Indicators Of Ecological Change Research Articles

Phytogeographical and biological spectrum of vascular flora as an indicator of ecological changes following clear-cutting in Eastern Serbian beech forest sites

Extreme weather events caused considerable harm to the forest ecosystems in Eastern Serbia over a few hard winters, resulting in widespread ice breaks and ice uprooting. Certain forest stands were severely impacted during the winter of 2014-2015, necessitating clear-cutting measures. This research was conducted in the Timok forest area, through examination of the floristic composition in areas subjected to clear-cutting, including natural beech forests and artificially established conifer stands within beech sites (Helleboro odori-Fagetum moesiacae). A phytogeographical and bioecological analysis was conducted five years after clear-cutting. Changes in ecosystems were assessed by analysing the spectra of area-types and plant life forms, with comparisons drawn to the “Vinatovača” old-growth forest, situated in the submontane beech forest of Eastern Serbia. Descriptive analysis of the phytogeographical and bioecological spectra of vascular flora, alongside multinomial correspondence analysis, revealed an increased presence of species from Eurasian, Mediterranean-sub-Mediterranean, and Pontic area-types, as well as hemicryptophytic, phanerophytic, and therophytic life forms in the clear-cut areas. In contrast, the old-growth forest was colonised by species of Central European and Holarctic area-types, along with geophytic life forms. These findings suggest a shift towards xerothermic microclimates in the clear-cut areas and the stronger influence of the continental climate of Eastern Serbia with its extremes on deforested areas, as well as on the processes of forest ecosystem degradation.

STUDY OF DIVERSITY OF BUTTERFLIES IN BHAGALPUR DISTRICT OF BIHAR IN INDIA

The butterflies are a vital ecosystem component, acting as pollinators, food sources, and good indicators of ecological changes. The present study mainly focuses on identifying butterfly species and their diversity in India?s Bhagalpur district of Bihar. During the survey, 48 butterfly species were recorded. Among these, 19 species were recorded for the first time from Bihar. The surrounding rural areas had rich butterfly diversity comprising 48 species belonging to 5 families compared to the town area, where only 32 species were recorded. A maximum of 16 species were recorded from the nymphalidae family (33.33%). The most abundant species in the target area were Ariadne ariadne, Danaus chrysippus, Euploea core, Junonia almana, Junonia iphita, Leptosia nina nina, Lerodea eufala, Melanitis leda ismene, Papilio demoleus demoleus, and Ypthima huebneri. However, a few species, such as Cigaritis vulcanus, Curetis acuta, Iambrix salsala, and Spialia galba, were rarely found. Maximum diversity was observed in winter, whereas minimum diversity was observed in summer.. KEYWORDS :Butterfly, Diversity, New Records, Nymphalidae

Species composition in assemblages of the family Unionidae Rafinesque, 1820 (Mollusca: Bivalvia) as an indicator of ecological changes in water bodies of Central Polissia, Ukraine

Though Ukraine is one of the countries with insufficient water supply, the northern region of central Polissia has a dense river network. The region’s major rivers – Teteriv, Sluch, Ubort, and Uzh – have undergone significant anthropogenic change. Water pollution has adversely affected their fauna, including the Unionidae (Mollusca: Bivalvia). This study has monitored these changes, and was conducted in two stages. A total of 78 sites with habitats typical for the Unionidae were examined; 45 in 1998–2013, of which 24 were resampled in 2019–2020, and a further 33 were sampled at the same time. Six native species generally characteristic of Ukraine (Unio pictorum Linnaeus, 1758, U. tumidus Philipson, 1788, U. crassus Philipsson, 1788, Anodonta anatina Linnaeus, 1758, A. cygnea Linnaeus, 1758, and Pseudanodonta complanata Rossmassler, 1835) were recorded. While nearly all sites examined in 1998–2013 held some unionids, by 2019–2020, they were recorded in only 62.5% out of the total number of sites in Sluch River basin, 80% in Teteriv River, 40% in Ubort River, and 62.5% in Uzh River. The species richness at sites where unionids were recorded had also declined. Pseudanodonta complanata, recorded in every surveyed basin in 1998–2013, was not observed at any of the sites examined in 2019–2020. In 23 out of the 24 re-examined sites, the extinction of one or more Unionidae species was recorded. It is evident that the role of these large mussels as ecosystem engineers is being compromised.

