Life Sciences Commons^™

Fixed Versus Random Sampling Designs In Small South Dakota Glacial Lakes, Bradley J. Smith, Nathan S. Kruger, Nicholas S. Voss, Brian G. Blackwell

The Prairie Naturalist

Choice of sampling design is fundamental when planning surveys to monitor fisheries resources. However, little is known about the impact that different sampling designs may have on commonly collected fish population metrics used to index relative abundance, size structure, and diversity in small (<200 ha) glacial lakes. To address this issue, we sampled three small glacial lakes in eastern South Dakota with modified fyke nets and gill nets at fixed sites used by South Dakota Game, Fish and Parks and a complement of nets at randomized sites. Catch per unit effort (CPUE), proportional size distribution (PSD), and PSD-preferred (PSD-P) were compared between fixed and random designs for each species and gear by lake while Bray-Curtis distances were calculated between sample designs for each gear type in each lake. Precision of CPUE estimates for routinely indexed species were calculated for both gears used by each sampling design. No consistent bias in calculated population metrics was detected between sampling designs for any species collected with either gear type in the three lakes. Sampling precision of CPUE estimates were low for both gears and study designs; though randomized sites tended to yield lower precision. Power analyses indicated that current levels of sampling effort are insufficient to detect differences in CPUE or PSD/PSD-P between fixed and random sampling designs. In addition to being small, study lakes had relatively homogenous habitat allowing for effective sampling resulting in similar values of CPUE and PSD/PSD-P for both fixed and random study designs, and high assemblage overlap. We conclude that fixed sampling sites provide adequate representation of fish communities in small glacial lakes and are sufficient for monitoring temporal changes in these small, but numerous, systems.

Nonnative Forest Insects And Pathogens In The United States: Impacts And Policy Options, Gary M. Lovett, Marissa Weiss, Andrew M. Liebhold, Thomas P. Holmes, Brian Leung, Kathy F. Lambert, David A. Orwig, Faith T. Campbell, Jonathan Rosenthal, Deborah G. Mccullough, Radka Wildova, Matthew P. Ayres

Dartmouth Scholarship

We review and synthesize information on invasions of nonnative forest insects and diseases in the United States, including their ecological and economic impacts, pathways of arrival, distribution within the United States, and policy options for reducing future invasions. Nonnative insects have accumulated in United States forests at a rate of ~2.5 per yr over the last 150 yr. Currently the two major pathways of introduction are importation of live plants and wood packing material such as pallets and crates. Introduced insects and diseases occur in forests and cities throughout the United States, and the problem is particularly severe in the …

Using Standardized Fishery Data To Inform Rehabilitation Efforts, Jonathan J. Spurgeon, Nathaniel T. Stewart, Mark A. Pegg, Kevin L. Pope, Mark T. Porath

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Lakes and reservoirs progress through an aging process often accelerated by human activities, resulting in degradation or loss of ecosystem services. Resource managers thus attempt to slow or reverse the negative effects of aging using a myriad of rehabilitation strategies. Sustained monitoring programs to assess the efficacy of rehabilitation strategies are often limited; however, long-term standardized fishery surveys may be a valuable data source from which to begin evaluation.We present 3 case studies using standardized fishery survey data to assess rehabilitation efforts stemming from the Nebraska Aquatic Habitat Plan, a large-scale program with the mission to rehabilitate waterbodies within the …

Management Applications Of Discontinuity Theory, David G. Angeler, Craig R. Allen, Chris Barichievy, Tarsha Eason, Ahjond S. Garmestani, Nicholas A.J. Graham, Dean Granholm, Lance H. Gunderson, Melinda Knutson, Kristy L. Nash, R. John Nelson, Magnus Nystrom, Trisha L. Spanbauer, Craig A. Stow, Shana M. Sundstrom

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

1. Human impacts on the environment are multifaceted and can occur across distinct spatiotemporal scales. Ecological responses to environmental change are therefore difficult to predict, and entail large degrees of uncertainty. Such uncertainty requires robust tools for management to sustain ecosystem goods and services and maintain resilient ecosystems.

2. We propose an approach based on discontinuity theory that accounts for patterns and processes at distinct spatial and temporal scales, an inherent property of ecological systems. Discontinuity theory has not been applied in natural resource management and could therefore improve ecosystem management because it explicitly accounts for ecological complexity.

3. Synthesis …