title: Size matters: implications of the loss of large individuals for ecosystem function

authors: Norkko, Alf

subjects: ecosystem ecology

abstract: Size is a fundamental organismal trait and an important driver of ecosystem functions. Although large individuals may dominate some functions and provide important habitat structuring effects, intra-specific body size effects are rarely investigated in the context of BEF relationships. We used an in situ density manipulation experiment to explore the contribution of large, deep-burrowing bivalves to oxygen and nutrient fluxes across the sediment-water interface. By manipulating bivalve size structure through the removal of large individuals, we held species identity constant, but altered the trait characteristics of the community. The number of large bivalves was the best predictor of ecosystem functioning. Our results highlight that (a) accounting for body size provides important insights into the mechanisms underpinning biodiversity effects on ecosystem function, and (b) if local disturbances are recurrent, preventing individuals from reaching large sizes, the contribution of large adults may be lost, with largely unknown implications for ecosystem functionality.

text: Size matters: implications of the loss of large individuals for ecosystem function Size is a fundamental organismal trait and an important driver of ecosystem functions. Although large individuals may dominate some functions and provide important habitat structuring effects, intra-specific body size effects are rarely investigated in the context of BEF relationships. We used an in situ density manipulation experiment to explore the contribution of large, deep-burrowing bivalves to oxygen and nutrient fluxes across the sediment-water interface. By manipulating bivalve size structure through the removal of large individuals, we held species identity constant, but altered the trait characteristics of the community. The number of large bivalves was the best predictor of ecosystem functioning. Our results highlight that (a) accounting for body size provides important insights into the mechanisms underpinning biodiversity effects on ecosystem function, and (b) if local disturbances are recurrent, preventing individuals from reaching large sizes, the contribution of large adults may be lost, with largely unknown implications for ecosystem functionality.

year: 2013

title: Evidence, interests and argumentation: an environmental policy controversy in a small New Zealand town

authors: Skilling, Peter

abstract: This article examines interactions between different forms of authoritative knowledge and evidence in a public dispute over an environmental problem. It draws on a case set in a small coastal town in New Zealand where the local community had expressed concern over the degradation of a river-mouth estuary caused by catchment management works built in the 1950s to support the farming sector. The estuary historically had been an important economic and cultural treasure for Indigenous Māori, and by the mid-20th century had become a valued recreational and fishing resource for the broader community. This article analyses a moment of dispute in the 1980s between those who called for the restoration of the estuary and those who wished to maintain the status quo. Drawing on an analysis of official reports, media coverage and other public documents, the article shows how the competing parties and their constructions of the collective good accorded authority and weight to specific histories, forms of evidence and kinds of people. The article understands the case not as a dispute between “the people” and “the experts” but rather as a moment where competing blocs drew on specific grammars of justification in their attempts to align their claims with the collective good.

text: Evidence, interests and argumentation: an environmental policy controversy in a small New Zealand town This article examines interactions between different forms of authoritative knowledge and evidence in a public dispute over an environmental problem. It draws on a case set in a small coastal town in New Zealand where the local community had expressed concern over the degradation of a river-mouth estuary caused by catchment management works built in the 1950s to support the farming sector. The estuary historically had been an important economic and cultural treasure for Indigenous Māori, and by the mid-20th century had become a valued recreational and fishing resource for the broader community. This article analyses a moment of dispute in the 1980s between those who called for the restoration of the estuary and those who wished to maintain the status quo. Drawing on an analysis of official reports, media coverage and other public documents, the article shows how the competing parties and their constructions of the collective good accorded authority and weight to specific histories, forms of evidence and kinds of people. The article understands the case not as a dispute between “the people” and “the experts” but rather as a moment where competing blocs drew on specific grammars of justification in their attempts to align their claims with the collective good.

year: 2021

title: The cost of aquatic weed control in the Rotorua Te Arawa Lakes

authors: Champion, Paul

abstract: We will present information on the costs of aquatic weed control in the Rotorua, Te Arawa Lakes and thank all of the people who have willingly given us their estimated costs. Hopefully, this provides guidance on what current activities cost and what future scenarios might be feasible.

text: The cost of aquatic weed control in the Rotorua Te Arawa Lakes We will present information on the costs of aquatic weed control in the Rotorua, Te Arawa Lakes and thank all of the people who have willingly given us their estimated costs. Hopefully, this provides guidance on what current activities cost and what future scenarios might be feasible.

year: 2017