We used a field experiment, population modeling, and an analysis of 30 years of data from walleye (Sander vitreus; a freshwater fish) in Lake Erie to show that maternal influences on offspring survival can affect population dynamics. We first demonstrate experimentally that the survival of juvenile walleye increases with egg size (and, to a lesser degree, female energy reserves). Because egg size in this species tends to increase with maternal age, we then model these maternal influences on offspring survival as a function of maternal age to show that adult age structure can affect the maximum rate at which a population can produce new adults. Consistent with this hypothesis, we present empirical evidence that the maximum reproductive rate of an exploited population of walleye was approximately twice as high when older females were abundant as compared to when they were relatively scarce. Taken together, these results indicate that age- or size-based maternal influences on offspring survival can be an important mechanism driving population dynamics and that exploited populations could benefit from management strategies that protect, rather than target, reproductively valuable individuals.

Highlights d Successive founder effects caused progressive loss of genetic diversity in the muskox d Evidence of strong population structure in the muskox d Extremely low genetic diversity in the Greenlandic muskox populations d Arctic mammals show striking similarities in their genetic history

Peregrine falcon populations underwent devastating declines in the mid-20th century due to the bioaccumulation of organochlorine contaminants, becoming essentially extirpated east of the Great Plains and significantly reduced elsewhere in North America. Extensive re-introduction programs and restrictions on pesticide use in Canada and the United States have returned many populations to predecline sizes. A proper population genetic appraisal of the consequences of this decline requires an appropriate context defined by (i) meaningful demographic entities; and (ii) suitable reference populations. Here we explore the validity of currently recognized subspecies designations using data from the mitochondrial control region and 11 polymorphic microsatellite loci taken from 184 contemporary individuals from across the breeding range, and compare patterns of population genetic structure with historical patterns inferred from 95 museum specimens. Of the three North American subspecies, the west coast marine subspecies Falco peregrinus pealei is well differentiated genetically in both time periods using nuclear loci. In contrast, the partitioning of continental Falco peregrinus anatum and arctic Falco peregrinus tundrius subspecies is not substantiated, as individuals from these subspecies are historically indistinguishable genetically. Bayesian clustering analyses demonstrate that contemporary genetic differentiation between these two subspecies is mainly due to changes within F. p. anatum (specifically the southern F. p. anatum populations). Despite expectations and a variety of tests, no genetic bottleneck signature is found in the identified populations; in fact, many contemporary indices of diversity are higher than historical values. These results are rationalized by the promptness of the recovery and the possible introduction of new genetic material.

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A more complete description of African elephant phylogeography would require a method that distinguishes forest and savanna elephants using DNA from low-quality samples. Although mitochondrial DNA is often the marker of choice for species identification, the unusual cytonuclear patterns in African elephants make nuclear markers more reliable. We therefore designed and utilized genetic markers for short nuclear DNA regions that contain fixed nucleotide differences between forest and savanna elephants. We used M13 forward and reverse sequences to increase the total length of PCR amplicons and to improve the quality of sequences for the target DNA. We successfully sequenced fragments of nuclear genes from dung samples of known savanna and forest elephants in the Democratic Republic of Congo, Ethiopia, and Namibia. Elephants at previously unexamined locations were found to have nucleotide character states consistent with their status as savanna or forest elephants. Using these and results from previous studies, we estimated that the short-amplicon nuclear markers could distinguish forest from savanna African elephants with more than 99% accuracy. Nuclear genotyping of museum, dung, or ivory samples will provide better-informed conservation management of Africa's elephants.