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Biodiversity research in South Africa: Comments on current trends and methods
Abstract
Biodiversity research is crucial to conservation and sustainable utilization of our fauna. We highlight and discuss four issues: (1) taxa chosen as indicator species, (2) use of morphospecies, (3) sampling techniques and (4) integrative biogeographical and taxonomic work. We illustrate points with examples from our work on millipedes. We emphasize careful planning and interpretation when using indicator species; discourage the use of morphospecies, especially for conservation planning; encourage active sampling, and especially effort quantification; and recommend cladistic biogeography as a sound approach to conservation planning, especially for invertebrates. We reiterate the necessity for a sound taxonomic infrastructure to understand and manage our biodiversity.
... In order to accomplish the aims of the Convention and to determine the biodiversity of different areas, rapid and effective sampling and estimation procedures are required (Colwell & Coddington, 1994). This is especially the case with invertebrate biodiversity assessment, which is rarely considered cost effective (Oliver \ & Beattie, 1996) and is time consuming as a result of the range of sizes, behaviours and microhabitats (Slotow & Hamer, 2000) occupied by these groups. Many different methods have been used to sample invertebrates in various environments, but in most cases there is no standard method for sampling a particular group of invertebrates. ...
... Passive sampling . techniques (pitfall traps and other trapping techniques) have often been preferred in the past as \ they are considered to be repeatable and capture species active outside searching periods (Slotow & Hamer, 2000) such as nocturnal and less common species. However, there are a few drawbacks to using these methods. ...
... However, there are a few drawbacks to using these methods. They do not collect the less mobile species and also collect a large number of species and individuals (Slotow & Hamer, 2000) that may not form part of the group or groups being studied. Time is thus spent sorting the sampled material in order to obtain the species under study. ...
... Invertebrates comprise the majority of species (Ponder and Lunney 1999;Myers et al. 2000), and are critical for ecosystem functioning (Pimentel et al. 1997), but knowledge of species distributions, assemblage patterns and their drivers is lacking (Ward and Larivière 2004). A major constraint is logistics, with surveys of invertebrates being time-consuming and labour intensive (Slotow and Hamer 2000). Furthermore, specialist taxonomic knowledge and expertise are limited (Slotow and Hamer 2000). ...
... A major constraint is logistics, with surveys of invertebrates being time-consuming and labour intensive (Slotow and Hamer 2000). Furthermore, specialist taxonomic knowledge and expertise are limited (Slotow and Hamer 2000). An additional challenge presented by invertebrate conservation is the negative perceptions and attitudes of most members of the public (Kellert 1993). ...
... In general, conservation research is underfunded and there is also a lack of manpower in this field (Slotow and Hamer 2000;Foster-Smith and Evans 2003). The use of volunteers is becoming increasingly common in biodiversity and conservation research globally (see Cousins 2007) and there are several volunteer based projects which have made a significant contribution to conservation biology (e.g. ...
Invertebrate diversity is seldom included in conservation assessments, primarily because information is lacking. Broad surveys may be too costly, difficult or ineffective. Here we assess a ‘shopping basket’ approach, targeting 17 taxa using a range of methods. We sampled 43 one-hectare sites stratified within 560 km2 of heterogenous African savanna. We achieved up to 80% sampling completeness for epigaeic fauna, but generally much lower completeness (around 50%) for plant-dwelling and flying taxa. For the former we identified duplication of methods, and for the latter, addition of methods and increased temporal variation rather than effort would improve completeness. Within a taxon, sampling 75% of species present required, on average, about 784 individuals. When considering the local richness, 75% completeness required about 27 individuals per species, but these figures require validation in other areas. About 58 sites were required to achieve 75% sampling completeness, translating to about one site per 10 km2. The percentage of species sampled only in a particular month ranged between 4% and 46%, with greater temporal effects recorded for flying taxa than for epigaeic ones. The trend was similar for species unique to a particular year, with the most extreme case being 67% of the butterfly species sampled one year not previously recorded. We demonstrated and evaluated the feasibility of a simultaneous multi-taxon survey approach to produce data useful for conservation planning and monitoring. We strongly recommend a quantified approach for surveys and inventories, with details such as specific methods decided based on the biome sampled, and taxonomic expertise available for identification.
... Invertebrates comprise the majority of species (Ponder and Lunney 1999;Myers et al. 2000), and are critical for ecosystem functioning (Pimentel et al. 1997), but knowledge of species distributions, assemblage patterns and their drivers is lacking (Ward and Larivière 2004). A major constraint is logistics, with surveys of invertebrates being time-consuming and labour intensive (Slotow and Hamer 2000). Furthermore, specialist taxonomic knowledge and expertise are limited (Slotow and Hamer 2000). ...
... A major constraint is logistics, with surveys of invertebrates being time-consuming and labour intensive (Slotow and Hamer 2000). Furthermore, specialist taxonomic knowledge and expertise are limited (Slotow and Hamer 2000). An additional challenge presented by invertebrate conservation is the negative perceptions and attitudes of most members of the public (Kellert 1993). ...
... In general, conservation research is underfunded and there is also a lack of manpower in this field (Slotow and Hamer 2000;Foster-Smith and Evans 2003). The use of volunteers is becoming increasingly common in biodiversity and conservation research globally (see Cousins 2007) and there are several volunteer based projects which have made a significant contribution to conservation biology (e.g. ...
