The Nature Index: A General Framework for Synthesizing Knowledge on the State of Biodiversity

The magnitude and urgency of the biodiversity crisis is widely recognized within scientific and political organizations. However, a lack of integrated measures for biodiversity has greatly constrained the national and international response to the biodiversity crisis. Thus, integrated biodiversity indexes will greatly facilitate information transfer from science toward other areas of human society. The Nature Index framework samples scientific information on biodiversity from a variety of sources, synthesizes this information, and then transmits it in a simplified form to environmental managers, policymakers, and the public. The Nature Index optimizes information use by incorporating expert judgment, monitoring-based estimates, and model-based estimates. The index relies on a network of scientific experts, each of whom is responsible for one or more biodiversity indicators. The resulting set of indicators is supposed to represent the best available knowledge on the state of biodiversity and ecosystems in any given area. The value of each indicator is scaled relative to a reference state, i.e., a predicted value assessed by each expert for a hypothetical undisturbed or sustainably managed ecosystem. Scaled indicator values can be aggregated or disaggregated over different axes representing spatiotemporal dimensions or thematic groups. A range of scaling models can be applied to allow for different ways of interpreting the reference states, e.g., optimal situations or minimum sustainable levels. Statistical testing for differences in space or time can be implemented using Monte-Carlo simulations. This study presents the Nature Index framework and details its implementation in Norway. The results suggest that the framework is a functional, efficient, and pragmatic approach for gathering and synthesizing scientific knowledge on the state of biodiversity in any marine or terrestrial ecosystem and has general applicability worldwide

Life history and species composition of the damselfly assemblage along the urban tract of a river in central Italy

The species composition of the damselfly assemblage and the life history patterns of two Coenagrionidae (Ischnura elegans and Cercion lindeni) were investigated along the urban tract of a river characterized by increasing organic pollution. The assemblage was dominated by generalist species, usually recorded in lentic habitats, rather than by typical riverine species and the proportion of the latter decrease at the most polluted sites. At the end of Winter, the mean size and instar distribution were different between the sampling sites showing that the life history of both species examined were influenced by a degradation of the environmental quality. A longer reproductive period, absence of diapause, and tolerance of low oxygen concentration appear to be key factors that allow generalist species I. elegans and C. lindeni to predominate at the polluted sites

Limnological aspects of an Apennine shallow lake

We present the results of a four-years monitoring program of Lake Duchessa, a small shallow subalpine lake situated at 1788 m a.s.l. in central Apennines (Italy). From 1997 to 2000, during snow free periods, we regularly measured conductivity, pH, macrophyte cover and water transparency. Contemporarily, 4 water samples were collected to determine nutrient (NH3-N, NO 2-N, NO3-N and PO4-P) and phytoplanktonic chlorophyll a concentrations. Taxonomic compositions of aquatic macrophytes, zooplankton and macroinvertebrates were also determined. Inter- and intra-annual variation of water chemistry and phytoplankton biomass were addressed. Lake Duchessa showed some limnological aspects proper to lowland eutrophic situations due to livestock grazing in the watershed pastures and watering in the lake. In particular, nutrient concentration and phytoplankton biomass reached extremely high values, and lake community was relatively poor. However, despite the high nutrient loading, phytoplankton biomass collapsed in August 1997. In the same occasion, lake water became transparent and remained clear until the end of 1999. The occurrence of this clear water phase and its surprising span may be related to the reduction of tench population (due to a natural fish kill observed during the study) and to the extension of Potamogeton pectinatus L. and Myriophyllum spicatum L. cover. Our results support early observations that water transparency (i.e. environmental quality) of eutrophic shallow lakes can be improved also when nutrient loading is not reduced. Many of the Apennine lakes and ponds situated at high altitudes show conditions similar to those of Lake Duchessa. Therefore this study highlights the ecological processes to be considered in a reliable management of these freshwater systems

Effects of a waste water treatment plant on organic matter dynamics and ecosystem functioning in a Mediterranean stream

