Effective Conservation Actions Research Articles

Identifying and assessing the efficiency of different networks of a fine-scale hierarchy of biodiversity hotspots

Background: For prioritising practical conservation measures in areas of high endemic plant diversity, a fine-scale hierarchy of sites needs to be established. In this context, conservation sites designed at local and regional levels are considered a network of interconnected areas.Aims: The main aim was to identify two hierarchical levels of a network of conservation sites, called ‘micro hotspots’ and ‘nano hotspots’, and test their efficiency for achieving conservation objectives across the island of Sardinia, Mediterranean Basin.Methods: We analysed the spatial distribution of endemic vascular plant species (EVPS) richness. Additionally, the area, perimeter, connectivity and surplus costs for the protection of all endemic plant populations were used as ranking criteria for a hierarchical classification.Results: We identified eight micro hotspots and 82 nano hotspots. Amongst the three possible solutions compared, the integrated network of micro and nano hotspots resulted in more effective conservation than any of the single-level network solutions with only micro or nano hotspots, and it included 89% of all EVPS in a relatively small areal extent.Conclusions: The identification of hotspot networks at the regional level allowed determining priority areas to implement conservation efforts for EVPS. The integration of micro hotspots with nano hotspots resulted in the most effective network from both conservation and economic perspectives. We suggest that our model may provide an effective tool for integrated and effective conservation actions in the Mediterranean Basin.

DNA barcoding as a tool for robust identification of cervids of India and its utility in wildlife forensics

DNA barcoding has become a popular method of choice for identification of specimen based on molecular techniques. Here, we present preliminary findings on generating robust DNA barcode library of Cervids of India. The dataset comprising the DNA barcode library of seven deer species included in the genus Cervus, Axis and Muntiacus classified under family Cervidae. Mitochondrial Cytochrome C Oxidase subunit I gene of ca. 710 bp accepted widely as DNA barcode region, was used for generating species specific signature from 31 known samples of seven Indian deer species. Expectedly, the NJ tree clustered three genera i.e. Cervus, Axis and Muntiacus of Cervids of India into three clades. Further, the intra- and interspecies distances based on Kimura 2 parameter model also supported the results. The average intra- and interspecies sequence divergence were 0.011 (±0.09) and 0.65 (±0.14), respectively. The present study has exhibited that DNA barcoding has discriminating power to delineate boundaries among the closely related species. The data generated are of high importance to the law enforcement agencies in effective identification of species in wildlife offence cases. The similar approach can be utilized for generating DNA barcodes for other Indian mammals for making effective management and conservation action decisions.

Integration of genetic and seed fitness data to the conservation of isolated subpopulations of the Mediterranean plant Malcolmia littorea.

Plant autoecology and population genetics provide a perspective on the likelihood of natural regeneration, which is critical when designing conservation strategies for endangered species. The threatened coastal plant Malcolmia littorea (Brassicaceae) was sampled across its European distribution and studied for genetic diversity and seed fitness, with the aim of providing information for the conservation of isolated and declining populations. Nine microsatellite markers (five chloroplast and four nuclear) were analysed to assess population genetic diversity and structure and to conduct a spatial analysis using the software DIVA-GIS. Germination percentages and rates were assessed by incubating the seeds under eight constant temperatures (0-27°C). The genetic diversity was found to be similar among subpopulations (chloroplast H=0.04-0.17; nuclear Ho =0.20-0.37), with no correlation between subpopulation diversity and the area of occupancy (AOO). The subpopulations were found to be clustered in three genetic groups, and three of them were identified as conservation priorities due to their unique genetic composition. The germination study revealed a significant influence of the maternal environment and AOO on seed germination, with the smaller subpopulations showing lower germination percentages (P<0.05). These results highlight the importance of obtaining information on isolated subpopulations through different experimental approaches (e.g. seed germination plus population genetics) to enable planning of effective conservation actions. For M.littorea, seed collection for both insitu and ex situ conservation should take into account the local adaptation of the subpopulation and the genetic structure of the species.