Species’ distributions, assemblage patterns and the processes influencing these are poorly understood, and urgently require
study. Use of volunteers to collect data is becoming increasingly common in biodiversity research. We assess the effectiveness
of volunteers sampling terrestrial savanna invertebrates in comparison to experienced researchers, and examine the potential
contribution of volunteers to terrestrial invertebrate surveys. There were relatively few differences in the diversity sampled
by 54 Earthwatch Institute volunteers when compared to expert researchers. The major difference was in the results from the
less spatially constrained method, where experience (microhabitat selection) most affected results, and experienced researchers
performed better both quantitatively (more species sampled) and qualitatively (more unique and rare species). For the more
constrained and less subjective methods, our training enabled the volunteers to quickly equal the experienced experts. Volunteers’
experience in invertebrate research influenced both the researchers’ perceptions of volunteers’ capacity and the actual performance
of the volunteers. This suggests that appropriate training for the methods used can help to improve volunteers’ success with
the sampling. We demonstrated that volunteers collect valid data; for the most part they sample invertebrates as effectively
as a trained researcher, and that using volunteers has enormous direct benefits in terms of volume of work accomplished. For
invertebrate studies using volunteers, we recommend that the subjectivity of the method be minimised, that experience is compensated
for by increasing volunteer effort (two volunteers=one researcher), and that there is close management of volunteers in
the field to ensure ongoing data quality. Volunteers provide a valuable resource to researchers carrying out biodiversity
surveys, but using volunteers to carry out a scientifically sound project is not an easy option, and should only be implemented
when volunteers would make a meaningful contribution and enable an otherwise impossible project.
... However , since species determination s of invertebrates are rarely based on characteristic features apparent to the inexperienced eye, the estimates of morphospecies are likely to be either an under-or over-estim ate of the true level of diversity. Furthermore, juvenile, female and male spiders often look like different species to non-spec ialists, leading to overestimation of diversity for some groups (Slotow and Hamer, 2000 ). Irrespective of these shortcomings it is a technique that is widely used in many groups (McGeoch, 1998;Obrist and Duelli, 2010;Oliver and Beattie, 1996;Pryke and Samways, 2010 ). ...
... However, if this approach is to be used then the same individua l should sort a specific group and will thus become more experienced . If there is no alternative to using morphospecies , then a good knowledge of specific taxonomic characters of each group chosen is essential (Slotow and Hamer, 2000 ). Reference collections and good photographi c records of identified species are essential and should be properly labeled and documented, and voucher specimens lodged at institutions with appropriate curatorial staff. ...
The inclusion of spiders in conservation planning initiatives is confounded by several factors. Surrogates could facilitate their incorporation. In this paper we investigate the performance of a number of surrogate measures, such as higher taxa (genus, family), cross-taxon surrogates that are subsets of the spider assemblages (certain spider families) or non-overlapping groups (woody vegetation and birds), and the use of morphospecies. Birds and woody vegetation were included because they often form the focus of conservation planning initiatives. We assessed the surrogate measures based on their predictive power for species richness and extent to which conservation planning that maximizes representation of the surrogate is effective in representing spider diversity. A measure for the latter is the Species Accumulation Index (SAI). Generic richness as a higher taxon surrogate and the combined richness of the families Thomisidae and Salticidae were the best estimators of total species richness. Based on the surrogacy efficiency criterion, genera and the family Salticidae had species accumulation indices (SAIs) that were significantly larger than 95% confidence intervals of a random curve, while woody vegetation and birds turned out to be poor surrogates for spider diversity. The use of morphospecies as estimators is cautiously supported (adjusted R2 = 0.85, for species richness, SAI = 0.73). The surrogates identified here provide a viable alternative to whole assemblage analysis but should be used with caution. The use of genera is confounded by unstable taxonomy and the difficulty of identifying specimens up to genus level. Geographic location and varying sampling effort between surveys did not have an effect on the surrogate performance of the two spider families, viz. Salticidae and Thomisidae. The former family has seen a flood of recent systematic work, whereas the latter’s taxonomy is fairly well developed. These two families comprise ca. 20% of spider species observed in the Savanna Biome of South Africa and could provide a viable handle on spider diversity in this region.
... Because of limited resources and potential impact on conservation assets, both inventories and monitoring need to be as effective and efficient as possible. It is impossible to sample and identify every species, even in small areas, and this is especially true for the hyperdiverse invertebrates [2]. Invertebrates may be important in terms of their relatively high levels of endemism [3,4], and their responsiveness to environmental change [5] makes them potential indicators for monitoring (e.g. ...
... A stepwise, integrated, approach is necessary to properly identify biodiversity surrogates or indicators [6,15]. The following steps are recommended: (1) a survey using standardised, quantified effort [2,16]; (2) an assessment of potential taxa for use in conservation planning or monitoring [6 and references therein,15]; and (3) a test of the selected indicator taxon for monitoring a particular disturbance [6,15]). Rohr et al. [15] add in the additional dimension of testing which sampling method is most appropriate for a particular chosen taxon. ...
The diversity and complexity of invertebrate communities usually result in their exclusion from conservation activities. Here we provide a step process for assessing predominantly ground-dwelling Afrotemperate forest invertebrates' (earthworms, centipedes, millipedes, ants, molluscs) potential as surrogates for conservation and indicators for monitoring. We also evaluated sampling methods (soil and litter samples, pitfall traps, active searching quadrats and tree beating) and temporal (seasonal) effects.
Lack of congruence of species richness across taxa indicated poor surrogacy potential for any of the focus taxa. Based on abundance and richness, seasonal stability, and ease of sampling, molluscs were the most appropriate taxon for use in monitoring of disturbance impacts. Mollusc richness was highest in March (Antipodal late summer wet season). The most effective and efficient methods were active searching quadrats and searching litter samples. We tested the effectiveness of molluscs as indicators for monitoring by contrasting species richness and community structure in burned relative to unburned forests. Both species richness and community structure changed significantly with burning. Some mollusc species (e.g. Macroptychia africana) showed marked negative responses to burning, and these species have potential for use as indicators.
Despite habitat type (i.e., Afrotemperate forest) being constant, species richness and community structure varied across forest patches. Therefore, in conservation planning, setting targets for coarse filter features (e.g., habitat type) requires fine filter features (e.g., localities for individual species). This is especially true for limited mobility taxa such as those studied here. Molluscs have high potential for indicators for monitoring, and this requires broader study.
