Matching the Multiple Scales of Conservation with the Multiple Scales of Climate Change

Abstract:  To anticipate the rapidly changing world resulting from global climate change, the projections of climate models must be incorporated into conservation. This requires that the scales of conservation be aligned with the scales of climate-change projections. We considered how conservation has incorporated spatial scale into protecting biodiversity, how the projections of climate-change models vary with scale, and how the two do or do not align. Conservation planners use information about past and current ecological conditions at multiple scales to identify conservation targets and threats and guide conservation actions. Projections of climate change are also made at multiple scales, from global and regional circulation models to projections downscaled to local scales. These downscaled projections carry with them the uncertainties associated with the broad-scale models from which they are derived; thus, their high resolution may be more apparent than real. Conservation at regional or global scales is about establishing priorities and influencing policy. At these scales, the coarseness and uncertainties of global and regional climate models may be less important than what they reveal about possible futures. At the ecoregional scale, the uncertainties associated with downscaling climate models become more critical because the distributions of conservation targets on which plans are founded may shift under future climates. At a local scale, variations in topography and land cover influence local climate, often overriding the projections of broad-scale climate models and increasing uncertainty. Despite the uncertainties, ecologists and conservationists must work with climate-change modelers to focus on the most likely projections. The future will be different from the past and full of surprises; judicious use of model projections at appropriate scales may help us prepare.     

Using virtual environments to improve the realism of choice experiments: A case study about coastal erosion management

Choice experiment surveys are commonly used to assess the general public׳s willingness to pay for different levels of environmental quality. However, respondents need to understand what they are valuing or they will make potentially wrong assumptions based on different experiences and frames of reference. Three-dimensional computer generated models or Virtual Environments (VE) have so far seen little use in economics research, probably due to the complexity and cost of developing and delivering them to study participants. The few studies that have used them find that VE are superior to static image presentations in helping people evaluate complex data. For this study we developed virtual environments for a choice experiment about coastal erosion management using free, easy-to-use software and Google Earth© satellite imagery and presented these to respondents as video tours. Our results indicate that the VE treatment reduced choice error, reduced left-right bias and improved respondent engagement and retention when compared with static images. There were also differences in WTP between the two groups.     

Distinguishing between Lévy walks and strong alternative models

Lévy walks are a widely used but contentious model of animal movement patterns. They are contentious because they have been wrongly ascribed to some animal species through use of incorrect statistical methods and because they have not been adequately compared against strong alternative models, such as composite correlated random walks. This lack of comparison has been partly because the strong alternative models do not have simple likelihood functions. Here I show that power-spectra and the distribution of the first significant digits (the leading non-zero digits) of the step lengths can distinguish between Lévy walks and composite correlated random walks. Using these diagnostic tools, I bolster previous claims that honey bees use a movement strategy that can be approximated by Lévy walks when searching for their hive or for a food source.     

On costs and decisions in population management

Many populations have a negative impact on their habitat, or upon other species in the environment, if their numbers become too large. For this reason they are often managed using some form of control. The objective is to keep numbers at a sustainable level, while ensuring survival of the population. Here we present models that allow population management programs to be assessed. Two common control regimes will be considered: reduction and suppression. Under the suppression regime the population is maintained close to a particular threshold through near continuous control, while under the reduction regime, control begins once the population reaches a certain threshold and continues until it falls below a lower pre-defined level. We discuss how to best choose the control parameters, and we provide tools that allow population managers to select reduction levels and control rates. Additional tools will be provided to assess the effect of different control regimes, in terms of population persistence and cost. In particular we consider the effects of each regime on the probability of extinction and the expected time to extinction, and compare the control methods in terms of the expected total cost of each regime over the life of the population. The usefulness of our results will be illustrated with reference to the control of a koala population inhabiting Kangaroo Island, Australia.     

