Although there is a continuum in magnitude of diversity loss between the smallest and largest biotic crisis, typically most authors refer to the largest five Phanerozoic events as bmass extinctionsQ. In the past 25 years the study of these mass extinctionevents has increased dramatically, with most focus being on the Cretaceous–Tertiary (K–T) event, although study of the end- Permian event (in terms of research output) is likely to surpass that of the K–T in the next few years. Many aspects of these events are still debated and there is no common cause or single set of climatic or environmental changes common to these five events, although all are associated with evidence for climatic change. The supposed extinction-causing environmental changes resulting from extraterrestrial impact are, at best, equivocal and are unlikely to have been of sufficient intensity or geographic extent to cause global extinction. The environmental consequences of rapid global warming (such as ocean stagnation, reduced upwelling and loss of surface productivity) are considered to have been particularly detrimental to the biosphere in the geological past. The first phase of the Late Ordovician event is clearly linked to rapid global cooling. Palaeoecological studies have demonstrated that feeding mechanism is a key trait that enhances survival chances, with selective detritivores and omnivores usually faring better than suspension feeders or grazers. This indicates that primary productivity collapse and consequent lack of food supply is a key proximate cause of extinction. Typically, this low productivity state continues for several hundred thousand years and is associated with widespread stunting of marine organisms (the Lilliput effect) and low-biomass ecosystems. Rebuilding of the marine ecosystem is an important process, and a number of models have been constructed that can be used for comparative purposes (e.g., to understand variation in rates of recovery between events, or between different regions within the same event). Understanding the extinction and recovery processes in ancient events, especially those associated with global warming, may be crucial to managing the present biodiversity crisis. Yet, as many aspects of these mass extinctionevents remain little understood, there is still much work to do.
Mass extinctionevents punctuate the evolution of marine envi- ronments, and recovery biotas paved the way for major biotic changes. Understanding the responses of marine organisms in the post-extinctionrecovery phase is paramount to gaining insight into the dynamics of these changes, many of which brought sweeping biotic reorganizations. One of the five biggest mass extinctions was that of the end-Triassic, which was quickly followed by phases of recovery in the Early Jurassic. The earliest Jurassic witnessed the loss of conodonts, severe reductions in ammonoids, and reductions in brachiopods, bivalves, gastropods, and foraminifers. Reef ecosystems nearly collapsed with a reduc- tion in deposition of CaCO 3 . Extensive volcanism in the Central Atlantic Magmatic Province and release of gas hydrates and other greenhouse gases escalated CO 2 and led to ocean acidification of the end-Triassic (Hautmann et al., 2008).
Employing the last and ﬁrst appearances of individual taxa to deﬁne
major extinction-related boundaries is dif ﬁcult because commonly
there will be short-term survivors, reworked specimens, fossils repositioned by post-depositional bioturbation, or groups that survived the event in extremely low numbers and appear as Lazarus taxa higher in the geological record. Such taxa can still be valuable subsidiary indi- ces when applying the abundance approach. First appearance data are also inadequate for high-precision location of chronostratigraphic boundaries based on these events because a signi ﬁcant lag-time exists be- tween the extinction event and the evolution of new taxa ( Fig. 9 ). Despite having very different causes, the end-Permian, end-Triassic, and the K –Pg events are consequences of dramatic environmental upheavals that gen- erated comparable extinction patterns, and similar phases of vegetation recovery but at different temporal scales. Based on the observed lag- time for the FADs after such biotic crises, we recommend using relative abundance data for the stratigraphic de ﬁnition of mass extinctionevents and the placement of chronostratigraphic boundaries.
The precise chemical state of the water column also has major implications for the biogeochemical cycling of nutrients such as P and N. Current carbon cycle models for this time period require the inclusion of a positive-feedback mechanism 56,65 , whereby under anoxic conditions P is recycled back into the water column, thereby stimulating further productivity to drive the total organic carbon depositional ﬂux and maintain anoxia 66 . Indeed, the P-feedback mechanism appears to be an essential part of driving global positive CIEs during OAEs 67 . This, however, is less applicable under ferruginous conditions, whereby P is more likely to be sequestered in the sediment during uptake by Fe-(oxyhydr)oxide minerals 68 . The development of euxinia is also closely tied to the N cycle, being dependent on the mode of nitrogen supply to the photic zone 16 . The behaviour of P and N under these different chemical states has great potential to inﬂuence global biogeochemical cycles 14,16 , the longevity of anoxic events 15 and therefore the timing of bioticrecovery after the end-Permian mass extinction. These factors suggest that further evaluation of the global extent of ferruginous conditions is required to fully understand biogeochemical controls on
Interestingly enough, many employers are actually struggling to fill positions despite an unemployment rate that has only marginally dropped in the past year. A recent employment outlook survey showed that 52 percent of U.S. employers are experiencing difficulty filling mission-critical positions within their companies, up from 14 percent in 2010. 2 This challenge will only be exacerbated as more jobs become available.
