Subtidal macrozoobenthic community resilience to change following natural mouth breaching of the temporarily open/closed East Kleinemonde Estuary,South Africa

The East Kleinemonde Estuary, on the south-east coast of South Africa, typically opens for only short periods, usually <10 days. During a nine-month study in 2006, marine influence persisted for a near-continuous period of three months. This provided an opportunity to explore potential changes in the structure and pattern of the subtidal estuarine macrozoobenthic community. Salinity changes were minimal after mouth opening, decreasing by c. 4 and 8 in the lower and upper estuary, respectively. Salinity decrease was due to river dominance over tidal influence. Two biotic assemblages, structured by sediment characteristics, typified the community throughout the study: a sand-associated group near the mouth and a mud-associated group upstream. Amphipods were proportionally the most abundant group within each assemblage and on each sampling occasion. At the species level, high variability typified the community, with no trends or patterns observed. However, species richness declined from 27–30 to 23 after mouth opening. The number of species returned to former levels at the time of the final survey and just before final mouth closure. An analysis of the subtidal macrozoobenthos in the East Kleinemonde and other temporarily open/closed estuaries (TOCEs) of similar size in the bioregion indicated that communities were typically composed of relatively few, broadly tolerant euryhaline species with no species unique to TOCEs.     

Efficacy and Safety of Dulaglutide in Hispanic/Latino Patients with Type 2 Diabetes in the Award Clinical Program

Objective: The aim of this post hoc analysis was to assess the efficacy and safety of once-weekly dulaglutide in Hispanic/Latino patients with type 2 diabetes (T2D) in phase 3 AWARD trials 1 to 6.Methods: Hispanic/Latino data at Week 26 were pooled across studies for each dulaglutide dose to analyze the change from baseline in glycosylated hemoglobin (HbA1c), percent to HbA1c goal, and adverse events (AEs). Change from baseline in HbA1c, change from baseline in weight and hypoglycemia were analyzed by Hispanic/Latino and non-Hispanic/Latino subgroups for each study.Results: Of the 3,136 patients randomized to dulaglutide 1.5 or 0.75 mg, 949 were reported as having Hispanic/Latino ethnicity. Baseline characteristics were similar for Hispanic/Latino and overall populations, except there were slightly more Hispanic/Latino females and weight was slightly lower for Hispanic/Latino patients. Hispanic/Latino patients receiving dulaglutide 1.5 mg had a reduction in HbA1c of 1.25% (95% confidence interval [CI]: -1.35, -1.15); dulaglutide 0.75 mg had a reduction of 1.07% (95% CI: -1.18, -0.96). Reductions in HbA1c and percent to goal HbA1c <7% and ≤6.5% were similar between Hispanic/Latino patients and the overall population. Weight change and hypoglycemia were similar between Hispanic/Latino and non-Hispanic/Latino subgroups for all studies. Treatment-emergent AEs were consistent with the overall population.Conclusion: Dulaglutide improved glycemic control with the potential for weight loss in Hispanic/Latino patients with T2D. Dulaglutide was well tolerated and had a low risk of hypoglycemia when used without insulin secretagogues or insulin. In the Hispanic/Latino population, dulaglutide efficacy and safety was consistent with that of the overall population.Abbreviations:AE = adverse eventAWARD = Assessment of Weekly AdministRation of dulaglutide in DiabetesBID = twice dailyCARMELA = The Cardiovascular Risk Factor Multiple Evaluation of Latin AmericaCI = confidence intervalGLP-1 RA = glucagon-like peptide-1 receptor agonistHbA1c = glycosylated hemoglobinT2D = type 2 diabetes     

Foraging theory provides a useful framework for livestock predation management

A societal shift toward plant dominant diets and a reduction in livestock rearing could have broad social, environmental and conservation benefits. Livestock husbandry, however, has a wealthy cultural history, strong support and high consumer demand. It is therefore likely to continue as a major land use and conservation issue for predators. From a producer’s perspective, the primary goals of livestock protection are maximising, or at least maintaining, production by minimising losses and mitigating detriment to stock welfare. Lethal removal of predators remains a commonplace solution. Such management measures are questionable as they raise animal welfare and conservation concerns, risk inhibiting ecological processes, are often expensive, and in some circumstances, exacerbate livestock predation problems. Non-lethal alternatives can facilitate co-existence between livestock farmers and predators, ideally reducing the ecological impact of pastoralism and achieving conservation goals. The need for rigorous study of non-lethal approaches has however been recently highlighted. Tools and methods involved in livestock protection, as well as the theoretical basis of how we perceive and manage the problem, require deeper consideration. Non-lethal approaches require knowledgeable implementation and an effective decision making system is a prerequisite for successful practice. Livestock predation and its prevention are fundamentally influenced by the underlying principles of foraging ecology and risk theory. We propose that manipulating elements of Brown’s (1988) quitting harvest rate model provides a useful conceptual framework for reducing livestock predation and encouraging coexistence.     

