Ecological Neighborhood Research Articles

Spatial Ecological Processes and Local Factors Predict the Distribution and Abundance of Spawning by Steelhead (Oncorhynchus mykiss) across a Complex Riverscape

Processes that influence habitat selection in landscapes involve the interaction of habitat composition and configuration and are particularly important for species with complex life cycles. We assessed the relative influence of landscape spatial processes and local habitat characteristics on patterns in the distribution and abundance of spawning steelhead (Oncorhynchus mykiss), a threatened salmonid fish, across ∼15,000 stream km in the John Day River basin, Oregon, USA. We used hurdle regression and a multi-model information theoretic approach to identify the relative importance of covariates representing key aspects of the steelhead life cycle (e.g., site access, spawning habitat quality, juvenile survival) at two spatial scales: within 2-km long survey reaches (local sites) and ecological neighborhoods (5 km) surrounding the local sites. Based on Akaike’s Information Criterion, models that included covariates describing ecological neighborhoods provided the best description of the distribution and abundance of steelhead spawning given the data. Among these covariates, our representation of offspring survival (growing-season-degree-days, °C) had the strongest effect size (7x) relative to other predictors. Predictive performances of model-averaged composite and neighborhood-only models were better than a site-only model based on both occurrence (percentage of sites correctly classified = 0.80±0.03 SD, 0.78±0.02 vs. 0.62±0.05, respectively) and counts (root mean square error = 3.37, 3.93 vs. 5.57, respectively). The importance of both temperature and stream flow for steelhead spawning suggest this species may be highly sensitive to impacts of land and water uses, and to projected climate impacts in the region and that landscape context, complementation, and connectivity will drive how this species responds to future environments.

Movement of adult temperate reef fishes off the west coast of North America

Movement of reef fishes has important consequences for the demography, spatial structure, and connectivity of their populations and their conservation and management. I synthesized and analyzed the available data on the movement of adult temperate reef fishes along the west coast of North America to summarize our current knowledge and identify future research needs. For 80% of analyzed species, the 75th percentile movement distance was less than 1.5 km. Movement distances of examined species are characterized by positively skewed frequency distributions and discrete movement ranges rather than unbounded diffusive or directional movement. There is no relationship between species body size and movement distance, but shallower living species move much shorter distances than deeper dwelling reef fishes. Such limited movement suggests that ecological neighborhoods of adult individuals are small, and finite movement ranges will have important consequences for understanding and modeling population connectivity in ecological and management contexts. Future research should focus on effects of habitat heterogeneity and population parameters on movement to investigate variability in movement patterns and its consequences for species’ ecology and management.

Bairro de Anhumas - Uma hipótese de bairro ecológico dentro da APA Corumbataí, perímetro Botucatu

The present study approaches the challenges for the strategy of the construction of an ecological neighborhood. Presents sustainable concepts showing the necessity of changes in the manner to produce, consume and interact with nature and the possibility of practices to deal with these changes. In an era of regional and global integration, local situations are affected by the dynamics in which they are inserted and the territorial management requires innovation and knowledge analysis. The article has the mission to question the sustainable land use of a neighborhood, within the environmental protection area, APA Corumbataí, Botucatu e Tejupá in the perimeter of Botucatu city, analyzing its different scales of influence and the hypothesis of the development of anecological neighborhood.

How ecological neighbourhoods influence the structure of the scavenger guild in low arctic tundra

