Snake communities of moist rainforest and derived savanna sites of Nigeria: biodiversity patterns and conservation priorities

The taxonomic composition and the abundance of two communities of snakes were studied in two different areas of southern Nigeria. One community was studied in a derived savanna area (environs of Ejule, 06°54N, 07°23E), and one community was studied in a moist rainforest area (environs of Eket, 04°50N, 07°59E). Both the specific diversity and the mean frequency of observation of snakes were significantly higher in the forest area than in the savanna area, and the dominance index was higher in the savanna than in the forest site. However, most of the species were found in only one of the two areas, depending on their habitat requirements (e.g. Gastropyxis smaragdina, Dispholidus typus, Thelotornis kirtlandii, Dendroaspis jamesoni, Bitis nasicornis, Causus maculatus, etc). The forest community housed a significant number of arboreal and semiaquatic taxa, but in both sites most of the species were terrestrial. The commonest species in the forest area was an oviparous, semiaquatic, batracophagous natricine snake (Afronatrix anoscopus), whereas the commonest species in the savanna area was an oviparous terrestrial lacertophagous psammophine snake (Psammophis phillipsi). Some conservation implications of our biodiversity analyses are presented. It is suggested that the moist rainforest represents a critically endangered habitat, and should deserve special attention by the international scientific community. Oil industry activity is especially dangerous for snake communities, especially in the southernmost regions of Nigeria.     

Life history adaptations of phyllopods in response to predators,vegetation, and habitat duration in north-eastern Natal

Phyllopod populations were monitored in three temporary pools differing in the amount of submerged, peripheral vegetation present, surface area and duration. The effects of these factors on the life history strategies employed by phyllopods were investigated. Triops granarius, various conchostracan species and the anostracan Branchipodopsis sp. inhabited the periphery of two pools where rooted, submerged vegetation was abundant while three Streptocephalus species dominated the central, unvegetated regions of the pools and the unvegetated pool. This distribution pattern appeared to be related to the animals' morphology and feeding habits. The peripheral regions of the pools were stressful habitats since they were colonized by large numbers of predators and competitors 30–40 days after inundation and they dried out sooner than the centre. The peripheral species exhibited typical r-selected life history strategies; they grew rapidly, reproduced early and had short lifespans and in this way they overcame the threats presented by their habitat. The central species took advantage of their predator-free, more stable habitat and exhibited life history patterns which tended towards the K-end of the r-K continuum. A degree of intraspecific variation in growth and reproduction was obvious and appeared to be related to differences in habitat duration of the three pools.     

Distribution, habitat characteristics and conservation requirements of a forest-dependent threatened invertebrate Lissotes latidens (Coleoptera: Lucanidae)

The distribution, habitat and conservation requirements of an endangered stag beetle, Lissotes latidens (Coleoptera: Lucanidae), in south-east Tasmania were investigated. This study trebled the known range of the species to 280 km², of which 15% constituted potential habitat. The beetle was found to inhabit a range of wet forest types including damp eucalypt forest, wet eucalypt forest, rainforest and riparian areas amongst drier forest types. Relative to other Tasmanian lucanids, L. latidens was found to occur at quite low population densities. The species had a preference for forest with a well-developed overstorey and greater than 10% ground cover of coarse woody debris (CWD). Although L. latidens is soil-dwelling throughout its life-cycle, it has a close association with CWD, occurring under logs at the interface of soil and CWD. Suitable forest habitat for L. latidens is poorly reserved, with 48% managed under clearfell, burn and sow forestry regimes; a practice that is likely to lead to the depletion of CWD over successive harvesting rotations. Recommendations are made for the conservation management of habitat utilised by L. latidens in off-reserve areas. The need for conservation strategies to incorporate the temporal dynamics of habitat important to forest-dependent threatened species is discussed.     

