What Is Seascape Ecology? Seascapes

NRS 534 Term Paper BJC Fuller / Advances in seascape ecology: applying landscape metrics to marine systems 1(5)

NEWS & VIEWS

What is seascape ecology? seascapes. This newest branch of landscape ecology treats the physical characteristics of marine Landscape ecology is a relatively new, multidisci- environments, including geographic and chemical plinary field which studies the relationship properties, as fundamentally landscape-like between ecological functions and spatial patterns patterns which can be correlated with the ecology, (Boström et al. 2012, Pittman et al. 2011, Wedding life-history, and biodiversity of species in those et al. 2011), and was primarily developed to ecosystems. inform management practices in terrestrial The complex geographic heterogeneity that systems (Pittman et al. 2011). Several important exists on land does not end at the water’s edge; tools, models, and methods of analysis have geophysical processes give rise to incredibly emerged which advance our understanding of the diverse coastal environments which support rich influence of geographic heterogeneity on the species assemblages in both familiar and unique health and sustainability of ecosystems on several ways. We know that aquatic environments offer scales (Pittman et al. 2011, Wedding et al. 2011). special mechanisms for enhancing patch connec- Generally, these metrics assess three fundamental tivity and maintaining community structure, and landscape properties: 1) composition, the diversity these factors are crucial for sustaining the ecologi- of patch types; 2) configuration, the arrangement cal integrity of these systems from multiple of those patch types; 3) and fractal dimension, the perspectives. Some of the most commonly complexity of that arrangement (Wedding et al. recognized marine spatial patters include the 2011). patch mosaics of mangroves, coral reefs, seagrass While these tools have been developed for beds, and tidal marshes, and the zonation of rocky and applied in terrestrial systems for nearly 50 shore and salt marsh biota (Pittman et al. 2011, years (Pittman et al. 2011), their use in describing Boström et al. 2012). Additionally, seascapes may spatial patterns in marine contexts has only not necessarily refer to any particular physical recently emerged, prompting the analogous term geography of the underwater landscape, but can

Ecol Fragmented Landscapes / April 2013 © 2013 (REV 118) 20130429 NRS 534 Term Paper BJC Fuller / Advances in seascape ecology: applying landscape metrics to marine systems 2(5) also be used to describe variation in chemical 2012, Berkström et al. 2012, Moberg & Rönnbäck composition throughout the water column. These 2003). These habitats provide a wonderful chemical ‘landscapes’ play hugely influential roles opportunity to assess correlations between flora, in the ecology of pelagic organisms, some of fauna, and the physical structure of the reef. which never encounter benthic geography. For Because of their incredible biodiversity, it seems example, Yu et al. (2011) studied the correlation fundamental that we understand how abiotic between the pH ‘landscape’, or what they refer to patterns influence species distribution throughout as the “ocean acidification seascape”, of nearshore reefs, which could allow us to break down the waters off California and the calcification of ecological complexity of these systems and have urchin larvae. enormous implications for the management of Most fascinating of all, though, is the applica- reefs worldwide. tion of landscape metrics which define pelagic Mumby (2006) attempted to accomplish some distributions of biota as seascapes themselves. of these goals by correlating the availability of Mitchell et al. (2008) described complex spatial mangrove nursery habitats with the health of adult arrangements of phytoplankton in the water reef fish, and then translating these results into column this way. These biological ‘patches’ algorithms that inform management practices. influence ecological functions, community The algorithms are fundamentally landscape- dynamics, and biodiversity in much the same way ecology-derived metrics, and assess the spatial as do geographic landscapes and seascapes, and distribution of Caribbean mangroves that provide they are, in turn, influenced by physical parame- high-quality habitat for juvenile fish, the connec- ters like turbulence. Phytoplankton patches don’t tivity between nursery sites and adult reef habitat, last long, only on the order of 100 to 1000 the relative importance of mangroves in providing seconds, but nonetheless they are distinctive nursery habitats for key reefs, and those man- enough to allow conceptual