Breeding Site Selection Research Articles

Kin‐bias, breeding site selection and female fitness in a cannibalistic Neotropical frog

Resource availability influences sexual selection within populations and determines whether behaviours such as territoriality or resource sharing are adaptive. In Thoropa taophora, a frog endemic to the Atlantic Coastal Rainforest of Brazil, males compete for and defend limited breeding sites while females often share breeding sites with other females; however, sharing breeding sites may involve costs due to cannibalism by conspecific tadpoles. We studied a breeding population of T. taophora to determine (i) whether this species exhibits polygynous mating involving female choice for territorial males and limited breeding resources; (ii) whether limited breeding resources create the potential for male-male cooperation in defence of neighbouring territories; and (iii) whether females sharing breeding sites exhibit kin-biased breeding site choice, possibly driven by fitness losses due to cannibalism among offspring of females sharing sites. We used microsatellites to reconstruct parentage and quantify relatedness at eight breeding sites in our focal population, where these sites are scarce, and in a second population, where sites are abundant. We found that at localities where the appropriate sites for reproduction are spatially limited, the mating system for this species is polygynous, with typically two females sharing a breeding site with a male. We also found that females exhibit negative kin-bias in their choice of breeding sites, potentially to maximize their inclusive fitness by avoiding tadpole cannibalism of highly related kin. Our results indicate that male territorial defence and female site sharing are likely important components of this mating system, and we propose that kinship-dependent avoidance in mating strategies may be more general than previously realized.

Using Satellite and Airborne LiDAR to Model Woodpecker Habitat Occupancy at the Landscape Scale

Incorporating vertical vegetation structure into models of animal distributions can improve understanding of the patterns and processes governing habitat selection. LiDAR can provide such structural information, but these data are typically collected via aircraft and thus are limited in spatial extent. Our objective was to explore the utility of satellite-based LiDAR data from the Geoscience Laser Altimeter System (GLAS) relative to airborne-based LiDAR to model the north Idaho breeding distribution of a forest-dependent ecosystem engineer, the Red-naped sapsucker (Sphyrapicus nuchalis). GLAS data occurred within ca. 64 m diameter ellipses spaced a minimum of 172 m apart, and all occupancy analyses were confined to this grain scale. Using a hierarchical approach, we modeled Red-naped sapsucker occupancy as a function of LiDAR metrics derived from both platforms. Occupancy models based on satellite data were weak, possibly because the data within the GLAS ellipse did not fully represent habitat characteristics important for this species. The most important structural variables influencing Red-naped Sapsucker breeding site selection based on airborne LiDAR data included foliage height diversity, the distance between major strata in the canopy vertical profile, and the vegetation density near the ground. These characteristics are consistent with the diversity of foraging activities exhibited by this species. To our knowledge, this study represents the first to examine the utility of satellite-based LiDAR to model animal distributions. The large area of each GLAS ellipse and the non-contiguous nature of GLAS data may pose significant challenges for wildlife distribution modeling; nevertheless these data can provide useful information on ecosystem vertical structure, particularly in areas of gentle terrain. Additional work is thus warranted to utilize LiDAR datasets collected from both airborne and past and future satellite platforms (e.g. GLAS, and the planned IceSAT2 mission) with the goal of improving wildlife modeling for more locations across the globe.

Differences in dispersal- and colonization-related traits between taxa from the freshwater and the terrestrial realm

The aquatic and terrestrial realms differ in many physical properties that not only require specific physiological adaptations but also cause differences in dispersal options. We thus expect that life-history traits related to dispersal and colonization are under selection pressure because freshwater habitats are more isolated and thus more difficult to reach. We compared traits from European databases of three taxonomic groups along the passive–active dispersal gradient: plants (Plantes), snails (Mollusca: Gastropoda: Prosobranchia et Pulmonata) and hoverflies (Diptera: Syrphidae), all of which have both terrestrial and freshwater species (plants and snails) or early life stages (hoverflies). Aquatic taxa seem to be more successful long-distance dispersers than are terrestrial taxa. Our analysis also revealed lower numbers of seeds or eggs produced in the aquatic habitats. However, aquatic taxa often allocate resources to offspring guarding (vegetative propagules in plants, egg capsules in snails) and breeding-site selection (syrphids). Colonization of the aquatic realm is reinforced by increases in life span (plants), clonal spread (plants), shorter generation times (snails), selfing ability (marginal effect in pulmonate snails) or paedogenesis (two incidences in hoverflies, needs further studies). Probably, the variety of strategies reflects the different evolutionary backgrounds that elicit different combinations of trade-offs, but all traits also might increase invasibility of species.

