Erratum: Habitat and seasonal distribution of Odonata (Insecta) of Mula and Mutha river basins, Maharashtra, India

Catchment landscape degradation and habitat modifications of freshwater ecosystems are a primary cause of biodiversity loss in riverine ecosystems all over the world. Many elements of the flora and fauna of freshwater ecosystems are sensitive to the changes in catchment land use and habitat modification. These sensitive taxa are also reliable indicators of freshwater ecosystem health. In the current study we investigate the seasonal and habitat distribution of Odonata (Insecta) across riparian land use types in Mula and Mutha river basins, northern Western Ghats, Maharashtra. There was a difference in the species composition across land use types and across seasons with highest diversity and abundance during the post monsoon period. The highest Odonata diversity was observed in urban areas followed by forest and agriculture fields. There was a loss of 31% of the odonate fauna in the study area over 50 years which could be due to rapid industrialization and urbanization of the region and consequent degradation of freshwater ecosystems. The significance of catchment land use on Odonata diversity and its value in landscape monitoring is discussed.

Trophic state of lakes has been related to catchment land use, but direct links between phytoplankton taxa and land use are limited. Phytoplankton composition, represented by relative cell abundance of phyla, was measured over a period of 4 years in 11 lakes in the Rotorua region, New Zealand. The lakes differed in morphometry, trophic state and land use (as percentage catchment area). We tested whether relative proportion of land uses, indirectly representing relative nutrient loading, was the overarching driver of phytoplankton composition. Trophic state was correlated negatively with native forest and positively with pasture and urban area. Cyanoprokaryota were correlated negatively with native forest and positively with pasture and trophic state, Chlorophyta were correlated positively with native forest and urban land use and negatively with pasture and trophic state, and Bacillariophyta were positively correlated with dissolved reactive silica to dissolved inorganic nitrogen (Si:DIN) and Si to dissolved reactive phosphorus (Si:DRP) ratios. Lakes with higher nutrient loads had higher trophic state and Cyanoprokaryota dominance. Chlorophyta were negatively correlated with Cyanoprokaryota and Bacillariophyta, suggesting competition amongst these groups. Our results apply to lakes potentially subject to changes in catchment land use, which may have implications for trophic state, phytoplankton composition and Cyanoprokaryota blooms.

River restoration is a central issue of present-day River Basin Management. Unfortunately, many studies have shown limited ecological improvements, hypothesizing catchment influences and missing donor populations as main impeding factors. This study evaluates the ecological status after restoration at 46 river reaches in light of catchment influences upstream. Three groups of environmental parameters were investigated: (i) riparian land use and (ii) physical habitat quality in different lengths upstream of the restorations and (iii) land use in the whole catchment upstream. Ecological quality ratios of standardized fish, invertebrate and macrophyte samples were used as response variables. The results imply that sub-catchment variables influence the ecological status more than local habitat improvements. In particular, fish and invertebrate ecological status was positively linked to percent deciduous forest upstream of restored sites, while macrophytes revealed an opposite trend. Furthermore, we found a strong linkage of site-scale ecological status and physical habitat quality up to 5 km upstream of the restorations; the more natural were riparian land use and river habitat quality upstream, the higher was the chance of a good ecological quality in restored reaches. We conclude that site-scale restoration measures are likely to be unsuccessful, if the sub-catchment physical habitat upstream is degraded.

