Rethinking livestock encroachment at a protected area boundary.

The presence of livestock inside protected areas, or "livestock encroachment," is a global conservation concern because livestock is broadly thought to negatively affect wildlife. The Maasai Mara National Reserve (MMNR), Kenya, exemplifies this tension as livestock is believed to have resulted in the declining wildlife populations, contributing to the strict and sometimes violent exclusion measures targeting Maasai pastoralists. However, research embedded in the real-world setting that draws insights from the social-ecological contexts is lacking. In this study, we conducted 19 mo of ecological monitoring covering 60 sites in MMNR and found that cattle presence inside the reserve did not significantly impact most co-occurring wild herbivores at the current intensity. Using the Hierarchical Modeling of Species Communities and Gaussian copula graphic models, we showed that cattle had no direct associations-neither negative nor positive-with nearly all wild herbivores despite frequently sharing the same space. Moreover, we did not detect resource degradation correlated with cattle presence near the MMNR boundary. Given the colonial legacy and land use history of Mara, entering MMNR becomes the only viable option for many herders. These results corroborate the emerging perspective that the ecological impacts of extensively herded livestock on wildlife might be more nuanced than previously thought. To effectively balance the needs of people, livestock, and wildlife, the current rigid livestock exclusion measures need to be reassessed to holistically consider herbivore ecology, local land use history, and modern politics of protected area management.

Climate change increases flowering duration, driving phenological reassembly and elevated co-flowering richness.

Changes to flowering phenology are a key response of plants to climate change. However, we know little about how these changes alter temporal patterns of reproductive overlap (i.e. phenological reassembly). We combined long-term field (1937-2012) and herbarium records (1850-2017) of 68 species in a flowering plant community in central North America and used a novel application of Bayesian quantile regression to estimate changes to flowering season length, altered richness and composition of co-flowering assemblages, and whether phenological shifts exhibit seasonal trends. Across the past century, phenological shifts increased species' flowering durations by 11.5 d on average, which resulted in 94% of species experiencing greater flowering overlap at the community level. Increases to co-flowering were particularly pronounced in autumn, driven by a greater tendency of late season species to shift the ending of flowering later and to increase flowering duration. Our results demonstrate that species-level phenological shifts can result in considerable phenological reassembly and highlight changes to flowering duration as a prominent, yet underappreciated, effect of climate change. The emergence of an autumn co-flowering mode emphasizes that these effects may be season-dependent.

Enhanced remediation of real agricultural runoff in surface-flow constructed wetlands by coupling composite substrate-packed bio-balls, submerged plants and functional bacteria: Performance and mechanisms.

Import of agricultural runoff containing nutrients considerably contributes to eutrophication of receiving water bodies. Surface-flow constructed wetlands (SFCWs) are commonly applied for agricultural runoff purification, but the performance is usually unsatisfactory. In this study, suspended bio-balls filled with zeolite and iron-carbon (Fe-C) composite substrates, submerged macrophyte (Ceratophyllum demersum) and functional denitrifying bacteria were collectively added into SFCW microcosms to enhance the remediation efficiency for real agricultural runoff with high nutrient concentrations and low content of bioavailable organic matter. The bio-ball added SFCWs achieved notably higher pollutant removal efficiencies (21.1%, 80.2% and 47.5% for chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), respectively) than the control (COD: 6.9%, TN: 64.4%, TP: 27.9%), because of the versatile functions of filling materials for pollutant removal. C. demersum plantation (COD: 44.2%, TN: 82.8% and TP: 53.7%) and functional bacteria inoculation (COD: 51.8%, TN: 85.8% and TP: 55.1%) further enhanced the efficiency of the SFCWs for agricultural runoff remediation. Bio-ball addition and C. demersum plantation significantly increased the humification degree and reduced the molecular weight of dissolved organic matter (DOM) in the agricultural runoff. Moreover, the two intensification measures also notably reduced organic and nitrogen contents in the wetland sediment. Remarkable distinction in bacterial community distribution patterns was observed in the SFCW sediment and filling substrates in bio-balls. Keystone genera including Clostridium_sensu_stricto_1 and Bacillus in the zeolite, Sphingomonas and Exiguobacterium in the Fe-C substrates and Sediminibacterium in the sediment might be critical for agricultural runoff remediation in the SFCW microcosms. The study highlights a high potential of the intensified SFCWs by these coupling measures for agricultural runoff remediation.