The expansion of the Ministerial portfolio for Local Government to include a Community Recovery and Resilience function is in recognition of the leading role local government and local communities need to play in building resilience. Resilience starts with how communities view themselves. It is a mindset that recognises these natural disasters are a way of life in Queensland, that local communities need to be smart and practical in their approach to planning ahead of these events, and that they must respond together to rebuild quickly and more effectively each time an event occurs.
but the business cycle aside, the social classes that come off worst in the competition for jobs are, clearly, the poorest. Black unemployment in the United States, for example, is regularly twice that of whites, in good times or bad. Unskilled workers in the secondary labor force have the least job security of any group, and the lowest status. Their work is often casual, menial, highly routine and, always, poorly paid. Alienation from the creative process is greatest, in general, in the working class. Clearly, if any group were to experience constant difficulty in gaining and holding wage work and in deriving self-esteem and gratification from their employment it would be those in the lowest social classes. It comes as no surprise to find that recoveryfrom psychosis is worst in the lower socio-economic groups. Admission rates were higher for pauper lunatics in Victorian Britain and, as we saw in Chapter 5, their recovery rates were lower. Similarly, in modern times, not only is the incidence of serious mental disorder greater in the lower classes (as we saw in Chapter 2), but the outcome from psychosis is distinctly worse. A study conducted in Bristol, England, of males with schizophrenia first admitted in the early 1950s found that patients from the lower social classes had longer hospital stays, were much less likely to be improved or recovered at the time of discharge, were liable to be readmitted earlier and were very much more likely to become chronically institutionalized than were upper- class patients. The lower-class patients in the community, moreover, were less likely to be employed and showed worse overall social adjustment. 51 The author
68 Exact figures on funding for rubble clearance are not available. However, UN Habitat report that the lack of funding from donors for this purpose is a major barrier to supporting returns and resettlement. NGO representatives interviewed by Oxfam said that donors did not regard rubble removal as ‘sexy’.
69 Funding has been made available for NGOs, which have undertaken rubble removal as part of an integrated approach to construction and livelihoods (e.g. through cash-for-work programmes); however, this is too small- scale to have made an impact. ECHO and other donors have said that only a large-scale mechanised approach by private contractors using cranes, diggers, and trucks will have the required impact, given the volume of rubble created by the quake. Large-scale mechanised approaches have started in the formal part of the city, but large projects for rubble management in very dense informal settlements have not yet been initiated.
FEMA has also taken actions to encourage collaboration among state and local officials to share experiences and expertise related to disaster recovery. For example, FEMA’s Long-Term Community Recovery Branch, working through ESF #14, hosted a teleconference linking officials in Florida, Mississippi, Colorado, and Iowa with experience recovering from previous disasters to provide information to officials in Texas recovering from Hurricane Ike. In this way, officials with direct experience in the recovery process were able to share good practices related to recovery planning, disaster funds administration, and coordinating regional efforts with the participants from Texas. According to FEMA officials, this collaboration helped the Texas officials identify recovery projects and develop a community recovery plan. In addition, FEMA is considering ways to further facilitate the sharing of lessons learned for disaster recovery, including creating a peer-to-peer mentoring program where experienced local officials can provide technical assistance, advice, and support to communities impacted by the 2005 Gulf Coast hurricanes. However, these officials told us that this idea is still at an early stage and additional specifics are not yet available.
