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  • Geertsen Hunter posted an update 2 days, 22 hours ago

    Fungiid corals (Cnidaria Anthozoa Scleractinia) occur at isolated locations scattered throughout the eastern tropical Pacific. They can be reef-associated but are often found on sand and rubble substrata distant from reef coral habitat. Cycloseris curvata is known in this region from the southern Gulf of California, through Mexico, Costa Rica, and Panamá, and with the southern-most populations occurring in the Galápagos Islands, Ecuador. During Archipelago-wide surveys (1988-2019), living individuals of Cycloseris curvata were observed at only two locations, Devil’s Crown (near Floreana Island) and Xarifa Island (near Española Island). The Devil’s Crown population was observed from 1988 to 2017, whereas living individuals in the Xarifa population were observed from 2005 to 2009. In 2012 a death assemblage (dead skeletons) was discovered at Darwin Island, at the northern-most extent of the Archipelago. At Devil’s Crown, visual surveys were performed annually or biennially from 1990 to 2012, with two more surveys in 2017 and 2019. The living Cycloseris curvata population consisted of 15 individuals in 1990 that gradually increased to 78 individuals by 1995. Over 200 individuals were observed in 1996, and high numbers persisted through 1998 with 335 individuals. Live tissue surface area per polyp ranged from 0.5 to 95.0cm2. The population decreased to 112 individuals in 1999 (following warming associated with the 1997-98 El Niño), with further declines to 20 in 2009 (following cooling associated with the 2007 La Niña) and a rebound to 91 in 2012. After a 5y break in data collection, only one individual (28.3cm2) was observed in 2017, and in 2019 none were observed. Although undetected living Cycloseris curvata populations may exist, and renewed recruitment provides some hope for population reestablishment, it is possible that this fungiid coral species is now extirpated from the Galápagos Archipelago.The reefs of Singapore provide an excellent opportunity to study the population dynamics and growth rates of free-living mushroom corals (Fungiidae) under sediment-stressed conditions. Transect surveys at four study sites revealed a total of 11 free-living mushroom coral species-the same 11 species as those found by local studies since the 1980s. The abundance of the four most common species ranged from 1.0 to 68.3 Ind. per 100m2, while their population size-structure showed a common pattern of a higher proportion of small-sized corals than large-sized ones (i.e. positively skewed size-structure), although very few individuals of the smallest-size classes were recorded for any of the four species. A more positively skewed size-structure for each of the four most common species was observed at the reef slope (5-6m depth) than at the reef crest (2-3m depth), possibly due to a slower growth rate caused by light reduction with depth. All the mushroom corals studied exhibited a decline in growth rate with increasing size and weight, indicating determinate growth. Growth rate of each of the four most common species was similar among the study sites, despite variation in environmental conditions. Our results demonstrate species richness stability over the past three decades, suggesting that these free-living mushroom coral assemblages comprise species that are well-adapted to the chronic high sedimentation characteristic of Singapore’s reefs. However, if the paucity of individuals of the smallest-size classes reflects poor recruitment and/or early mortality, there may be some cause for concern. Our robust baseline data can contribute to a long-term monitoring strategy for determination of changes in mushroom coral population dynamics.An unequivocal link exists between human population density and environmental degradation, both in the near field (local impacts) and far field (impacts due to teleconnections). Human population is most widely predicted to reach 9-11 billion by 2100, when the demographic transition is expected in all but a handful of countries. Strongest population growth is in the tropics, where coral reefs face dense human population and concomitant heavy usage. In most countries, >50% will be urbanized but growth of rural population and need for food in urban centres will not alleviate pressure on reef resources. Aquaculture will alleviate some fishing pressure, but still utilizes reef surface and is also destructive. Denser coastal populations and greater wealth will lead to reef degradation by coastal construction. Denser populations inland will lead to more runoff and siltation. Effects of human perturbations can be explored with metapopulation theory since they translate to increases in patch-mortality and decreases inry to frequent claims, no scientific ambiguity exists with regards to the serious threat posed to coral reefs by humankind’s continued numerical increase.Insects face several (environmental) abiotic stressors, including low temperature, which cause the failure of neuromuscular function. Such exposure leads insects toa reversible comatose state termed chill-coma, but the consequences of this state for the organism biology were little explored. Here, the consequences of the chill-coma phase were investigated in two of the main stored product pest species – the red flour beetle Tribolium castaneum (larvae and adults) and the rice weevil Sitophilus oryzae (adults). For this purpose, a series of low-temperature shocks were used to estimate the chill-coma recovery time (CCRT), survival, nutrition and weight gain/growth of T. castaneum (larvae and adults) and S. oryzae, as well as the development of T. selleck castaneum life stages. The relatively long CCRT was characteristic of beetle larvae, at different low-temperature shocks, and CCRT increased with decreasing temperatures and increasing exposure intervals for both pest species. The survival was little affected by the low-temperature shocks applied, but such shocks affected insect feeding and growth. Tribolium castaneum larvae was more sensitive than adults of both insect species. Moreover, the relative consumption and weight gain of S. oryzae adults were lower than those of T. castaneum adults and mainly larvae, while feeding deterrence was not affected by low temperature shocks, unlike food conversion efficiency. Low-temperature shocks, even under short duration at some temperatures, significantly delayed development. The lower the temperature and the higher the exposure period, the more delayed the development. Thus, the physiological costs of chill-coma are translated into life-history consequences, with potential implications for the management of this insect pest species in stored products and even more so on red flour beetles and rice weevils.

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