Introduction
Benefits of grassland phytodiversity for livestock production
Diversity and productivity
Management | Country | Plant diversity | Production | Further ecosystem services | References |
---|---|---|---|---|---|
Rotational grazing (dairy cows), no fertiliser, clipping of excessive ungrazed forage | Pennsylvania, USA | 2–9 sown species | 0 (herbage intake, milk production) | + (higher conjugated linoleic acid content of milk with more species) | Soder et al. (2006) |
Rotational grazing (beef cattle) | Illinois, USA | 3–8 sown species | 0 (stocking rate, average daily gain, despite initially higher herbage mass in more diverse plots before grazing) | n.d. | Tracy and Faulkner (2006) |
Rotational grazing (to different target heights), mowing | Pennsylvania, USA | 1–7 sown species | 0 (in favourable years higher yields in fertilised monocultures) | + (more consistent yields in diverging weather conditions, improved CP and IVTDMD at first harvest, more stable quality of complex mixtures over season) | Deak et al. (2009) |
Montane semi-natural grassland (78 plots under agricultural management, grazed or cut) | Germany | 8–33 species; average of 20 species | 0 (for species richness as well as effective diversity and Camargo’s evenness) plant community composition explained productivity | n.d. | Kahmen et al. (2005) |
Park grass experiment, different fertilisation treatments since 1856 with N, P or K, two cuts (initially one cut followed by grazing) | England | 3–44 species per 200 m² | − (less species numbers with more production) | + (stability of hay biomass was positively correlated with species number, albeit weakly) | Silvertown et al. (2006) |
Experimental restoration sites (sown on arable land, no weeding), late cut with autumn and winter sheep-grazing | England | Mixtures with 6–17 or 25–41 species (species-poor and -rich, respectively) | + (linear relationship between difference in species number among treatments and increase in hay yield) | 0 (no effect on fodder quality) | Bullock et al. (2001) |
Experimental plots, no weeding, one cut/year, followed over 9 years | The Netherlands | 0–15 sown species, on average 10 to 14 species in total | + (productivity increased with number of sown species) However, if total species number was considered, there was no clear relationship | + (stability increased with sown species number, but not with total species number) | Bezemer and van der Putten (2007) |
Experimental plots, rotational or continuous grazing, initial weeding during establishment | New Zealand | 0–8 functional groups | + (for sown species in spring) 0 (for total species production in spring as well as total and sown species production in autumn) | + (resistance to invasion, resilience to disturbance) | Dodd et al. (2004) |
Indoor cafeteria experiment with sheep | China | 1–11 species | + (more voluntary average daily intake of sheep with higher diversity) | n.d. | Wang et al. (2010) |
854 steppe sites, hay fields or grazed | Inner Mongolia, China | Observational study, up to 36 species per m² | + (at all scales; at regional scale, this correlated with annual rainfall and soil nitrogen; grazing did not affect form of relationship) | n.d. | Bai et al. (2007) |
Experimental plots (cut) as well as survey on 37 pastures | Pennsylvania, USA | 1–15 sown species in experimental plots; up to 11 species in surveys | + (often more production in more diverse pastures) | + (less weed invasion) | Tracy and Sanderson (2004) |
Experimental plots as well as preexisting vegetation invaded by exotic species at four locations, one cut/year | North Dakota, USA | 2–32 sown species | Mostly + (in experimental plots) 0 (in preexisting vegetation) Changing relationships over time and sites | n.d. | Guo et al. (2006) |
Experimental plots, cutting (1–4 times/year), fertilisation (0–200 kg N ha−1 a−1), regular weeding | Germany | 1–16 sown species | + (plant production) | n.d. | Weigelt et al. (2009) |
Experimental plots, cut twice/year, regular weeding | Germany | 1–60 sown species | n.d. | + (increased carbon storage in soil) | Steinbeiss et al. (2008) |
Experimental plots, regular weeding | Portugal | 1–14 sown species | + (plant biomass) | + (water use) | Caldeira et al. (2001) |
Gradient from forest edge to abandoned pasture | Québec, Canada | Observational study, up to 16 species per 0.75 m² | Different relationships determined by limiting resources affecting productivity; if pooled together: humped relation; however, this may confound determining environmental variables | n.d. | De Lafontaine and Houle (2007) |
Microcosm experiment, four harvests from December to May | New Zealand | 1–9 sown species | n.d. | + (less potential nitrification and nitrous oxide production with more species, especially with legumes in mixture), 0 (no effect on methane uptake) | Niklaus et al. (2006) |
Microcosm experiment with heat/drought stress | Belgium | 1–8 sown species | + (more plant biomass with more species before drought stress) | + (better water acquisition with more species),-(less survival of plants in mixtures) | Van Peer et al. (2004) |
Meta-analysis of data from 171 studies | n.a. | No range given; local scale (<20 km) | Mostly humped, followed by 0, −, + | n.d. | Mittelbach et al. (2001) |
Meta-analysis of data from 1339 plots in 12 natural grassland systems | USA (nine systems), Tanzania, India, Finland | 0–59 species | − (nonlinear structural equation modelling indicated competitive effects, but no positive effect of species richness on production) | n.d. | Grace et al. (2007) |
Meta-analysis of data from 163 studies | n.a. | No range given | Mainly unimodal in temperate zone Mainly + in tropics in total: 60: 0, 46: +, 37 humped, 20: − | n.d. | Pärtel et al. (2007) |
Diversity and other services for livestock production
Livestock management to enhance grassland phytodiversity
Selective grazing
Spatial dimension | Description | Unit involved | Temporal dimension |
---|---|---|---|
Bite | Area of a bite | Individual (head) | 1–2 s |
Feeding station | Total of bites of a standing grazer (circular arc of the head) | Individual | 5–100 s |
Grazing patch | Cluster of feeding stations of the same intake rate | Few individuals | 1–30 min |
Feeding site | Collection of grazing patches during a grazing interval | Sub-herd | 1–4 h |
Pasture, habitat/camp | Pasture–in the open landscape related to a central resting and watering place | Herd | 1–4 weeks |
Habitat/home range | All habitats in an open landscape | Population | 1–12 months |