Influence of urbanisation on the phenology of evergreen coniferous and deciduous broadleaf trees in Madrid (Spain)

Plant phenology plays a crucial role in terrestrial ecosystems and is a key indicator of ecological changes. It is influenced by alterations in meteorological conditions at micro- and mesoscale in cities as a result of urbanisation and the intensification of anthropogenic activities. One example is the urban heat island (UHI), i.e. the increase in temperature in city cores compared to their surroundings. In this study, we used plant phenological data from the High-Resolution Vegetation Phenology and Productivity dataset of the Copernicus Land Monitoring Service to explore the relationship between urbanisation intensity (i.e., proportion of built-up area) and the phenology and productivity of broadleaf deciduous and evergreen coniferous trees in the city of Madrid and its surroundings, one of the largest metropolitan areas in Europe. We found the average start of season date advanced by 0.79–11.79 days in broadleaf deciduous trees in highly urbanised areas, and was delayed by 5.77–9.16 days in evergreen coniferous trees. Although differences were also observed for the end and length of the growing season, these patterns showed great interannual variability. Both broadleaf deciduous and evergreen coniferous trees were most productive in highly urbanised areas. Although previous studies have explored the response of different land-cover types to urbanisation, to our knowledge, none have looked at this relationship at a fine spatial scale in a Mediterranean city with different vegetation functional groups. The analysis of more specific classes of vegetation enables a better understanding of the phenological response of vegetation to urbanisation intensity.

First steps in the ecological flow determining for Latvian rivers

Abstract This study analyses the impact of small hydropower plants (HPP) on fish in three Latvian transboundary river basin districts. The MesoHABSIM habitat simulation model was applied to seven Latvian lowland rivers regulated by HPP, four of which belong to the salmonid river type and three to the cyprinid type. Daily stream flow time series for 1961–2018 were used for flow regime calculations in reference (unimpacted) and altered (impacted by HPP operation) flow conditions. Conditional habitat suitability model/criteria for fish were used to assess a potentially available habitat at different flow conditions. Brown trout (Salmo trutta) for salmonid rivers and chub (Squalius cephalus) for cyprinid rivers were selected as case examples to show habitat suitability for different stream types. The authors found significant differences in habitat availability for salmonid and cyprinid rivers, indicating that ecological flows must be calculated separately for fast- and slow-flowing rivers. This study is the first attempt in Latvia to set ecological flow values not only using hydrological calculations but also biological data as an indicator of ecological changes.

Animal Coloration in the Anthropocene

Natural habitats are increasingly affected by anthropogenically driven environmental changes resulting from habitat destruction, chemical and light pollution, and climate change. Organisms inhabiting such habitats are faced with novel disturbances that can alter their modes of signaling. Coloration is one such sensory modality whose production, perception and function is being affected by human-induced disturbances. Animals that acquire pigment derivatives through diet are adversely impacted by the introduction of chemical pollutants into their environments as well as by general loss of natural habitat due to urbanization or logging leading to declines in pigment sources. Those species that do manage to produce color-based signals and displays may face disruptions to their signaling medium in the form of light pollution and turbidity. Furthermore, forest fragmentation and the resulting breaks in canopy cover can expose animals to predation due to the influx of light into previously dark environments. Global climate warming has been decreasing snow cover in arctic regions, causing birds and mammals that undergo seasonal molts to appear conspicuous against a snowless background. Ectotherms that rely on color for thermoregulation are under pressure to change their appearances. Rapid changes in habitat type through severe fire events or coral bleaching also challenge animals to match their backgrounds. Through this review, we aim to describe the wide-ranging impacts of anthropogenic environmental changes on visual ecology and suggest directions for the use of coloration both as an indicator of ecological change and as a tool for conservation.

