45 results on '"Schoeman DS"'
Search Results
2. Opposing life stage-specific effects of ocean warming at source and sink populations of range-shifting coral-reef fishes.
- Author
-
Monaco, CJ, Nagelkerken, I, Booth, DJ, Figueira, WF, Gillanders, BM, Schoeman, DS, Bradshaw, CJA, Monaco, CJ, Nagelkerken, I, Booth, DJ, Figueira, WF, Gillanders, BM, Schoeman, DS, and Bradshaw, CJA
- Abstract
Climate change is altering the latitudinal distributions of species, with their capacity to keep pace with a shifting climate depending on the stochastic expression of population growth rates, and the influence of compensatory density feedback on age-specific survival rates. We use population-abundance time series at the leading edge of an expanding species' range to quantify the contribution of stochastic environmental drivers and density feedbacks to the dynamics of life stage-specific population growth. Using a tropical, range-shifting Indo-Pacific damselfish (Abudefduf vaigiensis) as a model organism, we applied variants of the phenomenological Gompertz-logistic model to a 14-year dataset to quantify the relative importance of density feedback and stochastic environmental drivers on the separate and aggregated population growth rates of settler and juvenile life stages. The top-ranked models indicated that density feedback negatively affected the growth of tropical settlers and juveniles. Rates of settlement were negatively linked to temperatures experienced by parents at potential source populations in the tropics, but their subsequent survival and that of juveniles increased with the temperatures experienced at the temperate sink. Including these stochastic effects doubled the deviance explained by the models, corroborating an important role of temperature. By incorporating sea-surface temperature projections for the remainder of this century into these models, we anticipate improved conditions for the population growth of juvenile coral-reef fishes, but not for settlers in temperate ecosystems. Previous research has highlighted the association between temperature and the redistribution of species. Our analyses reveal the contrasting roles of different life stages in the dynamics of range-shifting species responding to climate change, as they transition from vagrancy to residency in their novel ranges.
- Published
- 2020
3. Historic dispersal barriers determine genetic structure and connectivity in a sandy beach brooder
- Author
-
Bezuidenhout, K, primary, Nel, R, additional, Schoeman, DS, additional, and Hauser, L, additional
- Published
- 2021
- Full Text
- View/download PDF
4. Open access solutions for biodiversity journals: Do not replace one problem with another
- Author
-
Peterson, AT, Anderson, RP, Beger, M, Bolliger, J, Brotons, L, Burridge, CP, Cobos, ME, Cuervo-Robayo, AP, Di Minin, E, Diez, J, Elith, J, Embling, CB, Escobar, LE, Essl, F, Feeley, KJ, Hawkes, L, Jiménez-García, D, Jimenez, L, Green, DM, Knop, E, Kühn, I, Lahoz-Monfort, JJ, Lira-Noriega, A, Lobo, JM, Loyola, R, Mac Nally, R, Machado-Stredel, F, Martínez-Meyer, E, McCarthy, M, Merow, C, Nori, J, Nuñez-Penichet, C, Osorio-Olvera, L, Pyšek, P, Rejmánek, M, Ricciardi, A, Robertson, M, Rojas Soto, O, Romero-Alvarez, D, Roura-Pascual, N, Santini, L, Schoeman, DS, Schröder, B, Soberon, J, Strubbe, D, Thuiller, W, Traveset, A, Treml, Eric, Václavík, T, Varela, S, Watson, JEM, Wiersma, Y, Wintle, B, Yanez-Arenas, C, Zurell, D, Peterson, AT, Anderson, RP, Beger, M, Bolliger, J, Brotons, L, Burridge, CP, Cobos, ME, Cuervo-Robayo, AP, Di Minin, E, Diez, J, Elith, J, Embling, CB, Escobar, LE, Essl, F, Feeley, KJ, Hawkes, L, Jiménez-García, D, Jimenez, L, Green, DM, Knop, E, Kühn, I, Lahoz-Monfort, JJ, Lira-Noriega, A, Lobo, JM, Loyola, R, Mac Nally, R, Machado-Stredel, F, Martínez-Meyer, E, McCarthy, M, Merow, C, Nori, J, Nuñez-Penichet, C, Osorio-Olvera, L, Pyšek, P, Rejmánek, M, Ricciardi, A, Robertson, M, Rojas Soto, O, Romero-Alvarez, D, Roura-Pascual, N, Santini, L, Schoeman, DS, Schröder, B, Soberon, J, Strubbe, D, Thuiller, W, Traveset, A, Treml, Eric, Václavík, T, Varela, S, Watson, JEM, Wiersma, Y, Wintle, B, Yanez-Arenas, C, and Zurell, D
- Published
- 2019
5. Classification of marine bioregions on the east coast of South Africa
- Author
-
Livingstone, T-C, primary, Harris, JM, additional, Lombard, AT, additional, Smit, AJ, additional, and Schoeman, DS, additional
- Published
- 2018
- Full Text
- View/download PDF
6. Functional replacement across species pools of vertebrate scavengers separated at a continental scale maintains an ecosystem function
- Author
-
Huijbers, CM, Schlacher, TA, Mcveigh, RR, Schoeman, DS, Olds, AD, Brown, MB, Ekanayake, Kasun Bandara, Weston, Michael, Connolly, RM, Huijbers, CM, Schlacher, TA, Mcveigh, RR, Schoeman, DS, Olds, AD, Brown, MB, Ekanayake, Kasun Bandara, Weston, Michael, and Connolly, RM
- Published
- 2016
7. From beans to breams: how participatory workshops can contribute to marine conservation planning
- Author
-
Wheeler, M, primary, Chambers, FMJ, additional, Sims-Castley, R, additional, Cowling, RM, additional, and Schoeman, DS, additional
- Published
- 2008
- Full Text
- View/download PDF
8. Bioassays for coastal water quality: an assessment using the larval development of Haliotis midae L
- Author
-
Shackleton, AL, primary, Schoeman, DS, additional, and Newman, BK, additional
- Published
- 2002
- Full Text
- View/download PDF
9. Dietary generalism accelerates arrival and persistence of coral‐reef fishes in their novel ranges under climate change
- Author
-
Monaco, CJ, Bradshaw, CJA, Booth, DJ, Gillanders, BM, Schoeman, DS, Nagelkerken, I, Monaco, CJ, Bradshaw, CJA, Booth, DJ, Gillanders, BM, Schoeman, DS, and Nagelkerken, I
10. Dietary generalism accelerates arrival and persistence of coral‐reef fishes in their novel ranges under climate change
- Author
-
Monaco, CJ, Bradshaw, CJA, Booth, DJ, Gillanders, BM, Schoeman, DS, Nagelkerken, I, Monaco, CJ, Bradshaw, CJA, Booth, DJ, Gillanders, BM, Schoeman, DS, and Nagelkerken, I
