Invertebrate herbivory on floating-leaf macrophytes at the northeast of Argentina: should the damage be taken into account in estimations of plant biomass?

Fedra S Martínez,Celeste Franceschini

doi:10.1590/0001-3765201820170415

Abstract

We assessed the damage produced by invertebrate herbivores per leaf lamina and per m2 of populations floating-leaf macrophytes of Neotropical wetlands in the growth and decay periods, and assessed if the damage produced by the herbivores should be taken into account in the estimations of plant biomass of these macrophytes or not. The biomass removed per lamina and per m2 was higher during the growth period than in decay period in Nymphoides indica and Hydrocleys nymphoides, while Nymphaea prolifera had low values of herbivory in growth period. During decay period this plant is only present as vegetative propagules. According to the values of biomass removed per m2 of N. indica, underestimation up to 17.69% should be produced in cases that herbivory do not should be taking account to evaluate these plant parameters on this macrophyte. Therefore, for the study of biomass and productivity in the study area, we suggest the use of corrected lamina biomass after estimating the biomass removed by herbivores on N. indica. The values of damage in N. indica emphasize the importance of this macrophyte as a food resource for invertebrate herbivores in the trophic networks of the Neotropical wetlands.

Highlights

Recent studies from wetlands in the Northern Hemisphere, mainly in temperate regions show that the herbivory in freshwater macrophytes is significant and can reduce the plant biomass (Bakker et al 2016) and plant abundance (Wood et al 2017) by 44-48%
H. nymphoides offered to the herbivores significantly more leaf biomass in the growth period (H= 32. 06, p< 0.0001) than in the decay period, while N. indica showed no significant differences between these periods (H= 3.2, p= 0.0734)
The great damage produced by herbivores in H. nymphoides and N. indica in the growth period could be related to the highest availability of resources per leaf and per m2 in these macrophytes (Coley et al 1985)

Summary

Introduction

Recent studies from wetlands in the Northern Hemisphere, mainly in temperate regions show that the herbivory in freshwater macrophytes is significant and can reduce the plant biomass (Bakker et al 2016) and plant abundance (Wood et al 2017) by 44-48% These generalizations do not consider the effect and the role of invertebrate herbivores on macrophytes of Neotropical wetlands, because there is little. MARTÍNEZ and CELESTE FRANCESCHINI to free floating macrophytes (Adis and Junk 2003, Poi de Neiff and Casco 2003, Sosa et al 2007, Franceschini et al 2010, 2013, Braga et al 2013, Martinez et al 2013) These studies show that invertebrate herbivores can feed high amounts of freshwater macrophyte biomass and that the abundance and magnitude of the damage caused by herbivores vary significantly between the growth and decay periods of the macrophyte populations (Braga et al 2013, Franceschini et al 2010, 2013). H. nymphoides and N. indica have been mentioned as weeds in the irrigation channels and cultivated rice paddies (Lallana 2005)

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