scholarly journals A re-evaluation of the occurrence of freshwater molluscs in the Kruger National Park

Koedoe ◽  
1998 ◽  
Vol 41 (1) ◽  
Author(s):  
K.N. De Kock ◽  
C.T. Wolmarans
Keyword(s):  
Species Diversity ◽  
National Park ◽  
Kruger National Park ◽  
Intermediate Hosts ◽  
Freshwater Molluscs ◽  
Freshwater Mollusc ◽  
Mollusc Species ◽  
Trematode Parasites

Most of the previous records of the freshwater molluscs from the Kruger National Park date back prior to and up to 1966. On account of several droughts between 1966 and 1995 it was decided to do a survey of the freshwater mollusc population in 1995 to evaluate the effect of these droughts. The traditional mollusc intermediate hosts were also screened for trematode parasites to establish whether or not they were infected. No infected molluscs were found. Eight of the 19 species reported up to 1966 were not found during the 1995 survey. Three new mollusc species were collected in 1995. The consequences of the drought are clearly visible when the species diversity found in the dams in the 1995 survey, is compared to what was previously recorded.

scholarly journals The current status of freshwater molluscs in the Kruger National Park

Koedoe ◽  
2006 ◽  
Vol 49 (2) ◽  
Author(s):  
C.T. Wolmarans ◽  
K.N. De Kock
Keyword(s):  
Species Diversity ◽  
National Park ◽  
Kruger National Park ◽  
Current Status ◽  
Freshwater Molluscs ◽  
Freshwater Mollusc ◽  
Current Survey ◽  
Mollusc Species ◽  
Flow Through ◽  
Alien Invader

Surveys regarding the freshwater mollusc population of the Kruger National Park commenced before 1966 and was repeated in 1995, 2001 and recently in 2006. During this period the park was exposed to several droughts as well as floods, all of which could have had some influence on the various habitats in the park. Industrial developments and urbanisation near some of the major rivers outside the park, but which flow through the park, could also have a detrimental effect on the species diversity of the freshwater molluscs. The recent survey in 45 habitats included several dams and rivers. The survey was done to determine the current status of the mollusc species diversity. By comparing it with previous surveys, an attempt was made to establish the overall health of freshwater mollusc habitats. From the results it is clear that there was a drastic decrease in the mollusc species diversity in five of the habitats. Although there was a slight change in the species composition in some of the major rivers there was no difference in the number of species collected in these habitats. Tarebia granifera, an alien invader mollusc, was found in several rivers and dams. Gyraulus costulatus, Melanoides victoriae and Eupera ferruginea, which could not be found during the survey of 2001, were collected during the current survey.

scholarly journals Freshwater mollusc diversity in the Kruger National Park: a comparison between a period of prolonged drought and a period of exceptionally high rainfall

Koedoe ◽  
2002 ◽  
Vol 45 (2) ◽  
Author(s):  
K.N. De Kock ◽  
C.T. Wolmarans ◽  
L.H. Du Preez
Keyword(s):  
Species Diversity ◽  
National Park ◽  
Freshwater Snail ◽  
Kruger National Park ◽  
Snail Species ◽  
High Rainfall ◽  
Freshwater Molluscs ◽  
Freshwater Mollusc ◽  
Prolonged Drought ◽  
Positive Effect

Most of the previous records of the freshwater molluscs from the Kruger National Park date back to 1966 and earlier. On account of several droughts between 1966 and 1995, a survey was done in 1995 to evaluate the effect of these droughts on the mollusc population. As a result of extensive rainfall between 1995 and 2000 another survey was conducted to establish the effect of a period of exceptionally high rainfall on the species’ diversity of the mollusc population. With the exception of three habitats, an increase in mollusc diversity was recorded for all the other habitats previously surveyed. One of the invader freshwater snail species, Aplexa marmorata, collected in only one habitat in 1995, was found in seven habitats located mainly in the south during the 2001 survey. Another interesting finding was that juvenile specimens of Lanistes ovum, of which large specimens were present prior to 1966 but none found in 1995, were present in the Sirheni Dam in 2001. From this study the positive effect of the high rainfall on the species’ diversity is highly evident.