11. Effects of climate warming on energetics and habitat of the world's largest marine ectotherm.
- Author
-
Reynolds SD, Franklin CE, Norman BM, Richardson AJ, Everett JD, Schoeman DS, White CR, Lawson CL, Pierce SJ, Rohner CA, Bach SS, Comezzi FG, Diamant S, Jaidah MY, Robinson DP, and Dwyer RG
- Subjects
- Animals, Indian Ocean, Temperature, Sharks physiology, Climate Change, Ecosystem
- Abstract
Responses of organisms to climate warming are variable and complex. Effects on species distributions are already evident and mean global surface ocean temperatures are likely to warm by up to 4.1 °C by 2100, substantially impacting the physiology and distributions of ectotherms. The largest marine ectotherm, the whale shark Rhincodon typus, broadly prefers sea surface temperatures (SST) ranging from 23 to 30 °C. Whole-species distribution models have projected a poleward range shift under future scenarios of climate change, but these models do not consider intraspecific variation or phenotypic plasticity in thermal limits when modelling species responses, and the impact of climate warming on the energetic requirements of whale sharks is unknown. Using a dataset of 111 whale shark movement tracks from aggregation sites in five countries across the Indian Ocean and the latest Earth-system modelling produced from Coupled Model Intercomparison Project Phase 6 for the Intergovernmental Panel on Climate Change, we examined how SST and total zooplankton biomass, their main food source, may change in the future, and what this means for the energetic balance and extent of suitable habitat for whale sharks. Earth System Models, under three Shared Socioeconomic Pathways (SSPs; SSP1-2.6, SSP3-7.0 and SSP5-8.5), project that by 2100 mean SST in four regions where whale shark aggregations are found will increase by up to 4.9 °C relative to the present, while zooplankton biomass will decrease. This reduction in zooplankton is projected to be accompanied by an increase in the energetic requirements of whale sharks because warmer water temperatures will increase their metabolic rate. We found marked differences in projected changes in the extent of suitable habitat when comparing a whole-species distribution model to one including regional variation. This suggests that the conventional approach of combining data from different regions within a species' distribution could underestimate the amount of local adaptation in populations, although parameterising local models could also suffer from having insufficient data and lead to model mis-specification or highly uncertain estimates. Our study highlights the need for further research into whale shark thermal tolerances and energetics, the complexities involved in projecting species responses to climate change, and the potential importance of considering intraspecific variation when building species distribution models., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Samantha D. Reynolds reports financial support was provided by Australian Government. Samantha D. Reynolds reports financial support was provided by Thyne Reid Foundation Ltd. Samantha D. Reynolds reports financial support was provided by Holsworth Wildlife Research Endowment. Bradley M. Norman reports financial support was provided by Winifred Violet Scott Charitable Trust. Funders had no role in the analysis and interpretation of the data, writing of the manuscript or in the decision to submit the manuscript for publication. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
12. Global dominance of lianas over trees is driven by forest disturbance, climate and topography.
- Author
-
Ngute ASK, Schoeman DS, Pfeifer M, van der Heijden GMF, Phillips OL, van Breugel M, Campbell MJ, Chandler CJ, Enquist BJ, Gallagher RV, Gehring C, Hall JS, Laurance S, Laurance WF, Letcher SG, Liu W, Sullivan MJP, Wright SJ, Yuan C, and Marshall AR
- Subjects
- Forests, Carbon Sequestration, Water, Trees physiology, Tropical Climate
- Abstract
Growing evidence suggests that liana competition with trees is threatening the global carbon sink by slowing the recovery of forests following disturbance. A recent theory based on local and regional evidence further proposes that the competitive success of lianas over trees is driven by interactions between forest disturbance and climate. We present the first global assessment of liana-tree relative performance in response to forest disturbance and climate drivers. Using an unprecedented dataset, we analysed 651 vegetation samples representing 26,538 lianas and 82,802 trees from 556 unique locations worldwide, derived from 83 publications. Results show that lianas perform better relative to trees (increasing liana-to-tree ratio) when forests are disturbed, under warmer temperatures and lower precipitation and towards the tropical lowlands. We also found that lianas can be a critical factor hindering forest recovery in disturbed forests experiencing liana-favourable climates, as chronosequence data show that high competitive success of lianas over trees can persist for decades following disturbances, especially when the annual mean temperature exceeds 27.8°C, precipitation is less than 1614 mm and climatic water deficit is more than 829 mm. These findings reveal that degraded tropical forests with environmental conditions favouring lianas are disproportionately more vulnerable to liana dominance and thus can potentially stall succession, with important implications for the global carbon sink, and hence should be the highest priority to consider for restoration management., (© 2024 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)
- Published
- 2024
- Full Text
- View/download PDF
13. Demystifying global climate models for use in the life sciences.
- Author
-
Schoeman DS, Gupta AS, Harrison CS, Everett JD, Brito-Morales I, Hannah L, Bopp L, Roehrdanz PR, and Richardson AJ
- Subjects
- Humans, Forecasting, Climate Models, Climate Change
- Abstract
For each assessment cycle of the Intergovernmental Panel on Climate Change (IPCC), researchers in the life sciences are called upon to provide evidence to policymakers planning for a changing future. This research increasingly relies on highly technical and complex outputs from climate models. The strengths and weaknesses of these data may not be fully appreciated beyond the climate modelling community; therefore, uninformed use of raw or preprocessed climate data could lead to overconfident or spurious conclusions. We provide an accessible introduction to climate model outputs that is intended to empower the life science community to robustly address questions about human and natural systems in a changing world., Competing Interests: Declaration of interests The authors declare no conflicts of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
14. A metric-based framework for climate-smart conservation planning.
- Author
-
Buenafe KCV, Dunn DC, Everett JD, Brito-Morales I, Schoeman DS, Hanson JO, Dabalà A, Neubert S, Cannicci S, Kaschner K, and Richardson AJ
- Subjects
- Hydrogen-Ion Concentration, Biodiversity, Uncertainty, Climate Change, Ecosystem, Conservation of Natural Resources methods, Seawater
- Abstract
Climate change is already having profound effects on biodiversity, but climate change adaptation has yet to be fully incorporated into area-based management tools used to conserve biodiversity, such as protected areas. One main obstacle is the lack of consensus regarding how impacts of climate change can be included in spatial conservation plans. We propose a climate-smart framework that prioritizes the protection of climate refugia-areas of low climate exposure and high biodiversity retention-using climate metrics. We explore four aspects of climate-smart conservation planning: (1) climate model ensembles; (2) multiple emission scenarios; (3) climate metrics; and (4) approaches to identifying climate refugia. We illustrate this framework in the Western Pacific Ocean, but it is equally applicable to terrestrial systems. We found that all aspects of climate-smart conservation planning considered affected the configuration of spatial plans. The choice of climate metrics and approaches to identifying refugia have large effects in the resulting climate-smart spatial plans, whereas the choice of climate models and emission scenarios have smaller effects. As the configuration of spatial plans depended on climate metrics used, a spatial plan based on a single measure of climate change (e.g., warming) will not necessarily be robust against other measures of climate change (e.g., ocean acidification). We therefore recommend using climate metrics most relevant for the biodiversity and region considered based on a single or multiple climate drivers. To include the uncertainty associated with different climate futures, we recommend using multiple climate models (i.e., an ensemble) and emission scenarios. Finally, we show that the approaches we used to identify climate refugia feature trade-offs between: (1) the degree to which they are climate-smart, and (2) their efficiency in meeting conservation targets. Hence, the choice of approach will depend on the relative value that stakeholders place on climate adaptation. By using this framework, protected areas can be designed with improved longevity and thus safeguard biodiversity against current and future climate change. We hope that the proposed climate-smart framework helps transition conservation planning toward climate-smart approaches., (© 2023 The Authors. Ecological Applications published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)
- Published
- 2023
- Full Text
- View/download PDF
15. First report of Kudoa thunni and Kudoa musculoliquefaciens affecting the quality of commercially harvested yellowfin tuna and broadbill swordfish in Eastern Australia.
