RESUMO
Scientists and managers rely on indicator taxa such as coral and macroalgal cover to evaluate the effects of human disturbance on coral reefs, often assuming a universally positive relationship between local human disturbance and macroalgae. Despite evidence that macroalgae respond to local stressors in diverse ways, there have been few efforts to evaluate relationships between specific macroalgae taxa and local human-driven disturbance. Using genus-level monitoring data from 1205 sites in the Indian and Pacific Oceans, we assess whether macroalgae percent cover correlates with local human disturbance while accounting for factors that could obscure or confound relationships. Assessing macroalgae at genus level revealed that no genera were positively correlated with all human disturbance metrics. Instead, we found relationships between the division or genera of algae and specific human disturbances that were not detectable when pooling taxa into a single functional category, which is common to many analyses. The convention to use percent cover of macroalgae as an indication of local human disturbance therefore likely obscures signatures of local anthropogenic threats to reefs. Our limited understanding of relationships between human disturbance, macroalgae taxa, and their responses to human disturbances impedes the ability to diagnose and respond appropriately to these threats.
Assuntos
Antozoários , Alga Marinha , Animais , Humanos , Recifes de Corais , Ecossistema , Alga Marinha/fisiologia , Antozoários/fisiologia , Oceano PacíficoRESUMO
Coral reefs are increasingly affected by a combination of acute and chronic disturbances from climate change and local stressors. The coral reefs of the Republic of Kiribati's Gilbert Islands are exposed to frequent heat stress caused by central-Pacific type El Niño events, and may provide a glimpse into the future of coral reefs in other parts of the world, where the frequency of heat stress events will likely increase due to climate change. Reefs in the Gilbert Islands experienced a series of acute disturbances over the past fifteen years, including mass coral bleaching in 2004-2005 and 2009-2010, and an outbreak of the corallivorous sea star Acanthaster cf solaris, or Crown-of-Thorns (CoTs), in 2014. The local chronic pressures including nutrient loading, sedimentation and fishing vary within the island chain, with highest pressures on the reefs in urbanized South Tarawa Atoll. In this study, we examine how recovery from acute disturbances differs across a gradient of human influence in neighboring Tarawa and Abaiang Atolls from 2012 through 2018. Benthic cover and size frequency data suggests that local coral communities have adjusted to the heat stress via shifts in the community composition to more temperature-tolerant taxa and individuals. In densely populated South Tarawa, we document a phase shift to the weedy and less bleaching-sensitive coral Porites rus, which accounted for 81% of all coral cover by 2018. By contrast, in less populated Abaiang, coral communities remained comparatively more diverse (with higher percentages of Pocillopora and the octocoral Heliopora) after the disturbances, but reefs had lower overall hard coral cover (18%) and were dominated by turf algae (41%). The CoTs outbreak caused a decline in the cover and mean size of massive Porites, the only taxa that was a 'winner' of the coral bleaching events in Abaiang. Although there are signs of recovery, the long-term trajectory of the benthic communities in Abaiang is not yet clear. We suggest three scenarios: they may remain in their current state (dominated by turf algae), undergo a phase shift to dominance by the macroalgae Halimeda, or recover to dominance by thermally tolerant hard coral genera. These findings provide a rare glimpse at the future of coral reefs around the world and the ways they may be affected by climate change, which may allow scientists to better predict how other reefs will respond to increasing heat stress events across gradients of local human disturbance.
Assuntos
Recifes de Corais , Animais , El Niño Oscilação Sul , Estrelas-do-MarRESUMO
PURPOSE: To determine whether follicle curetting at the time of oocyte retrieval increases oocyte yield. METHODS: Retrospective review of all patients who underwent oocyte retrieval from July 1, 2003 to June 30, 2005. MAIN OUTCOME MEASURE: Number of oocytes retrieved. SECONDARY OUTCOME MEASURES: retrieval time, number of cryopreserved embryos, pregnancy rates, and incidence of ovarian hyperstimulation syndrome. RESULTS: There were no differences in patient demographics, antral follicle count, cycle stimulation characteristics, fertilization rates, embryo quantity or quality, embryo cryopreservation rates, clinical pregnancy rates, live birth rates, or ovarian hyperstimulation syndrome between the groups. Retrievals that utilized curetting took three minutes longer. Follicle curetting significantly increased the number of oocytes retrieved, 13.9 +/- 0.6 compared to 11.4 +/- 0.6 oocytes without curetting (P = 0.003). The quantity of mature oocytes was also increased with curetting (10.3 +/- 0.5 versus 8.4 +/- 0.5, P = 0.006). CONCLUSIONS: This study demonstrated that follicle curetting significantly increased oocyte yield. While it did not increase live birth rates, this increase in oocyte yield should lead to increased numbers of embryos for selection at transfer and increased embryos for cryopreservation.
Assuntos
Recuperação de Oócitos/métodos , Oócitos , Folículo Ovariano , Adulto , Feminino , Fertilização in vitro , Humanos , Masculino , Indução da Ovulação , Gravidez , Resultado da GravidezRESUMO
Climate change and human disturbance threatens coral reefs across the Pacific, yet there is little consensus on what characterizes a "healthy" reef. Benthic cover, particularly low coral cover and high macroalgae cover, are often used as an indicator of reef degradation, despite uncertainty about the typical algal community compositions associated with either near-pristine or damaged reefs. In this study, we examine differences in coral and algal community compositions and their response to human disturbance and past heat stress, by analysing 25 sites along a gradient of human disturbance in Majuro and Arno Atolls of the Republic of the Marshall Islands. Our results show that total macroalgae cover indicators of reef degradation may mask the influence of local human disturbance, with different taxa responding to disturbance differently. Identifying macroalgae to a lower taxonomic level (e.g. the genus level) is critical for a more accurate measure of Pacific coral reef health.
Assuntos
Recifes de Corais , Alga Marinha , Animais , Antozoários/fisiologia , Biodiversidade , Meio Ambiente , Humanos , Micronésia , Oceano Pacífico , Alga Marinha/fisiologiaRESUMO
Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages-the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014-2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse.
Assuntos
Antozoários , Recifes de Corais , Animais , Clima , Mudança Climática , Ecossistema , HumanosRESUMO
This study prospectively evaluated the position of the urethrovesical junction using the Q-tip angle to assess early postoperative changes for different anti-incontinence surgeries. All procedures resulted in a statistically significant change in resting angle from the intraoperative value. The mean change for the transvaginal tape was 25.74 degrees (27.43 to 3.28); Burch 11.18 degrees (-20.44 to -10.0) and fascia sling 13.9 degrees (26.57 to 15.68). The mean change in Q-tip angle was greater after transvaginal tape placement than after Burch ( p=0.000) and fascial sling ( p=0.022) procedures. These findings show that the resting position of the urethrovesical junction after surgery is different for all procedures. The transvaginal tape results in the greatest change in angle. This may help to negate the so-called 'tension-free' nature of the procedure. Surgeons need to be aware of this, as it may be an etiological factor in cases of late urinary retention and urethral erosion.