# Assessing the Functional Response to Streamside Fencing of Pastoral Waikato Streams, New Zealand
## 1 Introduction
Therefore, assessing the success or failure of restoration activities becomes a question of not only what to measure, but when to measure. In regards to what to measure, overall stream health is characterised by a combination of indicators that describe ecosystem structure and function [PERSON] et al. (2018); [PERSON] et al. (2018). Poor stream health, as a result of land use intensification, for example, is characterised by structural indicators that describe physical habitat, e.g., altered substrate composition and channel shape [PERSON] et al. (2018); [PERSON] et al. (2018); flow regime, e.g., altered velocities, [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018); water quality, e.g., increased water temperature and nutrient concentrations; [PERSON] et al. (2018); [PERSON] et al. (2018) and biotic communities such as microorganisms and macroinvertebrates, e.g., more pollution-tolerant communities, lower numbers of taxa and higher algal biomass, [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018). While less commonly applied, functional indicators describe stream ecosystem processes, whereby poor stream health as a result of land use intensification, for example, is described by changes in the rates of organic matter retention and decomposition, and changes in ecosystem metabolism [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018). For example, [PERSON] et al. [PERSON] et al. (2018) showed that retention of coarse particulate organic matter (a major resource subsidy for invertebrate communities) is low in small pastoral streams due to a lack of in-stream structures, such as wood and roots provided by bank and riparian vegetation. Similarly, [PERSON] et al. [PERSON] et al. (2018) found that gross primary production (GPP) was positively correlated to light in agricultural streams, due to a lack of riparian shading. Reviews show that ecosystem metabolism responds to a range of environmental stressors related to a lack of established riparian vegetation, such as increased GPP and ER with increased nutrient enrichment, warmer water temperatures and increased sunlight [PERSON] et al. (2018); [PERSON] et al. (2018). To support the use of functional indicators in stream health assessments, [PERSON], [PERSON] and [PERSON] [PERSON] et al. (2018) proposed a framework to assign organic matter decomposition and ecosystem metabolism values to management bands (i.e., \"healthy\", \"satisfactory\" and \"poor\"). A \"healthy\" stream ecosystem showed characteristics close to unmodified conditions (e.g., closed canopy, lower water temperatures, moderate rates of GPP, ER and organic matter decomposition), whereas a stream ecosystem classified as \"poor\" showed characteristics typical of modified or impacted systems (e.g., open canopy, pasture sites, higher (or lower) rates of GPP, ER and organic matter decomposition). To further support the use of organic matter decomposition as a functional indicator and address the inherent variability in decomposition due to organic matter type [34], [PERSON] et al. [35] proposed cotton strip assays as a standardised measure of organic matter decomposition potential. Cotton strips, like leaf litter, are comprised predominantly of cellulose, but unlike leaf litter, do not contain inhibitory substances that can constrain processing by microbes or invertebrates. As such, cotton strip decomposition reflects the cellulose decomposition potential of streams and is primarily driven by the colonisation of resident microbes [36; 37]. In general, cotton strip decomposition rates are higher in streams with higher temperatures, higher nutrient concentrations and high sediment input (i.e., indicative of \"poor\" ecosystem health), and lower in streams with a \"healthy\" ecosystem [35; 38; 39].