scholarly journals Linking habitat mosaics and connectivity in a coral reef seascape

2012 ◽  
Vol 109 (38) ◽  
pp. 15372-15376 ◽  
Author(s):  
Kelton W. McMahon ◽  
Michael L. Berumen ◽  
Simon R. Thorrold

Tropical marine ecosystems are under mounting anthropogenic pressure from overfishing and habitat destruction, leading to declines in their structure and function on a global scale. Although maintaining connectivity among habitats within a seascape is necessary for preserving population resistance and resilience, quantifying movements of individuals within seascapes remains challenging. Traditional methods of identifying and valuing potential coral reef fish nursery habitats are indirect, often relying on visual surveys of abundance and correlations of size and biomass among habitats. We used compound-specific stable isotope analyses to determine movement patterns of commercially important fish populations within a coral reef seascape. This approach allowed us to quantify the relative contributions of individuals from inshore nurseries to reef populations and identify migration corridors among important habitats. Our results provided direct measurements of remarkable migrations by juvenile snapper of over 30 km, between nurseries and reefs. We also found significant plasticity in juvenile nursery residency. Although a majority of individuals on coastal reefs had used seagrass nurseries as juveniles, many adults on oceanic reefs had settled directly into reef habitats. Moreover, seascape configuration played a critical but heretofore unrecognized role in determining connectivity among habitats. Finally, our approach provides key quantitative data necessary to estimate the value of distinctive habitats to ecosystem services provided by seascapes.

2024 ◽  
Vol 74 (10) ◽  
pp. 6139-2024
Author(s):  
MICHAŁ SCHULZ ◽  
ALEKSANDRA ŁOŚ ◽  
PATRYCJA SKOWRONEK ◽  
ANETA STRACHECKA

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.


2020 ◽  
Vol 71 (1) ◽  
pp. 149-161 ◽  
Author(s):  
Ilias Attaye ◽  
Sara-Joan Pinto-Sietsma ◽  
Hilde Herrema ◽  
Max Nieuwdorp

Cardiometabolic disease (CMD), such as type 2 diabetes mellitus and cardiovascular disease, contributes significantly to morbidity and mortality on a global scale. The gut microbiota has emerged as a potential target to beneficially modulate CMD risk, possibly via dietary interventions. Dietary interventions have been shown to considerably alter gut microbiota composition and function. Moreover, several diet-derived microbial metabolites are able to modulate human metabolism and thereby alter CMD risk. Dietary interventions that affect gut microbiota composition and function are therefore a promising, novel, and cost-efficient method to reduce CMD risk. Studies suggest that fermentable carbohydrates can beneficially alter gut microbiota composition and function, whereas high animal protein and high fat intake negatively impact gut microbiota function and composition. This review focuses on the role of macronutrients (i.e., carbohydrate, protein, and fat) and dietary patterns (e.g., vegetarian/vegan and Mediterranean diet) in gut microbiota composition and function in the context of CMD.


2021 ◽  
Vol 14 ◽  
pp. 194008292110281
Author(s):  
Faith Thomas Mpondo ◽  
Patrick A. Ndakidemi ◽  
Anna C. Treydte

Insect pollinators provide numerous ecosystem services that support other living organisms. While pollinators play a large role in cropping systems, little is known about their presence and function in rangeland ecosystems, which have recently become fragmented and overexploited at an extraordinary rate. We assessed local Maasai knowledge on insect pollinators and how pollinators affect livelihood diversification in Simanjiro rangelands, Tanzania. Through questionnaires, key informant interviews, focus group discussions, and field observations, we found varied insect knowledge among Maasai herders. Lasioglossum of sub genus Ipomalictus and Syriphidae were the least commonly recognized pollinators as only 24%, and 7% of participants could identify them, respectively. Responses varied significantly between men and women (F = 7.397, p = .007). Commiphora africana, Acacia mellifera and Albizia anthelmintica were noted as most important bee forage plants while observations showed Aspilia mossambicensis, Justicia debile and Acacia tortilis. Most (77%) of Maasai herders showed limited ability to link pollinators and rangeland wellbeing. Beekeeping contributed to livelihood diversification for 61% of respondents, with women participating more frequently than men (χ2 = 46.962, p = .0001). Beekeeping was positively influenced by education level ( R = .421, p < .0001) and occupation ( R = .194, p = .009). Pollinator declines were attributed to climate change (47%), agriculture (37%), and habitat destruction (8%). We conclude that Maasai have limited knowledge of common pollinator groups and their roles. Community outreach and training should bridge the knowledge gap in pastoralist communities to fully realize pollinator benefits and highlight the importance of rangeland health.


