Low impact of chytridiomycosis on frog recruitment enables persistence in refuges despite high adult mortality

The global chytridiomycosis pandemic caused by the pathogen Batrachochytrium dendrobatidis (. Bd) is implicated in the apparent extinction or severe decline of over 200 amphibian species. Many declined species now only persist in isolated remnant populations. In this study we examine how remnant populations coexist with Bd, focusing on disease impact on adult survival and recruitment potential in the chytridiomycosis-threatened frog Litoria verreauxii alpina. Using skeletochronology we found that the adult male population in both 2011 and 2012 was dominated by a two year old age cohort. The lack of recruitment into the three year old cohort in 2012 indicates that annual adult survival is very low. Combined with high Bd prevalence and heavy infection burdens, the pathogen appears to drive almost complete mortality of breeding adults over their first breeding season. However, adults successfully mate prior to large increases in disease prevalence that occurs during the breeding season. Infection prevalence among tadpoles and juveniles is low. Exposure to warm water could provide a mechanism for avoiding or clearing Bd infection. Relatively low Bd prevalence in juveniles prior to dispersal into terrestrial habitat indicates that Bd has minimal impact on early life history stages. As such, recruitment is probably high, allowing populations to persist despite low adult survival. This dependence on reliable annual recruitment may explain why remnant populations persist in permanent ponds rather than ephemeral ponds that were historically occupied. New management strategies that focus on increasing recruitment may provide a way forward for the management of disease-threatened amphibian species.

Interventions for reducing extinction risk in chytridiomycosis-threatened amphibians

Wildlife diseases pose an increasing threat to biodiversity and are a major management challenge. A striking example of this threat is the emergence of chytridiomycosis. Despite diagnosis of chytridiomycosis as an important driver of global amphibian declines 15 years ago, researchers have yet to devise effective large-scale management responses other than biosecurity measures to mitigate disease spread and the establishment of disease-free captive assurance colonies prior to or during disease outbreaks. We examined the development of management actions that can be implemented after an epidemic in surviving populations. We developed a conceptual framework with clear interventions to guide experimental management and applied research so that further extinctions of amphibian species threatened by chytridiomycosis might be prevented. Within our framework, there are 2 management approaches: reducing Batrachochytrium dendrobatidis (the fungus that causes chytridiomycosis) in the environment or on amphibians and increasing the capacity of populations to persist despite increased mortality from disease. The latter approach emphasizes that mitigation does not necessarily need to focus on reducing disease-associated mortality. We propose promising management actions that can be implemented and tested based on current knowledge and that include habitat manipulation, antifungal treatments, animal translocation, bioaugmentation, head starting, and selection for resistance. Case studies where these strategies are being implemented will demonstrate their potential to save critically endangered species.

Decline and re-expansion of an amphibian with high prevalence of chytrid fungus

The disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is a key driver of global amphibian declines. While chytridiomycosis can cause extinction, many susceptible species persist after an initial period of decline, albeit with reduced abundance and distribution. Emerging evidence indicates that amphibian abundance can recover within remnant populations, but to date, the capacity of amphibian populations to re-expand into historically occupied habitat has received limited research attention. We surveyed 145 sites in 2011 and 2012 to determine if populations of the whistling tree frog (Litoria verreauxii verreauxii) have re-expanded compared with historical data from 1975-1976, 1990 and 1996. L. v. verreauxii underwent a major range contraction likely caused by chytridiomycosis between the first two time periods. Populations have recently re-expanded, with 39 new sites colonised despite high prevalence of Bd. We suspect that changes in disease dynamics have resulted in the increased coexistence of L. v. verreauxii and Bd. Habitat attributes at sites that retained frogs for the duration of the study indicate that high quality habitat may contribute to buffering against population level effects of Bd. Colonised sites had more coarse woody debris, suggesting a possible habitat management strategy to encourage range expansion for this species. Given sufficient time and adequate source populations in high quality habitat, it is possible that other amphibian species may re-expand from chytridiomycosis-induced declines. This provides an impetus for the protection of historical, but currently unoccupied amphibian habitats and highlights the importance of maintaining high quality habitat to help species survive novel shocks such as pandemic diseases.

Reservoir-host amplification of disease impact in an endangered amphibian

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd, with some species tolerating infection, while others experience rapid mortality. Reservoir hosts - species that carry infection while maintaining high abundance, but are rarely killed by disease - can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We combine a laboratory study with field surveys, disease sampling, and statistical modeling to investigate the role of reservoir hosts in chytridiomycosis dynamics and species decline in an amphibian community in south-eastern Australia. We show that the non-declining common eastern froglet (Crinia signifera) is a reservoir host for Bd, with laboratory animals carrying intense infection burdens over 12 weeks and the majority of wild sampled individuals carrying intense infections. We find that the presence of C. signifera is strongly associated with Bd prevalence in the sympatric, IUCN red-listed northern corroboree frog (Pseudophryne pengilleyi). Consistent with disease amplification by a reservoir host, we find that P. pengilleyi has declined from areas with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines can continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined amphibian species. Reintroductions and in situ management strategies must focus on identifying reservoir hosts and minimizing exposure of threatened species.

