Species management in aquatic Habitats overview of sub projects and their management

This is the Species management in aquatic Habitats overview of sub projects and their management produced by the Environment Agency in 1998. This report was under the R&D Project, which it was initiated in 1995 to provide information on species of conservation value of particular relevance to the Environment Agency (then the National Rivers Authority, NRA), in relation to its activities affecting aquatic environments. Outputs comprise Species Action Plans (SAPs), practical management guidelines for Agency staff and third parties, and various research and survey outputs to improve the knowledge base on the status and ecological requirements of priority species. This R&D Technical Report provides an overview of the work undertaken, additionally identifying lessons to be learnt in the management of species-related research within the framework of the UK Biodiversity Action Plan. The process of species selection was initially based upon a wide ranging review of priority species of relevance to the then NRA, encompassing both highly threatened species and species that are relatively common but are at particular risk from Agency activities.

Species management in aquatic Habitats WRc Dec 1993

This is the Species management in aquatic Habitats WRc Dec 1993 produced by the National Rivers Authority in 1993. This report is focused on the Phase 1 of the Species Management in Aquatic Habitats, based on the Development of priority lists of rare and nuisance species for the National Rivers Authority (NRA). Certain ‘nuisance’ species cause problems for conservation by having a negative impact on more valued species or ecosystems. This project was initiated as part of a programme of research to develop strategies for the management of both rare and nuisance species. This project identified key rare and nuisance species of interest to the NRA and prioritised research needs to develop conservation strategies for these species. A combined provisional list of almost a thousand rare species, a priority list of 58 species of potential interest and a priority list of nine nuisance species was developed by a process of literature review and from suggestions by NRA conservation staff.

Species management in aquatic Habitats WRc Nov 1993

This is the Species management in aquatic Habitats WRc Nov 1993 produced by the National Rivers Authority (NRA) in 1993. This report identified key rare and nuisance species of interest to the NRA and prioritised research needs to develop conservation strategies for these species. The NRA has in the past adopted a habitat maintenance and protection approach to conservation paying less attention at individual species. There is a risk that conservation based on a habitat management policy will no further the conservation of certain species. In addition, certain ‘nuisance’ species cause problems for conservation by having a negative impact on more valued species or ecosystems. Through the combination of the review of current legislation and literature and consultation with NRA staff, this project identified key rare and nuisance species of interest to the NRA and prioritised research needs to develop conservation strategies for these species.

Species management in aquatic habitats WRc RD Interim 1997

This is the Species management in aquatic Habitats WRc Interim 1997 document produced by the Environment Agency in 1997. This document reports progress on R&D Project 640, which aims to provide information on species of conservation value of particular relevance to the Environment Agency, in relation to its activities affecting aquatic environments. A range of stand-alone outputs is being produced, comprising Species Action Plans, practical management guidelines for Agency staff and third parties, and various research outputs to improve the knowledge base on the status and ecological requirements of priority species. The species of conservation values are: water shrew, daubenton’s bat, Kingfisher, yellow wagtail, Grey wagtail, sand martin, reed bunting, dipper, marsh warbler, great crested new, spined loach, brook lamprey, river lamprey, sea lamprey, shining rams-horn snail, little whirlpool rams-horn snail, depressed river mussel, a freshwater pea mussel, native crayfish, and triangular club-rush. The process of species selection was altered during the course of the project by the report on biodiversity by the UK Biodiversity Steering Group (1995). Whilst still including species that were not particularly endangered but were greatly influenced by the activities of the Agency, the project addressed species on the ‘short’ and ‘middle’ priority lists of the Biodiversity report, particularly those for which the Agency had specific responsibilities.

Incorporating uncertainty in predictive species distribution modelling

Motivated by the need to solve ecological problems (climate change, habitat fragmentation and biological invasions), there has been increasing interest in species distribution models (SDMs). Predictions from these models inform conservation policy, invasive species management and disease-control measures. However, predictions are subject to uncertainty, the degree and source of which is often unrecognized. Here, we review the SDM literature in the context of uncertainty, focusing on three main classes of SDM: niche-based models, demographic models and process-based models. We identify sources of uncertainty for each class and discuss how uncertainty can be minimized or included in the modelling process to give realistic measures of confidence around predictions. Because this has typically not been performed, we conclude that uncertainty in SDMs has often been underestimated and a false precision assigned to predictions of geographical distribution. We identify areas where development of new statistical tools will improve predictions from distribution models, notably the development of hierarchical models that link different types of distribution model and their attendant uncertainties across spatial scales. Finally, we discuss the need to develop more defensible methods for assessing predictive performance, quantifying model goodness-of-fit and for assessing the significance of model covariates.

Existing and emerging high impact invasive species are characterized by higher functional responses than natives

Predicting ecological impacts of invasive species and identifying potentially damaging future invaders are research priorities. Since damage by invaders is characterized by their depletion of resources, comparisons of the ‘functional response’ (FR; resource uptake rate as a function of resource density) of invaders and natives might predict invader impact. We tested this by comparing FRs of the ecologically damaging ‘world's worst’ invasive fish, the largemouth bass (Micropterus salmoides), with a native equivalent, the Cape kurper (Sandelia capensis), and an emerging invader, the sharptooth catfish (Clarias gariepinus), with the native river goby (Glossogobius callidus), in South Africa, a global invasion hotspot. Using tadpoles (Hyperolius marmoratus) as prey, we found that the invaders consumed significantly more than natives. Attack rates at low prey densities within invader/native comparisons reflected similarities in predatory strategies; however, both invasive species displayed significantly higher Type II FRs than the native comparators. This was driven by significantly lower prey handling times by invaders, resulting in significantly higher maximum feeding rates. The higher FRs of these invaders are thus congruent with, and can predict, their impacts on native communities. Comparative FRs may be a rapid and reliable method for predicting ecological impacts of emerging and future invasive species.

Predicting invasive species impacts: a community module functional response approach reveals context dependencies

Summary
-Predatory functional responses play integral roles in predator–prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species.
-Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator–prey interactions and thus the predictive capability of the comparative functional response approach.
-We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses.
-Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator.
-Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator.
-This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies.

Coexistence of congeneric native and invasive species: The case of the green algae Codium spp. in northwestern Spain

We examined the patterns of distribution and abundance, and reproductive traits (presence of gametophytes and size at time of reproduction) in the invasive Codium fragile ssp. fragile and the native C. tomentosum and C. vermilara on intertidal habitats of NW Spain at two dates. All three species coexist in the locations and habitats studied, although abundances were low. We found a greater proportion of C. fragile ssp. fragile towards the east of the Cantabrian coast and on upper levels on the shore, where conditions are more stressful. The proportion of thalli bearing gametangia in C. fragile ssp. fragile was greater than in the native species in all habitats. The presence of gametangia was size-dependent for all species, with the invasive species maturing at a smaller size, which combined with the previous features, might confer competitive advantages to this species over the native species. We also demonstrated that molecular analyses are necessary for the correct identification of C. fragile subspecies.

Scenario of the spread of the invasive species Zaprionus indianus Gupta, 1970 (Diptera, Drosophilidae) in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)