Spatial analysis of vegetation patterns in southern Western Australia: implications for reserve design

Spatial analysis of vegetation and soil data collected from 64 sites in southern Western Australia suggests that both soil characteristics and geographic distance between sites are important predictors of the floristic resemblance of sites on a regional scale. These two factors are largely independent, a finding that may reflect recent, rapid speciation in the study area postulated in other studies. Spatial patterns of plant guilds suggest geographic replacement, and contingent exclusion may be an important mechanism maintaining species-richness. Existing soil and vegetation maps used to delineate reserve boundaries are found to be accurate, although the soil maps include information on vegetation patterns, independent of information on soil patterns. Within broad vegetation formations, there is some correlation of floristics in mallee stands with soil characteristics. Ordination analysis indicates a soil moisture/nutrient axis. In contrast, there are few important correlations of floristics with soil characters in kwongan (sand heath) or halophytic vegetation. Geographic distance between sites is a much more important factor. The absence of edaphic correlations implies that the observed geographic replacement of species between sites is a historical legacy, the result of recent, rapid speciation in the spatially patchy environment. It is concluded that if reserves in the region are to conserve the flora, especially rare species, the reserve system should include replicates of stands within the same broad formations and soil types at intervals less than 15 km, the minimum scale of resolution of this study.     

An interaction between ricin and calreticulin that may have implications for toxin trafficking

Here we demonstrate that ricin is able to interact with the molecular chaperone calreticulin both in vitro and in vivo. The interaction occurred with ricin holotoxin, but not with free ricin A chain; and it was prevented in the presence of lactose, suggesting that it was mediated by the lectin activity of the ricin B chain. This lectin is galactose-specific, and metabolic labeling with [(3)H]galactose or treating galactose oxidase-modified calreticulin with sodium [(3)H]borohydride indicated that Vero cell calreticulin possesses a terminally galactosylated oligosaccharide. Brefeldin A treatment indicated that the intracellular interaction occurred initially in a post-Golgi stack compartment, possibly the trans-Golgi network, whereas the reductive separation of ricin subunits occurred in an earlier part of the secretory pathway, most probably the endoplasmic reticulum (ER). Intoxicating Vero cells with ricin whose A chain had been modified to include either a tyrosine sulfation site or the sulfation site plus available N-glycosylation sites, in the presence of Na(2)35SO(4), confirmed that calreticulin interacted with endocytosed ricin that had already undergone retrograde transport to both the Golgi and the ER. Although we cannot exclude the possibility that the interaction between ricin and calreticulin is an indirect one, the data presented are consistent with the idea that calreticulin may function as a recycling carrier for retrograde transport of ricin from the Golgi to the ER.     

Edge effects in fragmented forests: implications for conservation

Edges are presumed to have deleterious consequences for the organisms that remain in forest fragments. However, there is substantial discrepancy among recent studies about the existence and intensity of edge effects. Most studies have focused on seeking simplistic and static patterns. Very few have tested mechanistic hypotheses or explored the factors that modulate edge effects. Consequently,studies are very site-specifci and their results cannot be generalized to produce a universal theory of edges. Although estimates of the intensity and impact of edge effects in fragmented forests are urgently required, little can be done to ameliorate edge effects unless their mechanics are better understood.     

Neighbourhood effects in forests: implications for within-stand patch structure

1 MOSAIC, a spatially referenced Markov model was used to show how interactions among trees in a neighbourhood may influence the patch structure of forests. A series of two-species simulations were conducted with neighbourhood strength ranging from neutral (chances of species replacing each other independent of neighbourhood composition) to strong (chance of replacement for each species proportional to neighbourhood composition), and with neighbourhood sizes including 1–50 neighbours.
2 Neighbourhood strength was positively correlated with the degree of patchiness. Very high neighbourhood strength is necessary to form mono-specific patches composed of hundreds of individual trees. Intermediate neighbourhood sizes (5–12 neighbours) led to the most distinct patches where individuals were arranged so that contact between species was minimized.
3 Neighbourhood effects alone are unlikely to lead to large areas (several ha) dominated by one species. However, simulations showed that neighbourhood effects can augment small differences in the environment, resulting in large mono-specific patches.
4 Simulations with 4 and 5 species indicated that groups of species can interact to form spatially distinct communities, starting from a random mixture on a uniform environment. This implies that neighbourhood effects may be responsible for some unexplained variability in studies that attempt to relate environmental parameters to forest composition.
5 Patch structures that develop due to neighbourhood effects are usually not recognized by current vegetation classification schemes or by forest managers, and this lack of recognition could lead to the loss of certain natural spatial structures on forested landscapes.     