- Author
-
Bolin JA, Cummins SF, Mitu SA, Schoeman DS, Evans KJ, and Scales KL
- Subjects
- Animals, Australia, DNA, Ribosomal genetics, Fish Diseases epidemiology, Fish Diseases parasitology, Muscles parasitology, Myxozoa anatomy & histology, Myxozoa genetics, Pacific Ocean, Parasitic Diseases, Animal epidemiology, Parasitic Diseases, Animal parasitology, Phylogeny, RNA, Ribosomal, 18S genetics, RNA, Ribosomal, 28S genetics, Seafood parasitology, Species Specificity, Fishes parasitology, Myxozoa classification, Tuna parasitology
- Abstract
Recent anecdotal reports from seafood processors in eastern Australia have described an increased occurrence of post-mortem myoliquefaction ('jellymeat') in broadbill swordfish Xiphias gladius, and macroscopic cysts throughout the musculature of yellowfin tuna Thunnus albacares. A genus of parasitic cnidarians, Kudoa (Myxosporea, Multivalvulida), species of which are known to occur in economically important wild-caught fish species globally, can cause similar quality-deterioration issues. However, Kudoa sp. epizootiology within commercially harvested, high-value fish caught within Australia is poorly understood, despite the parasite's economic importance. To determine the causative agent responsible for the observed quality deterioration in swordfish and yellowfin tuna, muscle-tissue samples from seafood processors in Mooloolaba, Australia, collected from October 2019-February 2020, were examined for parasitic infection. Kudoid myxospores were identified from both hosts and were subquadrate in shape, with four equal-sized polar capsules. The SSU rDNA sequences from both fish shared > 99% identity to Kudoa species. Kudoa musculoliquefaciens was isolated from 87.1% of swordfish sampled, suggesting that it is a widespread parasite in swordfish from the southwest Pacific Ocean. This study provides the first molecular and morphological characterisation of Kudoa thunni in yellowfin tuna and K. musculoliquefaciens in swordfish harvested from the waters of eastern Australia, expanding the geographical distribution of K. thunni and K. musculoliquefaciens to include the Coral and Tasman Seas. We demonstrate that not all infected swordfish progress to jellymeat, show the usefulness of molecular tools for reliably identifying infection by Kudoa spp., and add to the overall knowledge of kudoid epizootiology in wild-caught fish.
- Published
- 2021
- Full Text
- View/download PDF
16. Quantifying finer-scale behaviours using self-organising maps (SOMs) to link accelerometery signatures with behavioural patterns in free-roaming terrestrial animals.
- Author
-
Galea N, Murphy F, Gaschk JL, Schoeman DS, and Clemente CJ
- Subjects
- Animals, Cats, Female, Male, Accelerometry, Behavior, Animal physiology, Ecosystem, Supervised Machine Learning
- Abstract
Collecting quantitative information on animal behaviours is difficult, especially from cryptic species or species that alter natural behaviours under observation. Using harness-mounted tri-axial accelerometers free-roaming domestic cats (Felis Catus) we developed a methodology that can precisely classify finer-scale behaviours. We further tested the effect of a prey-protector device designed to reduce prey capture. We aligned accelerometer traces collected at 50 Hz with video files (60 fps) and labelled 12 individual behaviours, then trained a supervised machine-learning algorithm using Kohonen super self-organising maps (SOM). The SOM was able to predict individual behaviours with a ~ 99.6% overall accuracy, which was slightly better than for random forest estimates using the same dataset (98.9%). There was a significant effect of sample size, with precision and sensitivity decreasing rapidly below 2000 1-s observations. We were also able to detect a behaviour specific reduction in the predictability when cats were fitted with the prey-protector device indicating it altered biomechanical gait. Our results can be applied in movement ecology, zoology and conservation, where habitat specific movement performance between predators or prey may be critical to managing species of conservation significance, or in veterinary and agricultural fields, where early detection of movement pathologies can improve animal welfare.
- Published
- 2021
- Full Text
- View/download PDF
17. Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels.
- Author
-
Sydeman WJ, Schoeman DS, Thompson SA, Hoover BA, García-Reyes M, Daunt F, Agnew P, Anker-Nilssen T, Barbraud C, Barrett R, Becker PH, Bell E, Boersma PD, Bouwhuis S, Cannell B, Crawford RJM, Dann P, Delord K, Elliott G, Erikstad KE, Flint E, Furness RW, Harris MP, Hatch S, Hilwig K, Hinke JT, Jahncke J, Mills JA, Reiertsen TK, Renner H, Sherley RB, Surman C, Taylor G, Thayer JA, Trathan PN, Velarde E, Walker K, Wanless S, Warzybok P, and Watanuki Y
- Abstract
Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2021
- Full Text
- View/download PDF
18. Global warming is causing a more pronounced dip in marine species richness around the equator.
- Author
-
Chaudhary C, Richardson AJ, Schoeman DS, and Costello MJ
- Subjects
- Biomass, Aquatic Organisms physiology, Biodiversity, Global Warming
- Abstract
The latitudinal gradient in species richness, with more species in the tropics and richness declining with latitude, is widely known and has been assumed to be stable over recent centuries. We analyzed data on 48,661 marine animal species since 1955, accounting for sampling variation, to assess whether the global latitudinal gradient in species richness is being impacted by climate change. We confirm recent studies that show a slight dip in species richness at the equator. Moreover, richness across latitudinal bands was sensitive to temperature, reaching a plateau or declining above a mean annual sea surface temperature of 20 °C for most taxa. In response, since the 1970s, species richness has declined at the equator relative to an increase at midlatitudes and has shifted north in the northern hemisphere, particularly among pelagic species. This pattern is consistent with the hypothesis that climate change is impacting the latitudinal gradient in marine biodiversity at a global scale. The intensification of the dip in species richness at the equator, especially for pelagic species, suggests that it is already too warm there for some species to survive., Competing Interests: The authors declare no competing interest.
- Published
- 2021
- Full Text
- View/download PDF
19. Opposing life stage-specific effects of ocean warming at source and sink populations of range-shifting coral-reef fishes.
- Author
-
Monaco CJ, Nagelkerken I, Booth DJ, Figueira WF, Gillanders BM, Schoeman DS, and Bradshaw CJA
- Subjects
- Animals, Climate Change, Coral Reefs, Fishes, Oceans and Seas, Anthozoa, Ecosystem
- Abstract
Climate change is altering the latitudinal distributions of species, with their capacity to keep pace with a shifting climate depending on the stochastic expression of population growth rates, and the influence of compensatory density feedback on age-specific survival rates. We use population-abundance time series at the leading edge of an expanding species' range to quantify the contribution of stochastic environmental drivers and density feedbacks to the dynamics of life stage-specific population growth. Using a tropical, range-shifting Indo-Pacific damselfish (Abudefduf vaigiensis) as a model organism, we applied variants of the phenomenological Gompertz-logistic model to a 14-year dataset to quantify the relative importance of density feedback and stochastic environmental drivers on the separate and aggregated population growth rates of settler and juvenile life stages. The top-ranked models indicated that density feedback negatively affected the growth of tropical settlers and juveniles. Rates of settlement were negatively linked to temperatures experienced by parents at potential source populations in the tropics, but their subsequent survival and that of juveniles increased with the temperatures experienced at the temperate sink. Including these stochastic effects doubled the deviance explained by the models, corroborating an important role of temperature. By incorporating sea-surface temperature projections for the remainder of this century into these models, we anticipate improved conditions for the population growth of juvenile coral-reef fishes, but not for settlers in temperate ecosystems. Previous research has highlighted the association between temperature and the redistribution of species. Our analyses reveal the contrasting roles of different life stages in the dynamics of range-shifting species responding to climate change, as they transition from vagrancy to residency in their novel ranges., (© 2020 British Ecological Society.)
