Addressing the Gender Gap in Distinguished Speakers at Professional Ecology Conferences

Keynote and plenary speakers at professional conferences serve as highly visible role models for early-career scientists and provide recognition of scientific excellence. This recognition may be particularly important for women, who are underrepresented in senior positions in the biological sciences. To evaluate whether conferences fulfill this potential, we examined distinguished speakers at North American ecology conferences between 2000 and 2015 and compared these data with the percentage of women ecologists at diverse career stages. We found that 15%–35% (x = 28%, n = 809) of the distinguished speakers were women, which is significantly lower than the percentage of female ecology graduate students (x = 55%, n = 26,802) but consistent with the percentage of women in assistant- and associate-faculty positions. We recommend that conference organizers institute policies to enhance speaker gender balance, to provide support for speakers with family responsibilities, and to actively monitor gender-related trends in their societies to achieve the equitable representation of women in distinguished speaking roles

Addressing the Gender Gap in Distinguished Speakers at Professional Ecology Conferences

Keynote and plenary speakers at professional conferences serve as highly visible role models for early-career scientists and provide recognition of scientific excellence. This recognition may be particularly important for women, who are underrepresented in senior positions in the biological sciences. To evaluate whether conferences fulfill this potential, we examined distinguished speakers at North American ecology conferences between 2000 and 2015 and compared these data with the percentage of women ecologists at diverse career stages. We found that 15%–35% (x = 28%, n = 809) of the distinguished speakers were women, which is significantly lower than the percentage of female ecology graduate students (x = 55%, n = 26,802) but consistent with the percentage of women in assistant- and associate-faculty positions. We recommend that conference organizers institute policies to enhance speaker gender balance, to provide support for speakers with family responsibilities, and to actively monitor gender-related trends in their societies to achieve the equitable representation of women in distinguished speaking roles

Can Orchards Help Connect Mediterranean Ecosystems? Animal Movement Data Alter Conservation Priorities

As natural habitats become fragmented by human activities, animals must increasingly move through human-dominated systems, particularly agricultural landscapes. Mapping areas important for animal movement has therefore become a key part of conservation planning. Models of landscape connectivity are often parameterized using expert opinion and seldom distinguish between the risks and barriers presented by different crop types. Recent research, however, suggests different crop types, such as row crops and orchards, differ in the degree to which they facilitate or impede species movements. Like many mammalian carnivores, bobcats (Lynx rufus) are sensitive to fragmentation and loss of connectivity between habitat patches. We investigated how distinguishing between different agricultural land covers might change conclusions about the relative conservation importance of different land uses in a Mediterranean ecosystem. Bobcats moved relatively quickly in row crops but relatively slowly in orchards, at rates similar to those in natural habitats of woodlands and scrub. We found that parameterizing a connectivity model using empirical data on bobcat movements in agricultural lands and other land covers, instead of parameterizing the model using habitat suitability indices based on expert opinion, altered locations of predicted animal movement routes. These results emphasize that differentiating between types of agriculture can alter conservation planning outcomes

Wildlife Habitat Use in Agriculture-Dominated Landscapes

Conservation practitioners are increasingly looking to agricultural landscapes as potential habitat or movement areas for wildlife. Use of human-dominated landscapes for conservation is likely to increase as pressures from land use and climate change grow. A better understanding of wildlife use of agricultural lands is necessary if they are to be incorporated in conservation plans. My research addresses wildlife use of agriculture-dominated landscapes in California. In Chapter 1, I examine how a quantitative assessment of wildlife-habitat relationships can be used to predict impacts of land use change, using changes associated with biofuel production in California as a case study. I determined that the California Wildlife Habitat Relationship (CWHR) database systematically underestimates the value of agricultural habitats for wildlife, and I therefore updated the CWHR with extensive information compiled from literature and from interviews with California wildlife researchers and managers. The modified CWHR database correlated with field observations of birds across the state, indicating that the database has sufficient accuracy to be useful in predicting impacts of land use change. In Chapter 2, I narrowed my focus to one agriculture-wildlife system: avocado orchards used by mammalian carnivores. I used remote-triggered cameras to document use of avocado orchards by mammalian carnivores, and found that most local carnivore species use orchards, and that avocado orchards are positively associated with number of detections of bobcats, gray foxes, and coyotes. In Chapter 3, I examined individual movement data from four GPS-collared bobcats. I used compositional analysis methods to compare habitat selection and found that bobcats chose orchards more than would be expected based on their availability in the landscape. Next, I quantified movement rates in orchards versus other land use types and found that these animals move slowly through avocado orchards and at similar rates as in woodland and scrub vegetation, suggesting that avocados function as habitat on par with natural habitats. I used data on habitat selection and relative rates of movement to parameterize a connectivity model across the study region, and found that differentiating cropland from orchards changed the areas where animals were expected to move