A major threat to freshwater taxon diversity is the alteration of natural catchment Land use into agriculture, industry or urban areas and the associated eutrophication of the water. In order to stop freshwater biodiversity loss, it is essential to quantify the relationships between freshwater diversity and catchment Land use and water nutrient concentrations. A literature survey was carried out on biodiversity data from rivers and streams. Fish and macroinvertebrates were selected as focal groups as they are widely used as indicator species of river and stream health. Only published data were selected that (a) compared data found at impaired sites with a pristine reference situation (either in time or space), (b) clearly defined the stressors studied (Land use cover and/or nutrient concentrations), and (c) clearly defined biodiversity (number of native species, species lists or IBI‐scores). The number of native taxa found in each study was transferred in an index of relative taxon richness (RTR) ranging from 0 (severely altered) to 100 (pristine reference conditions). Only those taxa were included that were (at least) present in the most pristine situation. This made it possible to combine, compare and analyse results from different studies. Catchment Land use was expressed as the percentage of non‐natural Land use (agriculture, industry, housing or mining). As a measure of nutrients, the concentrations of NO3, NH4, PO4, total N and total P in the river and stream water were used. Over 240 published articles have been studied, but only 22 met the criteria described above and could be used for further analysis. This study showed that altered catchment Land use has a major effect on freshwater biodiversity and that the rate of species loss is serious; on average every 10% of lost natural catchment Land use cover leads to a loss of almost 6% (±0.83) of the native freshwater fish and macroinvertebrate species. Copyright © 2008 John Wiley & Sons, Ltd.

Summary The societal value, ecological importance and thermal sensitivity of stream‐dwelling salmonids have prompted interest in adaptive management strategies to limit the effects of climate change on their habitats. Additionally, in northern temperate regions, the management and restoration of riparian broadleaf forest is advocated increasingly to dampen variations in stream water temperature and discharge, but might have collateral effects on salmonids by changing allochthonous subsidies. Here, in a cross‐sectional analysis of 18 temperate headwaters with different riparian and catchment land use, we use classical fisheries data alongside stable isotope ratios in salmonids and their macroinvertebrate prey to examine whether increasing catchment cover of broadleaf trees could (i) increase the density, biomass and size of salmonids, (ii) increase brown trout (Salmo trutta) dietary reliance on production of terrestrial origin and (iii) mediate allochthonous energy flux between aquatic macroinvertebrates and brown trout. Contrary to expectation, catchment broadleaf cover had no systematic effect on salmonid density or individual size, although salmonid biomass was lowest in streams draining non‐native conifers. Moreover, there was no major effect of land use on the dependence of S. trutta on terrestrial production: averaged across all sites, trout used more production from in‐stream (62 ± 3%: mean ± 1 SE) than terrestrial (38 ± 3%) sources. Dependence on terrestrial production varied more substantially among individual streams than with riparian land use, mirroring site‐specific patterns observed in macroinvertebrates. Although increased broadleaf cover could benefit salmonids by offsetting the impacts of warming related to climate change, these results imply that broadleaf restoration along temperate, upland headwaters is neutral with respect to salmonid biomass, density and terrestrial subsidies. In contrast, the use of non‐native conifers for stream shading could have negative effects on salmonid production. Knowledge of the ecological implications of climate change adaptation remains rudimentary, and we advocate further evaluations like ours not only for fresh waters, but for ecosystems more generally.

Disentangling environmental drivers of benthic invertebrate assemblages: The role of spatial scale and riverscape heterogeneity in a multiple stressor environment

Stream microhabitats are strongly influenced by adjacent terrestrial land use and other anthropogenic disturbances. Therefore, sensitive stream fauna can be highly imperiled. We investigated relative susceptibility of stream-associated salamanders to riparian land use by studying species-specific responses that influence community assembly. The Piedmont and Blue Ridge ecoregions of the southeastern United States have high aquatic biodiversity, centuries of land use, and increasingly extensive urbanization. We surveyed low-order streams in these regions for salamanders across four riparian land uses (forests, agricultural, residential, and urban) and assessed 15 habitat variables at each sampling site. We found that forested streams were more diverse compared to streams affected by riparian land uses. Our study showed two distinct assemblages of salamanders in response to riparian land use: forest-dependent, large-bodied, long-lived species sensitive to riparian land uses (disturbance avoiders) and cosmopolitan, small-bodied, short-lived species that are relatively resistant to impacts of riparian land uses (disturbance tolerants). These assemblages varied in composition between the ecoregions, with Blue Ridge harboring more land-use–intolerant species. Results indicated that multiple habitat features of the riparian zone (canopy cover, canopy height, leaf litter cover), and stream geomorphology (bank complexity, streambed heterogeneity, sedimentation) are dramatically altered by riparian land uses, and influence the assemblage structure of salamanders. Riparian buffers in both ecoregions are largely unprotected (70% in Blue Ridge, 96% in Piedmont) and are possibly threatened with anthropocentric land uses. Results suggested that conservation of stream salamander communities should be strengthened with protection and restoration of riparian forests, connectivity among riparian forests, and soil-conservation practices.

