Landscape Ecology in the Marine Environment Erin Murphy

On a landscape ecology of a harlequin environment: the marine landscape (Jelinski, 2014) Marine landscape is a mosaic of resource and environmental patches Issues of heterogeneity, scale, patchiness, hierarchy and connectivity are critical in marine systems Goal: Make a case for the application of landscape ecology to study marine systems

Patchiness and structure in the marine landscape Both abiotic and biotic factors create patchiness in marine systems The transport of energy, resources and organisms through the fluid- medium is important for patch structure and configuration Abiotic features Biotic features Salinity Predator-prey interactions Temperature Primary producers Thermal refugia Spawning distribution Upwelling Foraging behaviors Hydrographic fronts Hydraulic flow

Landscape ecology in a marine context General absence of landscape ecology perspective in marine systems Marine Ecosystem Application of LE Example Benthic Explicit in several studies Algal accumulation on beaches Pelagic Few studies Reef fish assemblages Applied conservation Deemed critical by many Connectivity for MPAs

Landscapes and seascapes: Where’s the problem? “Landscape” terminology inherently seen as terrestrial unit Author response: Forman (1995) definition is applicable to marine systems Marine landscapes have unstable components which blur the linkage between physical and biological processes Author response: This is an issue of scale, but same principles hold true

Landscapes and seascapes: Where’s the problem? Open ocean systems are often viewed as homogenous Author response: Marine systems simply have different scales of importance. New technology will help. Concept of ecosystems has not been widely accepted. Marine systems have greater openness of boundaries Author response: Concept of relative boundedness is one way to understand the controls of ecosystem dynamics

Conclusion Potential for Landscape Ecology in marine systems has been discussed since Steele (1989) Need for cross-fertilization between marine and terrestrial ecology Calls for alignment have been largely unheeded. Landscape Ecology approach can have impactful implications in marine systems

Influence of landscape structure on reef fish assemblages Rikki Grober-Dunsmore, Thomas K. Frazer, James P. Beets, William J. Lindberg, Paul Zwick, Nicholas A. Funicelli 2007 An example of the landscape ecology approach for a pelagic system

Landscape ecology and coral reefs A landscape ecology approach has proven valuable for terrestrial land management Reefs are a complex mosaic of patches Can a landscape ecology approach be used for coral reef management?

Background Current understandings of reef fish assemblages are at small spatial scales Large-scale determinants of assemblages are desired by managers Understanding the relative importance of habitat features at different spatial scales is important for management.

Goals of this study This study looks at the utility of: landscape metrics, Individual habitat features, and fine-scale habitat variation for predicting reef fish assemblages.

Study area 20 sites were sampled, 14 in 1994 and 6 in 2001 Landscape features varied Coral cover, morphology, and depth were consistent 26 discrete habitat classes were aggregated into 9

Reef fish sampling Fish sampling: 8-20 “point” sample per reef

Habitat sampling 14 metrics Land-scape metric were calculated at 100m Ppmc and PCA were used Fine-scale: rugosity Multiple regression analyses

Results – Landscape Structure PCA: 4 dominant components of variation These components explained ~80% of variance Principal components explained few reef fish assemblage parameters Cumulative and mean species richness were marginally correlated with PC4

Reef fish assemblage structure Configuration was a poor predictor of assemblage structure Parameters were not correlated with reef size or habitat diversity Reef context was correlated with 13/30 parameters Areal seagrass coverage – species richness, and MIFs Areal reef coverage – adult piscivores Rugosity: only 5 parameters correlated Never the single explanatory variable

Discussion Parameter Predictor quality Discussion Reef Context Good Consistent with ecology of each group Matrix Likely even more in small reefs Principal components (composite index) Poor Difficult to interpret ecological meaning; may contain too much info Habitat Diversity (composite index) Definition of diversity may limit this Configuration measures Corroborated Pittman et al. (2004) Reef size May be consequence of scale Rugosity May be a ineffective measure of topo. complexity at whole reef scale

Key takeaways Challenge the effectiveness of generic landscape indices for developing protected areas at the scale of individual reefs Context matters, matrix matters Specific landscape features are associated with particular groups Some at larger scales than previously recognized Should consider fine- and landscape-scale features for management

Conclusion Overall there are clear benefits that could come from applying landscape ecology theory to marine ecosystems Challenges do exist that make application difficult Need better alignment of terrestrial and marine theory Need to strongly consider differences between the systems

Thank You Questions?