Effects of flooding duration on species richness, floristic composition and forest structure in river margin habitat in Amazonian blackwater floodplain forests: implications for future design of protected areas

Rivers in central Amazonia experience annual water-level fluctuations of up to 14m, flooding vast areas of adjacent forest for periods ranging from a few to 270 days per year. At different sites, variation in the duration and type of flooding results in a mosaic of habitats that includes lakes, grasslands, forests, and streams. To study the effects of flood duration on plant species richness and floristic composition, two river margin sites were surveyed on the rivers Jaú and Tarumã-Mirim. Both areas are seasonally flooded by blackwaters, and plots were made at different topographic levels (lower, middle and upper slopes). All woody plants with DBH>5cm were inventoried in five 10 × 40m plots in each of the three topographic levels, which varied in length of flood duration and mean water level. Plant species richness did not vary significantly between topographic levels, but species composition varied substantially. At both study sites, the species composition exhibited distinctive distribution patterns with respect to the three topographic levels and river site. Differences in the distribution of dominant species in both sites probably relate to the ability of species to withstand seasonal flooding, although other edaphic factors associated with the topographic levels may also be important, especially for less-dominant, locally rare, and habitat generalist species. Species composition overlap among topographic levels at the two sites was highly variable ranging from 15% to 43%. Knowledge about the complex pattern of species composition and distributions between and among topographic levels and river sites is important for the preservation of the diverse flora of the blackwater forests and for the creation of future conservation management plans and design of protected areas in this ecosystem that will maintain the biodiversity.     

Non-target impacts of forest defoliator management options: Decision for no spraying may have worse impacts on non-target Lepidoptera than Bacillus thuringiensis insecticides

Management programs for major forest defoliators such as gypsy moths or forest tent caterpillars, and crop pests such as the European corn borer have shifted from broad-spectrum insecticides to more environmentally benign microbial pesticides such as Bacillus thuringiensis (foliage sprays and transgenic toxin expression in plant tissues). Phytochemically resistant host plants and natural enemies have been used as alternative pest management strategies (including generalist tachinid flies such as Compsilura, viruses, microsporidians, and fungi), but all of these have some non-target impacts, as described from literature review. A sequence of lab and field studies were conducted to determine non-target impacts on native Lepidoptera in North America. The conclusions reached are that a decision not to spray Bt pesticides (i.e. to allow defoliation and natural pest outbreaks to run their course) could be as bad or worse for non-target Lepidoptera as the microbial insecticides would be. The important concept that must be maintained is that all pest management programs have some risk of negative non-target impacts, but it is the magnitude and relative importance that will remain the most critical issue for environmental impacts and pest management.     

Larval dispersal and movement patterns of coral reef fishes,and implications for marine reserve network design

