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Increased atmospheric nitrogen (N) deposition has been held responsible for the large‐scale invasion of graminoids (grasses, sedges and rushes) in a wide range of habitats from forests to upland heaths, causing dramatic changes in plant species composition. Concurrently with an increase in N deposition over the last century, livestock grazing has intensified in many parts of the world following policy reform, leading to large‐scale degradation of natural and seminatural ecosystems. On the basis of a series of experiments conducted in a Scottish montane ecosystem, we discovered that grazing and N deposition do not operate independently, and the interplay between them is leading to the replacement of valuable moss‐dominated habitat by grasses and sedges. Our study indicates that in setting ‘critical loads’ of N, widely used to minimize habitat degradation, it is necessary to account for substantial amplification of N‐deposition effects by grazing.

Application-level web security refers to vulnerabilities inherent in the code of a web-application itself (irrespective of the technologies in which it is implemented or the security of the web-server/back-end database on which it is built). In the last few months application-level vulnerabilities have been exploited with serious consequences: hackers have tricked e-commerce sites into shipping goods for no charge, usernames and passwords have been harvested and confidential information (such as addresses and credit-card numbers) has been leaked.In this paper we investigate new tools and techniques which address the problem of application-level web security. We (i) describe a scalable structuring mechanism facilitating the abstraction of security policies from large webapplications developed in heterogenous multi-platform environments; (ii) present a tool which assists programmers develop secure applications which are resilient to a wide range of common attacks; and (iii) report results and experience arising from our implementation of these techniques.

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