P. Dee Boersma

Limiting abuse: marine protected areas, a limited solution

Abstract Designation of marine protected areas (MPAs) is increasing as humans seek to combat overexploitation of marine resources and preserve the integrity of the ocean’s unique biodiversity. At present there are over 1300 MPAs. The primary legal responsibility for the designation of MPAs falls to individual countries, but protection of the marine environment at large scales is also critical because ocean circulation does not honor legal boundaries and often exceeds the influence of any one nation or group of nations. There are many reasons for establishing MPAs; the papers we surveyed principally referred to scientific, economic, cultural, and ethical factors. Two approaches predominated: fisheries management and habitat protection. Although the major threat to terrestrial systems is habitat loss, the major threats to the world’s oceans are fisheries overexploitation, coastal development, and chemical and biological pollution. MPAs may provide conservation of formerly exploited species as well as benefits to the fishery through leakage of ‘surplus’ adults (spillover) and larvae (larval replenishment) across reserve boundaries. Higher order effects, such as changes in species richness or changes in community structure and function, have only been superficially explored. Because many MPAs are along coastlines, within shipping lanes, and near human centers of activity, the chance of chemical and biological pollution is high. Use of MPAs to combat development and pollution is not appropriate, because MPAs do not have functional boundaries. The ocean is a living matrix carrying organisms as well as particles and therefore even relatively environmentally sensitive uses of coastal ecosystems can degrade ecosystem structure and function via increasing service demands (e.g. nutrient and toxics transformation) and visitation. Whether an MPA is effective is a function of the initial objectives, the level of enforcement, and its design. Single reserves need to be large and networked to accommodate bio-physical patterns of larval dispersal and recruitment. Some authors have suggested that reserve size needs to be extremely large — 50–90% of total habitat — to hedge against the uncertainties of overexploitation. On a local scale, marine protected areas can be effective conservation tools. On a global scale, MPAs can only be effective if they are substantively representative of all biogeographic zones, single reserves are networked within biogeographic zones, and the total amount of area reserved per zone is 20% or greater. The current size and placement of protected areas falls far short of comprehensive or even adequate conservation objectives.

Penguins as Marine Sentinels

ABSTRACT From the tropics to Antarctica, penguins depend on predictable regions of high ocean productivity where their prey aggregate. Increases in precipitation and reductions in sea ice associated with climate warming are affecting penguins. The largest breeding colony of Patagonian (Magellanic) penguins, at Punta Tombo, Argentina, had approximately 200,000 breeding pairs in October 2006—a decline of 22% since 1987. In the 1980s and 1990s, petroleum pollution was a major source of Patagonian penguin mortality. In 1994, tanker lanes were moved 40 kilometers (km) farther off the coast of Chubut, and the dumping of ballast water and the oiling of penguins are now rare. However, penguins are swimming 60 km farther north from their nests during incubation than they did a decade ago, very likely reflecting shifts in prey in response to climate change and reductions in prey abundance caused by commercial fishing. These temperate penguin species, marine sentinels for southern oceans, demonstrate that new challenges are confronting their populations.

Parental quality and selection on egg size in the Magellanic penguin

We examined the relative contributions of egg size and parental quality to hatching success, fledging success, and chick growth in the Magellanic penguin (Spheniscus magellanicus) be exchanging clutches between nests to reduce the covariation between egg and parental factors. Among control nests, fledging success increased slightly with egg size. However, the effect of egg size independently of parental quality was limited to an influence on chick mass and size for the first 10 days post‐hatching. In contrast, attributes of the parents influenced nesting success and chick size at fledging, independently of the egg size actually raised. We suggest that the common occurrence of a positive phenotypic correlation between egg size and fledging success is due to two factors: (1) adults laying large eggs tend to be of higher quality; and (2) to the extent that egg size does influence early survival independently of parental quality, the effect on survival is due to a maternal effect on egg composition rather than an inherent effect of egg size.

Field Endocrinology and Conservation Biology

Abstract Field endocrinology techniques allow the collection of samples (i.e., blood, urine, feces, tissues) from free-living animals for analysis of hormones, receptors, enzymes, etc. These data reveal mechanisms by which individuals respond to environmental challenges, breed, migrate and regulate all aspects of their life cycles. Field endocrinology techniques can also be used to address many issues in conservation biology. We briefly review past and current ways in which endocrine methods are used to monitor threatened species, identify potential stressors and record responses to environmental disturbance. We then focus on one important aspect of conservation: how free-living populations respond to human disturbance, particularly in relation to ecotourism. Breeding adult Magellanic penguins, Spheniscus magellanicus, appear to habituate well to tourists, and breed in an area where about 70,000 people visit during the season. Baseline levels of corticosterone return to normal after exposure of naïve birds to humans. However, penguin chicks appear to show a heightened adrenocortical response to handling stress in nests exposed to tourists, compared to chicks living in areas isolated from human intrusions. Given that developmental exposure to stress can have profound influences on how individuals cope with stress as adults, this potential effect of tourists on chicks could have long-term consequences. This field endocrine approach identified a stressor not observed through monitoring behavior alone.

Egg Neglect in the Procellariiformes: Reproductive Adaptations in the Fork-Tailed Storm-Petrel

The eggs of many procellariiform birds may still hatch even though temporarily abandoned during the incubation period. Distant foraging and long incubation periods, characteristic of these birds, increase the probability that storms or undependable food resources will delay an individuals returning to relieve its incubating partner. Consequently, tolerance to chilling by the embryo has evolved to a greater degree in the Procellariiformes than in other orders. This paper reports the incidence of egg neglect in the Fork-tailed Storm-Petrel (Oceanodroma furcata), and discusses the adaptive significance and costs of egg neglect in the Procellariiformes.

