Habitat complexity: approaches and future directions

Kovalenko, Katya E.; Thomaz, Sidinei Magela; Warfe, Danielle M.

doi:10.1007/s10750-011-0974-z

Cited by 445 publications

(389 citation statements)

References 146 publications

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“…Structural complexity plays an important role in structuring biotic assemblages and in maintaining biodiversity of benthic marine ecosystems [1]. The structure of intertidal and subtidal rocky reefs has been shown to be a major factor in the dynamics of resident organisms [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…The structure of intertidal and subtidal rocky reefs has been shown to be a major factor in the dynamics of resident organisms [2][3][4]. Biogenic habitats provided by organisms such as oysters, mangroves, seagrass, macroalgae, and corals are critical to the integrity of their resident assemblages ( [1] and references therein). This is well studied in coral reef habitats where complexity is strongly related to important aspects of ecosystem function and service including coral cover, grazing pressure, fish density and biomass, and even tourism and shoreline protection [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Accuracy and Precision of Habitat Structural Complexity Metrics Derived from Underwater Photogrammetry

et al. 2015

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Abstract:In tropical reef ecosystems corals are the key habitat builders providing most ecosystem structure, which influences coral reef biodiversity and resilience. Remote sensing applications have progressed significantly and photogrammetry together with application of structure from motion software is emerging as a leading technique to create three-dimensional (3D) models of corals and reefs from which biophysical properties of structural complexity can be quantified. This enables the addressing of a range of important marine research questions, such as what the role of habitat complexity is in driving key ecological processes (i.e., foraging). Yet, it is essential to assess the accuracy and precision of photogrammetric measurements to support their application in mapping, monitoring and quantifying coral reef form and structure. This study evaluated the precision (by repeated modeling) and accuracy (by comparison with laser reference models) of geometry and structural complexity metrics derived from photogrammetric 3D models of marine benthic habitat at two ecologically relevant spatial extents; individual coral colonies of a range of common morphologies and patches of reef area of 100s of square metres. Surface rugosity measurements were generally precise across all morphologies and spatial extents with average differences in the geometry of replicate models of 1-6 mm for coral colonies and 25 mm for the reef area. Precision decreased with complexity of the coral morphology, with metrics for small massive corals being the most precise (1% coefficient of variation (CV) in surface rugosity) and metrics for bottlebrush corals being the least precise (10% CV in surface rugosity). There was no indication however that precision was related to complexity for the patch-scale modelling. The 3D geometry of coral models differed by only 1-3 mm from laser reference models. However, high spatial variation in these differences around the model led to a consistent underestimation of surface rugosity values for all morphs of between 8% and 37%. This study highlights the utility of several off-the-shelf photogrammetry tools for the measurement of structural complexity across a range of scales relevant to ecologist and managers. It also provides important information on the accuracy and precision of these systems which should allow for their targeted use by non-experts in computer vision within these contexts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Accuracy and Precision of Habitat Structural Complexity Metrics Derived from Underwater Photogrammetry

et al. 2015

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“…For instance, fish abundance and diversity was higher in stream pool habitats with wood, possibly because of increased resource availability and protection from predators (Wright and Flecker 2004). As with resource pulses though, we have a relatively limited mechanistic understanding of how PHS shapes ecosystems (Kovalenko et al 2012, except see Cardinale et al 2002) including how it influences the movement of organisms through the environment, a key ecological process (Gaines and Bertness 1993, Bowler and Benton 2005, Kuefler et al 2010. For example, PHS may modify drift, or the downstream movement of invertebrates in the water column (Benke et al 1986).…”

