Electric Fencing as a Measure to Reduce Moose-Vehicle Collisions

Abstract: We tested the effectiveness of electric fences to reduce moose (Alces alces)-vehicle collisions in 2 fenced sectors (5 km and 10 km) using weekly track surveys and Global Positioning System telemetry. Number of moose tracks along highways decreased by approximately 80% following fence installation. Only 30% (16/53) of moose tracks observed on the road side of the fence were left by moose that crossed an operational fence; moose mostly entered the fenced corridor through openings (e.g., secondary roads) or at fence extremities. Electric fences also prevented 78% (7/9) of collared moose from crossing the highway in fenced sectors. Fences were less effective during occasional power failures. We suggest that circuit breakers should be used to prevent power failures and that there should be no opening along the fence line unless anti-ungulate structures are used.     

Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

1. Peatlands have suffered great losses following drainage for agriculture, forestry, urbanisation, or peat mining, near inhabited areas. We evaluated the faunal and vegetation patterns after restoration of a peatland formerly mined for peat. We assessed whether bog pools created during restoration are similar to natural bog pools in terms of water chemistry, vegetation structure and composition, as well as amphibian and arthropod occurrence patterns. 2. Both avian species richness and peatland vegetation cover at the site increased following restoration. Within bog pools, however, the vegetation composition differed between natural and man‐made pools. The cover of low shrubs, Sphagnum moss, submerged, emergent and floating vegetation in man‐made pools was lower than in natural pools, whereas pH was higher than in typical bog pools. Dominant plant species also differed between man‐made and natural pools. 3. Amphibian tadpoles, juveniles and adults occurred more often in man‐made pools than natural bog pools. Although some arthropods, including Coleoptera bog specialists, readily colonised the pools, their abundance was two to 26 times lower than in natural bog pools. Plant introduction in bog pools, at the stocking densities we applied, had no effect on the occurrence of most groups. 4. We conclude that our restoration efforts were partially successful. Peatland‐wide vegetation patterns following restoration mimicked those of natural peatlands, but 4 years were not sufficient for man‐made pools to fully emulate the characteristics of natural bog pools.     

Variations in bird abundance in tropical arid and semi-arid habitats

Temporal variation in bird abundance was studied during a complete annual cycle in a thorn scrub, a thorn woodland and a deciduous forest in northeastern Venezuela. Abundance of site-attached and transient birds from different feeding guilds was determined by mist-netting at 2-week intervals. Diets were investigated by regurgitated samples. The overall avifauna was characterized by a low number of species but they were present all year despite showing strong seasonal fluctuations in abundance. The number of bird species and individuals peaked before and after the reproductive period. These high values probably were associated with movement of species feeding on plant food during the late dry season and the post-breeding dispersion of juveniles. Bird richness and abundance were lowest during the breeding season and in the early dry season when food abundance was low. Birds from different feeding guilds showed distinct patterns of seasonal abundance which tended to be similar at all three sites. Transient birds represented a large portion of the avifauna, particularly in nectarivores, frugivores and granivores during the dry season. We used a canonical correspondence analysis to demonstrate that bird abundance was correlated with breeding activity, rainfall seasonality and food abundance, with the influence of each parameter varying according to feeding guilds, spatial behaviour of individuals and habitats. Despite a great turnover in the occurrence of the diverse food types available, species composition remained strikingly constant during the year, with birds responding to seasonal changes primarily through a generalist feeding habit and a highly variable rate of transience.     

Evolutionary influences on body size in free-living and parasitic isopods

The influence of mode of life and habitat characteristics on the evolution of body size in isopods was investigated in a comparative analysis based on data from 746 free-living and parasitic species. The phylogeny of isopods allowed 24 independent comparisons to be made between higher taxa (families or superfamilies), each corresponding to a separate branching event. The evolution of parasitism was consistently associated with reductions in body size. On the contrary, invasion of freshwater habitats was consistently coupled with increases in body size. Lineages moving to higher latitudes were significantly more likely to evolve larger body sizes than those shifting toward the equator. In addition, colonizing deeper water resulted in a weak tendency to evolve larger body size. The analysis suggests that the large size of some isopod groups parasitic on fish (e.g. Cymothoidae) may have been inherited from a free-living ancestor and is not the product of directional selection toward large size and greater fecundity.     