Reptile surveys reveal high species richness in areas recovering from mining activity in the Brazilian Cerrado

AbstractOur study determines the reptile species richness, composition, and habitat use in three areas recovering from mining activity in addition to the adjacent pristine and anthropized areas of a priority region for biodiversity conservation of the Brazilian Cerrado. We also compared our data with published surveys on the Cerrado domain in order to identify areas with unique species composition and/or areas where the reptile composition is more homogeneous. The survey was conducted in the municipality of Niquelândia, northern Goiás state, central Brazil, and involved reptile samplings from different physiognomies and water bodies. We found 47 species, including one crocodilian, one chelonian, two amphisbaenians, 17 lizards, and 26 snakes. The list includes 37 species with large geographic distribution, occurring in other morphoclimatic domains, as well as 10 species which are endemic to the Cerrado. Some species recorded for the region are listed in the Appendices I and II of the CITES. Many reptile species were frequently associated with anthropogenic habitats, while others seem to depend on remnants of pristine habitats. Low similarity was found among the 32 sites considered across the Cerrado domain. Ten sites located in Cerrado regions in contact with the adjacent domains have unique reptile composition, whereas most sites largely located in the central area of the domain have reptile communities which are more homogeneous among them. It is important to conduct long-term studies to have patterns of reptile species composition recognized as well as population decline and/or local extinctions and effective reptile conservation actions, with focus on these sites considering their unique species.

The culture of bird conservation: Australian stakeholder values regarding iconic, flagship and rare birds

Iconic, flagship and rare threatened bird taxa attract disproportionate amounts of public attention, and are often used to enable broader conservation strategies. Yet, little is known about why certain taxa achieve iconic or flagship status. Also unclear is whether the perception of rarity among those acting to conserve threatened birds is sufficient to influence attitudes and behaviour that lead to effective conservation action and, if so, which characteristics of rare birds are important to their conservation. We interviewed 74 threatened bird conservation stakeholders to explore perceptions about iconic, flagship and rare threatened birds and classified their attitudes using a new typology of avifaunal attitudes. There was a relationship between societal interest and conservation effort for threatened species characterised as iconic, flagship and rare. Iconic species tended to arouse interest or emotion in people due to being appealing and readily encountered, thereby attracting conservation interest that can benefit other biodiversity. Flagships tended to have distinguishing physical or cultural characteristics and were used to convey conservation messages about associated biodiversity. Attitudes about rarity mostly related to a taxon’s threatened status and small population size. Rarity was important for threatened bird conservation but not always associated with attitudes and behaviour that lead to effective conservation action. We conclude that conservation action for individual threatened bird taxa is biased and directly influenced by the ways taxa are socially constructed by stakeholders, which is specific to prevailing culture and stakeholder knowledge.

Are culvert assessment scores an indicator of Brook Trout Salvelinus fontinalis population fragmentation?

Fragmentation is a major threat to the integrity of stream ecosystems and maintaining connectivity is a primary goal for conservation to promote natural system functioning. In human dominated systems with extensive anthropogenic fragmentation, resource managers are faced with prioritizing restoration actions to provide the most cost-effective conservation strategies. Road crossings, particularly poorly designed culverts, limit fish passage and thus population connectivity and access to seasonally important resources. Culvert assessment protocols, such as the one developed by the North Atlantic Aquatic Connectivity Collaborative (NAACC), are useful tools for managers to evaluate culvert passability and prioritize restoration actions across broad spatial extents, however the justification of such protocols requires empirical field based investigations. In this study we collected Brook Trout genetic samples from 28 headwater streams, of which 17 were separated by a culverted road crossing and 11 were included as a comparison to natural genetic structuring. The objectives of this research were to 1) determine what effect culverts had on the genetics of Brook Trout populations, 2) evaluate the ability of the NAACC culvert assessment protocol to predict genetic patterns and 3) identify the culvert characteristics that best explained genetic variability. We found significant increases in genetic differentiation at sites with culverts compared to those without, but no differences in genetic diversity metrics. Although the NAACC classifications did not predict the extent of genetic differentiation, the openness ratio of culverts (cross sectional area/length) was significantly correlated, suggesting it may need to receive a higher weighting in assessment protocols. Our results highlight the necessity to match appropriate prioritization strategies with desired management objectives in order to design the most effective conservation actions.