... No multitaxa, quantified survey of invertebrates has previously been carried out in Pondoland. Quantified surveys are critical for comparison of areas and for providing future baseline data for monitoring (Lovell et al. 2010;Slotow & Hamer 2000). ...
Mkambati Nature Reserve (NR) falls within the Pondoland Centre of Endemism, which is part of the Maputaland-Pondoland-Albany global biodiversity hotspot. The biodiversity status of this area is based largely on its flora, and the invertebrates are poorly known. The area is under threat from various proposed developments. We surveyed 14 orders in three invertebrate phyla at 26 sites with two main objectives: (1) to assess the fauna in terms of conservation value, and, (2) to identify habitats and sites of conservation concern. From the survey, 3231 samples were sent for identification and 425 species were identified. A minimum of 18 new species were confirmed. Mkambati NR shows exceptional diversity for molluscs (Gastropoda, 51 species), bees (Apoidea, 48 species) and true bugs (Heteroptera, 65 species). At least 43 species collected from the Reserve are South African endemics, 31 have a restricted distribution within South Africa and 18 are only known from the Reserve itself.
Conservation implications: The authors provide the first assessment of the invertebrate fauna of the Mkambati NR, which indicates that it is a rich and important fauna. The results highlight the need to consider invertebrates in other biodiversity assessments in the Pondoland region. In terms of habitats, for both forest and grassland there was a large difference in the invertebrate communities at different sites, even over relatively short distances in grassland; shared habitat attributes clustered sites with more similar communities, for example, rocky ledges or the sea shore. All forest patches are a priority for protection.
... Pressures such as climate change, pollution and urbanisation mean that biodiversity research is becoming increasingly important if we are to manage ecosystem functioning and services such as soil fertility, clean water and waste processing (Naeem et al. 1994; Slotow & Hamer 2000; Crouch & Smith 2011; Hamer 2010). However, global change drivers and their synergistic effects (Millennium Ecosystem Assessment 2005) might cause extinctions of species not even known to science (Essl et al. 2013; Costello et al. 2013). ...
Earthworms are an important component of southern African invertebrate diversity, due both to their influential roles in soil ecosystems, and the relatively large number of species. As of 2010, there were 282 indigenous earthworm species (most endemic) known to South Africa belonging to three families: Microchaetidae, Tritogeniidae and Acanthodrilidae. In addition, 44 introduced species from six families had been recorded. However, earthworms are rarely included in environmental monitoring or conservation programmes—partly because sampling and species identification are difficult and many sampling methods are destructive and/or toxic. In this paper we review the earthworm sampling techniques most commonly used by screening data from a digitised literature collection on South African earthworms and on-line global searches. By examining a case study sampling of three vegetation types, this paper highlights taxonomic challenges and the effort required to properly curate specimens. The study provides recommendations for future sampling and highlights some key priorities for future work on the group. From the literature review in early 2012, it is clear that collection techniques are often insufficiently recorded in published work. A total of 10 938 publications from the period 1950 to 2012 were found from the literature search and digitised collection and from these only 32 papers recorded the sampling methodology (mainly hand sorting) for South African research, pointing to the need to adopt standard sampling and reporting protocols. We also tested two of the most popular methodologies in the field. Sampling was conducted in January and February 2012 at four sites, with 24 plots at each site (12 digging and 12 using mustard extraction). A total of 2 094 earthworms collected could be assigned a species name, with introduced species predominating at both disturbed and natural sites. It took a team of three to five people digging and hand collecting all earthworm specimens encountered in a plot of 50 cm × 50 cm × 20 cm deep around 45 to 60 minutes. However, much more time was spent curating and identifying samples. While we recommend following the ISO (ISO11268-3, ISO23611-1) protocol for collecting introduced taxa, to get a complete inventory of South African earthworms a range of sampling techniques will be required; in particular, a large 1 m × 1 m × 20 cm plot is required for many large bodied native taxa, and the collection of giant earthworms will require different approaches. The identification of specimens requires skills that are scarce in the country and so there is an urgent need for training and funding for fundamental work on earthworm taxonomy. An atlasing project could serve as a focal point for future research. In providing some general recommendations based on the long and fruitful history of research on earthworms in South Africa, we are optimistic that a better understanding of the group will help us to both improve our usage of natural resources and provide insights into this vitally important edaphic group.
... Butterflies have been under-represented in large-scale spatiotemporal insect studies globally e.g. [14,16,33], especially in South Africa [34,35]. This is notwithstanding that South Africa is an important area for butterfly biodiversity, containing about 17% of species in sub-Saharan Africa [36], of which half are endemic to South Africa and 19% are of high conservation priority [23]. ...
Wildlife and humans tend to prefer the same productive environments, yet high human densities often lead to reduced biodiversity. Species richness is often positively correlated with human population density at broad scales, but this correlation could also be caused by unequal sampling effort leading to higher species tallies in areas of dense human activity. We examined the relationships between butterfly species richness and human population density at five spatial resolutions ranging from 2′ to 60′ across South Africa. We used atlas-type data and spatial interpolation techniques aimed at reducing the effect of unequal spatial sampling. Our results confirm the general positive correlation between total species richness and human population density. Contrary to our expectations, the strength of this positive correlation did not weaken at finer spatial resolutions. The patterns observed using total species richness were driven mostly by common species. The richness of threatened and restricted range species was not correlated to human population density. None of the correlations we examined were particularly strong, with much unexplained variance remaining, suggesting that the overlap between butterflies and humans is not strong compared to other factors not accounted for in our analyses. Special consideration needs to be made regarding conservation goals and variables used when investigating the overlap between species and humans for biodiversity conservation.