AbstractAim How the ecological neighbourhoods of coast and forest affect arctic tundra ecosystems is a pressing question as the circumpolar tundra belt is shrinking under global warming. Mobile facultative scavengers are likely to negatively impact tundra biodiversity as dominant competitors or predators, if they spill over into tundra. Here, we provide the first quantitative assessments of the structure of a scavenger guild in low arctic tundra with emphasis on how it changes along spatial gradients from neighbouring ecosystems (i.e. forest and coast) and with altitude (i.e. productivity gradients). We also assess the likelihood of interactions between guild members that may negatively impact vulnerable tundra species.Location North‐eastern part of Norway.Methods Extensive records of scavenger prevalence were obtained by deploying automatic digital cameras at experimental carcasses in tundra regions covering several thousand square kilometres and three winters in northern Norway.Main conclusions We found short‐range neighbourhood effects of forest and coast within the tundra scavenger guild. Species richness declined steeply with decreasing distance from the neighbouring ecosystems, in particular subarctic forest, and with increasing altitude. Bird species with strongholds in forest (golden eagle Aquila chrysaetos and hooded crow Corvus cornix) or along the coast (white‐tailed eagle Haliaeetus albicilla) were mostly responsible for short‐range neighbourhood effects on guild structure. However, the two most abundant guild members, the common raven Corvus corax and the red fox Vulpes vulpes, exhibited no spatial patterns within the range of neighbourhoods and altitudes examined. There was a clear diurnal segregation in the use of carcasses between birds and mammals reducing the likelihood of direct interactions between these two taxa. Presence of red fox appeared to exclude the arctic fox Vulpes lagopus, the only endemic tundra species within the guild, from carcasses.

A closer look at the spatial architecture of aphid clones

Nearly 25 years ago, Ellstrand & Roose (1987) reviewed what was known at the time of the genetic structure of clonal plant species. What is the relationship between space and clonal fitness, they asked. What is the best way for a clone to grow within its ecological neighbourhood? The pot had been stirred 10 years previously by Janzen (1977), who pointed out how little we know about the population biology of clonal organisms like dandelions and aphids. He wondered whether, like good curries, outward appearances masked common ingredients. Because in no small part of the advent of molecular ecology, we know more about clonal life histories today, particularly in plants (van Dijk 2003; Vallejo-Marin et al. 2010). Surprisingly, studies of the spatial architecture of aphid clones have been comparably rare. In this issue of Molecular Ecology, Vantaux et al. characterize the finescale distribution of the black bean aphid (Aphis fabae) and in so doing, help to fill that gap. They describe a moderate degree of intermingling between aphid clones over a growing season--A. fabae clones are ‘sticky’, but only a bit. By mixing, clones directly compete with each other as well. The results of Vantaux et al. (2011) will help to integrate evolutionary patterns in aphids with the appropriate ecological scales out of which those patterns emerge.

Dossier « Adaptation aux changements climatiques » - Vers une transition énergétique ?

L’energie n’est souvent percue que dans sa dimension technique. Les energies renouvelables sont ainsi frequemment apprehendees comme de simples substituts aux energies fossiles qu’elles sont censees remplacer dans le systeme technique et social actuel. Leur capacite a satisfaire cet objectif est d’ailleurs, souvent a juste titre, mis en doute. Les energies renouvelables exigent en effet des systemes techniques, politiques, economiques et sociaux radicalement differents de ceux dans lesquels evoluent les energies fossiles et nucleaire. Elles n’ont de sens et d’avenir que dans un cadre institutionnel nouveau, conduisant notamment a une reappropriation de la question energetique par les citoyens et a une decentralisation de son exploitation. C’est d’ailleurs la que reside leur principal enjeu pour notre societe. Car, en tissant un nouveau rapport au monde et a la nature, elles ouvrent notre univers des possibles au-dela de la seule innovation technologique.

Analysis of feral pig (Sus scrofa) movement in a Hawaiian forest ecosystem using GPS satellite collars

