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Explore the correlation between species richness and human population density in Nepal Himalayas, analyzing multiple taxonomic groups. Discover the impact of human settlements on biodiversity, elevation gradients, and forest cover.
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Congruence between species richness and human population density: reconciliation or conflict? Ole R VETAAS Unifob – Global, University of Bergen, 5015 Bergen, Norway, M. CHRISTENSEN University of Copenhagen, Forest and Landscape, Denmark
Congruence between species richness and human population density • Human action is often claimed to be the main cause behind habitat loss and biodiversity reduction. CONTRADICTION to (?) • Large parts of the globe have enhanced biodiversity, and at the same time these areas have a high density of people
AREA , ORGANISMS, and RESEARCH QUESTION • The present study analyses species richness along an elevational gradient in Nepal Himalayas • Seven taxonomic groups including: trees, herbaceous plants, ferns, cryptogams, and fungi • WHAT kind of organism has this correspondence, and why?
INDIA TIBET
Cause Effect ? High Biodiversity High human population Obscured Many Biological options for exploitation Human settlements Species rich cultural landscapes Human settlements
Research question 1 Which organism has a correlation between human population density and species richness along the total elevation gradient
high Ice & rock Alpine Meadows and heath Elevation low TROPICAL FOREST Interpolated species richness Elevation Gradient Montane BETULA Coniferous Forest&…… Evergreen OAK-RHODODENDRON-Forest Deciduous Warm temperate-subtropical Forest 1000 m a.s.l.
INTERPOLATION : ASSUMING ALL SPECIES ARE PRESNET IN ALL 100M INTERVALS BETWEEN LOWER AND UPPER ELEVATION LIMIT This gives total number of species in all different elevation bands from 100 m to 6000 m a.s.l.
Research question 1 Which organism has a correlation between human population density and species richness along the total elevation gradient
Scale and patterns • This large scale pattern may in part be ascribed to the fact that very few people live in very unproductive species-poor areas, such as deserts, sub-arctic-biomes, or high mountains. • The correspondence between species richness and human density may not be evident at shorter spatial extents such as along an human populated elevation gradient.
Elevation and Human population density: focus 200 - 3100 outlier
Research Question 2:Which organism has correlation between richness and human population along the populated part of the gradient 200 - 3100 m a.s.l.
r= ns r= 0.81 r= 0.025 r= -0.55 r= -0.62 r= -0.62 r= -0.70 r= -0.58
Cause effect High biodiversity High human population AREA of elevation zones Species area relationships
Area result outliers
Correlations between log (species richness) and log (area) in km 2 for target taxa between 200-3100 m a.s.l.
Cause Effect High human population High biodiversity Climate Temperature
Forest and people • Forest cover is influenced by human density • Forest cover may influence species richness
humna densuty forest density in % M a.s.l.
Cause Effect High human population High biodiversity reduced forest cover Related to Intermediate disturbance hypothesis
conclusion • Forest cover predicts tree specie richness • Forest cover is determined by climate at higher elevation and human density at lower elevation • Thus people may have a positive impact on tree diversity • Management implication: a moderate reduction of total forest cover may enhance richness rather than reduce it
Thank you for your attention Lopped oak forest rich in species
Exploit the dominant species • This may be done by: • Selective logging in a forest • Lopping or pollarding of canopy trees • Browsing by large mammals
Biodiversity and disturbance species richness Increasing disturbance
Theory Intermediate disturbance hypothesis • Hutchnison (1951), Grime (1973b), and Connell (1978), has suggested that there is higher chance for many species to coexist, when a community or landscape is moderately disturbed. • This tenet is well accepted, although disturbance is difficult to define and measure
Disturbance definition • Many different definitions • Grime: disturbance = reduced or destructed biomass • Browsing, Grazing, Fire or other biomass outtake are regarded as disturbance
Biodiversity; biomass and disturbance species richness increasing biomass increasing disturbance