2015 ◽  
Vol 12 (5) ◽  
pp. 1339-1356 ◽  
Author(s):  
N. S. Jones ◽  
A. Ridgwell ◽  
E. J. Hendy

Abstract. Calcification by coral reef communities is estimated to account for half of all carbonate produced in shallow water environments and more than 25% of the total carbonate buried in marine sediments globally. Production of calcium carbonate by coral reefs is therefore an important component of the global carbon cycle; it is also threatened by future global warming and other global change pressures. Numerical models of reefal carbonate production are needed for understanding how carbonate deposition responds to environmental conditions including atmospheric CO2 concentrations in the past and into the future. However, before any projections can be made, the basic test is to establish model skill in recreating present-day calcification rates. Here we evaluate four published model descriptions of reef carbonate production in terms of their predictive power, at both local and global scales. We also compile available global data on reef calcification to produce an independent observation-based data set for the model evaluation of carbonate budget outputs. The four calcification models are based on functions sensitive to combinations of light availability, aragonite saturation (Ωa) and temperature and were implemented within a specifically developed global framework, the Global Reef Accretion Model (GRAM). No model was able to reproduce independent rate estimates of whole-reef calcification, and the output from the temperature-only based approach was the only model to significantly correlate with coral-calcification rate observations. The absence of any predictive power for whole reef systems, even when consistent at the scale of individual corals, points to the overriding importance of coral cover estimates in the calculations. Our work highlights the need for an ecosystem modelling approach, accounting for population dynamics in terms of mortality and recruitment and hence calcifier abundance, in estimating global reef carbonate budgets. In addition, validation of reef carbonate budgets is severely hampered by limited and inconsistent methodology in reef-scale observations.


mBio ◽  
2021 ◽  
Author(s):  
J. Goordial ◽  
T. D’Angelo ◽  
J. M. Labonté ◽  
N. J. Poulton ◽  
J. M. Brown ◽  
...  

The subsurface rock beneath the ocean is one of the largest biospheres on Earth, and microorganisms within influence global-scale nutrient cycles. This biosphere is difficult to study, in part due to the low concentrations of microorganisms that inhabit the vast volume of the marine lithosphere.


2014 ◽  
Vol 37 (1) ◽  
pp. 69-72
Author(s):  
Giriraj Panwar ◽  
Kumar Ambrish ◽  
S. Srivastava

Indopiptadenia oudhensis (Brandis) Brenan is an endangered tree species of family Mimosaceae. Species is mainly distributed at Indo-Nepal border and facing threats such as anthropogenic pressure, habitat destruction, over exploitation, low seed viability and poor seed germination.


2020 ◽  
Vol 6 (40) ◽  
pp. eabb1046
Author(s):  
Jonathan D. Cybulski ◽  
Stefan M. Husa ◽  
Nicolas N. Duprey ◽  
Briony L. Mamo ◽  
Toby P. N. Tsang ◽  
...  