Slipping through the Cracks: Rubber Plantation Is Unsuitable Breeding Habitat for Frogs in Xishuangbanna, China

Conversion of tropical forests into agriculture may present a serious risk to amphibian diversity if amphibians are not able to use agricultural areas as habitat. Recently, in Xishuangbanna Prefecture, Yunnan Province – a hotspot of frog diversity within China – two-thirds of the native tropical rainforests have been converted into rubber plantation agriculture. We conducted surveys and experiments to quantify habitat use for breeding and non-breeding life history activities of the native frog species in rainforest, rubber plantation and other human impacted sites. Rubber plantation sites had the lowest species richness in our non-breeding habitat surveys and no species used rubber plantation sites as breeding habitat. The absence of breeding was likely not due to intrinsic properties of the rubber plantation pools, as our experiments indicated that rubber plantation pools were suitable for tadpole growth and development. Rather, the absence of breeding in the rubber plantation was likely due to a misalignment of breeding and non-breeding habitat preferences. Analyses of our breeding surveys showed that percent canopy cover over pools was the strongest environmental variable influencing breeding site selection, with species exhibiting preferences for pools under both high and low canopy cover. Although rubber plantation pools had high canopy cover, the only species that bred in high canopy cover sites used the rainforest for both non-breeding and breeding activities, completing their entire life cycle in the rainforest. Conversely, the species that did use the rubber plantation for non-breeding habitat preferred to breed in low canopy sites, also avoiding breeding in the rubber plantation. Rubber plantations are likely an intermediate habitat type that ‘slips through the cracks’ of species habitat preferences and is thus avoided for breeding. In summary, unlike the rainforests they replaced, rubber plantations alone may not be able to support frog populations.

Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa

Badu-Apraku, B., Akinwale, R. O., Obeng-antwi, K., Haruna, A., Kanton, R., Usman, I., Ado, S. G., Coulibaly, N., Yallou, G. C. and Oyekunle, M. 2013. Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa. Can. J. Plant Sci. 93: 699–714. The selection of suitable breeding and testing sites is crucial to the success of a maize (Zea mays L.) improvement programme. Twelve early-maturing maize cultivars were evaluated for 3 yr at 16 locations in West Africa to determine the representativeness, discriminating ability, and repeatability of the testing sites and to identify core testing sites. Genotype main effect plus genotype by environment interaction (GGE) biplot analysis revealed that Zaria (Nigeria), Nyankpala (Ghana), and Ejura (Ghana) displayed the highest discriminating ability. Two mega-environments were identified. Bagou, Nyankpala, Bagauda, Ikenne, and Mokwa constituted the first mega-environment (ME1); Ejura, Ina and Sotuba represented the second (ME2). The ME1 would be more useful for evaluating early maize genotypes for tolerance to drought than ME2 because locations in ME1 were more strongly correlated to Ikenne (managed drought stress site). Among the test locations, Bagou and Mokwa were found to be closely related to Ikenne in their ranking of the cultivars for drought tolerance; Zaria was the exact opposite, indicating that this was the least suitable location for evaluating genotypes for drought tolerance. Nyankpala and Ikenne were identified as the core testing sites for ME1 and Ejura for ME2. TZE Comp 3 C2F2 was identified as the highest yielding cultivar for ME1 and Syn DTE STR-Y for ME2, indicating that they could be used as check cultivars. Ikenne, Nyankpala, and Ejura had moderately high repeatability. They were closer to the average environment axis of each mega-environment and will be useful for culling unstable genotypes during multi-locational testing. Other sites were less representative and not repeatable and will not be useful for evaluating early maize cultivars for drought tolerance.