Current status of coral disease prevalence at Karimunjawa Island: correlation between land zonation and lesion occurrence.

Coral diseases have contributed significantly to the decline of coral populations at both local and global scales. The Karimunjawa Archipelago, located off the coast of Java in Indonesia, is a marine national park with a zonation-based approach, designated by the local government due to its rich coral reef biodiversity. Unfortunately, there is a limited amount of research regarding the prevalence of coral diseases in coral reefs located on the islands. We analyzed the coral reef lesion assemblages at 6 sites within 3 designated zones, namely Tourism, Aquaculture, and Core zones. Our investigation aimed to determine (1) the types, prevalence, and patterns of coral lesions, (2) the correlation between coral cover and lesion prevalence, and (3) the susceptibility of coral taxa to lesions. A significant difference of 80.54% in the total number of coral lesions was observed between the tourism zone (24.34%) and the core zone (10.36%). Fourteen different lesion types were identified; among the non-disease lesions, sediment damage was the most prevalent (9.95%), followed by disease lesions caused by white syndrome (3.7%). A correlation was found between the cover of dominant coral taxa and the prevalence of lesions (disease and non-disease) at all sites. Mean lesion prevalence across all zones ranged from moderate to high categories. These findings present current data on the distribution of coral lesions and their patterns across zones around Karimunjawa Island. Research on the etiology and epidemiology of coral lesions should be promoted to identify ways to prevent the spread of coral diseases in Karimunjawa.

Molecular detection and genetic characteristics of Giardia duodenalis in dairy cattle from large-scale breeding farms in Xinjiang, China.

Giardia duodenalis is an intestinal protozoan that can infect both humans and animals, leading to public health issues and economic losses in the livestock industry. G. duodenalis has been reported to infect dairy cattle, but there is limited information available on large-scale dairy farms in Xinjiang, China. The study collected 749 fresh faecal samples from five large-scale cattle farms in Xinjiang, China. The study used a nested PCR assay of the small subunit ribosomal RNA (SSU rRNA*) gene to determine the presence of G. duodenalis. The results showed that 24.0% (180/749) of dairy cattle were positive for G. duodenalis, with the highest infection rate observed in pre-weaned calves (45.1%, 69/153). Among the 180 G. duodenalis positive samples, three assemblages were identified: assemblage E (n = 176), assemblage A (n = 3) and assemblage B (n = 1). Sixty-nine, 67 and 49 sequences were obtained for the beta-giardin (bg*) gene, the glutamate dehydrogenase (gdh*) gene and the triose phosphate isomerase (tpi*) gene, respectively. Thirteen novel sequences of assemblage E were identified, including five sequences from the bg* gene, four sequences from the gdh* gene and four sequences from the tpi* gene. This study found that 32 G. duodenalis assemblage E isolates formed 26 MLGs, indicating genetic variation and geographic isolation-based differentiation in bovine-derived G. duodenalis assemblage E. These findings provide fundamental insights into the genetic diversity of G. duodenalis in dairy cattle and can aid in the prevention and control of its occurrence in large-scale dairy cattle farms.

Micropolitics of Mental Health Recovery: An Assemblage Analysis of People's Experiences of Becoming Well.

Mental health recovery takes place in a social and material world. However, socio-material contexts have often been absent from recovery studies. The present study was conducted in Norway, a Scandinavian welfare country. We interviewed people at meeting places who had experiences as service users, focusing on their experiences of becoming well, and analyzed their recovery stories using an assemblage framework. Our analysis identified four constitutive dimensions that promote mental health recovery: an atmosphere of togetherness, doings as more than the act, personal development, and integration in society. We discuss how these dimensions might be seen as social, relational, and material forces that create important micropolitics that challenge the individualistic professionalization of the recovery concept.

Colonization, diversity, and seasonality of fishes at pelagic fish aggregating devices.