Local Population Dynamics in Metapopulation Models: Implications for Conservation

Abstract: Habitat fragmentation and the division of populations into spatially separated units have led to the increasing use of metapopulation models to characterize these populations. One prominent model that has served as a heuristic tool was introduced by Levins and is based on a collection of simplifying assumptions that exclude information on the dynamics and spatial distribution of local populations. Levins's and similar models predict the proportion of occupied habitat patches at equilibrium and the conditions needed to avoid total extinction. There are many obvious concerns about using such models, including how realistic alterations might change the predictions and whether occupancy has any relationship to population-level processes. Although many of the assumptions of these simple models are known to be unrealistic, we do not know how the assumptions affect model predictions. We simulated a metapopulation, and our results show that assumptions such as homogeneity of habitat patches, random migration among patches, equivalent extinction probabilities in all patches, and a large number of patches can lead to large overestimations of habitat occupancy. But when we explicitly modeled the underlying population dynamics within each patch, we found (1) that there was a strong correlation between proportion of occupied patches and total metapopulation size and (2) that the distribution of individuals among patches was relatively insensitive to model assumptions. Thus, our results show that although realistic modifications will change model predictions for occupancy, occupancy and population trends will be correlated. These correlations between occupancy and population size suggest that occupancy models may have some utility in conservation applications.     

Conservation Easements: Biodiversity Protection and Private Use

Abstract:  Conservation easements are one of the primary tools for conserving biodiversity on private land. Despite their increasing use, little quantitative data are available on what species and habitats conservation easements aim to protect, how much structural development they allow, or what types of land use they commonly permit. To address these knowledge gaps, we surveyed staff responsible for 119 conservation easements established by the largest nonprofit easement holder, The Nature Conservancy, between 1985 and 2004. Most easements (80%) aimed to provide core habitat to protect species or communities on-site, and nearly all were designed to reduce development. Conservation easements also allowed for a wide range of private uses, which may result in additional fragmentation and habitat disturbance. Some residential or commercial use, new structures, or subdivision of the property were permitted on 85% of sampled conservation easements. Over half (56%) allowed some additional buildings, of which 60% restricted structure size or building area. Working landscape easements with ranching, forestry, or farming made up nearly half (46%) of the easement properties sampled and were more likely than easements without these uses to be designated as buffers to enhance biodiversity in the surrounding area. Our results demonstrate the need for clear restrictions on building and subdivision in easements, research on the compatibility of private uses on easement land, and greater public understanding of the trade-offs implicit in the use of conservation easements for biodiversity conservation.     

Self-organization in collective honeybee foraging: emergence of symmetry breaking,cross inhibition and equal harvest-rate distribution

De Vries and Biesmeijer described in 1998 an individual-oriented model that simulates the collective foraging behaviour of a colony of honeybees. Here we report how this model has been expanded and show how, through self-organization, three colony-level phenomena can emerge: symmetry breaking, cross inhibition and the equal harvest-rate distribution. Symmetry breaking is the phenomenon that the numbers of foragers visiting two equally profitable food sources will diverge after some time. Cross inhibition is the phenomenon that, by increasing the profitability of one of two equal food sources, the number of foragers visiting the other source will decrease. In some circumstances, the bees foraging on two sources of different profitabilities will be distributed between these sources such that the two average energy harvest rates are equal. We will refer to this phenomenon as the equal harvest-rate distribution. For each of these three phenomena, we show what the necessary behavioural rules to be followed by the individual forager bees are, and what the necessary circumstances are (that is, what values the model parameters should take) in order for these phenomena to arise. It seems that patch size and forager group size largely determine when each of these phenomena will arise. Experimenting with two types of currency, net gain rate and net gain efficiency, revealed that only gain rate may result in an equal harvest-rate distribution of foragers visiting different food sources.     

Optimal annual routines: new tools for conservation biology?

Many applied problems in ecology and conservation require prediction, and population models are important tools for that purpose. Formerly, the majority of predictive population models were based on matrix models. As the limitations of classical matrix models have become clearer, the use of individual-based models has increased. These models use behavioral rules imposed at the level of the individual to establish the emergent consequences of those rules at the population level. Individual behaviors in such models use an array of different rule types, from empirically derived probabilities to long-term fitness considerations. There has been surprisingly little discussion of the strengths and weaknesses of these different rule types. Here, we consider different strategies for modeling individual behaviors, together with some problems associated with individual-based models. We propose a novel approach based on modeling optimal annual routines. Annual routines allow individual behaviors to be predicted over a whole annual cycle within the context of long-term fitness considerations. Temporal trade-offs between different behaviors are automatically included in annual routine models, overcoming some of the primary limitations of other individual-based models. Furthermore, as well as population predictions, individual behaviors and indices of condition are emergent features of annual routine models. We show that these can be more sensitive to environmental change than population size, offering alternative, repeatable metrics for monitoring population status. Annual routine models provide no panacea for the problems of data limitations in predictive population modeling. However, as a result of their ability to deal with life-history trade-offs, as well as their potential for relatively rapid and accurate validation and parameterization, we suggest that annual routine models have strong potential for predictive population modeling in applied conservation settings.     