Differential response to abiotic conditions, predation risk, and competition determine breeding site selection by two anuran species

Sympatry of species has been a central debate in ecology for decades but the mechanisms that allow coexistence are still heatedly disputed. The main paradigms include the importance of abiotic conditions, predation risk, and competition as determinants of community structure. In this study, we investigated oviposition-site selection of two anuran species, Asiatic toads (Bufo gargarizans) and dark-spotted frogs (Pelophylax nigromaculata), which coexist in southwestern China. We sampled the abiotic and biotic attributes of 36 B. gargarizans breeding sites and 34 adjacent unused sites, and 30 P. Nigromaculata spawning sites and 36 nearby unused sites. Our results showed that these two anuran species differed in the use of the main habitat types. B. gargarizans selected larger spawning sites with low levels of disturbance, high dissolved oxygen content, and the presence of fish. Conversely, P. nigromaculata preferred smaller waterbodies that were shallow, clear, and free of fish and B. gargarizans tadpoles. We conclude that differential habitat use and differences in response to abiotic conditions, predation risk, and competition, contributes to facilitating local coexistence and high species diversity in pond communities.

Breeding-Site Selection By Ferruginous Hawks Within Utah's Uintah Basin

We examined factors that might influence breeding-site selection in Ferruginous Hawks (Buteo regalis) in the Uintah Basin, Utah, an area undergoing rapid oil and gas development. We located 31 occupied nests of Ferruginous Hawk (10 during 2002, 10 during 2003, and 11 during 2004) and compared them to 32 historical nest sites of Ferruginous Hawks that were unoccupied during our study, and 32 random sites. Ferruginous Hawks selected nesting areas that were dominated by mixed desert-shrub vegetation communities with scattered Utah juniper trees (Juniperus osteosperma), higher prey abundance, and a high number of active petroleum wells. Within occupied territories, Ferruginous Hawks selected nest sites in juniper trees, on cliff ledges, or on rock pinnacles that occurred in areas with higher prey abundance, close to an active well, and within 2–3.5 km of the nearest occupied nest of another raptor. The counterintuitive association between nesting activity and oil development may be the result of: (1) a spurious relationship between the occurrence of oil and gas reserves and suitable breeding habitat, (2) a time lag in the response of nesting pairs to development, or (3) oil and gas developments indirectly benefiting nesting pairs by improving the habitat of prey species and subsequently increasing prey densities, and/or reducing the threat of predation to Ferruginous Hawks or their young.

Environmental factors fail to explain oviposition site use in the European common frog

AbstractA 7‐year monitoring of potential oviposition ponds of the European common frog Rana temporaria, in northern Bavaria, Germany, indicated that breeding ponds were not randomly used. Site fidelity could not consistently explain this pattern. Because amphibians are known to select oviposition sites according to certain habitat characteristics, we investigated pond parameters that may drive breeding site selection in that area. We recorded 44 abiotic and biotic parameters, including variables within‐ponds, predator presence, as well as habitat characteristics of the terrestrial area surrounding the ponds. However, multifactorial statistics such as non‐metric multidimensional scaling, hierarchical clustering and random forest algorithm as well as single‐factor comparisons could not highlight common habitat features of chosen ponds. The results of this study indicate that breeding site choice is more than a pure function of habitat characteristics, and that understanding the reproductive biology, even of such a widespread species as R. temporaria, needs more research effort.

Breeding habitat of red-backed shrike Lanius collurio on farmland hilly areas of Central Italy: is functional heterogeneity one important key?

This paper examines the relationships between breeding site selection of red-backed shrikes Lanius collurio and land-use features using GIS. We examine the habitat preference of this species in areas characterised by a temperate climate and by a prevailing agricultural cover. We focused on the occurrence of red-backed shrike in relation to fragmentation, patch diversity and a few habitat features of the farmlands, as a surrogate for functional heterogeneity. We also studied several parameters such as the number of closely located nests, minimum distance between the nests and elevation above sea level of the breeding sites. Our results confirm the importance of the marginal elements such as shrubs, hedgerows and scatter patches in farmlands, and could add an effective method for studying suitable habitats for L. collurio using few environmental parameters. Our results suggest that breeding sites of the species are located mainly in cultivated zones, characterised by the presence of dispersal shrub patches and high edge density values and in proximity to the roads. Our results confirm also that landscape heterogeneity is one of the key factors in the selection of breeding habitat for red-backed shrikes in farmland of Central Italy, and therefore should be subject to agricultural policies aimed at conservation and maintenance of these environmental features.