The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status

Zootaxa ◽  
2021 ◽  
Vol 5003 (1) ◽  
pp. 1-64
Author(s):  
VANJA MARKOVIĆ ◽  
VUKAŠIN GOJŠINA ◽  
BORIS NOVAKOVIĆ ◽  
MILENKA BOŽANIĆ ◽  
KATARINA STOJANOVIĆ ◽  
...  
Keyword(s):  
National Level ◽  
Danube River ◽  
Freshwater Molluscs ◽  
Melanoides Tuberculata ◽  
Invasive Biology ◽  
Regional Trends ◽  
Freshwater Mollusc ◽  
Mollusc Species ◽  
Local Endemic ◽  
Annotated Checklist

We present a checklist of 86 valid freshwater mollusc species of Serbia (65 gastropods and 21 bivalves) belonging to 19 families (15 gastropods and four bivalves). The list is based on our latest research and includes data from published sources and personal communications. The most diverse family among gastropods is Planorbidae (16 species), while Sphaeriidae are most diverse within the bivalves (10 species). Ten species are local endemics (all of them gastropods), while eight are introduced species (three gastropods and five bivalves). The Danube River and its smaller tributaries harbour the most diverse gastropod community, with a total of 61 species (41 gastropods and 20 bivalves). The snail Theodoxus transversalis (Pfeiffer, 1828) and the bivalve Unio crassus Philipson, 1788 are listed as EN (endangered) on the global (IUCN) level, while the snail Plagigeyeria gladilini Kuščer, 1937 and the bivalves Pseudanodonta complanata (Rossmässler, 1835) and Sphaerium rivicola (Lamarck, 1818) are considered as VU (vulnerable) species. Of those IUCN taxa, only U. crassus is listed as protected on the national level (along with 12 mostly local endemic gastropod species). In comparison with the previous checklist of gastropods by Karaman & Karaman (2007), a total of seven species are added here: Belgrandiella serbica Glöer 2008, Bythinella istoka Glöer & Pešić 2014, B. nonveilleri Glöer 2008, B. pesterica Glöer 2008, Acroloxus lacustris (Linnaeus, 1758), Melanoides tuberculata (O.F. Müller, 1774) and Armiger crista (Linnaeus, 1758). In view of global and regional trends in taxonomy, ecology and invasive biology, an even richer diversity of the Serbian freshwater malocofauna can be expected.  

scholarly journals Herbaceous species diversity patterns across various treatments of herbivory and fire along the sodic zone of the Nkuhlu exclosures, Kruger National Park

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Helga Van Coller ◽  
Frances Siebert ◽  
Stefan J. Siebert
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Significant Variation ◽  
National Park ◽  
Plant Species Richness ◽  
Kruger National Park ◽  
Riparian Zones ◽  
Herbaceous Plant ◽  
Herbaceous Species

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones is critical to biodiversity conservation. The Nkuhlu exclosures in the Kruger National Park (KNP) provided opportunity to investigate spatial heterogeneity patterns within riparian zones, as well as how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions about the dynamics of the herbaceous layer and was aimed at determining, (1) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments in the ecologically sensitive sodic zone and (2) whether an increase in herbaceous biomass, an artefact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of 81 fixed plots. The biomass of each plot was estimated with a disc pasture meter (DPM) diagonally with the plot. DPM-readings were converted to kg/ha, according to the latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass is significantly higher in fully fenced areas where herbivores are excluded, as opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. Therefore herbivores are essential in sustaining herbaceous plant species richness in the sodic zone, whilst no significant results were found with regard to their effect on species diversity. Although statistically non-significant, fire seems to suppress species richness.Conservation implications: This study could be used as framework to advance and develop science-based management strategies for, at least, the sodic zones of the KNP. Research in these exclosures will create better understanding of these landscapes, benefit ecosystem conservation planning of national parks and also provide valuable long-term information on key ecological processes.