Breeding patterns of galapagos penguins as an indicator of oceanographic conditions.

Surface water changes associated with El Ni�o have been known to affect deleteriously top carnivores along coastal South America. Data on the breeding strategies of Gal�pagos penguins and other seabirds indicate that the biological effects of El Ni�o extend much farther west. The breeding biology of these seabirds is adapted to frequent changes in productivity which are associated with El Ni�o.

NEST-SITE CHARACTERISTICS AND REPRODUCTIVE SUCCESS IN MAGELLANIC PENGUINS (SPHENISCUS MAGELLANICUS)

We used cross-sectional, longitudinal, and experimental data to investigate the effects of habitat at the smallest spatial scale-the nest site-on reproductive success of Magellanic Penguins (Spheniscus magellanicus). Over an eight-year period, the amount of nest cover was positively correlated with fledging success. The same pairs tended to be more successful when they had more nest cover, and experimental increases and decreases in cov- er significantly affected survival of nest contents. Other characteristics of nest sites, such as nest type and type of vegetation over the nest, did not affect success. The positive effect of cover resulted mainly from reduced exposure of nest contents to predators during incuba- tion and to high temperatures when chicks were young. Roof cover was positively correlated with fledging success in nests from all areas. Cover on the sides of the nest giving the most protection from the sun was positively correlated with fledging success in warmer sites and with survival of young chicks in all areas. Young chicks at nests with less cover were more likely to move from their nests and to die on hot days. Experimental results indicated that the likelihood of egg detection by predators decreased with increasing nest cover. Height of nest entrance was a significant predictor of egg loss, suggesting that accessibility of nest contents to predators was an important component of predation risk. Thermal properties of nests and risk of predation were related; predation of nest contents was more likely when adults were absent, and during hot weather adults were more often absent from nests with little cover. Although the effect of cover on success was small relative to the large yearly variation in success due to food conditions, cover is likely to influence lifetime reproductive success substantially. Large and long-term data sets and experimental approaches may be necessary to identify subtle but biologically important factors among long-lived organisms that inhabit variable environments. Received 18 November 1996, accepted 29 May 1997.

The adrenocortical response to stress in incubating magellanic penguins (Spheniscus magellanicus)

Circulating levels of glucocorticoids increase rapidly in response to capture and handling in many vertebrate species, which is indicative of the sensitivity of the hy- pothalamo-pituitary-adrenal axis to a variety of acutely stressful events. We measured cir- culating levels of corticosterone at capture and after 25 min of handling and restraint in free- living Magellanic Penguins (Spheniscus magellanicus) during their first two long incubation turns. Initial levels of corticosterone were higher for males than for females; however, levels of corticosterone after 25 min of handling and restraint increased throughout incubation and were higher for females than for males. These 25-min levels of corticosterone were negatively correlated with body mass and body condition. Initial levels of circulating corticosterone, however, were not associated with mass and did not change during the fast, except for an increase among three females that had been incubating the longest. The higher 25-min cor- ticosterone levels for females may be due to their lower body mass and longer fast during incubation. Magellanic Penguins appear to be more responsive to stress as fasting proceeds, suggesting that disturbances should be minimized when penguins have depleted fat stores.

A COMPREHENSIVE REVIEW OF ENDANGERED SPECIES ACT RECOVERY PLANS

Endangered Species Act recovery plans have come under increased scrutiny in both political and academic arenas as species are continually added to the endangered species list but few are removed. To promote more effective recovery planning, the Society for Conservation Biology, in partnership with the U.S. Fish and Wildlife Service and the National Center for Ecological Analysis and Synthesis, sponsored a collaborative project among 19 universities to systematically review a large representative sample of recovery plans. The primary goals of the project were to gather data about the content and characteristics of each sampled recovery plan; to analyze these data to identify important differences, patterns, and trends among the population of plans; and to use these results to inform recommendations for how the recovery planning process could be improved. We developed and used a detailed data collection Instrument to consider and characterize specific attributes of each sampled recovery plan. Topics covered...

Age and Food Deprivation Affects Expression of the Glucocorticosteroid Stress Response in Magellanic Penguin (Spheniscus magellanicus) Chicks

We examined how the glucocortical stress response in free‐living Magellanic penguin (Spheniscus magellanicus) chicks changes with age and whether adrenocortical function of chicks within a brood varies in relation to food provisioned by adults. Chicks showed little corticosterone response to capture stress shortly after hatching, an intermediate response around 45‐d posthatch, and a robust stress response near fledging. However, in response to an adrenocorticotropic hormone (ACTH) challenge, hatchlings were capable of secreting corticosterone at adult‐like levels. The larger sibling in broods of two showed a similar gradual stress‐response development pattern. In contrast, by day 45, when differences in body condition were well established between siblings, the smaller, food‐deprived chicks significantly increased baseline levels of corticosterone but showed normal stress‐induced levels. Near fledging, baseline levels had returned to normal, but stress‐induced levels were lower than expected. Similar to altricial species, normally developing semialtricial Magellanic penguin chicks do not express a robust corticosterone stress response until near fledging. Chronic stressors such as food deprivation cause corticosterone use to be up‐regulated earlier than expected. However, in cases of extended chronic stress, down‐regulation may ensue, thus avoiding the negative effects of chronically elevated levels of corticosterone.