scholarly journals Threatened species richness along a Himalayan elevational gradient: quantifying the influences of human population density, range size, and geometric constraints

BMC Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Prakash Kumar Paudel ◽  
Jan Sipos ◽  
Jedediah F. Brodie
Alpine Botany ◽  
2021 ◽  
Author(s):  
Christian Körner ◽  
Davnah Urbach ◽  
Jens Paulsen

AbstractMountains are rugged structures in the landscape that are difficult to delineate. Given that they host an overproportional fraction of biodiversity of high ecological and conservational value, conventions on what is mountainous and what not are in need. This short communication aims at explaining the differences among various popular mountain definitions. Defining mountainous terrain is key for global assessments of plant species richness in mountains and their likely responses to climatic change, as well as for assessing the human population density in and around mountainous terrain.


2013 ◽  
Vol 159 ◽  
pp. 137-147 ◽  
Author(s):  
Dian Spear ◽  
Llewellyn C. Foxcroft ◽  
Hugo Bezuidenhout ◽  
Melodie A. McGeoch

Web Ecology ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 63-65
Author(s):  
Simone Fattorini ◽  
Giovanni Strona

Abstract. Human population growth is expected to drive several species to local extinction. Yet, an unexpected high biodiversity can be found even in densely populated areas. Although a positive correlation between human density and biodiversity can be explained by the intermediate disturbance hypothesis, an alternative possible explanation may come from the tendency of human settlements to be located in sites whose environmental conditions are particularly favourable also for many other animal species. To investigate this hypothesis, we studied the relationships between human population density and species richness of native tenebrionid beetles in small Italian islands. We used partial regression analysis to assess the individual contribution of island area (to account for the species–area relationship), elevation (used as a proxy of environmental diversity), and human density to species richness. We found that tenebrionid diversity increased with human population density even after controlling for area and elevation. This may suggest that islands that were (and are) more hospitable to humans are also those which can be more favourable for tenebrionids.


2020 ◽  
Vol 94 (6) ◽  
pp. 2331-2341
Author(s):  
Aluane Silva Ferreira ◽  
Carlos A. Peres ◽  
Pavel Dodonov ◽  
Camila Righetto Cassano

AbstractThe future of tropical forest biodiversity will largely depend on human-modified landscapes. We investigated how medium- to large-bodied mammals respond to factors at local (habitat type), intermediate (land use heterogeneity, forest cover and human population density) and large spatial scales (overall forest cover) in agroforestry landscapes. We surveyed mammals using camera traps in traditional cacao agroforests (cabrucas), intensified cacao agroforests, and forest remnants within two large Atlantic Forest landscapes of southern Bahia, Brazil, representing both high and low forest cover. At the local scale, habitat types differed in their potential to harbour mammal species, with forest remnants and cabrucas showing high conservation value, mainly under contexts of high forest cover, whereas intensified cacao agroforests contained less diversified species assemblages in both landscapes. At intermediate scales, species richness increased with increasing forest cover around forest remnants and intensified cacao agroforests, but the opposite was observed in cabrucas. The effects of human population density were ubiquitous but species-dependent. At the largest scale, species richness was higher in the most forested landscape, highlighting the imperative of maintaining forest remnants to retain forest-dwelling mammals in human-dominated landscapes. We claim that mammal conservation strategies require a multi-scale approach and that no single strategy is likely to maximize persistence of all species. Some species can routinely use traditional agroforests, and a large fraction of mammal diversity can be maintained even if high canopy-cover agroforestry dominates the landscape. Nevertheless, forest patches and highly forested landscapes are essential to ensure the persistence of forest-dwelling and game species.


2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Kyle Barrett ◽  
Christina M. Romagosa ◽  
Matthew I. Williams

Urban areas are expanding globally, and the impact of high human population density (HHPD) on bird species richness remains unresolved. Studies primarily focus on species richness along an urban-to-rural gradient; however, some studies have analyzed larger-scale patterns and found results that contrast with those obtained at smaller scales. To move the discussion beyond static species richness patterns, we analyzed the effect of HHPD on bird assemblage dynamics (year-to-year extinction probability, turnover, changes in species richness) across the United States over a 25-year period. We found that bird assemblages in both high and low human population density areas changed significantly over the period of record. Specifically, bird assemblages increased in species richness on average. Assemblage change in areas of HHPD was not significantly different from assemblage change in areas with LHPD. These results suggest that human population density alone does not alter the persistence of avian assemblage patterns.


2020 ◽  
Author(s):  
Mikko Kuussaari ◽  
Marjaana Toivonen ◽  
Janne Heliölä ◽  
Juha Pöyry ◽  
Jorge Mellado ◽  
...  

Abstract Good knowledge on how increasing urbanization affects biodiversity is essential in order to preserve biodiversity in urban green spaces. We examined how urban development affects species richness and total abundance of butterflies as well as the occurrence and abundance of individual species within the Helsinki metropolitan area in Northern Europe. Repeated butterfly counts in 167 separate 1-km-long transects within Helsinki covered the entire urbanization gradient, quantified by human population density and the proportion of built-up area (within a 50-m buffer surrounding each butterfly transect). We found consistently negative effects of both human population density and built-up area on all studied butterfly variables, though butterflies responded markedly more negatively to increasing human population density than to built-up area. Responses in butterfly species richness and total abundance showed higher variability in relation to proportion of built-up area than to human density, especially in areas of high human density. Increasing human density negatively affected both the abundance and the occurrence of 47% of the 19 most abundant species, whereas, for the proportion of built-up area, the corresponding percentages were 32% and 32%, respectively. Species with high habitat specificity and low mobility showed higher sensitivity to urbanization (especially high human population density) than habitat generalists and mobile species that dominated the urban butterfly communities. Our results suggest that human population density provides a better indicator of urbanization effects on butterflies compared to the proportion of built-up area. The generality of this finding should be verified in other contexts and taxonomic groups.


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