- Published
- 2021
- Full Text
- View/download PDF
20. Dietary generalism accelerates arrival and persistence of coral-reef fishes in their novel ranges under climate change.
- Author
-
Monaco CJ, Bradshaw CJA, Booth DJ, Gillanders BM, Schoeman DS, and Nagelkerken I
- Subjects
- Animals, Coral Reefs, Diet, Fishes, Anthozoa, Climate Change
- Abstract
Climate change is redistributing marine and terrestrial species globally. Life-history traits mediate the ability of species to cope with novel environmental conditions, and can be used to gauge the potential redistribution of taxa facing the challenges of a changing climate. However, it is unclear whether the same traits are important across different stages of range shifts (arrival, population increase, persistence). To test which life-history traits most mediate the process of range extension, we used a 16-year dataset of 35 range-extending coral-reef fish species and quantified the importance of various traits on the arrival time (earliness) and degree of persistence (prevalence and patchiness) at higher latitudes. We show that traits predisposing species to shift their range more rapidly (large body size, broad latitudinal range, long dispersal duration) did not drive the early stages of redistribution. Instead, we found that as diet breadth increased, the initial arrival and establishment (prevalence and patchiness) of climate migrant species in temperate locations occurred earlier. While the initial incursion of range-shifting species depends on traits associated with dispersal potential, subsequent establishment hinges more on a species' ability to exploit novel food resources locally. These results highlight that generalist species that can best adapt to novel food sources might be most successful in a future ocean., (© 2020 John Wiley & Sons Ltd.)
- Published
- 2020
- Full Text
- View/download PDF
21. Marine heat waves threaten kelp forests.
- Author
-
Arafeh-Dalmau N, Schoeman DS, Montaño-Moctezuma G, Micheli F, Rogers-Bennett L, Olguin-Jacobson C, and Possingham HP
- Subjects
- Pacific Ocean, Endangered Species, Global Warming, Kelp
- Published
- 2020
- Full Text
- View/download PDF
22. Sea animals are more vulnerable to warming than are land ones.
- Author
-
Richardson AJ and Schoeman DS
- Subjects
- Animals, Climate, Climate Change
- Published
- 2019
- Full Text
- View/download PDF
23. Climate Velocity Can Inform Conservation in a Warming World.
- Author
-
Brito-Morales I, García Molinos J, Schoeman DS, Burrows MT, Poloczanska ES, Brown CJ, Ferrier S, Harwood TD, Klein CJ, McDonald-Madden E, Moore PJ, Pandolfi JM, Watson JEM, Wenger AS, and Richardson AJ
- Subjects
- Global Warming, Oceans and Seas, Biodiversity, Climate Change, Conservation of Natural Resources
- Abstract
Climate change is shifting the ranges of species. Simple predictive metrics of range shifts such as climate velocity, that do not require extensive knowledge or data on individual species, could help to guide conservation. We review research on climate velocity, describing the theory underpinning the concept and its assumptions. We highlight how climate velocity has already been applied in conservation-related research, including climate residence time, climate refugia, endemism, historic and projected range shifts, exposure to climate change, and climate connectivity. Finally, we discuss ways to enhance the use of climate velocity in conservation through tailoring it to be more biologically meaningful, informing design of protected areas, conserving ocean biodiversity in 3D, and informing conservation actions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
24. Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects.
- Author
-
Jaramillo E, Dugan JE, Hubbard DM, Contreras H, Duarte C, Acuña E, and Schoeman DS
- Subjects
- Animals, Body Size, Climate Change, Crustacea
- Abstract
Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal ecosystem, and for one species, across hemispheres in this space-for-time substitution, suggests predictions of ecosystem responses to thermal effects of climate change may potentially be generalised, with important implications for coastal conservation.
- Published
- 2017
- Full Text
- View/download PDF
25. Optimising Land-Sea Management for Inshore Coral Reefs.
- Author
-
Gilby BL, Olds AD, Connolly RM, Stevens T, Henderson CJ, Maxwell PS, Tibbetts IR, Schoeman DS, Rissik D, and Schlacher TA
- Subjects
- Bayes Theorem, Models, Statistical, Conservation of Natural Resources methods, Coral Reefs, Oceans and Seas
- Abstract
Management authorities seldom have the capacity to comprehensively address the full suite of anthropogenic stressors, particularly in the coastal zone where numerous threats can act simultaneously to impact reefs and other ecosystems. This situation requires tools to prioritise management interventions that result in optimum ecological outcomes under a set of constraints. Here we develop one such tool, introducing a Bayesian Belief Network to model the ecological condition of inshore coral reefs in Moreton Bay (Australia) under a range of management actions. Empirical field data was used to model a suite of possible ecological responses of coral reef assemblages to five key management actions both in the sea (e.g. expansion of reserves, mangrove & seagrass restoration, fishing restrictions) and on land (e.g. lower inputs of sediment and sewage from treatment plants). Models show that expanding marine reserves (a 'marine action') and reducing sediment inputs from the catchments (a 'land action') were the most effective investments to achieve a better status of reefs in the Bay, with both having been included in >58% of scenarios with positive outcomes, and >98% of the most effective (5th percentile) scenarios. Heightened fishing restrictions, restoring habitats, and reducing nutrient discharges from wastewater treatment plants have additional, albeit smaller effects. There was no evidence that combining individual management actions would consistently produce sizeable synergistic until after maximum investment on both marine reserves (i.e. increasing reserve extent from 31 to 62% of reefs) and sediments (i.e. rehabilitating 6350 km of waterways within catchments to reduce sediment loads by 50%) were implemented. The method presented here provides a useful tool to prioritize environmental actions in situations where multiple competing management interventions exist for coral reefs and in other systems subjected to multiple stressor from the land and the sea., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2016
- Full Text
- View/download PDF
26. Regional drivers of clutch loss reveal important trade-offs for beach-nesting birds.
- Author
-
Maslo B, Schlacher TA, Weston MA, Huijbers CM, Anderson C, Gilby BL, Olds AD, Connolly RM, and Schoeman DS
- Abstract
Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia. Of the 132 model nests deployed and monitored with cameras, 45 (34%) survived the experimental exposure period. Thirty-five (27%) were lost to flooding, 32 (24%) were depredated, nine (7%) buried by sand, seven (5%) destroyed by people, three (2%) failed by unknown causes, and one (1%) was destroyed by a dog. Clutch fate differed substantially among regions, particularly with respect to losses from flooding and predation. 'Topographic' exposure was the main driver of mortality of nests placed close to the drift line near the base of dunes, which were lost to waves (particularly during storms) and to a lesser extent depredation. Predators determined the fate of clutches not lost to waves, with the depredation probability largely influenced by region. Depredation probability declined as nests were backed by higher dunes and were placed closer to vegetation. This study emphasizes the scale at which clutch fate and survival varies within a regional context, the prominence of corvids as egg predators, the significant role of flooding as a source of nest loss, and the multiple trade-offs faced by beach-nesting birds and those that manage them., Competing Interests: The authors declare there are no competing interests.
