George Branch

George Branch
University of Cape Town | UCT · Department of Biological Sciences

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276
Publications
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Publications

Publications (276)
Article
Diamond mining on the southern Namibian coastline has created multiple large coastal ponds of up to 380 000 m 2 adjacent to the coastline, as the sea overtops erected seawalls or seeps into excavated areas. These ponds span ages of 1-38 years. We investigated whether the ponds offer an environment for the establishment, growth and dispersal of salt...
Article
In a prequel to this paper, we used non-spatial temporal modelling to investigate the impact of non-native ecosystem engineers on a small-scale, intertidal rocky shore in Saldanha Bay, on the west coast of South Africa, where invasive species have changed the physical environment between 1980 and 2015. However, we considered this approach incomplet...
Data
Supplementary Table S1: NEOLI features, as defined by Edgar et al. (2014), showing how scoring was conducted for marine protected areas (MPAs) in the South African context. No-take = extent that regulations restrict fishing; Enforced = extent of compliance with regulations that restrict fishing, both through overt policing and through community sup...
Article
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We reviewed 140 papers to assess the ecological effectiveness of South Africa’s marine protected areas (MPAs). Evidence was assessed for coverage and representivity, protection of important biodiversity areas, other recognised elements of effectiveness, connectivity, and ecological effects—from the scale of individual MPAs to the MPA network scale....
Article
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Research on the socioeconomic aspects of marine protected areas (MPAs) in South Africa is reviewed to guide evaluation and integration. After a brief international review, we used declaration notices and management plans to determine the extent to which social and economic objectives have been included in the purpose statements of MPAs. We then rev...
Article
Between 1980 and 2012, successive arrivals by three alien ecosystem engineers on a rocky shore community at Marcus Island on the west coast of South Africa led to substantial changes in species composition and diversity. An ecosystem analysis of this open intertidal system was developed using Ecopath with Ecosim to determine the impacts of these al...
Article
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Worldwide, the spread of alien species in marine ecosystems has increased, with mussels frequently being involved. In South Africa, 91 alien and 39 cryptic marine and estuarine species, from 17 taxonomic groups, are known. Of these, three are associated with major invasions, including the Pacific mussel, Semimytilus algosus, which has rapidly sprea...
Article
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Global warming and ocean acidification influence marine calcifying organisms, particularly those with external shells. Among these, mussels may compensate for environmental changes by phenotypic plasticity, but this may entail trade-offs between shell deposition, growth and reproduction. We assessed main and interactive effects of pH and temperatur...
Chapter
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Tsitsikamma National Park on the southern coast of South Africa was proclaimed in 1964, making the marine part of the Park Africa's oldest marine protected area. In 2000 the entire marine area was designated as 'no-take' with extractive harvesting of resources prohibited. This conservation measure, which was aimed primarily at providing a refuge fo...
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Blender interstitial volume is a novel method that utilizes 3D modeling techniques to accurately and efficiently quantify the volume of interstitial gaps in marine benthic habitats, as well as the space provided by substrate rugosity. This method builds upon the analog methods routinely used on rocky shores and intertidal habitats, including those...
Article
Ecosystem engineers often affect structural complexity of habitats. There are multiple methods of quantifying complexity, variously measuring topography, surface area, volume, fractal dimension, or rugosity. We compared eight methods, four employing the 3D modelling program ‘Blender’ to estimate total surface area, top surface area, their ratio, an...
Article
Diet of the Tristan spiny lobster Jasus paulensis was examined using gut content and Stable Isotope Analyses (SIA) to assess whether diets differed among three islands in the Tristan da Cunha archipelago (Inaccessible, Nightingale and Tristan islands), and between small and large lobsters at two depth intervals. Gut fullness was significantly less...
Article
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The invasive mytilid mussel Semimytilus algosus was first recorded on South African shores in 2009 and rapidly spread to occupy 500 km of the West Coast, where it dominates lower portions of the rocky shore. To identify mechanisms underlying the invasive success of S. algosus, the life-history parameters survivorship, reproductive output, recruitme...
