A perspective on dryland river ecosystems

Walker, Keith F.; Sheldon, Fran; Puckridge, J. T.

doi:10.1002/rrr.3450110108

Cited by 349 publications

(266 citation statements)

References 63 publications

(52 reference statements)

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“…The Death Valley model predicts that remnant populations across the MBD landscape have a high level of between-population structure, but no significant basin or catchment structure, no IBD, no gene flow and small local population size, perhaps driven by naturally chaotic and variable patterns of stream connectivity exacerbated by human-driven change (Walker et al, 1995). The nonequilibrium model is defined by a high level of local extinction with infrequent recolonization events (Nei and Chakravarti, 1977), indicative of a species decline in fragmented habitats.…”

Section: Discussionmentioning

confidence: 99%

Landscape genetics informs mesohabitat preference and conservation priorities for a surrogate indicator species in a highly fragmented river system

et al. 2016

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Poor dispersal species represent conservative benchmarks for biodiversity management because they provide insights into ecological processes influenced by habitat fragmentation that are less evident in more dispersive organisms. Here we used the poorly dispersive and threatened river blackfish (Gadopsis marmoratus) as a surrogate indicator system for assessing the effects of fragmentation in highly modified river basins and for prioritizing basin-wide management strategies. We combined individual, population and landscape-based approaches to analyze genetic variation in samples spanning the distribution of the species in Australia's Murray-Darling Basin, one of the world's most degraded freshwater systems. Our results indicate that G. marmoratus displays the hallmark of severe habitat fragmentation with notably scattered, small and demographically isolated populations with very low genetic diversity-a pattern found not only between regions and catchments but also between streams within catchments. By using hierarchically nested population sampling and assessing relationships between genetic uniqueness and genetic diversity across populations, we developed a spatial management framework that includes the selection of populations in need of genetic rescue. Landscape genetics provided an environmental criterion to identify associations between landscape features and ecological processes. Our results further our understanding of the impact that habitat quality and quantity has on habitat specialists with similarly low dispersal. They should also have practical applications for prioritizing both large-and small-scale conservation management actions for organisms inhabiting highly fragmented ecosystems.

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Section: Discussionmentioning

confidence: 99%

Landscape genetics informs mesohabitat preference and conservation priorities for a surrogate indicator species in a highly fragmented river system

et al. 2016

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“…Consequently, its middle section is largely allogenic, analogous to a dryland river as described by Walker et al (1995). Tributary influx to the Missouri River is greatest in the lowermost section, and variability in frequency and duration of high-flow pulses and discharge is also high here.…”

Section: Natural Factors Contribute To Spatio-temporal Variability Inmentioning

confidence: 91%

Restoring ecological integrity of great rivers: historical hydrographs aid in defining reference conditions for the Missouri River

Galat

Lipkin

2000

Assessing the Ecological Integrity of Running Waters

118

169

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Restoring the ecological integrity of regulated large rivers necessitates characterizing the natural flow regime. We applied 'Indicators of Hydrologic Alteration' to assess the natural range of variation of the Missouri River's flow regime at 11 locations before (1929-1948) and after (1967-1996) mainstem impoundment. The 3768 km long Missouri River was divided into three sections: upper basin least-altered from flow regulation, including the lower Yellowstone River; middle basin inter-reservoir, and lower basin channelized. Flow regulation was associated with a reduction in magnitude and duration of the annual flood pulse, an increase in magnitude and duration of annual discharge minima, a reduction in frequency of annual low-flow pulses, earlier timing of March-October low-flow pulses, and a general increase in frequency of flow reversals with a reduction in the rate of change in river flows. Hydrologic alterations were smallest at two least-altered upper-basin sites and most frequent and severe in interreservoir and upper-channelized river sections. The influence of reservoir operations on depressing the annual flood pulse was partially offset by tributary inflow in the lower 600 km of river. Reservoir operations could be modified to more closely approximate the 1929-1948 flow regime to establish a simulated natural riverine ecosystem. For inter-reservoir and upper channelized-river sections, we recommend periodic controlled flooding through managed reservoir releases during June and July; increased magnitude, frequency and duration of annual high-flow pulses; and increased annual rates of hydrograph rises and falls. All of the regulated Missouri River would benefit from reduced reservoir discharges during August-February, modified timing of reservoir releases and a reduced number of annual hydrograph reversals. Assessment of ecological responses to a reregulation of Missouri River flows that more closely approximates the natural flow regime should then be used in an adaptive fashion to further adjust reservoir operations.

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“…The spatio-temporal dynamics of vegetation are, therefore, largely determined by available water [68][69][70][71][72][73]. Not surprisingly, biotic diversity is concentrated in riparian areas [74,75].…”

Section: Figurementioning

confidence: 99%

Genetic consequences of postglacial colonization by the endemic Yarkand hare (Lepus yarkandensis) of the arid Tarim Basin

Shan

Liu

et al. 2011

Chin. Sci. Bull.

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Orogenesis of the Qinghai-Tibetan Plateau, which occurred in a stepwise manner, contributed to the extreme aridity of the Tarim Basin, resulting in vulnerable and unstable ecosystems. Quaternary climatic oscillations may have affected the ecosystems and, consequently, the distributions and genetic structuring of the Tarim Basin's biota. We used nucleotide sequence data from 2 mitochondrial (mt) DNA genes (Cyt b and the D-loop) to test hypotheses associated with the matrilineal and demographical histories of the Tarim Basin's endemic Yarkand hare (Lepus yarkandensis). Range-wide sampling involving 20 populations and 224 individuals detected 126 haplotypes that clustered into 5 major lineages in both the phylogenetic tree and median-joining network. Populations from the northern and eastern Tarim Basin shared a similar history, as did those from the western and southern regions. Demographical analysis and genetic diversity estimations suggested that the western and southern regions might have served as glacial refugia for the Yarkand hare during Quaternary climatic oscillations. The distribution of the Yarkand hare, especially in the northern and eastern parts, probably represented 3 postglacial colonization events, dated to 0.21, 0.090 and 0.054 MYA, which corresponded to known interglacial periods. Given the relatively complete geographic isolation between the eastern and southern populations, the Yarkand hare likely dispersed during postglacial periods from the southwest to the north, and then onward to the east. The absence of water likely forced the species into refugia, and this differed from other Pleistocene biogeographical drivers. The demographical and historical patterns have important implications for conservation. Chinese Sci Bull, 2011, 56: 1370−1382, doi: 10.1007 Pleistocene climatic changes imposed significant range shifts on many Palearctic biota, and contributed to their demographic history and genetic diversity [1]. Many temperate species existed only in refugia at times of glacial maxima, and recolonized or expanded into newly available habitats during interglacial periods [2,3]. Quaternary evolutionary histories of European and North American biota *These authors contributed equally to this work †Corresponding authors

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A perspective on dryland river ecosystems

Cited by 349 publications

References 63 publications

Landscape genetics informs mesohabitat preference and conservation priorities for a surrogate indicator species in a highly fragmented river system

Landscape genetics informs mesohabitat preference and conservation priorities for a surrogate indicator species in a highly fragmented river system

Restoring ecological integrity of great rivers: historical hydrographs aid in defining reference conditions for the Missouri River

Genetic consequences of postglacial colonization by the endemic Yarkand hare (Lepus yarkandensis) of the arid Tarim Basin

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