Observations of coral reef losses to climate change far exceed our understanding of historical degradation before anthropogenic warming. This is a critical gap to fill as conservation efforts simultaneously work to reverse climate change while restoring coral reef diversity and function. Here, we focused on southern China’s Greater Bay Area, where coral communities persist despite centuries of coral mining, fishing, dredging, development, and pollution. We compared subfossil assemblages with modern-day communities and revealed a 40% decrease in generic diversity, concomitant to a shift from competitive to stress-tolerant species dominance since the mid-Holocene. Regions with characteristically poor water quality—high chl-a, dissolved inorganic nitrogen, and turbidity—had lower contemporary diversity and the greatest community composition shift observed in the past, driven by the near extirpation of Acropora. These observations highlight the urgent need to mitigate local stressors from development in concert with curbing greenhouse gas emissions.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xinyue Zhang ◽  
Bo Ma ◽  
Jiawen Liu ◽  
Xiehui Chen ◽  
Shanshan Li ◽  
...  

Abstract Background Cellulose degradation by cellulase is brought about by complex communities of interacting microorganisms, which significantly contribute to the cycling of carbon on a global scale. β-Glucosidase (BGL) is the rate-limiting enzyme in the cellulose degradation process. Thus, analyzing the expression of genes involved in cellulose degradation and regulation of BGL gene expression during composting will improve the understanding of the cellulose degradation mechanism. Based on our previous research, we hypothesized that BGL-producing microbial communities differentially regulate the expression of glucose-tolerant BGL and non-glucose-tolerant BGL to adapt to the changes in cellulose degradation conditions. Results To confirm this hypothesis, the structure and function of functional microbial communities involved in cellulose degradation were investigated by metatranscriptomics and a DNA library search of the GH1 family of BGLs involved in natural and inoculated composting. Under normal conditions, the group of non-glucose-tolerant BGL genes exhibited higher sensitivity to regulation than the glucose-tolerant BGL genes, which was suppressed during the composting process. Compared with the expression of endoglucanase and exoglucanase, the functional microbial communities exhibited a different transcriptional regulation of BGL genes during the cooling phase of natural composting. BGL-producing microbial communities upregulated the expression of glucose-tolerant BGL under carbon catabolite repression due to the increased glucose concentration, whereas the expression of non-glucose-tolerant BGL was suppressed. Conclusion Our results support the hypothesis that the functional microbial communities use multiple strategies of varying effectiveness to regulate the expression of BGL genes to facilitate adaptation to environmental changes.


2010 ◽  
Vol 61 (6) ◽  
pp. 1505-1514 ◽  
Author(s):  
A. Vaghela ◽  
P. Bhadja ◽  
J. Ramoliya ◽  
N. Patel ◽  
R. Kundu

Present communication reports the physico-chemical and biological quality of seawater and status of benthos of a highly industrialized shore of the north-western coastline of India. The coastal area considered for the present study, encircled by a variety of industries, was divided into two sampling sites and monitored for two consecutive years. Results of the water quality suggest that the obtained values of the physical and chemical parameters of seawater were comparable with data reported earlier. However, data obtained in the biological parameters of the seawater showed a declining trend. Results of the intertidal macrofaunal diversity studies revealed that the muddy upper littoral zones were represented by few species of coelenterata, porifera, arthropoda and mollusca. In the rocky—muddy middle littoral zones, gastropods, stars fishes, corallites, crabs, polychetes and tubeworms were present, whereas, predominantly rocky lower littoral zones were comparatively rich in macrofaunal diversity with small patches of coral colonies. However, when the results obtained in the present study was compared with that of earlier reported data, it was clear that the macrofaunal diversity indeed declined considerably over the years. This may be due to habitat destruction and habitat alteration in the coastline caused by increased anthropogenic activities in the area. Seasonal variations in the population density and abundance were observed in most of the faunal groups except in sessile corals and sponges. This may be due to local migration of the faunal groups towards deeper regions of the Gulf, as supported by the analysis of similarity, to avoid influx of freshwater during monsoon, and high temperature during summer and post monsoon seasons. The overall assessment of different parameters of this study revealed that though the physico- chemical characteristics of the seawater did not varied much from the earlier reported status, the biological characteristics of the seawater and intertidal zone was affected possibly by a high degree of anthropogenic pressure.


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