The pelagic zone of the ocean can be a challenging environment in which to conduct research and as a result we lack the robust baseline abundance and diversity data, compared to what is available in more accessible coastal habitats, to be able to track changes or stressors to the biota in this environment. Many large-scale fisheries target pelagic fish, and much of the information available on these species is based on fisheries-dependent data that may be biased towards hotspots and commercially valuable fishes. Here, a long-term video and visual fish survey was conducted on two subsurface moored fish aggregating devices (FADs) in the pelagic waters of the central Bahamas to determine the feasibility of using moored pelagic FADs as tools for collecting fish abundance and diversity data. A wide range of species was documented, including large migratory fish that are the focus of commercial and recreational fisheries, and smaller often overlooked species on which little abundance or seasonality information exists. We found that FADs colonize quickly and reach a peak stable (albeit seasonally cyclical) abundance and diversity within the first several months after deployment. Species richness was higher in video surveys, but abundance was higher in visual surveys, except for sharks. Our results highlight the need to tailor survey methods to fit the context and study objective, and provide further evidence for the importance of fisheries-independent data in monitoring pelagic species.

"Recovery" in mental health services, now and then: A poststructuralist examination of the despotic State machine's effects.

Recovery is a model of care in (forensic) mental health settings across Western nations that aims to move past the paternalistic and punitive models of institutional care of the 20th century and toward more patient-centered approaches. But as we argue in this paper, the recovery-oriented services that evolved out of the early stages of this liberating movement signaled a shift in nursing practices that cannot be viewed only as improvements. In effect, as "recovery" nursing practices became more established, more codified, and more institutional(ized), a stasis developed. Recovery had been reterritorialized. The purpose of this paper is to examine some of the threads of recovery, from its early days of antipsychiatry activism to its codification into mental health-including forensic mental health-institutions through the lens of poststructuralist philosophers Gilles Deleuze and Felix Guattari. We believe that Deleuze and Guattari's scholarship provides the necessary, albeit uncomfortable, framework for this critical examination. From a conceptualization of recovery as an assemblage, we critically examine how we can go about creating something new, caught in a tension between stasis and change.

The effect of the tidal cycle on the phytoplankton community assemblage in a mangrove-dominated tropical tidal creek.

A comparative assessment of phytoplankton dynamics during low tide (LT) and high tide (HT) was conducted from February 2022 to January 2023 in a tropical mesotidal creek, Manori, Mumbai, India. In total, 124 phytoplankton species were recorded. The HT resulted in greater species richness (124 species) and diversity indices (Shannon-Wiener's index) than the LT (102 species). The Pielou's evenness (J') and Simpson's dominance index (1-D) did not show significant fluctuations with the tides due to the marine phytoplankton species moving rhythmically in and out of the creek with the tides. Overall, the seasonal abundance was maximum during pre-monsoon at HT (5.79 × 103 u/L) and lowest in monsoon at LT (0.45 × 103 u/L), whereas spatial abundance was maximum at S1 (HT- 4.04 × 103 u/L) at HT and lowest at S3 (LT- 0.75 × 103 u/L) at LT. The diatoms dominated in their abundance (1.83 × 103 u/L and 3.82 × 103 u/L in HT) and diversity (77 in LT and 92 in HT). The species such as Coscinodiscus centralis, Coscinodiscus granii, Coscinodiscus radiatus, Triops furca, Melosira varians, Nitzchsia palea, Chaetoceros affinis, Skeletonema marinoi, Stephanocyclus meneghinianus, Planktoniella sol and Skeletonema costatum were the dominant native residents in the creek. SIMPER analysis revealed that the maximum similarity was during the monsoon (47.65%), and the minimum was during the pre-monsoon (38.10%) at LT. However, in HT, the maximum similarity of phytoplankton shifted to post-monsoon (63.85%) and the minimum during the pre-monsoon (46.71%). The mean value of richness (d') and Shannon's diversity (H') showed a moderate phytoplankton diversity in the system. The environmental parameters (water temperature > pH > nitrate > salinity > DO > Alk > silicate) have a greater influence on the distribution of the phytoplankton community with tides as revealed by the Canonical correspondence analysis. Therefore, it has been found that tides play a significant role in the distribution and abundance of the phytoplankton community in a mesotidal creek environment.

