One of the main challenges in the conservation of biodiversity is to overcome inadequate knowledge about species and their intra-specific diversity. In the present study, we attempted to assess morphological distinction of the two previously identified genetic clades within the Luristan newt (Neurergus kaiseri, Schmidt 1952) endemic to Iran, which is essential for its conservation planning. Signals of the morphological variation in N. kaiseri were evaluated using landmark-based geometric morphometrics of body shape and characters of osteological structures. Morphological approaches revealed consistent groupings within the species, confirming the presence of two distinct lineages (previously named as the northern and southern clades). The morphological and genetic data provide evidence for the possible co-existence of two species in N. kaiseri and we recommend assigning the newly recognised forms to the species level.
{"title":"Morphological assessment raises the possibility of cryptic species within the Luristan newt, Neurergus kaiseri (Amphibia: Salamandridae)","authors":"M. Malekian","doi":"10.33256/29.4.237244","DOIUrl":"https://doi.org/10.33256/29.4.237244","url":null,"abstract":"One of the main challenges in the conservation of biodiversity is to overcome inadequate knowledge about species and their intra-specific diversity. In the present study, we attempted to assess morphological distinction of the two previously identified genetic clades within the Luristan newt (Neurergus kaiseri, Schmidt 1952) endemic to Iran, which is essential for its conservation planning. Signals of the morphological variation in N. kaiseri were evaluated using landmark-based geometric morphometrics of body shape and characters of osteological structures. Morphological approaches revealed consistent groupings within the species, confirming the presence of two distinct lineages (previously named as the northern and southern clades). The morphological and genetic data provide evidence for the possible co-existence of two species in N. kaiseri and we recommend assigning the newly recognised forms to the species level.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44908004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Here we report the local extinction of Scinax caldarum, an endemic tree frog species of the Brazilian Atlantic Forest. We also report a reduction of the geographic range of this species to less than 15 % of the area in which it occurred 27 years earlier. We consider the excessive use of agrochemicals to be the main factor explaining the decline, including in farms with environmental certification. The local extinction of S. caldarum is a bioindicator of the severe impact of crops such as coffee and sugar cane, which heavily rely on agrochemicals. Stricter regulation of pesticides is needed to avoid damage to ecosystems and loss of biodiversity.
{"title":"Local extinction of Scinax caldarum, a treefrog in Brazil’s Atlantic forest","authors":"L. Ferrante","doi":"10.33256/29.4.295298","DOIUrl":"https://doi.org/10.33256/29.4.295298","url":null,"abstract":"Here we report the local extinction of Scinax caldarum, an endemic tree frog species of the Brazilian Atlantic Forest. We also report a reduction of the geographic range of this species to less than 15 % of the area in which it occurred 27 years earlier. We consider the excessive use of agrochemicals to be the main factor explaining the decline, including in farms with environmental certification. The local extinction of S. caldarum is a bioindicator of the severe impact of crops such as coffee and sugar cane, which heavily rely on agrochemicals. Stricter regulation of pesticides is needed to avoid damage to ecosystems and loss of biodiversity.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49068988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Currently, herpetofauna worldwide is facing enormous threats; the number of threatened species is increasing at an alarming rate and many species have gone extinct. Despite efforts of institutions and researchers to understand and address the causes of declines and raise awareness of herpetofauna conservation, there has been no systematic study to evaluate the allocation of funding for basic and applied research relevant to conservation, relative publication rates, and the relationship of these measures to a degree of threat among herpetological groups. This study addresses this gap and identifies strengths and weaknesses of herpetological research and conservation over the last 10 years (2008-2018). Frogs had the highest grant-publication index (1384), followed by lizards (695), turtles (678), snakes (461.5), salamanders (366.5), crocodiles (164), caecilians (25.5), worm lizards (23) and tuatara (10). Nonetheless, when the grant-publication index is divided by the number of threatened and data-deficient species within each group, it demonstrates that, proportionally and in ascending order, salamanders, snakes, lizards, worm lizards, frogs and caecilians are in most need of knowledge and on-going funding for their conservation and survival. I was able to document a continued shift in attention in herpetological research owing to the emergence of chytridiomycosis and the global decline of amphibians. Despite some caveats, these findings should represent a proxy for the allocation of research and conservation effort on herpetofauna worldwide. I suggest priorities for research and how to better direct efforts to herpetofauna conservation.