... The most common and often the simplest criterion for reserve selection is the number of recorded species and/or the presence of threatened species. However, to achieve a complete list of species is very expensive and time consuming Reyers and van Jaarsveld 2000) and it is impossible to sample every taxon even in small areas (Slotow and Hamer 2000;Margules et al. 2002). As a possible solution to this, surrogate (signal) species and biodiversity indicators have been often used in conservation and restoration ecology (e.g. ...
Enormous and increasing loss of biodiversity requires evaluation of surrogate taxa as a tool for conservation biology and new reserve selection, in spite of the fact that this approach has become questionable. The aim of this study was to assess the effect of gradient complexity on species richness and community composition among three taxonomic groups. We compared efficiency of vascular plants to indicate diversity of cryptogams (bryophytes, lichens) and snails in two contrasting habitat types (treeless fens and forests) within the same geographic region. We examined correlation of their species richness (Spearman rank correlation), community composition (Bray–Curtis similarity, Mantel test) and their responses to environmental variables (detrended and canonical correspondence analysis). We also focused on Red List species. We found that spatial congruence among studied taxa was affected by habitat type, however vascular plants were good indicator of snail biodiversity in both habitats. Nevertheless, all significant positive correlations of species richness were associated with the congruence in main environmental gradients. Although there was a consistency in significantly positive cross-taxon correlation in community similarity, the congruence was insufficient for conservation purposes. Furthermore we confirmed the necessity of integration of at-risk species in conservation planning as Red List species were poor indicators for total species richness and vice versa. We suggest the complementation of existing reserve network with small-scale protected areas focused on conservation of at-risk ecosystems, communities or species. In this study vascular plants were not found as a sufficient indicator for fine-filter conservation of other taxa.
... @BULLET Conservation, through planning (biogeographic studies, e.g. vanJaarsveld et al. 1998), assessment (e.g.Grimaldi et al. 2000;Rogo & Odulaja 2001) and monitoring (e.g.Agosti et al. 2000;McGeoch 1998;Slotow & Hamer 2000). @BULLET Ecosystem function: there are recent reviews of savanna studies at Lamto, Côte d'Ivoire, and elsewhere in Bourlière (1983) and Lamotte (1990), but much more research needs to be undertaken on insect rôles. ...
... Invertebrates perform essential ecosystem functions, yet they are largely overlooked in mainstream conservation planning (Huntly et al. 2005), largely as a consequence of generally poor taxonomic data. More data will certainly contribute to the inclusion of invertebrates in biodiversity conservation planning (Slotow & Hamer 2000 ). The challenge is to cover as much of the poorly sampled areas in Africa as possible to overcome collecting bias and, more importantly, to achieve this in the face of the current accelerated rate of development in Africa (Hamer & Slotow 2002). ...
The millipede genus Zinophora (Chamberlin, 1927) was previously revised based on the species present south of the Zambezi and Kunene Rivers. Since that revision, two additional new species have been discovered and are here described: Zinophora lobata (Mozambique) and Z. taromberai (Zimbabwe and Tanzania). This brings the total number of described species in the genus to 21. An updated key to species in the genus is presented. Detailed illustrations of the gonopods supplement the descriptions and a distribution map of Z. taromberai in Zimbabwe is provided. There appear to be up to three species groups in the genus and the character states defining these groups are discussed.
... In other instances, local and regional biogeographic analyses are not carried out (Cowling 2002) owing to lack of adequate data. In this context the question arises whether it is mandatory to ensure that the full complement of all plants growing in a particular area has been recorded or whether using indicators may be adequate (eg Balmford 1998; Reid 1998; Slotow and Hamer 2000 ). Although biogeographic analyses based on incomplete data are carried out in many parts of the world (eg Lovett et al 2000), whether or not these analyses provide a fair reflection of the true situation has not yet been tested. ...
Despite its importance for tourism and rural development, the biogeographic status of semi-desert and savanna transition inselbergs and mountains in central Namibia is poorly known. This study therefore investigates 11 inselbergs and their mountain flora in the central Namib Desert with regard to biogeographic patterns. Variation between seasons in variable environments is one of the most critical factors biasing global biodiversity analyses, and often results in lack of biogeographic analysis in these areas altogether. This study shows that patterns in floristic measures were largely maintained when a subset of the data was analyzed that contained only perennial plants (which are visible at these sites also during a poor rainy reason). This approach may hence be adapted in other areas that experience similar problems in data coverage related to seasonal differences.
... To evaluate these intuitive statements, to judge the method and to estimate the quality of data, I will compare the outcome of parataxonomic sorting with the results of taxonomic identification of the same samples. Some comparative data have been published (Cranston and Hillman 1992; Oliver and Beattie 1993, 1996a, 1996b; Wagner 1996; Trueman and Cranston 1997; Pik et al. 1999; Slotow and Hamer 2000; Derraik et al. 2002), and I added some more from recent projects (Table 1). The common parameter that has been used to judge the quality of sorting is the error, which is defined as number of taxonomically identified species minus number or parataxonomic units (PUs), and this result is divided by the species number (Oliver and Beattie 1993). ...