Urban amphibian assemblages as metacommunities

1. Urban ecosystems are expanding throughout the world, and urban ecology is attracting increasing research interest. Some authors have questioned the value of existing ecological theories for understanding the processes and consequences of urbanization.
2. In order to assess the applicability of metacommunity theory to urban systems, I evaluated three assumptions that underlie the theory – the effect of patch area, the effect of patch isolation, and species–environment relations – using data on assemblages of pond-breeding amphibians in the Greater Melbourne area of Australia. I also assessed the relative impact of habitat fragmentation, habitat isolation, and changes to habitat quality on these assemblages.
3. Poisson regression modelling provided support for an important increase in species richness with patch area (pond size) and a decrease in species richness with increasing patch isolation, as measured by surrounding road cover. Holding all other variables constant, species richness was predicted to be 2·8–5·5 times higher at the largest pond than at the smallest, while the most isolated pond was predicted to have 12–19% of the species richness of the least isolated pond. Thus, the data were consistent with the first two assumptions of metacommunity theory evaluated.
4. The quality of habitat at a pond was also important, with a predicted 44–56% decrease in the number of species detected at ponds with a surrounding vertical wall compared with those with a gently sloping bank. This demonstrates that environmental differences between habitat patches were also influencing amphibian assemblages, providing support for the species-sorting and/or mass-effect perspectives of metacommunity theory.
5. Without management intervention, urbanization may lead to a reduction in the number of amphibian species persisting in urban ponds, particularly where increasing isolation of ponds by roads and associated infrastructure reduces the probability of re-colonization following local extinction.

A perspective on the role of natriuretic peptides in amphibian osmoregulation

The natriuretic peptide (NP) system is a complex family of peptides and receptors that is primarily linked to the maintenance of osmotic and cardiovascular homeostasis. In amphibians, the potential role(s) of NPs is complicated by the range of osmoregulatory strategies found in amphibians, and the different tissues that participate in osmoregulation. Atrial NP, brain NP, and C-type NP have been isolated or cloned from a number of species, which has enabled physiological studies to be performed with homologous peptides. In addition, three types of NP receptors have been cloned and partially characterised. Natriuretic peptides are always potent vasodilators in amphibian blood vessels, and ANP has been shown to increase the permeability of the microcirculation. In the perfused kidney, ANP causes vasodilation, diuresis and natriuresis that are caused by an increased GFR rather than effects in the renal tubules. These data are supported by the presence of ANP receptors only on the glomeruli and renal blood vessels. In the bladder and skin, the function of NPs is enigmatic because physiological analysis of the effects of ANP on bladder and skin function has yielded conflicting data with no clear role for NPs being revealed. Overall, NPs often have no direct effect, but in some studies they have been shown to inhibit the function of AVT. In addition, there is evidence that ANP can inhibit salt retention in amphibians since it can inhibit the ability of adrenocorticotrophic hormone or angiotensin II to stimulate corticosteroid secretion. It is proposed that an important role for cardiac NPs could be in the control of hypervolaemia during periods of rapid rehydration, which occurs in terrestrial amphibians.

Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required.

Objectives: To investigate the immediate (12 weeks) and long term (12 months) efficacy of two eccentric exercise programmes for the treatment of patellar tendinopathy.

Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months.

Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups.

Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain.

Organisational decline and renewal in an Australian voluntary association

Voluntary associations are an integral fonn of social capital in democratic societies. These associations make vital contributions to community life. Many associations are successful in meeting the needs of their constituency and thrive over many decades. These long serving associations are not static vehicles, like all organisations, they are subject to internal and external pressures for change. It is a significant challenge for volunteer associations to maintain 'a watch' on the external environment whilst responding to the needs of their stakeholders. Previously vibrant associations may experience a decline in membership and social standing as a result of significant changes in society and technology. We track a nonprofit voluntary association from its inception in the 1960s through it responses to major environmental turbulence during the late 1980s, 1990s, and early 2000s when the survival of
the organisation was in doubt. We outline the changes that took place from 2003 that reorientated, revitalised and reshaped the association including a major shift in focus from services to members to services to the community. This study provides academics and practitioners with an appreciation of the forces of organisational decline and a case study of successful change in a voluntary association.

The rise and decline of the New South Wales cooperative housing societies

In the past, New South Wales cooperative housing societies made an important contribution to the financing of housing construction. In this paper the expansion and later contraction of the societies is explained. It is shown that, in recent times, not only have they suffered from a drying up of loan funding, but also a great number have operated at far below their possible level of efficiency.

A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy

Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy.

Methods: Two different eccentric exercise regimens were used by subjects with a long duration of pain with activity (more than six months). (a) Nine consecutive patients (10 tendons; eight men, one woman; mean age 22 years) performed eccentric exercise with the ankle joint in a standard (foot flat) position. (b) Eight patients (12 tendons; five men, three women; mean age 28 years) performed eccentric training standing on a 25° decline board, designed to increase load on the knee extensor mechanism. The eccentric training was performed twice daily, with three sets of 15 repetitions, for 12 weeks. Primary outcome measures were (a) 100 mm visual analogue scale (VAS), where the subject recorded the amount of pain during activity, and (b) return to previous activity. Follow up was at 12 weeks, with a further limited follow up at 15 months.