Subjectivity through the lens of Guattari: A key concept for nursing.

Félix Guattari, a French philosopher and psychotherapist often recognized for his collaboration with Gilles Deleuze, also published important work of his own. The way he conceptualizes subjectivity and schizoanalysis (later developed into institutional analysis) can incite us to interpret our social contexts differently and to help frame an emancipatory path in nursing. At La Borde, a psychiatric clinic, subjectivity was seen as the real power that lies within the institutions; invisible and flowing through all levels of the hierarchal structure-like waves-each of them unique but still part of the same ocean. Even with its elusive character, this concept can be wielded through psychotherapeutic techniques of analysis which aim to reduce hierarchies, encourage collaborations, decentralize levers of power and promote initiatives that arise from the base. These concepts deserve further exploration when it comes to modern institutional issues like the ones present in Quebec's (Canada) healthcare system. Therefore, this article borrows theorizations elaborated through psychotherapy and applies them to the hospital institution which is seen as an organized, stable structure (the molar line), while paying attention to fluid, changing processes and the multiplicity of desires for transformation (the molecular line), to promote nursing movements that escape and abolish these structures, creating new possibilities and new forms of thinking (the line of flight).

Variations in microbial assemblage between rhizosphere and root endosphere microbiomes contribute to host plant growth under cadmium stress.

IMPORTANCE: In this study, we revealed that the variation in rhizosphere and root endosphere microbial assemblage between host plant ecotypes contribute to their differential abilities to withstand cadmium (Cd) stressors. Furthermore, our study found that phenolic compounds, such as benzenoids and flavonoids, could function as both essential carbon sources and semiochemicals, thereby contributing to the assemblage of rhizosphere microbiome to resist Cd stress. Our findings provide new insights into the mechanisms that drive the differential assemblage of rhizosphere and root endosphere microbiomes to enhance plant growth under abiotic stress.

Sea temperature is the primary driver of recent and predicted fish community structure across Northeast Atlantic shelf seas.

Climate change has strongly influenced the distribution and abundance of marine fish species, leading to concern about effects of future climate on commercially harvested stocks. Understanding the key drivers of large-scale spatial variation across present-day marine assemblages enables predictions of future change. Here we present a unique analysis of standardised abundance data for 198 marine fish species from across the Northeast Atlantic collected by 23 surveys and 31,502 sampling events between 2005 and 2018. Our analyses of the spatially comprehensive standardised data identified temperature as the key driver of fish community structure across the region, followed by salinity and depth. We employed these key environmental variables to model how climate change will affect both the distributions of individual species and local community structure for the years 2050 and 2100 under multiple emissions scenarios. Our results consistently indicate that projected climate change will lead to shifts in species communities across the entire region. Overall, the greatest community-level changes are predicted at locations with greater warming, with the most pronounced effects at higher latitudes. Based on these results, we suggest that future climate-driven warming will lead to widespread changes in opportunities for commercial fisheries across the region.

Increasing stability of a native freshwater fish assemblage following flow rehabilitation.

Stream restorations are increasingly critical for managing and recovering freshwater biodiversity in human-dominated landscapes. However, few studies have quantified how rehabilitative actions promulgate through aquatic communities over decades. Here, a long-term dataset is analyzed for fish assemblage change, incorporating data pre- and post-restoration periods, and testing the extent to which native assemblage stability has increased over time. In the late 1950s, a large capacity dam was installed on Putah Creek (Solano County, CA, USA), which altered the natural flow regime, channel structure, geomorphic processes, and overall ecological function. Notably, downstream flows were reduced (especially during summer months) resulting in an aquatic assemblage dominated by warm-water nonnative species, while endemic native species subsisted at low levels as subordinates. A court-mediated Accord was ratified in 2000, providing a more natural flow regime, specifically for native and anadromous fishes in the stream. The richness of nonnative species decreased at every site following the Accord, while the richness of native species increased or stayed constant. At the three most upstream sites, native species richness increased over time and ultimately exceeded nonnative richness. Native assemblage recovery was strongest upriver, closer to flow releases and habitat restoration activities, and decreased longitudinally downstream. Rank-abundance curves through time revealed that, while species evenness was low throughout the study, dominance shifted from nonnative to native species in the upstream sites coincident with rehabilitation efforts. Mean rank shifts decreased following flow rehabilitation; thus the assemblage became increasingly stable over time following flow rehabilitation. Putah Creek's rehabilitation may represent a model for others interested in improving endemic freshwater communities in degraded ecosystems.