Chemically-mediated interactions in benthic organisms: the chemical ecology of Crambe crambe (Porifera,Poecilosclerida)

Five temporary forest pools at Noxubee National WildlifeRefuge,Noxubee Co., Mississippi were surveyed monthly for three yearstogain a better understanding of the dynamics of temporaryaquatichabitats. The objective of this study was to characterize thephysicochemical and biological changes in temporary pools inorderto assess the temporal habitat diversity. These ecosystems,allwithin no more than 4 km of one another, were heterotrophicwith adetrital-based food web derived from allochthonous leaflitter.These pools were chosen because of their close proximity tooneanother, they historically filled and dried seasonally, andtheywere known breeding sites for resident amphibian populations.Only47% of the amphibian cohorts inhabiting the pools appeared tothrive and metamorphose prior to pool desiccation. Successfuldevelopment and dispersal of larvae was variable among poolsandyears. We found that the filling cycles differed amonghabitats andthat physiochemical and biological parameters were highlyvariable.Our data suggest that ephemeral pools in this central piedmontregion of Mississippi are each unique and represent habitatsof lowpredictability for amphibian breeding and success. We concludethatit is erroneous to draw generalizations regarding a typicaltemporary pool ecosystem within this region.     

Synthesis of Gal-β-(1→4)-GlcNAc-β-(1→6)-[Gal-β- (1→3)]-GalNAc-α-OBn oligosaccharides bearing O-methyl or O-sulfo groups at C-3 of the Gal residue: specific acceptors for Gal: 3-O-sulfotransferases

Our recent studies have revealed the existence of two distinct Gal: 3-O-sulfotransferases capable of acting on the C-3 position of galactose in a Core 2 branched structure, e.g., Gal14GlcNAc16(Gal13)GalNac1OBenzyl as acceptor to give 3-O-sulfoGal14GlcNAc13(Gal13)GalNAc1OB 20 and Gal14GlcNAc16(3-O-sulfoGal13)GalNAc1OB 23. We herein report the synthesis of these two compounds and also that of other modified analogs that are highly specific acceptors for the two sulfotransferases. Appropriately protected 1-thio-glycosides 7, 8, and 10 were employed as glycosyl donors for the synthesis of our target compounds.     

The importance of urban reserves for conserving beetle communities: a case study from New Zealand

Urban reserves provide a major opportunity for conservation of indigenous biodiversity in the heavily urbanised landscape of Waitakere City (Auckland), New Zealand. However, there is little documented information on what indigenous fauna survives in these reserves. Beetle (Coleoptera) communities associated with two small, isolated urban reserves and two sites in a larger forest area within the Waitakere Ranges were sampled using pitfall traps and analysed. A total of 887 beetles, from 23 families and 89 recognisable taxonomic units were caught. The urban reserves had a marked reduction in species richness and abundance of beetles compared with the sites within the larger forest areas. Various environmental factors influencing the distribution of beetles across the sites were investigated. The most important factors were size of fragment, local forest cover and soil moisture. Common species (>5 specimens in the total dataset) found in the Waitakere Ranges and small urban reserves, were either endemic or indigenous to New Zealand. Therefore, even though these reserves may be isolated from a larger, more continuous forest tract, they have considerable potential as reservoirs of beetle diversity in highly modified landscapes and the contribution of urban reserves to the local sustainability of beetle assemblages emphasises the importance of maintaining green areas in and around cities.     

Ecophysiological studies in Kalanchoë porphyrocalyx (Baker) and K. miniata (Hils et Bojer), two species performing highly flexible CAM