Section: Introductionmentioning

confidence: 99%

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

et al. 2014

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An experiment and a mark‐recapture field study of juvenile coho salmon (Oncorhynchus kisutch) were conducted to identify controls of key energy flow chains in river food webs. In the small‐scale experiment, we investigated the individual and interactive effects of physical habitat structure (PHS) as small wood and resource availability (tissue of adult Chinook salmon, O. tshawytscha) on nutrients, algae, invertebrates, and fish predators including juvenile coho. In the field, we quantified the effects of natural variation in prey availability (invertebrate drift biomass), PHS (wood), and local fish density on summer growth of juvenile coho across multiple stream reaches. Adding salmon tissue to experimental channels resulted in strong bottom‐up effects on select invertebrates including increased population biomass of chironomids and baetids, the numerically dominant invertebrates, and faster growth of juvenile coho. We link the enhanced growth of coho to chironomid productivity: for instance, adult chironomid flux was 4.3× higher and coho consumption of these animals 3× higher in salmon‐subsidized channels. PHS in experimental channels was associated with reduced algal biomass, potentially in response to increased invertebrate consumption, and invertebrate flux or export. The field study revealed coho growth was negatively related to PHS and total fish density and positively related to Diptera drift biomass; however, the effects of fish density and drift biomass on coho growth were relatively weak. The field study also indicated that prey resource availability and coho growth were associated with differences in canopy cover, with prey biomass and coho growth 2–4× higher in reaches receiving more sunlight. As in the experiment, coho in natural stream reaches predominantly fed on adult chironomids and other Diptera, indicating that these taxa and life‐stages are a key link between the benthic food web and mobile vertebrate predators. Our study showed that bottom‐up processes initiated by salmon subsidies and possibly light flux determined key trophic interactions in the Cedar River food web. Moreover, we speculate that PHS may modify some of these interactions indirectly through its effects on the movement of organisms through the environment.

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“…In this study, we examined its effects on social network structure and explored how different levels of complexity affect population processes relevant to social structure and individual fitness. Habitat complexity has been defined in many ways, but generally refers to the complexity of physical or topographic structure in the environment (Kovalenko, Thomaz, & Warfe, 2012). Increased habitat complexity may benefit individuals if it, for instance, reduces predator effectiveness (Warfe & Barmuta, 2004), improves escape behaviour from predators (Jensen, Gray, & Hurst, 2003) or reduces male e male competition for females (Myhre, Forsgren, & Amundsen, 2013).…”

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confidence: 99%

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

et al. 2016

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Social structure is a fundamental component of a population that drives ecological and evolutionary processes ranging from parasite transmission to sexual selection. Nevertheless, we have much to learn about factors that explain variation in social structure. We used advances in biologging and social network analysis to experimentally test how the local habitat, and specifically habitat complexity, modulates social structure at different levels in wild populations. Sleepy lizards, Tiliqua rugosa, establish nonrandom social networks that are characterized by avoidance of some neighbours and frequent interactions with one opposite-sex individual. Using synchronous GPS locations of all adult lizards, we constructed social networks based on spatial proximity of individuals. We increased habitat structural complexity in two study populations by adding 100 short fences across the landscape. We then compared the resulting movement behaviour and social structure between these populations and two unmanipulated populations. Social connectivity (network density) and social stability, measured at weekly intervals, were greater in populations with increased habitat structural complexity. The level of agonistic interaction (quantified as scale damage) was also higher, indicating a fitness cost of greater social connectivity. However, some network parameters were unaffected by increased complexity, including disassortative mixing by sex, and at the individual level, social differentiation among associates (coefficient of variation of edge weights) and maximal interaction frequencies (maximal edge weight). This suggests divergent effects of changed ecological conditions on individual association behaviour compared to the resulting social structure of the population. Our results contrast with those from studies of more gregarious species, in which higher structural complexity in the environment relaxed the social connectivity. This shows that the response to altered ecological conditions can differ fundamentally between species or between populations, and we suggest that it depends on their tendency for gregarious behaviour.

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Habitat complexity: approaches and future directions

Cited by 445 publications

References 146 publications

Accuracy and Precision of Habitat Structural Complexity Metrics Derived from Underwater Photogrammetry

Accuracy and Precision of Habitat Structural Complexity Metrics Derived from Underwater Photogrammetry

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

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