Article
The porcelain crab Porcellana africana Chace, 1956, a species native to NW Africa, between Western Sahara and Senegal, is reported from Saldanha Bay, South Africa, and both morphological evidence and DNA analysis are used to confirm its identity. The taxonomic history of P. africana is summarized, and the taxonomic implications of the DNA analysis...
Article
The South African coastline has been invaded by numerous alien species. Rare pre-invasion (1980) and post-invasion datasets (2001 and 2012) exist for Marcus Island, a small land-tied island in Saldanha Bay, South Africa. These snapshot datasets of the island’s intertidal invertebrate community were complemented with monitoring across seasons, from...
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s proxies and indicators of environmental conditions, offshore benthic assemblages are pertinent to understanding global change. To investigate long-term change in epibenthic assemblages, we compared digitally reprocessed historical (1988) and repeat (2013) benthic survey photographs from nearshore (40–130 m) and inter- island locations (140–500 m)...
Article
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Abiotic determinants of community composition on shallow reefs are seldom examined at a scale transcending biogeographic regions, and knowledge for the western Indian Ocean is sparse. To address this deficit, turnover in reef community composition was quantified, using gradient forest analyses, along gradients of nine abiotic variables collected in...
Article
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Stalked jellyfishes (Cnidaria: Staurozoa) are cryptic, benthic animals, known mainly from polar and temperate waters of the Northern Hemisphere. We describe a new species, Calvadosia lewisi, from South Africa and review the staurozoan fauna of the region. Three other species are previously known from South Africa: Calvadosia capensis (Carlgren, 193...
Article
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Distinctions are rarely made between vertical and horizontal surfaces when assessing reef community composition, yet physical differences are expected because of hydrodynamic differences and sediment accumulation on flat surfaces. As sand often diminishes biotic cover, we hypothesised that vertical surfaces will support a greater biomass but have l...
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Book Title: A Guide to, and Checklist for, the Decapoda of Namibia, South Africa and Mozambique Book Author: W.D. Emmerson 2016; Cambridge Scholars Publishing, Newcastle upon Tyne, United Kingdom Vol. 1: 590 pages, Vol. 2: 650 pages, Vol. 3: 720 pages; hard cover Vol. 1: ISBN 978-1-4438-9090-8, price £72.99 Vol. 2: ISBN 978-1-4438-9097-7, price £83...
Conference Paper
Full-text available
GİRİŞ İskenderun bölgesinden örneklenen Patella caerulea türünün DNA barkodlama yöntemi ile COI gen bölgesi kullanılarak tür seviyesinde tanımlama yapabildiği ve dünyadaki diğer örneklerle karşılaştırılarak tür içi genetik uzaklığının başarıyla hesaplanabildiği ortaya koyulmuştur. Filogenetik ağaçta Patella caerulea Türkiye örneğinin diğer Patella...
Article
Full-text available
Most sedentary marine animals disperse from their place of origin during their initial life stages as larvae. The delivery of planktonic larvae back to coastal adult habitats after weeks or months of offshore development is commonly thought to be stochastic, resulting in large recruitment fluctuations and making predictive understanding of populati...
Article
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The effects of collecting prawns (Callichirus and Upogebia spp.) in Langebaan Lagoon as bait were assessed in 1999–2001 and in 2012–2013. Langebaan Lagoon (part of West Coast National Park and a Marine Protected Area) is divided into three zones. One zone is a sanctuary, a second allows non-extractive visitation, and the third is for general use in...
Article
Full-text available
The effects of collecting prawns (Callichirus and Upogebia spp.) in Langebaan Lagoon as bait were assessed in 1999–2001 and in 2012–2013. Langebaan Lagoon (part of West Coast National Park and a Marine Protected Area) is divided into three zones. One zone is a sanctuary, a second allows non-extractive visitation, and the third is for general use in...
Article
Full-text available
In the Natal Bioregion of eastern South Africa, biomass of marine subtidal filter feeders is particularly high and makes a central contribution to distinguishing this bioregion from adjacent ones. We analysed the trophic role of riverine suspended particulate organic matter (POM) and the extent to which subsidies from rivers may explain this high f...