modeling of their groves which are of highest priority for restora- distribution, which has implications for determin- tion. These algorithms are all important in ing grazing efficiency and taxonomic diversity of understanding the affect of mangrove-reef spatial predatory species. It also emphasizes the concept relationships on reef community structure and of scale in the context of time in addition to space; biological sustainability, and operate in much the these biological seascapes might not be obvious at same way as similar metrics (like connectivity) do large timescales, but become readily apparent in terrestrial systems. when that scale is narrowed appropriately. This is Most recently, Olds et al. (2012) looked spe- probably the case with other dynamic mosaics, cifically at the correlation between mangrove-reef such as chemical seascapes. It should be noted, connectivity and reef complexity. They describe though, that no landscape (terrestrial or marine) is coral reefs as “mosaics of seemingly disjointed perfectly static; appreciating the lifespan of [habitats] that are functionally connected by the mosaics is critical in recognizing spatial patterns movement and dispersal of organisms”, heighten- which might be masked by assuming inappropri- ing the ecological parallels that exist between ate timescales. terrestrial and marine systems, and thus justifying the application of traditional landscape metrics in Coral reef connectivity and management aquatic environments. Using a combination of field surveys and satellite imagery, benthic habitat From the plethora of studies concerning marine classifications (including coral reefs, mangroves, ecology, we know that aquatic biota is indeed seagrass beds) were identified, and five spatial responsive to pelagic and benthic seascapes; by pattern metrics were used to quantify connectivity comparison, though, little has been done to assess between patches. They specifically highlight the these relationships in the way that landscape importance of scaling so that results are meaning- ecology has done for terrestrial systems (Boström ful and appropriate to the particular species of et al. 2012). However, several studies have used interest. These methods and concerns exactly these metrics to analyze aspects of coral reef eco- mirror the approach of traditional landscape spatial relationships (Mumby 2006, Olds et al.

Ecol Fragmented Landscapes / April 2013 © 2013 (REV 118) 20130429 NRS 534 Term Paper BJC Fuller / Advances in seascape ecology: applying landscape metrics to marine systems 3(5) ecology, reinforcing the universality of basic appropriate patch types in which to apply those ecological norms across all ecosystems. techniques. Patch connectivity, of course, is an In broader terms, Berkström et al (2012) de- integral part of the tropical seascape which must scribe coral reefs as part of a more comprehensive be considered for these techniques to be success- network of patches, including mangroves and ful, especially when replacing ecosystem services seagrass beds, which they call “the tropical with technological substitutes. The Moberg & seascape”. In their extensive review of ecological Rönnbäck (2003) study emphasizes the im- connectivity in tropical seascapes, they find that portance of recognizing seascapes in developing the role of migrating fish in providing this management frameworks which foster eco- connectivity is not well-understood through any friendly technology and promote the resilience of particular study. However, through their assess- both ecological communities and the societies that ment of what little has been learned on the topic, depend on them. it is clear that these fish probably perform a number of ecologically important functions and Future considerations should be studied more heavily in the future. They also draw conclusions about the importance The application of landscape ecology to marine of understanding connectivity throughout the ecosystems seems obvious, necessary, and tropical seascape in the context of reserve design relatively seamless. For each terrestrial process and placement; while coral reefs are often the assessed by landscape ecology, there is likely an highest priority in determining the location of analogous marine process which can be assessed marine protected areas (MPAs), interlinked similarly. The future seems bright for this patches like mangrove and seagrass beds are rarely emerging field, which lies arguably at the cross- included. By appreciating the role of connectivity roads of landscape and marine ecology. Metrics between these patches in collectively maintaining have already been applied to map ecosystem them, MPAs might be expanded to include processes