Reviewing evidence of marine ecosystem change off South Africa

Clearance of terrestrial wetland vegetation and rainfall variations affect biodiversity. The rainfall trend–NDVI (Normalized Difference Vegetation Index) relationship was examined to assess the extent to which rainfall affects vegetation productivity within Nylsvley, Ramsar site in Limpopo Province, South Africa. Daily rainfall data measured from eight rainfall stations between 1950 and 2016 were used to generate seasonal and annual rainfall data. Mann-Kendall and quantile regression were applied to assess trends in rainfall data. NDVI was derived from satellite images from between 1984 and 2003 using Zonal statistics and correlated with rainfall of the same period to assess vegetation dynamics. Mann-Kendall and Sen’s slope estimator showed only one station had a significant increasing rainfall trend annually and seasonally at p < 0.05, whereas all the other stations showed insignificant trends in both rainfall seasons. Quantile regression showed 50% and 62.5% of the stations had increasing annual and seasonal rainfall, respectively. Of the stations, 37.5% were statistically significant at p < 0.05, indicating increasing and decreasing rainfall trends. These rainfall trends show that the rainfall of Nylsvley decreased between 1995 and 2003. The R2 between rainfall and NDVI of Nylsvley is 55% indicating the influence of rainfall variability on vegetation productivity. The results underscore the impact of decadal rainfall patterns on wetland ecosystem change.

Download Full-text

Relating marine ecosystem indicators to fishing and environmental drivers: an elucidation of contrasting responses

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp258 ◽

2009 ◽

Vol 67 (4) ◽

pp. 787-795 ◽

Cited By ~ 82

Author(s):

Jason S. Link ◽

Dawit Yemane ◽

Lynne J. Shannon ◽

Marta Coll ◽

Yunne-Jai Shin ◽

...

Keyword(s):

Marine Ecosystem ◽

Ecosystem Dynamics ◽

Environmental Drivers ◽

Ecosystem Change ◽

Relative Importance ◽

Ecosystem Sensitivity ◽

Ecosystem Indicators ◽

Proxy Indicators ◽

Key Drivers ◽

Ecosystem Drivers

Abstract Link, J. S., Yemane, D., Shannon, L. J., Coll, M., Shin, Y-J., Hill, L., and Borges, M. F. 2010. Relating marine ecosystem indicators to fishing and environmental drivers: an elucidation of contrasting responses. – ICES Journal of Marine Science, 67: 787–795. The usefulness of indicators in detecting ecosystem change depends on three main criteria: the availability of data to estimate the indicator (measurability), the ability to detect change in an ecosystem (sensitivity), and the ability to link the said change in an indicator as a response to a known intervention or pressure (specificity). Here, we specifically examine the third aspect of indicator change, with an emphasis on multiple methods to explore the “relativity” of major ecosystem drivers. We use a suite of multivariate methods to explore the relationships between a pre-established set of fisheries-orientated ecosystem status indicators and the key drivers for those ecosystems (particularly emphasizing proxy indicators for fishing and the environment). The results show the relative importance among fishing and environmental factors, which differed notably across the major types of ecosystems. Yet, they also demonstrated common patterns in which most ecosystems, and indicators of ecosystem dynamics are largely driven by fisheries (landings) or human (human development index) factors, and secondarily by environmental drivers (e.g. AMO, PDO, SST). How one might utilize this empirical evidence in future efforts for ecosystem approaches to fisheries is discussed, highlighting the need to manage fisheries in the context of environmental and other human (e.g. economic) drivers.

Download Full-text

Biodiversity Monitoring in Mediterranean Marine Protected Areas: Scientific and Methodological Challenges

Diversity ◽

10.3390/d14010043 ◽

2022 ◽

Vol 14 (1) ◽

pp. 43

Author(s):

Carlo Nike Bianchi ◽

Annalisa Azzola ◽

Silvia Cocito ◽

Carla Morri ◽

Alice Oprandi ◽

...

