@article{sivakoff_morris_aschehoug_hudgens_haddad_2016, title={Habitat restoration alters adult butterfly morphology and potential fecundity through effects on host plant quality}, volume={7}, ISSN={["2150-8925"]}, DOI={10.1002/ecs2.1522}, abstractNote={Conservation strategies for threatened species frequently include habitat restoration, but the success of such recovery efforts has been mixed. When the target is an insect herbivore, restoration efforts have traditionally attempted to increase the abundance of its host plant, but these actions' impact on host plant quality has largely been ignored. Here, we test the impact of two forms of habitat restoration, tree removal and stream damming, on the physical and chemical properties of a wetland sedge and on the adult traits of its larval consumer, a wetland butterfly. Tree removal altered plant physical and chemical traits in a manner largely consistent with reduced host plant quality. Females emerging from these plots had fewer mature oocytes in their ovaries upon emergence, suggesting that tree removal has a negative effect on butterfly potential fecundity. Stream damming did not affect plant traits but forewing length increased more steeply with body mass for females from these plots, indicating that small females from dammed plots have a relatively higher wing loading ratio that likely increases the energetic cost of flight. This idea was supported by results from our subsequent capture–mark–recapture study, where both female and male butterflies were less likely to emigrate from dammed plots. Male dispersal was also affected by restoration, but individual body mass rather than wing allometry mediated this effect. Our results highlight the need to consider restoration's impact on host plant quality, in addition to other aspects of habitat quality, when undertaking habitat restoration for threatened herbivores.}, number={11}, journal={ECOSPHERE}, author={Sivakoff, Frances S. and Morris, William F. and Aschehoug, Erik T. and Hudgens, Brian R. and Haddad, Nick M.}, year={2016}, month={Nov} }
 @article{aschehoug_sivakoff_cayton_morris_haddad_2015, title={Habitat restoration affects immature stages of a wetland butterfly through indirect effects on predation}, volume={96}, ISSN={["1939-9170"]}, DOI={10.1890/14-2403.1}, abstractNote={Habitat loss worldwide has led to the widespread use of restoration practices for the recovery of imperiled species. However, recovery success may be hampered by focusing on plant communities, rather than the complex suite of direct and indirect interactions among trophic levels that occur in natural systems. Through a factorial field experiment, we tested the effects of wetland restoration on egg and juvenile survival of a locally rare butterfly, Satyrodes appalachia, via tree removal and damming. Tree removal more than tripled S. appalachia host plant abundance, but neither restoration action directly affected S. appalachia egg and juvenile survival. Instead, we found strong indirect effects of habitat manipulation on S. appalachia egg and juvenile survival that were mediated through predation. The interaction of tree removal and damming significantly decreased predation of S. appalachia eggs relative to each treatment alone. Damming alone had a significant positive indirect effect on the survival of S. appalachia juveniles, likely because increases in standing water reduced predator access. Our results emphasize the need for experiments that evaluate the demographic responses of imperiled species to habitat restoration prior to management action and quantify potential indirect effects mediated through higher trophic levels.}, number={7}, journal={ECOLOGY}, author={Aschehoug, Erik T. and Sivakoff, F. S. and Cayton, H. L. and Morris, W. F. and Haddad, N. M.}, year={2015}, month={Jul}, pages={1761–1767} }
 @article{sivakoff_rosenheim_dutilleul_carriere_2013, title={Influence of the surrounding landscape on crop colonization by a polyphagous insect pest}, volume={149}, ISSN={["1570-7458"]}, DOI={10.1111/eea.12101}, abstractNote={Landscape composition plays an important, but poorly understood, role in the population dynamics of agricultural pest species with broad host ranges including both crops and weeds. One such pest, the generalist plant bug Lygus hesperus Knight (Hemiptera: Miridae), is a key cotton pest that feeds on various hosts differing in quality in California's San Joaquin Valley (USA). We investigated the effects of 15 common crops and uncultivated agricultural land on L. hesperus populations, by correlating the densities of L. hesperus in focal cotton fields with the areas of the 16 crops in surrounding rings. Insect counts were provided by private pest‐control advisors, and spatial data were obtained from Kern County records. We first calculated Spearman's partial correlation coefficients on an annual basis for each crop separately, and then performed a meta‐analysis of these correlations across years to describe the overall effect of a particular crop on L. hesperus after the effects of the 15 other crops are removed. Consistent with studies conducted in other areas, L. hesperus density was positively correlated with safflower, and negatively with cotton. Lygus hesperus density was also correlated with several other crops that are often not considered in pest management, including grape, oat, and onion (positive correlations), and almond, pistachio, and potato (negative correlations). Lygus hesperus density was also found to be negatively correlated with alfalfa and positively correlated with uncultivated habitats, a relationship that receives mixed support in the literature. Several other crops tested were not significantly correlated with L. hesperus densities in focal cotton fields, suggesting a neutral role for them in L. hesperus dynamics. The improved understanding of the effects of a greater variety of crops on L. hesperus population dynamics will be useful in the design of agricultural landscapes for enhanced management of this important polyphagous pest.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Sivakoff, Frances S. and Rosenheim, Jay A. and Dutilleul, Pierre and Carriere, Yves}, year={2013}, month={Oct}, pages={11–21} }