Detecting land use and land management influences on catchment hydrology by modelling and wavelets

Riparian land uses affect the dry season soil CO2 efflux under dry tropical ecosystems

Despite the presence of laws, guidelines and policies regulating riparian land use, the Nzovwe River catchment is facing rampant undesirable land use within 60m of the buffer zone. This study was set to investigate the drivers of undesirable land use in the catchment. Questionnaires and key informant checklists were used to collect primary data from heads of households and key informants respectively. Statistical Package for Social Sciences was used to perform descriptive and inferential analyses of data. A content analysis was used to analyse key informants’ data. The Geographical Information System (GIS) was used to obtain and analyse land use images of the study area. Results as per key informants’ perspective revealed that lack of political will, administrative fragmentation, limited reallocation compensation funds, law ambiguities and poor land use planning are the drivers of undesirable land use in the catchment. The heads of households argued that undesirable land use in catchment is driven by poor governance (69.4%), negligence (52.4%), ignorance (35.3%), increased demand for land (52.9%), lack of LUP (15.1%), poverty (36.7%), law ambiguities (2.4%) and lack of political will (8.3%). We recommend that the government should emphasize the enhancement of social learning, participatory LUP and research-based policies

The impact of riparian land use on the stream insect communities was studied at Kudremukh National Park located within Western Ghats, a tropical biodiversity hotspot in India. The diversity and community composition of stream insects varied across streams with different riparian land use types. The rarefied family and generic richness was highest in streams with natural semi evergreen forests as riparian vegetation. However, when the streams had human habitations and areca nut plantations as riparian land use type, the rarefied richness was higher than that of streams with natural evergreen forests and grasslands. The streams with scrub lands and iron ore mining as the riparian land use had the lowest rarefied richness. Within a landscape, the streams with the natural riparian vegetation had similar community composition. However, streams with natural grasslands as the riparian vegetation, had low diversity and the community composition was similar to those of paddy fields. We discuss how stream insect assemblages differ due to varied riparian land use patterns, reflecting fundamental alterations in the functioning of stream ecosystems. This understanding is vital to conserve, manage and restore tropical riverine ecosystems.

AimThe extent to which bacterial communities exhibit biogeographic patterns in their distribution remains unclear. We examined the relative influence of factors including geographic distance, latitude, elevation and catchment land use on the distribution and taxon richness of stream bacterial communities across New Zealand.LocationBacterial communities were collected from biofilm growing on submerged rocks in 244 streams. Sample sites spanned a north–south gradient of over 970 km, an elevational gradient of c. 750 m and were collected from a variety of catchment types across New Zealand.MethodsWe used automated ribosomal intergenic spacer analysis, a DNA fingerprinting technique, to characterize the structure and taxon richness of each bacterial community. Key attributes relating to sample location, upstream catchment land use and a suite of additional environmental parameters were collected for every site using GIS procedures. Univariate correlations between measures of bacterial community structure and latitude, elevation and distance were examined. Variance partitioning was then used to assess the relative importance of purely spatial factors versus catchment land use and environmental attributes for determining bacterial community structure and taxon richness.ResultsBacterial taxon richness was related to the geographic location of the sample site, being significantly greater at latitudes closer to the equator and reduced at higher elevations. We observed distance decay patterns in bacterial community similarity related to geographic distance and latitudinal distance, but not to elevational distance. Overall, however, bacterial community similarity and taxon richness was more closely related to variability in catchment land use than to climatic variability or geographic location.Main conclusionOur data suggest that stream biofilm communities across New Zealand are more influenced by catchment land use attributes than by dispersal limitation.