Tree dissimilarity determines multi-dimensional beta-diversity of herbivores and carnivores via bottom-up effects.

Global biodiversity decline and its cascading effects through trophic interactions pose a severe threat to human society. Establishing the impacts of biodiversity decline requires a more thorough understanding of multi-trophic interactions and, more specifically, the effects that loss of diversity in primary producers has on multi-trophic community assembly. Within a synthetic conceptual framework for multi-trophic beta-diversity, we tested a series of hypotheses on neutral and niche-based bottom-up processes in assembling herbivore and carnivore communities in a subtropical forest using linear models, hieratical variance partitioning based on linear mixed-effects models (LMMs) and simulation. We found that the observed taxonomic, phylogenetic and functional beta-diversity of both herbivorous caterpillars and carnivorous spiders were significantly and positively related to tree dissimilarity. Linear models and variance partitioning for LMMs jointly suggested that as a result of bottom-up effects, producer dissimilarities were predominant in structuring consumer dissimilarity, the strength of which highly depended on the trophic dependencies on producers, the diversity facet examined, and data quality. Importantly, linear models for standardized beta-diversities against producer dissimilarities implied a transition between niche-based processes such as environmental filtering and competitive exclusion, which supports the role of bottom-up effect in determining consumer community assembly. These findings enrich our mechanistic understanding of the 'Diversity Begets Diversity' hypothesis and the complexity of higher-trophic community assembly, which is fundamental for sustainable biodiversity conservation and ecosystem management.

The glacier melting process is an invisible barrier to the development of Antarctic subtidal macroalgal assemblages.

Ecological macroalgal succession in glacier-free areas has remained at the pioneer seral stage despite six decades of glacial retreat at Marian Cove, King George Island, Antarctica. With the rapid melting of glaciers in the West Antarctic Peninsula owing to global warming, a massive amount of meltwater is flowing into the coast, creating marine environmental gradients such as turbidity, water temperature, and salinity. This study examined the spatial and vertical distributions (up to a depth of 25 m) of macroalgal assemblages from nine sites in Maxwell Bay and Marian Cove. The macroalgal assemblages were analyzed for six sites located 0.2, 0.8, 1.2, 2.2, 3.6, and 4.1 km away from the glacier, including three sites where the glacial retreat history of Marian Cove could be estimated. To investigate the effects of meltwater, differences in the coastal environment were analyzed based on data collected from five stations located 0.4, 0.9, 3.0, 4.0, and 5.0 km away from the glacier. The macroalgal assemblages and marine environment were divided into two groups-inside and outside the cove-based on the region 2-3 km away from the glacier, which has been ice-free since 1956 and shows significant differences. In the three sites near the glacier front, Palmaria decipiens was dominant, and three to four species were distributed, whereas in the two sites outside the cove, nine and 14 species appeared, respectively, similar to the assemblage of the other three sites in Maxwell Bay. Palmaria decipiens, a representative opportunistic pioneer species in Antarctica, is dominant because of its physiological adaptation despite the high turbidity and low water temperature of the glacier front. This study shows that macroalgal assemblages in Antarctic fjord-like coves respond to glacial retreat and are valuable in understanding the macroalgal succession in Antarctica.

Trait velocities reveal that mortality has driven widespread coordinated shifts in forest hydraulic trait composition.

