Urban impacts on tropical island streams: Some key aspects influencing ecosystem response

Ramírez, Alonso; Engman, Augustin C.; Rosas, Keysa G.; Pérez‐Reyes, Omar; Martinó-Cardona, Diana M.

doi:10.1007/s11252-011-0214-3

Cited by 59 publications

(37 citation statements)

References 52 publications

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“…Overhanging culverts mainly impacted on migratory species and species that lacked climbing ability. The impact of barriers on riverine species might affect species presence more significantly than pollution or habitat modification in tropical islands because diadromy is the most prevalent life‐history type (Hein et al., ; Ramírez, Engman, Rosas, Perez‐Reyes, & Martinó‐Cardona, ). In Fiji, over 98% of fish in rivers use saltwater habitats during their life cycle (Jenkins et al., ).…”

Section: Discussionmentioning

confidence: 99%

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

et al. 2017

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Anthropogenic disturbances particularly affect biodiversity in sensitive freshwater ecosystems by causing species loss. Thus, measuring the response of species to multiple disturbances is a key issue for conservation and environmental management. As it is not practical to assess the response of every species in a community, we compared the performance of trait and taxonomic-based groupings of species for their abilities to predict species loss in a threatened freshwater fish assemblage. Specifically, we examined responses of a Fijian freshwater fish assemblage to deforestation, placement of anthropogenic barriers (overhanging culverts) and the presence of introduced cichlids. Species grouped by traits showed more consistent responses to disturbances than taxonomic groups. In particular, species belonging to trait groups that were estuary associated favoured medium-to-hard substrate, while feeding specialists were highly likely to be absent in catchments with high deforestation and overhanging culverts. The presence of introduced cichlids (Oreochromis mossambicus and O. niloticus) had a smaller effect than deforestation and barriers, but was negatively associated with species richness of diadromous species with climbing ability and positively associated with presences of some piscivores. The trait groups also revealed that detritivores, species favouring soft substrate, and those with a broad dietary range were less sensitive to anthropogenic disturbances. Our study indicates that using traits to predict species loss from disturbed environments can aid in detecting the responses of rare species to disturbance. In addition, we provided a method to estimate the consistency of species’ responses to disturbance. This study may ultimately help managers identify the most effective actions for conserving sensitive species that are seldom recorded in surveys

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Section: Discussionmentioning

confidence: 99%

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

et al. 2017

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“…A strong relationship between watershed land cover and stream insect biota is well established (Chinnayakanahalli et al 2011;Chadwick et al 2012;Vander Laan et al 2013). Although previous studies of Caribbean urban streams have evaluated species responses of aquatic insects to environmental changes (e.g., de Jesús-Crespo and Ramírez 2011; Ramírez et al 2012), none have focused on freshwater decapod community structure or their roles in urban stream ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Comparison of decapod communities across an urban-forest land use gradient in Puerto Rican streams

2015

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Urbanization influences a range of factors related to stream health, including the hydrologic regime, water quality, and riparian conditions that lead to negative effects on terrestrial and aquatic ecosystems. However, impacts on freshwater decapods from urbanization of tropical streams have not been reported. We hypothesized that changes in decapod communities in watersheds with different levels of urbanization are related to changes in physical stream habitats caused by different land uses and their effects on water discharge. The impacts of land use on the physico-chemical characteristics of streams and freshwater decapod communities were evaluated in three watersheds characterized by low, moderate and highintensities of urbanization in Puerto Rico. For the low and moderately developed urban watersheds, decapod species richness ranged from 10 to 11 species; the highly urbanized watershed only had 4 species. Macrobrachium faustinum and Xiphocaris elongata were the most ubiquitously species and were found in all watersheds. Multivariable analysis of physical characteristics and densities of the decapod families resulted in one axis that explained 80 % of the total variation among the watersheds and was correlated with stream discharge. The effect of discharge is likely a result of frequent high flows that sustain habitats with high concentrations of dissolved oxygen and low concentrations of pollutants. An increase in physicochemical parameters were observed from the LUW to the HUW. These results indicate that the decapod communities were most likely influenced by land use and environmental conditions that affected erosional aspects related to water discharge and water quality in the highly impacted watersheds.

