Hemiptera community and species responses to grassland sward islets

Sward islet is a term that has been used to describe a patch of longer vegetation in a pasture produced by a reduction in cattle grazing around their dung. They are known to affect the abundance and distribution of grassland arthropods. Hemiptera, like other groups, are found in higher densities within islets than the surrounding sward. Does this modify the community composition or is there just a density effect? Evidence from a paired (islets, non-islets) study at an Irish cattle-grazed site, would suggest that although a change in the density of species explains much of the patterns observed, some species respond to islets in different ways. Grassland Auchenorrhyncha were dominated by two genera, Javesella (mostly J. obscurella and to a lesser extent J. pellucida) and Macrosteles (mostly M. viridigriseus with some M. laevis and M. sexnotatus). The nymphs and to a lesser extent the adults, showed contrasting distribution patterns in relation to islets. Javesella were more common in the islets, whereas Macrosteles showed little difference between the two sub-habitats. Possible reasons for the difference in sub-habitat choice between these two Auchenorrhyncha taxa are discussed

Species' responses along environmental gradients on different spatial scales

The abundance of species on Earth varies greatly - while some occur all over the globe, others can only exist in very distinct regions. Trying to explain the reasoning behind the temporal and spatial variation in the commonness and rarity of species has a long history in ecology and yet, many pieces are still missing to complete the puzzle. This thesis investigates species' responses to changing environmental gradients and asks in how far niche characteristics can be used to predict species' range sizes at different spatial scales. We worked with herbaceous species from semi-natural grasslands as well as deciduous forests, focusing especially on their reactions to abiotic conditions (soil pH, nutrients and light). We could show that the breadth of resources used by species (especially regarding soil pH), as well as their tolerance limits, are reliable predictors for their rarity and commonness across different spatial scales. Furthermore, we believe that niche properties can provide guidelines for conservation decisions, especially concerning the selection of suitable habitats for the reintroduction of species. This is a particularly important task to preserve the worldâ s biodiversity in todayâ s ever changing environments

A trait-based approach for predicting species responses to environmental change from sparse data : how well might terrestrial mammals track climate change?

Acknowledgements LS was supported by two STSMs by the COST Action ES1101 ”Harmonising Global Biodiversity Modelling“ (Harmbio), supported by COST (European Cooperation in Science and Technology). JMB and SMW were funded by CEH projects NEC05264 and NEC05100. JMJT and SCFP are grateful for the support of the Natural Environment Research Council UK (NE/J008001/1). LS, JAH and JMJT conceived the original idea. LS, JAH, JMB, TC & JMJT designed the study; LS collected the data; LS and TC performed the statistical analyses; LS conducted the integrodifference modelling assisted by JMB and SMW. LS conducted the individual-based modelling assisted by SCFP. LS led the writing supported by JMJT, JMB, SCFP, SMW, TC, JAH and GB.Peer reviewedPublisher PD

Effects of rarity form on species' responses to land use

Anthropogenic land-use change causes substantial changes in local and global biodiversity. Rare and common species can differ in sensitivity to land-use change, with rare species expected to be more negatively affected. Rarity may be defined in terms of geographic range size, population density or breadth of habitat requirements. How these three forms of rarity interact in determining global responses to land use is yet to be assessed. Using global data representing 912 vertebrate species, we test for differences in the responses to land use of species characterised by different types of rarity. Species considered rare with respect to all three forms of rarity showed particularly strong declines in disturbed land uses (more than 40% of species and 30% of individuals in the most disturbed land uses). In contrast, species common both geographically and numerically, and with broad habitat requirements, showed strong increases (up to 90% increase in species and 40% in abundance in some land uses). Our results suggest that efforts to understand the vulnerability of species to environmental changes should account for different types of rarity where possible. Our results also have potentially important implications for ecosystem functioning, given that rare species may play unique roles within ecosystems. Article impact statement: Rare species show stronger negative responses to anthropogenic land use than common species

The role of biological interactions in modifying the effects of climate change on intertidal assemblages