Well‐designed and effectively managed networks of marine reserves can be effective tools for both fisheries management and biodiversity conservation. Connectivity, the demographic linking of local populations through the dispersal of individuals as larvae, juveniles or adults, is a key ecological factor to consider in marine reserve design, since it has important implications for the persistence of metapopulations and their recovery from disturbance. For marine reserves to protect biodiversity and enhance populations of species in fished areas, they must be able to sustain focal species (particularly fishery species) within their boundaries, and be spaced such that they can function as mutually replenishing networks whilst providing recruitment subsidies to fished areas. Thus the configuration (size, spacing and location) of individual reserves within a network should be informed by larval dispersal and movement patterns of the species for which protection is required. In the past, empirical data regarding larval dispersal and movement patterns of adults and juveniles of many tropical marine species have been unavailable or inaccessible to practitioners responsible for marine reserve design. Recent empirical studies using new technologies have also provided fresh insights into movement patterns of many species and redefined our understanding of connectivity among populations through larval dispersal. Our review of movement patterns of 34 families (210 species) of coral reef fishes demonstrates that movement patterns (home ranges, ontogenetic shifts and spawning migrations) vary among and within species, and are influenced by a range of factors (e.g. size, sex, behaviour, density, habitat characteristics, season, tide and time of day). Some species move <0.1–0.5 km (e.g. damselfishes, butterflyfishes and angelfishes), <0.5–3 km (e.g. most parrotfishes, goatfishes and surgeonfishes) or 3–10 km (e.g. large parrotfishes and wrasses), while others move tens to hundreds (e.g. some groupers, emperors, snappers and jacks) or thousands of kilometres (e.g. some sharks and tuna). Larval dispersal distances tend to be <5–15 km, and self‐recruitment is common. Synthesising this information allows us, for the first time, to provide species, specific advice on the size, spacing and location of marine reserves in tropical marine ecosystems to maximise benefits for conservation and fisheries management for a range of taxa. We recommend that: (i) marine reserves should be more than twice the size of the home range of focal species (in all directions), thus marine reserves of various sizes will be required depending on which species require protection, how far they move, and if other effective protection is in place outside reserves; (ii) reserve spacing should be <15 km, with smaller reserves spaced more closely; and (iii) marine reserves should include habitats that are critical to the life history of focal species (e.g. home ranges, nursery grounds, migration corridors and spawning aggregations), and be located to accommodate movement patterns among these. We also provide practical advice for practitioners on how to use this information to design, evaluate and monitor the effectiveness of marine reserve networks within broader ecological, socioeconomic and management contexts.     

A synthesis of genetic connectivity in deep‐sea fauna and implications for marine reserve design

With anthropogenic impacts rapidly advancing into deeper waters, there is growing interest in establishing deep‐sea marine protected areas (MPAs) or reserves. Reserve design depends on estimates of connectivity and scales of dispersal for the taxa of interest. Deep‐sea taxa are hypothesized to disperse greater distances than shallow‐water taxa, which implies that reserves would need to be larger in size and networks could be more widely spaced; however, this paradigm has not been tested. We compiled population genetic studies of deep‐sea fauna and estimated dispersal distances for 51 studies using a method based on isolation‐by‐distance slopes. Estimates of dispersal distance ranged from 0.24 km to 2028 km with a geometric mean of 33.2 km and differed in relation to taxonomic and life‐history factors as well as several study parameters. Dispersal distances were generally greater for fishes than invertebrates with the Mollusca being the least dispersive sampled phylum. Species that are pelagic as adults were more dispersive than those with sessile or sedentary lifestyles. Benthic species from soft‐substrate habitats were generally less dispersive than species from hard substrate, demersal or pelagic habitats. As expected, species with pelagic and/or feeding (planktotrophic) larvae were more dispersive than other larval types. Many of these comparisons were confounded by taxonomic or other life‐history differences (e.g. fishes being more dispersive than invertebrates) making any simple interpretation difficult. Our results provide the first rough estimate of the range of dispersal distances in the deep sea and allow comparisons to shallow‐water assemblages. Overall, dispersal distances were greater for deeper taxa, although the differences were not large (0.3–0.6 orders of magnitude between means), and imbalanced sampling of shallow and deep taxa complicates any simple interpretation. Our analyses suggest the scales of dispersal and connectivity for reserve design in the deep sea might be comparable to or slightly larger than those in shallow water. Deep‐sea reserve design will need to consider the enormous variety of taxa, life histories, hydrodynamics, spatial configuration of habitats and patterns of species distributions. The many caveats of our analyses provide a strong impetus for substantial future efforts to assess connectivity of deep‐sea species from a variety of habitats, taxonomic groups and depth zones.     