Vertical Biogeography and Realized Niche Traits of Living Coccolithophore Community in the Eastern Indian Ocean

AbstractCoccolithophores are crucial components of marine calcifying microalgae and found to be important indicators of ecological changes. The interannual scale and vertical biogeography of springtime living coccolithophore communities were determined in the chronically under‐sampled eastern Indian Ocean (EIO) during seven consecutive years (spring 2011–2018). In addition, we quantified the realized ecological niches of dominant coccolithophore species in the region based on the ecological modeling method (MaxEnt statistics). Results indicated the interannual mean coccolithophore abundance ranged 4,306–11,140 cells L−1. The ecologically important species such as Gephyrocapsa oceanica, Emiliania huxleyi, Algirosphaera robusta, Florisphaera profunda, Umbilicosphaera sibogae, and Umbellosphaera irregularis were identified as dominant species in the coccolithophore community. Based on the ratios of coccoliths and plated coccolithophores, we observed coccolith detachment rates showed a valley near deep chlorophyll maximum layer and peaked in the surface or bottom of euphotic layer which was potentially relevant to near‐surface circulations, nutrients and light availability. From applying the ecological modeling method, we quantified three types of realized niches in coccolithophore species based on mean niche (μ) and breadth of niche (σ) which were consistent with their conventionally vertical biogeography. Our data set could be further incorporated into climatic ecological models.

Diversity of ants (Hymenoptera, Formicidae) along a heavy metal pollution gradient: Evidence of a hump-shaped effect

Abstract Ants, as indicators of ecological changes, are widely used in land management and environmental monitoring. At the same time, effects of industrial pollution are less known compared to many other stressors. We studied variations in habitat variables and ant diversity near the Karabash copper smelter (KCS) in Russia, in 2009 and 2014. Pitfall traps were set up at 10 birch forest sites (3 plots per site and 5 traps per plot) located to the north and south of the smelter within a 1–32-km range, with two samplings per season (June and August). The tree height, stand basal area, species richness of the field and moss layers, and the cover of the field layer decreased towards the smelter. The vegetation almost disappeared at the industrial barren close to KCS. In total, 21 ant species of 7 genera were registered. The highest species richness, diversity, and total occurrence of ants were observed in the transitional zone between moderately polluted forest habitats and industrial barren. Ant diversity and occurrence showed the same pattern in different years. Our results conform to the intermediate disturbance hypothesis predicting the greatest diversity at intermediate frequencies or intensities of disturbance or environmental change. Apparently, contaminant exposure affects ant communities near KCS indirectly, through habitat transformation. The study emphasizes the need for thorough planning of field studies of pollution effects on ants with examination of the full range of exposures. In addition, the nonlinear pattern of diversity and abundance of the ant community along the pollution gradients suggests caution, when assessing the magnitude of human impact and the state of ecosystems with ants as bioindicators.

The Seasonal Variability in The Genus-Family Structure of Free-Living Nematode Communities in Organic Shrimp Farming Ponds, Ca Mau Province

The Seasonal Variability in The Genus-Family Structure of Free-Living Nematode Communities in Organic Shrimp Farming Ponds, Ca Mau Province

Factors affecting the distribution of Pluchea dioscoridis (L.) DC. and its associated species in Gharbia Governorate, Nile Delta, Egypt.

Pluchea dioscoridis is a perennial ruderal shrub. It has been classified as a weed controller due to its bushy growth, medicinal plant due to its strong antioxidant and anti-liver cancer activity and a phytoremediator plant. The present work aims to study the environmental factors affecting the distribution and common associated species of P. dioscoridis in Gharbia governorate, Nile Delta, Egypt. It aims also to assess the diversity and behavior of the common species along the different environmental factors. Seventy three stands, representing four common urban habitats (wastelands, railway sides, canal and drain banks), were selected. In each stand; the florisitic composition and cover of the studied species and its common associated species were estimated. Seventy-two species were recorded as being associated with P. diosocridis. Therophytes were the most represented, while parasites were the least. Mediterranean taxa had the highest chorological contribution. The highest coverage percentage of P. dioscoridis was recorded in the canal banks. TWINSPAN and DCA techniques led to the recognition of four vegetation groups; these groups were indicated by Persicaria salicifolia (A); Echinochloa stagnina and Chenopodium album (B); Arundo donax (C) and P. dioscoridis (D). Vegetation group D, which occupied wastelands, was the most diverse, while VG B occupied drain banks, was the least diverse. Soil analysis indicated that VG A occupied canal banks had the highest values of OM (7.7%) and P (41.2 mg100g-1), but the lowest water holding capacity (20.8%), Cl (0.08%), CO3 (0.07%) and HCO3 (0.04%). Canonical Correspondence Analysis (CCA) showed that chloride, electrical conductivity, total nitrogen, carbonate, and calcium cations were the most effective environmental variables on the distribution of P. dioscoridis and its associated species in the study area. This study may be a beneficial tool to use P. dioscoridis as indicator of ecological change and to estimate the relationship between soil variables and wild communities of it.