{"title":"An assessment of funding and publication rates in Herpetology","authors":"Bruno O. Ferronato","doi":"10.33256/29.4.262273","DOIUrl":"https://doi.org/10.33256/29.4.262273","url":null,"abstract":"Currently, herpetofauna worldwide is facing enormous threats; the number of threatened species is increasing at an alarming rate and many species have gone extinct. Despite efforts of institutions and researchers to understand and address the causes of declines and raise awareness of herpetofauna conservation, there has been no systematic study to evaluate the allocation of funding for basic and applied research relevant to conservation, relative publication rates, and the relationship of these measures to a degree of threat among herpetological groups. This study addresses this gap and identifies strengths and weaknesses of herpetological research and conservation over the last 10 years (2008-2018). Frogs had the highest grant-publication index (1384), followed by lizards (695), turtles (678), snakes (461.5), salamanders (366.5), crocodiles (164), caecilians (25.5), worm lizards (23) and tuatara (10). Nonetheless, when the grant-publication index is divided by the number of threatened and data-deficient species within each group, it demonstrates that, proportionally and in ascending order, salamanders, snakes, lizards, worm lizards, frogs and caecilians are in most need of knowledge and on-going funding for their conservation and survival. I was able to document a continued shift in attention in herpetological research owing to the emergence of chytridiomycosis and the global decline of amphibians. Despite some caveats, these findings should represent a proxy for the allocation of research and conservation effort on herpetofauna worldwide. I suggest priorities for research and how to better direct efforts to herpetofauna conservation.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42051803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Jameson, Jayson D. Blankenship, T. Christensen, J. A. López, G. Garcia
In this study, we provide the most complete review to date of the diet of the critically endangered mountain chicken Leptodactylus fallax in the wild, describing for the first time the composition of the diet from Montserrat. To do this we report the results of two studies carried out on Montserrat that investigated L. fallax diet based on the content of frog gastrointestinal tracts. We found diets on Montserrat to be similar to that recorded for Dominica, typified by opportunism and catholicity, including a wide range of invertebrate prey (dominated by orthopterans) with some small vertebrates eaten too.
{"title":"Wild diet of the critically endangered mountain chicken (Leptodactylus fallax)","authors":"T. Jameson, Jayson D. Blankenship, T. Christensen, J. A. López, G. Garcia","doi":"10.33256/29.4.299303","DOIUrl":"https://doi.org/10.33256/29.4.299303","url":null,"abstract":"In this study, we provide the most complete review to date of the diet of the critically endangered mountain chicken Leptodactylus fallax in the wild, describing for the first time the composition of the diet from Montserrat. To do this we report the results of two studies carried out on Montserrat that investigated L. fallax diet based on the content of frog gastrointestinal tracts. We found diets on Montserrat to be similar to that recorded for Dominica, typified by opportunism and catholicity, including a wide range of invertebrate prey (dominated by orthopterans) with some small vertebrates eaten too.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49607208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The distribution of animal populations within an assemblage includes a wide variety of patterns, which are fundamental to understanding population dynamics and aid in conservation actions. We examined a snake assemblage in an urban area to describe species distribution patterns and to identify which places are more likely to contain snakes, both venomous and non-venomous. The study was conducted in the urban area of the municipality of Rio Tinto in north-east Brazil. We used a geostatistical modelling technique called ordinary kriging to identify which places were more likely to contain