No Evidence for Individual Assortment by Temperament Relative to Patch Area or Patch Openness in the Bobolink

Abstract: Recent research has shown repeatable individual variability in temperament traits. We tested the hypotheses that individual Bobolinks (Dolichonyx oryzivorus) vary consistently in their response to predators, a temperament trait, and that this individual variation is associated with breeding-site selection. Specifically, we tested whether measures of behavioral response to human approaches are associated with either patch area or patch openness and thus to area sensitivity. We made two to seven sequential approaches to Bobolinks in 2009 and 2010, measuring starting distance, flight-initiation distance, and the distance from the observers to where the birds landed. We analyzed the data with repeatability estimates and linear mixed modeling. Flight-initiation distance was repeatable when starting distance was controlled for, but distance to landing was not after starting distance and flight-initiation distance were controlled for. We found no strong effect of area or openness on either flight-initi...

The importance of social information in breeding site selection increases with population size in the Eurasian Griffon VultureGyps fulvus

Animals can select breeding sites using non‐social information (habitat characteristics) and social information (conspecific presence or abundance). The availability of both types of information is expected to vary over time during the colonization of a new area, conditioning their use by colonizers. However, if and how both types of information are exploited during the colonization process remains unclear. We hypothesized that non‐social information should be predominant at the beginning of a colonization episode (when conspecific presence is low) and that social information should gain in importance as the colonization progresses. We tested this hypothesis by studying habitat selection by the Griffon VultureGyps fulvus, a long‐lived colonial raptor, during a natural colonization process spanning 40 years. In NW Spain, the population showed a sharp increase from 15 breeding pairs in three colonies in the 1970s to 586 breeding pairs in 120 colonies in 2008, expanding its range from 90 km2in the 1970s to 6403 km2in 2008, with directions of expansion following areas rich in nesting cliffs. The main determinants of habitat selection varied over time. Livestock density and the characteristics of nesting cliffs were the main predictors of settlement at the onset of colonization. Breeding density of conspecifics increased its importance over time, having the greatest relative weight in habitat selection later in the colonization process. Our results indicated a prevalent use of non‐social information during the early stages of the colonization and an increasing role of social information as the expansion progressed.

Mechanisms Underlying the Bioindicator Notion: Spatial Association between Individual Sexual Performance and Community Diversity

The bioindicator notion is an appealing concept that has received more support in applied than in basic ecology, mostly due to the difficulty in deriving general ecological rules applicable to all target organisms. However, recognizing the mechanisms that determine the association between a particular species and the well-being of many other species is important for understanding the functioning of ecosystems and the relationship among different biological levels. We examined here the processes at the individual level that cause an association between species performance and biodiversity value, by analyzing attributes that can be studied in a variety of animals with sexual reproduction, namely breeding site selection and condition-dependent sexual signals. Our study model was the Capercaillie, an indicator of forest functioning and diversity, and the associated bird community, used here as a surrogate of broader forest biodiversity. At a regional scale Capercaillie occurrence was not associated with the most diverse forest patches, but at the scale of male spring territories the sexual display grounds (arenas) were located in the oldest and less disturbed forest portions, which also hosted the richest local bird communities. Social mechanisms and conspecific cueing likely concurred with habitat-driven processes in determining the long-term persistence of traditional display grounds, which were appealing to many other species because of their structural composition. Characteristics of male vocal display that honestly advertize male quality (low frequencies and rapid song rates) were significantly correlated with high diversity values, resulting in a spatial association between individual and community performances. Costly or risky activities such as reproductive or social behaviors, which more than other attributes match gradients in habitat quality, are therefore contributing to functionally connect individuals with ecosystem health.