Results: Good clinical results were obtained in the group who trained on the decline board, with six patients (nine tendons) returning to sport and showing a significantly reduced amount of pain over the 12 week period. Mean VAS scores fell from 74.2 to 28.5 (p = 0.004). At 15 months, four patients (five tendons) reported satisfactory results (mean VAS 26.2). In the standard squat group the results were poor, with only one athlete returning to previous activity. Mean VAS scores in this group were 79.0 at baseline and 72.3 at 12 weeks (p = 0.144).

Conclusion: In a small group of patients with patellar tendinopathy, eccentric squats on a decline board produced encouraging results in terms of pain reduction and return to function in the short term. Eccentric exercise using standard single leg squats in a similar sized group appeared to be a less effective form of rehabilitation in reducing pain and returning subjects to previous levels of activity.

Regional faunal decline – reptile occurrence in fragmented rural landscapes of south-eastern Australia

Many species of reptiles are sedentary and depend on ground-layer habitats, suggesting that they may be particularly vulnerable to landscape changes that result in isolation or degradation of native vegetation. We investigated patterns of reptile distribution and abundance in remnant woodland across the Victorian Riverina, south-eastern Australia, a bioregion highly modified (>90%) by clearing for agriculture. Reptiles were intensively surveyed by pitfall trapping and censuses at 60 sites, stratified to sample small (<30 ha) and large (>30 ha) remnants, and linear strips of roadside and streamside vegetation, across the regional environmental gradient. The recorded assemblage of 21 species was characterised by low abundance and patchy distribution of species. Reptiles were not recorded by either survey technique at 22% of sites and at a further 10% only a single individual was detected. More than half (53%) of all records were of two widespread, generalist skink species. Multivariate models showed that the distribution of reptiles is influenced by factors operating at several levels. The environmental gradient exerts a strong influence, with increasing species richness and numbers of individuals from east (moister, higher elevation) to west (drier, lower elevation). Differences existed between types of remnants, with roadside vegetation standing out as important; this probably reflects greater structural heterogeneity of ground and shrub strata than in remnants subject to grazing by stock. Although comparative historical data are lacking, we argue that there has been a region-wide decline in the status of reptiles in the Victorian Riverina involving: (1) overall population decline commensurate with loss of >90% of native vegetation; (2) disproportionate decline of grassy dry woodlands and their fauna (cf. floodplains); and (3) changes to populations and assemblages in surviving remnants due to effects of land-use on reptile habitats. Many species now occur as disjunct populations, vulnerable to changing land-use. The status of reptiles in rural Australia warrants greater attention than has been given to date. Effective conservation of this component of the biota requires better understanding of the population dynamics, habitat use and dispersal capacity of species; and a commitment to landscape restoration coupled with effective ecological monitoring.

The rise and decline of Libya as a rogue state

From 1980 until 2006, the Great Socialist People’s Libyan Arab Jamahiriya (Libya) was considered by the United States as a “Rogue State”. However, in May 2006, the U.S. Secretary of State, Condoleezza Rice, welcomed Libya back into the world community and declared that this erstwhile enemy had reformed. But has the American public registered this change in Libya’s status? Has this return to the fold influenced U.S. public opinion about Libya and its eccentric leader, Colonel Qaddafi? Or is it merely a case of new foes pushing old ones out of mind? What might some of America’s new “Rogue State” enemies learn from Libya’s example? This paper explores the nexus between the tumultuous U.S.-Libyan relationship and the U.S. public, and analyses how and why perceptions of Libya have changed.

Decline in physical fitness from childhood to adulthood associated with increased obesity and insulin resistance in adults

To examine how fitness in both childhood and adulthood is associated with adult obesity and insulin resistance. A prospective cohort study set in Australia in 2004-2006 followed up a cohort of 647 adults who had participated in the Australian Schools Health and Fitness Survey in 1985 and who had undergone anthropometry and cardiorespiratory fitness assessment during the survey. Outcome measures were insulin resistance and obesity, defined as a homeostasis model assessment index above the 75th sex-specific percentile and BMI ≥30 kg/m^sup 2^, respectively. Lower levels of child cardiorespiratory fitness were associated with increased odds of adult obesity (adjusted odds ratio [OR] per unit decrease 3.0 [95% CI 1.6- 5.6]) and insulin resistance (1.7 [1.1-2.6]). A decline in fitness level between childhood and adulthood was associated with increased obesity (4.5 [2.6-7.7]) and insulin resistance (2.1 [1.5- 2.9]) per unit decline. A decline in fitness from childhood to adulthood, and by inference a decline in physical activity, is associated with obesity and insulin resistance in adulthood. Programs aimed at maintaining high childhood physical activity levels into adulthood may have potential for reducing the burden of obesity and type 2 diabetes in adults.