Parataxonomic sorting of samples to recognizable taxonomic units (RTUs, morphospecies, morphotypes or, as proposed here: parataxonomic units [PUs]) is generally considered to be a sufficiently reliable and conservative approach in ecological biodiversity studies or conservation biology. It is obviously time-saving because it avoids the burdens of taxonomy. However, evaluations of parataxonomic sorting by taxonomic resorting show many overestimations of species numbers. Hence, RTU sorting is not necessarily conservative. Sorting errors can be more than 100% (median in the present compilation: 22%). Even if the cumulative results for diverse groups like beetles have a very low overall error, the error rate in the single families is generally much higher. This pattern is likely to cause severe problems in multivariate analyses. The presumable error rate in sorting does not depend only on the group to be sorted, but also on the sorter and the sample. Therefore, the sorting error is not predictable. Since PUs are generally neither described nor assigned to existing names, the sorting results are difficult to check and it is mostly not revealed why the samples are sorted as they are. Since parataxonomy does not use existing biological knowledge, creates typological units and does not disclose its sorting criteria, inter-subjective testability and falsifiability of the sorting results are more difficult than of taxonomic identifications (or are even impossible). Parataxonomy does not fulfil the criteria of a scientific method, but is propedeutic and can be a heuristically valuable tool to find out patterns in taxonomically neglected groups. However, it is only the first step in sorting and identifying samples in biodiversity studies. PUs are useless for inventories and area selection in conservation evaluation, biogeographical and autecological studies; they provide only uncertain data for studies in species turnover and overlap, but they can be used quite reliably for global comparisons of gross species richness, non-comparative descriptions of species richness of single sites or for comparisons of sites without species overlap. If results of parataxonomic sorting show clear and biologically meaningful patterns, the sorting is likely to be reliable. Weak or no detectable patterns may easily be caused by erroneous sorting.
Taxonomic sufficiency has received increasing attention in studies aimed at monitoring the effects of disturbances on terrestrial arthropod communities. The main objective was to prove that the community structure of epigaeic arthropods analyzed at different taxonomic resolutions can distinguish the ecosystems studied. Epigaeic arthropods were sampled with pitfall traps in six Peruvian coastal desert ecosystems in the province of Pisco (Ica, Peru). The ability to distinguish ecosystems was compared among orders, families and species, using three types of multivariate analyzes (NMDS, cluster, ANOSIM) and three similarity indexes (Raup-Crick, Bray-Curtis, Morisita-Horn). Also, additional analyses were performed to characterize the data matrices and to measure the relationship of community structure with the main environmental gradient (aridity). The results were: 1) the community structure of epigaeic arthropods analyzed at different taxonomic resolutions distinguished ecosystems included in the study area, 2) the aggregation of data matrices is a process that improves the application of multivariate analysis, 3) the community structure of epigaeic arthropods analyzed at different taxonomic resolutions was related to the main environmental gradient in the study area. These results are compared with findings from previous studies and some suggestions for future studies are made.
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 m2 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.
Conservation planning in the Cape Floristic Region, a recognized world plant diversity hotspot, required systematic (i.e. presence/absence) information on the estimated distributions of the medium-to large-sized mammals. A pragmatic approach for obtaining distribution estimates, for the period prior to arrival of European settlers, was employed. Distribution estimates were based on a combination of a literature survey (with emphasis on early texts) and the ecological requirements of species, and were mapped within each of 102 Broad Habitat Units delineated according to key biophysical parameters. The estimated distributions of 42 species are provided in the form of maps; these are accompanied by brief notes on historical and current occurrences. The distributions, which can be used to guide conservation decisions, should be considered as testable hypotheses.
We present the assessment of the land snail diversity in approximately 50 km2 of savanna/forest mosaic in the northern part of Lopé National Park, Gabon, taking into account habitat variation and seasons. A total of 3,745 specimens were collected, yielding 74 species from 12 families, with Subulinidae being the most speciose family. Most specimens were not identified but assigned to Recognizable Taxonomic Units. Extrapolations suggest that the true diversity of the area lies between 79 and 132 species. Overall snail abundance was low, and most species were minute. Spatial and habitat heterogeneity was high, with 33.8% of the species collected from one station only. Rare species made up a considerable proportion of the fauna, with 23.0% of the species represented by one specimen only. The most species-rich habitats were mature forest, Marantaceae forest, rocky forest, and forest fragments isolated in savanna, in that order. Savanna was the least species-rich habitat, and no species were confined to this habitat. Benefits and drawbacks of the Recognizable Taxonomic Units approach are discussed, and suggestions for maximizing mollusc inventories in tropical forests are proposed.
Biodiversity is presently a minor consideration in environmental policy. It has been regarded as too broad and vague a concept to be applied to real-world regulatory and management problems. This problem can be corrected if biodiversity is recognized as an end in itself, and if measurable indicators can be selected to assess the status of biodiversity over time. Biodiversity, as presently understood, encompasses multiple levels of biological organization. In this paper, I expand the three primary attributes of biodiversity recognized by Jerry Franklin — composition, structure, and function—into a nested hierarchy that incorporates elements of each attribute at four levels of organization: regional landscape, community-ecosystem, population-species, and genetic. Indicators of each attribute in terrestrial ecosystems, at the four levels of organization, are identified for environmental monitoring purposes. Projects to monitor biodiversity will benefit from a direct linkage to long-term ecological research and a commitment to test hypotheses relevant to biodiversity conservation. A general guideline is to proceed from the top down, beginning with a coarse-scale inventory of landscape pattern, vegetation, habitat structure, and species distributions, then overlaying data on stress levels to identify biologically significant areas at high risk of impoverishment. Intensive research and monitoring can be directed to high-risk ecosystems and elements of biodiversity, while less intensive monitoring is directed to the total landscape (or samples thereof). In any monitoring program, particular attention should be paid to specifying the questions that monitoring is intended to answer and validating the relationships between indicators and the components of biodiversity they represent.
Despite concern about the effects of tropical forest disturbance and clearance on biodiversity,, data on impacts, particularly on invertebrates, remain scarce. Here we report a taxonomically diverse inventory on the impacts of tropical forest modification at one locality. We examined a gradient from near-primary, through old-growth secondary and plantation forests to complete clearance, for eight animal groups (birds, butterflies, flying beetles, canopy beetles, canopy ants, leaf-litter ants, termites and soil nematodes) in the Mbalmayo Forest Reserve, south-central Cameroon. Although species richness generally declined with increasing disturbance, no one group serves as a good indicator taxon for changes in the species richness of other groups. Species replacement from site to site (turnover) along the gradient also differs between taxonomic groups. The proportion of `morphospecies' that cannot be assigned to named species and the number of `scientist-hours' required to process samples both increase dramatically for smaller-bodied taxa. Data from these eight groups indicate the huge scale of the biological effort required to provide inventories of tropical diversity, and to measure the impacts of tropical forest modification and clearance.