like benthic production, turbidity, and habitats which support reefs via these important denitrification, which advance our understanding biotic and abiotic pathways; if the entire network of the functional value of coastal environments is not protected, MPAs will have little chance of across large areas (Eyre & Maher 2011). The effectively maintaining high-priority patches. study of sedimentary seascapes and the role of These metrics can also answer a number of benthic invertebrates which modify those mosaics important non-MPA-related questions pertaining (termed ‘ecosystem engineers’) is also emerging, to human interaction with the tropical seascape. and is important in extending seascape ecology on Moberg & Rönnbäck (2003) investigated coastal and into the seabed. New technology will allow anthropogenic pressures on the tropical seascape us to study these systems at greater and greater in order to address the limits of technological depths. Mathematical modeling of subterranean substitutes for ecosystem services (which they biological-geological interactions has already exemplify as artificial reefs, artificial seawalls, begun, and may result in new modeling methods aquaculture in mangroves, etc.) and ways in which that could eventually be applied to other seascapes ecosystem restoration can not only rejuvenate and terrestrial systems as well (Meadows et al. these services but simultaneously result in a more 2012). Other studies have investigated the resilient ecosystem. Some patch types, such as influence of seascapes on predation in coastal mangroves and seagrass beds, are more success- environments (Roliv & Schiel 2006), allowing us fully restored than complex habitats like coral to understand the dependency of these interac- reefs. By understanding the interaction between tions on geographic spatial patterns. This might geographic heterogeneity (some of which we cause us to revise previous models of predator- create ourselves) and the health of the biotic prey interactions to include metrics that consider communities which are supported by it, we can patch composition, configuration, and fractal begin to predict the impact various management dimension. techniques will have in a given ecosystem, which Since many useful tools have already been may subsequently help us determine the most developed through the study of landscape ecolo-

Ecol Fragmented Landscapes / April 2013 © 2013 (REV 118) 20130429 NRS 534 Term Paper BJC Fuller / Advances in seascape ecology: applying landscape metrics to marine systems 4(5) gy, and can be applied, without much modifica- background to the emerging field of seascape ecology and was critical in cross-referencing several key pieces of information. The tion, to marine environments, it is likely that variety of topics covered (e.g. the importance of scale; effects of seascape ecology will advance to an equal or near- patch size, edge, and fragmentation; geomorphology in salt equal state with landscape ecology relatively marshes; connectivity in coral reefs and mangroves) make it a lengthy paper, but numerous tables, graphs, and maps help quickly. As is the case with most offshoots of illustrate the main points more quickly. However, a comprehen- well-established fields, tools developed specifically sive read is a must if the actual methods and application of for seascape ecology will most likely help advance landscape metrics used to generate the data are to be understood. landscape ecology as well. The studies examined Eyre BD, Maher D. 2011. Mapping ecosystem processes and here point out a number of important considera- function across shallow seascapes. Cont Shelf Res 31:S162-S172 tions that apply to all eco-spatial analysis. The  This paper exemplified the power of using landscape metrics potential of seascape ecology in complementing to map coastal ecosystem functions over various scales in various habitats. This information can then be used to identify conserva- biological oceanography and marine ecology, as tion ‘hotspots’ and determine areas of high and low value to the well as informing ecosystem-based management overall health of the ecosystem. This particular study focused on practices, seems timely and powerful, and is mapping lagoons and river estuaries in Australia. In addition to maps, the data can be summarized using innovative diagrams, perhaps the missing link in solving many of the which provide a visual way to quickly compare the value of marine ecological problems facing the scientific, functions across different habitat classifications. The paper is not policy, and management communities today. a difficult read, and any text which might need clarification can usually be understood by studying the figures.