AbstractThe ecosystem altering impacts of feral pigs have been widely documented around the world. However, a general framework for their control and management has been lacking, especially in island ecosystems. One reason for this lack of management is that we have little knowledge of how pigs move through different island ecosystems, especially ones that are topographically challenging such as Hawai‛i. With recent advances in telemetry and movement modeling, it is now becoming practical to understand where these large introduced animals are moving and how they are using habitat. Hence, the primary goal of this study is to understand feral pig movement in terms of terrain, slope restrictions, and distance traveled beyond a natal site, within an island forested landscape. Based upon this goal, the objectives were to (1) assess different methods of time-series analysis in terms of animal movement and home range, and (2) use the information to inform wildlife management and policy. In 2008, a total of 36 feral pigs were collared with Global Positioning System (GPS) units across four different field sites on three Hawaiian Islands (Maui, Molokai, and Kauai) and tracked for an average of 60 +/- 10 days. Of the 36 collared animals, only four could be used for analysis due to various technological failures. Using three different movement modeling approaches (Brownian Bridge, minimum convex polygon, and the kernel density estimator), we found that feral pigs, within the heterogeneous landscape of Hawaiian watersheds have a spatial recognition limit or ecological neighborhood of between 1.65 and 2 km. All three methods indicated a slight variation of individual home range estimates. These results demonstrated that pigs move less in heterogeneous and heavily vegetated ecosystems. Even under the most conservative estimate, pigs moved 0.2 km/day. Considering that feral pigs disperse exotic plants and increase nutrient loading of streams, our results indicate that even a small abundance of pigs have a very large impact on the native ecosystems of Hawaii, due to their concentration around a natal site or resource center. Based upon this work, we suggest that managers must increase measures to limit habitat connectivity, such as perimeter fences and trapping along remote roadways that are used as feral pig dispersal mechanisms.

Contemporary pollen flow, characterization of the maternal ecological neighbourhood and mating patterns in wild cherry (Prunus avium L.)

Conversion of lowland woodland to agricultural land and resulting fragmentation in Britain has been ongoing since Neolithic times. To counteract this decline, plantations of native species, often based on non-British planting stock, have been established. This may ultimately be detrimental to the integrity of the native gene pool. We explore the genetic and ecological factors influencing the success of components of the local pollen pool, including the effect of a non-native planting on an ancient woodland population of wild cherry. Wild cherry exhibits gametophytic self-incompatibility (GSI) and vegetative reproduction, both of which may be determinants of paternal success. The majority (61%) of the successful pollen originated from within the study site with a maximum pollen transfer distance of 694 m. There was a distinct departure from random mating, with over half the successful pollen originating from trees which occur within 100 m of the mother tree. Self-incompatibility, clonality, tree size and proximity to the mother tree were all found to influence paternal success. Kinship of pollen gametes within a maternal progeny was highest when a mother tree was surrounded by a large number of ramets of a single, compatible clone consisting of large, adult trees. Although the contribution from the non-native plantation is currently low, it is likely that this will increasingly contribute to the progeny of the adjacent ancient population as it matures. The results clearly show that in self-incompatible species, such as P. avium, close neighbours may be pollinated by very different components of the local pollen pool.

TOWARDS A SUSTAINABLE NEIGHBORHOOD: THE ROLE OF OPEN SPACES

The neighborhood is a basic planning entity in modern residential planning theories. However open spaces as a vital constituent of the neighborhood’s physical structure, have an important role to play. They are the arena of both, neighbors’ outdoor interactions – consequently building the neighborhood’s sense of community - and the micro ecological sphere - setting its parameters and configuring its fundamentals. The paper aims to investigate the roles and responsibilities that open spaces -in neighborhoods- have to take to achieve sustainability goals and objectives. However it follows an approach based on both the social and ecological neighborhood’s ability to tackle sustainability issues. It focuses on the typical open space structure of the neighborhood as the media of different social and ecological interactions. Regarding this concern the paper differentiates between two main categories of the neighborhood’s open space; greenspace and Moreover, the paper develops a three dimension matrix that sets the interrelations between different types of neighborhood open space and sustainability goals and objectives that have to be achieved within the community. It uses this matrix to assess the sustainability performance of different typologies of open space; moreover it determines the priorities of sustainability parameters that have to be applied to an assigned open space. Finally, the paper applies its findings to two different typologies of open spaces in Lebanon; Beirut Pine ‘Horsh Beirut’ as a greenspace, and the historical market, and pedestrian streets in Byblos as a greyspace. The application comes to show the validity of conceptual application of the proposed matrix.

The effect of migration on the spatial structure of intraguild predation in metapopulations

We consider the effects of migration on intraguild predation (IGP) via lattice models and pair approximation. The following results can be found: there exists asymmetry between two consumers’ migration effects on the spatial structure of IGP; migration of each consumer reduces its own clumping degree; the spatial structure is influenced by the ecological neighborhood.

