Ethylene limits abscisic acid‐ or soil drying‐induced stomatal closure in aged wheat leaves

The mechanism of age‐induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA‐ or soil drying‐induced stomatal closure of older leaves was partly restored by pretreating plants with 1‐methylcyclopropene (1‐MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C‐2, which contains 1‐aminocyclopropane‐1‐carboxylic acid (ACC)‐deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water‐use efficiency.     

Anthropogenic changes to the landscape resulted in colonization of koalas in north‐east New South Wales,Australia

Significant changes in the distribution and persistence of species have been driven by Pleistocene cyclical climate changes and, more recently, by human modification of the environment. In eastern Australia, Pleistocene cyclical patterns in temperature and aridity led to the expansion and retraction of rainforest and likely affected the distribution of the koala (Phascolarctos cinereus, family Phascolarctidae), a species preferring dry or open woodland. More recently, anthropogenic landscape modification has led to a large‐scale change in distribution of the koala following the destruction of approx. 75 000 ha of subtropical rainforest in north‐east New South Wales termed the ‘Big Scrub’. Sharing of the control region haplotypes to the north and south of this region indicate historical connectivity of coastal koala populations. However, the majority (110/115) of sampled koalas from this region shared a single mitochondrial control region haplotype, suggesting that koalas did not persist in multiple refugial pockets within a heterogenous rainforest but expanded into the region following deforestation. Bayesian cluster analysis of microsatellite data consistently identified two clusters of koalas. One cluster, in the north of the area, had high microsatellite diversity (10 alleles per locus, He = 0.79) and clustered with koalas further to the north, thus suggesting a southerly expansion into the cleared area. To the south was a cluster with significantly lower diversity (six alleles per locus, He = 0.59, P < 0.001). It is possible there has been restricted or filtered movement of koalas between these clusters, which coincides with a cleared river valley and associated roads or immigration from populations both to the north and to the south. This study gives an insight into the timescale of changes in species distribution following rapid alterations to suitable habitat.     

Wind Energy Development and Wildlife Conservation: Challenges and Opportunities

ABSTRACT Wind energy development represents significant challenges and opportunities in contemporary wildlife management. Such challenges include the large size and extensive placement of turbines that may represent potential hazards to birds and bats. However, the associated infrastructure required to support an array of turbines—such as roads and transmission lines—represents an even larger potential threat to wildlife than the turbines themselves because such infrastructure can result in extensive habitat fragmentation and can provide avenues for invasion by exotic species. There are numerous conceptual research opportunities that pertain to issues such as identifying the best and worst placement of sites for turbines that will minimize impacts on birds and bats. Unfortunately, to date very little research of this type has appeared in the peer-reviewed scientific literature; much of it exists in the form of unpublished reports and other forms of gray literature. In this paper, we summarize what is known about the potential impacts of wind farms on wildlife and identify a 3-part hierarchical approach to use the scientific method to assess these impacts. The Lower Gulf Coast (LGC) of Texas, USA, is a region currently identified as having a potentially negative impact on migratory birds and bats, with respect to wind farm development. This area is also a region of vast importance to wildlife from the standpoint of native diversity, nature tourism, and opportunities for recreational hunting. We thus use some of the emergent issues related to wind farm development in the LGC—such as siting turbines on cropland sites as opposed to on native rangelands—to illustrate the kinds of challenges and opportunities that wildlife managers must face as we balance our demand for sustainable energy with the need to conserve and sustain bird migration routes and corridors, native vertebrates, and the habitats that support them.     

NEW CLADID AND FLEXIBLE CRINOIDS FROM THE MISSISSIPPIAN (TOURNAISIAN, IVORIAN) OF ENGLAND AND WALES

Abstract:  The modern study of fossil crinoids began with J. S. Miller who, in 1821, described specimens from southern England, nearby Wales and other regions, and named several common Early Carboniferous genera. Later, in 1950–60, James Wright monographed all known Early Carboniferous crinoids from the British Isles. In spite of such previous scrutiny, we recognize here two new genera among species already described: Glamorganocrinus gen. nov. (type species: Ophiurocrinus gowerensis Wright, 1960) from South Wales and Mendipocrinus gen. nov. (type species: Poteriocrinus latifrons Austin and Austin, 1847) from southern England. These new genera increase the number of advanced cladid genera in the Ivorian Substage of the Tournaisian in western Europe to 18, and the total number of crinoid genera to 36. A review of species assigned to Mespilocrinus has led to the recognition of M. granulifer De Koninck and LeHon, 1854 as a nomen dubium. A new species of Mespilocrinus , M. wrighti sp. nov., is described from the Ivorian of South Wales; this is the most highly derived species of the genus, as based on a phylogenetic analysis including ten species and 13 characters, with Pycnosaccus as the outgroup. A single, well-ordered tree resulted from this analysis. Interpretation of this tree suggests that the centre of evolution for Mespilocrinus was North America, where three species appeared during the Kinderhookian (early Tournaisian), rapidly achieving morphological disparity within the genus. This radiation event was part of the overall explosive radiation of crinoids following the Late Devonian mass extinction event when crinoid diversity was at a global minimum during the Frasnian. Recovery began during the Famennian, followed by an explosive radiation in the Tournaisian.     