- Published
- 2016
- Full Text
- View/download PDF
27. Ecological and methodological drivers of species' distribution and phenology responses to climate change.
- Author
-
Brown CJ, O'Connor MI, Poloczanska ES, Schoeman DS, Buckley LB, Burrows MT, Duarte CM, Halpern BS, Pandolfi JM, Parmesan C, and Richardson AJ
- Subjects
- Aquatic Organisms, Models, Theoretical, Population Dynamics, Seasons, Climate Change, Ecology methods
- Abstract
Climate change is shifting species' distribution and phenology. Ecological traits, such as mobility or reproductive mode, explain variation in observed rates of shift for some taxa. However, estimates of relationships between traits and climate responses could be influenced by how responses are measured. We compiled a global data set of 651 published marine species' responses to climate change, from 47 papers on distribution shifts and 32 papers on phenology change. We assessed the relative importance of two classes of predictors of the rate of change, ecological traits of the responding taxa and methodological approaches for quantifying biological responses. Methodological differences explained 22% of the variation in range shifts, more than the 7.8% of the variation explained by ecological traits. For phenology change, methodological approaches accounted for 4% of the variation in measurements, whereas 8% of the variation was explained by ecological traits. Our ability to predict responses from traits was hindered by poor representation of species from the tropics, where temperature isotherms are moving most rapidly. Thus, the mean rate of distribution change may be underestimated by this and other global syntheses. Our analyses indicate that methodological approaches should be explicitly considered when designing, analysing and comparing results among studies. To improve climate impact studies, we recommend that (1) reanalyses of existing time series state how the existing data sets may limit the inferences about possible climate responses; (2) qualitative comparisons of species' responses across different studies be limited to studies with similar methodological approaches; (3) meta-analyses of climate responses include methodological attributes as covariates; and (4) that new time series be designed to include the detection of early warnings of change or ecologically relevant change. Greater consideration of methodological attributes will improve the accuracy of analyses that seek to quantify the role of climate change in species' distribution and phenology changes., (© 2015 John Wiley & Sons Ltd.)
- Published
- 2016
- Full Text
- View/download PDF
28. Resource type influences the effects of reserves and connectivity on ecological functions.
- Author
-
Yabsley NA, Olds AD, Connolly RM, Martin TS, Gilby BL, Maxwell PS, Huijbers CM, Schoeman DS, and Schlacher TA
- Subjects
- Animals, Anthozoa, Food Chain, Microalgae growth & development, Queensland, Seaweed growth & development, Conservation of Natural Resources, Coral Reefs, Fishes physiology, Herbivory
- Abstract
Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context. The removal of algae by herbivorous fish is a key ecological function on coral reefs that promotes coral growth and recruitment. Many reef herbivores are harvested and some use other habitats (like mangroves) as nurseries or feeding areas. Thus, the effects of habitat connectivity and marine reserves can jointly promote herbivore populations on coral reefs, thereby influencing reef health. We used a coral reef seascape in eastern Australia to test whether seascape connectivity and reserves influence herbivory. We measured herbivore abundance and rates of herbivory (on turf algae and macroalgae) on reefs that differed in both their level of connectivity to adjacent mangrove habitats and their level of protection from fishing. Reserves enhanced the biomass of herbivorous fish on coral reefs in all seascape settings and promoted consumption of turf algae. Consumption of turf algae was correlated with the biomass of surgeonfish that are exploited outside reserves. By contrast, both reserve status and connectivity influenced herbivory on macroalgae. Consumption of macroalgae was greatest on fished reefs that were far from mangroves and was not strongly correlated with any fish species. Our findings demonstrate that landscape connectivity and reserve status can jointly affect the functioning of ecosystems. Moreover, we show that reserve and connectivity effects can differ markedly depending on resource type (in this case turf algae vs. macroalgae). The effectiveness of conservation initiatives will therefore depend on our ability to understand how these multiple interactive effects structure the distribution of ecological functions. These findings have wider implications for the spatial conservation of heterogeneous environments and strengthen the case that the impact of conservation on ecosystem functioning is contingent on how reserves are positioned in landscapes., (© 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.)
- Published
- 2016
- Full Text
- View/download PDF
29. Edging along a Warming Coast: A Range Extension for a Common Sandy Beach Crab.
- Author
-
Schoeman DS, Schlacher TA, Jones AR, Murray A, Huijbers CM, Olds AD, and Connolly RM
- Subjects
- Animals, Australia, Climate Change, Ecosystem, Oceans and Seas, Brachyura growth & development
- Abstract
Determining the position of range edges is the first step in developing an understanding of the ecological and evolutionary dynamics in play as species' ranges shift in response to climate change. Here, we study the leading (poleward) range edge of Ocypode cordimanus, a ghost crab that is common along the central to northern east coast of Australia. Our study establishes the poleward range edge of adults of this species to be at Merimbula (36.90°S, 149.93°E), 270 km (along the coast) south of the previous southernmost museum record. We also establish that dispersal of pelagic larvae results in recruitment to beaches 248 km (along the coast; 0.9° of latitude) beyond the adult range edge we have documented here. Although we cannot conclusively demonstrate that the leading range edge for this species has moved polewards in response to climate change, this range edge does fall within a "hotspot" of ocean warming, where surface isotherms are moving southwards along the coast at 20-50 km.decade-1; coastal air temperatures in the region are also warming. If these patterns persist, future range extensions could be anticipated. On the basis of their ecology, allied with their occupancy of ocean beaches, which are home to taxa that are particularly amenable to climate-change studies, we propose that ghost crabs like O. cordimanus represent ideal model organisms with which to study ecological and evolutionary processes associated with climate change. The fact that "hotspots" of ocean warming on four other continents correspond with poleward range edges of ghost crab species suggests that results of hypothesis tests could be generalized, yielding excellent opportunities to rapidly progress knowledge in this field.
- Published
- 2015
- Full Text
- View/download PDF
30. Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches.
- Author
-
Brown MB, Schlacher TA, Schoeman DS, Weston MA, Huijbers CM, Olds AD, and Connolly RM
- Subjects
- Animals, Australia, Islands, Rats, Swine, Birds physiology, Food Chain, Foxes, Introduced Species, Predatory Behavior physiology
- Abstract
Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events among species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune-beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilization. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: (1) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and (2) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores.
- Published
- 2015
- Full Text
- View/download PDF
31. Ocean zoning for conservation, fisheries and marine renewable energy: assessing trade-offs and co-location opportunities.