snakes, and a statistical spatial method (average nearest neighbour distance) to detect distribution patterns of snake species within the study area. A total of 291 individuals distributed among 28 species were recorded. The snakes were found in streets, homes, churches, university campus, streams, and even in local supermarkets. Ordinary kriging showed that the area of distribution of individuals was concentrated at three distinct points located in the centre of the urban area. The significant results of the average nearest neighbour distance analysis showed a clustered distribution for two species and dispersed distributions for eight species. Information on urban sites where snakes are more likely to be found is important not only for conservation, but also to help local citizens better understand and live amongst snakes
{"title":"Spatial patterns of snake diversity in an urban area of north-east Brazil","authors":"R. França","doi":"10.33256/29.4.274281","DOIUrl":"https://doi.org/10.33256/29.4.274281","url":null,"abstract":"The distribution of animal populations within an assemblage includes a wide variety of patterns, which are fundamental to understanding population dynamics and aid in conservation actions. We examined a snake assemblage in an urban area to describe species distribution patterns and to identify which places are more likely to contain snakes, both venomous and non-venomous. The study was conducted in the urban area of the municipality of Rio Tinto in north-east Brazil. We used a geostatistical modelling technique called ordinary kriging to identify which places were more likely to contain snakes, and a statistical spatial method (average nearest neighbour distance) to detect distribution patterns of snake species within the study area. A total of 291 individuals distributed among 28 species were recorded. The snakes were found in streets, homes, churches, university campus, streams, and even in local supermarkets. Ordinary kriging showed that the area of distribution of individuals was concentrated at three distinct points located in the centre of the urban area. The significant results of the average nearest neighbour distance analysis showed a clustered distribution for two species and dispersed distributions for eight species. Information on urban sites where snakes are more likely to be found is important not only for conservation, but also to help local citizens better understand and live amongst snakes","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43753590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In reintroduction programmes for amphibians, data on age structure in hosting populations and choices of life stage or age groups in releasing captive bred individuals are often missing. Similarly, employing site selection procedures for selecting appropriate reintroduction locations are often neglected. Here, we obtained data on longevity, age at maturation, and age structure from skeletochronological data in a free living population of the yellow spotted mountain newt, Neurergus derjugini. A maximum longevity of 13 years for males and 12 years for females showed that N. derjugini is a long living newt with a stable age structure. We also employed maximum entropy modelling, geographic information system, and multicriteria decision analysis to obtain ranked suitability scores for reintroduction sites. Finally, we determined post-release survival rates for different life stage and age groups of N. derjugini including 30 eggs and 60 individuals of six-months old larvae, one and three-year old juveniles, and six-year old adults (15 each) born and raised in a captive-breeding facility and released into mesh enclosures in a selected stream. Over 10 visits to the site before and after overwintering, the survival rates for eggs, larvae, one and three-year juveniles and six-year old adults were 25, 80, 86.66, 93.33 and 53.33 % respectively. Applying survival rates obtained from current experimental reintroductions through a static life table suggest that an optimal release strategy to arrive at a numerical target of 100 adults aged three can be achieved by reintroduction of 650 fertilised eggs and fostering them in meshed enclosures in the selected stream.
