Dredging fundamentally reshapes the ecological significance of 3D terrain features for fish in estuarine seascapes     

Borland  Hayden P.  Gilby  Ben L.  Henderson  Christopher J.  Connolly  Rod M.  Gorissen  Bob  Ortodossi  Nicholas L.  Rummell  Ashley J.  Pittman  Simon J.  Sheaves  Marcus  Olds  Andrew D. 《Landscape Ecology》2022,37(5):1385-1400

Landscape Ecology - Landscape modification alters the condition of ecosystems and the structure of terrain, with widespread impacts on biodiversity and ecosystem functioning. Seafloor dredging...  相似文献   

Variations in condition and body constitution in a tropical estuarine fish with year-round recruitment     

Molony  Brett W.  Sheaves  Marcus J. 《Mangroves and Salt Marshes》1998,2(3):177-185

Fish condition (Fulton's K) and the abundance of biochemical constituents (water, protein, lipid and carbohydrate) of juveniles of the tropical estuarine fish, Ambassis vachelli, were monitored over a 15 month period. Fulton's K and biochemical constituents of juveniles recruiting into the adult habitat varied significantly throughout the study. Correlations between Fulton's K and all biochemical measures were weak, with a maximum correlation of 0.1379 (with protein abundance). Significant differences in condition and body constitution of individuals suggest that juveniles recruiting into the adult habitat are not in equal condition and therefore survivorship and success may vary within and among cohorts. Temperature (and salinity) display greater variation in tropical estuarine waters than in other tropical waters and are likely to play a role in determining recruit condition and body constitution. However, the exact role of physical parameters in determining condition and body constitution of fishes is still unknown.  相似文献   

Sportfisheries,conservation and sustainable livelihoods: a multidisciplinary guide to developing best practice          下载免费PDF全文

Adam Barnett  Kátya G Abrantes  Ronald Baker  Amy S Diedrich  Marina Farr  Alf Kuilboer  Tracey Mahony  Ian McLeod  Gianna Moscardo  Murray Prideaux  Natalie Stoeckl  Ariella van Luyn  Marcus Sheaves 《Fish and Fisheries》2016,17(3):696-713

Ecotourism ventures in developing countries are often among the few alternatives for enhancing sustainable livelihoods without altering traditional ways of life. The best way forward is to continually develop and implement best practice guidelines and, in particular, to flexibly develop them to suit individual cases. We conduct a multidisciplinary assessment of best practice guidelines required to develop and sustain sportfishing tourism in developing countries, while enhancing local livelihoods and promoting environmental stewardship. In general, best practice guidelines should be developed around a sustainable livelihood framework that includes short‐term coping mechanisms and longer‐term capacity building. Sportfishing development that conforms to ecological and socially orientated criteria, founded on site‐specific research that captures local environmental and social complexities, has the potential to provide mutual benefits to tourists and local people, fuelling community development and enhancing the cultural experience of tourists. Best practice guidelines for sportfishing that do not address these dimensions are unlikely to result in a viable industry. Given the current interest and growth of sportfishing in developing countries, the proposed guidelines can help a range of end users manage, conserve and maximize livelihood benefits from their fishery.  相似文献   

The consequences of paradigm change and poorly validated science: The example of the value of mangroves to fisheries     

Marcus Sheaves  Ktya Abrantes  Adam Barnett  Claudia Benham  Patricia Dale  Carlo Mattone  Alison Sheaves  Nathan Waltham  Michael Bradley 《Fish and Fisheries》2020,21(5):1067-1075

Accuracy in representing, communicating and reporting science is critical to the translation of science into knowledge. Any lack of accuracy degrades the quality and reliability of consequent decisions. One common cause of inaccuracy is the use of superseded paradigmatic concepts with a lack of careful validation. This leads to evidentiary dissonance (an apparent abundance of evidence with little basis in actual reported scientific findings). We illustrate the nature and consequences of evidentiary dissonance using the example of estimates of the value of mangroves to fisheries, which are key motivators of decision‐making around land‐use activities in mangroves systems, mangrove restoration and disturbance offset initiatives. Causes include the use of inappropriate or inaccurate data and inadequate support for reasoning used to develop estimates of fisheries value. Evidentiary dissonance in linking estimates to scientific understanding has produced a citable and cited body of work with tenuous foundations in current ecological understanding, and a body of literature that is likely to lead to unrealistic expectations, misdirected and wasted resources, and perverse management outcomes.  相似文献   

Spatial dynamics of coastal forest bird assemblages: the influence of landscape context,forest type,and structural connectivity     

Christina A. Buelow  Ronald Baker  April E. Reside  Marcus Sheaves 《Landscape Ecology》2017,32(3):547-561

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The seascape nursery: a novel spatial approach to identify and manage nurseries for coastal marine fauna          下载免费PDF全文

Ivan Nagelkerken  Marcus Sheaves  Ronald Baker  Rod M Connolly 《Fish and Fisheries》2015,16(2):362-371