- Author
-
Yates KL, Schoeman DS, and Klein CJ
- Subjects
- Northern Ireland, Conservation of Natural Resources methods, Fisheries methods, Oceans and Seas, Renewable Energy
- Abstract
Oceans, particularly coastal areas, are getting busier and within this increasingly human-dominated seascape, marine biodiversity continues to decline. Attempts to maintain and restore marine biodiversity are becoming more spatial, principally through the designation of marine protected areas (MPAs). MPAs compete for space with other uses, and the emergence of new industries, such as marine renewable energy generation, will increase competition for space. Decision makers require guidance on how to zone the ocean to conserve biodiversity, mitigate conflict and accommodate multiple uses. Here we used empirical data and freely available planning software to identified priority areas for multiple ocean zones, which incorporate goals for biodiversity conservation, two types of renewable energy, and three types of fishing. We developed an approached to evaluate trade-offs between industries and we investigated the impacts of co-locating some fishing activities within renewable energy sites. We observed non-linear trade-offs between industries. We also found that different subsectors within those industries experienced very different trade-off curves. Incorporating co-location resulted in significant reductions in cost to the fishing industry, including fisheries that were not co-located. Co-location also altered the optimal location of renewable energy zones with planning solutions. Our findings have broad implications for ocean zoning and marine spatial planning. In particular, they highlight the need to include industry subsectors when assessing trade-offs and they stress the importance of considering co-location opportunities from the outset. Our research reinforces the need for multi-industry ocean-zoning and demonstrates how it can be undertaken within the framework of strategic conservation planning., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
32. Metrics to assess ecological condition, change, and impacts in sandy beach ecosystems.
- Author
-
Schlacher TA, Schoeman DS, Jones AR, Dugan JE, Hubbard DM, Defeo O, Peterson CH, Weston MA, Maslo B, Olds AD, Scapini F, Nel R, Harris LR, Lucrezi S, Lastra M, Huijbers CM, and Connolly RM
- Subjects
- Bathing Beaches, Conservation of Natural Resources methods, Ecosystem, Environmental Monitoring methods, Models, Biological
- Abstract
Complexity is increasingly the hallmark in environmental management practices of sandy shorelines. This arises primarily from meeting growing public demands (e.g., real estate, recreation) whilst reconciling economic demands with expectations of coastal users who have modern conservation ethics. Ideally, shoreline management is underpinned by empirical data, but selecting ecologically-meaningful metrics to accurately measure the condition of systems, and the ecological effects of human activities, is a complex task. Here we construct a framework for metric selection, considering six categories of issues that authorities commonly address: erosion; habitat loss; recreation; fishing; pollution (litter and chemical contaminants); and wildlife conservation. Possible metrics were scored in terms of their ability to reflect environmental change, and against criteria that are widely used for judging the performance of ecological indicators (i.e., sensitivity, practicability, costs, and public appeal). From this analysis, four types of broadly applicable metrics that also performed very well against the indicator criteria emerged: 1.) traits of bird populations and assemblages (e.g., abundance, diversity, distributions, habitat use); 2.) breeding/reproductive performance sensu lato (especially relevant for birds and turtles nesting on beaches and in dunes, but equally applicable to invertebrates and plants); 3.) population parameters and distributions of vertebrates associated primarily with dunes and the supralittoral beach zone (traditionally focused on birds and turtles, but expandable to mammals); 4.) compound measurements of the abundance/cover/biomass of biota (plants, invertebrates, vertebrates) at both the population and assemblage level. Local constraints (i.e., the absence of birds in highly degraded urban settings or lack of dunes on bluff-backed beaches) and particular issues may require alternatives. Metrics - if selected and applied correctly - provide empirical evidence of environmental condition and change, but often do not reflect deeper environmental values per se. Yet, values remain poorly articulated for many beach systems; this calls for a comprehensive identification of environmental values and the development of targeted programs to conserve these values on sandy shorelines globally., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
33. Climate-change impacts on sandy-beach biota: crossing a line in the sand.
- Author
-
Schoeman DS, Schlacher TA, and Defeo O
- Subjects
- Animals, Biota, Ecosystem, Invertebrates, Nesting Behavior, South America, Turtles, Bathing Beaches, Climate Change
- Abstract
Sandy ocean beaches are iconic assets that provide irreplaceable ecosystem services to society. Despite their great socioeconomic importance, beaches as ecosystems are severely under-represented in the literature on climate-change ecology. Here, we redress this imbalance by examining whether beach biota have been observed to respond to recent climate change in ways that are consistent with expectations under climate change. We base our assessments on evidence coming from case studies on beach invertebrates in South America and on sea turtles globally. Surprisingly, we find that observational evidence for climate-change responses in beach biota is more convincing for invertebrates than for highly charismatic turtles. This asymmetry is paradoxical given the better theoretical understanding of the mechanisms by which turtles are likely to respond to changes in climate. Regardless of this disparity, knowledge of the unique attributes of beach systems can complement our detection of climate-change impacts on sandy-shore invertebrates to add rigor to studies of climate-change ecology for sandy beaches. To this end, we combine theory from beach ecology and climate-change ecology to put forward a suite of predictive hypotheses regarding climate impacts on beaches and to suggest ways that these can be tested. Addressing these hypotheses could significantly advance both beach and climate-change ecology, thereby progressing understanding of how future climate change will impact coastal ecosystems more generally.
- Published
- 2014
- Full Text
- View/download PDF
34. Climate change. Climate change and wind intensification in coastal upwelling ecosystems.
- Author
-
Sydeman WJ, García-Reyes M, Schoeman DS, Rykaczewski RR, Thompson SA, Black BA, and Bograd SJ
- Subjects
- California, Greenhouse Effect, Climate Change, Ecosystem, Wind
- Abstract
In 1990, Andrew Bakun proposed that increasing greenhouse gas concentrations would force intensification of upwelling-favorable winds in eastern boundary current systems that contribute substantial services to society. Because there is considerable disagreement about whether contemporary wind trends support Bakun's hypothesis, we performed a meta-analysis of the literature on upwelling-favorable wind intensification. The preponderance of published analyses suggests that winds have intensified in the California, Benguela, and Humboldt upwelling systems and weakened in the Iberian system over time scales ranging up to 60 years; wind change is equivocal in the Canary system. Stronger intensification signals are observed at higher latitudes, consistent with the warming pattern associated with climate change. Overall, reported changes in coastal winds, although subtle and spatially variable, support Bakun's hypothesis of upwelling intensification in eastern boundary current systems., (Copyright © 2014, American Association for the Advancement of Science.)
- Published
- 2014
- Full Text
- View/download PDF
35. Geographical limits to species-range shifts are suggested by climate velocity.
- Author
-
Burrows MT, Schoeman DS, Richardson AJ, Molinos JG, Hoffmann A, Buckley LB, Moore PJ, Brown CJ, Bruno JF, Duarte CM, Halpern BS, Hoegh-Guldberg O, Kappel CV, Kiessling W, O'Connor MI, Pandolfi JM, Parmesan C, Sydeman WJ, Ferrier S, Williams KJ, and Poloczanska ES
- Subjects
- Animals, Australia, Biodiversity, Models, Theoretical, Population Dynamics, Seawater, Temperature, Time Factors, Uncertainty, Animal Migration, Climate, Climate Change, Ecosystem, Geographic Mapping, Geography
- Abstract
The reorganization of patterns of species diversity driven by anthropogenic climate change, and the consequences for humans, are not yet fully understood or appreciated. Nevertheless, changes in climate conditions are useful for predicting shifts in species distributions at global and local scales. Here we use the velocity of climate change to derive spatial trajectories for climatic niches from 1960 to 2009 (ref. 7) and from 2006 to 2100, and use the properties of these trajectories to infer changes in species distributions. Coastlines act as barriers and locally cooler areas act as attractors for trajectories, creating source and sink areas for local climatic conditions. Climate source areas indicate where locally novel conditions are not connected to areas where similar climates previously occurred, and are thereby inaccessible to climate migrants tracking isotherms: 16% of global surface area for 1960 to 2009, and 34% of ocean for the 'business as usual' climate scenario (representative concentration pathway (RCP) 8.5) representing continued use of fossil fuels without mitigation. Climate sink areas are where climate conditions locally disappear, potentially blocking the movement of climate migrants. Sink areas comprise 1.0% of ocean area and 3.6% of land and are prevalent on coasts and high ground. Using this approach to infer shifts in species distributions gives global and regional maps of the expected direction and rate of shifts of climate migrants, and suggests areas of potential loss of species richness.
