Matthew Grainger

Is Succession-based Management of Coastal Dune Forest Restoration Valid?

Habitat restoration and the theory of ecological succession are linked intrinsically. However, restoration management does not always rely on successional principles. This separation between theory and practical application may stem from the failure of succession to achieve restoration targets. Here we test the predictions of succession in a restoration context to ascertain the validity of succession-based management. Specifically we answer the following 4 questions: 1) does the rate of species turnover decrease as coastal dune forest develops; 2) is there a sequence of changing species “types” from pioneer species adapted to harsh conditions to species adapted to high levels of competition; 3) is this sequence of types directional and the same across all sites with similar climatic conditions; and 4) does species diversity increase or decrease? Our study took place in 7 coastal dune forest sites of various ages regenerating after mining disturbance. We conducted tree surveys in 1999, 2001, 2005, and 2009 and herbaceous plant surveys in 1995, 1999, 2003, and 2005. We assessed trends in species turnover, composition, diversity, richness, and evenness to see if these were congruent with successional theories. Patterns in turnover for both taxa showed a decelerating decrease. Sites of a similar age shared similar species composition of coastal dune forest trees and herbaceous plants. As sites aged, they increased in the number and diversity of species. Succession-based management is a valid approach to dune forest rehabilitation as long as restoration managers recognize disturbance as an ecological reality.

Model selection and averaging in the assessment of the drivers of household food waste to reduce the probability of false positives

Food waste from households contributes the greatest proportion to total food waste in developed countries. Therefore, food waste reduction requires an understanding of the socio-economic (contextual and behavioural) factors that lead to its generation within the household. Addressing such a complex subject calls for sound methodological approaches that until now have been conditioned by the large number of factors involved in waste generation, by the lack of a recognised definition, and by limited available data. This work contributes to food waste generation literature by using one of the largest available datasets that includes data on the objective amount of avoidable household food waste, along with information on a series of socio-economic factors. In order to address one aspect of the complexity of the problem, machine learning algorithms (random forests and boruta) for variable selection integrated with linear modelling, model selection and averaging are implemented. Model selection addresses model structural uncertainty, which is not routinely considered in assessments of food waste in literature. The main drivers of food waste in the home selected in the most parsimonious models include household size, the presence of fussy eaters, employment status, home ownership status, and the local authority. Results, regardless of which variable set the models are run on, point toward large households as being a key target element for food waste reduction interventions.

Using the Value of Information to improve conservation decision making: Value of Information for conservation decisions

Conservation decisions are challenging, not only because they often involve difficult conflicts among outcomes that people value, but because our understanding of the natural world and our effects on it is fraught with uncertainty. Value of Information (VoI) methods provide an approach for understanding and managing uncertainty from the standpoint of the decision maker. These methods are commonly used in other fields (e.g. economics, public health) and are increasingly used in biodiversity conservation. This decision‐analytical approach can identify the best management alternative to select where the effectiveness of interventions is uncertain, and can help to decide when to act and when to delay action until after further research. We review the use of VoI in the environmental domain, reflect on the need for greater uptake of VoI, particularly for strategic conservation planning, and suggest promising areas for new research. We also suggest common reporting standards as a means of increasing the leverage of this powerful tool.

Informing decisions on an extremely data poor species facing imminent extinction

Some of the species that are believed to have the highest probability of extinction are also amongst the most poorly known, and this makes it extremely difficult to decide how to spend scarce resources. Assessments of conservation status made on the basis of loss or degradation of habitat and lack of records may provide compelling indications of a decline in geographical range and population size, but they do not help identify where conservation action might be best targeted. Methods for assessing the probability of extinction and for modelling species’ distributions exist, but their data requirements often exceed the information that is available for some of the most urgent conservation cases. Here we use all available information (localities, expert information, climate and landcover) about a high-priority Vietnamese bird species (Edwardss pheasant Lophura edwardsi ) to assess objectively the probability of its persistence, and where surveys or other conservation action should be targeted. It is clear that the species is on the threshold of extinction and there is an urgent need to survey Bach Ma National Park (including the extension) and to consider surveying Ke Go Nature Reserve. This approach has potential to help identify where conservation action should be targeted for other Critically Endangered species for which there is an extreme scarcity of information.

Can Non-Native Species Explain Patterns of Convergence and Deviation in Regenerating Coastal Dune Forest?

The successful restoration of disturbed habitat is influenced by many factors; not least is the introduction of non-native species into the regional species pool. Such species may preclude native colonization and deflect regeneration trajectories away from restoration targets. Successful restoration (commonly measured against reference sites) may therefore be an unobtainable goal. We aimed to identify whether non-native species divert regenerating trajectories of coastal dune forest. Using measures of ecological distance we first determined if successional trajectories of the herbaceous plant community in regenerating coastal dune forest sites were convergent. We then determined if multiple regenerating coastal dune forest sites became more similar to an undisturbed reference site as they aged and which species (both natives and non-natives) contributed the most to dissimilarity between the reference site and regenerating sites. The species composition in regenerating coastal dune forest plots became increasingly convergent as the time since disturbance increased. However, species composition appeared to deviate from that within an undisturbed reference site. Contrary to our expectations, non-native species did not contribute the most to dissimilarity, and thus not to the recorded deviation. The deviation from the reference forest is attributable to the higher abundance of 1) a native forest specialist in the reference site, and 2) the higher abundances of native species adapted to open canopy in the regenerating sites. This deviation of the species composition in regenerating sites from that in the undisturbed reference site may therefore be indicative of successional changes and is not attributable to the presence of non-native species.