Drone Monitoring of Breeding Waterbird Populations: The Case of the Glossy Ibis

Waterbird communities are potential indicators of ecological changes in threatened wetland ecosystems and consequently, a potential object of ecological monitoring programs. Waterbirds often breed in largely inaccessible colonies in flooded habitats, so unmanned aerial vehicle (UAV) surveys provide a robust method for estimating their breeding population size. Counts of breeding pairs might be carried out by manual and automated detection routines. In this study we surveyed the main breeding colony of Glossy ibis (Plegadis falcinellus) at the Doñana National Park. We obtained a high resolution image, in which the number and location of nests were determined manually through visual interpretation by an expert. We also suggest a standardized methodology for nest counts that would be repeatable across time for long-term monitoring censuses, through a supervised classification based primarily on the spectral properties of the image and a subsequent automatic size and form based count. Although manual and automatic count were largely similar in the total number of nests, accuracy between both methodologies was only 46.37%, with higher variability in shallow areas free of emergent vegetation than in areas dominated by tall macrophytes. We discuss the potential challenges for automatic counts in highly complex images.

Expression of mitogen-activated protein kinase double-stranded RNA in cucumber has no apparent effect on the diversity of rhizosphere archaea

AbstractThe expression of mitogen-activated protein kinase (mapk) double-stranded RNA in cucumber is effective in controlling infestations of the root-knot nematode Meloidogyne incognita. However, little is known about the ecological effects of transgenic plants. Here, we analyzed the diversity of 16S rDNA genes derived from the rhizosphere archaea of transgenic cucumber plants as an indicator of ecological change. A total of 17 and 18 operational taxonomic units were detected in the rhizospheres of non-transgenic cucumber and mapk dsRNA-expressing plants, respectively. No significant difference was observed between the two groups according to Shannon and Simpson indices. In soil samples of the two rhizospheres, the dominant group was Crenarchaeota at the phylum level, with Staphylothermus, Methanococcus, Pyrodictium and Sulfolobus the abundant taxa at the genus level. These results suggest that expressing mapk double-stranded (ds) RNA in cucumber has no apparent effect on the diversity of rhizosphere archaea, and provide powerful evidence for the ecological safety of transgenic cucumber expressing mapk dsRNA.

Seaside Sparrows reveal contrasting food web responses to large‐scale stressors in coastal Louisiana saltmarshes