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“…The productivity of estuarine and coastal fisheries that target diadromous species is strongly affected by river freshwater discharge (Gillson 2011;Meynecke & Lee 2011;Gillson, Suthers & Scandol 2012). Land-use changes such as urbanization or agriculture has modified or polluted important habitats along streams (Hein et al 2011;Ramírez et al 2012). Finally, invasive species and increased fishing pressure can impact populations in freshwater ecosystems (McDowall 2006).…”

Section: Threats To Diadromous Fishmentioning

confidence: 99%

“…Diadromy (especially amphidromy) is one of the dominant life history forms in riverine species including fish, crustaceans and mollusks in oceanic islands (Greathouse, Pringle & Holmquist 2006;McDowall 2007b;McDowall 2007a;Ramírez et al 2012). In Fiji, over 98% of riverine fishes use saltwater habitats during their life cycle niloticus) are considered as major threats to native riverine fish communities in Fiji Jenkins & Jupiter 2011;Jupiter et al 2012).…”

Section: Diadromous Fish In Oceaniamentioning

confidence: 99%

“…The impact of barriers on riverine species might affect species presence more significantly than pollution or habitat modification in tropical islands because diadromy is the most prevalent life history type (Hein et al, 2011;Ramírez et al, 2012). In Fiji, over 98% of fish in rivers use saltwater habitats during their life cycle .…”

Section: Schismatogobius Vitiensis and Mesopristes Kneri) While Thementioning

confidence: 99%

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Conserving migratory species under human impacts and climate change

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Migratory species use multiple habitats types and ecosystems to complete their life cycles, which exposes them to multiple human-caused stressors along their migratory routes. Overexploitation, habitat degradation, invasive species and connectivity loss have contributed to the decrease of migratory fishes globally in particular diadromous fishes that migrate between marine and freshwater systems. Therefore, understanding the joint impacts from anthropogenic disturbances and climate change on different habitats (e.g., both feeding and spawning grounds) and habitat connectivity (e.g., migration routes) is important for conserving migratory fish.Management will be most effective when management scales match ecological scales. This is particularly important for conserving migratory species, because of the requirement of multiple connected habitats that may cross local management boundaries. The main goals of this Ph.D. thesis are to quantify the impacts of multiple stressors on migratory fish species and prioritize management actions for conserving populations (chapters 2 & 3), species (chapter 4), and communities (chapter 5).A central challenge for managing diadromous fishes (species that migrate between freshwater and saltwater ecosystems) is to quantify increases in population persistence from actions that improve connectivity or reduce fishing mortality. In chapter 2, I used a population dynamic model and fish movement data to predict the interactive impacts of fishing pressure and connectivity loss by human modification of river flows on Australian bass Percalates novemaculeata. Then, in chapter 3, the monetary cost of management actions which included seasonal closures and restoring connectivity, were included in the model to find the most cost-effective way to conserve this fish population. The results reveal that the cost-effectiveness of management actions may vary with river flow and fishing pressure before implementing management actions, and implementation times. The spatiotemporal dynamics of how fish species and key resource users (i.e., anglers) respond to management actions can influence the effectiveness of management strategies. Flexible management plans and increased cooperation between water and fishery managers can be used to achieve the most effective balance between conserving migratory fish populations and minimising cost.Migratory species are particularly vulnerable to climate change as they occupy different ecosystems, as well as transitional habitat which are all impacted by climate change differently.Anthropogenic barriers can further reduce the ability of species to respond to a shifting climate. In ii chapter 4, I assessed the impact of climate change on the distribution of a migratory fish species, Australian grayling Prototroctes maraena, and how it affected priorities for restoring connectivity. I found climate change moves at different rates in marine and freshwater systems, decoupling the habitats used by grayling. In addition, the changing spatial distribution of suitable ...

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Urban impacts on tropical island streams: Some key aspects influencing ecosystem response

Cited by 59 publications

References 52 publications

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

Comparison of decapod communities across an urban-forest land use gradient in Puerto Rican streams

Conserving migratory species under human impacts and climate change

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