Mating system and pollen gene flow in Mediterranean maritime pine

Mating systems define the mode of gene transmission across generations, helping to determine the amount and distribution of genetic variation within and among populations of plant species. A hierarchical analysis of Mediterranean maritime pine mating system (61 mother trees from 24 plots, clustered in three populations) was used to identify factors affecting mating patterns and to fit pollen dispersal kernels. Levels of ovule and seed abortion, multi- and single-locus outcrossing rates and correlated paternity were estimated from progeny arrays and correlated with ecological stand variables and biometric tree measures. Pollen dispersal kernels were fitted using TwoGener and KinDist indirect methods and simulations were carried out to identify relevant factors affecting correlated paternity. Maritime pine showed high outcrossing rates (t(m) and t(s) approximately 0.96) and relatively low levels of correlated paternity [an r(p) of 0.018 (Ritland's estimate) or 0.048 (Hardy's estimate)], although higher than in other anemophilous tree species. Mating system parameters had high variation at the single-tree level (99-100%) but no stand or population effect was detected. At the single-tree level, outcrossing rates were correlated with tree (diameter and height) and crown size. In addition, correlated paternity showed a significant negative correlation with tree height, height to crown base and height to the largest crown width, probably reflecting the importance of the trees' 'ecological neighborhoods'. Indirectly estimated pollen dispersal kernels were very leptokurtic (exponential-power distributions with beta<<0.5), with mean dispersal distances from 78.4 to 174.4 m. Fitted dispersal kernels will be useful in building explicit simulation models that include dispersal functions, and which will contribute to current conservation and management programs for maritime pine. Nevertheless, the numerical simulations showed that restricted dispersal, male fertility and phenological overlap could only partially explain the observed levels of correlated paternity; so other factors may also be relevant for the management of this valuable forest tree species.

Mating patterns, pollen dispersal, and the ecological maternal neighbourhood in a Prunus mahaleb L. population

Gender polymorphism, plant-animal interactions, and environmental heterogeneity are the three important sources of variation in mating system and pollen dispersal patterns. We used progeny arrays and paternity analysis to assess the effects of gender type and density level on variation in mating patterns within a highly isolated population of Prunus mahaleb, a gynodioecious species. All the adult trees in the population were sampled and located. The direct estimate of long-distance insect-mediated pollination events was low (< 10%). Gender expression deeply influenced the mating system, decreasing the outcrossing rates (t(m)) and the pollen pool diversity in hermaphrodite trees. Long intermate distances (> 250 m) were significantly more frequent among female mother trees. Variation in local tree density also affected pollen pool diversity and intermate distance, with a higher effective number of fathers (k(e)) and longer intermate distances for female trees in low-density patches. A canonical correlation analysis showed significant correlations between mating variables and the maternal ecological neighbourhood. Only the first canonical variable was significant and explained 78% of variation. Outcrossing rates tended to decrease, and the relatedness among the fathers tended to increase, when mother trees grew in dense patches with high cover of other woody species and taller vegetation away from the pine forest edge. We highlight the relevance of considering maternal ecological neighbourhood effects on mating system and gene flow studies as maternal trees act simultaneously as receptors of pollen and as sources of the seeds to be dispersed.

A Patch Hath Smaller Patches: Delineating Ecological Neighborhoods for Parasites

Use of the host individual as a boundary for parasite populations and communities provides an unambiguous spatial unit that is useful for pattern description, but this framework precludes consideration of the host landscape and within-host population dynamics. Recognizing host individuals as spatially and temporally complex landscapes requires modified concepts of parasite populations and communities. An outline of the currently accepted hierarchies of parasite populations and communities is provided on the basis of ecological neighborhoods that are delineated by discrete habitat patches or functional dynamics (or both), as opposed to host individuals. This parasite-based framework accommodates consideration of both within- and among-host dynamics and facilitates investigation into the mechanisms by which these 2 levels of investigation interact.