Iron (Fe) concentrations are increasing in lakes on a wide geographical scale, contributing to recent browning of lake waters. As available time series on lake-water Fe concentrations are relatively short, covering the past few decades only, varved lake sediments may provide extended and precisely dated records to study temporal Fe dynamics in lakes in response to environmental drivers, such as changes in catchment land use and atmospheric sulphur deposition. Here, we present and discuss temporal changes in Fe speciation and accumulation rates during the last three centuries as revealed by sub-annually resolved X-ray absorption spectroscopy analyses of varved sediments from three lakes in southern Finland. Iron speciation in sediments is dominated by Fe-bearing silicate fractions in two of the lakes, while the third lake has contributions of organically complexed Fe and Fe-(oxy)hydroxides. Long-term changes in sediment Fe accumulation correspond with documented shifts in land use from agriculture to spruce forestry in the lake catchments, and in one of the lakes with water-level lowering. An overall poor correspondence between monitored aqueous Fe concentrations and sediment-inferred Fe accumulation rates is likely linked to the dominance in the sediments of particulate Fe phases that are not prevalent in suspended form in the water column. This suggests that sediment records are unsuitable for reconstructions of past lake-water Fe concentrations in these lakes. However, the study provides valuable insight into how major land-use changes in the past have affected both the supply and speciation of Fe accumulated in lake sediments.

SummaryLakes and reservoirs bury large quantities of organic carbon (C) and nutrients (nitrogen,N; phosphorus,P) in their sediments, especially when expressed relative to the small area they occupy. Global estimates ofCand nutrient burial rates in reservoirs require a quantitative understanding of the wide variation in the rates and ratios at whichC,NandPare sequestered in sediments.We examined how catchment and reservoir characteristics relate to sediment organicC,NandPconcentrations, stoichiometric burial ratios (C : P,C : N,N : P) and burial rates in 13 small reservoirs across a catchment land use gradient in theMidwesternUnitedStates.SedimentPconcentrations were positively correlated with urban catchment land use and negatively correlated with agricultural catchment land use. Stoichiometric burial ratios varied with catchment land use. BothN : PandC : Pwere positively correlated with agricultural land use, while these ratios were negatively correlated with urban land use and forested land use.In general, rates ofC,NandPburial per unit lake area were not related to land use in the catchment, but were all positively correlated with catchment area to lake area ratios. Results from our study reservoirs suggest that reservoir burial rates are more tightly coupled with morphometric catchment characteristics than with land use.Our results suggest that small reservoirs are regionally and globally significant for biogeochemical processing. However, regional variation requires that much more comprehensive sampling is needed for accurate estimates of global element burial rates.

We explored land use, fish assemblage structure, and stream habitat associations in 20 catchments in Opequon Creek watershed, West Virginia. The purpose was to determine the relative importance of urban and agriculture land use on stream biotic integrity, and to evaluate the spatial scale (i.e., whole-catchment vs riparian buffer) at which land use effects were most pronounced. We found that index of biological integrity (IBI) scores were strongly associated with extent of urban land use in individual catchments. Sites that received ratings of poor or very poor based on IBI scores had > 7% of urban land use in their respective catchments. Habitat correlations suggested that urban land use disrupted flow regime, reduced water quality, and altered stream channels. In contrast, we found no meaningful relationship between agricultural land use and IBI at either whole-catchment or riparian scales despite strong correlations between percent agriculture and several important stream habitat measures, including nitrate concentrations, proportion of fine sediments in riffles, and the abundance of fish cover. We also found that variation in gradient (channel slope) influenced responses of fish assemblages to land use. Urban land use was more disruptive to biological integrity in catchments with steeper channel slopes. Based on comparisons of our results in the topographically diverse Opequon Creek watershed with results from watersheds in flatter terrains, we hypothesize that the potential for riparian forests to mitigate effects of deleterious land uses in upland portions of the watershed is inversely related to gradient.