Consequences of a large-scale fragmentation experiment for Neotropical bats: disentangling the relative importance of local and landscape-scale effects

Context

Habitat loss, fragmentation and degradation are widespread drivers of biodiversity decline. Understanding how habitat quality interacts with landscape context, and how they jointly affect species in human-modified landscapes, is of great importance for informing conservation and management.

Objectives

We used a whole-ecosystem manipulation experiment in the Brazilian Amazon to investigate the relative roles of local and landscape attributes in affecting bat assemblages at an interior-edge-matrix disturbance gradient.

Methods

We surveyed bats in 39 sites, comprising continuous forest (CF), fragments, forest edges and intervening secondary regrowth. For each site, we assessed vegetation structure (local-scale variable) and, for five focal scales, quantified habitat amount and four landscape configuration metrics.

Results

Smaller fragments, edges and regrowth sites had fewer species and higher levels of dominance than CF. Regardless of the landscape scale analysed, species richness and evenness were mostly related to the amount of forest cover. Vegetation structure and configurational metrics were important predictors of abundance, whereby the magnitude and direction of response to configurational metrics were scale-dependent. Responses were ensemble-specific with local-scale vegetation structure being more important for frugivorous than for gleaning animalivorous bats.

Conclusions

Our study indicates that scale-sensitive measures of landscape structure are needed for a more comprehensive understanding of the effects of fragmentation on tropical biota. Although forest fragments and regrowth habitats can be of conservation significance for tropical bats our results further emphasize that primary forest is of irreplaceable value, underlining that their conservation can only be achieved by the preservation of large expanses of pristine habitat.

     

Growth, Survival, and Feed Conversion Rates of Hatchery-Reared Mutton Snapper Lutjanus analis Cultured in Floating Net Cages

Abstract.— The aquaculture performance of mutton snapper Lutjanus analis raised in floating net cages was assessed by measuring their growth, survival, and feed conversion rates during a growout trial conducted in a 3.2‐ha saltwater lake in the Florida Keys, Florida, USA. Approximately 10,500 hatchery‐reared finger‐lings were stocked in two circular, high‐density polyethylene (HDPE) net cages of 7‐m diameter × 7‐m deep (300 m²) and 10‐m diameter × 7‐m deep (600 m³) dimensions. Cages were stocked at 25 fish/m³ (3.2 kg/m³) and 5 fish/m³ (0.72 kg/m³), respectively. Fish grew from a mean of 16.5 g to 302.8 g (25.6 cm TL) in 246 days in the former cage and from a mean of 42.3 g to 245.6 g (23.8 cm TL) in 178 d in the latter cage. Growth rates in weight were best expressed by the following exponential equations: cage 1 (high stocking density): W = 20.716 e^0.0112x (r²= 0.83); cage 2 (low stocking density): W = 38.848 e^0.0118x (r²= 0.81). Length‐weight data indicate that hatcheryraised, cage‐cultured mutton snapper are heavier per unit length than their wild counterparts. There was no significant difference (P < 0.05) between the slopes of the two lines, indicating that fish in the two cages grew at the same rate. The length‐weight relationships for mutton snapper stocked in cages 1 and 2 are expressed, respectively, by the equations W = 0.000009 L ^3.11 (r²= 0.99) and W = 0.000005 L ^3.22 (r²= 0.97). Overall feed conversion rate for both cages combined was 1.4. Approximately 10% of the fish sampled exhibited some degree of deformity, particularly scoliosis. Overall survival rate was 70%. Results suggest that L. analis has potential for aquaculture development in net cage systems.     

Evaluation of the efficacy of prophylactic hoof health examination and trimming during midlactation in reducing the incidence of lameness during late lactation in dairy cows

OBJECTIVE: To assess the efficacy of prophylactic hoof health examination and trimming during midlactation at reducing the incidence of lameness during late lactation in dairy cows. DESIGN: Randomized field trial. ANIMALS: 333 Holstein cows. PROCEDURES: Cows without apparent lameness were randomly allocated into 1 of 2 groups approximately 204 days after calving. Cows allocated to the treatment group (n = 161) were examined on a tilt table for diagnosis and underwent hoof-trimming procedures, if needed, for treatment of hoof disorders or lesions. Cows in the control group (n = 172) were not examined. Cows were assigned a locomotion score weekly for 28 weeks after allocation to a group. The number of cows classified as lame during late lactation (approx 205 to 400 days after calving) was compared between groups to assess the efficacy of prophylactic examination and trimming. RESULTS: Incidence of lameness during late lactation was 24% in cows in the control group and 18% in cows in the treatment group. CONCLUSIONS AND CLINICAL RELEVANCE: The 25% decrease in number of new cases of lameness in cows undergoing prophylactic hoof health examination and trimming during midlactation may be relevant for the well-being of dairy cows and should not represent a major economic burden to producers.     

Evidence for a relationship between bovine erythrocyte lipid membrane peculiarities and immune pressure from ruminal ciliates

Erythrocytes of bovines and other ruminants have a strikingly anomalous phospholipid composition, with low or absent phosphatidylcholine (PC) together with high sphingomyelin (SM) content. Here, we report the presence in normal bovine serum of high levels of anti-phospholipid antibodies of IgM isotype against, PC and the phosphono analogue of phosphatidylethanolamine, aminoethylphosphonolipid (AEPL), normally produced by rumen ciliates. In contrast, no antibodies were detected against SM or N-acyl-phosphatidylethanolamine (NAPE), the major components of bovine erythrocytes. In addition, we found that exposure of the ciliate Tetrahymena thermophila to bovine serum results in rapid lysis, an effect that was inhibited by adsorption of the serum with SM/AEPL liposomes. Furthermore, incubation with bovine serum had a similar effect on freshly obtained ruminal ciliates, and the lytic activity was eliminated by pre-adsorption of the serum with SM/PE liposomes. The ruminant mode of life with its concomitant ciliate fauna is hereby linked to the peculiar conformation of bovine erythrocyte membranes. We propose that the unique phospholipid composition of bovine erythrocytes appears as an evolutionary adaptation to tolerate the lytic effects of anti-phospholipid antibodies generated against AEPL, a membrane component of the huge mass of ruminal ciliates, necessary commensals of this group of mammals.     