- Published
- 2014
- Full Text
- View/download PDF
36. Long‐term monitoring reveals differing impacts of elephants on elements of a canopy shrub community.
- Author
-
Landman M, Schoeman DS, Hall-Martin AJ, and Kerley GIH
- Subjects
- Animals, Conservation of Natural Resources methods, South Africa, Time Factors, Biodiversity, Elephants physiology, Environmental Monitoring methods
- Abstract
The conservation management of southern Africa's elephants focuses on identifying and mitigating the extent and intensity of impacts on biological diversity. However, variation in the intensity of elephant effects between elements of biodiversity is seldom explored, which limits our ability to interpret the scale of the impacts. Our study quantifies >50 years of impacts in the succulent thickets of the Addo Elephant National Park, South Africa, contrasting hypotheses for the resilience of the canopy shrubs (a key functional guild) to elephants with those that argue the opposite. We also assess the impacts between elements of the community, ranging from community composition and structure to the structure of individual canopy species. We show the vulnerability of the canopy shrubs to transformation as the accumulated influences of elephants alter community composition and structure. The pattern of transformation is similar to that caused by domestic herbivores, which leads us to predict that elephants will eventually bring about landscape-level degradation and a significant loss of biodiversity. While we expected the canopy species to show similar declining trends in structure, providing insight into the response of the community as a whole, we demonstrate an uneven distribution of impacts between constituent elements; most of the canopy dominants exhibited little change, resisting removal. This implies that these canopy dominants might not be useful indicators of community change in thickets, a pattern that is likely repeated among the canopy trees of savanna systems. Our findings suggest that predicting elephant impacts, and finding solutions to the so-called “elephant problem,” require a broader and more integrated understanding of the mechanisms driving the changes between elements of biodiversity at various spatial and temporal scales.
- Published
- 2014
- Full Text
- View/download PDF
37. Shift in black rhinoceros diet in the presence of elephant: evidence for competition?
- Author
-
Landman M, Schoeman DS, and Kerley GI
- Subjects
- Animals, Diet, Elephants physiology, Perissodactyla physiology
- Abstract
In African large herbivore assemblages, megaherbivores dominate the biomass and utilise the greatest share of available resources. Consequently, they are considered a separate trophic guild that structures the food niches of coexisting large herbivores. However, there exists little empirical evidence on how food resources are shared within this guild, and none for direct competition for food between megaherbivores. Using the histological analysis of faeces, we explore this phenomenon for African elephant Loxodonta africana and black rhinoceros Diceros bicornis in the Addo Elephant National Park, South Africa, where the accumulated impacts of elephant have reduced browse availability. Despite being unable to generalise beyond our study sites, our observations support the predictions of competition theory (as opposed to optimality theory) by showing (1) a clear seasonal separation in resource use between these megaherbivores that increased as resource availability declined, and (2) rhinoceros changed their selectivity in the absence of elephant (using an adjacent site) by expanding and shifting their diet along the grass-browse continuum, and in relation to availability. Although black rhinoceros are generally considered strict browsers, the most significant shift in diet occurred as rhinoceros increased their preferences for grasses in the presence of elephant. We speculate that the lack of specialised grazing adaptations may increase foraging costs in rhinoceros, through reduced harvest- and handling-efficiencies of grasses. In the short-term, this may be off-set by an enhanced tolerance for low quality food and by seasonally mobilising fat reserves; however, the long-term fitness consequences require further study. Our data suggest that managing elephant at high densities may compromise the foraging opportunities of coexisting browsers. This may be particularly important in small, fenced areas and overlapping preferred habitats where impacts intensify.
- Published
- 2013
- Full Text
- View/download PDF
38. Spatial access priority mapping (SAPM) with fishers: a quantitative GIS method for participatory planning.
- Author
-
Yates KL and Schoeman DS
- Subjects
- Conservation of Natural Resources, Humans, Fisheries methods, Geographic Information Systems
- Abstract
Spatial management tools, such as marine spatial planning and marine protected areas, are playing an increasingly important role in attempts to improve marine management and accommodate conflicting needs. Robust data are needed to inform decisions among different planning options, and early inclusion of stakeholder involvement is widely regarded as vital for success. One of the biggest stakeholder groups, and the most likely to be adversely impacted by spatial restrictions, is the fishing community. In order to take their priorities into account, planners need to understand spatial variation in their perceived value of the sea. Here a readily accessible, novel method for quantitatively mapping fishers' spatial access priorities is presented. Spatial access priority mapping, or SAPM, uses only basic functions of standard spreadsheet and GIS software. Unlike the use of remote-sensing data, SAPM actively engages fishers in participatory mapping, documenting rather than inferring their priorities. By so doing, SAPM also facilitates the gathering of other useful data, such as local ecological knowledge. The method was tested and validated in Northern Ireland, where over 100 fishers participated in a semi-structured questionnaire and mapping exercise. The response rate was excellent, 97%, demonstrating fishers' willingness to be involved. The resultant maps are easily accessible and instantly informative, providing a very clear visual indication of which areas are most important for the fishers. The maps also provide quantitative data, which can be used to analyse the relative impact of different management options on the fishing industry and can be incorporated into planning software, such as MARXAN, to ensure that conservation goals can be met at minimum negative impact to the industry. This research shows how spatial access priority mapping can facilitate the early engagement of fishers and the ready incorporation of their priorities into the decision-making process in a transparent, quantitative way.
- Published
- 2013
- Full Text
- View/download PDF
39. Beyond climate change attribution in conservation and ecological research.
- Author
-
Parmesan C, Burrows MT, Duarte CM, Poloczanska ES, Richardson AJ, Schoeman DS, and Singer MC
- Subjects
- Adaptation, Physiological, Animals, Butterflies physiology, Global Warming, Greenhouse Effect, Models, Theoretical, Research Design, Climate Change, Ecology methods, Research trends
- Abstract
There is increasing pressure from policymakers for ecologists to generate more detailed 'attribution' analyses aimed at quantitatively estimating relative contributions of different driving forces, including anthropogenic climate change (ACC), to observed biological changes. Here, we argue that this approach is not productive for ecological studies. Global meta-analyses of diverse species, regions and ecosystems have already given us 'very high confidence' [sensu Intergovernmental Panel on Climate Change (IPCC)] that ACC has impacted wild species in a general sense. Further, for well-studied species or systems, synthesis of experiments and models with long-term observations has given us similarly high confidence that they have been impacted by regional climate change (regardless of its cause). However, the role of greenhouse gases in driving these impacts has not been estimated quantitatively. Should this be an ecological research priority? We argue that development of quantitative ecological models for this purpose faces several impediments, particularly the existence of strong, non-additive interactions among different external factors. However, even with current understanding of impacts of global warming, there are myriad climate change adaptation options already developed in the literature that could be, and in fact are being, implemented now., (© 2013 John Wiley & Sons Ltd/CNRS.)
