Michelle Hamer

Using commonality analysis in multiple regressions: a tool to decompose regression effects in the face of multicollinearity

tool to decompose regression effects in the face of multicollinearity Jayanti Ray-Mukherjee*, KimNimon, ShomenMukherjee, DouglasW.Morris, RobSlotow andMichelle Hamer TheSchool of Life Sciences, University of KwaZulu-Natal,Westville Campus, Private Bag: X54001, Durban 4000, South Africa; Learning Technologies andCollege of Information, University of North Texas, 3940N. Elm, RmG150Denton, TX, 76207, USA; Department of Biology, LakeheadUniversity, Thunder Bay, ON, P7B 5E1, Canada; and South AfricanNational Biodiversity Institute, Private BagX101, Pretoria 0001, South Africa

Sampling strategies for millipedes (Diplopoda), centipedes (Chilopoda) and scorpions (Scorpionida) in savanna habitats

At present considerable effort is being made to document and describe invertebrate diversity as part of numerous biodiversity conservation research projects. In order to determine diversity, rapid and effective sampling and estimation procedures are required and these need to be standardized for a particular group of organisms to allow for comparisons between studies and habitat types. The savanna biome is one of the largest and most important in Africa; however, it is also one of the most poorly studied, especially in terms of invertebrates. This study was undertaken in the Greater Makalali Conservancy, Limpopo Province, South Africa. The effectiveness of six sampling methods (pitfall traps, active searching one 25 m2 nested quadrat, active searching ten 2.25 m2 random quadrats, cryptozoan traps, wet cloths and drive transects) was tested to determine which method, or combination of methods, was the best for sampling millipedes, centipedes and scorpions in the savanna environment. Active searching in a 9 m 2 area was the most effective way to sample millipede species, while the drive transect method was important for sampling larger millipede species. Both the active searching of the nested quadrats and the random quadrats proved to be the most effective methods to sample centipedes. Scorpions were most effectively sampled using pitfall traps. Efficiency for all methods was calculated as the number of species collected per hour. The most effective method was not always the most efficient one, and this needs to be considered when designing a sampling strategy. Sampling more than one period in the summer is important for determining species richness. The number of random quadrats required to sample the fauna is likely to vary in different habitats, and there is a large amount of variation in the number of species collected between samples, which is probably related to high levels of habitat heterogeneity on a small scale. These points, as well as the size, mobility and other biological features of taxa need to be considered in designing a sampling strategy for invertebrates.

Development and Future of Insect Conservation in South Africa

When considering the history of insect conservation activities in South Africa, it is important to consider its biodiversity value in a global context. The country has been rated as the third most biologically diverse in the world after Indonesia and Brazil. It also has within its borders three or the world’s 34 biodiversity hotspots (Mittermeier et al. 2004). In discussions of South Africa’s biodiversity, it is mostly the country’s flora that is recognized as being of enormous conservation value, followed by the variety of large mammals and rich bird fauna that form the basis of a large ecotourism industry. The contribution of the insect fauna to the country’s biodiversity, in terms of both richness and functioning, is less well known among the public, decision makers and even some conservation scientists. Insect conservation can be considered a relatively new and possibly also a neglected discipline in South Africa, but there has certainly been some progress through various activities, at both landscape and species levels. The future of insect conservation in South Africa faces both challenges and opportunities, most of which are shared with other parts of the world with high and irreplaceable biodiversity.

The leaf-litter earthworm fauna (Annelida : Oligochaeta) of forests in Limpopo Province, South Africa : diversity, communities and conservation

ABSTRACT A qualitative survey of the leaf-litter earthworm fauna of 11 selected indigenous forests in Limpopo Province, South Africa, was conducted to identify the species present, to describe the communities and to assess the relationship between indigenous and exotic species. A total of 8185 individuals from 17 species (five indigenous and 12 exotic species) were recorded. The average earthworm community comprised fewer than five species, but up to seven species were sampled from a single forest. Four of the species recorded are national (one species), regional (one species) or local (two species) endemics. Because these species are not known to live elsewhere, the protection of Limpopo Province forests is critical to their survival. The majority (71%) of the earthworm species sampled was exotic, and differences between exotic and indigenous species richness in forests were mostly significant. At the two spatial scales examined (20 m2 and individual forest) there is no evidence of an association between exotic and indigenous species richness. However, we cannot assume that exotic earthworms do not impact the forest ecosystem.

Effect of burn area on invertebrate recolonization in grasslands in the Drakensberg, South Africa

ABSTRACT Our study examined the short-term response of grassland invertebrate communities to fire in the South African Drakensberg, in relation to distance from the edge of a burn. We aimed to establish which species survive fire and the dynamics of the post-fire recolonization process, and thereby contribute to establishing the ideal area of a prescribed burn for invertebrate conservation. Four transects were sampled two and 12 weeks after burning. Along each transect one unburnt control and four burnt sites were quantitatively sampled. Richness, abundance and diversity were calculated for each site and canonical correspondence analysis was applied to transect and morphospecies counts to determine the impact of distance from the edge of the burn on community structure. Distance from burn edge affected invertebrate richness and abundance, especially for flying insects. Burning appeared to minimally impact on wingless invertebrates, suggesting they tolerated fire by finding refuge. Invertebrate community structure changed with increasing distance from burn edge two weeks, but not 12 weeks post-burn. A distance of 280 m from burn edge appears to allow sufficient recolonization to maintain invertebrate diversity. Taxa found in the unburnt control and site closest to the edge in burnt grassland may be fire sensitive and require further study.

