Questioning the Cost

The keynote address to the 71st annual meeting of the Air Pollution Control Association was presented by The Honorable Lloyd Bentsen. Excerpts from his address follow:     

Poor acclimation capacities in Antarctic marine ectotherms

Animals can respond to temperature change by the following means: using physiological flexibility (including acclimation); or adapting; or migrating, with acclimation proposed as the major mechanism dictating prospects for survival in marine groups. In this study, 6 species of Antarctic invertebrate covering 4 phyla, Echinodermata, Mollusca, Brachiopoda and Crustacea were subjected to acclimation trials at 3°C for 60 days. Using acute upper lethal temperatures as a metric of ability to acclimate, only one species (Marseniopsis mollis) increased its acute upper limit. Furthermore, analysis of oxygen consumption on the urchin Sterechinus neumayeri and the amphipod Paraceradocus gibber showed their metabolic rates were also not compensated over the 60-day exposure period. Thus, 5 out of 6 species failed to acclimate to temperatures only 3.5°C above the annual average and 1–2°C above current summer maximum values. We discuss the proposal that the abilities of Antarctic marine species to adjust to elevated environmental temperatures are as limited, if not more so, than tropical species.     

Limited contributions of released animals from zoos to North American conservation translocations

With the loss of biodiversity accelerating, conservation translocations such as reintroductions are becoming an increasingly common conservation tool. Conservation translocations must source individuals for release from either wild or captive-bred populations. We asked what proportion of North American conservation translocations rely on captive breeding and to what extent zoos and aquaria (hereafter zoos) fulfill captive breeding needs. We searched for mention of captive breeding and zoo involvement in all 1863 articles included in the North American Conservation Translocations database, which comprises journal articles and grey literature published before 2014 on conservation translocations in Canada, the United States, Mexico, the Caribbean, and Central America before 2014 as identified by a comprehensive literature review. Conservation translocations involved captive breeding for 162 (58%) of the 279 animal species translocated. Fifty-four zoos contributed animals for release. The 40 species of animals bred for release by zoos represented only 14% of all animal species for which conservation translocations were published and only 25% of all animal species that were bred for releases occurring in North America. Zoo contributions varied by taxon, ranging from zoo-bred animals released in 42% of amphibian conservation translocations to zero contributions for marine invertebrates. Proportional involvement of zoos in captive-breeding programs for release has increased from 1974 to 2014 (r = 0.325, p = 0.0313) as has the proportion of translocation-focused scientific papers coauthored by zoo professionals (from 0% in 1974 to 42% in 2013). Although zoos also contribute to conservation translocations through education, funding, and professional expertise, increasing the contribution of animals for release in responsible conservation translocation programs presents a future conservation need and opportunity. We especially encourage increased dialogue and planning between the zoo community, academic institutions, and governments to optimize the direct contribution zoos can make to wildlife conservation through conservation translocations.     

Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii

Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA.     

Very slow development in two Antarctic bivalve molluscs,the infaunal clam <Emphasis Type="Italic">Laternula elliptica</Emphasis> and the scallop <Emphasis Type="Italic">Adamussium colbecki</Emphasis>

Embryos of the large infaunal clam Laternula elliptica and the scallop Adamussium colbecki, from Antarctica, were cultured over an 18-month period. Their development rates were extremely slow, taking 240 and 177 h, respectively, to reach the trochophore stage. This is ×4 to ×18 slower than related clams and scallops from temperate latitudes. The relationship between temperature and development rate for bivalve molluscs shows the expected slowing with reduced temperature (Q ₁₀ in the range 2–4) for temperate and tropical species. However, the slowing at polar latitudes is much stronger than at warmer waters, and all of the limited data for Antarctic species are well above the Arrhenius plot for the overall bivalve data, and the Q ₁₀ value for Antarctic to cool temperate species is 11.8, well outside the expected range for biological systems. Either the relationships describing the effects of temperature on the kinetics of biological systems do not apply to Antarctic bivalve molluscs, or some other factor that cannot be compensated for becomes important at low temperature. In the laboratory, L. elliptica embryos stayed viable in very sticky egg capsules for up to 18 months without hatching. However, even the disturbance of removing eggs using a pipette ruptured some egg capsules allowing embryo release. Gametogenesis in Antarctic marine invertebrates is almost universally slowed compared to temperate species, with nearly all cases documented requiring more than 1 year to complete oogenesis. The only exception so far appears to be A. colbecki, which has a 1-year gametogenic cycle. The data here indicate that it has been unable to adapt embryonic development in a similar way, and we are not aware of any exceptions to the markedly slowed development at low temperature rule.     

Male-biased sex ratios in New Zealand fur seal pups relative to environmental variation

A number of models have been proposed to provide adaptive explanations of sex-ratio variation in mammals. Two models have been applied commonly to primates and ungulates with varying success—the Trivers-Willard (TW) hypothesis, and the local resource competition (LRC) hypothesis. For polygynous, sexually dimorphic mammals, where males are larger and disperse more readily, these models predict opposite outcomes of sex-ratio adjustment within the same environmental context (high-resource years: TW—more sons; LRC—more daughters). However, many of the predictions of these two models can vary depending on factors influencing resource availability, such as environmental stochasticity, resource predictability, and population density. The New Zealand fur seal (Arctocephalus forsteri) is a polygynous mammal showing marked sexual dimorphism (larger males), with higher variation in male reproductive success expected. We provide clear evidence of male-biased sex ratios from a large sample of A. forsteri pups captured around South Island, New Zealand during 1996/1998, even after accounting for a sex bias in capture probability. The extent of the bias depended upon year and, in 1998, strong climatic perturbations (El Niño/Southern Oscillation, ENSO) probably reduced food availability. Significant male-biased sex ratios were found in all years; however, there was a significant decline in the male bias in 1998. There was no relationship between sex ratio and population density. We suggest that the sex-ratio bias resulted from the production of relatively more male pups. Under the density-independent scenario, the strong male bias in A. forsteri sex ratios is support for the TW model within an environment of high resource predictability. We suggest that some plasticity in the determination of pup sex among years is a mechanism by which A. forsteri females in New Zealand, and perhaps other otariid seals, can maximise fitness benefits when living in regions of high, yet apparently predictable, environmental variability. We also suggest that much of the inconsistency in the reported sex ratios for otariid seals results from the complex interaction of population density and environmental stochasticity influencing relative food availability over time.     

Sibling recognition in Richardson's ground squirrels (Spermophilus richardsonii)

Summary Young from 10 litters of Richardson's ground squirrels were crossfostered within 24 h of birth. Litters, composed then of uterine-sibs and fostered non-sibs, were caged together until 37 days of age (1 week after weaning), at which time the juveniles were separated and caged individually. At a mean age of 110 d squirrels were tested for recognition during 10-min trials in an arena using the following pair-types: sibs reared together (SRT), sibs reared apart (SRA), non-sibs reared together (NSRT), and non-sibs reared apart (NSRA). Juvenile S. richardsonii displayed an ability, determined prenatally or soon after birth, to recognize their biological siblings. Familiarity, based upon association before and at the time of weaning, also affected discrimination between conspecifics, although this effect was less apparent.     

An apparatus for measuring microbial growth or survival in the marine environment

The apparatus consists of a glass tube closed at the top and with a bacteria-proof sinter-glass filter at the lower end. This is moored below the surface of the sea after inoculation with the organism under examination. Water enters and leaves the tube due to the hydrostatic pressure differential created by tides and waves; this gives a desirable rate of exchange of sea water withouth allowing the entry of any foreign organisms. After the period of immersion, the amount of growth or survival of the organism is estimated.