(Jablonski & Raup 1995), particularly when phylogenetic relationships are taken into account (Friedman 2009; Put- tick et al. 2017a). Other traits relating to extinction risk during mass extinctions include diet and motility (Payne & Clapham 2012; Song et al. 2012), with evidence that ecological specialists and slow dispersers cannot tolerate rapid environmental change (Erwin 1998; Jablonski 2005). Geographical factors such as range size and occu- pied latitude have also been suggested, as these traits may influence survival during spatially heterogeneous distur- bances (Erwin 1998; Powell 2007; Jablonski 2008). How- ever, some authors have suggested that few, if any, traits reduce extinction risk during mass extinctions (Jablonski 2005; Dunhill & Wills 2015). In addition, most of these studies have focused on marine taxa, and extinction selec- tivity in the terrestrial realm in deep time has only recently come under investigation.
This article studies the quasi-stationary behaviour of population processes with unbounded absorption rate, including one-dimensional birth and death processes with catastrophes and multi-dimensional birth and death processes, modeling biological populations in interac- tion. To handle this situation, we develop original non-linear Lyapunov criteria. We obtain the exponential convergence in total variation of the conditional distributions to a unique quasi-stationary distribution, uniformly with respect to the initial distribution. Our results cover all one-dimensional birth and death processes which come down from infinity with catastrophe rate satisfying appropriate bounds, and multi- dimensional birth and death models with stronger intra-specific than inter-specific competition.
The shortcoming of these studies is that they can still only yield conclusions about correlations between extinctionevents large enough to be visible above the noise level in the data. It is perfectly reasonable to adopt the position that the large extinctionevents have exogenous causes, but that there is a certain level of “background” events which are endogenous in ori- gin. In order to address this issue a number of re- searchers have constructed plots of the distribution of the sizes of extinctionevents; non-uniformity in such a distribution might offer support for distinct mass and background extinction mechanisms (Raup 1986, Kauff- man 1993, Sol´ e and Bascompte 1996). One such dis- tribution is shown in Figure 3, which is a histogram of the number of families dying out per stage. This is not strictly the same thing as the sizes of extinctionevents, since several distinct events may contribute to the total in a given stage. However, since most extinc- tion dates are only accurate to the nearest stage it is the best we can do. If many independent extinctionevents were to occur in each stage, then one would ex- pect, from Poisson statistics (see, for instance, Grim- mett and Stirzaker 1992), that the histogram would be approximately normally distributed. In actual fact, as the figure makes clear, the distribution is highly skewed and very far from a normal distribution (Raup 1996). This may indicate that extinction at different times is correlated, with a characteristic correlation time of the same order of magnitude as or larger than the typical stage length so that the extinctions within a
sured in different physical units. The ceilometer data have been averaged to the vertical grid of the MAX-DOAS re- trieval (200 m) prior to the convolution with the averaging kernel. No or only limited overlap between outgoing beam and field of view of the telescope of the ceilometer is present in the lowermost 120 m. For this reason, ceilometer data be- tween surface and 150 m altitude are set to a constant value equal to the signal at 150 m during the convolution process. Therefore the lowermost layer of the convolved ceilometer profiles is subject to large uncertainties when high gradients near the surface exist. It is important to note that ceilome- ter and MAX-DOAS instruments retrieve different quanti- ties. The MAX-DOAS retrieval algorithms yield extinction profiles, whereas the backscatter profiles from the ceilometer cannot be directly converted to an extinction profile without further assumptions on the ratio between backscatter and ex- tinction. This so-called lidar ratio is not known a priori and is a function of the size and optical properties of the particles, which vary with time and altitude. Therefore ceilometer and MAX-DOAS profiles can only be compared qualitatively in terms of the vertical structure of the boundary layer. Further- more, the MAX-DOAS instruments average over a large hor- izontal distance of up to several tens of kilometres, whereas the ceilometer probes the atmosphere directly over the mea- surement site.
Often, these “accounts” include details on the efforts of environmental/conservation groups (such as RAGE) and how these companies are taking it upon themselves to commit funds to anti-poaching initiatives and encourage awareness of rhinoceros conservation and protection. Corporate reporting on the plight of the rhinoceros suggests that “extinction” is no longer limited to the domain of ecologists. The harsh reality of losing one of Africa’s Big Five coincides with a never-before-seen response from leading South African corporations. Accounts of rhinoceros conservation (which is not directly linked to these organisations ’ primary business objectives) imply that corporate discourses are evolving and organisations ’ boundaries are expanding in reaction to the possible loss of this species (see Llewellyn, 1994; Gray et al., 1995). More specifically, “ extinction ” is emerging as a corporate (rather than solely biological/scientific) construct and an important sustainability consideration. Additional disclosure also suggests a desire to demonstrate a broad level of accountability and responsibility. In this way, extinction accounting goes a step beyond the now well-documented “accounting for biodiversity”. The reporting is more than just descriptive, focussed on compliance with specific laws, regulations or codes of best practice (Milne et al., 2009; Jones and Solomon, 2013; Cho et al., 2015) or driven by the need to secure social acceptance (Milne et al., 2009; Tregidga, 2013; Atkins et al., 2016). Companies are recognising their unique ability to affect change by devoting funds and resources to reverse extinction trends.