Coastal marine and estuarine ecosystems are highly productive and serve a nursery function for important fisheries species. They also suffer some of the highest rates of degradation from human impacts of any ecosystems. Identifying and valuing nursery habitats is a critical part of their conservation, but current assessment practices typically take a static approach by considering habitats as individual and homogeneous entities. Here, we review current definitions of nursery habitat and propose a novel approach for assigning nursery areas for mobile fauna that incorporates critical ecological habitat linkages. We introduce the term ‘seascape nurseries’, which conceptualizes a nursery as a spatially explicit seascape consisting of multiple mosaics of habitat patches that are functionally connected. Hotspots of animal abundances/productivity identify the core area of a habitat mosaic, which is spatially constrained by the home ranges of its occupants. Migration pathways connecting such hotspots at larger spatial and temporal scales, through ontogenetic habitat shifts or inshore–offshore migrations, should be identified and incorporated. The proposed approach provides a realistic step forward in the identification and management of critical coastal areas, especially in situations where large habitat units or entire water bodies cannot be protected as a whole due to socio‐economic, practical or other considerations.  相似文献   

Identification of essential habitats: Including chimaeras into current shark protected areas     

Adam Barnett  Jamie D. McAllister  Jayson Semmens  Ktya Abrantes  Marcus Sheaves  Cynthia Awruch 《水产资源保护:海洋与淡水生态系统》2019,29(6):865-880

Implications of spatial variability of fish assemblages for monitoring of Australia's tropical estuaries     

Marcus Sheaves  Ross Johnston 《水产资源保护:海洋与淡水生态系统》2010,20(3):348-356

1. Although often seen as ideal targets for monitoring environmental change because of their high public profile, fish assemblages rarely appear as indicators in monitoring and reporting. 2. Published data were evaluated to develop a simple approach to quantifying the temporal consistency in assemblage structure suitable for routine monitoring and assessment. Data were examined as catch per unit effort (CPUE) and probability of encounter (PoE), and compared using three approaches with the potential to produce simple indices quantifying the patterns of similarity within an estuary over time: species richness, Bray‐Curtis Similarities and a new approach, DeltaPoE. Indices derived from published data were then tested against a time series of data from two estuarine lakes with a history of fish kills. 3. Multidimensional scaling based on PoE emphasizes the temporal consistency of fish assemblages within estuaries at least as well as one based on mean CPUE while providing operational advantages. Similarities based on PoE were more sensitive to change from ‘natural’ assemblage structure than the simpler indices and showed comparable results with Similarities from (log) CPUE data. The one drawback to Similarities is that their complex statistical formulation often makes them less effective vehicles for reporting and communication. Where this is the case the conceptual simplicity of DeltaPoE and its performance relative to Similarities suggests it is a good candidate from which to develop monitoring indices suitable for routine reporting. 4. The performance of each of the indices were considered against the known fish kills. Species richness tracked the observed changes, an expected outcome in this case because a major impact directly removed species. Both indices based on Similarities also tracked the changes faithfully. Of the two, Similarities based on PoE seemed to react more strongly to assemblage changes. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

How many fish use mangroves? The 75% rule an ill‐defined and poorly validated concept          下载免费PDF全文

Marcus Sheaves 《Fish and Fisheries》2017,18(4):778-789

Although mangroves are known to play a critical part in the lives and life histories of many fish species, these values have rarely been definitively quantified. Despite this, claims such as “an estimated 75% of commercially caught fish depend directly on mangroves” are common across a range of government and non‐government documents from around the world, to the extent that the idea that 75% or more of fish depend on mangroves has become a truism widely used to support the value of mangroves. I investigated the basis for these claims that I summarize as the “75% rule.” The “75% rule” is imprecisely defined, and invariably cannot be traced back to definitive scientific data. Moreover, the claim is illogical because we simply do not have adequate knowledge of how many fish occupy different habitats or even how many species of fish there actually are. Moreover, even when the simplest proposition, of how many species use mangroves, is tested using global data bases, the best estimates fall far short of 75%. Clearly, the “75% rule” is wildly inaccurate, unsubstantiated and, at least give our current knowledge and methods, impossible to substantiate. Mangroves are critical to many species but using an indefensible pseudoscientific paradigm such as this to support conservation efforts, management actions and legal decisions, greatly weakens any arguments that build upon it, putting at risk outcomes that rely on the integrity of the claim.  相似文献   

Context is more important than habitat type in determining use by juvenile fish     

Bradley  Michael  Baker  Ronald  Nagelkerken  Ivan  Sheaves  Marcus 《Landscape Ecology》2019,34(2):427-442

Context

Habitat characteristics are often equated with habitat function for animals. However, in heterogeneous landscapes, similar habitat types occur in different environmental contexts. In the marine realm, landscape studies have been confined to particular environments, rather than encompassing entire seascapes, due to incompatible sampling methods required in different situations.

Objectives

We examined the interactive structuring effects of local habitat characteristics and environmental context on assemblage composition.

Methods

We used a single technique—remote underwater video census—to explore the importance of habitat type (biotic structural components, substrate, and depth) and environmental context (marine vs estuarine) in structuring juvenile fish assemblages throughout an entire coastal region. In this model system, a range of structural habitat types were present in both estuarine and marine contexts.

Results

The 1315 video surveys collected show a clear hierarchy in the organisation of juvenile fish communities, with assemblages first distinguished by environmental context, then by habitat type. Marine and estuarine mangroves contained entirely different assemblages, and likewise for rocky reefs and submerged aquatic vegetation. Our results suggest that two functionally different ‘seascape nursery’ types exist at local scales within a single region, defined by their context.

Conclusions

The context of a location can be of greater significance in determining potential habitat function than what habitat-forming biota and substrates are present, and apparently similar habitat types in different contexts may be functionally distinct. These findings have important implications for local-scale management and conservation of juvenile fish habitats, particularly in regard to offsetting and restoration.

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