{"title":"Incorporating habitat suitability and demographic data for developing a reintroduction plan for the critically endangered yellow spotted mountain newt, Neurergus derjugini","authors":"S. Vaissi","doi":"10.33256/29.4.282294","DOIUrl":"https://doi.org/10.33256/29.4.282294","url":null,"abstract":"In reintroduction programmes for amphibians, data on age structure in hosting populations and choices of life stage or age groups in releasing captive bred individuals are often missing. Similarly, employing site selection procedures for selecting appropriate reintroduction locations are often neglected. Here, we obtained data on longevity, age at maturation, and age structure from skeletochronological data in a free living population of the yellow spotted mountain newt, Neurergus derjugini. A maximum longevity of 13 years for males and 12 years for females showed that N. derjugini is a long living newt with a stable age structure. We also employed maximum entropy modelling, geographic information system, and multicriteria decision analysis to obtain ranked suitability scores for reintroduction sites. Finally, we determined post-release survival rates for different life stage and age groups of N. derjugini including 30 eggs and 60 individuals of six-months old larvae, one and three-year old juveniles, and six-year old adults (15 each) born and raised in a captive-breeding facility and released into mesh enclosures in a selected stream. Over 10 visits to the site before and after overwintering, the survival rates for eggs, larvae, one and three-year juveniles and six-year old adults were 25, 80, 86.66, 93.33 and 53.33 % respectively. Applying survival rates obtained from current experimental reintroductions through a static life table suggest that an optimal release strategy to arrive at a numerical target of 100 adults aged three can be achieved by reintroduction of 650 fertilised eggs and fostering them in meshed enclosures in the selected stream.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49390500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"10. Spatial patterns of snake diversity in an urban area of north-east Brazil","authors":"Rafaela C França, F. França","doi":"10.33256/HJ29.4.274281","DOIUrl":"https://doi.org/10.33256/HJ29.4.274281","url":null,"abstract":"","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42719800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Sánchez, M. Semeñiuk, M. Cassano, Leandro Alcalde, G. Leynaud, L. Moreno
There are many cases of animals reported in localities away from natural areas of distribution for the species. With respect to native freshwater turtles of Argentina and bordering countries, several populations (and single specimens) were reported for areas that cast doubts about their origin, due to not only the long distance from other known localities but also the geographical barriers that are in between. The present work provides a review of localities of the native turtle species Hydromedusa tectifera, Phrynops hilarii, Acanthochelys pallidipectoris, A. spixii and Trachemys dorbigni in Argentina, Bolivia, Brasil, Paraguay and Uruguay, and adds new records for some of these species for Argentina. We also employ an analysis to recognise core and extralimital populations, and a methodology based on five criteria that must be taken into account to elucidate if one extralimital turtle record is the result of anthropogenic action or a case of natural occurrence. Finally, we discuss about the origin of extralimital reports of turtles of the mentioned species.
{"title":"Review of chelid and emydid turtle distributions in southern South America with emphasis on extralimital populations and new records for Argentina","authors":"R. Sánchez, M. Semeñiuk, M. Cassano, Leandro Alcalde, G. Leynaud, L. Moreno","doi":"10.33256/29.4.219229","DOIUrl":"https://doi.org/10.33256/29.4.219229","url":null,"abstract":"There are many cases of animals reported in localities away from natural areas of distribution for the species. With respect to native freshwater turtles of Argentina and bordering countries, several populations (and single specimens) were reported for areas that cast doubts about their origin, due to not only the long distance from other known localities but also the geographical barriers that are in between. The present work provides a review of localities of the native turtle species Hydromedusa tectifera, Phrynops hilarii, Acanthochelys pallidipectoris, A. spixii and Trachemys dorbigni in Argentina, Bolivia, Brasil, Paraguay and Uruguay, and adds new records for some of these species for Argentina. We also employ an analysis to recognise core and extralimital populations, and a methodology based on five criteria that must be taken into account to elucidate if one extralimital turtle record is the result of anthropogenic action or a case of natural occurrence. Finally, we discuss about the origin of extralimital reports of turtles of the mentioned species.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47354862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Maldives are coral reef islands of Holocene origin with no endemic terrestrial herpetofauna. The few species that have been reported from the region have affinities with Sri Lanka, south and south-east Asia, and are considered relatively recent introductions by humans. Recent collections of Hemidactylus geckos from the Maldives allowed us to identify and reconstruct the probable origin of this genus on the islands. We combine mitochondrial DNA (ND2) sequence data for the new collections with published sequences to reconstruct evolutionary relationships. The two species of Hemidactylus in the Maldives are H. frenatus and H. parvimaculatus, with affinities to south-east Asia and Sri Lanka, respectively. Suggestive of multiple introductions, each species included multiple haplotypes, only one of which was previously recorded (in Sri Lanka); other haplotypes showed similarities to records from south-east Asia. Unravelling the colonisation patterns of house geckos in the Maldives requires a more complete knowledge of the natural variation across the range of the widely distributed source species.