Meadows PS, Meadows A, Murray JMH. 2012. Biological modifiers of marine benthic seascapes: their role as ecosystem engineers. Geomorphology 157-158:31-48  This article reviews research on the role of marine benthic organisms in modifying the seabed seascape. The study introduc- es the idea of advanced mathematical modeling of this system, a concept which could be applied to other seascape/landscape Berkström C, Gullström M, Lindborg R, Mwandya AW, Yahya SAS, systems. It also discusses the importance of looking at the fossil Kautsky N, Nyström M. 2012. Exploring ‘knowns’ and ‘un- record in determining the interaction of biological and geological knowns’ in tropical seascape connectivity with insights from East processes that contributed to the formation of present seabed African coral reefs. Estuar Coast Shelf S 107:1-21 seascapes and sediment composition. Key points in the paper are  This is a very comprehensive review of literature on the summarized in flow charts and diagrams, which are incredibly connectivity between coral reefs and supporting habitats like useful in generalizing conclusions drawn from analysis conducted mangroves and seagrass beds, with a focus on ecosystems in East on the species level. Their review is long and in-depth, and given Africa. They refer to the mosaic of these patches as “the tropical the density of the paper their conclusions did not seem as compre- seascape” and find that the connectivity between patches is hensive as it could have been. relatively poorly understood, especially with regard to the role of migratory fish as biological linkers. The actual article itself is Mitchell JG, Yamazaki H, Seuront L, Wolk F, Li H. 2008. Phytoplank- relatively brief, but paper includes extremely comprehensive ton patch patterns: Seascape anatomy in a turbulent ocean. J tables summarizing the documentation of fish species around Marine Syst 69:247-253 Zanzibar Island off Tanzania, and studies on fish connectivity  This is a fascinating study which applied seascape ecology between various habitats. They emphasize that it is important to metrics to describe patterns of phytoplankton patches. These approach environmental management from the perspective of patches arise partly in response to turbulence and eddy currents, seascapes, as opposed to habitats, since this approach takes into and form distinctive asymmetric patches with regular distribution. account the connectivity and relative importance of each patch The study was most interesting for its recognition of biological within the ecosystem mosaic. There is a lot of information in this distributions as seascapes in and of themselves, which seems to be article, but identification of main points was not difficult. It seems a relatively new concept. It also emphasizes the importance of that much of the detailed data would be useful in subsequent appreciating timescales when applying landscape metrics and papers focusing specifically on the ecology and biology of fishes in recognizing seascapes; otherwise certain mosaics might not be the Zanzibar region, but not in drawing general conclusions about recognized as seascapes if inappropriate timescales are used. The connectivity and seascapes in a more global sense. study used in situ fluorescence to identify plankton patches and correlated these with measures of physical oceanographic Boström C, Pittman SJ, Simenstad C, Kneib RT. 2011. Seascape parameters such as salinity and temperature. Some graphs were ecology of coastal benthic habitats: advances, gaps, and chal- difficult to comprehend; however the conceptual 2D distributions lenges. Mar Ecol Prog Ser 427:191-217 were very fascinating.  This article appeared in a Marine Ecology Progress Series theme section focusing on seascape ecology, a special edition Moberg F, Rönnbäck P. 2003. Ecosystem services of the tropical edited in part by the authors of Pittman et al. (2011). It is a highly seascape: interactions, substitutions and restoration. Ocean useful review article that highlights both areas of progress and of Coast Manage 46:27-46 need in the field, and evaluates the response of biota to fragmen-  This is a rather elegant article which assesses the tropical tation in various marine habitats. Along with Pittman et al. (2011) seascape in attempt to answer two fundamental management and Wedding et al. (2011), this article provides some wonderful questions: to what extent can technological substitutes for

ecosystem services be effective, and how can ecosystem restora- Rilov G, Schiel DR. 2006. Seascape-dependent subtital-intertidal tion result in both the return of those services and the resilience of trophic linkages. Ecol 87:731-744 the system to future disturbances. It is an important article for  This paper looked at settlement, predation, and trophic understanding the potential of seascape ecology in a manage- linkages between fish, crab, and mussel species in coastal envi- ment context, and does a good job of providing background ronments around New Zealand. The goal was to understand the information about each patch type as well as examples of man- relationship between these predator-prey interactions and the agement projects that have been successful because of their seascape itself, with