
Shane Wallace GeangeNew Zealand Department of Conservation · Marine Ecosystems Team
Shane Wallace Geange
PhD, Victoria University of Wellington
About
70
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Introduction
Additional affiliations
September 2014 - September 2015
July 2013 - present
October 2010 - October 2013
Publications
Publications (70)
Many communities experience repeated periods of colonization due to seasonally regenerating habitats or pulsed arrival of young-of-year. When an individual's persistence in a community depends upon the strength of competitive interactions, changes in the timing of arrival relative to the arrival of a competitor can modify competitive strength and,...
How should ecologists and evolutionary biologists analyze nonnormal data that involve random effects? Nonnormal data such as counts or proportions often defy classical statistical procedures. Generalized linear mixed models (GLMMs) provide a more flexible approach for analyzing nonnormal data when random effects are present. The explosion of resear...
Most empirical studies of predation use simple experimental approaches to quantify the effects of predators on prey (e.g., using constant densities of predators, such as ambient vs. zero). However, predator densities vary in time, and these effects may not be well represented by studies that use constant predator densities. Although studies have in...
Management of Ecosystem Services (ES) in the marine environment requires consideration of the processes and biota involved in their production. Focusing attention at the scale of biogenic habitats can be a useful way forward: For numerous habitats and species their contributions to ecosystem functioning /ecosystem services can be determined from li...
Vulnerable Marine Ecosystems (VMEs) are recognised as having high ecological significance and susceptibility to disturbances, including climate change. One approach to providing information on the location and biological composition of these ecosystems, especially in difficult-to-reach environments such as the deep sea, is to generate spatial predi...
Regional Fisheries Management Organisations (RFMOs) use ‘move-on’ rules as one way to manage impacts to vulnerable marine ecosystems (VMEs). In response to a proposal to change the move-on distance from 1 to 5 nm for the South Pacific RFMO, we simulated trawl encounters using historical trawl data and information on the modelled size and spatial cl...
Vulnerable marine ecosystems (VMEs) are typically fragile and slow to recover, thereby making them susceptible to disturbance, including fishing. In the high seas, the United Nations General Assembly (UNGA) requested regional fishery management organisations (RFMOs) to implement measures to prevent significant adverse impacts on VMEs. Here, we pred...
The paper explores the frequency and the spatial distribution of interactions between midwater trawl targeting bentho-pelagic species on one side and Vulnerable Marine Ecosystem (VME) indicator taxa on another side from New Zealand flagged vessels in the SPRFMO Evaluated Area to inform any potential future improvements to the spatial management mea...
In the high seas, regional fishery management organisations are required to implement measures to prevent significant adverse impacts on vulnerable marine ecosystems (VMEs). Our objectives were to develop habitat suitability models for use in the spatial management of bottom fisheries in the South Pacific and to evaluate these and existing models u...
1. The New Zealand Seafloor Community Classification (NZSCC) is a national-scale numerical community classification which depicts compositional turnover of 1716 taxa (demersal fish, reef fish, benthic invertebrates and macroalgae) classified into 75 groups representing seafloor communities. To ensure the continual use of the NZSCC for spatial plann...
Although spatially explicit decision support tools are widely used in marine conservation planning, only a few studies have used multi-objective approaches to explicitly achieve biodiversity conservation and sustainable use objectives. Here, we use spatial analyses of a comprehensive environment-based classification (developed using Gradient Forest...
Vulnerable Marine Ecosystems (VMEs) are recognised as having high ecological significance and susceptibility to disturbances, including climate change. One approach to provide information about these ecosystems, especially in difficult-to-reach environments such as the deep sea, is to generate spatial predictions for VME indicator taxa. In this stu...
The waters around New Zealand are a global hotspot of biodiversity for deep-water corals; approximately one sixth of the known deep-water coral species of the world have been recorded in the region. Deep-water corals are vulnerable to climate-related stressors and from the damaging effects of commercial fisheries. Current protection measures do not...