The semiochemically mediated interactions between bacteria and insects

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect species, inducing particular behaviours, such as the localisation of a source of food, the orientation to an adequate oviposition site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing on the semiochemically mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest management, advances in this field are discussed in the context of biological control against insect pests.

Breeding-site selection by red-belly toads, Melanophryniscus stelzneri (Anura: Bufonidae), in Sierras of Córdoba, Argentina

Abstract Differences among wetlands can have important consequences on reproductive success of amphibians; therefore habitat selection is expected to be of particular importance for anurans inhabiting heterogeneous environments. To investigate if the red-belly toad (Melanophryniscus stelzneri; Anura: Bufonidae) uses available habitats differentially and to determine the main factors influencing the use of certain water bodies as breeding habitat, we surveyed 30 spawning sites used by red-belly toads, and 30 adjacent unused sites, in an area of the Sierras of Córdoba, Argentina. We evaluated the relative importance of morphological and biotic features of ponds, and the presence of other organisms within the water body on the use of ponds as breeding sites by red-belly toads. Eight habitat variables related to important water body features were recorded and were used to fit a habitat selection model with GLM. Red-belly toads presented a positive selection to mallines, a wetland characteristic of the Sierras of Córdoba. They were associated with small, shallow ephemeral ponds with muddy banks and a high percent of vegetation cover. In general, the ponds used did not host other anuran species or potential predators. Breeding site selection by red-belly toads is largely consistent with records for other species of the genus in other parts of Argentina.

The best of a harsh lot in a specialized species: breeding habitat use by the yellow-bellied toad (Bombina variegata) on rocky riverbanks

AbstractBecause of the narrowness of their niches, specialised species are often vulnerable because their populations suffer from fragmentation or low densities. Whatever the causes of their specialization, one might expect micro-habitat selection to be strong within the boundaries of the chosen niche to compensate for the costs linked to habitat constraints (variability of reproductive success due to high larval mortality, habitat fragmentation). We tested this hypothesis by investigating breeding site selection in the yellow-bellied toad (Bombina variegata) in the context of rock pools at riverbanks, which are supposed to be one of the pristine habitats of the species. In this species, breeding habitat use differs markedly from that of other European anurans since spawning takes place in small pools located in the close vicinity of rivers. Such pools experience high risks of drying up and flooding. By measuring 8 habitat variables at 187 rock pools along a 250 m river segment, we show a breeding habitat use based on a preference for pools with large volumes of water provided that they are devoid of alluvia, with a good exposition to sun. By ensuring longer water periods and faster development rates, large volumes and warm water probably reduce the mortality risks due to drying up (within suitable temperature range). This result contributes to understanding the process of niche conservatism (persistence of narrow range on certain dimensions of the niche), which is an important challenge in ecology and conservation biology.

Breeding site selection by colonial waterbirds given various combinations of constructed or natural alternatives over a 10-year period

Understanding breeding site preferences is important for management of colonial waterbirds. The number of active colonial waterbird nests at a series of four small constructed wetlands in Cape Town was counted monthly from 1999 to 2008. In total 491 pairs belonging to 11 waterbird species were involved. Between 1997 and 2004 a number of different artificial structures were used to attract colonial waterbirds to breed at one of the constructed wetlands. The changes in use of the different artificial structures, and of natural reedbeds, for nesting revealed the site preferences of different waterbird species. Structures that simulated flooded dead trees were most successful in attracting breeding waterbirds. Reedbeds were used for nesting when the number of such artificial structures was reduced. When the reedbeds were removed some birds returned to the artificial structures, whereas others moved to a more distant wetland. Some species were pioneers that provided public information about safety from predation that apparently encouraged birds in other species to settle. Safety from potential mammalian predators was clearly the prime consideration in breeding locality selection. Adverse winds and human disturbance were less important factors.