Traditional Plant Harvesting in Contemporary Fragmented and Urban Landscapes

Abstract: Ecosystem fragmentation and destruction can lead to restrictive administration policies on traditional harvesting by indigenous peoples from remaining ecosystem tracts. In New Zealand, concerns about endangered species and governmental policies that focus on species and ecosystem preservation have resulted in severely curtailed traditional harvesting rights. Although provision has been made for limited gathering of traditional plants from government‐administered conservation lands, it is unclear how much harvesting is undertaken on these lands and elsewhere and what this harvest might consist of. We interviewed seven expert Maori elders from the Waikato, New Zealand, to identify plant species they currently harvested and from where. We compared these data with the data we collected on permits issued for plant collecting on conservation lands in the same region. We sought to gain information on indigenous plant harvesting to determine the extent of permitted harvesting from conservation lands in the Waikato and to identify issues that might affect plant harvesting and management. Elders identified 58 species they harvest regularly or consider culturally important; over 50% of these species are harvested for medicinal use. Permit data from 1996 to 2006 indicated no apparent relationship between species of reported cultural significance and the number of permits issued for each of these species. Currently, few plant species are harvested from conservation lands, although some unofficial harvesting occurs. Elders instead reported that medicinal plants are frequently collected from urban and other public areas. They reported that plant species used for dyeing, carving, and weaving are difficult to access. Elders also discussed concerns such as spraying of roadsides, which resulted in the death of medicinal species, and use of commercial hybrids in urban planning. Local government may have an increasingly important role in supporting native traditions through urban planning, which takes account of cultural harvesting needs while potentially reducing future harvesting pressure on conservation lands. We suggest that active participation by the Māori community in the development and management of urban harvesting resources will result in positive outcomes.     

Family-related differences in social foraging tactic use in the zebra finch (Taeniopygia guttata)

When animals forage in groups, they can search for food themselves (producer tactic), or they can search for opportunities to exploit the food discoveries of others (scrounger tactic). Both theoretical and empirical work have shown that group-level use of these alternative tactics is influenced by environmental conditions including group size and food distribution, and individual tactic use can be influenced by several measures of individual state, including body condition. Because body condition has been shown to be heritable for various species, social foraging tactics may also be heritable. We looked for evidence of heritability in social foraging tactic use in the zebra finch (Taeniopygia guttata) by testing whether: (1) natural variation in body condition correlates with tactic use, (2) there are family-related differences in body condition, and (3) there are family-related differences in observed tactic use. Tactic use in the zebra finch was significantly related to body condition; individuals with lower body condition scores had a significantly higher use of the scrounger tactic as predicted from variance-sensitive producer–scrounger models. Body-condition scores differed significantly between families, suggesting that this aspect of individual state may have a heritable component. Finally, we recorded significant family-related differences in the use of producer and scrounger alternatives. These results are consistent with heritability in observed tactic use resulting from an inheritance of individual state, in this case body condition, which itself influences tactic use. Understanding how and why individuals differ in their use of alternative tactics is fundamental as it may provide important insights into inter-individual variation in fitness.     