Preceding results, based on the determination of stable carbon isotope composition (₁₃C) of leaf tissues from various Kalanchoë species, suggested a close coincidence between the photosynthetic flexibility of the species and their habitat, life form and taxonomic position within the genus. The ability to shift from C₃-to Crassulacean Acid Metabolism (CAM)-type of photosynthesis seemed to concern in particular the more ancestral species in the genus and to be linked to epiphytism and changing climatic situations. For deeper insights into these interrelationships, physiological studies in controlled conditions were carried out on K. miniata and K. porphyrocalyx. These two species differ by their habitat preference and life form. Measurements were conducted on CO₂ exchange patterns, day/night fluctuation of malate content in the leaves and capacity of phosphoenolpyruvate carboxylase (PEPC). The results show that the 2 species can be considered as facultative CAM plants, with very high flexibility in their photosynthetic behaviour. The decrease in water availability seems to be a major factor triggering the shift from C₃ to the CAM mode. In K. miniata, 21 days of drought depressed CO₂ uptake to the level of CAM idling whereas in K. porphyrocalyx, CO₂ exchange was considerably more resistant. At least for K. miniata, short-day treatment was found to be a further CAM-inducing factor. The results are discussed in terms of their ecophysiological significance under the environmental conditions of the sites where the investigated species naturally grow.     

Testing for non-randomness in sizes and habitats of West Indian lizards: choice of species pool affects conclusions from null models

Summary Several null models are proposed for testing whether size or habitat differences in West IndianAnolis lizards are greater than expected by chance. The models differ primarily in choice of the pool from which species are sampled to form random communities. Regardless of choice of pool, size differences in the Lesser Antilles are greater than null models predict; the pool using species on the known source (Puerto Rico) gives a greater variance in ratios but about the same mean ratio (for males), or a greater mean ratio (for females), compared with the pool composed of species on the islands being tested (the Stronget al., 1979, Galápagos procedure). On satellite islands of the Greater Antilles, sizes do not differ more than expected from null models. Pools composed of mainland-source species give null communities with more small or more large ratios than those composed of island species, depending upon whether four-species islands are included or excluded, respectively. Colwell and Winkler's unmodified Narcissus hypothesis is contradicted by these results in procedures where species not likely to be able to occur on small islands are included in the species pool. Using the most biologically reasonable, but not other, choices of source pool, species on satellite islands of the Greater Antilles differ more in structural habitat then expected by chance. In contrast to some of the results on size, here mainland-source pools are more likely to produce a statistically significant difference between real and random communities, as predicted by the Narcissus hypothesis. However, exclusion of structural habitat categories not found on satellite islands is necessary to achieve this significance.     

Plant distribution in relation to the length of the growing season in a snow-bed in the Taisetsu Mountains,northern Japan

The distribution pattern of plants was studied in an alpine snow-bed in six plots along a snow-melting gradient. Each plot consisted of two habitats with respect to the microtopography; the flat habitat and the mound habitat. The number of species per plot decreased with the shortened snow-free period. In the flat habitat, the dominant growth forms changed from the early exposed plots to the late exposed ones as follows; lichens evergreen and deciduous shrubs forbs graminoids bryophytes. In the mound habitat, evergreen and deciduous shrubs prevailed widely along the gradient because of the ability to exploit new habitat by creeping over exposed rocks. For shrubs, the existence of mounds contributed to the expansion of the distribution ranges. Forbs and graminoids shifted their distribution modes to the late exposed plots where shrubs decreased in cover. Deciduous shrubs and forbs completely disappeared in the latest exposed plot.     

Tree diversity change in remaining primary mixed-broadleaved Korean pine forest under climate change and human activities

Studying biodiversity change in existing typical ecosystems of the world under possible global climate change and local human activities is important for diversity conservation. An adapted forest dynamics model is used to simulate tree diversity change of the remaining primary mixed-broadleaved Korean pine forest (RPMKPF) in northeast China under global climate change and local human activities for the next 50 years. Human activities include logging, which removes all big trees (DBH > 50 cm), removing all individuals of each single species and all species of each functional type (shade tolerant, shade intolerant and medium type tree species). As results for RPMKPF, the index of tree diversity decreases under climate change, but it increases significantly under a combination of climate change and logging. Removing all individuals of each single species significantly affects the tree diversity of the ecosystem. After the removal of shade tolerant species, both and _c indices of tree diversity experience a significant change. The index decreases significantly under climate change when shade intolerant or medium type tree species are removed, but the _c index does not change significantly. The results of this study have implications for tree diversity management in RPMKPF under climate change and human activities.     