AbstractLarge‐scale ecosystem disturbances can alter the flow of energy through food webs, but such processes are not well defined for Gulf of Mexico saltmarsh ecosystems vulnerable to multiple interacting stressors. The 2010 Deepwater Horizon (DWH) oil spill significantly affected the composition of terrestrial saltmarsh communities in Louisiana, and thus had the potential to alter energy pathways through terrestrial and aquatic food webs, with direct consequences for higher trophic‐level species restricted to these habitats. The Seaside Sparrow (Ammodramus maritimus) is endemic to saltmarshes and relies completely on the habitat and resources they provide; thus, the sparrows can serve as indicators of ecological change in response to disturbances. We analyzed food web pathways for birds residing in oiled and unoiled saltmarshes for the four years following the oil spill by quantifying the bulk carbon and nitrogen stable isotopes and fatty acid profiles of liver tissues, in addition to primary producers (e.g., marsh grasses) and invertebrate consumers representing the major energy resources in these systems. The stable isotope values of primary producers and most invertebrate consumers did not differ between oiled and unoiled sites, suggesting that the energy pathways within the food web were stable in spite of observed declines in these populations following the spill. The tracer profiles of the Seaside Sparrows confirmed that there was a nominal effect of oil on resource use or trophic position (TP). However, we detected significant inter‐annual variation in resource use by these birds; the sparrows occupied a lower TP and exhibited greater assimilation of resources derived from benthic–aquatic relative to terrestrial pathways in 2013 compared to other years. This distinction is likely attributable to the effects of Hurricane Isaac in 2012, whose significant storm surge extensively inundated the saltmarsh landscape. Despite widespread concern for the saltmarsh ecosystem after the DWH event, the significant effects noted at the population level translated into only subtle differences to the flow of energy through this food web. These results demonstrate varying responses to different degrees of landscape‐level disturbance, such as oil and hurricanes, and establish the need to better understand food web dynamics in these saltmarsh ecosystems.

Effects of economics and demographics on global fisheries sustainability.

A good understanding of social factors that lead to marine ecological change is important to developing sustainable global fisheries. We used balanced panel models and conducted cross-national time-series analyses (1970-2010) of 122 nations to examine how economic prosperity and population growth affected the sustainability of marine ecosystems. We used catches in economic exclusive zone (EEZ); mean trophic level of fishery landings (MTL); primary production required to sustain catches (expressed as percentage of local primary production [%PPR]); and an index of ecosystem overfishing (i.e., the loss in secondary production index [L index]) as indicators of ecological change in marine ecosystems. The EEZ catch, %PPR, and L index declined gradually after gross domestic product (GDP) per capita reached $15,000, $14,000, and $19,000, respectively, and MTL increased steadily once GDP per capita exceeded $20,000. These relationships suggest that economic growth and biodiversity conservation are compatible goals. However, increasing human populations would degrade marine ecosystems. Specifically, a doubling of human population caused an increase in the %PPR of 17.1% and in the L index of 0.0254 and a decline in the MTL of 0.176. A 1% increase in human population resulted in a 0.744% increase in EEZ catch. These results highlight the importance of considering social and economic factors in developing sustainable fisheries management policy.

Dispersal in the sub-Antarctic: king penguins show remarkably little population genetic differentiation across their range.

BackgroundSeabirds are important components of marine ecosystems, both as predators and as indicators of ecological change, being conspicuous and sensitive to changes in prey abundance. To determine whether fluctuations in population sizes are localised or indicative of large-scale ecosystem change, we must first understand population structure and dispersal. King penguins are long-lived seabirds that occupy a niche across the sub-Antarctic zone close to the Polar Front. Colonies have very different histories of exploitation, population recovery, and expansion.ResultsWe investigated the genetic population structure and patterns of colonisation of king penguins across their current range using a dataset of 5154 unlinked, high-coverage single nucleotide polymorphisms generated via restriction site associated DNA sequencing (RADSeq). Despite breeding at a small number of discrete, geographically separate sites, we find only very slight genetic differentiation among colonies separated by thousands of kilometers of open-ocean, suggesting migration among islands and archipelagos may be common. Our results show that the South Georgia population is slightly differentiated from all other colonies and suggest that the recently founded Falkland Island colony is likely to have been established by migrants from the distant Crozet Islands rather than nearby colonies on South Georgia, possibly as a result of density-dependent processes.ConclusionsThe observed subtle differentiation among king penguin colonies must be considered in future conservation planning and monitoring of the species, and demographic models that attempt to forecast extinction risk in response to large-scale climate change must take into account migration. It is possible that migration could buffer king penguins against some of the impacts of climate change where colonies appear panmictic, although it is unlikely to protect them completely given the widespread physical changes projected for their Southern Ocean foraging grounds. Overall, large-scale population genetic studies of marine predators across the Southern Ocean are revealing more interconnection and migration than previously supposed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0784-z) contains supplementary material, which is available to authorized users.