Invasive plants and plantations may be detrimental to native, ground-living, invertebrate fauna. Using pitfall traps at 20 sites in Pietermaritzburg, South Africa, an assessment was made of the distribution of epigaeic fauna under stands of the exotic invader plants: Acacia longifolia (long-leaved wattle), Acacia mearnsii (black wattle), Lantana camara (lantana) and Solanum mauritianum (bugweed), and also under a canopy of two major plantation trees: Eucalyptus grandis and Pinus patula. Control plots were minimally disturbed grassland and woodland in the same area. The effects of the invasive and cultured plants suggest that the impact is a complex interaction of factors. In general, there was a lower (but not significantly so) species richness, and also diversity, of invertebrates in exotic compared with indigenous vegetation. Certain individual species rather than whole families were affected most by these types of vegetation. There was a different assemblage of species associated with exotic compared with indigenous vegetation, with some species being good indicators for exotic or for indigenous vegetation. Although the weeds and vegetation caused a few species to increase in abundance, many other species decreased or even disappeared locally. Whereas different species assembled according to whether vegetation was exotic or indigenous, families and orders assembled along a gradient of closed to open canopy vegetation irrespective of origin. Although a few species were restricted to exotic vegetation (presumably having invaded at some time in the past from somewhere apart from the control sites), many others were restricted to indigenous vegetation. Vegetation management should be sensitive to the needs of certain invertebrate species so as to conserve them when native vegetation is replaced by exotics. Some management recommendations for conserving local invertebrate diversity are made.
We investigated three procedures that may lead to rapid and accurate assessment of epigaeic arthropod biodiversity. They are: (1) the identification of taxa whose diversity is correlated with that of others; (2) the identification of times and methods of sampling that produce estimates of diversity representative of more intensive sampling; and (3) the use of morphospecies inventories generated by non-specialists. Ants, beetles, and spiders were sampled from four forest types, in three seasons, using two collecting methods: pitfall trapping and extraction from litter. Specimens were sorted by a non-specialist to morphospecies and by specialist taxonomists to species. Richness (alpha-diversity) and turnover (beta-diversity) were compared for different sampling regimes using morphospecies and species inventories. We found no significant positive correlations between ant, beetle, and spider species richness but there was a strong negative correlation between ant and beetle richness. For beetles alone, richness within the families Carabidae, Scarabaeidae, and Pselaphidae (i.e., avoiding taxonomically problematic families) was significantly correlated with richness within all other families. Assessment of turnover revealed that: (1) the four forest types contained significantly different assemblages of ants and beetles but not spiders and (2) the four forests were less clearly discriminated using species from the three beetle families Carabidae, Scarabaeidae, and Pselaphidae when compared to species from all beetle families pooled. Analyses of single sampling periods and methods revealed that summer and spring pitfall samples were most representative of more intensive sampling. That is: (1) the richness of ants and beetles in these samples was significantly positively correlated with the richness of all other samples and (2) turnover of beetles and ants among the four forests revealed by summer pitfall samples was similar to turnover using all samples. The three beetle surrogate families recorded by pitfall samples in spring, and to a lesser extent summer, showed significant correlations in richness with all other beetle species recorded in the same samples. However, the assessment of turnover was less accurate when only surrogate families were used. The most accurate and cost-effective assessment of turnover was generated by a summer pitfall sample in which data for ants, carabid, and scarab beetles were combined and analyzed as a single data set. Results were largely consistent regardless of whether species or morphospecies were used, which suggests that monitoring and assessment of terrestrial invertebrate biodiversity may be achieved by the careful use of morphospecies. Our results also suggest those invertebrate taxa, sampling methods, and sampling periods that yield the most consistent and reliable assessment of epigaeic invertebrate biodiversity in Australian temperate hardwood forests. However, empirical studies that follow the protocols discussed in this paper are urgently required in different environments. These studies may point the way to more representative monitoring and assessment of terrestrial biodiversity.
The application of cladistic data is seen as crucial to answering questions regarding the definition, mode of origin and age of historical biogeographic patterns. From the cladograms and distributional data for four groups of afromontane spiders [Microstigmata (Microstigmatidae), the Moggridgea quercina group (Migidae), and the subfamilies Vidoleini and Phyxelidini (Amaurobiidae)] a set of nine disjunct areas of endemism is defined for African and Malagasy forests. Taxonlarea cladograms are combined through a parsimony method to produce a general area cladogram. General conclusions are: (1) Madagascar is related to eastern Africa and/or eastern South Africa rather than being the sister area to all of Africa; (2) eastern South Africa shows affinities with tropical Africa rather than with the nearby Cape region; (3) the Cape region of South Africa is highly distinctive; and (4) the area cladogram is hard to reconcile with historical scenarios involving primarily dispersal or Pleistocene vicariance events, and a Mesozoic origin for parts of the biogeographic pattern for afromontane spiders is possible.
The efficient representation of all species in conservation planning is problematic. Often, species distribution is assessed
by dividing the land into a grid; complementary sets of grids, in which each taxon is represented at least once, are then
sought. To determine if this approach provides useful surrogate information, species and higher taxon data for South African
plants and animals were analyzed. Complementary species sets did not coincide and overlapped little with higher taxon sets.
Survey extent and taxonomic knowledge did not affect this overlap. Thus, the assumptions of surrogacy, on which so much conservation
planning is based, are not supported.