Sharing fishers\xb4 ethnoecological knowledge of the European pilchard (Sardina pilchardus) in the westernmost fishing community in Europe

BackgroundWith the present difficulties in the conservation of sardines in the North Atlantic, it is important to investigate the local ecological knowledge (LEK) of fishermen about the biology and ecology of these fish. The ethnoecological data of European pilchard provided by local fishermen can be of importance for the management and conservation of this fishery resource. Thus, the present study recorded the ethnoecological knowledge of S. pilchardus in the traditional fishing community of Peniche, Portugal.MethodsThis study was based on 87 semi-structured interviews conducted randomly from June to September 2016 in Peniche. The interview script contained two main points: Profile of fishermen and LEK on European pilchard. The ethnoecological data of sardines were compared with the scientific literature following an emic-etic approach. Data collected also were also analysed following the union model of the different individual competences and carefully explored to guarantee the objectivity of the study.ResultsThe profile of the fishermen was investigated and measured. Respondents provided detailed informal data on the taxonomy, habitat, behaviour, migration, development, spawning and fat accumulation season of sardines that showed agreements with the biological data already published on the species. The main uses of sardines by fishermen, as well as beliefs and food taboos have also been mentioned by the local community.ConclusionsThe generated ethnoecological data can be used to improve the management of this fishery resource through an adaptive framework among the actors involved, in addition to providing data that can be tested in further ecological studies. Therefore, this local knowledge may have the capacity to contribute to more effective conservation actions for sardines in Portugal.

Climatic vulnerability of the world’s freshwater and marine fishes

To understand how species will cope with warming, knowledge of the thermal limits is needed. This study estimates 2,960 ray-fin fish species’ thermal sensitivity. Comparison with projected warming highlights vulnerable freshwater and marine regions. Climate change is a mounting threat to biological diversity1, compromising ecosystem structure and function, and undermining the delivery of essential services worldwide2. As the magnitude and speed of climate change accelerates3, greater understanding of the taxonomy and geography of climatic vulnerability is critical to guide effective conservation action. However, many uncertainties remain regarding the degree and variability of climatic risk within entire clades and across vast ecosystem boundaries4. Here we integrate physiological estimates of thermal sensitivity for 2,960 ray-finned fishes with future climatic exposure, and demonstrate that global patterns of vulnerability differ substantially between freshwater and marine realms. Our results suggest that climatic vulnerability for freshwater faunas will be predominantly determined by elevated levels of climatic exposure predicted for the Northern Hemisphere, whereas marine faunas in the tropics will be the most at risk, reflecting their higher intrinsic sensitivity. Spatial overlap between areas of high physiological risk and high human impacts, together with evidence of low past rates of evolution in upper thermal tolerance, highlights the urgency of global conservation actions and policy initiatives if harmful climate effects on the world’s fishes are to be mitigated in the future.

Substantial decline of Northern European peatland bird populations: Consequences of drainage

Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peatland species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habitat preferences of peatland bird species, hence helping to target conservation to the most relevant habitat types. There was a general decline of 40% in Northern European peatland bird population sizes in 1981–2014 (speed of decline 1.5%/year) largely driven by Finland, where populations declined almost 50% (2.0% annual decline). In Sweden and Norway, peatland bird populations declined by 20% during 1997–2014 (1.0% annual decline). In contrast, southern populations in Estonia and Latvia, where the majority of open peatlands are protected, showed a 40% increase during 1981–2014 (1.0% annual increase). The most important habitat characteristics preferred by common peatland species in Finland were openness and low tree height, while wetness proved to be an important feature for waders. Drainage of peatlands had clear negative effects on the densities of many species, with the only exception of rustic bunting, which specializes on edge habitats. Our findings call for more effective conservation actions in Northern European peatland habitats, especially in Finland where peatland drainage represents a major threat to biodiversity.

Penguin Promises: encouraging aquarium visitors to take conservation action

This study investigates the impact of an innovative conservation action campaign called Penguin Promises implemented at uShaka Sea World in Durban, South Africa. Communication tools included interpretive signage, exhibits with and without animals, presentations, and personal interactions, along with a specially designed postcard, on which visitors could write a promise (pledge) to make a change in their daily lives to become more environmentally responsible. Visitors who completed a card were contacted a year or more after their visit and asked about the outcomes of their promise. The results (N = 316) showed that 49.4% of respondents could give an example of something positive they had done for the environment, that they attributed to the campaign. Based on the study, recommendations are provided for the design of effective visitor conservation action campaigns.