The waters of Aotearoa New Zealand span over 4.2 million km2 of the South Pacific Ocean and harbour a rich diversity of seafloor-associated taxa. Due to the immensity and remoteness of the area, there are significant gaps in the availability of data that can be used to quantify and map the distribution of seafloor and demersal biodiversity, limitin...
The paper presents spatial predictions of density for 15 VME indicator taxa, based on a data-driven approach using observed abundance data (DTIS); and 4 VME indicator taxa, based on a principles-based approach using expert knowledge. It also presents spatial prediction of relative density for 1 VME indicator taxa based on the vector-autoregressive...
The paper introduces updated results to help identify broad-scale patterns of VME indicator taxa bycatch following the methodology presented by SC10-DW03, but with reference to the modified Bottom Trawl Management Areas (BTMAs) proposed by Australia and New Zealand in SC11-DW05 to protect a minimum of 70% suitable habitat for modelled VME indicator...
Marine habitats and ecosystems are under increasing pressure from human activities. Well-designed Marine Protected Area (MPA) networks can be highly effective tools for conserving biodiversity and associated ecosystem functions and services. Adequate coverage of biogeographic regions -i.e., large regions that represent broad-scale biodiversity patt...
The waters around New Zealand are a global hotspot of biodiversity for deep-water corals; approximately one sixth of the known deep-water coral species of the world have been recorded in the region. Deep-water corals are vulnerable to climate-related stressors and from the damaging effects of commercial fisheries. Current protection measures do not...
The waters of Aotearoa New Zealand span over 4.2 million km2 of the South Pacific Ocean and harbour a rich diversity of seafloor associated taxa. Due to the immensity and remoteness of the area, there are significant gaps in the availability of data to quantify and map the distribution of seafloor and demersal biodiversity, limiting effective manag...
Marine habitats and ecosystems are under increasing pressure from human activities. Well-designed Marine Protected Area (MPA) networks can be highly effective tools for conserving biodiversity and associated ecosystem functions and services. Adequate coverage of biogeographic regions – i.e., large regions that represent broad-scale biodiversity pat...
Although spatially explicit decision support tools are widely used in marine conservation planning, only a few studies have used multi-objective approaches to explicitly achieve biodiversity conservation and sustainable use objectives. Here, we use spatial analyses of a comprehensive environment-based classification that summarises spatial patterns...
Multibeam echosounder (MBES) surveys have become a standard tool for geophysical surveying and mapping of the seafloor. This technology helps us to develop consistent models for the study of seafloor features, understanding hydrodynamics, and studying marine life. Here, we used the tools provided within the current release of the Benthic Terrain Mo...
In order to support ongoing marine spatial planning in New Zealand, the Department of Conservation commissioned the National Institute of Water and Atmospheric Research (NIWA) to develop a suite of models to depict community composition of species known to live on or near the seabed across the country’s territorial sea and the Economic Exclusive Zo...
The Sea Change—Tai Timu Tai Pari Hauraki Gulf Marine Spatial Plan is New Zealand's first marine spatial plan and represents a collaborative response from mana whenua, local stakeholders, and regional and national governmental agencies to the threats and stressors responsible for the declining natural state of the Hauraki Gulf ecosystems. From a bio...
To support ongoing marine spatial planning in New Zealand, a numerical environmental classification using Gradient Forest models was developed using a broad suite of biotic and high-resolution environmental predictor variables. Gradient Forest modeling uses species distribution data to control the selection, weighting and transformation of environm...
Robust design of Marine Protected Areas in ocean environments is often challenging due to inadequate knowledge of biodiversity patterns, reflecting difficulties in the prediction of species distributions from sampling data that are often sparse or inadequate. Models that combine species and environmental data, such as Gradient Forests (GF), provide...