Article
The top-down effects of predators have been demonstrated for terrestrial, freshwater and marine systems and their removal can cause a shift in ecosystem state. In many cases, the depletion of top-predators occurred long before humans began monitoring these systems, but models can elucidate likely ecosystem changes. In this paper we use a multispeci...
Article
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The South African abalone Haliotis midae is a commercially valuable species, but its numbers are seriously depleted due to illegal fishing. Overfishing not only affects the targeted species, but also potentially influences the integrity and functioning of the ecosystem through associated changes in community composition. We assessed the herbivorous...
Article
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Effective conservation of the critically endangered hawksbill turtle (Eretmochelys imbricata) in the western Indian Ocean is hindered by a lack of basic ecological information about its diet and habitat requirements. This study utilised stomach samples from dead turtles and oesophageal lavage, together with in-water observations of foraging turtles...
Article
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Coastal ecosystems are highly vulnerable to human-mediated drivers of global change because they are located at the land-ocean interface and often host centres of urbanisation and development. The South African coastline comprises several distinct coastal ecoregions that support a wide range of coastal (inshore) ecosystems, including rocky, sandy a...
Article
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A survey of sandprawns and mudprawns was undertaken in intertidal and subtidal zones in Langebaan Lagoon, West Coast National Park, South Africa, to determine their stock status and to gain an understanding of the spatio-temporal patterns in abundance and distribution. Four species were recorded: Callichirus kraussi, C. rotundicaudata, Upogebia afr...
Article
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To resolve biogeographic limits and patterns on the east coast of Africa, the presence/absence and quantitative biomass data were collected from 55 shallow subtidal reefs along 4,800 km of coastline (5.2°–31.1°S). Multivariate analysis of distributions, trophic structure and biomass revealed two distinct marine provinces, the Tropical Indo-West Pac...
Article
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Algal blooms commonly occur along the South African west coast. In March 1994 a dense bloom developed within St Helena Bay. Its subsequent decay caused near-shore hypoxia and elevated hydrogen sulphide levels, leading to it being termed a ‘black tide’. The bloom caused immediate massive intertidal mortalities (95% reduction of biomass), significant...
Article
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This paper concerns the effects on biodiversity of depletion of the South African abalone Haliotis midae, which is a long-lived species with a large corrugated shell that provides a habitat for diverse benthic organisms. We compared community structure on H. midae shells with that on adjacent rock at three sites (Cape Point and Danger Point sites A...
Article
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The South African West Coast rock lobster, Jasus lalandii (H. Milne-Edwards, 1837), has expanded its range to the southeast, where its abundance has increased radically. The ecological consequences of this “invasion” are likely to be considerable. We employed a minimally realistic model to simulate the “invasion” and to explore interactions of J. l...
Article
Full-text available
The South African abalone Haliotis midae is commercially exploited and seriously threatened by overfishing. This not only affects the species itself but potentially the functioning of the ecosystem because of associated changes in community structure. The nature of effects that can follow the loss or reduction of a species depends in part on its po...
Article
Full-text available
Fish were surveyed by visual census on offshore reefs in Mozambique and eastern South Africa to compare (a) fully-protected ‘sanctuary’ areas, (b) ‘partly protected’ areas where recreational diving and limited fishing are permitted, and (c) ‘open’ unprotected areas. Community composition differed between coral-dominated reefs and those covered main...
Article
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Variability in larval settlement affects marine community dynamics at various spatial and temporal scales. To characterize settlement patterns and potential causes at different spatial scales, we monitored daily settlement rates of intertidal mussels and barnacles at two shore heights (mid, high) at a headland upwelling centre and in a downstream b...
Article
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An eastward shift in the center of abundance of the South African rock lobster Jasus lalandii occurred during the early 1990s into an area known as East of Cape Hangklip (EOCH). Given (1) the predatory capabilities of J. lalandii, (2) an intricate relationship between the urchin Parechinus angulosus and juveniles of the abalone Haliotis midae, and...
