Self-penetration by the mycoparasiteDimargaris Cristalligena

Summary Ultrastructural evidence is presented for self-penetration by hyphae of the mycoparasiteDimargaris cristalligena. Plasmalemmal invagination occurs in a manner similar to that observed during penetration of a conventional host, and is accompanied by the synthesis of a penetration jacket. During self-penetration, however, there is little collar formation and the invading hypha fails to differentiate into a haustorial body.     

Fertilization acid production in Psammechinus eggs under pH clamp conditions, and the effects of some pyrazine derivatives

The production of fertilisation acid in eggs of Psammechinus miliaris, fertilised with sperm, was studied under pH clamp conditions. The more usual procedure, in which acid production is recorded as a fall in pH of the external medium, can give reliable information about acid release, but the method is cumbersome compared with pH clamping. Inhibition of acid production by two pyrazines (amiloride and benzamil) was studied, as it has been reported that amiloride blocks acid formation in some species. No change in acid production was seen, although generation was slowed by amiloride. It is concluded that sodium-proton exchange following fertilisation does not occur through amiloride-sensitive channels.     

Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems

The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict ‘unexpected’ risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems.     

Challenges facing the introduction of SMART patrols in a game reserve,western Tanzania

The spatial monitoring and reporting tool (SMART) is being implemented in Tanzania's protected areas to help improve the efficiency of ranger patrols. Unfortunately, there has been no attempt to understand users' perspectives regarding site‐specific factors likely to affect its use. In this study, we investigated the perspectives of staff in Ugalla Game Reserve, a protected area in western Tanzania, to understand the challenges that affect the use of SMART in the reserve. The main challenges included a lack of motivation to use SMART, limited knowledge of SMART among game scouts, insufficient ranger capacity, difficulty collecting data during night patrols, limited resources for patrolling, and difficulty accessing some remote sections of Ugalla. The presence of trophy hunting company patrol teams has led Ugalla rangers to concentrate their effort in less‐patrolled areas. We recommend introducing incentives to encourage game rangers to use SMART alongside improving patrol coverage in wet seasons. Advanced and regular refresher trainings in SMART should be conducted to enhance data collection. Furthermore, game scouts should be trained and equipped to participate effectively in the SMART process. Although SMART is now becoming increasingly popular in Tanzania, understanding local factors that influence its implementation will be important to improve uptake.     

Friends of mine: An invasive freshwater mussel facilitates growth of invasive macrophytes and mediates their competitive interactions

1. Increasing rates of invasions in ecosystems worldwide necessitate experiments to determine the role of biotic interactions in the success and impact of multiple alien species. Here, we examined competitive and facilitative interactions among various combinations of three widespread and often co-occurring invaders: the zebra mussel Dreissena polymorpha, and the macrophytes Elodea canadensis and Elodea nuttallii.
2. Using a mesocosm-based, factorial experimental design, we assessed the effect of interspecific competition on macrophyte growth rates in the absence and presence at varying biomass of D. polymorpha.
3. Growth rates (wet g/day) of E. canadensis and E. nuttallii were similar when grown in isolation. When grown together, in the absence of D. polymorpha, E. canadensis growth was not significantly reduced in the presence of E. nuttallii and vice versa. In the presence of D. polymorpha (26.0 ± 1 mm), monocultural growth of E. canadensis was largely unaffected, while E. nuttallii growth was strongly enhanced. Low (2.64 g) and medium (3.96 g) mussel biomass led to negative interspecific effects between E. canadensis and E. nuttallii; at high (5.28 g) mussel biomass, the effect of interspecific competition was negated.
4. Overall, D. polymorpha alleviated competitive interactions between the two invasive macrophytes when all three species co-occurred, and substantially enhanced growth of E. nuttallii with increasing mussel biomass, thereby suggesting a possible influence on the relative dominance of these macrophytes in the field.
5. Our study demonstrates how facilitations can cause shifts in dominance among closely related invaders. The consequences of such facilitations for the structure and function of communities remain to be explored generally.