The United Nations General Assembly has called for the adoption of conservation management measures to protect vulnerable marine ecosystems (VMEs) from significant adverse impacts outside of areas of national jurisdiction. In response, many regional fisheries management organizations (RFMOs) have implemented move-on rules triggered by encounter thr...
Matrix approaches are useful for linking ecosystem services to habitats that underpin their delivery. Matrix applications in marine ecosystem services research have been primarily qualitative, focusing on 'habitat pre-sence' without including other attributes that effect service potential. We developed an evidence-based matrix approach of Ecosystem...
Aim
Producing quantitative descriptions of large‐scale biodiversity patterns is challenging, particularly where biological sampling is sparse or inadequate. This issue is particularly problematic in marine environments, where sampling is both difficult and expensive, often resulting in patchy and/or uneven coverage. Here, we evaluate the ability of...
• The projected changes in water T° and OA constitute major threats to ecosystem functioning, services and integrity, as they can affect key functional species, thus affecting their associated ecosystem processes (Berg et al. 2010). • Sponges are important members of Antarctic benthic communities (Cárdenas et al. 2016), potentially playing a centra...
This paper provides a characterisation of the catch of chondrichthyans in New Zealand bottom fisheries in the SPRFMO Area and information on potential risks to deepwater chondrichthyan species from SPRFMO bottom fishing. Chondrichthyans, particularly those which predominantly occur or complete most of their lifecycle below 200 m depth, are known to...
The Western Antarctic Peninsula is experiencing some of the most rapid climatic warming on the planet. The projected changes in water T° and OA constitute major threats to ecosystem functioning, services and integrity, as they can affect key functional species, thus affecting their associated ecosystem processes (Berg et al. 2010). Sponges are impo...
Several international agreements and conventions require nations to establish Marine Protected Area (MPA) networks as an approach to alleviating biodiversity declines; however, a common problem in planning MPA networks is how to balance conservation objectives against economic objectives. Here, using the distributions of 102 biodiversity features a...
(a) Dendrilla antarctica underneath Desmarestia spp. (10 m depth), Collins Bay, King George Island, Antarctica; (b) Haliclona (Gellius) sp. underneath Himantothallus grandifolius beds (15 m depth), South Bay, Doumer Island, Antarctica; (c) Scopalina sp. and Halisarca sp. growing on holfasts of Lessonia spp. (1 m depth), Punta Santa Ana, Magellan St...
Sponges are important components of high-latitude benthic communities, but their diversity and abundance in algal-dominated rocky reefs has been underestimated because of the difficulty of in situ identification. Further, the influence of canopy-forming algae on sponge richness has been poorly studied in southern high-latitude rocky reefs compared...
The sequence of species colonization is increasingly recognized as an important determinant of community structure, yet the significance of sequence of arrival relative to colonizer abundance is seldom assessed. We manipulated the magnitude and timing of coral-reef fish settlement to investigate whether the competitive dominance of early-arriving A...
Parasitism is hypothesized to reduce reproductive success in heavily parasitized males because females may preferentially mate with less parasitized males (parasite-mediated sexual selection) or parasites may compromise male competitiveness. In marine systems, this hypothesis is largely unexplored. This paper provides the first confirmed record of...
Although the frequency and magnitude of sedimentation often varies across coastal landscapes creating patches with different mean sediment loads, duration of sedimentation and rates of sediment resuspension, few studies have documented the emergent effects of spatio-temporal variability in sedimentation. Here, we conducted two laboratory experiment...
Macrocystis pyrifera (L.) C. Agardh provides biogenic habitat for species of significant commercial, cultural and recreational value; however, the floating surface canopies of M. pyrifera are particularly vulnerable to physical and biological disturbance (e.g., herbivory, storm events and harvesting). Given the key ecological roles of M. pyrifera,...
To facilitate predictions of howenvironmental heterogeneity affects invasion success and range expansion in the
kelp Undaria pinnatifida (Harvey) Suringar, it is essential to understand how physical and chemical dynamics influence
development and reproduction. Although the productivity of mature U. pinnatifida sporophytes is known
to be strongly in...