Ecological play in the coevolutionary theatre: genetic and environmental determinants of attack by a specialist weevil on milkweed

1 We studied the genetic and environmental determinants of attack by the specialist stem-attacking weevil, Rhyssomatus lineaticollis on Asclepias syriaca. 2 In natural populations, the extent of stem damage and oviposition were positively correlated with stem width, but not stem height. We hypothesized that both genotypic and environmental factors influencing stem morphology would affect attack by weevils. 3 In a common garden study with 21 full-sib families of milkweed, both phenotypic and genetic correlations indicated that weevils impose more damage and lay more eggs on thicker stemmed plants. 4 Of three other putative resistance traits, only latex production showed a negative genetic correlation with weevil attack. 5 When neighbouring grasses were clipped to reduce light competition, focal milkweed plants received up to 2.6 times the photosynthetically active radiation and 1.6 times the red to far red ratio of light compared with plants with intact grass neighbours. Focal milkweed plants were therefore released from the classic neighbour avoidance response and had 20% shorter internode lengths, were 30% shorter, and had 90% thicker stems compared with controls. 6 Clipping of grass neighbours resulted in nearly 2.7 times the damage and oviposition by stem weevils, thus supporting the hypothesis of an environmental or trait-mediated indirect influence on resistance. 7 Although attack of plants by weevils strongly increases the probability of stem mortality, thicker stems experience lower mortality, thus counteracting the selective impact of weevil-induced plant mortality. 8 The determinants of attack on milkweeds include both genetic variation for stem thickness and an indirect environmental influence of plant neighbours. If milkweeds and weevils are coevolving, the interaction is diffuse because the ecological neighbourhood is likely to modify the patterns of reciprocal natural selection.

USE OF A SMOOTHER TO FORECAST OCCURRENCE OF EPIPHYTIC LICHENS UNDER ALTERNATIVE FOREST MANAGEMENT PLANS

We used habitat models to forecast the frequency of occurrence of epiphytic lichen species in a forested landscape under two alternative plans: a literal application of standard prescriptions in the Northwest Forest Plan and a plan patterned in part after natural disturbance regimes. The plans were evaluated for the Blue River watershed in the Cascade Range of Oregon, USA. We used two model types: logistic regression and an ecological neighborhood model using a form of nonparametric regression (SpOcc; Species Occurrence Modeler). Both logistic regression and SpOcc successfully estimated the occurrence of the lichen Lobaria oregana in the current landscape, based on elevation and structural classes of forests. Structural classes were defined by combinations of (1) overstory retention of remnant trees, (2) young cohort age, and (3) stream position (upland vs. riparian). Lobaria oregana rapidly diminished in frequency in the landscape at elevations above 900-1000 m. Young, even-aged stands had little or no Lobaria oregana. Most of the other structural classes, however, were very similar in frequency of Lobaria. The differences in lichens between retention levels and between mature and old growth stands were very small com- pared to the differences with respect to elevation and clearcutting. Similar results, with varying importances of elevation and forest structure, were obtained for most of the 20 species with the strongest models. Many of these species were associated with old growth, and many were forecasted to be more frequent under either management plan than in the current landscape. This is a likely response to the reduction of even-aged management in this landscape. We recommend using SpOcc for flexible nonparametric fitting of species relationships to a multivariate habitat. SpOcc avoids the need to specify response functions and, because it is multiplicative rather than additive, automatically models responses to interactions among predictors.

A Strategy for Describing and Monitoring Bat Habitat

Bats use more features in the landscape than a hibernaculum or maternity roost, but management plans often are made without more information than this because it is time-consuming and costly to collect. This leads to management based on oversimplified bat ecology with no way of incorporating those knowledge gaps. Ecological neighborhoods are the space used by a single organism or a group of organisms during a time period of interest. I used information about the behavior of pallid bats (Antrozous pallidus) to create an ecological neighborhood for a colony in central Nevada and compared it to a neighborhood created with empirical data collected from the same individuals. I also present a method for ranking the conservation value of neighborhoods that incorporates ecology and differences in data quality. I demonstrated how to use ecological neighborhoods to identify potential conflicts in natural resource management, quantify habitat loss, and monitor cumulative impacts.