{"title":"The identity and probable origin of the Hemidactylus geckos of the Maldives","authors":"Ishan Agarwal","doi":"10.33256/29.4.230236","DOIUrl":"https://doi.org/10.33256/29.4.230236","url":null,"abstract":"The Maldives are coral reef islands of Holocene origin with no endemic terrestrial herpetofauna. The few species that have been reported from the region have affinities with Sri Lanka, south and south-east Asia, and are considered relatively recent introductions by humans. Recent collections of Hemidactylus geckos from the Maldives allowed us to identify and reconstruct the probable origin of this genus on the islands. We combine mitochondrial DNA (ND2) sequence data for the new collections with published sequences to reconstruct evolutionary relationships. The two species of Hemidactylus in the Maldives are H. frenatus and H. parvimaculatus, with affinities to south-east Asia and Sri Lanka, respectively. Suggestive of multiple introductions, each species included multiple haplotypes, only one of which was previously recorded (in Sri Lanka); other haplotypes showed similarities to records from south-east Asia. Unravelling the colonisation patterns of house geckos in the Maldives requires a more complete knowledge of the natural variation across the range of the widely distributed source species.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49278382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 31-year study monitored Britain’s largest natterjack toad population on the Sefton Coast sand-dune system in north-west England. Key objectives were to describe changes in numbers and breeding success, relate these to environmental variables and explore whether conservation efforts have been well targeted. Considerable variation was found in the number of water bodies used for spawning, the number of spawn strings laid and breeding success based on estimated toadlet production. There was a declining trend in annual totals of spawn strings and toadlets. Positive correlations were established between spring and April rainfall and both spawn count and toadlet production. April rainfall for the study area declined between 2000 and 2017. Premature desiccation of water bodies and associated poor breeding success were frequently observed, there being a positive relationship between water-table height and toadlet numbers. A long-term declining trend in the height of the water-table was established. The mean adult population of Sefton natterjacks was estimated at about 1200 individuals, with a peak around 3150. Successful breeding is increasingly reliant on management to excavate appropriately designed and managed “scrapes” that hold water long enough for metamorphosis to occur. Overgrowth of vegetation and loss of dynamism in the dune system threaten both the natural production of new breeding slacks and the natterjack’s open terrestrial habitat. Encouragement of dune dynamics by removing trees and scrub, increasing areas subject to livestock grazing and mechanical rejuvenation may offer the best hope of conserving this species in the future.
{"title":"Effects of environmental factors and conservation measures on a sand-dune population of the natterjack toad (Epidalea calamita) in north-west England: a 31-year study","authors":"P. Smith, G. Skelcher","doi":"10.33256/HJ29.3.146154","DOIUrl":"https://doi.org/10.33256/HJ29.3.146154","url":null,"abstract":"A 31-year study monitored Britain’s largest natterjack toad population on the Sefton Coast sand-dune system in north-west England. Key objectives were to describe changes in numbers and breeding success, relate these to environmental variables and explore whether conservation efforts have been well targeted. Considerable variation was found in the number of water bodies used for spawning, the number of spawn strings laid and breeding success based on estimated toadlet production. There was a declining trend in annual totals of spawn strings and toadlets. Positive correlations were established between spring and April rainfall and both spawn count and toadlet production. April rainfall for the study area declined between 2000 and 2017. Premature desiccation of water bodies and associated poor breeding success were frequently observed, there being a positive relationship between water-table height and toadlet numbers. A long-term declining trend in the height of the water-table was established. The mean adult population of Sefton natterjacks was estimated at about 1200 individuals, with a peak around 3150. Successful breeding is increasingly reliant on management to excavate appropriately designed and managed “scrapes” that hold water long enough for metamorphosis to occur. Overgrowth of vegetation and loss of dynamism in the dune system threaten both the natural production of new breeding slacks and the natterjack’s open terrestrial habitat. Encouragement of dune dynamics by removing trees and scrub, increasing areas subject to livestock grazing and mechanical rejuvenation may offer the best hope of conserving this species in the future.","PeriodicalId":56131,"journal":{"name":"Herpetological Journal","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47575448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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