Evaluating management strategies in the conservation of the critically endangered Blue-throated Macaw (Ara glaucogularis)

We model the dynamics of the remaining wild population of the Blue-throated Macaw (Ara glaucogularis), a critically endangered and Bolivian endemic species exposed to different management strategies. The model becomes a tool to quantify how effective management actions may be. We construct a birth-pulse, post breeding census, deterministic, stage structured projection matrix model to describe the population dynamics. The model shows that population growth is sensitive to changes in the probability of survival in the adult stage, followed by changes in fertility. We describe the long-term behavior of the population as result of the combination of the maternity function and the nestlings’ survival probability. Under the scenarios of increasing population, the number of years that are necessary to double the current wild population varied between 33 and 215 years without reintroduction, and between 7 and 46 years if 50 adult macaws are reintroduced ten years later since the simulation starts. Stakeholders of the Blue-throated Macaw Conservation Project may profit from a simple graphical tool based on this model for management decision making. By knowing the adult population size and the number of hatched eggs at the beginning of each breeding season, the field team could assess the necessary effort on nestlings’ management to increase the chances of a positive population growth. Evaluating beforehand the impact of management actions on Blue-throated Macaws could contribute to the improvement and effectiveness of conservation actions on the critically endangered Blue-throated Macaw population.

Understanding the effects of different social data on selecting priority conservation areas.

Conservation success is contingent on assessing social and environmental factors so that cost-effective implementation of strategies and actions can be placed in a broad social-ecological context. Until now, the focus has been on how to include spatially explicit social data in conservation planning, whereas the value of different kinds of social data has received limited attention. In a regional systematic conservation planning case study in Australia, we examined the spatial concurrence of a range of spatially explicit social values and land-use preferences collected using a public participation geographic information system and biological data. We used Zonation to integrate the social data with the biological data in a series of spatial-prioritization scenarios to determine the effect of the different types of social data on spatial prioritization compared with biological data alone. The type of social data (i.e., conservation opportunities or constraints) significantly affected spatial prioritization outcomes. The integration of social values and land-use preferences under different scenarios was highly variable and generated spatial prioritizations 1.2-51% different from those based on biological data alone. The inclusion of conservation-compatible values and preferences added relatively few new areas to conservation priorities, whereas including noncompatible economic values and development preferences as costs significantly changed conservation priority areas (48.2% and 47.4%, respectively). Based on our results, a multifaceted conservation prioritization approach that combines spatially explicit social data with biological data can help conservation planners identify the type of social data to collect for more effective and feasible conservation actions.

Assessing Bat Roosts Using the LiDAR System at Wind Cave Nature Reserve in Sarawak, Malaysian Borneo

Conventionally, bat roost counts and roost size estimation are potentially a disruptive, repetitive method and are time consuming. Introduction of the Light Detection and Ranging (LiDAR) scanning system, an optical remote sensing technology, for scientific purposes have open many research possibilities especially on cave wildlife surveys. Scanned images at high resolution provide new effective biological tools for assessing bat roosts inside caves on walls or ceiling in total darkness. LiDAR system was applied to census bats that roost in Wind Cave Nature Reserve, Sarawak, Malaysia, based on laser return intensity values from the images. Bats that roost in large clusters, specifically Penthetor lucasi were determined through automated counting using connected components labelling, a graph theory algorithm mostly used in image analysis applications. Roost surface area of bats species was calculated based on point clouds extracted and using simple trigonometry. Wind Cave was successfully modelled into three dimensional (3D) cave images with bats roosting inside the cave. The roost sites of bats in the cave were represented in coloured point clouds that represent the species. Through LiDAR images, bats in Wind Cave consisted of about 979 individuals of P. lucasi and 1,907 individuals of insectivorous bats from nine species representing four families. There is a positive correlation between group size and roost area. For every additional bat, roost area is expected to increase by an average of 1.75 m2. Our result suggested that terrestrial LiDAR technology is capable of assessing bat roosts in their natural habitat to determine their roost size and number of individuals that roost in the cave. Terrestrial LiDAR application is most complementary when integrated with field surveys to produce more reliable outcomes which open up possibilities of effective conservation action plans.

Why management decisions involving marine mammals should include animal welfare

This paper argues the need for consideration of both animal welfare and conservation when making management decisions regarding human activities that affect marine mammals. Population level effects may take a long time to be determined, whereas animal welfare metrics can be observed in the short term, enabling problems to be addressed more rapidly. In addition, implementing current legislation in many countries related to the management of impacts on marine mammals requires animal welfare to be taken into account. Such legislation reflects societal values and public concern for individual animals. Two case studies are discussed. These are: management measures related to incidental killing in commercial fisheries, and injury or disturbance from intense sources of underwater noise from seismic surveys. Both of these threats have welfare and conservation implications for marine mammals. An increased focus on welfare would better reflect societal values including requirements under various legal regimes and could also enable more targeted and effective conservation actions.

