The Invasion Ecology of Common Wall Lizard (Podarcis Muralis): Population Dynamics, Interactions and Adaptations

The potentially damaging outcomes of species introductions to areas outside of their natural range are well known, and invasive non-native species are regarded as one of the most significant threats to biodiversity worldwide. Social perceptions of non-native species are open to subjective influence, and in a rapidly changing world the implications of species introductions are becoming less defined. Understanding the ecology of invasions and the human perceptions of them, is therefore fundamentally important for managing all stages of species introductions, relying on a multidisciplinary approach to understanding the invasion process. Invasions can also provide opportunities to study adaptive responses of organisms to novel or changing environments, which in turn can provide insight into mechanistic workings of the invasion process and range expansion. In this study I investigate the ecology of introduced populations of the Common Wall lizard (Podarcis muralis). Using a multidisciplinary approach including population ecology, functional ecology, predictive modelling, social science, and behavioural experiments, I focus on the species’ invasion potential, adaptive responses, and implications for ecological impacts on native lizards in the UK and on Vancouver Island, British Columbia. I found that morphological differences between populations were associated with ancestral origins and infer a greater invasion potential for animals of Italian origin over French. Comparison of physical and performance traits, and a broad dietary niche of P. muralis, indicate considerable overlap between P. muralis and native lizards, suggesting high potential for competitive interaction. However, the varied behavioural responses observed towards scent cues in P. muralis and native lizards suggests an interplay between naivety and threat sensitivity may influence interspecific interaction. Models of predicted range expansion suggest P. muralis populations are likely to remain localised, but that potential for secondary translocation is likely to increase with increasing population size, particularly in urban habitats. I also found clear indication that charismatic non-native species such as P. muralis, may have use as model species with which to raise awareness and minimise the subjectivity shaping perceptions of invasive species in general

ICT–supported reforms of service delivery in Flemish cities: testing the concept of 'information ecology'

This paper explores organizational reforms in Flemish cities related to making the cities’ individual service delivery more efficient, customer orientated, customer friendly and integrated. The paper is the first one of a recently started research project and PhD research about the complexity of managing ICT-supported change of ‘individual’ service delivery. The overall objective of this paper is to set the stage for the research project’s research design in terms of its theoretical framework. Therefore, we report about our first explorative, inductive and descriptive findings related to this type of change within one city. We firstly inductively report about the objectives and the objects of change. Secondly, we develop a provisional theoretical framework. We therefore take the notion of an information ecology as a conceptual starting point and use a combination of elements of neo-institutional theory, system theory and a political perspective on organizational development. In order to explore the potentialities of this approach, we test the framework’s value for understanding the changes within the city. The framework enabled us to describe and analyze this type of reforms without neglecting the complexity of these changes. It tries to link some important public administration theories to the study of the e-government phenomenon that is still an important challenge. The most important lesson is that further refinement of the conceptual framework is needed. Although the analysis shows that the framework offers a conceptual basis to analyze front and back office reforms within public organizations, it still lacks a full and straightforward operationalization of its components, constructs, relations, etc

An Experimental Test of Buffer Utility as a Technique for Managing Pool-Breeding Amphibians

Vegetated buffers are used extensively to manage wetland-dependent wildlife. Despite widespread application, buffer utility has not been experimentally validated for most species. To address this gap, we conducted a six-year, landscape-scale experiment, testing how buffers of different widths affect the demographic structure of two amphibian species at 11 ephemeral pools in a working forest of the northeastern U.S. We randomly assigned each pool to one of three treatments (i.e., reference, 100m buffer, 30m buffer) and clearcut to create buffers. We captured all spotted salamanders and wood frogs breeding in each pool and examined the impacts of treatment and hydroperiod on breeding-population abundance, sex ratio, and recapture rate. The negative effects of clearcutting tended to increase as forest-buffer width decreased and be strongest for salamanders and when other stressors were present (e.g., at short-hydroperiod pools). Recapture rates were reduced in the 30m, but not 100m, treatment. Throughout the experiment for frogs, and during the first year post-cut for salamanders, the predicted mean proportion of recaptured adults in the 30m treatment was only 62% and 40%, respectively, of that in the reference treatment. Frog sex ratio and abundance did not differ across treatments, but salamander sex ratios were increasingly male-biased in both cut treatments. By the final year, there were on average, only about 40% and 65% as many females predicted in the 100m and 30m treatments, respectively, compared to the first year. Breeding salamanders at short-hydroperiod pools were about 10% as abundant in the 100m versus reference treatment. Our study demonstrates that buffers partially mitigate the impacts of habitat disturbance on wetland-dependent amphibians, but buffer width and hydroperiod critically mediate that process. We provide the first experimental evidence showing that 30-m-wide buffers may be insufficient for maintaining resilient breeding populations of pool-dependent amphibians, at least during the first six years post-disturbance

Resilience trinity: safeguarding ecosystem functioning and services across three different time horizons and decision contexts

Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi‐faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time‐horizons: 1) reactive, when there is an imminent threat to ES resilience and a high pressure to act, 2) adjustive, when the threat is known in general but there is still time to adapt management and 3) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology and engineering are often implicitly focussing on provident, adjustive or reactive resilience, respectively, but these different notions of resilience and their corresponding social, ecological and economic tradeoffs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer‐term management actions are not missed while urgent threats to ES are given priority

Ecological theory as a foundation to control pathogenic invasion in aquaculture

Detrimental host-pathogen interactions are a normal phenomenon in aquaculture animal production, and have been counteracted by prophylactic use of antibiotics. Especially, the youngest life stages of cultivated aquatic animals are susceptible to pathogen invasion, resulting in disease and mortality. To establish a more sustainable aquatic food production, there is a need for new microbial management strategies that focus on 'join them' and not the traditional 'beat them' approaches. We argue that ecological theory could serve as a foundation for developing sustainable microbial management methods that prevent pathogenic disease in larviculture. Management of the water microbiota in aquaculture systems according to ecological selection principles has been shown to decrease opportunistic pathogen pressure and to result in an improved performance of the cultured animals. We hypothesize that manipulation of the biodiversity of the gut microbiota can increase the host's resistance against pathogenic invasion and infection. However, substantial barriers need to be overcome before active management of the intestinal microbiota can effectively be applied in larviculture

A State of the Art of Governance Literature on adaptation to climate change. Towards a research agenda

This report provides a state-of-the-art overview of governance literature on adaptation strategies. What has recent research taught us on adaptation from the perspective of governance and to what research agenda does this lead? This report is structured as followed. Firstly, it will be argued why adaptation is a matter of governance. Secondly, the research methods for the literature study will be outlined. Thirdly, the results of the literature study will portray the findings in terms of the themes and foci with, respectively, environmental studies, spatial planning and development studies, and public administration studies. Finally, a comparative analysis of these findings will lead to a research agenda for future research on governance of adaptatio

Supporting Water Governance and Climate Change Adaptation Through Systemic Praxis

Understanding and working with multiple perspectives on issues of change is an essential part of managing “common pool” water resources. In uncertain and complex situations arising from changes in human settlements and climate, both lives and livelihoods can be at stake. One individual’s or group’s choices can adversely affect others and traditional processes of participation and legislation are often inadequate. Discourse on environmental law recognises that noncompliance with legislation is associated with weak national governance structures. A systemic approach to managing change is required to appreciate interconnections among issues at various levels and to mediate different stakeholdings. Yet there are no blueprints for effecting systemic transformations of complex situations. This paper explores how the implementation of climate change adaptation can be supported when grounded in situations, such as water governance. It draws on the authors’ experiences of systemic praxis in the water sector