Investing in attachment: evolution of anchoring structures in acanthocephalan parasites

Secure attachment to host tissues is essential for survival and reproduction in parasitic organisms. The production of elaborate attachment structures must be costly, however, and investments in attachment should be approximately proportional to the likelihood that a parasite will be dislodged. In the present study, relative investments in attachment as a function of body size and the type of host used were examined across 138 species of acanthocephalans. These worms live anchored to the intestinal wall of a vertebrate host by inserting their hooked proboscis into host tissues. Taking proboscis volume into account, there is a negative interspecific relationship between the number of hooks borne on the proboscis and their mean length, reflecting a trade‐off between hook number and hook length. This supports the assumption that hooks are costly to produce, because any given species cannot simultaneously maximize both the relative number and relative length of the hooks it produces. There is a positive relationship between total worm size and total hook length, but it is weak, with a slope indicating that, as total body volume increases, total hook length also increases but at a slower rate. Indeed, relative investments in attachment, measured as hook length per unit body volume, decrease as worm size increases. Independently of total body size, investments in hook production are higher in species exploiting endothermic hosts, especially birds, than in those living in ectothermic hosts. Given the greater amounts of food passing through the gut of endotherms, and the richer and denser communities of intestinal parasites that they harbour, they are likely to select for greater investments in attachment. These results support the prediction that investments in attachment are influenced by the probability of being dislodged, and allow comparisons with other groups of intestinal parasites such as cestodes or trematodes. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 637–645.     

Genetic diversity and insular colonization of Liolaemus pictus (Squamata,Liolaeminae) in north‐western Patagonia

The Chilotan Archipelago and surrounding areas of north‐western Patagonia (41°–43°S, 72°–74°W) offer a unique opportunity to study the interplay between the recent genetic and paleoenvironmental evolution on temperate rainforest environments. Previous studies in this region have postulated that land biota persisted west of the Patagonian ice sheet, in ice‐free low‐elevation regions of the mainland, and the north‐western portion of Isla Grande de Chiloé during Quaternary ice ages. In this study, we analysed the phylogeographical structure (Cytochrome b) of the iguanid lizard Liolaemus pictus to estimate their genetic structure in response to glacial–interglacial cycles and colonization routes. We found that populations from the mainland and Isla Grande de Chiloé do not share haplotypes and, thus, are divergent haplogroups. This divergence might reflect an ancient isolation, much older than the last glaciation. Moreover, the existence of four divergent haplogroups among L. pictus populations in the mainland suggests the persistence of multiple isolated populations during the last glaciation. Our results also indicate that the colonization of small islands occurred from several source sites, located both in the mainland and in Isla Grande de Chiloé, after the Last Glacial Maximum.     

Microsatellite loci for the New Zealand trematode Maritrema novaezealandensis

Seven polymorphic microsatellite loci were isolated and characterized from the coastal New Zealand trematode Maritrema novaezealandensis, an important driving force in the population dynamics of its snail and crustacean intermediate hosts. Observed heterozygosities ranged from 0.33 to 0.82, and three to 17 alleles were detected in 22 trematode sporocysts. These loci will be integral for identifying parasite genetic clones within hosts and addressing a range of questions concerning the molecular ecology of this species.     

Has the introduction of brown trout altered disease patterns in native New Zealand fish?