Understanding the driving mechanisms behind existing patterns of vegetation hydraulic traits and community trait diversity is critical for advancing predictions of the terrestrial carbon cycle because hydraulic traits affect both ecosystem and Earth system responses to changing water availability. Here, we leverage an extensive trait database and a long-term continental forest plot network to map changes in community trait distributions and quantify "trait velocities" (the rate of change in community-weighted traits) for different regions and different forest types across the United States from 2000 to the present. We show that diversity in hydraulic traits and photosynthetic characteristics is more related to local water availability than overall species diversity. Finally, we find evidence for coordinated shifts toward communities with more drought-tolerant traits driven by tree mortality, but the magnitude of responses differs depending on forest type. The hydraulic trait distribution maps provide a publicly available platform to fundamentally advance understanding of community trait change in response to climate change and predictive abilities of mechanistic vegetation models.

Theorising health equity research for people with intersex variance through new materialism.

Health inequalities impact sex-variant people in highly differentiated ways. This is evidenced in much academic and activist intersex research documenting the highly specific forms of inequalities arising from misrecognition, discrimination and human rights abuses inherent to pathologised accounts of non-normative bodies. Important theoretical work further interrogates the implications of sex variant subjectivities, identities and bodies for static or binary notions of both sex and gender. In this paper, we aim to contribute further to this scholarship. We draw upon feminist materialist and Deleuzean-informed understandings of materials or matter to rethink debates over sex-variant subjectivities, identities and bodies in relation to inequalities in health. We argue 'the turn to matter' and associated new materialist theories draw attention to the complex, dynamic relational assemblages and entanglements mutually constituting the affective, embodied and socio-material worlds of intersex people. Informed by these theories, we propose that inequalities can be more fully addressed through a new health equity research agenda that is co-produced with sex-variant people. This agenda will enable a fuller exploration of the unsettling but transformative capacities of intersex matters and meanings with the contextually specific understandings of equity in relation to health and health care.

Prevalence and assemblage of Giardia duodenalis in a case-control study of children under 5 years from Jimma, Southwest Ethiopia.

Giardia duodenalis is a common pathogenic intestinal protozoan parasite with high prevalence in developing countries, especially among children. The distribution of giardia assemblages among humans and their clinical relevance remains controversial. This study aimed to determine the prevalence and assemblage of Giardia among children under 5 years of age in Jimma, Southwest Ethiopia. Employing a case-control design, 606 children presenting with diarrhea at Jimma university medical center and Serbo Health Center were enrolled from December 2016 to July 2018 along with 617 matched controls without diarrhea. Giardia was detected and typed using real-time PCR. Univariate and multivariate regression analysis was performed. The total prevalence of Giardia was 41% (501/1223) and did not differ significantly between cases and controls (40% vs 42%). Prevalence increased by age, with the highest prevalence seen in children aged ≥ 25 months. Children without diarrhea with a history of diarrhea during the last month were more likely to be Giardia positive compared to children with no history diarrhea (OR 1.8 and 95%CI; 1.1-2.9). Regardless of current diarrhea symptoms, assemblage B predominated with 89%, followed by assemblage A (8%) and mixed infection assemblage A and B (3%). We report a high prevalence of Giardia by PCR detection in Jimma, Ethiopia, with assemblage B being predominant. There was a similar distribution of Giardia assemblages between children with and without diarrhea. Increasing age was a risk factor for Giardia infection. Community-based prevention and control strategies need to be employed to decrease the risk of giardia infection.

Fish diversity and assemblage in the Batticaloa lagoon, Sri Lanka.

