Human impacts on the Waikato River system, New Zealand

Human intervention, pre-human climate change (or a combination of both), as well as genetic effects, contribute to species extinctions. While many species from oceanic islands have gone extinct due to direct human impacts, the effects of pre-human climate change and human settlement on the genomic diversity of insular species and the role that loss of genomic diversity played in their extinctions remains largely unexplored. To address this question, we sequenced whole genomes of two extinct New Zealand passerines, the huia ( Heteralocha acutirostris ) and South Island kōkako ( Callaeas cinereus ). Both species showed similar demographic trajectories throughout the Pleistocene. However, the South Island kōkako continued to decline after the last glaciation, while the huia experienced some recovery. Moreover, there was no indication of inbreeding resulting from recent mating among closely related individuals in either species. This latter result indicates that population fragmentation associated with forest clearing by Maōri may not have been strong enough to lead to an increase in inbreeding and exposure to genomic erosion. While genomic erosion may not have directly contributed to their extinctions, further habitat fragmentation and the introduction of mammalian predators by Europeans may have been an important driver of extinction in huia and South Island kōkako.

Download Full-text

James C. Knox (1977) Human impacts on Wisconsin stream channels. Annals of the Association of American Geographers 67: 224–244.

Progress in Physical Geography Earth and Environment ◽

10.1177/0309133313490008 ◽

2013 ◽

Vol 37 (3) ◽

pp. 422-431 ◽

Cited By ~ 5

Author(s):

William L. Graf

Keyword(s):

Mississippi River ◽

Human Impacts ◽

Professional Community ◽

River System ◽

Stream Channels ◽

Early 19Th Century ◽

Driftless Area ◽

University Of Wisconsin ◽

History Of ◽

Floodplain Deposits

James C. Knox’s 1977 paper “Human Impacts on Wisconsin Stream Channels,” published in the Annals of the Association of American Geographers, was a key component of a suite of three papers by him defining the response of rivers to the introduction and management of agriculture and to climate change. In this paper he used the Driftless Area of southwest Wisconsin as a laboratory where he could define fluvial responses by their sedimentary signatures in floodplain deposits. Land-use records dating back to the early 19th century along with shorter climate records provided his understanding of the drivers of change. He found that floods increased as an outcome of land-cover change. Upstream tributaries became wider and shallower as coarse deposits limited their adjustments, while main stem channels became narrower and deeper. His paper reflected the influence of his graduate advisor and especially of prominent faculty colleagues at the University of Wisconsin from fields ranging from soils and climatology to geomorphology and history. The paper was the subject of considerable debate in the professional community, but it remains a much-cited example of Knox’s work in unraveling the Quaternary and Holocene history of rivers of the Driftless Area and by extension the upper Mississippi River system.

Download Full-text

Metal concentrations of resident and transplanted freshwater mussels Hyridella menziesi (Unionacea: Hyriidae) and sediments in the Waikato River, New Zealand

The Science of The Total Environment ◽

10.1016/0048-9697(95)04722-0 ◽

1995 ◽

Vol 175 (3) ◽

pp. 163-177 ◽

Cited By ~ 24

Author(s):

C HICKEY ◽

D ROPER ◽

S BUCKLAND

Keyword(s):

New Zealand ◽

Freshwater Mussels ◽

Metal Concentrations ◽

Waikato River

Download Full-text

Range reduction of the Oblong Rocksnail, Leptoxis compacta, shapes riverscape genetic patterns

10.1101/2020.05.12.090662 ◽

2020 ◽

Author(s):

Aaliyah D. Wright ◽

Nicole L. Garrison ◽

Ashantye’ S. Williams ◽

Paul D. Johnson ◽

Nathan V. Whelan

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Human Impacts ◽

Isolation By Distance ◽

Extinction Risk ◽

River System ◽

High Genetic Diversity ◽

Range Contraction ◽

Genetic Patterns ◽

Cahaba River

AbstractMany freshwater gastropod species face extinction, including 79% of species in the family Pleuroceridae. The Oblong Rocksnail, Leptoxis compacta, is a narrow range endemic pleurocerid from the Cahaba River basin in central Alabama that has seen rapid range contraction in the last 100 years. Such a decline is expected to negatively affect genetic diversity in the species. However, precise patterns of genetic variation and gene flow across the restricted range of L. compacta are unknown. This lack of information limits our understanding of human impacts on the Cahaba River system and Pleuroceridae. Here, we show that L. compacta has likely seen a species-wide decline in genetic diversity, but remaining populations have relatively high genetic diversity. We also report a contemporary range extension compared to the last published survey. Leptoxis compacta does not display an isolation by distance pattern, contrasting patterns seen in many riverine taxa. Our findings also indicate that historical range contraction has resulted in the absence of common genetic patterns seen in many riverine taxa like isolation by distance as the small distribution of L. compacta allows for relatively unrestricted gene flow across its remaining range despite limited dispersal abilities. Two collection sites had higher genetic diversity than others, and broodstock sites for future captive propagation and reintroduction efforts should utilize sites identified here as having the highest genetic diversity. Broadly, our results support the hypothesis that range contraction will result in the reduction of species-wide genetic diversity, and common riverscape genetic patterns cannot be assumed to be present in species facing extinction risk.

Download Full-text

Range reduction of Oblong Rocksnail, Leptoxis compacta, shapes riverscape genetic patterns

PeerJ ◽

10.7717/peerj.9789 ◽

2020 ◽

Vol 8 ◽

pp. e9789

Author(s):

Aaliyah D. Wright ◽

Nicole L. Garrison ◽

Ashantye’ S. Williams ◽

Paul D. Johnson ◽

Nathan V. Whelan

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Human Impacts ◽

Isolation By Distance ◽

Extinction Risk ◽

River System ◽

High Genetic Diversity ◽

Range Contraction ◽

Genetic Patterns ◽

Cahaba River

Many freshwater gastropod species face extinction, including 79% of species in the family Pleuroceridae. The Oblong Rocksnail, Leptoxis compacta, is a narrow range endemic pleurocerid from the Cahaba River basin in central Alabama that has seen rapid range contraction in the last 100 years. Such a decline is expected to negatively affect genetic diversity in the species. However, precise patterns of genetic variation and gene flow across the restricted range of L. compacta are unknown. This lack of information limits our understanding of human impacts on the Cahaba River system and Pleuroceridae. Here, we show that L. compacta has likely seen a species-wide decline in genetic diversity, but remaining populations have relatively high genetic diversity. We also report a contemporary range extension compared to the last published survey. Our findings indicate that historical range contraction has resulted in the absence of common genetic patterns seen in many riverine taxa like isolation by distance as the small distribution of L. compacta allows for relatively unrestricted gene flow across its remaining range despite limited dispersal abilities. Two collection sites had higher genetic diversity than others, and broodstock sites for future captive propagation and reintroduction efforts should utilize sites identified here as having the highest genetic diversity. Broadly, our results support the hypothesis that range contraction will result in the reduction of species-wide genetic diversity, and common riverscape genetic patterns cannot be assumed to be present in species facing extinction risk.

Download Full-text