Species-area relations in a New Zealand tussock grassland,with implications for nature reserve design and for community structure

Abstract. A tussock grassland, in Blackrock Reserve, New Zealand, was sampled thoroughly at scales ranging from 0.01 m x 0.01 m to 20 m x 20 m, to investigate species-area relations of relevance to plant community structure, and to offer a pointer to reserve design. In total, 96 species were found. Of the native vascular species among these, 20% were new records for the reserve. For the total and the native vascular flora the observed points fell midway between the Arrhenius and Gleason fitted curves. Cryptogams fitted the Arrhenius model well, with z close to the 0.26 value expected for isolates under Preston's Canonical hypothesis. Extrapolation of the Arrhenius curve to the whole of the New Zealand uplands gave values far too large; the Gleason curve gave values much too low. A General Root model is introduced. It fits the observed species richnesses at various quadrat sizes considerably better than previous models. When biogeographic limitations on species richness are included, extrapolation of the General Root curve accurately predicts the size of the upland flora. This fit, the lack of an asymptote, and the rarity structure, are compatible with a random and individualistic model of community structure. However, there are differences in species-area relation between vascular and cryptogamic plants, which cautions against expecting any universal type of community structure. Extrapolations using the General Root model suggest that if the ideal is a 10 km x 10 km reserve, a reserve one tenth that size would contain 81% of the native species in that ideal, and the present Blackrock Reserve contains 67%.     

Germination of shrub species from Chinese subtropical forests: implications for restoration

• Incorporating native shrubs into restoration projects can improve biodiversity conservation and enhance the sustainability of ecosystem functions. Shrubs grow under different forest canopy structures, having varied microclimatic conditions according to forest type and composition. Currently, there is a lack of information on propagation from seed and planting material availability for the utilization of shrubs in forest restoration.
• In the present study, we evaluated the effects of temperature and light on germination of ten shrub species (Ardisia japonica, Callicarpa cathayana, Callicarpa giraldii var. subcanescens, Deutzia schneideriana, Fraxinus sieboldiana, Hydrangea chinensis, Maesa japonica, Rhododendron simsii, Spiraea japonica var. fortunei and Weigela japonica var. sinica) occurring in subtropical forests in China.
• No seeds of any species germinated in the coolest thermal regime (5/10 °C), while optimal temperature requirements varied from 10/20 °C to 25/35 °C. Seeds of small-seeded species had higher germination percentages in the light treatments, while larger seeds were not photoblastic. There was no relationship between germination in the light and the seed shape index.
• Our results may assist in identification of seed traits and suitable shrub species for restoration in specific forest types, thus aiding native forest recovery of structure and composition. Successful recovery leads to enhanced biodiversity, reestablishment of microhabitats and ecological interactions in the forest understorey.

     

Fruit fall in tropical and temperate forests: implications for frugivore diversity

There have been few attempts to compare fruit productivity throughout the world, although this is indispensable for understanding the global variations in frugivore diversity. The purposes of this study are (1) to reveal the patterns in fruit fall in tropical and temperate forests, (2) to examine the environmental factors (location, climate, and total litterfall) affecting these patterns, and (3) to assess the effect of fruit fall on frugivore diversity by using bird and primate data. Fruit fall was compared among 53 forests, from around the equator to the cool-temperate zone at 62°N, in Asia, Africa, North and South America, and Australia. Average ± SD of fruit fall (kg/ha/year) was 454 ± 258 in tropical, and 362 ± 352 in temperate forests. Fruit fall was exceptionally high in Australia (812 ± 461). When Australia was excluded, fruit fall significantly decreased with increasing absolute latitude and altitude, and fruit fall in tropical forest was 1.7 times larger than that in temperate forests (265 ± 227). Total litterfall affected fruit fall significantly, explaining 32, 28, and 64% of the variations of fruit fall in the entire data, tropical data, and temperate data, respectively. The fruit fall/litterfall ratio did not differ between temperate and tropical forests but was significantly higher in Australia than in other regions. Among climatic parameters (annual temperature, precipitation, actual evapotranspiration), a positive relationship was found between temperature and fruit fall in the entire dataset and within temperate forests. Fruit fall seemed to explain the temperate/tropical difference in frugivorous primate diversity to some extent, but not for frugivorous bird diversity. This study shows that the difference in fruit fall in tropical and temperate forests is smaller than that in frugivore diversity, and that it could explain at least part of the frugivore diversity.     