Building time-budgets from bioacoustic signals to measure population-level changes in behavior: a case study with sperm whales in the Gulf of Mexico

Evaluating changes in the collective behavior of a population can be an indirect method for inferring organismal responses to changing environmental conditions. Apex predators, such as the sperm whale (Physeter macrocephalus), can provide valuable insights into the ecosystem processes of the deep sea, where little direct observation can be made. Sperm whales are often difficult to observe at sea, as they inhabit deep, offshore waters and spend most of their lives beneath the surface. However, sperm whales are extremely amenable to passive acoustic monitoring, as their vocalizations are well-studied, highly distinguishable, produced regularly, and can be detected at relatively long ranges (>10km). Sperm whales produce distinct clicks in two behavioral contexts (social interaction or foraging/prey capture); thus, we can use acoustic detection of these vocalizations to infer patterns of large-scale, collective behavior, which is similar to studying calling frogs or insects indicating their reproductive phenology. We recorded behaviorally-specific sperm whale vocalizations at three sites in the Northern Gulf of Mexico in July 2010 and 2011. We used these recordings to construct population-level time budgets, an empirical collective metric of behavior, based on the ratio of hours in a day with social clicks to the hours in a day with foraging clicks, and represented this as an “acoustic activity index.” Our index showed significant differences in the proportions of social and foraging behavior across the range of sperm whales in the Northern Gulf of Mexico, and the proportion of social activity increased by more than a factor of two from 2010 to 2011. These differences support previous evidence of differential habitat use by sperm whales in the Gulf of Mexico, and suggest possible changes in environmental conditions between years. Thus, the acoustic activity index may provide a powerful way to evaluate changes in behavior and link them to changing ecological conditions. This novel application of bioacoustics to constructing time budgets and creating a behaviorally-based index at the population scale can serve as an indicator of ecological change, and greatly enhance our ability to understand the behavior and ecology of many acoustically active species.

Short communication: Biochemically active humic substances in contrasting agricultural managements

Because their crucial role in several soil biochemical cycles and their fast response to changes in soil management, extracellular enzymes activities are widely used as sensitive indicators of ecological change and soil quality. The aim of this work was to determine the effects of soil management on the stable pool of soil carbon cycling enzymes as indicators of essential functions. For this, extracellular β-glucosidase enzymes bounded by humic acids (C higher than 104 Da) were used to compare four long-term contrasting agricultural managements in a rainfed olive orchard representative of semi-arid Mediterranean habitats. The study was conducted for 30 years by designing a random-block of four treatments (nude vs. covered soils) and four replicates. Maintaining cover crops through fall, winter and early spring provoked a more stable and active pool of extracellular β-glucosidase in soils only if spontaneous vegetation was managed with mechanical methods. When herbicides were used during 30 years, the pattern of the molecular composition and activity of humus β-glucosidase complexes were similar in covered and nude soils, although higher activity was retrieved in the former. Tillage management increased carbon mineralization and the level of humic substances and the activity of β-glucosidase humic-bound were quite lower than in the rest of treatments. Given the ecological role of extracellular soil carbon cycling enzymes, the characterization of humus β-glucosidase complexes could be an adequate indicator of sustainability of agricultural management systems.

Abrupt shifts in the Gironde fish community: an indicator of ecological changes in an estuarine ecosystem

