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Floodplain wetlands provide an important subsidy for riverine food webs as sites of high algal production. However, this subsidy depends on the degree of landscape connectivity during flood pulses, which provides the opportunity for movement of higher order consumers between rivers and floodplains to access these productive habitats. Changes in floodplain inundation extent and duration, due to variable wet season flows or water resource development (WRD), can impact landscape connectivity and ultimately the magnitude of the food web subsidy.We explored landscape connectivity using graph theory and derived four new metrics to measure how different flow scenarios can affect connectivity and algal production. We considered a historic scenario with the present level of water resource development in our study area, the Mitchell River, and a WRD scenario with the inclusion of three new dams in the catchment. We generated 240 unique daily spatial graphs, using surface water inundation maps across 40‐day flood events to compare a dry year (2006), an average flow year (2001) and a wet year (2009) with and without a WRD scenario.Drier years and WRD scenario resulted in floodplain fragmentation, potentially constraining the movement of higher order consumers. Changes in connectivity due to WRD resulted in predicted reductions of up to 26% of algal production on the floodplain that was otherwise connected to the main river channels.Synthesis and applications. The approach developed in this study provides new metrics to identify how changes in floodplain surface water extent due to water resource development and climatic variation may impact ecosystem function such as connectivity that facilitates access of higher order consumers to primary production in floodplain wetlands. With a direct link to river flow alteration, these metrics can inform catchment planning and management to ensure that the conservation of floodplain ecosystem functions is adequately considered in water resource management decisions. [ABSTRACT FROM AUTHOR]

Connectivity is regarded globally as a guiding principle for conservation planning, but due to difficulties in quantifying connectivity, empirical data remain scarce. Lack of meaningful connectivity metrics is likely leading to inadequate representation of important biological connections in reserve networks. Identifying patterns in landscape connectivity can, theoretically, improve the design of conservation areas., We used a network model to estimate seascape connectivity for coral reef-associated fishes in a subtropical bay in Australia. The model accounted for two scales of connectivity: (i) within mosaics at a local scale and (ii) among these mosaics at a regional scale. Connections among mosaics were modelled using estimations of post-larval small and intermediate movement distances represented by home ranges of two fish species., Modelled connectivity patterns were assessed with existing data on fish diversity. For fishes with intermediate home ranges (0-6 km), connectivity [quantified by the index Probability of Connectivity ( dPC)] explained 51-60% of species diversity. At smaller home ranges (0-1 km), species diversity was associated closely with intramosaic connectivity quantified by the index dPCintra., Mosaics and their region-wide connections were ranked for their contribution to overall seascape connectivity and compared against current positions and boundaries of reserves. Our matching shows that only three of the 10 most important mosaics are at least partly encompassed within a reserve, and only a single important regional connection lies within a reserve., Synthesis and applications. Notwithstanding its formal recognition in reserve planning, connectivity is rarely accounted for in practice, mainly because suitable metrics of connectivity are not available in planning phases. Here, we show how a network analysis can be effectively used in conservation planning by identifying biological connectivity inside and outside present reserve networks. Our results demonstrate clearly that connectivity is insufficiently represented within a reserve network. We also provide evidence of key pathways in need of protection to avoid nullifying the benefits of protecting key reefs. The guiding principle of protecting connections among habitats can be achieved more effectively in future, by formally incorporating our findings into the decision framework. [ABSTRACT FROM AUTHOR]

Preventing the arrival of invasive species is the most effective way of controlling their impact. Preventative strategies may be 'offensive' aimed at preventing the invader leaving colonised locations or 'defensive' aimed at preventing its arrival at uninvaded locations. The limited resources for invasive species control must be prioritized, particularly for numerous vulnerable locations or uncertainty about which sites are already invaded., We developed an integrative modelling framework to prioritise locations for either strategy by incorporating connectivity and habitat suitability. We applied this framework to a data set comprising 5189 water bodies in Wisconsin and Michigan, U.S.A, for zebra mussels Dreissena polymorpha and Eurasian watermilfoil Myriophyllum spicatum. We developed the framework with a spatial graph based on recreational boater movement and habitat suitability models., An historical graph comprised 3105 natural lakes connected in one of 18 components, whereas a total of 3944 water bodies (lakes and reservoirs) were connected in one of 13 separate components in a graph of the contemporary system. Habitat suitability models accounted for around half of the deviance in the distribution data for each species., There was a distinct spatial pattern in the levels of risk and subsequent recommended allocation of management interventions across several levels of investment. Higher risk water bodies were generally found in the largest component of the spatial graph. At comparatively low levels of investment, where managers target 5% of all locales to control D. polymorpha, the results suggested that 71% and 27% of this effort should be committed to defensive and offensive strategies, respectively, in the largest component. For M. spicatum, 92% and 8% of this effort should be allocated in this component to defensive and offensive strategies, respectively. It is only with much greater investment that water bodies in other components should be targeted., Synthesis and applications. Allocating limited resources to prevent the spread of invasive species is a challenge that transcends ecosystems and geography. We successfully identified a reduced number of locations to target for offensive and defensive intervention strategies for two species. This framework is readily applicable to other aquatic and terrestrial ecosystems vulnerable to invasive species. [ABSTRACT FROM AUTHOR]