trees, resulting in negative effects on the growth, devel- opment, and mortality of seedlings (Ellis et al. 2006; Zheng et al. 2013). Therefore, the recovery of carbon and nitrogen metabolism after winter is an important process impacting mangrove survival. Leakage of elec- trolytes through damaged cell membrane is well docu- mented after exposure to freezing temperatures (Burr et al. 1990; Islam et al. 2009), and low-temperature electro- lyte leakage is a good indicator of chilling tolerance dur- ing vegetative growth (Bertin et al. 1996). In the present study, the cold damage index of the 2-year-old K. obo- vata was significantly higher than that of other older (5-, 9-, and 54-year-old) trees, and electrolyte leakage in the 2-year-old trees increased by 42.8 % at T1 compared with that in the same trees at T4 (Fig. 2). The most prominent symptoms of cold injury in the 2-year-old seedlings were leaf scorch and defoliation In contrast to the 2-year-old trees, the 5- and 9-year-old trees were not obviously injured and only few of them had fallen leaves. The oldest trees (54 years old) had very few yellow leaves. These results were in accordance with the changes in electrolyte leakage at T1 (Fig. 2). Thus, the resistance to leaf drop of K. obovata increased with tree ages. However, only leaf electrolyte leakage of the
et al. 2006; Fischer and Lindenmayer 2007). The resulting edge habitat generally benefits common and generalist species at the expense of rare and more vulnerable species (Ries et al. 2004). Opening of formerly remote areas can facilitate poaching of imperiled and sensitive species, serve as a conduit for invasive and non-native species (including pathogens), and provide a gateway to further and more per- manent development (Fahrig 2003). Although habitat loss and fragmentation occur on broad scales and are moder- ately difficult to mitigate, these processes are relatively well studied (WebTable 1) and represent a medium-low research Figure 3. Freshwater biodiversity in relation to the extent of shale gas basins: normalized species richness (a) globally and (b) within the US; US-only (c) amphibian species richness, (d) crayfish species richness, and (e) fish species richness. Biodiversity data (a–d) were derived from Collen et al. (2013); data in (e) were derived from Hoekstra et al. (2010; downloaded from www.databasin.org and used under a Creative Commons Attribution 3.0 License, http://creativecommons. org/licenses/by/3.0). All freshwater biodiversity data are shown in relation to the extent of shale gas basins assessed by the US Energy Information Administration (www.eia.gov) and represent known extents as of May 2011; countries/regions included in the global shale gas assessment are: Mexico, Canada, Colombia, Venezuela, Argentina, Chile, Uruguay, Paraguay, Bolivia, Brazil, Algeria, Tunisia, Libya, South Africa, France, Germany, Netherlands, Norway, Denmark, Sweden, the UK, Poland, Ukraine, Lithuania, Romania, Bulgaria, Hungary, China, India, Pakistan, Turkey, and Australia.
How do you encourage associates to use a wider skills mix? In the past there have been problems with dentists using hygienists. Within the dentist’s contracts a deduction was made from associate contracts to pay for hygienists. We are also trying a model where dentists work 30 min extra each day and then take half a day off, hiring nurses to carry out work for patients during this time.
In addition to humanity’s dependence upon natural systems to provide resources, plants and animals provide opportunities for affiliation or relationships with other forms of life (Ramzy 2015). The ‘biophilia hypothesis’ introduced and popularized by Wilson in the 1980’s, seeks to explain humanity's innate affinity for the natural world (McMahana and Estes, 2015). The ‘biophilia hypothesis’ suggests that the desire of people to live in a world inhabited by other living things originates from the environment in which humans evolved (Wilson 2002). Given that humanity spent several million years in the savannas and transitional woodlands of Africa, before taking up agriculture and moving into urban environments, “a sense of genetic unity, kinship and deep history are among the values that bond us to the living