Effects of haying and agricultural practices on a declining species: The North American wood turtle, Glyptemys insculpta

2007 ◽  
Vol 135 (4) ◽  
pp. 565-575 ◽  
Author(s):  
Raymond A. Saumure ◽  
Thomas B. Herman ◽  
Rodger D. Titman
2008 ◽  
Vol 4 (5) ◽  
pp. 595-598 ◽  
Author(s):  
William B Monahan ◽  
Robert J Hijmans

Our ability to accurately forecast species' geographical responses to climate change requires knowledge of the proximate and ultimate drivers of their distribution. Here, we consider the ecophysiological and demographic determinants of the distribution of a partial migrant, the North American field sparrow, Spizella pusilla . From 1940 to 1963, the field sparrow extended its winter northern range margin 222 km polewards. Such expansion was coincident with not only a geographical expansion into suitable breeding habitats, but also a decrease in mean abundance across sites occupied during the winter surveys. Combined, these trends suggest that declining populations along the expansion front either stopped migrating or altered their autumn migration. The poleward expansion was not coincident with climatically induced decreases in peak metabolic energy demand, but it did track increases in ecosystem net primary productivity. After 1963, the species' lower lethal temperature prevented further poleward movement. These findings show how different ecophysiological constraints can interact to change migration and distribution in a demographically declining species.


2018 ◽  
Author(s):  
Victor Cazalis ◽  
Soumaya Belghali ◽  
Ana S.L. Rodrigues

AbstractProtected areas currently cover about 15% of the global land area, and constitute one of the main tools in biodiversity conservation. Quantifying their effectiveness at protecting species from local decline or extinction involves comparing protected with counterfactual unprotected sites representing “what would have happened to protected sites had they not been protected”. Most studies are based on pairwise comparisons, using neighbour sites to protected areas as counterfactuals, but this choice is often subjective and may be prone to biases. An alternative is to use large-scale biodiversity monitoring datasets, whereby the effect of protected areas is analysed statistically by controlling for landscape differences between protected and unprotected sites, allowing a more targeted and clearly defined measure of the protected areas effect. Here we use the North American Breeding Bird Survey dataset as a case study to investigate the effectiveness of protected areas at conserving bird assemblages. We analysed the effect of protected areas on species richness, on assemblage-level abundance, and on the abundance of individual species by modelling how these metrics relate to the proportion of each site that is protected, while controlling for local habitat, altitude, productivity and for spatial autocorrelation. At the assemblage level, we found almost no relationship between protection and species richness or overall abundance. At the species level, we found that forest species are present in significantly higher abundances within protected forest sites, compared with unprotected forests, with the opposite effect for species that favour open habitats. Hence, even though protected forest assemblages are not richer than those of unprotected forests, they are more typical of this habitat. We also found some evidence that species that avoid human activities tend to be favoured by protection, but found no such effect for regionally declining species. Our results highlight the complexity of assessing protected areas effectiveness, and the necessity of clearly defining the metrics of effectiveness and the controls used in such assessments.


2005 ◽  
Vol 83 (6) ◽  
pp. 765-772 ◽  
Author(s):  
Nathalie Tessier ◽  
Sébastien Rioux Paquette ◽  
François-Joseph Lapointe

Throughout its range, the long-term persistence of the wood turtle (Glyptemys insculpta Le Conte, 1830) is jeopardized by habitat perturbations and commercial collection. The main objective of this study was to acquire knowledge on the genetic structure of wood turtle populations within Quebec, where the species reaches the northernmost limit of its range, to identify proper conservation units. The six known populations in Quebec were genetically characterized using five microsatellite loci. Genetic analyses revealed high variability among all populations (HO ranging from 0.561 to 0.886), suggesting that past population declines have not yet affected their genetic diversity. Since populations are located on both shores of the St. Lawrence River, two colonization hypotheses were tested to determine whether the River acted as a dispersal route or as a barrier. Results of AMOVA tests, phylogenetic analyses, and assignment tests demonstrated the clear distinction between populations from both shores, and three genetically different units were identified: the two populations on the north shore and a single homogenous group on the south shore.


2006 ◽  
Vol 175 (4S) ◽  
pp. 511-512
Author(s):  
David G. McLeod ◽  
Ira Klimberg ◽  
Donald Gleason ◽  
Gerald Chodak ◽  
Thomas Morris ◽  
...  

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