Is Millipede Taxonomy Based on Gonopod Morphology Too Inclusive? Observations on Genetic Variation and Cryptic Speciation in Bicoxidens flavicollis (Diplopoda: Spirostreptida: Spirostreptidae)

ABSTRACT The structure of the male gonopods of millipedes has been considered to be species-specific. As such, gonopods—which aid in copulation and sperm transfer—are used in the taxonomic diagnosis and description of species. However, it was recently demonstrated that gonopod morphology is not always characteristic of species. Diagnoses based on gonopod morphology can therefore result in underestimation of taxonomic diversity amongst millipedes. On the basis of this observation, we examined genetic variation in two populations (approximately 250 km apart) of a widely distributed and colour-polymorphic southern African millipede, namely Bicoxidens flavicollis Attems, 1928. An analysis of genetic divergence based on 520 nucleotides of the mitochondrial cytochrome oxidase 1 gene, and 684 nucleotides of the mitochondrial 16S rRNA gene, demonstrated high levels of divergence (19.09% for cytochrome oxidase 1 and 6.66% for 16S rRNA) between the two populations. These results suggest the presence of cryptic species in B. flavicollis and, furthermore, corroborate observations that taxonomy based on gonopod morphology may be too inclusive.

Two new species of Metabranchipus Masi, 1925 (Anostraca: Branchipodidae)

Two new species of fairy shrimp, Metabranchipus rubra and Metabranchipus prodigiosus, are described from KwaZulu-Natal in South Africa. Both species are separated from M. patrizii by the form of the male second antennae. Metabranchipus prodigiosus is readily separable from all other fairy shrimp by the presence of a large, bifurcated, prehensile appendage that originates between the gonopod bases in the males, and an armored gonopore in the females. The male exhibits the most elaborate amplexial morphology ever observed within Anostraca, whereas the female has no complimentary amplexial specialization, combined with an armored gonopore. We suggest that M. prodigiosus is engaged in a sexual arms race, wherein the females are under selection to avoid mating. The history of Branchipodidae is discussed. The seven branchiopodid genera are reviewed and a key is provided, with a checklist of the described species.

African Invertebrates in the International Year of Biodiversity

The United Nations declared 2010 to be the International Year of Biodiversity to celebrate biodiversity, increase understanding about how biodiversity is critical for sustaining life on Earth, and to highlight the ongoing and increasing loss of biodiversity. The emphasis of this campaign is on people and biodiversity, and the monetary value of biodiversity in terms of goods and services, rather than the traditional focus on saving iconic threatened species and ecosystems. The change in emphasis away from species conservation may seem misdirected; we monitor biodiversity by tracking the number of species that have gone extinct and by the number of threatened species, species make up ecosystems, which provide people with services, and species are di-

Patterns of millipede (Diplopoda), centipede (Chilopoda) and scorpion (Scorpionida) diversity in savanna habitats within the Greater Makalali Conservancy, South Africa

ABSTRACT Although savanna is one of the most important biomes in southern Africa, it is, apart from the botanical component, one of the least studied. This study aimed to document the distribution patterns, richness and diversity of selected ground-dwelling, flightless arthropods (millipedes, centipedes and scorpions) within savanna habitats to improve invertebrate conservation planning. Five habitat types (white sand bushveld, brown sand bushveld, general mixed bushveld, rocky outcrops and mopane woodland) within the Greater Makalali Conservancy, Limpopo Province, South Africa, were studied using four successful sampling methods (active searching of two types of quadrats, pitfall traps and drive transects) during three sampling periods between February 1999 and March 2000. Millipedes were consistently the most species rich and abundant taxon. Species were not uniformly distributed across all habitat types; some species were unique to certain habitats. Generally, the more heterogeneous habitats supported the greatest millipede, centipede and scorpion diversity, richness and density, and in the case of the millipedes contained the highest number of regional endemics and habitat specialists. There was no significant difference in scorpion diversity among habitats.

Do cytochrome c oxidase 1 Gene Sequences Differentiate Species of Spirostreptid Millipedes (Diplopoda: Spirostreptida: Spirostreptidae)?

ABSTRACT The aim of this study was to use cytochrome c oxidase 1 (CO1) sequences to recover a phylogeny for seven morphologically described spirostreptid millipede taxa from southern Africa, and to evaluate the correspondence between morphological and molecular phylogenies. Genetic p-distance generally increased with taxonomic divergence: inter-specific mean 15.33 % (14.09 % –17.02 %), inter-generic mean 18.43 % (6.83 %–26.81 %) and inter-order mean 24.16 % (range 18.56 %–30.77 %). Congruent Bayesian, maximum parsimony and neighbour-joining analyses of 520 nucleotides of the CO1 gene resolved the orders Spirostreptida, Julida and Callipodida. Members of genera within the Spirostreptidae (Archispirostreptus, Bicoxidens, Cacuminostreptus, Doratogonus, Orthoporoides, Plagiotaphrus and Spirostreptus) formed a single clade within which a sample of Thyropygus (family Harpagophoridae) was paraphyletically nested. Phylogenetic analyses failed to recover support for the genera Doratogonus, Bicoxidens, Archispirostreptus and Spirostreptus, as representatives of these genera were not monophyletic. Samples morphologically identified as the same species (Bicoxidens flavicollis) were part of two different clades, one of which was well supported and otherwise contained members of Doratogonus. This high level of divergence (mean 12.64 %) between morphologically identified spirostreptid millipede sister species could indicate that changes in genital morphology occur rather slowly relative to CO1 sequence substitution, and may underestimate species diversity.