Delimiting priority areas for the conservation of endemic and threatened Neotropical birds using a niche-based gap analysis.

Knowledge of spatiotemporal distribution of biodiversity is still very incomplete in the tropics. This is one of the major problems preventing the assessment and effectiveness of conservation actions. Mega-diverse tropical regions are being exposed to fast and profound environmental changes, and the amount of resources available to describe the distribution of species is generally limited. Thus, the tropics is losing species at unprecedented rates, without a proper assessment of its biodiversity. Species distribution models (SDMs) can be used to fill such biogeographic gaps within a species’ range and, when allied with systematic conservation planning (e.g. analyses of representativeness, gap analysis), help transcend such data shortage and support practical conservation actions. Within the Neotropics, eastern Amazon and northern Cerrado present a high variety of environments and are some of the most interesting ecotonal areas within South America, but are also among the most threatened biogeographic provinces in the world. Here, we test the effectiveness of the current system of Protected Areas (PAs), in protecting 24 threatened and endemic bird species using SDMs. We found that taxa with wider distributions are potentially as protected as taxa with smaller ranges, and larger PAs were more efficient than smaller PAs, while protecting these bird species. Nonetheless, Cerrado PAs are mostly misallocated. We suggest six priority areas for conservation of Neotropical birds. Finally, we highlight the importance of indigenous lands in the conservation of Neotropical biodiversity, and recommend the development of community management plans to conserve the biological resources of the region.

Postcards from the Field

Increasingly, botanic gardens and arboreta are highlighted as effective partners to conserve plant species diversity and restore natural communities at a time when the need for these activities has become more urgent. Capacity for restoration and conservation at botanic gardens comes directly from staff expertise for horticulture and research. Botanic gardens make good partners for connecting botanical science with conservation practice. They are in a position to communicate information about rare plant species to owners and managers of public and private lands, and they can be instrumental in creating networks for effective conservation action. Several examples from south-eastern United States of America illustrate how this has been put into practice. These examples provide evidence that efforts to expand collaboration between federal agencies, states and non-governmental organisations can lead to effective alliances to conserve plant biodiversity, especially when plants receive a disproportionately low share of resources for conservation.

Scientific Evidence and Potential Barriers in the Management of Brazilian Protected Areas.

Protected areas are a crucial tool for halting the loss of biodiversity. Yet, the management of protected areas is under resourced, impacting the ability to achieve effective conservation actions. Effective management depends on the application of the best available knowledge, which can include both scientific evidence and the local knowledge of onsite managers. Despite the clear value of evidence-based conservation, there is still little known about how much scientific evidence is used to guide the management of protected areas. This knowledge gap is especially evident in developing countries, where resource limitations and language barriers may create additional challenges for the use of scientific evidence in management. To assess the extent to which scientific evidence is used to inform management decisions in a developing country, we surveyed Brazilian protected area managers about the information they use to support their management decisions. We targeted on-ground managers who are responsible for management decisions made at the local protected area level. We asked managers about the sources of evidence they use, how frequently they assess the different sources of evidence and the scientific content of the different sources of evidence. We also considered a range of factors that might explain the use of scientific evidence to guide the management of protected areas, such as the language spoken by managers, the accessibility of evidence sources and the characteristics of the managers and the protected areas they manage. The managers who responded to our questionnaire reported that they most frequently made decisions based on their personal experience, with scientific evidence being used relatively infrequently. While managers in our study tended to value scientific evidence less highly than other sources, most managers still considered science important for management decisions. Managers reported that the accessibility of scientific evidence is low relative to other types of evidence, with key barriers being the low levels of open access research and insufficient technical training to enable managers to interpret research findings. Based on our results, we suggest that managers in developing countries face all the same challenges as those in developed countries, along with additional language barriers that can prevent greater use of scientific evidence to support effective management of protected areas in Brazil.