Aminophospholipids have no access to the luminal side of the biliary canaliculus: implications for thr specific lipid composition of the bile fluid

About 95% of the bile phospholipids are phosphatidylcholine. Although the fractions of phosphatidylcholine and of both aminophospholipids phosphatidylserine and phosphatidylethanolamine in the canalicular membrane are in the same order of about 35% of total lipids, both aminophospholipids are almost absent from the bile. To rationalize this observation, we studied the intracellular uptake of various fluorescent phospholipid analogues and their subsequent enrichment in the bile canaliculus (BC) of HepG2 cells. Diacylaminophospholipid analogues but not phosphatidylcholine analogues became rapidly internalized by an aminophospholipid translocase (APLT) activity in the plasma membrane of HepG2 cells. We observed only low labeling of BC by diacylaminophospholipids but extensive staining by phosphatidylcholine analogues. In the presence of suramin, known to inhibit APLT, a strong labeling of BC by diacylaminophospholipid analogues was found that declined to a level observed for control cells after removal of suramin. Unlike diacylphosphatidylserine, diether phosphatidylserine analogue, which is not an appropriate substrate of APLT, accumulated in the BC. The correlation between low labeling of BC and an APLT-mediated transbilayer movement suggests the presence of an APLT activity in the canalicular membrane that prevents exposure of aminophospholipids to the bile.     

Generating conservation kernels to select areas to control red fox (Vulpes vulpes): Potential implications for pest management practice in state forests

Summary In Australia, controlling introduced predators across large areas is unlikely to be successful without careful consideration of the predator's ecology, the economics of the control exercise and the distribution of the taxa to be protected from the predator. Inadequate strategic planning in pest control is commonplace and there is a need for better methods for determining where, when and how to control predators. The present paper describes a method (currently being introduced into planning programmes) of using areas of high prey species integrity (conservation kernels) to identify strategically optimal areas for predator control (particularly Red Fox, Vulpes vulpes ), across broad landscapes. These landscapes are selected using a geographical information system and a combination of predictive habitat models and records of threatened species at risk of predation by the Red Fox, to identify sites of biological wealth. We propose this method as a first step in developing a strategic predator control plan.     

Antibody modeling: implications for engineering and design

Our understanding of the rules relating sequence to structure in antibodies has led to the development of accurate knowledge-based procedures for antibody modeling. Information gained from the analysis of antibody structures has been successfully exploited to engineer antibody-like molecules endowed with prescribed properties, such as increased stability or different specificity, many of which have a broad spectrum of applications both in therapy and in research. Here we describe a knowledge-based procedure for the prediction of the antibody-variable domains, based on the canonical structures method for the antigen-binding site, and discuss its expected accuracy and limitations. The rational design of antibody-based molecules is illustrated using as an example one of the most widely employed modifications of antibody structures: the humanization of animal-derived antibodies to reduce their immunogenicity for serotherapy in humans.     

Drug-DNA recognition: energetics and implications for design

In this article we review thermodynamic studies designed to examine the interaction of low molecular weight ligands or drugs with DNA. Over the past 10 years there has been an increase in the number of rigorous biophysical studies of DNA-drug interactions and considerable insight has been gained into the energetics of these binding reactions. The advent of high-sensitivity calorimetric techniques has meant that the energetics of DNA-drug association reactions can be probed directly and enthalpic and entropic contributions to the binding free energy established. There are two principal consequences arising from this type of work, firstly three-dimensional structures of DNA-drug complexes from X-ray and NMR studies can be put into a thermodynamic context and the energetics responsible for stabilizing the observed structures can be more fully understood. Secondly, any rational approach to structure-based drug design requires a fundamental base of knowledge where structural detail and thermodynamic data on complex formation are intimately linked. Therefore these types of studies allow a set of general guidelines to be established, which can then be used to develop drug design algorithms. In this review we describe recent breakthroughs in duplex DNA-directed drug design and also discuss how similar principles are now being used to target higher-order DNA molecules, for example, triplex (three-stranded) and tetraplex (four-stranded) structures.