Impact of Soil Nematodes on Salt-marsh Plants: a Pilot Experiment
Keywords:Artemisia maritima, fenamiphos, Festuca rubra, nematicide, plant competition, salt marsh.
AbstractWe tested whether the removal of nematodes by means of nematicide application changed plant performance or influenced plant competition. The study involved the two common plant species Artemisia maritima and Festuca rubra growing in intact sods collected from a temperate salt marsh. Half of the sods were treated with fenamiphos ('Nemacure', Bayer AG), a nematicide controlling both endo- and ectoparasitic nematodes. In untreated soil, the number of both total and plant-parasitic nematodes (7000 vs. 1000 per 100g fresh soil, respectively) was comparable to accounts from other salt marsh systems. After four months, the nematicide had reduced nematode numbers by 90%, but no influence on plant biomass or competitive ability of the two plant species was observed. As we did not follow the trajectory of nematicide effects on the nematodes, the exposure period of the test plants to low numbers of nematodes cannot be assessed. Experimental periods may need to be extended in order to evaluate long-term effects of reduced nematode numbers on plant productivity and plant competition in temperate salt marshes. On the basis of this pilot experiment we regard plant-parasitic nematodes to have a minor direct impact on productivity and interspecific relationship between the salt-marsh plant species investigated.