Keyword(s):

Protected Areas ◽

Marine Protected Areas ◽

Natural Capital ◽

Human Impacts ◽

Marine Ecosystem ◽

Spatial Modelling ◽

Habitat Diversity ◽

Ecosystem Change ◽

Environmental Status ◽

Genes To Ecosystems

Biodiversity is a portmanteau word to indicate the variety of life at all levels from genes to ecosystems, but it is often simplistically equated to species richness; the word ecodiversity has thus been coined to address habitat variety. Biodiversity represents the core of the natural capital, and as such needs to be quantified and followed over time. Marine Protected Areas (MPAs) are a major tool for biodiversity conservation at sea. Monitoring of both species and habitat diversity in MPAs is therefore mandatory and must include both inventory and periodic surveillance activities. In the case of inventories, the ideal would be to census all species and all habitats, but while the latter goal can be within reach, the former seems unattainable. Species inventory should be commeasured to investigation effort, while habitat inventory should be based on mapping. Both inventories may profit from suitability spatial modelling. Periodic surveillance actions should privilege conspicuous species and priority habitats. Efficient descriptor taxa and ecological indices are recommended to evaluate environmental status. While it seems obvious that surveillance activities should be carried out with regular recurrence, diachronic inventories and mapping are rarely carried out. Time series are of prime importance to detect marine ecosystem change even in the absence of direct human impacts.

Download Full-text

Use of sensitivity and comparative analyses in constructing plausible trophic mass-balance models of a data-limited marine ecosystem — The KwaZulu-Natal Bight, South Africa

Journal of Marine Systems ◽

10.1016/j.jmarsys.2011.05.006 ◽

2011 ◽

Vol 88 (2) ◽

pp. 298-311 ◽

Cited By ~ 21

Author(s):

Morag J. Ayers ◽

Ursula M. Scharler

Keyword(s):

South Africa ◽

Mass Balance ◽

Marine Ecosystem ◽

Comparative Analyses ◽

Mass Balance Models ◽

Kwazulu Natal

Download Full-text

Ecosystem change during MIS 4 and early MIS 3: Evidence from Middle Stone Age sites in South Africa

African Palaeoenvironments and Geomorphic Landscape Evolution ◽

10.1201/b10542-10 ◽

2010 ◽

pp. 105-132

Keyword(s):

South Africa ◽

Middle Stone Age ◽

Ecosystem Change ◽

Stone Age ◽

Mis 3

Download Full-text

Large-scale marine ecosystem change and the conservation of marine mammals

Journal of Mammalogy ◽

10.1644/07-mamm-s-416r.1 ◽

2008 ◽

Vol 89 (3) ◽

pp. 529-533 ◽

Cited By ~ 13

Author(s):

Thomas J. O'Shea ◽

Daniel K. Odell

Keyword(s):

Marine Mammals ◽

Large Scale ◽

Marine Ecosystem ◽

Ecosystem Change

Download Full-text

Different triggers for the two pulses of mass extinction across the Permian and Triassic boundary

Scientific Reports ◽

10.1038/s41598-021-86111-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Guoshan Li ◽

Wei Liao ◽

Sheng Li ◽

Yongbiao Wang ◽

Zhongping Lai

Keyword(s):

Mass Extinction ◽

Temporal Dynamics ◽

Oxygen Deficiency ◽

Marine Ecosystem ◽

Volcanic Eruptions ◽

Ecosystem Change ◽

Triassic Boundary ◽

Low Diversity ◽

Micritic Limestone ◽

Fossil Records

AbstractWidespread ocean anoxia has been proposed to cause biotic mass extinction across the Permian–Triassic (P–Tr) boundary. However, its temporal dynamics during this crisis period are unclear. The Liangfengya section in the South China Block contains continuous marine sedimentary and fossil records. Two pulses of biotic extinction and two mass extinction horizons (MEH 1 & 2) near the P–Tr boundary were identified and defined based on lithology and fossils from the section. The data showed that the two pulses of extinction have different environmental triggers. The first pulse occurred during the latest Permian, characterized by disappearance of algae, large foraminifers, and fusulinids. Approaching the MEH 1, multiple layers of volcanic clay and yellowish micritic limestone occurred, suggesting intense volcanic eruptions and terrigenous influx. The second pulse occurred in the earliest Triassic, characterized by opportunist-dominated communities of low diversity and high abundance, and resulted in a structural marine ecosystem change. The oxygen deficiency inferred by pyrite framboid data is associated with biotic declines above the MEH 2, suggesting that the anoxia plays an important role.

