Biomedical subjects

Peter Convey

Publications and source records attributed to Peter Convey.

5 recordsLinked to original sources

PubMed2005

Environmental constraints on life histories in Antarctic ecosystems: tempos, timings and predictability.

Knowledge of Antarctic biotas and environments has increased dramatically in recent years. There has also been a rapid increase in the use of novel technologies. Despite this, some fundamental aspects of environmental control that structure physiological, ecological and life-history traits in Antarctic organisms have received little attention. Possibly the most important of these is the timing and availability of resources, and the way in which this dictates the tempo or pace of life. The clearest view of this effect comes from comparisons of species living in different habitats. Here, we (i) show that the timing and extent of resource availability, from nutrients to colonisable space, differ across Antarctic marine, intertidal and terrestrial habitats, and (ii) illustrate that these differences affect the rate at which organisms function. Consequently, there are many dramatic biological differences between organisms that live as little as 10 m apart, but have gaping voids between them ecologically. Identifying the effects of environmental timing and predictability requires detailed analysis in a wide context, where Antarctic terrestrial and marine ecosystems are at one extreme of the continuum of available environments for many characteristics including temperature, ice cover and seasonality. Anthropocentrically, Antarctica is harsh and as might be expected terrestrial animal and plant diversity and biomass are restricted. By contrast, Antarctic marine biotas are rich and diverse, and several phyla are represented at levels greater than global averages. There has been much debate on the relative importance of various physical factors that structure the characteristics of Antarctic biotas. This is especially so for temperature and seasonality, and their effects on physiology, life history and biodiversity. More recently, habitat age and persistence through previous ice maxima have been identified as key factors dictating biodiversity and endemism. Modern molecular methods have also recently been incorporated into many traditional areas of polar biology. Environmental predictability dictates many of the biological characters seen in all of these areas of Antarctic research.

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PubMed2005

Biological invasions in the Antarctic: extent, impacts and implications.

Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of species-poor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels.

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PubMed2004

Latitudinal variation in habitat specificity of ameronothrid mites (Oribatida).

Ameronothroid mites, including Ameronothridae, Fortuyniidae and Selenoribatidae, are unique among the Oribatida through having a global distribution from the tropics to the poles, and occupying a diversity of habitats including terrestrial, marine and freshwater. Their ecological diversification is of considerable interest from both the perspective of evolution over geological timescales, and the detail of the underlying processes. Given their widespread global distribution, it seems likely that historical global events (tectonic and climatic) have played a fundamental role in their ecological diversification. Previous studies of sub-Antarctic island arthropods have generated considerable circumstantial evidence in support of glaciation being a primary factor influencing ecological patterns: lower habitat specificity and weaker interspecific interactions are associated with more recent (postglacial) vegetated terrestrial biotopes, as compared to the older epilithic and littoral biotopes (which are assumed to have been present, albeit reduced in extent, during Neogene glacial maxima). Here, we use ameronothrid mites as a case study to examine the extent to which the above island scenario generalizes globally across latitudes affected by glaciation. We show that, unlike congeners or even conspecifics at lower latitudes in each hemisphere which are restricted to marine environments, the species found at higher latitudes (especially Alaskozetes antarcticus, Ameronothrus dubinini, Ameronothrus lineatus, and Halozetes belgicae) show greater affinity for terrestrial environments. They show a transition or expansion of habitat use (from marine-influenced to terrestrial habitats) implicit with a lower degree of habitat specificity, in relation to increasing latitude. We contend that the terrestrial environment at higher latitudes in both hemispheres has been colonized by these ameronothrid mite species following the various glaciation events, facilitated by a lack of competition experienced in their low diversity communities, in a manner which represents a larger scale demonstration of the processes described on sub-Antarctic islands.

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PubMed2004

Molecular analysis of geographic patterns of eukaryotic diversity in Antarctic soils.

We describe the application of molecular biological techniques to estimate eukaryotic diversity (primarily fungi, algae, and protists) in Antarctic soils across a latitudinal and environmental gradient between approximately 60 and 87 degrees S. The data were used to (i) test the hypothesis that diversity would decrease with increasing southerly latitude and environmental severity, as is generally claimed for "higher" faunal and plant groups, and (ii) investigate the level of endemicity displayed in different taxonomic groups. Only limited support was obtained for a systematic decrease in diversity with latitude, and then only at the level of a gross comparison between maritime (Antarctic Peninsula/Scotia Arc) and continental Antarctic sites. While the most southerly continental Antarctic site was three to four times less diverse than all maritime sites, there was no evidence for a trend of decreasing diversity across the entire range of the maritime Antarctic (60 to 72 degrees S). Rather, we found the reverse pattern, with highest diversity at sites on Alexander Island (ca. 72 degrees S), at the southern limit of the maritime Antarctic. The very limited overlap found between the eukaryotic biota of the different study sites, combined with their generally low relatedness to existing sequence databases, indicates a high level of Antarctic site isolation and possibly endemicity, a pattern not consistent with similar studies on other continents.

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PubMed2002

Ecological responses to recent climate change.

There is now ample evidence of the ecological impacts of recent climate change, from polar terrestrial to tropical marine environments. The responses of both flora and fauna span an array of ecosystems and organizational hierarchies, from the species to the community levels. Despite continued uncertainty as to community and ecosystem trajectories under global change, our review exposes a coherent pattern of ecological change across systems. Although we are only at an early stage in the projected trends of global warming, ecological responses to recent climate change are already clearly visible.

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