The geographic distribution of most species is expected to alter as a consequence of global climate change. Predictions for the extent of these range shifts are frequently based on anticipated changes in temperature using a 'climate envelope' approach, which oversimplifies predictions because it does not consider interactions with other physical and biological factors. The aim of this thesis was to investigate how biological interactions modulate species responses to climate change. On many rocky shores in the NE Atlantic the interaction between limpets, barnacles and canopy forming macroalgae have an important role in structuring rocky shore communities. In particular, limpets control the abundance of macroalgae on the shore through their grazing activities. Through descriptive studies and manipulative experiments the behaviour of a northern/boreal species of limpet, Patella vulgata and a southern/lusitanian species of limpet, P. depressa were compared in relation to canopy forming algae (Fucus patches). As a result of differences in the spatial distribution, behaviour and grazing activity of these two species, if as predicted, there are changes in their relative abundance it is likely there will be implications for rocky shore community dynamics. The second part of my thesis investigated intra- and interspecific competition between two coexisting barnacle taxa with northern and southern centres of distribution. It is predicted that Increased warming will result in a reduction in the abundance of Semibalanus balanoides either as a direct result of increased temperatures or due to an increase in the number of poor spawning years. My results suggest that as a consequence of the gregarious nature of settling S. balanoides cyprids, recruitment success may be reduced irrespective of the numbers of cyprids in the plankton. This will result in more space becoming available for the competing and later settling Chthamalus spp, resulting in a change in barnacle population structure. The likely impacts of population changes and species range shifts in response to increased warming are discussed, with particular emphasis on how the interaction between limpets, barnacles and Fucus may alter. The implications of altered species interactions are then discussed in terms of the effects on community dynamics and ecosystem functioning. Finally the role of biotic interactions in modulating species responses to climate change are discussed with reference to the use of the 'climate envelope' approach in making predictions of species range shifts

Responses of Marine Organisms to Climate Change across Oceans

Climate change is driving changes in the physical and chemical properties of the ocean that have consequences for marine ecosystems. Here, we review evidence for the responses of marine life to recent climate change across ocean regions, from tropical seas to polar oceans. We consider observed changes in calcification rates, demography, abundance, distribution, and phenology of marine species. We draw on a database of observed climate change impacts on marine species, supplemented with evidence in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We discuss factors that limit or facilitate species’ responses, such as fishing pressure, the availability of prey, habitat, light and other resources, and dispersal by ocean currents. We find that general trends in species’ responses are consistent with expectations from climate change, including shifts in distribution to higher latitudes and to deeper locations, advances in spring phenology, declines in calcification, and increases in the abundance of warm-water species. The volume and type of evidence associated with species responses to climate change is variable across ocean regions and taxonomic groups, with predominance of evidence derived from the heavily-studied north Atlantic Ocean. Most investigations of the impact of climate change being associated with the impacts of changing temperature, with few observations of effects of changing oxygen, wave climate, precipitation (coastal waters), or ocean acidification. Observations of species responses that have been linked to anthropogenic climate change are widespread, but are still lacking for some taxonomic groups (e.g., phytoplankton, benthic invertebrates, marine mammals)

Evolutionary genomics can improve prediction of species' responses to climate change

Global climate change (GCC) increasingly threatens biodiversity through the loss of species, and the transformation of entire ecosystems. Many species are challenged by the pace of GCC because they might not be able to respond fast enough to changing biotic and abiotic conditions. Species can respond either by shifting their range, or by persisting in their local habitat. If populations persist, they can tolerate climatic changes through phenotypic plasticity, or genetically adapt to changing conditions depending on their genetic variability and census population size to allow for de novo mutations. Otherwise, populations will experience demographic collapses and species may go extinct. Current approaches to predicting species responses to GCC begin to combine ecological and evolutionary information for species distribution modelling. Including an evolutionary dimension will substantially improve species distribution projections which have not accounted for key processes such as dispersal, adaptive genetic change, demography, or species interactions. However, eco-evolutionary models require new data and methods for the estimation of a species' adaptive potential, which have so far only been available for a small number of model species. To represent global biodiversity, we need to devise large-scale data collection strategies to define the ecology and evolutionary potential of a broad range of species, especially of keystone species of ecosystems. We also need standardized and replicable modelling approaches that integrate these new data to account for eco-evolutionary processes when predicting the impact of GCC on species' survival. Here, we discuss different genomic approaches that can be used to investigate and predict species responses to GCC. This can serve as guidance for researchers looking for the appropriate experimental setup for their particular system. We furthermore highlight future directions for moving forward in the field and allocating available resources more effectively, to implement mitigation measures before species go extinct and ecosystems lose important functions