Biofuels And Biodiversity In California: Trade-off Analysis

Biofuels from agricultural and other biomass are an important part of California’s strategy to reduce greenhouse gas emissions and dependence on foreign oil. Ongoing land conversion for agricultural and urban uses has already imperiled many animal species in the state. This study investigated the potential impacts on wildlife of shifts in agricultural activity to increase biomass production. We applied knowledge of the suitability of California’s agricultural landscapes for wildlife species to evaluate wildlife effects associated with plausible scenarios of expanded production of five potential biofuel crops (sweet sorghum, sugar beets, bermudagrass, canola, and safflower). We generated alternative, spatially-explicit scenarios that minimized loss of habitat for a given level of biofuel production. Trade-off analysis compared the marginal changes per unit of energy for transportation costs, wildlife, and water-use. The choice of crop matters. Sweet sorghum and sugar beets require three times less land area per gallon of gasoline equivalent than bermudagrass and five to six times less than canola and safflower. Canola and safflower scenarios had the largest impacts on wildlife but the greatest reduction in water use. The bermudagrass scenarios would result in a slight overall improvement for wildlife over the current situation. Relatively minor redistribution of lands converted to biofuel could produce the same energy yield with much less impact on wildlife and very small increases in transportation costs for any crop. This framework provides a means to systematically evaluate potential wildlife impacts of alternative production scenarios. The accuracy of the predicted impacts could be improved with additional field study of wildlife use of agricultural landscapes, especially habitats associated with biofuel crops

Demographic Heterogeneity, Cohort Selection, and Population Growth

Demographic heterogeneity—variation among individuals in survival and reproduction—is ubiquitous in natural populations. Structured population models address heterogeneity due to age, size, or major developmental stages. However, other important sources of demographic heterogeneity, such as genetic variation, spatial heterogeneity in the environment, maternal effects, and differential exposure to stressors, are often not easily measured and hence are modeled as stochasticity. Recent research has elucidated the role of demographic heterogeneity in changing the magnitude of demographic stochasticity in small populations. Here we demonstrate a previously unrecognized effect: heterogeneous survival in long-lived species can increase the long-term growth rate in populations of any size. We illustrate this result using simple models in which each individual\u27s annual survival rate is independent of age but survival may differ among individuals within a cohort. Similar models, but with nonoverlapping generations, have been extensively studied by demographers, who showed that, because the more “frail” individuals are more likely to die at a young age, the average survival rate of the cohort increases with age. Within ecology and evolution, this phenomenon of “cohort selection” is increasingly appreciated as a confounding factor in studies of senescence. We show that, when placed in a population model with overlapping generations, this heterogeneity also causes the asymptotic population growth rate λ to increase, relative to a homogeneous population with the same mean survival rate at birth. The increase occurs because, even integrating over all the cohorts in the population, the population becomes increasingly dominated by the more robust individuals. The growth rate increases monotonically with the variance in survival rates, and the effect can be substantial, easily doubling the growth rate of slow-growing populations. Correlations between parent and offspring phenotype change the magnitude of the increase in λ, but the increase occurs even for negative parent–offspring correlations. The effect of heterogeneity in reproductive rate on λ is quite different: growth rate increases with reproductive heterogeneity for positive parent–offspring correlation but decreases for negative parent–offspring correlation. These effects of demographic heterogeneity on λ have important implications for population dynamics, population viability analysis, and evolution

Carnivore use of avocado orchards across an agricultural-wildland gradient.

Wide-ranging species cannot persist in reserves alone. Consequently, there is growing interest in the conservation value of agricultural lands that separate or buffer natural areas. The value of agricultural lands for wildlife habitat and connectivity varies as a function of the crop type and landscape context, and quantifying these differences will improve our ability to manage these lands more effectively for animals. In southern California, many species are present in avocado orchards, including mammalian carnivores. We examined occupancy of avocado orchards by mammalian carnivores across agricultural-wildland gradients in southern California with motion-activated cameras. More carnivore species were detected with cameras in orchards than in wildland sites, and for bobcats and gray foxes, orchards were associated with higher occupancy rates. Our results demonstrate that agricultural lands have potential to contribute to conservation by providing habitat or facilitating landscape connectivity

Land use change and rodenticide exposure trump climate change as the biggest stressors to San Joaquin kit fox.

Animal and plant species often face multiple threats simultaneously. We explored the relative impact of three major threats on populations of the endangered San Joaquin kit fox. This species was once widely distributed across the southern San Joaquin Valley, California, USA, but agriculture and urban development have replaced much of its natural habitat. We modeled impacts of climate change, land-use change, and rodenticide exposure on kit fox populations using a spatially explicit, individual-based population model from 2000 to 2050 for the Central Valley, California. Our study indicates that land-use change will likely have the largest impact on kit fox populations. Land development has the potential to decrease populations by approximately 15% under a compact growth scenario in which projected population increases are accommodated within existing urban areas, and 17% under a business-as-usual scenario in which future population growth increases the developed area around urban centers. Plausible scenarios for exposure to pesticides suggest a reduction in kit fox populations by approximately 13%. By contrast, climate change has the potential to ameliorate some of these impacts. Climate-change induced vegetation shifts have the potential to increase total available kit fox habitat and could drive population increases of up to 7%. These vegetation shifts could also reduce movement barriers and create opportunities for hybridization between the endangered San Joaquin kit fox and the more widely distributed desert kit fox, found in the Mojave Desert. In contrast to these beneficial impacts, increasing climate extremes raise the probability of the kit fox population dropping below critical levels. Taken together, these results paint a complex picture of how an at-risk species is likely to respond to multiple threats