Estimates of Survival from Radiotelemetry: a Response to Guthery and Lusk

Abstract: Radiotelemetry has become an important and frequently used tool in wildlife research. Inferences drawn from radiotelemetry data depend on the assumption that the radiotransmitters are not influencing parameter(s) of interest. An article by Guthery and Lusk (2004) in the Wildlife Society Bulletin questioned the validity of this assumption for estimating survival rates of northern bobwhites (Colinus virginianus) using radiotelemetry data. In this evaluation, we address technical and philosophical flaws in Guthery and Lusk's (2004) critique of northern bobwhite studies utilizing radiotelemetry. They concluded that biologists should be skeptical of radiotelemetry studies and they advised researchers to design studies to address potential biases caused by radiotransmitters using independent data. Although we agree that researchers are responsible for testing key assumptions of their techniques, we believe Guthery and Lusk's (2004) conclusions were not well supported and were based on tenuous assumptions. Guthery and Lusk (2004) calculated the level of productivity (given as a fall age ratio) required to balance a simple population model that contained published estimates of annual survival and assumed an annual finite population growth rate of 1.0. We review their population model and show that the relationship between an annual survival rate and fall age ratio is nonlinear. This nonlinearity can lead to biased estimates of a fall age ratio, especially at lower values of annual survival. We also question the validity of using fall age ratios as an estimator of productivity. Further, we suggest that this assessment of a radiotransmitter effect from a survival rate itself is not appropriate. This rate can be depressed (or elevated) for a variety of reasons not related to the influence of radiotransmitters. In addition, Guthery and Lusk (2004) assumed that daily survival rates (as calculated from both annual and seasonal published estimates) were constant throughout the year; thus, they scaled daily survival rates from seasonal to annual estimates. Further, their meta-analysis was hindered by temporal pseudoreplication and a lack of independence among the observations used in the analysis. We conclude the weight of the evidence presented by Guthery and Lusk (2004) is not as strong as they claim because it fails to meet the test of sufficient causation. While scientists should always be skeptical and critical of assumptions of all methods employed in wildlife research, more rigorous tests are necessary before we discredit a valuable technique without sufficient empirical evidence.     

Reduction and Maintenance of a White-Tailed Deer Herd in Central Massachusetts

Abstract: Controlled public hunts have been used in a variety of settings to reduce overabundant white-tailed deer (Odocoileus virginianus) herds. We present the results of a large-scale (160 km²) controlled hunt at Quabbin Reservation (QR) in central Massachusetts, USA. The QR was divided into 5 hunt zones. Hunting was initiated in each zone from 1991 to 1994 and continued through 2004. The management goal was to achieve posthunt deer densities of4 deer/km². Initial estimated deer densities in each zone ranged from 11.4 deer/km² to 27.6 deer/km². The management goals were reached in each zone after 2-4 years of hunting. Posthunt populations were maintained at or below the goal even though total hunter effort was reduced. Hunters were not required to harvest antlerless deer, but antlerless deer comprised 55-83% of the harvest each year. We simulated the effects of 5 years without hunting on deer populations. The simulated deer population exceeded management goals after 2 years. Our results demonstrate that controlled public deer hunts can effectively reduce deer populations and maintain them at desired levels over large areas with minimal hunter restrictions. Managers should prepare stakeholders during the hunt planning process for the need to continue overall harvest rates of >30% during the maintenance phase of a deer management program.     

Species responses of colonising beetles to variation in patch quality,number, and context in experimental aquatic landscapes

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Plasticity of functional traits varies clinally along a rainfall gradient in Eucalyptus tricarpa

Widespread species often occur across a range of climatic conditions, through a combination of local genetic adaptations and phenotypic plasticity. Species with greater phenotypic plasticity are likely to be better positioned to cope with rapid anthropogenic climate changes, while those displaying strong local adaptations might benefit from translocations to assist the movement of adaptive genes as the climate changes. Eucalyptus tricarpa occurs across a climatic gradient in south‐eastern Australia, a region of increasing aridity, and we hypothesized that this species would display local adaptation to climate. We measured morphological and physiological traits reflecting climate responses in nine provenances from sites of 460 to 1040 mm annual rainfall, in their natural habitat and in common gardens near each end of the gradient. Local adaptation was evident in functional traits and differential growth rates in the common gardens. Some traits displayed complex combinations of plasticity and genetic divergence among provenances, including clinal variation in plasticity itself. Provenances from drier locations were more plastic in leaf thickness, whereas leaf size was more plastic in provenances from higher rainfall locations. Leaf density and stomatal physiology (as indicated by δ¹³C and δ¹⁸O) were highly and uniformly plastic. In addition to variation in mean trait values, genetic variation in trait plasticity may play a role in climate adaptation.