considerations for scale. It was primarily integration within the tropical seascape patch mosaic. interesting for this reason, since the study of predator-prey interactions often acknowledge the influence of geographic Mumby, PJ. 2006. Connectivity of reef fish between mangroves and heterogeneity, but only in the context of accounting for errors in coral reefs: Algorithms for the design of marine reserves at modeling. The application of seascape ecology in understanding seascape scales. Biol Conserv 128:215-222 predator-prey interactions could have huge implications for  This study synthesized data on mangrove nurseries and the revising models and explaining and removing errors in the health of adult reef fish to develop four algorithms which inform analysis. The paper is heavy on statistics, which makes under- management efforts in mangrove habitats. The study was fairly standing the extent of the significance of interactions difficult comprehensive, using landscape metrics to assess connectivity and without a working knowledge of multivariate ANOVA. Trophic patch importance throughout the Carribean. Information was webs help illustrate these interactions in the context of seascapes well-organized and summarized in both tabular and graphic when statistical specifics aren’t necessary for conveying overall formats, which made it easier to identify the overall results and conclusions, which make the paper a bit more palatable. implications of the study. This article was crucial for highlighting the application of seascape ecology in directing management Wedding LM, Lepczyk CA, Pittman SJ, Friedlander AM, Jorgensen S. practices, since this area of seascape ecology is as of yet underde- 2011. Quantifying seascape structure: extending terrestrial veloped. spatial pattern metrics to the marine realm. Mar Ecol Prog Ser 427:219-232 Olds AD, Connolly RM, Pitt KA, Maxwell PS. 2012. Primacy of  This is a very comprehensive review article that appeared in a seascape connectivity effects in structuring coral reef fish Marine Ecology Progress Series theme section focusing on sea- assemblages. Mar Ecol Prog Ser 426:191-203 scape ecology, which was edited in part by the authors of Pitmann  This study focused specifically on using metrics to assess the et al. (2011). It gives a general background about the origins of connectivity of mangroves and coral reefs, and the role of such seascape ecology, and covers advancements in some important connectivity in maintaining healthy adult reef fish assemblages. topics including 2D and 3D seascape applications, the influence of This was an important article in providing an in-depth look at how scale, analytical techniques, and general problems encountered. these metrics can be applied to marine connectivity, and built Diagrammatical representations of analytical problems and upon Mumby (2006). Reading was not terribly dense, but required factors that influence the accuracy of seascape metrics help some special knowledge of reef fish assemblages and coral illustrate the main points made in what is otherwise a straight- reef/mangrove ecology in order to fully appreciate the results. forward but fairly dense read. Along with Pittman et al. (2011) and Boström et al. (2011), this article provides a nice overview of Pittman SJ, Kneib RT, Simenstad CA. 2011. Practicing coastal the advancements in seascape ecology and gives suggestions for seascape ecology. Mar Ecol Prog Ser 427: 187-190 future directions. Cross-referencing between these three articles  This is a highly useful review article that appeared as the lead proved highly useful. paper in a Marine Ecology Progress Series theme section focusing on seascape ecology. The authors were also the editors of the Yu PC, Matson PG, Martz TR, Hofmann GE. 2011. The ocean section, along with Ivan Nagelkerken, professor at The University acidification seascape and its relationship to the performance of of Adelaide in Australia. It discusses the emergence of seascape calcifying marine invertebrates: Laboratory experiments on the ecology as a subset of marine ecology, highlights various examples development of urchin larvae framed by environmentally- of marine spatial patterns, and points to some important direc- relevant pCO2/pH. J Exp Mar Biol Ecol 400:288-295 tions for the future study of seascape ecology. This was a perfect  This study looks at the relationship between pH ‘landscapes’, article to provide some necessary background about the develop- or what they refer to as the “ocean acidification seascape”, and ment of seascape ecology and the generally application of the ability of urchin larvae to calcify their exoskeleton. This paper landscape metrics to marine systems. Likewise, it seemed to serve was fascinating for its treatment of seascapes in a chemical, as as an introduction to the remainder of the theme section, which opposed to geographic, context, which was especially enlighten- made it easier to relate subsequent articles to each other ing. This invites a much broader perspective on the application of throughout the research process. the term seascape, and perhaps ushers in a new vein of seascape ecology that can be applied to wholly pelagic organisms that never encounter any sort of physical landscape.