A simple chromosomal marker can reliably distinguishes <Emphasis Type="Italic">Poncirus</Emphasis> from <Emphasis Type="Italic">Citrus</Emphasis> species

Several chromosome types have been recognized in Citrus and related genera by chromomycin A₃ (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA⁺ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm. During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars, two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin, we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker.     

Strong genetic isolation despite wide distribution in a commercially exploited coastal shark

The common smoothhound, Mustelus mustelus, is an epibenthic species targeted by fisheries around the world driven by the increasing demand for shark products. Given the wide-spread occurrence of this species and corresponding lack of molecular data in many areas of said distribution, baseline molecular assessments of this commercially important shark may contribute to finer-scale analyses in areas in which this species is targeted. Therefore, population genetic analyses were conducted along the East Atlantic, from the Mediterranean Sea to the south-east coast of Africa, using microsatellite markers and the mitochondrial control region (mtCR). Overall, M. mustelus displayed low to moderate genetic diversity, with the Mediterranean populations appearing to exhibit the lowest mitochondrial diversity, and the west African populations displaying the lowest nuclear diversity. Microsatellite analysis indicated strong genetic differentiation between the three regions, with finer-scale population structure in each region, without correlation between genetic and geographical distance. For the mtCR sequences, a total of 18 haplotypes were identified, with a high degree of divergence discernable between the regions, largely in accordance with the microsatellite data. The study documents a remarkable level of population isolation across a vast area, suggesting little or no present-day connectivity among extant populations. The findings may serve as an essential baseline for global population management and commercial traceability of this threatened shark.

     

Habitat amount hypothesis and passive sampling explain mammal species composition in Amazonian river islands

Nested structures of species assemblages have been frequently associated with patch size and isolation, leading to the conclusion that colonization–extinction dynamics drives nestedness. The ‘passive sampling’ model states that the regional abundance of species randomly determines their occurrence in patches. The ‘habitat amount hypothesis’ also challenges patch size and isolation effects, arguing that they occur because of a ‘sample area effect’. Here, we (a) ask whether the structure of the mammal assemblages of fluvial islands shows a nested pattern, (b) test whether species’ regional abundance predicts species’ occurrence on islands, and (c) ask whether habitat amount in the landscape and matrix resistance to biological flow predict the islands’ species composition. We quantified nestedness and tested its significance using null models. We used a regression model to analyze whether a species’ relative regional abundance predicts its incidence on islands. We accessed islands’ species composition by an NMDS ordination and used multiple regression to evaluate how species composition responds to habitat amount and matrix resistance. The degree of nestedness did not differ from that expected by the passive sampling hypothesis. Likewise, species’ regional abundance predicted its occurrence on islands. Habitat amount successfully predicted the species composition on islands, whereas matrix resistance did not. We suggest the application of habitat amount hypothesis for predicting species composition in other patchy systems. Although the island biogeography perspective has dominated the literature, we suggest that the passive sampling perspective is more appropriate for explaining the assemblages’ structure in this and other non‐equilibrium patch systems. Abstract in Portuguese is available with online material.     

Contribution of adventitious vs initial roots to growth and physiology of black spruce seedlings

Black spruce (Picea mariana [Mill.] BSP) is a boreal tree species characterized by the formation of an adventitious root system. Unlike initial roots from seed germination, adventitious roots gradually appear above the root collar, until they constitute most of mature black spruce root system. Little is known about the physiological role they play and their influence on tree growth relative to initial roots. We hypothesized that adventitious roots present an advantage over initial roots in acquiring water and nutrients. To test this hypothesis, the absorptive capacities of the two root systems were explored in a controlled environment during one growing season. Black spruce seedlings were placed in a double‐pot system allowing irrigation (25 and 100% water container capacity) and fertilization (with or without fertilizer) inputs independent to initial and adventitious roots. After 14 weeks, growth parameters (height, diameter, biomass), physiology (net photosynthetic rate, stomatal conductance, shoot water potential) and nutrient content (N, P, K, Ca and Mg foliar content) were compared. Most measured parameters showed no difference for the same treatment on adventitious or initial roots, except for root biomass. Indeed, fertilized black spruce seedlings invested heavily in adventitious root production, twice as much as initial roots. This was also the case when adventitious roots alone were irrigated, while seedlings with adventitious roots subjected to low irrigation produced initial root biomass equivalent to that of adventitious roots. We conclude that black spruce seedlings perform equally well through adventitious and initial roots, but if resources are abundant, they strongly promote development of adventitious roots.