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 549:137-151 (2016) - DOI: https://doi.org/10.3354/meps11681 Abrupt shifts in the Gironde fish community: an indicator of ecological changes in an estuarine ecosystem Xavier Chevillot1,*, Maud Pierre1, Arthur Rigaud1, Hilaire Drouineau1, Aurélie Chaalali2, Benoit Sautour3, Jérémy Lobry1 1Irstea, UR EABX, 50 Avenue de Verdun, 33612 Cestas Cedex, France 2Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer), Département Ecologie et Modèles pour l’Halieutique, Rue de l’île d’Yeu, BP 21105, 44311 Nantes, France 3Université Bordeaux, Environnements et Paléoenvironnements Océaniques et Continentaux, CNRS UMR 5805 (EPOC), Station Marine d’Arcachon, 2 rue du Pr. Jolyet, 33120 Arcachon, France *Corresponding author: xavier.chevillot@irstea.fr ABSTRACT: For decades, global climate change has directly and indirectly affected the structure and function of ecosystems. Abrupt changes in biodiversity have been observed in response to linear or sudden modifications to the environment. These abrupt shifts can cause long-term reorganizations within ecosystems, with communities exhibiting new functional responses to environmental factors. Over the last 3 decades, the Gironde estuary in southwest France has experienced 2 abrupt shifts in both the physical and chemical environments and the pelagic community. Rather than describing these shifts and their origins, we focused on the 3 inter-shift periods, describing the structure of the fish community and its relationship with the environment during these periods. We described fish biodiversity using a limited set of descriptors, taking into account both species composition and relative species abundances. Inter-shift ecosystem states were defined based on the relationship between this description and the hydro-physico-chemical variables and climatic indices defining the main features of the environment. This relationship was described using generalized linear mixed models on the entire time series and for each inter-shift period. Our results indicate that (1) the fish community structure has been significantly modified, (2) environmental drivers influencing fish diversity have changed during these 3 periods, and (3) the fish-environment relationships have been modified over time. From this, we conclude a regime shift has occurred in the Gironde estuary. We also highlight that anthropogenic influences have increased, which re-emphasizes the importance of local management in maintaining fish diversity and associated goods and services within the context of climate change. KEY WORDS: Ecosystem state · Fish diversity · Estuary · Generalised linear mixed models ·∙ GLMM · Time series · Shift · Inter-shift periods Full text in pdf format Supplementary material PreviousNextCite this article as: Chevillot X, Pierre M, Rigaud A, Drouineau H, Chaalali A, Sautour B, Lobry J (2016) Abrupt shifts in the Gironde fish community: an indicator of ecological changes in an estuarine ecosystem. Mar Ecol Prog Ser 549:137-151. https://doi.org/10.3354/meps11681 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 549. Online publication date: May 10, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Size-based approaches to aquatic ecosystems and fisheries science: a symposium in honour of Rob Peters

This special issue honours Rob Peters’ outstanding contributions to the field of aquatic ecology. It focuses on the size spectrum approach — in which individual organisms, rather than species, are the most basic biological unit — and highlights applications of this approach to fisheries management. The 21 papers in this issue cover three subject areas: (i) the use of size spectra to characterize variation in community structure, (ii) the development of size-based models of ecosystem dynamics to address fisheries questions, and (iii) applications of size-based theory to examine the consequences of variation in predator–prey size relationships, body size – trophic level relationships, and body size – life history relationships. The empirical studies herein demonstrate the utility of size spectra as indicators of population or community structure and for detecting impacts associated with environmental change. Future research focused on refining size-based sampling methods, standardizing metrics and analytical methods, understanding model sensitivity to the underlying assumptions, and comparative studies across ecosystems will enhance our ability to reliably interpret changes in size spectrum characteristics, thus facilitating their use as indicators of ecological change.

Indicators of ecological change (IEC) as efficient tools for managing roe deer populations: a case study

Because of the inaccuracies and biases of population estimates for large herbivores, ‘indicators of ecological change’ (IEC), which allow changes in the animals’ abundance and body condition to be monitored together with ecosystem features, represent an interesting alternative. We used a set of indicators to monitor the relationship between a roe deer (Capreolus capreolus) population and its habitat during a significant increase of hunting pressure in an over-browsed forest of 12.1 km2: the kilometric index, the ovulation rate of adult does, the body mass and jaw length of young and the browsing index. Subsequent to the monitoring results, roe deer density was reduced to a level improving forest regeneration, the animals’ body condition and sustainable game use. Drawing from this successful experience, we caution against a misuse of IEC that could lead to erroneous interpretations. First, the indicators concerning abundance, body condition and impact on the habitat are complementary and necessary to obtain the information needed to efficiently manage populations. Second, managers must consider the values obtained over at least three consecutive years to correctly interpret IEC variations because of their non-linearity and sensitivity to environmental fluctuations.