
DC FieldValue
dc.contributor.advisorHau, CH
 
dc.contributor.advisorKarraker, NE
 
dc.contributor.authorSung, Yik-hei.
 
dc.contributor.author宋亦希.
 
dc.date.hkucongregation2012
 
dc.date.issued2012
 
dc.description.abstractGlobally, as many as 30% of amphibians and 23% of reptile species are threatened and require urgent conservation action. The major threats are primarily caused by anthropogenic activities. This research aimed to investigate the impacts of two anthropogenic threats, over-exploitation and habitat changes on herpetofaunal populations in Hong Kong. Platysternon megacephalum has been heavily depleted because of severe hunting pressure for the food and pet trades. Low densities of individuals and few remaining intact populations have limited our ability to study their ecology. I conducted mark-recapture and radio-telemetry studies on P.megacephalum populations in five streams in Hong Kong, one of which was free from trapping, over 34 months (2009–2011) to investigate the impacts of illegal trapping on populations of P.megacephalum and their spatial ecology and growth. Illegal trapping was associated with the absence of large adults, smaller body sizes of adults and skewed ratios of juveniles to adults. Home ranges were relatively small with a mean 100% minimum convex polygon 996m2. Males moved longer distances than females and both sexes moved longer distances in wet seasons. P.megacephalum was highly aquatic, preferring to stay in pools, and their microhabitat preferences were affected by stream width and depth, and substrate types. Juvenile P.megacephalum grew rapidly, with growth declining after attainment of sexual maturity. The average ages of sexual maturation were eight years for females. Illegal trapping remains the major threat to P.megacephalum populations and I recommend that regulatory personnel identify key streams and patrol regularly against illegal trapping to safeguard remaining populations. In Hong Kong, large areas of primary forest have been replaced by secondary forests and plantations, and changes in tree species composition have often led to alteration of associated plant and animal communities. I examined the herpetofaunal assemblages in secondary forests and exotic Lophostemon confertus plantations. Amphibian abundances were higher in secondary forests while reptile abundance, species richness of amphibian and reptiles were similar. Secondary forests provided better habitats for amphibians and I recommend the planting of a mixture of native tree species and the thinning of exotic trees in future plantation management efforts in South China. Our knowledge about the effectiveness of different herpetofaunal survey methods in Southeast Asia is limited. To fill the information gap, I examined the effectiveness of three survey methods, including transect surveys, pitfall traps and coverboards, for sampling terrestrial herpetofauna. Transect surveys were most effective at sampling species richness and pitfall traps were most efficient in capturing high numbers of reptiles. The results of this study will aid researchers in assessing the feasibility of and choosing herpetofaunal survey methods in Southeast Asia. Despite the severe threats that herpetofauna are facing, our understanding of their ecology and conservation needs remains limited. More research and the initiation of monitoring programs for herpetofauna, strengthened enforcement of existing regulations, and proper habitat management are crucial for the conservation of herpetofauna in South China.
 
dc.description.naturepublished_or_final_version
 
dc.description.thesisdisciplineBiological Sciences
 
dc.description.thesisleveldoctoral
 
dc.description.thesisnameDoctor of Philosophy
 
dc.identifier.hkulb4819930
 
dc.languageeng
 
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)
 
dc.relation.ispartofHKU Theses Online (HKUTO)
 
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.
 
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License
 
dc.source.urihttp://hub.hku.hk/bib/B48199308
 
dc.subject.lcshAmphibians - China - Hong Kong.
 
dc.subject.lcshReptiles - China - Hong Kong.
 
dc.subject.lcshAmphibians - China, South.
 
dc.subject.lcshReptiles - China, South.
 
dc.subject.lcshForests and forestry - China - Hong Kong.
 
dc.subject.lcshForests and forestry - China, South.
 
dc.subject.lcshAnimal traps - China - Hong Kong.
 
dc.subject.lcshAnimal traps - China, South.
 
dc.titleImpacts of illegal trapping and plantation forestry on herpetofaunal populations
 
dc.typePG_Thesis
 
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<contributor.advisor>Karraker, NE</contributor.advisor>
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<date.issued>2012</date.issued>
<description.abstract>&#65279;Globally, as many as 30% of amphibians and 23% of reptile species are threatened and require urgent conservation action.  The major threats are primarily caused by anthropogenic activities. This research aimed to investigate the impacts of two anthropogenic threats, over-exploitation and habitat changes on herpetofaunal populations in Hong Kong.