Integrating local plant resources and habitat management

The use of wild plant resources as a source of basic needs is an important aspect of multiple-use of land in much of Africa, ranging from vegetation with a low species diversity, high biomass production and resilience to harvesting (e.g.Phragmites reedbeds,Cymbopogon grasslands) through to vegetation with a high diversity of species (and plant life-forms), with a multiple of uses and often low resilience to resource harvesting (e.g. medicinal plants, pole cutting, fuelwood from Afro-montane forest). Complexity and costs of managing sustainable use of wild populations increase markedly with an increasing number of uses and resource users. It is suggested that if the primary objective of core conservation areas is accepted to be the maintenance of habitat and species diversity, then the limited money and manpower available for management of core conservation areas in southern Africa limits sustainable harvesting use of plant resources to low diversity, low conservation priority vegetation types or encroaching species. For high diversity, high conservation priority sites such as Afro-montane or Coastal evergreen forest, the emphasis must be on providing alternative sources of supply to resource users outside of core areas. Botanical gardens staff, with their horticultural experience, can play a very important role through bulking up material for supply to small farmers, herbalists and introducing additional species for agro-forestry. Botanical gardens can play a greater role in the establishment of field gene banks andex situ conservation of vulnerable species. They can also provide a valuable educational and research role on mass production techniques to boost local stocks of threatened and commercially valuable species for cultivation by local people, whether farmers or specialist users (e.g. herbalists) in the country of origin as a means of generating employment and restoring local self-sufficiency.     

Phytochrome dependent decrease of gibberellin-sensitivity

Exogenous gibberellin removes the genetical suppression of mesocotyl elongation in dark-grown seedlings of the rice cultivar Nihon Masari (japonica type). This gibberellin effect can be cancelled by light. All light effects can be accounted for by phytochrome. Dose-response and fluence-response studies show that phytochrome induces a reduction of the sensitivity to exogenous gibberellins. A cytological analysis of cell elongation and cortical microtubules led to a model where gibberellin and red light regulate mesocotyl elongation by controlling microtubule orientation in the epidermis of the mesocotyl. This causes corresponding changes of cellular extension growth, which can account for a large part of the observed growth responses. Comparative studies involving antimicrotubular drugs and gibberellin-synthesis inhibitors in the rice cultivar Kasarath (indica type) and a hybrid cultivar suggest that some of the differences between the cultivars are due to differences in gibberellin-sensitivity.     

Developing regional conservation priorities using red lists: a hypothetical example from the Swiss lowlands

This paper investigates how different prioritizations of species for conservation can affect both the number of breeding individuals that receive protection and the distribution of conservation attention among different types of habitat. I use as a study example three red lists of the avifauna of Kanton Zürich in northern Switzerland. Species are weighted based on their placement in different red list categories to represent differences in species' relative conservation value. I examine how these weightings affect the number of breeding pairs benefiting from increasing conservation effort. Conservation effort is defined as the number of ranked land parcels that receive conservation attention, be it through habitat enhancement, protection, or other measures. I rank parcels' conservation value based on the number of weighted breeding pairs estimated for each parcel. Not surprisingly, the number of category-1, -2 and -3 breeding pairs that receive benefits varies greatly when different red lists are used. Changes in the relative conservation value of species in different categories influences both the number of breeding pairs and the number of parcels to receive conservation attention. The effect of increasing conservation effort on the number of breeding pairs and the proportion of each landscape type receiving attention also vary when different red lists and relative conservation values are used to determine conservation priorities. Use of the official red list published by a governmental body (Bundesamt für Umwelt, Wald und Landschaft, Bern, Switzerland) results in more emphasis on conservation in agricultural landscape than did use of either of the other two lists. The process of prioritization of sites for conservation should evaluate the effects of variation in both the relative conservation value of species and species categorization that may arise due to incomplete data and variation in opinion.     

