4 World Records of Biomass, Productivity and Species
Diversity
It can be assumed that the highest values of biomass, productivity and diversity
reflect responses of long lasting processes, during evolutionary times, to environmental conditions and pressures close to optimality.
The Eucalyptus regnans forest with a midstory of Acacia and an understory of
tree ferns in temperate SE Australia has been identified as the highest density of
living material in the ecosystems of the world (Pan et al. 2013; Keith et al. 2009).
Field measurements and calculations revealed a maximum carbon density of 1819 tC
ha
À1 in living above-ground biomass and 2844 tC ha
À1 in total biomass (Keith et al.
2009). This world record of biomass is neither combined with highest species
richness nor with highest productivity. However, the relating soils were characterized as “fertile soils with high soil water-holding capacity and nutrient availability
compared with most forest soils in Australia” (Keith et al. 2009: 11639).
The biomass and structure of an ecosystem is mainly determined by abiotic
factors such as climate and soil conditions, and is assumed to be more or less
independent of productivity or species composition (Neuenkamp et al. 2016;
Lohbeck et al. 2015; Guo 2007).
In many cases increasing resource use by vascular plants increases the net
primary productivity. However, this is not always the case (Isbell et al. 2013;
Farrior et al. 2013; James et al. 2005). In general, an increasing uptake of nutrients
accompanies an increase in respiration rate, luxury consumption, decreasing stability, attack of parasites, consumption by herbivores, and competition, for example. As
a result, the net productivity can also decrease. On the other hand, an increase in
species diversity can increase ecosystem productivity, irrespective of nutrient or
water availability (Craven et al. 2016). The magnitude of the net primary productivity mirrors environmental properties such as solar energy, soil fertility, water
supply, and internal cycling of the system. Many ecosystems are characterized by
positive rates of productivity during the growing season and negative rates during
the dormant or drought period, when respiration exceeds the productivity of living
material (cf. Lebrija-Trejos et al. 2010; de Haan and Ferreira 2006; Katz et al. 2005;
Golley 1994; Lindemann 1942).
Net primary productivity is extremely high if not highest in tropical floodplain
swamps of the Amazon with C 4 grasses such as Echinochloa polystachya (up to
9.93 kg m
À2 year
À1 in Morison et al. 2000, or 8.93 kg m
À2 year
À1 in Piedade et al.
1994) and comparable with the productivity of fertilized maize fields in warm
regions (Singh and Yadava 2014; Esser et al. 2000; Ricklefs and Miller 2000).
These communities are relatively species-poor and have low biomass compared
e.g. to other scrub or forest ecosystems. The relationship between high productivity
and low soil fertility of tropical forest has been described as paradoxical. High
productivity rates based on a very efficient recycling of dead matter by fungi,
bacteria and small invertebrates, and nutrient cycling within the biosphere have
been examined in tropical rainforests even on old, eroded and nutrient-poor soils
Resources for Humans, Plants and Animals: Who Is the Ruler of the Driver? And:. . .
87
Diversity
It can be assumed that the highest values of biomass, productivity and diversity
reflect responses of long lasting processes, during evolutionary times, to environmental conditions and pressures close to optimality.
The Eucalyptus regnans forest with a midstory of Acacia and an understory of
tree ferns in temperate SE Australia has been identified as the highest density of
living material in the ecosystems of the world (Pan et al. 2013; Keith et al. 2009).
Field measurements and calculations revealed a maximum carbon density of 1819 tC
ha
À1 in living above-ground biomass and 2844 tC ha
À1 in total biomass (Keith et al.
2009). This world record of biomass is neither combined with highest species
richness nor with highest productivity. However, the relating soils were characterized as “fertile soils with high soil water-holding capacity and nutrient availability
compared with most forest soils in Australia” (Keith et al. 2009: 11639).
The biomass and structure of an ecosystem is mainly determined by abiotic
factors such as climate and soil conditions, and is assumed to be more or less
independent of productivity or species composition (Neuenkamp et al. 2016;
Lohbeck et al. 2015; Guo 2007).
In many cases increasing resource use by vascular plants increases the net
primary productivity. However, this is not always the case (Isbell et al. 2013;
Farrior et al. 2013; James et al. 2005). In general, an increasing uptake of nutrients
accompanies an increase in respiration rate, luxury consumption, decreasing stability, attack of parasites, consumption by herbivores, and competition, for example. As
a result, the net productivity can also decrease. On the other hand, an increase in
species diversity can increase ecosystem productivity, irrespective of nutrient or
water availability (Craven et al. 2016). The magnitude of the net primary productivity mirrors environmental properties such as solar energy, soil fertility, water
supply, and internal cycling of the system. Many ecosystems are characterized by
positive rates of productivity during the growing season and negative rates during
the dormant or drought period, when respiration exceeds the productivity of living
material (cf. Lebrija-Trejos et al. 2010; de Haan and Ferreira 2006; Katz et al. 2005;
Golley 1994; Lindemann 1942).
Net primary productivity is extremely high if not highest in tropical floodplain
swamps of the Amazon with C 4 grasses such as Echinochloa polystachya (up to
9.93 kg m
À2 year
À1 in Morison et al. 2000, or 8.93 kg m
À2 year
À1 in Piedade et al.
1994) and comparable with the productivity of fertilized maize fields in warm
regions (Singh and Yadava 2014; Esser et al. 2000; Ricklefs and Miller 2000).
These communities are relatively species-poor and have low biomass compared
e.g. to other scrub or forest ecosystems. The relationship between high productivity
and low soil fertility of tropical forest has been described as paradoxical. High
productivity rates based on a very efficient recycling of dead matter by fungi,
bacteria and small invertebrates, and nutrient cycling within the biosphere have
been examined in tropical rainforests even on old, eroded and nutrient-poor soils
Resources for Humans, Plants and Animals: Who Is the Ruler of the Driver? And:. . .
87