1. It is well recognised that non-indigenous species (NIS) can affect native communities via the 'spillover' of introduced parasites. However, two other potentially important processes, the 'spillback' of native parasites from a competent NIS host, where the latter acts as a reservoir leading to amplified infection in native hosts, and the 'dilution' of parasitism by a NIS host acting as a sink for native parasites, have either not been tested or largely overlooked.
2. We surveyed the helminth parasite fauna of native New Zealand fish in Otago streams that varied in the abundance of introduced brown trout Salmo trutta , to look for evidence of spillback and/or dilution. Spillover is not an issue in this system, with trout introduced as parasite-free eggs.
3. Seven native parasite species were present across 12 sites; significant inverse relationships with an index of trout abundance (i.e. dilution) were documented for three species infecting the native upland bully Gobiomorphus breviceps , and one species infecting the native roundhead galaxias Galaxias anomalus .
4. An inverse relationship between bully energy status and infection intensity of one parasite species suggests that parasite dilution could have positive effects on bully populations. Our failure to detect similar relationships for the other parasites does not preclude the possibility that dilution is beneficial to native fish, since parasites may have subtle or unmeasured impacts.
5. The parasite dilution patterns reported are compelling in that they occurred across several native host and parasite species; as such they have important implications for invasion ecology, providing an interesting contrast to the largely negative impacts reported for NIS. Mechanisms potentially responsible for the patterns observed are discussed.     

Management of Roadside Salt Pools to Reduce Moose-Vehicle Collisions

ABSTRACT Wildlife-vehicle collisions cause numerous human fatalities and injuries, and generate considerable expenses in property damage each year. Certain characteristics of the road and its surroundings are known to have an impact on collision probability. Roadside salt pools increase the risk of collision by attracting moose (Alces alces) to the side of the road. In the Laurentides Wildlife Reserve of Québec, Canada, roadside salt pools were drained and filled with rocks to deter moose from drinking. We surveyed 12 roadside salt pools during 3 consecutive summers (2003–2005) from mid-May to mid-August. Seven salt pools were managed in autumn 2004, and 5 pools were left untreated. We equipped all 12 sites with electronic apparatus that allowed us to detect moose attendance and study their behavior. We also measured physical, chemical, and environmental characteristics of these pools and other unvisited pools in order to correlate moose attendance with specific habitat criteria. We found that moose mostly attended roadside salt pools from mid-June to mid-July, with a decrease in August. Moose attendance was significantly correlated with visual obstruction toward the road and water availability. Management of the pools caused a decrease in mean length of time moose spent at them. Number of visits decreased significantly at night (by 90%), which was when most visits occurred, but not during the day. The proposed management practice prevented all visiting moose from drinking brackish water. These results suggest that moose should eventually lose interest in treated salt pools, therefore decreasing the risk of moose-vehicle collisions on the road.     

Moose Movement Rates Along Highways and Crossing Probability Models

ABSTRACT We developed and validated a density-adjusted spatial model to predict moose (Alces alces) highway-crossing probability to see if the model could be used as an index of moose-vehicle collision risk. We installed Global Positioning System telemetry collars on 47 moose in the north of the Laurentides Wildlife Reserve, Québec, for 2–36 months. We recorded only 84 highway crossings in spring (0.29% of 28,967 2-hr steps) and 122 crossings in summer (0.18% of 68,337 2-hr steps), despite a high sampling effort and having captured moose close to highways. Moose movement rates during movement steps crossing a highway were on average 3 times higher than during the steps preceding or following highway crossing. Paths used by moose when crossing a highway were characterized by a high proportion of food stands, low proportion of lakes and rivers, and topography typical of a valley. Highway-crossing sites were located in valleys with brackish pools and forest stands providing coniferous cover but a low proportion of lakes and rivers. We adjusted moose crossing probability for local variation in moose density using aerial survey data and assessed crossing probability along the highways in the entire Laurentides Wildlife Reserve. We tested the model using moose-vehicle accident data from 1990 to 2002. The relationship between the density-adjusted crossing probability and number of accidents was relatively loose at the 1-km scale but improved markedly when using longer highway sections (5–15 km; r > 0.80). Our results demonstrate that roads and their surroundings are perceived as low-quality habitat by moose. We also conclude that road segments installed along secondary valleys could be a highly strategic site to deploy mitigation measures such as fences and that it could be desirable to increase the width of road shoulders to reduce forest cover and to eliminate brackish pools to reduce cervid-vehicle collisions. We suggest using empirical data such as location of vehicle-wildlife collisions to plan mitigation measures at a fine scale.