Terrestrial Arthropods in the Initial Restoration Stages of Anthracite Coal Mine Spoil Heaps in Northwestern Spain: Potential Usefulness of Higher Taxa as Restoration Indicators

An “edaphic‐landscape” restoration was performed in two anthracite coal mine spoil heaps located in NW Spain as a demonstration and pilot program for the restoration of coal mine spoils. Terrestrial arthropods were used to monitor the process as an alternative to the use of secondary succession of plants or physico‐chemical indicators of soils. This study analyzes the usefulness of the terrestrial arthropods at different taxonomic levels (orders of Arthropoda, families of Coleoptera, and species of Carabidae) as restoration indicators in the initial restoration stages. The terrestrial arthropods respond rapidly to restoration, and the results may be explained by short‐term increase in abiotic factors resulting from the applied techniques, mainly the animal origin of the organic matter added and the biodegradable coconut geotextile. Carabidae is of relatively low value as a short‐term restoration indicator at a specific level. Coleoptera provided the best information for interpreting the ecological results over the short term and had the best relationship with the cost of identification. Likewise, the results showed that the edaphic‐landscape restoration leads to an abnormal arthropod assemblage in the short term because of an excessive abundance of isopods and polydesmids. No clear convergence appeared toward any of the terrestrial arthropod communities present in the grassland, scrubland, or woodland semi‐natural areas, which were used as reference end point. The restoration indicator value produced by the higher taxonomic levels of the studied terrestrial arthropods may be useful and cost‐effective for assessing short‐term changes caused by environmental restorations performed to recover ecosystems affected by mining activities. Copyright © 2014 John Wiley & Sons, Ltd.     

Important considerations in the analysis of generation means

Summary The weighted least squares (WLS) procedure has been widely used in the analysis of generation means in biometrical genetics. Two methods to carry out the analysis have been presented in the literature (Mather & Jinks, 1971; Rowe & Alexander, 1980). Neither method identified the factors that need to be taken into account when deciding which procedure to use. This paper examines the fitting of the additive-dominance model using the general principles of least squares analysis and presents the statistical basis of each procedure. Mather & Jink's method, which is more realistic according to genetic theory, is based on the assumption that the populations have nonhomogeneous variances. Rowe & Alexander's method is based on the assumption that the populations have homogeneous variances. In the latter case, there is actually no need to do a WLS analysis. The ordinary least square analysis using the original observations rather than the means, will produce the regression parameter estimates.     

Effect of incubation temperature regimes and culture medium on broccoli microspore culture embryogenesis

Conditions for reliable induction of embryogenesis from isolated microspores were studied in ten genotypes of broccoli. Embryo yields were significantly increased in almost all of the broccoli genotypes by the incubation at 32.5 ^°C for 1 day, than when the standard incubation at 30 ^°C for 2 days was used. Treatments of 48 hours at 32.5 ^°C produced less than optimal results suggesting that broccoli microspores are more sensitive to high temperatures than those of B. napus. The use of the ¹/₂ NLN-13 medium yielded greater number of embryos than the standard NLN-13. The magnitude of the response to the redution of the concentration of major salts by half in the NLN medium varied with the different genotypes. High embryogenic broccoli cultivars, such as ‘Shogun’, ‘SDB9’, and ‘Green Valiant’, presented a better response to the reduction of the concentration of major salts by half in NLN-13. Reduction never produced a detrimental effect on embryo yield and seems not to have any effect in the subsequent development of embryos in plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sunflower mutant containing high levels of palmitic acid in high oleic background

A new sunflower mutant, CAS-12, was obtained, which has both high palmitic (≈30%) and high oleic acid contents, and also a substantial amount of palmitoleic acid (≈7%). The mutant was selected after X-ray irradiation of dry seeds of the inbred line BSD-2-423, which had normal palmitic (≈3%) and high oleic (≈88%) acid levels. The increase of palmitic and palmitoleic acids occurred at the expense of the oleic acid content, which decreased to around 55% in respect to the original line. Linoleic acid content is always under 5%. Palmitic and palmitoleic acid levels were similar to those of the high palmitic mutant CAS-5 obtained in a previous programme from a low oleic line isogenic to BSD-2-423 using a similar mutagenic treatment. In that previous programme we also selected three high stearic acid mutants using chemical mutagenic treatment on the same sunflower line (RDF-1-532). We attempted to obtain mutants in other lines but were unsuccessful. The isolation of similar mutants in isogenic parental lines illustrates the importance of the genetic background in the development of specific mutants with an altered seed oil fatty acid composition. The oil of this mutant will increase the range of potential uses of sunflower oil. This revised version was published online in July 2006 with corrections to the Cover Date.     

Molecular biology of male gametogenesis

Pollen development has been studied at a molecular level in several systems that are amenable to genetic or transgenic analysis. We have characterized several tomato genes that are expressed late in pollen development. Our goals in this research were 1) to determine the cis- and tran-acting factors that mediate pollen expression, and 2) to determine the functions of the proteins encoded by these genes. We currently favor the hypothesis that pollen-specific gene expression is mediated in a combinatorial manner. Antisense experiments have indicated an important role for the LAT52 protein during pollen hydration.