The application of focal species knowledge to landscape design in agricultural lands using the ecological neighbourhood as a template

The focal species approach to nature conservation provides a method for identifying management actions required to meet the needs of the most vulnerable species in a landscape with respect to the threatening processes responsible for their decline. For each threat, a focal species is identified as the one with the most critical requirement pertaining to the threat. With multiple threats, the resulting suite of focal species can be regarded as a “focal community”, whose combined needs are used to address a range of management actions. In this paper, the critical requirements of a focal community of resident land birds are identified with respect to the threats arising from the loss, fragmentation and degradation of habitat in the central wheat-belt of Western Australia. This knowledge of their critical requirements is then used to guide a landscape design procedure for the enhancement of bird habitat in the Gabbi Quoi Quoi sub-catchment of Western Australia. The landscape design procedure is framed against the concept of the ecological neighbourhood, where the necessary size, spatial arrangement, area of influence and connectivity of existing landscape elements are used as a starting point for habitat restoration and re-vegetation.

Importance of the predator's ecological neighborhood in modeling predation on migrating prey

Most mathematical descriptions of predator‐prey interactions fail to take into account the spatio‐temporal structures of the populations, which can lead to errors or misinterpretations. For example, a compact pulse of prey migrating through a field of quasi‐stationary predators may not be well described by standard predator‐prey models, because the predators and prey are unlikely to be well mixed; that is, the prey may be exposed to only a fraction of the predator population at a time. This underscores the importance of properly accounting for the ecological neighborhood, or effective feeding range, of predators in models. We illustrate this situation with a series of models of salmon smolts migrating through a reservoir arrayed with predators. The reservoir is divided into a number of longitudinal compartments or spatial cells, the length of each cell representing the upstream‐downstream range over which predators can forage. In this series of models a 100‐km‐long reservoir is divided, successively into 2, 5, 10, 25, 50, 100, 200, and 400 cells, with respective cell lengths of 50, 20, 10, 4, 2, 1, 0.5, and 0.25 km. We used a detailed individual‐based simulation model at first, but to ensure robustness of results we supplemented this with a simple analytic model. Both models showed sharp differences in the predicted mortality to a compact pulse of smolt prey moving through the reservoir, depending on the number of spatial cells in the model. In particular, models with fewer than about 10 cells vastly overpredicted the amount of mortality due to predators with activity ranges of not more than a few kilometers. These results corroborate recent theoretical and simulation studies on the importance of spatial scale and behavior in modeling predator‐prey dynamics.

Ecological Neighborhoods in Red-Cockaded Woodpecker Populations

Ecological Neighborhoods in Red-Cockaded Woodpecker Populations

The effects of ecological and genetic neighbourhood size on the evolution of two competing species

Summary Individual-based simulations were conducted to examine the effect of a small ecological neighbourhood (art area in which ecological processes such as density-dependent factors operate) and the genetic neighbour-. hood size (the size of an area from which the parents may be assumed to be drawn at random) on the co-. evolution of two competing species. For the simulations, individuals of two consumer species compete for two types of food organisms. Different genotypes (one locus and two alleles) have different efficiencies of food acquisition for different food types. Individual consumer organisms search for food within their home ranges and reproduce depending on the amount of food eaten. The dispersal distance of the offspring follows a normal distribution with a zero mean and cr d standard deviation. Simulations were conducted by varying the home range size, mating area (area from where individuals choose their mates), standard deviation of dispersal distance, food generation time, the reproductive rates of food populations and the sizes and number of independent food populations. Food organisms reproduce either within one population or independently within 16 spatially divided populations. For all the simulations, competitive exclusion was the most frequent outcome and character displacement was the least frequent outcome. Through a 200-generation simulation, the two consumer species could co-exist longer and maintain a polymorphic resource use longer when the home range and mating size were small in 16 spatially divided populations than when random mating and homogeneous interaction occurred within a community (perfect mixing: population). For perfect mixing populations, the frequency of character displacement increased as the fbod generation time became short and the reproductive rates of food decreased. It follows from the results that: the sizes of the genetic and ecological neighbourhoods and the mode of resource dynamics can affect the evolution of two competing species.