Antiphonal duetting in Steere’s liocichla (Liocichla steerii): male song individuality and correlation between habitat and duetting behavior

We studied duet song and vocal duetting behavior in an endemic Taiwanese passerine, Steeres liocichla (Liocichla steerii). We found that the leading male song in duets was highly individualistic. Also, we found duetting behavior varied significantly across different habitat types. Females were more likely to answer male songs in densely vegetated, steep forest habitat compared to open agricultural habitat. These findings provide quantitative evidence for vocal individuality for a duet song and provide tentative support for the idea that females are duetting to reveal their location to their mates.     

Forest Fragment and Breeding Habitat Characteristics Explain Frog Diversity and Abundance in Singapore

Habitat loss and fragmentation can have severe negative and irreversible effects on biodiversity. We investigated the effects of forest fragmentation on frog diversity in Singapore because of its high rates of deforestation and the demonstration that frogs are some of the most sensitive species to habitat degradation. We surveyed frog species in 12 forest fragments varying from 11 to 935 ha. We compared differences in species richness, abundance, and Shannon's index in relation to forest fragment size, connectivity (distance between fragments), and breeding habitat heterogeneity. A total of 20 species from 12 genera and five families were encountered in 12 fragments. Larger fragments and those closer to larger fragments had higher species richness. Abundance, however, was not correlated with forest area or connectivity, but we found fewer individual frogs in the larger fragments. We also found that breeding habitat heterogeneity best explained frog species diversity and abundance in forest fragments. Fragments with a high diversity of breeding habitats had more species. We found no evidence to suggest that abundance and diversity are strongly correlated, particularly in disturbed areas, but that breeding habitat heterogeneity is an under-appreciated factor that should be considered when prioritizing areas for anuran conservation. Enriching breeding habitat heterogeneity, creating corridors between fragments, and reforesting degraded areas are some of the most beneficial strategies for preserving urban frog biodiversity.     

Evaluation of an exotic maize population adapted to a locality

Summary An exotic Zea mays L. population (Tuxpeno) was adapted to North Carolina conditions by first introducing genes for adaptability from two North Carolina varieties ([(Jarvis X Indian Chief)Tuxpeno]Tuxpeno) including four generations of intermating, and then selecting for adaptability using maturity as the primary measure. The study evaluated selection for adaptability and the diversity available between adapted Tuxpeno and the local varieties, Jarvis and Indian Chief. Analytical procedures were developed to quantify the diversity between populations and the complementation of local varieties by introduced germ plasms. The analyses utilized the specific effects available from the diallel mating design.Three replicate selections responded similarly under simple recurrent mass selection (1/10) for the earliest disease-free plants initially and additionally for plant types (primarily height) in the final generation. The 1/4 local germ plasm permitted rapid adaptation of Tuxpeno gene pool to local conditions. The adapted Tuxpeno populations yielded similarly to the local populations with an average heterosis for grain yield of 28% when crossed to the local populations used as source of genes for adaptability. The diversity found between adapted Tuxpeno lines and these local varieties based on genes affecting grain yield was 1.5 to 2.5 times that measured between the local varieties (Jarvis and Indian Chief). Diversity lost through intergradation with local material was a reasonable investment. Yield genes introduced from Tuxpeno complemented local gene pools through nonadditive, primarily dominance-associated, gene effects. Reassortment of major gene blocks apparently occurred leading to significant divergence among replicate selections involving both additive-associated and dominance-associated gene effects.Paper No. 6355 of the North Carolina Agri. Res. Ser., Raleigh, NC. Research supported in collaboration with the Rockefeller Foundation and CIMMYT, D.F. (Mexico)     