Differential response to abiotic conditions and predation risk rather than competition avoidance determine breeding site selection by anurans

Co‐existence of species has been a central debate in ecology for decades but the mechanisms that allow co‐existence are still heatedly disputed. The main paradigms have shifted among the importance of competition, predation and abiotic conditions as determinants of community structure. Differential habitat selection is considered to reduce competition and hence allow co‐existence. Our goal was to test hypotheses regarding how breeding site use of a population that was patchily distributed on a dynamic floodplain may facilitate coexistence: 1) do species co‐occur randomly or do they occur more or less often than expected by chance? 2) Do species use the same habitat types in equal proportions or do they use them differentially? 3) If they use habitat types differentially, is this differential use related to abiotic and biotic conditions? 4) Does interspecific competition predict breeding site use or do abiotic conditions and predation risk better predict habitat use? We collected presence/absence (i.e. detection/nondetection) data of egg clutches and larvae of four pond‐breeding anuran species during a two year study at a total of 353 ponds. We used site occupancy models and model averaging techniques to predict breeding site selection in relation to habitat types, abiotic and biotic factors. These parameters were corrected for imperfect detection of species. The rates of co‐occurrence were consistently higher than expected by chance. Species differed in the use of the main habitat types. Habitat types that were used by multiple species were used in a species‐specific manner in relation to both abiotic conditions and predation risk. Species preferred ponds where other species and fish were present. Although niche differentiation in breeding site selection is evident, our results do not support the pervasive role of competition avoidance in governing current breeding site selection. We conclude that differential habitat use and differences in response to abiotic conditions and predation risk can override competitive interactions, thereby facilitating local co‐existence and high species diversity.

Selection of den sites by wolves in boreal forests in Finland

Very little is known about den site selection by wolves in European boreal forests. We examined the selection of den sites by wolves in central-eastern Finland, where the wolf population has markedly increased over the last 10 years. We found 26 dens belonging to 12 packs where at least one wolf had been collared as part of a long-term ecological study of the wolves in the study area. Generalized linear mixed effect models (lmer) were constructed to explain the location of den sites in terms of their distance from human-modified areas such as built-up areas, roads and agricultural land. Natural factors such as forest type, ground vegetation and the presence of a water source were also considered. Our results highlighted the significance of human-modified areas in breeding site selection by boreal wolves in boreal forests. The results also indicated that hiding cover and sight distance are highly important factors for den site selection, whereas the forest type was of negligible importance.

Are There Optimal Densities for Prairie Birds?

Abstract. The major forces of food and predation shape fitness-enhancing decisions of birds at all stages of their life cycles. During the breeding season, birds can minimize nest loss due to predation by selecting sites with a lower probability of predation. To understand the environmental and social aspects and consequences of breedingsite selection in prairie birds, we explored variation in nest-survival patterns of the Lark Bunting (Calamospiza melanocorys) in the shortgrass prairie region of North America. Over four breeding seasons, we documented the survival of 405 nests, conducted 60 surveys to estimate bird densities, and measured several vegetative features to describe habitat structure in 24 randomly selected study plots. Nest survival varied with the buntings' density as described by a quadratic polynomial, increasing with density below 1.5 birds ha-1 and decreasing with density between 1.5 and 3 birds ha-1, suggesting that an optimal range of densities favors reproductive success of the Lark ...

Breeding-site selection by the poison frog Ranitomeya biolat in Amazonian bamboo forests: an experimental approach

Habitat selection in amphibians has typically been investigated using species that breed in medium-sized to large bodies of water. So far, few studies have focused on tropical, phytotelm-breeding species. We examined habitat selection in the context of reproductive resource use by Ranitomeya biolat (Morales, 1992), a poison frog that uses bamboo internodes as breeding sites. We conducted field observations and experiments using bamboo and PVC sections to test the effect of physical and biotic factors on tadpole deposition. Our field observations indicated that water volume, as well as internode length, height, and angle, may be important for tadpole deposition. We predicted that adult R. biolat would deposit tadpoles in pools that are close to the ground, pools with high water volume, pools contained in long structures, and pools without conspecific tadpoles or heterospecific predators. Our experiments demonstrated that water volume and the length of the structure containing the pool affect the pattern of tadpole deposition. Tadpoles were also deposited more frequently in experimental pools containing no other tadpoles or no predators. Our results support the prediction that phytotelm-breeding species, to maximize their reproductive success, should deposit their tadpoles in pools with water volumes that maximize nutrient content and that present no competitors or predators.