Platysternon megacephalum has been heavily depleted because of severe hunting pressure for the food and pet trades. Low densities of individuals and few remaining intact populations have limited our ability to study their ecology. I conducted mark-recapture and radio-telemetry studies on P.megacephalum populations in five streams in Hong Kong, one of which was free from trapping, over 34 months (2009&#8211;2011) to investigate the impacts of illegal trapping on populations of P.megacephalum and their spatial ecology and growth.  Illegal trapping was associated with the absence of large adults, smaller body sizes of adults and skewed ratios of juveniles to adults.  Home ranges were relatively small with a mean 100% minimum convex polygon 996m2.  Males moved longer distances than females and both sexes moved longer distances in wet seasons.  P.megacephalum was highly aquatic, preferring to stay in pools, and their microhabitat preferences were affected by stream width and depth, and substrate types.  Juvenile P.megacephalum grew rapidly, with growth declining after attainment of sexual maturity.  The average ages of sexual maturation were eight years for females.  Illegal trapping remains the major threat to P.megacephalum populations and I recommend that regulatory personnel identify key streams and patrol regularly against illegal trapping to safeguard remaining populations.

In Hong Kong, large areas of primary forest have been replaced by secondary forests and plantations, and changes in tree species composition have often led to alteration of associated plant and animal communities. I examined the herpetofaunal assemblages in secondary forests and exotic Lophostemon confertus plantations.  Amphibian abundances were higher in secondary forests while reptile abundance, species richness of amphibian and reptiles were similar. Secondary forests provided better habitats for amphibians and I recommend the planting of a mixture of native tree species and the thinning of exotic trees in future plantation management efforts in South China.

Our knowledge about the effectiveness of different herpetofaunal survey methods in Southeast Asia is limited.  To fill the information gap, I examined the effectiveness of three survey methods, including transect surveys, pitfall traps and coverboards, for sampling terrestrial herpetofauna.  Transect surveys were most effective at sampling species richness and pitfall traps were most efficient in capturing high numbers of reptiles. The results of this study will aid researchers in assessing the feasibility of and choosing herpetofaunal survey methods in Southeast Asia.

Despite the severe threats that herpetofauna are facing, our understanding of their ecology and conservation needs remains limited.  More research and the initiation of monitoring programs for herpetofauna, strengthened enforcement of existing regulations, and proper habitat management are crucial for the conservation of herpetofauna in South China.</description.abstract>
<language>eng</language>
<publisher>The University of Hong Kong (Pokfulam, Hong Kong)</publisher>
<relation.ispartof>HKU Theses Online (HKUTO)</relation.ispartof>
<rights>The author retains all proprietary rights, (such as patent rights) and the right to use in future works.</rights>
<rights>Creative Commons: Attribution 3.0 Hong Kong License</rights>
<source.uri>http://hub.hku.hk/bib/B48199308</source.uri>
<subject.lcsh>Amphibians - China - Hong Kong.</subject.lcsh>
<subject.lcsh>Reptiles - China - Hong Kong.</subject.lcsh>
<subject.lcsh>Amphibians - China, South.</subject.lcsh>
<subject.lcsh>Reptiles - China, South.</subject.lcsh>
<subject.lcsh>Forests and forestry - China - Hong Kong.</subject.lcsh>
<subject.lcsh>Forests and forestry - China, South.</subject.lcsh>
<subject.lcsh>Animal traps - China - Hong Kong.</subject.lcsh>
<subject.lcsh>Animal traps - China, South.</subject.lcsh>
<title>Impacts of illegal trapping and plantation forestry on herpetofaunal populations</title>
<type>PG_Thesis</type>
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<date.hkucongregation>2012</date.hkucongregation>
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