- Published
- 2013
- Full Text
- View/download PDF
40. Climate change and marine life.
- Author
-
Richardson AJ, Brown CJ, Brander K, Bruno JF, Buckley L, Burrows MT, Duarte CM, Halpern BS, Hoegh-Guldberg O, Holding J, Kappel CV, Kiessling W, Moore PJ, O'Connor MI, Pandolfi JM, Parmesan C, Schoeman DS, Schwing F, Sydeman WJ, and Poloczanska ES
- Subjects
- Data Collection, Data Interpretation, Statistical, Geography, Oceanography methods, Oceans and Seas, Time Factors, Climate Change, Ecosystem, Marine Biology methods, Marine Biology trends
- Abstract
A Marine Climate Impacts Workshop was held from 29 April to 3 May 2012 at the US National Center of Ecological Analysis and Synthesis in Santa Barbara. This workshop was the culmination of a series of six meetings over the past three years, which had brought together 25 experts in climate change ecology, analysis of large datasets, palaeontology, marine ecology and physical oceanography. Aims of these workshops were to produce a global synthesis of climate impacts on marine biota, to identify sensitive habitats and taxa, to inform the current Intergovernmental Panel on Climate Change (IPCC) process, and to strengthen research into ecological impacts of climate change.
- Published
- 2012
- Full Text
- View/download PDF
41. Understanding long-term variations in an elephant piosphere effect to manage impacts.
- Author
-
Landman M, Schoeman DS, Hall-Martin AJ, and Kerley GI
- Subjects
- Animals, Biodiversity, Drinking Water, Population Density, Water Supply, Ecosystem, Elephants
- Abstract
Surface water availability is a key driver of elephant impacts on biological diversity. Thus, understanding the spatio-temporal variations of these impacts in relation to water is critical to their management. However, elephant piosphere effects (i.e. the radial pattern of attenuating impact) are poorly described, with few long-term quantitative studies. Our understanding is further confounded by the complexity of systems with elephant (i.e. fenced, multiple water points, seasonal water availability, varying population densities) that likely limit the use of conceptual models to predict these impacts. Using 31 years of data on shrub structure in the succulent thickets of the Addo Elephant National Park, South Africa, we tested elephant effects at a single water point. Shrub structure showed a clear sigmoid response with distance from water, declining at both the upper and lower limits of sampling. Adjacent to water, this decline caused a roughly 300-m radial expansion of the grass-dominated habitats that replace shrub communities. Despite the clear relationship between shrub structure and ecological functioning in thicket, the extent of elephant effects varied between these features with distance from water. Moreover, these patterns co-varied with other confounding variables (e.g. the location of neighboring water points), which limits our ability to predict such effects in the absence of long-term data. We predict that elephant have the ability to cause severe transformation in succulent thicket habitats with abundant water supply and elevated elephant numbers. However, these piosphere effects are complex, suggesting that a more integrated understanding of elephant impacts on ecological heterogeneity may be required before water availability is used as a tool to manage impacts. We caution against the establishment of water points in novel succulent thicket habitats, and advocate a significant reduction in water provisioning at our study site, albeit with greater impacts at each water point.
- Published
- 2012
- Full Text
- View/download PDF
42. The pace of shifting climate in marine and terrestrial ecosystems.
- Author
-
Burrows MT, Schoeman DS, Buckley LB, Moore P, Poloczanska ES, Brander KM, Brown C, Bruno JF, Duarte CM, Halpern BS, Holding J, Kappel CV, Kiessling W, O'Connor MI, Pandolfi JM, Parmesan C, Schwing FB, Sydeman WJ, and Richardson AJ
- Subjects
- Biodiversity, Oceans and Seas, Seasons, Climate Change, Ecosystem
- Abstract
Climate change challenges organisms to adapt or move to track changes in environments in space and time. We used two measures of thermal shifts from analyses of global temperatures over the past 50 years to describe the pace of climate change that species should track: the velocity of climate change (geographic shifts of isotherms over time) and the shift in seasonal timing of temperatures. Both measures are higher in the ocean than on land at some latitudes, despite slower ocean warming. These indices give a complex mosaic of predicted range shifts and phenology changes that deviate from simple poleward migration and earlier springs or later falls. They also emphasize potential conservation concerns, because areas of high marine biodiversity often have greater velocities of climate change and seasonal shifts.
- Published
- 2011
- Full Text
- View/download PDF
43. Complex, dynamic combination of physical, chemical and nutritional variables controls spatio-temporal variation of sandy beach community structure.
- Author
-
Ortega Cisneros K, Smit AJ, Laudien J, and Schoeman DS
- Subjects
- Animals, Environmental Monitoring, Geography, Geologic Sediments chemistry, Inorganic Chemicals analysis, Multivariate Analysis, Oceans and Seas, Organic Chemicals analysis, Population Density, Population Dynamics, South Africa, Ecosystem, Invertebrates growth & development, Seasons, Seawater chemistry
- Abstract
Sandy beach ecological theory states that physical features of the beach control macrobenthic community structure on all but the most dissipative beaches. However, few studies have simultaneously evaluated the relative importance of physical, chemical and biological factors as potential explanatory variables for meso-scale spatio-temporal patterns of intertidal community structure in these systems. Here, we investigate macroinfaunal community structure of a micro-tidal sandy beach that is located on an oligotrophic subtropical coast and is influenced by seasonal estuarine input. We repeatedly sampled biological and environmental variables at a series of beach transects arranged at increasing distances from the estuary mouth. Sampling took place over a period of five months, corresponding with the transition between the dry and wet season. This allowed assessment of biological-physical relationships across chemical and nutritional gradients associated with a range of estuarine inputs. Physical, chemical, and biological response variables, as well as measures of community structure, showed significant spatio-temporal patterns. In general, bivariate relationships between biological and environmental variables were rare and weak. However, multivariate correlation approaches identified a variety of environmental variables (i.e., sampling session, the C∶N ratio of particulate organic matter, dissolved inorganic nutrient concentrations, various size fractions of photopigment concentrations, salinity and, to a lesser extent, beach width and sediment kurtosis) that either alone or combined provided significant explanatory power for spatio-temporal patterns of macroinfaunal community structure. Overall, these results showed that the macrobenthic community on Mtunzini Beach was not structured primarily by physical factors, but instead by a complex and dynamic blend of nutritional, chemical and physical drivers. This emphasises the need to recognise ocean-exposed sandy beaches as functional ecosystems in their own right.
- Published
- 2011
- Full Text
- View/download PDF
44. Give beach ecosystems their day in the sun.
- Author
-
Dugan JE, Defeo O, Jaramillo E, Jones AR, Lastra M, Nel R, Peterson CH, Scapini F, Schlacher T, and Schoeman DS
- Subjects
- Oceans and Seas, Climate Change, Ecosystem
- Published
- 2010
- Full Text
- View/download PDF
45. Climate impact on plankton ecosystems in the Northeast Atlantic.
- Author
-
Richardson AJ and Schoeman DS
- Subjects
- Animals, Atlantic Ocean, Fisheries, Fishes, Greenhouse Effect, Meta-Analysis as Topic, Population Dynamics, Seawater, Temperature, Climate, Copepoda growth & development, Ecosystem, Food Chain, Phytoplankton growth & development, Zooplankton growth & development
- Abstract
It is now widely accepted that global warming is occurring, yet its effects on the world's largest ecosystem, the marine pelagic realm, are largely unknown. We show that sea surface warming in the Northeast Atlantic is accompanied by increasing phytoplankton abundance in cooler regions and decreasing phytoplankton abundance in warmer regions. This impact propagates up the food web (bottom-up control) through copepod herbivores to zooplankton carnivores because of tight trophic coupling. Future warming is therefore likely to alter the spatial distribution of primary and secondary pelagic production, affecting ecosystem services and placing additional stress on already-depleted fish and mammal populations.
- Published
- 2004
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.