An inexpensive satellite-download GPS receiver for wildlife: field trial on black swans

Context Knowledge of the movements and space-use patterns of wildlife is crucial for implementation of effective conservation and management actions. Such information can be difficult to obtain, especially from hard-to-capture or far-ranging taxa. Global-positioning-system (GPS) receivers that have remote data-acquisition capability via satellite-communication networks offer an effective means of tracking highly mobile animals; however, often the equipment and operational costs of these devices are prohibitive. Aim To evaluate the operational performance and potential of an inexpensive, commercially available satellite-download GPS receiver that can be easily modified for use on wildlife, and to demonstrate its utility for revealing novel information on individual animal movements in an important wildlife management context. Methods We added external batteries and supplementary waterproofing to ‘off-the-shelf’ SPOT Trace® GPS receivers (~$120 USD; Spot LLC, Covington, LA) that transmit recorded location data to users through the Globalstar satellite network. We then deployed these devices on eight wild black swans (Cygnus atratus) inhabiting a large inland marine harbor adjacent to Auckland International Airport and assessed the GPS units’ operational performance and overall cost effectiveness. Key results During field trials with the tracking devices lasting up to 25 days we were able to collect thousands of precision location observations from the swans without the need for recapture. Cost-per-fix was only ~$0.04 USD – up to an order of magnitude lower than some satellite-download GPS receivers manufactured specifically for wildlife. We provide novel information about the swans’ patterns of activity, movement, space-use, habitat preferences and responses to actions taken by airport staff to scare problem individuals from threat zones. Conclusions User-modified satellite-download GPS devices can be a highly cost-effective means of tracking the movements of animals. Implications Knowledge of where and when swans present the greatest likely threat to air traffic and how they respond to displacement from restricted areas near the airport will be useful in devising threat-management plans. The ready availability of affordable remote-download GPS receivers will provide many new opportunities to study the movement and/or space-use patterns of wildlife and incorporate such information into a broad range of research and management programs.

SNPs selected by information content outperform randomly selected microsatellite loci for delineating genetic identification and introgression in the endangered dark European honeybee (Apis mellifera mellifera)

The honeybee (Apis mellifera) has been threatened by multiple factors including pests and pathogens, pesticides and loss of locally adapted gene complexes due to replacement and introgression. In western Europe, the genetic integrity of the native A. m. mellifera (M-lineage) is endangered due to trading and intensive queen breeding with commercial subspecies of eastern European ancestry (C-lineage). Effective conservation actions require reliable molecular tools to identify pure-bred A. m. mellifera colonies. Microsatellites have been preferred for identification of A. m. mellifera stocks across conservation centres. However, owing to high throughput, easy transferability between laboratories and low genotyping error, SNPs promise to become popular. Here, we compared the resolving power of a widely utilized microsatellite set to detect structure and introgression with that of different sets that combine a variable number of SNPs selected for their information content and genomic proximity to the microsatellite loci. Contrary to every SNP data set, microsatellites did not discriminate between the two lineages in the PCA space. Mean introgression proportions were identical across the two marker types, although at the individual level, microsatellites' performance was relatively poor at the upper range of Q-values, a result reflected by their lower precision. Our results suggest that SNPs are more accurate and powerful than microsatellites for identification of A. m. mellifera colonies, especially when they are selected by information content.

Pelagic Nekton Abundance and Distribution in the Northern Sacramento–San Joaquin Delta, California

AbstractKnowledge of the habitats occupied by species is fundamental for the development of effective conservation and management actions. The collapse of pelagic fish species in the Sacramento–San Joaquin Delta, California, has triggered a need to better understand factors that drive their distribution and abundance. A study was conducted in summer–fall 2014 in an attempt to identify physical and biological habitat conditions that drive the abundance and distribution of pelagic species in the northern region of the system. The study was conducted in the three largest channels in the northern Sacramento–San Joaquin Delta by dimension, volume, and flow capacity. The pelagic community was dominated by three nonnative species, Siberian prawn Exopalaemon modestus, which comprised 56% of the total number of organisms, and two fish species, Threadfin Shad Dorosoma petenense and Mississippi Silversides Menidia audens, which together comprised 43% of the total number of organisms. Total fish and total shrimp abundance were sensitive to the most extreme values of turbidity and temperature encountered and positively associated with total zooplankton biomass. The results suggested that habitat conditions in terminal channels, historically a common feature on the landscape, support higher abundances of pelagic species and zooplankton than open‐ended channels. These results provide resource managers with useful information on the habitat associations of pelagic species and on how the future distribution and abundance of pelagic species will likely change in response to climate or other ecological factors.Received March 8, 2016; accepted September 22, 2016 Published online December 9, 2016