Marine organisms occasionally settle at exceptional densities, whereby thousands of individuals arrive concurrently. High levels of mortality, which has historically been attributed to predation or competition, often follow this epi- sodic settlement of reef fishes. Here, however, we observed large numbers of newly settled surgeonfish (Ctenochaetus...
High abundances of non-native species in the invaded range may be linked to changes in fitness related traits. However, few studies have compared differences in both life-history traits and abundances of introduced species between their native and invaded ranges. We determined differences in 12 morphological traits, an important fitness related tra...
Most empirical studies of predation use simple experimental approaches to quantify the effects of predators on prey (e.g., using constant densities of predators, such as ambient vs. zero). However, predator densities vary in time, and these effects may not be well represented by studies that use constant predator densities. Although studies have in...
Synthesis
Predation risk experienced by individuals living in groups depends on the balance between predator dilution, competition for refuges, and predator interference or synergy. These interactions operate between prey species as well: the benefits of group living decline in the presence of an alternative prey species. We apply a novel model-fit...
Interspecific competition is often asymmetric, and it can limit the spatial distributions of competitively inferior species within a community. When asymmetric competition involves 2 or more component species, the ranking of species' competitive abilities may form competitive hierarchies (all species of higher rank out-compete all species of lower...
Studies of predator foraging behavior typically focus on single prey species and fixed predator densities, ignoring the potential importance of complexities such as predator dilution; predator-mediated effects of alternative prey; heterospecific competition; or predator–predator interactions. Neglecting the effects of prey density is particularly p...
Species richness often peaks in the middle of bounded geographic domains (e.g. latitude, altitude or depth). Hump-shaped richness distributions may be due to deterministic processes, such as adaptations to environmental variation. Alternatively, such distributions might also be due to stochastic process. The mid-domain effect (MDE) posits that hump...
Although sea urchins play a central role in determining the structure and functioning of macroalgal communities in many parts of the world, past research in southern Chile has failed to identify strong effects of urchin grazing, despite the prevalence of coralline-dominated communities and abundant urchins, which indicate a likely structuring role...
Animals vary in their level of site fidelity and ability (or motivation) to return to a home site when displaced. Homing behaviour may be advantageous when the costs (e.g., associated with traversing a potentially hostile landscape) are outweighed by the collective benefits (e.g., access to resources and stable social interactions) of returning to...
1. Competition theory predicts that community structure may be shaped by resource partitioning between co-occurring species. As such, quantifying the degree of resource partitioning (i.e., niche overlap) is a key component of studies examining community structure and species coexistence.
2. For many organisms, multiple resource axes quantify niche...
The trophic ecology of cyanobacterial blooms is poorly understood on coral reefs. Blooms of toxic cyanobacteria, Lyngbya
majuscula, can quickly form large mats. The herbivorous sea hare, Stylocheilus striatus, and the predatory nudibranch, Gymnodoris ceylonica, often associate with these blooms, forming a linear food chain: nudibranch—sea hare—cyan...
Structural refuge and competition can influence the survival of coral reef fishes; however, the effect of structural refuge on the outcome of competition remains unclear. In Moorea, French Polynesia, surveys were used to quantify habitat association for juvenile Thalassoma hardwicke and 7 sympatric labroid species. Having identified the 3 species m...
Both habitat complexity and priority effects can influence the strength of competitive interactions; however, the independent and synergistic effects of these processes are not well understood. In Moorea, French Polynesia, we conducted a factorial field experiment to quantify the independent and combined effects of priority effects and habitat comp...
Both habitat complexity and competitive interactions can shape patterns of distribution and abundance of species. I evaluated the separate and joint effects of competitive interactions and habitat complexity on the survival of young fishes (Family Labridae) on coral reefs. First, I developed (in Chapter 2) a quantitative approach to evaluate potent...