Richness, rarity, endemism and complementarity of indicator taxon species are often used to select conservation areas, which are then assumed to represent most regional biodiversity. Assessments of the degree to which these indicator conservation areas coincide across different taxa have been conducted on a variety of vertebrate, invertebrate and plant groups at a national scale in Britain, Canada, USA and South Africa and at a regional scale in Cameroon, Uganda and the USA. A low degree of spatial overlap among and within these selected indicator conservation areas has been demonstrated. These results tend to suggest that indicator conservation areas display little congruence across different taxa. However, some of these studies demonstrate that many conservation areas for indicator taxa capture a high proportion of non-target species. Thus it appears that indicator conservation areas might sample overall biodiversity efficiently. These indicator conservation areas may, however, exclude species essential for effective conservation, e.g. rare, endemic or endangered species. The present study investigated the value of indicator taxa as biodiversity surrogates using spatial congruence and representativeness of different indicator priority conservation areas. The conservation status of species excluded by the indicator approaches is also assessed. Indicator priority conservation areas demonstrate high land area requirements in order to fully represent non-target species. These results suggest that efficient priority area selection techniques must reach a compromise between maximizing non-target species gains and minimizing land-use requirements. Reserve selection procedures using indicator-based complementarity appear to be approaches which best satisfy this trade-off.
Although the uses and merits of terrestrial insects as indicators have been extensively discussed, there is a lack of clear definition, goal directedness and hypothesis testing in studies in the field. In an attempt to redress some of these issues and outline an approach for further studies, three categories of terrestrial insect indicators, corresponding to differences in their application, are proposed, i.e. environmental, ecological and biodiversity indicators. The procedures in terrestrial insect bioindicator studies should start with a clear definition of the study objectives and proposed use of the bioindicator, as well as with a consideration of the scale at which the study is to be carried out. Bioindication studies are conducted at a variety of spatial and temporal scales within the contest of earth-system processes, but the objectives of the study will largely determine the scale at which it would be optimally conducted. There is a tendency for studies to be conducted below their space-time scaling functions, giving them apparent predictability. The selection of potential indicator taxa or groups is then based on a priori suitability criteria, the identification of predictive relationships between the indicator and environmental variables and, most importantly, the development and testing of hypotheses according to the correlative patterns found. Finally, recommendations for the use of the indicator in monitoring should be made. Although advocating rigorous, long-term protocols to identify indicators may presently be questionable in the face of the urgency with which conservation decisions have to be made, this approach is critical if bioindicators are to be used with any measurable degree of confidence.
Noted 23 genera and 49 species. There was increasing equitability within habitats ranging from young orchard through old orchard and rank grassland to sparse grassland. The dominant species accounted for as much as 95.7% of individuals in the young orchard and as little as 17.6% in sparse grassland. Overall, Pheidole was the dominant genus. In grassland, but not so much in the orchards, there was a 2-dimensional mosaic distribution of ants. At the nominal level, most habitats shared the majority of species, but at the ordinal level the rank sequence of ants varied considerably between habitats. On the basis of ant abundance at the interval level, habitats grouped according to overall physiognomy, and could be arranged in the following general sequence: old orchard, young orchard, rank grassland, sparse grassland; all but the most abundant species were habitat-sensitive. There was a positive correlation between the number of habitats in which an ant occurred and its overall abundance. Trunk banding, which cuts off the ants' nests from the honeydew source in the tree, is ecologically the most appropriate method of management.-from Author
Regional conservation evaluation requires the effective use of available surrogate information, such as that provided by indicator taxa, for estimating the biodiversity represented by candidate protected areas. A recent study demonstrated that accumulating areas individually species-rich for one group of indicator organisms generally did not result in a set containing the areas that were species-rich for other groups. However, the requirement for a species-rich set, and not just individually-rich areas suggests an alternative assessment based on complementary-areas methods, which find a set of areas such that each of the indicator species is represented at least once. A set of areas covering all indicator taxa is assumed to be generally biodiverse. One limitation of this approach is that the set of areas species-rich for an indicator group is likely to represent many other organisms only if the members of the group span a wide range of habitats or environments. This supports the sampling of environmental pattern itself as an alternative strategy for selecting a set of biodiverse areas. Because such a pattern can be inferred from an indicator group, this same sampling strategy may extend the predictive value of such groups. Further, environmental pattern may incorporate additional useful information; for example, abundance information for the indicator taxa may improve predictions when used in this framework. These pattern strategies use the indicator group in a way that does not depend on the usual complementarity criterion in which a set is to be found that represents each indicator species. An example suggests that the complementary-areas approach may not be the best general strategy for using indicator groups in biodiversity assessment. We conclude that the current complementarity paradigm should be replaced by a more general pattern-based approach which views `complementarity' not as a predictor, but as a general property to be predicted.
Attempts to identify priority sites for conserving biodiversity are
greatly hampered by a lack of good data on species' distributions.
Recent work suggests one promising solution might be to use higher-level
taxa (such as genera or families) which might be more easily surveyed,
yet nevertheless still act as reliable surrogates for patterns of
species richness. But evidence justifying this approach comes mostly
from temperate datasets or inventories over enormous areas, and a number
of concerns remain unanswered about the use of higher-taxon richness for
identifying key conservation sites in the tropics, where most diversity
occurs. Here in the first of two papers addressing these points, we
explored congruence between species and higher-taxon richness across
protected areas in Indo-Malaya and the Pacific rim. Our results support
the use of the higher-taxon approach in guiding tropical conservation,
but with certain reservations. In all three groups examined,
higher-taxon richness was quite closely related to species number.
However, the precision with which absolute species richness of reserves
could be predicted from higher-taxon richness was often surprisingly
low, particularly for rich sites where surveying higher taxa rather than
species would save most time. The performance of higher taxa as
surrogates also dropped sharply with increasing taxonomic rank,
resulting in a trade-off between time saved by high-level surveys and
the value of those surveys. Lastly, we found that species richness
within individual higher taxa was potentially as powerful an indicator
of the overall species diversity of a site as the number of higher taxa
it contained.