Article
Full-text available
November 2011 saw an unprecedented irruption of buoy barnacles Dosima fascicularis in coastal waters off the Western Cape, South Africa. Buoy barnacles not uncommonly strand in the region attached to feathers, plastic litter and other small objects, but the 2011 irruption saw exceptional numbers of unusually large colonies (average 23.5 individuals...
Article
Full-text available
Coastal ecosystems are highly vulnerable to human-mediated drivers of global change because they are located at the land–ocean interface and often host centres of urbanisation and development. The South African coastline comprises several distinct coastal ecoregions that support a wide range of coastal (inshore) ecosystems, including rocky, sandy a...
Article
Full-text available
Different processes shape ecological communities at different physical scales. Their relative importance is central to ecology, particularly in the case of foundational species like mussels. For 5 yr at 8 locations across 5 bioregions spanning 3200 km of the southern African coast, we monitored recruitment and adult populations of 4 intertidal muss...
Article
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Crustaceans classed as Thalassinidea are shrimp-like marine organisms that burrow predominantly in sediments. They have generated particular interest over the last decade because of their roles as ecosystem engineers that exert major influences over ecosystem processes and community structure. Their sphere of influence is wide as their burrowing ac...
Chapter
Crustaceans classed as Thalassinidea are shrimp-like marine organisms that burrow predominantly in sediments. They have generated particular interest over the last decade because of their roles as ecosystem engineers that exert major influences over ecosystem processes and community structure. Their sphere of influence is wide as their burrowing ac...
Article
Full-text available
During the 1990s the rock lobster Jasus lalandii shifted its focus of distribution south-eastwards along the coast of South Africa, to establish a dense population in an area where it was previously rare. This coincided with a marked decrease in the sea urchin Parechinus angulosus, a preferred prey item of J. lalandii and a vital source of shelter...
Article
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Field and laboratory experiments demonstrate that juveniles of South African abalone (Haliotis midae) depend vitally on the protection from predation that they gain from living concealed beneath Cape urchins (Parechinus angulosus). Recent reports suggest that rock lobsters (Jasus lalandii) have increased substantially in the region where the commer...
Article
Full-text available
Marine larval dispersal and recruitment dynamics are fundamentally linked with nearshore circulation. In coastal upwelling systems, shoreline topography induces predictable circulation patterns, spanning a range of spatial and temporal scales. Based on a 5 yr time series of monthly recruitment of intertidal mussels and barnacles at 8 sites along 40...
Data
The marine and coastal component of the National Biodiversity Assessment 2011 is an assessment of the state of biodiversity and ecosystems in South Africa’s marine and coastal environment. This report represents a milestone for marine biodiversity in South Africa. Major new contributions include the first national marine and coastal habitat classif...
Article
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Trends in the abundance, size and growth of newly settled pueruli and early juveniles of the rock lobster Jasus lalandii were determined from samples obtained from mesh bags used for oyster mariculture in Saldanha Bay, South Africa. Totals of 3 842 lobster pueruli and 10 158 juveniles were captured between August 2005 and June 2006, and distinct pu...
Article
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Settlement influences the distribution and abundance of many marine organisms, although the relative roles of abiotic and biotic factors influencing settlement are poorly understood. Species that aggregate often owe this characteristic to larval behaviour, and we investigated whether this predisposes ascidians to becoming invasive, by increasing th...
Data
a b s t r a c t Ecosystem engineering by plants and animals significantly influences community structure and the physico-chemical characteristics of marine habitats. In this paper we document the contrasting effects of ecosystem engineering by the cordgrass Spartina maritima and the burrowing sandprawn Callianassa kraussi on physico-chemical charac...
Article
Full-text available
The rock lobster Jasus lalandii expanded its centre of distribution south-eastwards into an area known as ‘East of Cape Hangklip’ on the south-west coast of South Africa in the early 1990s. Using historical and present data, we analysed differences in the abundance of key species and functional groups between the pre- and post-rock lobster invasion...
Article
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Quantifying sessile marine invertebrate recruitment often requires destructive sampling or extrapolation from artificial substrata, the latter introducing the danger of artifacts. We measured intertidal mussel recruitment into mussel beds and into brushes at three-month intervals for fiveyears across 3,200km of southern Africa and determined substr...