Climate change and multiple stressors in small tropical streams

Taniwaki, Ricardo Hideo; Piggott, Jeremy J.; Ferraz, Sílvio; Matthaei, Christoph D.

doi:10.1007/s10750-016-2907-3

Cited by 65 publications

(51 citation statements)

References 122 publications

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“…Al‐Shami et al., ; Tonkin, Arimoro, & Haase, ). Although these systems are among the most diverse on earth, they are highly threatened by a broad suite of stressors (Dudgeon et al., ; Strayer & Dudgeon, ; Taniwaki, Piggott, Ferraz, & Matthaei, ). The effects of human activities on tropical streams are poorly understood and the pace of stream deterioration exceeds the pace of scientific research to understand ecosystem responses (Ramírez, Pringle, & Wantzen, ).…”

Section: Introductionmentioning

confidence: 99%

Landscape variables influence taxonomic and trait composition of insect assemblages in Neotropical savanna streams

2017

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Summary Stream invertebrate assemblages are structured by environmental factors acting at multiple spatial scales. Identifying the spatial scale that most influences the species–environment relationships is a major goal of community ecology. We evaluated the importance of catchment and site scales and associated environmental variables in shaping Ephemeroptera, Plecoptera and Trichoptera (EPT) assemblages in Neotropical savanna headwater streams. Sampling sites were associated with 20 catchment‐scale variables that depicted land cover and land use as well as natural geophysical variables such as altitude and climate. Site‐scale habitat was characterised by 55 variables that described habitat hydromorphology, substrate, flow, canopy, in‐stream cover and water quality. EPT traits were assessed using 28 categories of 7 biological traits, which represented the best available current knowledge for EPT in Neotropical savanna streams. We analysed the relationships between the catchment‐ and site‐scale habitat variables and the taxonomic and trait composition of insect assemblages using 1,760 samples collected in 160 stream sites. Catchment‐ and site‐scale variables both explained significant variation in EPT taxon and trait composition. Substrate, habitat hydromorphology and land use most influenced variation in taxonomic composition, whereas trait composition was mainly affected by land use. Catchment geographic position explained less assemblage variation. To our knowledge, this study is the first assessment of the impact of catchment‐ and site‐scale variables on the trait and taxon composition of stream insect assemblages in Neotropical savanna streams. It highlights the need for better regional biological knowledge of invertebrates to generate more general trait‐based approaches in freshwater ecosystem conservation.

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Section: Introductionmentioning

confidence: 99%

Landscape variables influence taxonomic and trait composition of insect assemblages in Neotropical savanna streams

2017

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“…Nonlinear responses to threats, whereby ecosystems change dramatically from one state to another at a given alteration level, ultimately lead to different temporal scales of impact and recovery (Dodds et al, 2010). Multiple alterations can also act simultaneously or sequentially (Taniwaki et al, 2016), including one alteration triggering another, further challenging the ability to identify and isolate the role of individual threats in the landscape. A better understanding of when and where threats overlap can help determine the relevance of interactions to guide scientific studies and inform management.…”

Section: Understanding the Spatial And Temporal Extent Of Interactionsmentioning

confidence: 99%

“…Yet metrics of ecosystem function (e.g., metabolism, nutrient uptake and transformation, decomposition, secondary production) may be more useful for characterizing cumulative system response to a wide range of environmental alterations, and are especially effective when used in combination with organismal response (Rosi-Marshall and Royer, 2012;Taniwaki et al, 2016), as structural and functional responses may differ (or show stronger responses in combination) and link to different management objectives.…”

Section: Determining How To Measure the Effects Of Multiple Threatsmentioning

confidence: 99%

Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers

Craig

Olden

Arthington

et al. 2017

Elementa: Science of the Anthropocene

103

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Human activities create threats that have consequences for freshwater ecosystems and, in most watersheds, observed ecological responses are the result of complex interactions among multiple threats and their associated ecological alterations. Here we discuss the value of considering multiple threats in research and management, offer suggestions for filling knowledge gaps, and provide guidance for addressing the urgent management challenges posed by multiple threats in freshwater ecosystems. There is a growing literature assessing responses to multiple alterations, and we build off this background to identify three areas that require greater attention: linking observed alterations to threats, understanding when and where threats overlap, and choosing metrics that best quantify the effects of multiple threats. Advancing science in these areas will help us understand existing ecosystem conditions and predict future risk from multiple threats. Because addressing the complex issues and novel ecosystems that arise from the interaction of multiple threats in freshwater ecosystems represents a significant management challenge, and the risks of management failure include loss of biodiversity, ecological goods, and ecosystem services, we also identify actions that could improve decision-making and management outcomes. These actions include drawing insights from management of individual threats, using threat attributes (e.g., causes and spatio-temporal dynamics) to identify suitable management approaches, testing management strategies that are likely to be successful despite uncertainties about the nature of interactions among threats, avoiding unintended consequences, and maximizing conservation benefits. We also acknowledge the broadly applicable challenges of decision-making within a socio-political and economic framework, and suggest that multidisciplinary teams will be needed to innovate solutions to meet the current and future challenge of interacting threats in freshwater ecosystems.

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“…Climate change is expected to impact the structure and functioning of tropical streams by altering hydrological, thermal, and chemical (e.g., dissolved oxygen) conditions (Strauch, MacKenzie, Bruland, & Giardina, ; Taniwaki, Piggott, Ferraz, & Matthaei, ). Stream systems are particularly important in Hawai'i because they provide more than 50% of irrigation water to the islands (Oki, ), host endemic stream fauna, and influence the condition of nearshore coastal habitats.…”

Section: Introductionmentioning

confidence: 99%

Long‐term streamflow trends in Hawai'i and implications for native stream fauna

Clilverd

Tsang

Infante

et al. 2019

Hydrological Processes

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Climate change has fundamentally altered the water cycle in tropical islands, which is a critical driver of freshwater ecosystems. To examine how changes in streamflow regime have impacted habitat quality for native migratory aquatic species, we present a 50‐year (1967–2016) analysis of hydrologic records in 23 unregulated streams across the five largest Hawaiian Islands. For each stream, flow was separated into direct run‐off and baseflow and high‐ and low‐flow statistics (i.e., Q10 and Q90) with ecologically important hydrologic indices (e.g., frequency of flooding and low flow duration) derived. Using Mann–Kendall tests with a running trend analysis, we determined the persistence of streamflow trends through time. We analysed native stream fauna from ~400 sites, sampled from 1992 to 2007, to assess species richness among islands and streams. Declines in streamflow metrics indicated a general drying across the islands. In particular, significant declines in low flow conditions (baseflows), were experienced in 57% of streams, compared with a significant decline in storm flow conditions for 22% of streams. The running trend analysis indicated that many of the significant downward trends were not persistent through time but were only significant if recent decades (1987–2016) were included, with an average decline in baseflow and run‐off of 10.90% and 8.28% per decade, respectively. Streams that supported higher native species diversity were associated with moderate discharge and baseflow index, short duration of low flows, and negligible downward trends in flow. A significant decline in dry season flows (May–October) has led to an increase in the number of no‐flow days in drier areas, indicating that more streams may become intermittent, which has important implications for mauka to makai (mountain to ocean) hydrological connectivity and management of Hawai'i's native migratory freshwater fauna.

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Climate change and multiple stressors in small tropical streams

Cited by 65 publications

References 122 publications

Landscape variables influence taxonomic and trait composition of insect assemblages in Neotropical savanna streams

Landscape variables influence taxonomic and trait composition of insect assemblages in Neotropical savanna streams

Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers

Long‐term streamflow trends in Hawai'i and implications for native stream fauna

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