Download Full-text

Occurrence of the Freshwater Chrysophyte Poterioochromonas malhamensis in a High Arctic Marine Ecosystem

Water ◽

10.3390/w13152129 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2129

Author(s):

Fang Zhang ◽

Yongjun Tian ◽

Jianfeng He

Keyword(s):

Dominant Species ◽

Marine Ecosystem ◽

High Arctic ◽

Water Masses ◽

Epifluorescence Microscopy ◽

Ecosystem Change ◽

Eukaryotic Community ◽

Arctic Fjord ◽

Community Variability ◽

Poterioochromonas Malhamensis

Kongsfjorden is a small Arctic fjord but with great hydrographic complexity and has changed greatly due to the climate change. Arctic warming has increased melts of sea ice and glaciers that results in higher freshwater content. Microbial community variability and increasing terrestrial input were detected continuously in recent years ITag eukaryotic 18S rRNA V4 metabarcoding, photosynthetic pigments analysis and epifluorescence microscopy were used to reveal the dominant species of small eukaryotic community (<20 μm). Both Spearman correlation and redundant analysis were used to study the correlation between the small eukaryotes and the environmental conditions. In the present study, the surface water with salinity lower than 34 was thicker than in summers of previous years. The freshwater mixotrophic chrysophyte Poterioochromonas malhamensis was found for the first time as the dominant species. No general trends were found for the contributions of P. malhamensis to the total reads of small eukaryotes in water depths; and no obvious differences were found at different stations and water masses. Phagotrophy, which is more common than phototrophy at all times in P. malhamensis, is thought to be the main reason for the prevalence of P. malhamensis in Kongsfjorden. The occurrence of P. malhamensis induced a disorder in the small eukaryotic community, which biodiversity and composition showed weak correlation with the water masses. The dominance of the freshwater-originating phytoplankton may indicate an ecosystem change in the Kongsjforden, which probably might become more remarkable in the future as the climate continues to change.

Download Full-text

Capelin (Mallotus villosus) distribution and climate: a sea “canary” for marine ecosystem change

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.05.008 ◽

2005 ◽

Vol 62 (7) ◽

pp. 1524-1530 ◽

Cited By ~ 82

Author(s):

G.A. Rose

Keyword(s):

Temperature Change ◽

North Atlantic ◽

Marine Ecosystem ◽

Predatory Fish ◽

Ecosystem Change ◽

Monitoring Methods ◽

Mallotus Villosus ◽

The North ◽

Capelin Mallotus Villosus ◽

The North Atlantic

Abstract Capelin (Mallotus villosus) is a classic “r” adapted pelagic species that inhabits the northern boreal oceans at the margins of cold Arctic waters. The species originated in the North Pacific and colonized the North Atlantic at least once during interglacial periods of the past few million years. Capelin became the main forage species for many larger predatory fish, and also for seabirds and marine mammals. The colonizing abilities of capelin have been noted in historical anecdotes, typically in concert with climate variations. In this paper, all known shifts in distribution are catalogued. Shifts have taken place at the larval and adult stages, and some result in new spawning locations, others do not. Displacement distance relates to temperature change: log10(distancekm) = 0.28 × temperature change + 2.16 (p < 0.05, r2 = 0.91). The persistence of the shifts relates to the displacement distance: log10(persistencey) = 2.62 × log10(distancekm) − 6.56 (p < 0.05, r2 = 0.83). The quick and consistent response of capelin to temperature change, its importance to the North Atlantic foodweb, and established monitoring methods suggest this species as a sea “canary” for northern boreal marine ecosystem responses to climate variability and change.

Download Full-text

Marine conservation in the republic of South Africa with special reference to marine parks and reserves

Koedoe ◽

10.4102/koedoe.v20i2.1289 ◽

1977 ◽

Vol 20 (2) ◽

Author(s):

G.A. Robinson

Keyword(s):

South Africa ◽

Adverse Effects ◽

Special Reference ◽

Marine Environment ◽

Marine Ecosystem ◽

Marine Conservation ◽

Habitat Destruction ◽

The Republic

Conservation in the Republic of South Africa (RSA) is dominated by big game and terrestrial reserves. Protecting these, have been in existence for many years. Recently Man has turned his attention more and more to the sea and due to adverse effects of pollution, overexploitation and habitat destruction the marine environment is threatened. However, conservationists have learnt lessons about both terrestrial and marine ecosystem-destruction and are now demanding with increasing persistence the establishment of marine parks and reserves.

Download Full-text