The Batticaloa Lagoon (Sri Lanka's third-largest brackish waterbody) has suffered habitat degradation and water quality deterioration during the past 30 years due to various anthropogenic activities. Despite Sri Lanka having 40 lagoons, inventories on the lagoon ichthyofauna are rather meagre and data on fish diversity and assemblages are scarce. An assessment of fish diversity is essential to maintain the ecological stability and lagoon fisheries. This study examined the fish fauna of the Batticaloa lagoon considering the northern and southern regions of the lagoon and various depths through a 3-year survey (2017-2019) and documented the dominant and rare fish species. In addition, biodiversity measures, species assemblages and the role of environmental parameters on the distribution of fishes were documented. Various diversity indices (the Margalef richness index, the Shannon-Weiner diversity index, Pielou's evenness index, the dominance index, the taxonomic diversity index, the average taxonomic distinctness index and the total taxonomic distinctness index) were calculated. Analysis of similarities (ANOSIM) was used to examine the seasonal and regional differences in the fish assemblages. The survey showed the occurrence of 96 species belonging to 40 families and 11 orders. Ambassis gymnocephalus was the most abundant fish species (8.7% of the total number of fishes collected) followed by Etroplus suratensis (6.8%), Arius maculatus (6.1%), Gerres filamentosus (5.3%), Oreochromis niloticus (4.6%) and Gerres abbreviates (3.9%). Dasyatis uarnak (0.02%), Acanthurus gahhm (0.03%), Alectis ciliaris (0.04%) and Crossorhombus valderostratus (0.08%) were considered as rare species which constitute less than 0.1% of the total while D. uarnak was considered a doubletons species (represented twice in the whole sample of 16 stations). Two types of species assemblages, one in the northern region and one in the southern region, were evident in a dendrogram (Based on the samples were collected on each region dendrogram were plotted with respect to sites then finally dendrogram of one region pratly connected by other region) based on sample composition similarity estimated with a Bray-Curtis matrix and nonmetric multidimensional scaling plots. The Bray-Curtis dissimilarity was 59.03% between the two regions, indicating statistically significant differences in assemblages (ANOSIM R 0.801; P < 0.01). The northern region of the lagoon had a higher number of species, density, Margalef richness, Pielou's evenness, Shannon-Wiener diversity, taxonomic diversity, taxonomic distinctness and total taxonomic distinctness compared to the southern region. The northern region showed significantly higher levels of salinity and dissolved oxygen (DO) and the southern region higher temperature, turbidity, phosphates and nitrates. The best subset of biota and environmental variables [BEST(BIO-ENV)] test showed a significant relationship between fish assemblage and environmental parameters. Distance-based linear model analysis showed a significant relationship between fish assemblage and the environmental parameters salinity, temperature, pH and DO. The sequential test of this analysis showed the environmental parameters to explain about 74.9% (R2 ) of the total variation. The bioenvironmental model developed was found to be appropriate. Thirteen species were found to be influential as they explained the overall fish distribution pattern with a Spearman rank correlation of 0.951. Ten groups of coherent species were also identified in the study area. In stations having anthropogenic activities, the fish diversity was low. The fish fauna of the Batticaloa lagoon should be monitored periodically to protect the fishery resources here. An understanding of the role that environment plays in structuring the fish assemblage in the Batticaloa lagoon and locations with critical habitats will be of great importance in the conservation and management of fishery resources in this lagoon. However, as monitoring only the dominant species may fail to pick up on important impacts affecting the less common species, it should be done using diversity indices and rare fish species. Monitoring is imperative in view of the livelihood of the fishers this lagoon supports and the health of the local people, as fish is a healthy food. The fishery resources of this lagoon must be protected for posterity with appropriate management measures.

Fish assemblage and guild structure in the Ashtamudi Estuary, a tropical Ramsar site in India.

A first hand study on guild structure of fish species (n = 148) in Ashtamudi Estuary, a Ramsar Site of International importance, was carried out from May 2019 to April 2020 based on temporal (monsoon, pre-monsoon and post-monsoon seasons) and spatial (upper, middle and lower zones) data. Guild composition consisted of eight estuarine use guilds (marine estuarine opportunist, marine estuarine dependent, estuarine resident species, anadromous species, freshwater migrants, freshwater stragglers, catadromous and marine stragglers) and eight feeding guilds (zooplanktivore, zoobenthivore, carnivores, herbivores, invertebrate feeders, omnivores, detritus feeders and piscivores). The most dominant estuarine use guilds comprised of marine migrants (marine estuarine opportunist and marine estuarine dependent), whereas carnivore, omnivore and zooplanktivore formed the dominant feeding guilds in Ashtamudi Estuary. The species diversity decreased from upper to lower zone and was highest during the post-monsoon period. The present study has seen a decrease in estuarine resident and freshwater species due to reduced freshwater inflow, saltwater intrusion, unsustainable fishing and inadequate environmental management practices. Hence, we propose a management framework to improve the ecosystem of Ashtamudi Estuary with a special focus on its fish species and their estuarine use.