131 resultados para Lizard-island
Resumo:
This publication takes the form of a written version of my inaugural lecture, which was presented at Queen’s University Belfast on 10 March 2010. It is more personal and considerably more self-indulgent than would normally be acceptable in an article, with more of my own experiences and also my own references than would usually be considered proper. However, the bestowal of such a title as Professor of Island Geography is something of a marker of the maturity not just of myself but maybe also for island studies. After a section describing my path into island geography, the lecture deals with the negativities of islands and the seeming futility of studying them only then to identify a new or at least enhanced regard for islands as places with which to interact and to examine. Reference is made to islands throughout the world, but with some focus on the small islands off Ireland. The development of island studies as a discipline is then briefly described before the lecture concludes with reference to its title quotation on St Helena by considering that place’s islandness and how this affected/affects it in both the 17th and 21st centuries.
Resumo:
Using data from field introduction experiments with Gammarus spp. conducted in the rivers of a small island, commencing in 1949, with resampling in the 60s, 70s, 80s, 90s and finally in 2005, we aimed to examine the long-term interaction of the native freshwater amphipod Gammarus duebeni celticus with the introduced G. pulex. Using physico-chemical data from a 2005 island-wide survey, we also aimed to find what environmental factors could influence the distribution of the two species.
Resumo:
The common lizard (Zootoca vivipara) is Ireland’s only native reptile, forming a key part of the island’s biodiversity. However, there is a general paucity of distributional and abundance data for the species. In this study, we collated incidental records for common lizard sightings to define the distribution of the species in Northern Ireland. Maximum entropy modelling was employed to describe species-habitat associations. The resulting predicted landscape favourability was used to evaluate the current status of the species based on the distribution of its maximum potential range in relation to the degree of fragmentation of remaining suitable habitat. In common with previous studies in the Republic of Ireland, sightings were highly clustered indicating under-recording, observer bias, and fragmentation of suitable habitat. A total of 98 records were collated from 1905 to 2009. The species was recorded in 63 (ca. 34%) of 186 × 10 km Northern Irish grid squares. Lizard occurrence was strongly and positively associated with landscapes dominated by heathland, bog and coastal habitats. The single best approximating model correctly classified the presence of lizards in 84.2% of cases. Upland heath, lowland raised bog and sand dune systems are all subject to Habitat Action Plans in Northern Ireland and are threatened by conversion to agriculture, afforestation, invasive species encroachment and infrastructural development. Consequently, remaining common lizard populations are likely to be small, isolated and highly fragmented. Establishment of an ecological network to preserve connectivity of remaining heath and bog will not only benefit remaining common lizard populations but biodiversity in general.