scholarly journals Freshwater molluscs of the Zrmanja and Krupa Rivers (Croatia) – the role of these rivers as a refuge of threatened and endemic species

2021 ◽  
Vol 29 (2) ◽  
Author(s):  
Luboš Beran
Keyword(s):  
Endemic Species ◽  
Anthropogenic Factors ◽  
Widespread Species ◽  
Underground Waters ◽  
Freshwater Molluscs ◽  
Freshwater Mollusc ◽  
Distributional Information ◽  
Mollusc Species ◽  
Balkan Region ◽  
Mollusc Assemblages

The Balkan region is inhabited by hundreds of endemic species of freshwater molluscs but the information on their distribution, as well as that on the distribution of more common and widespread species, is still insufficient; most areas have no complete inventories of their mollusc faunas. The Zrmanja is one of the largest rivers in the Adriatic part of Croatia. Its freshwater molluscs were studied in the last decade, resulting in a substantial body of distributional data. The main objective of this study was to summarise and analyse the recent distributional information on its freshwater molluscs, with special reference to endemic or threatened species. In total 33 freshwater mollusc species were found in the Zrmanja River and its tributaries at 73 sites. The middle section of the Zrmanja River and its largest tributary, the Krupa River, were the richest studied parts. Dalmatinella fluviatilis Radoman, Tanousia zrmanjae (Brusina) and Islamia zermanica Radoman, endemic to the Zrmanja catchment area, were found in the middle and lower sections of the river. Their occurrence is scattered and limited in area; T. zrmanjae is probably on the verge of extinction. The occurrence of the endemic Belgrandiella kusceri (Wagner), Hadziella sketi Bole and Kerkia sp. in springs or underground waters and an abundant population of Unio elongatulus C. Pfeiffer in the Zrmanja and Krupa Rivers is also noteworthy. The area can be regarded as an important part of the Balkan region, one of world’s hotspots of global biodiversity. Although it is protected, there are still anthropogenic factors that are negatively affecting or may affect the mollusc assemblages.

scholarly journals Diversity of freshwater molluscs from the upper Brahmaputra Basin, Assam, India

2021 ◽  
Vol 13 (5) ◽  
pp. 18237-18246
Author(s):  
Jyotish Sonowal ◽  
Munmi Puzari ◽  
Devid Kardong
Keyword(s):  
Large Fraction ◽  
Geographical Area ◽  
Iucn Red List ◽  
Flood Plains ◽  
Freshwater Molluscs ◽  
Freshwater Mollusc ◽  
Total Geographical Area ◽  
Mollusc Species ◽  
Brahmaputra Basin ◽  
Data Deficient

A field survey was conducted for three consecutive years, 2015–17 to assess the diversity of freshwater molluscs (Gastropoda and Bivalvia) of the upper Brahmaputra Basin in Assam, India.  Altogether, 18 gastropods and 27 bivalve species representing nine families were recorded from 17 sampling stations comprising small to large tributaries and wetlands in the flood-plains covering a total geographical area of approximately 3,500km2.  A large fraction (15.55%) of the collected mollusc species are new records from the upper Brahmaputra Basin of Assam.  Rarity in the occurrence of freshwater mollusc was confirmed with singleton and doubleton species accounting for 6.66% and unique species accounting for 35.55% of the total species recorded.  It was observed that most of the mollusc species of the upper Brahmaputra Basin are either in the ‘Least Concern’ or ‘Data Deficient’ category of the IUCN Red List; except for Lymnaea ovalior (Annandale & Prashad, 1921) and Sphaerium austeni Prashad, 1921 assessed as ‘Vulnerable’ and ‘Near Threatened’, respectively.  A significant trend in the diversity in terms of species richness and composition was observed across the sampling stations of the northern basin and southern basin of the river Brahmaputra. 

scholarly journals Responses of freshwater molluscs to environmental factors in Southern Brazil wetlands