Macrofaunal diversity and habitat structure in intertidal boulder fields

Low-midshore boulder fields in Europe are increasingly subject to degradation related to beach fishing for crabs and abalones. The aim of the study was to better understand the structure and species diversity of macrofaunal assemblages living in a low-midshore boulder field in order to define conservation strategies for this biotope. Sampling strategy involved different spatial scales (macro- and microstrata) relative to the complexity and heterogeneity of the habitat. Assemblages of species and the corresponding habitats were identified by multifactorial analysis and compared by ANOVAs. The results show a hierarchical organization of the macrofauna within the boulder field, corresponding to three spatial levels of habitat structure: (i) eight microhabitats at the lowest level of spatial organization, each defined by a specific assemblage (subcommunity); (ii) three habitats at a middle level combining these microhabitats, each associated with a specific community (open rock, protected rock and sediment); and (iii) three macrohabitats at the uppermost level (corresponding to the scale of the entire boulder field and including the main geomorphological features of the beach), each defined by a specific assemblage of species (boulders on boulders, boulders on bedrock, and boulders on sediment). Two microhabitats with particularly high species diversity were regarded as the most important ecological units of the field in terms of conservation of specific and functional biodiversity. Comparison of habitat/community parameters showed (i) that habitat heterogeneity was not an accurate indicator of faunal diversity, and (ii) that habitat complexity enhanced the species richness of the fauna, but only above a threshold value. This enhancement was due to semi-sheltered microhabitats, which were found only in the most complex areas of the boulder field. It is likely that this complexity affects species richness qualitatively more than by the diversity of microhabitats. In other words, a cross-scale effect is apparent in which high habitat complexity on the middle spatial scale creates microhabitats on the lowest spatial scale that are characterized by stable semi-sheltered environmental conditions conducive to a maximum of species.     

Fruiting studies in species ofCapronia (Herpotrichiellaceae)

A recently described protocol for thein vitro production of ascomata was employed to determine the sexual incompatibility systems of five species ofCapronia. The formation of mature ascomata in isolates derived from single ascospores demonstrated thatC. epimyces, C. mansonii, andC. munkii n. sp. are homothallic. In contrast, fertile ascomata were observed only in mass-ascospore isolates and pairwise crosses between specific single-ascospore isolates inC. dactylotricha n. sp. andC. moravica. TheExophiala anamorphs ofC. dactylotricha andC. munkii are described and aPhialophora-like synanamorph is reported for the former species. Germinating ascospores ofC. munkii formed conidiogenous cells directly, while the ascospores of the remaining species germinated to produce germ tubes and hyphae. The application of the terms microcyclic conidiation to secondary conidium production and sclerotial body and stroma to the multicellular structures produced by species ofCapronia andExophiala are discussed.     

RFLP markers to identify the alleles on the Mla locus conferring powdery mildew resistance in barley

Summary To identify the mildew resistance locus Mla in barley with molecular markers, closely linked genomic RFLP clones were selected with the help of near-isogenic lines having the Pallas and Siri background. Out of 22 polymorphic clones 3 were located around the Mla locus on chromosome 5 with a distance of 5.1 + 2.9 cM (MWG 1H068), 4.2±1.7 cM (MWG 1H060) and 0.7 ± 0.7 cM (MWG 1H036), respectively. The polymorphic clone MWG 1H036 displayed the same RFLP pattern in both Pallas and Siri near-isogenic lines and in different varieties digested with six restriction enzymes possessing the same mildew resistance gene. The alleles of the Mla locus were grouped in 11 classes according to their specific RFLP patterns; 3 of these groups contain the majority of Mla alleles already used in barley breeding programs in Europe.     

Effects of competition and N and P supply on carbon isotope discrimination and <Superscript>15</Superscript>N-natural abundance in four grassland species

The effect of interspecific competition and element additions (N and P) on four grassland species (Poa pratensis, Lolium perenne, Festuca valida, Taraxacum officinale) grown under field conditions was studied. Two grasses (L. perenne, F. valida) grown in monoculture (absence of competition) showed lower carbon isotope discrimination (¹³C) and enriched ¹⁵N values. Nitrogen addition (as urea) had inconsistent effects on species ¹³C while caused enrichment of ¹⁵N of P. pratensis and F. valida but strong depletion of ¹⁵N of T. officinale. Phosphorous had no significant effect on ¹³C but depleted ¹⁵N of all species.