We studied the effects of a waste water treatment plant on organic matter dynamics in Fosso Bagnatore, a Mediterranean stream near Rome (Italy). Concentrations of dissolved organic carbon and seston, along with the standing crops of coarse benthic organic matter and fine benthic organic matter, were monitored monthly during 2002 in two reaches situated upstream and downstream of a waste water treatment plant effluent. Additionally, we examined two stream functional characteristics: whole stream metabolism, which was measured from diel changes in oxygen concentrations, and nutrient removal, which was Studied by experimental additions of NH4-N, NO3-N and PO4-P. The possible influence of WWTP organic matter alterations on ecosystem functioning was addressed by measuring epilithon characteristics (standing crop, C:N:P ratios and chlorophyll a content). The WWTP effluent caused an increase (several-fold) of DOC and seston concentrations, and FBOM standing crop. moreover it modified their temporal variation. Downstream of the wastewater treatment plant we detected an higher heterotrophic microbial biomass and a correspondent higher community respiration. The uptake of NH4-N, NO3-N and PO4-P was highly variable probably as consequence of the high variability of the compartments involved (e.g. DOC, FBOM, community respiration). We showed that WWTP effluent altered the organic matter dynamics of this Mediterranean-type headwater stream and that these effects were reflected in its ecosystem functioning. Because of the linkage of headwaters to downstream ecosystems and due to their significant role in landscape and catchment processes, the alterations of organic matter dynamics that we detected at a local scale may have important consequences on a broader scale

The alternative stable state concept and the management of Apennine mountain ponds.

1.In mountainous areas of the central Apennines, permanent ponds and small lakes show high concentrations of nutrients causing algal blooms and fish kills. Their degraded condition is at odds with their conservation status since most of them are located within protected areas. Therefore, urgent remedial measures and management of these valuable habitats is required.2.The concept of alternative equilibria potentially provides a scientific framework for management actions in shallow freshwater ecosystems. However, little is known regarding how this concept applies to Apennine ponds.3.This paper examines nutrient, phytoplankton biomass, transparency and macrophyte data from 30 Apennine ponds and shallow lakes. Patterns of soluble reactive phosphorus, dissolved inorganic nitrogen, chlorophyll a and water transparency are consistent with the existence of alternative stable states. The extent of macrophyte cover plays a key role in stabilizing one of the alternative stable states.4.Reducing nutrient inputs from the catchment

Application of an image analysis system to the determination of biomass (ash free dry weight) of pond macroinvertebrates

The absence of a rapid and inexpensive method for estimating macroinvertebrate individual biomass is a limit to the study of freshwater communities, given that traditional methods are time- and money-consuming. We propose an inexpensive method to quickly estimate individual biomass from video-recorded images of pond macroinvertebrates. We used a software that automatically measures several body dimensions (area, perimeter, minor and major axes) on each individual and linear regression to relate these body dimensions to dry weight. Area was found to be the best predictor of dry weight. The method allows individual measures of macroinvertebrates at a reasonable speed and accuracy, and may be useful for biomass size spectra or secondary production studies

Habitat characteristics and Odonata diversity in mountain ponds of Central Italy

In mountainous areas of the central Apennines, permanent ponds and small lakes show high concentrations of nutrients causing algal blooms and fish kills. Their degraded condition is at odds with their conservation status since most of them are located within protected areas. Therefore, urgent remedial measures and management of these valuable habitats is required. 2 The concept of alternative equilibria potentially provides a scientific framework for management actions in shallow freshwater ecosystems. However, little is known regarding how this concept applies to Apennine ponds. 3. This paper examines nutrient, phytoplankton biomass, transparency and macrophyte data from 30 Apennine ponds and shallow lakes. Patterns of soluble reactive phosphorus, dissolved inorganic nitrogen, chlorophyll a and water transparency are consistent with the existence of alternative stable states. The extent of macrophyte cover plays a key role in stabilizing one of the alternative stable states. 4. Reducing nutrient inputs from the catchment, adopting measures to increase and/or restore macrophyte beds, and manipulating fish assemblages are potentially promising strategies for the restoration and conservation of Apennine ponds

Life history and species composition of the damselfly assemblage along the urban tract of a river in central Italy

The species composition of the damselfly assemblage and the life history patterns of two Coenagrionidae (Ischnura elegans and Cercion lindeni) were investigated along the urban tract of a river characterized by increasing organic pollution. The assemblage was dominated by generalist species, usually recorded in lentic habitats, rather than by typical riverine species and the proportion of the latter decrease at the most polluted sites. At the end of Winter, the mean size and instar distribution were different between the sampling sites showing that the life history of both species examined were influenced by a degradation of the environmental quality. A longer reproductive period, absence of diapause, and tolerance of low oxygen concentration appear to be key factors that allow generalist species I. elegans and C. lindeni to predominate at the polluted sites