2010 ◽  
Vol 70 (3) ◽  
pp. 473-482 ◽  
Author(s):  
L. Maltchik ◽  
C. Stenert ◽  
CB. Kotzian ◽  
D. Pereira
Keyword(s):  
Aquatic Ecosystems ◽  
Aquatic Vegetation ◽  
Neotropical Region ◽  
Southern Brazil ◽  
Water Conductivity ◽  
Wetland Area ◽  
Freshwater Molluscs ◽  
Intermittent Wetlands ◽  
Freshwater Mollusc ◽  
Mollusc Species

Freshwater molluscs play an important role in aquatic ecosystems, providing food for many fish species and vertebrates. Investigations on factors that determine mollusc species richness and distribution in wetland systems are scarce in the Neotropical region. The main goal of this study was to determine how much variation in mollusc richness and composition is explained by area, hydroperiod, altitude, water conductivity, and dominant aquatic vegetation. This survey was performed in an extensive area of a Neotropical region (~280,000 km² in southern Brazil), with a large number of wetland systems (111) and covering a wide gradient of altitude and wetland surface area. The mollusc richness was positively associated with wetland area and negatively associated with altitude. The richness and composition of the freshwater molluscs were similar between permanent and intermittent wetlands and it did not differ significantly between aquatic bed and emergent wetlands. The first three axes of CCA explained 16.2% of the total variation in the composition of the freshwater mollusc observed. The variation in the composition had a correlation with wetland area, altitude and water conductivity. Our results showed that the wetlands are important habitats for molluscs in southern Brazil, and that the richness and the composition of molluscs were associated with area, altitude, water conductivity and dominant vegetation.

The freshwater molluscs of the Kruger National Park

Koedoe ◽  
1967 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Oberholzer ◽  
J. A. Van Eeden
Keyword(s):  
National Park ◽  
Kruger National Park ◽  
Freshwater Molluscs

The freshwater molluscs of the Kruger National Park

scholarly journals Invasive alien freshwater snail species in the Kruger National Park, South Africa

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Kenné N. De Kock ◽  
Cornelius T. Wolmarans
Keyword(s):  
South Africa ◽  
Species Diversity ◽  
National Park ◽  
Negative Impact ◽  
Freshwater Snail ◽  
Kruger National Park ◽  
Water Bodies ◽  
Snail Species ◽  
Physa Acuta ◽  
Tarebia Granifera

An account is given of all invasive alien freshwater snail species samples found in the Kruger National Park currently on record in the National Freshwater Snail Collection(NFSC) database. This report mainly focuses on samples collected during surveys of selected water bodies in the Kruger National Park (KNP) during 1964, 1995, 2001 and 2006. The progress made by four alien invasive freshwater snail species, Lymnaea columella, Physa acuta, Aplexa marmorata and Tarebia granifera, in colonising water bodies since first being recorded in the KNP is addressed. The results clearly show that all four species are in the process of becoming more widespread than they were when first recorded. However, T. granifera is the only one of these species of which exceptionally dense populations were encountered in several water bodies. All indications are that this species could already have had a negative impact on the species diversity of molluscs in these water bodies, and it is recommended that the situation be closely monitored.

scholarly journals The influence of fire on populations of small mammals of the Kruger National Park

Koedoe ◽  
1981 ◽  
Vol 24 (1) ◽  
Author(s):  
N. G Kern
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Small Mammals ◽  
Small Mammal ◽  
National Park ◽  
Kruger National Park ◽  
Control Treatment ◽  
Mammal Species ◽  
Low Diversity ◽  
Small Mammal Species

A total of 16 000 trap-nights was employed over eleven months to examine the influence of burning on small mammal populations in two major veld-types of the Kruger National Park. Four burning treatments (control, annual August burning, triennial August and April burning) were examined in detail and the following parameters determined: small mammal species composition, population density, biomass and species diversity. The control treatment had a high, stable small mammal density, biomass and diversity; the annual burning treatment had a low diversity and was dominated by Tatera leucogaster. The triennial burning treatments showed a cycle of species composition from domination by T. leucogaster following burning, through domination by other rodent species to domination by Crocidura hirta at the end of the cycle. The distributions and movements of the small mammals can be explained in terms of cover and litter preferences.

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