A major obstacle to conserving tropical biodiversity is the lack of information as to where efforts should be concentrated. One potential solution is to focus on readily assessed indicator groups, whose distribution predicts the overall importance of the biodiversity of candidate areas. Here we test this idea, using the most extensive data set on patterns of diversity assembled so far for any part of the tropics. As in studies of temperate regions, we found little spatial congruence in the species richness of woody plants, large moths, butterflies, birds and small mammals across 50 Ugandan forests. Despite this lack of congruence, sets of priority forests selected using data on single taxa only often captured species richness in other groups with the same efficiency as using information on all taxa at once. This is because efficient conservation networks incorporate not only species- rich sites, but also those whose biotas best complement those of other areas. In Uganda, different taxa exhibit similar biogeography, so priority forests for one taxon collectively represent the important forest types for other taxa as well. Our results highlight the need, when evaluating potential indicators for reserve selection, to consider cross-taxon congruence in complementarity as well as species richness.
SPECIES conservation in situ requires networks of protected areas selected for high conservation interest13. Throughout most of the world, however, there are neither the resources nor the time to carry out detailed inventories for most taxa2,4 before designating protected areas. Site selection (on grounds other than availability) would be easier and more effective if two things were true: (1) habitats that are species-rich for one taxon are also species-rich for others5; and (2) rare1 species occur in, and therefore benefit from the conservation of, species-rich habitats. Diversity (usually, species richness) and the presence of rare species are the most frequently cited criteria for site selection by conservationists68. Here, we use data on British plants and animals held by the Biological Records Centre (BRC)9 and the British Trust for Ornithology (BTO), mapped on a grid of 10 km × 10 km ('10 km squares') to examine the extent to which species-rich areas for different taxa coincide, and whether species-rich areas contain substantial numbers of rare species. The fine scale and high intensity of recording in Britain produces distributional datasets at least as good as and, in most cases, better than those available elsewhere. For Britain at least, we do not find strong support for either proposition. Species-rich areas ('hotspots'10) frequently do not coincide for different taxa, and many rare species do not occur in the most species-rich squares.
The Insecta is the most speciose class in the Animal Kingdom. The insect-plant relationship is the dominant biotic interaction, yet plants have many times the biomass of all animals together. The functional significance of insects is enormous, owing to the large numbers of individuals and great intra-and interspecific variety. Lack of human appreciation of importance, coupled with the general disregard and dislike of insects, is an enormous perception impediment to their conservation. This impediment coupled with the taxonomic impediment (at most only about 7–10% of insects are scientifically described) must be overcome for realistic biodiversity conservation. As it is not possible to know all the species relative to the rate at which they are becoming extinet, it is essential to conserve as many biotopes and landscapes as possible. These would be for typical species and communities, as well as for endemic sinks. It is also essential to preserve speciesdynamo areas as an insurance for future biodiversity. Preserved areas must also be linked by movement and gene-flow corridors as much as possible. Recognition, functional importance, taxic uniqueness, typicalness, genetic variation and important behavioural traits place much more emphasis on qualitative biodiversity conservation than on quantitative approaches. Ecological entomologists play a significant double role, suppressing noxious populations on crops, livestock and other products, while at the same time identifying and using beneficial species. There are well-known inherent and environmental risks with many traditional control methods and high risks with the use of genetically engineered biopesticide baculoviruses. Preservation technologies, where individuals are held in suspended animation, must be developed soon. However, such technologies, as with restoration activities such as site restoration, captive breeding, reintroductions and translocations, all require considerable knowledge and economic iput to be predictably successful. Ecological restoration involves so many biotic and abiotic interactions in even the simplest of communities, that predictiveness under all potential conditions is virtually unattainable. Instead, there should be strong focus on the preservation and conservation of as many, and as large as possible, pristine and near-pristine unique and typical landscapes as soon as possible.
Millipedes were sampled by hand-collecting from plots and by pitfall trapping at three forest sites in central Tasmania. Seven days of pitfall trapping each month over one year was less efficient than four weeks of hand-collecting in autumn, yielding fewer species and fewer specimens per working day in the field. Hand-collecting is likely to provide more accurate data on species diversity and relative abundance for a range of litter invertebrates.
Protecting biological diversity with limited resources may require placing conservation priorities on different taxa. A system of priorities that reflects the value of taxonomic diversity can be achieved by setting priorities such that the subset of taxa that is protected has maximum underlying feature diversity. Such feature diversity of taxon subsets is difficult to estimate directly, but can be predicted by the cladistic/phylogenetic relationships among the taxa. In this study, a simple measure of phylogenetic diversity is defined based on cladistic information. The measure of phylogenetic diversity, PD, is contrasted with a measure of taxic diversity recently developed by Vane-Wright et al. (Biol. Conserv., 55, 1991). In re-examining reserve-selection scenarios based on a phylogeny of bumble bees (Apidae), PD produces quite different priorities for species conservation, relative to taxic diversity. The potential application of PD at levels below that of the species is then illustrated using a mtDNA phylogeny for populations of crested newts Triturus cristatus. Calculation of PD for different population subsets shows that protection of populations at either of two extremes of the geographic range of the group can significantly increase the phylogenetic diversity that is protected.
Article 8 of the Convention on Biological Diversity obliges contracting
parties to establish protected areas for conservation. This can be
achieved in smaller networks of reserves if their design is based on how
well different sites complement one another biologically, rather than on
more commonly used criteria, such as species richness or simple
availability for acquisition,. However, this increase in efficiency
requires species lists for each candidate site, and obtaining such data
can be expensive; for example, a detailed survey of five taxa across
15,000 km2 of forest in Uganda took nearly 100 person-years
and cost about US$1 million,. Here we ask whether investing in such
surveys makes economic sense, or whether conservation agencies would be
better advised to continue following more traditional reserve selection
procedures, at the cost of having to conserve larger reserve networks.