A critical review of the precautionary approach of the IUCN impact classification for non-native taxa

The International Union for the Conservation of Nature (IUCN) proposes the use of the Environmental Impact Classification for Alien Taxa to standardize the classification of introduced species (IS) based on their environmental impact. The IUCN invoked the precautionary principle (PP) via 2 rules: the impact assigned to a taxon must be the maximum recorded impact across different impact assessments, and when the main driver of environmental damage is unclear, it must be assumed to be caused by the IS. The validity of PP is conditioned on the degree of emergency that warrants urgent decisions and on the scientific evidence demonstrating the advantages of applying a preventive measure. The application of an impact classification system does not arise in the context of an emergency that requires management; it occurs before the decision-making phase. Thus, PP should not be used in early steps of the risk analysis process. The IUCN also did not provide enough scientific basis to justify the use of PP. Instead, the PP rules appear to be rooted primarily in the ethical value system underlying conservation science. Conservationists assign intrinsic value to native species by virtue of their roles and relationships within ecological and evolutionary systems and processes; thus, individuals introduced in new environments not only cease to have value because they are no longer part of that natural diversity and lack those links with the rest of the ecosystem, but they become a threat to what conservationists value most. The consequence of this belief is that all introduced taxa will have an impact at some level, suggesting that values justify the PP rules.     

Justice in sustainability indicators and indexes

At least since the Brundtland Report, technical assessments of what can be sustained and values about what is desirable to sustain, for whom, and for how long have been intertwined. This intersection is particularly evident in the assumption that justice among people living today and between present and future generations is a key part of sustainability. In official international policy documents and academic studies of sustainability, this justice may include the equitable distribution of environmental benefits and burdens, distributive justice, or the ability of people to meaningfully contribute to decisions that affect their lives, participatory justice. Yet, the process of developing indicators and indexes to track movement toward or away from sustainability has been dominated by technical, economic, and environmental assessments. This raises questions about whether or not indexes align with and thus will monitor and encourage progress toward sustainability in a technically possible and desirable way. To begin to answer this question, this paper identifies definitions of justice used in sustainability discourse and evaluates the degree to which sustainability indicators and indexes align with these concepts. The 2010 Environmental Performance Index, Eurostat's Sustainable Development Indicators, and a group of local indicators and indexes are examined. It is found that the indicators embody various aspects of justice, though they are still significantly limited by the available data, especially as they generally cannot monitor inequities between subpopulations and have a limited capacity to monitor progress toward participatory justice.     

Hermaphrodite sex role preferences: the role of partner body size, mating history and female fitness in the sea slug Chelidonura sandrana

Costs and benefits associated with matings and the effects of mating frequency on fitness commonly differ between the sexes. As a result, outcrossing simultaneous hermaphrodites may prefer to copulate in the more rewarding sex role, generating conflicts over sperm donation and sperm receipt between mates. Because recent sex role preference models remain controversial, we contrast here some of their assumptions and predictions in the sea slug Chelidonura sandrana. For this hermaphrodite with sperm storage and internal fertilisation, risk-averse models assume that fitness pay-offs are constantly higher in the female than in the male function in any single mating. Moreover, excluding mutual partner assessment, these models predict male mating behaviour to be independent of receiver traits. The competing gender ratio hypothesis assumes that relative fitness pay-offs, and thus the preferred mating roles, vary and may reverse between matings and predicts that ejaculation strategies co-vary with receiver quality. We found that field mating rates of C. sandrana substantially exceeded what is required to maintain female fertility and fecundity, indicating large variation in direct female benefits between matings. We further demonstrate that male copulation duration adaptively increased with partner body size (i.e. fecundity) but decreased with recent partner promiscuity. These findings are compatible with the gender ratio hypothesis but contradict risk-averse models.     

Arzneimittel in der Umwelt: Umweltschutz im Arzneimittelrecht

The purpose of medicinal products is to act effectively on living organisms. If they reach environmental compartments it should be taken into account that they may have effects on biota in these compartments. Legislation on medicinal products has given little consideration to the risk that medicinal products may pose to the environment. In the near future there will be some progress according to amendments to the relevant legislative provisions.     

Ideal free distributions under predation risk

 We examine the trade-off between gathering food and avoiding predation in the context of patch use by a group of animals. Often a forager will have to choose between feeding sites that differ in both energetic gain rate and predation risk. The ideal site will have a high gain rate and low risk of predation. However, intake rate will often decrease when the patch is shared with other foragers and it may be optimal for some individuals to feed elsewhere. Within the framework of ideal free theory, we investigate the distribution of foragers that will equalise individual fitness gains. We focus on a two-patch environment with continuous inputs of food. With reference to existing experimental studies, we examine the effects of risk dilution, food input rates and an animal’s expectations of the future. We identify the effect of total animal numbers when one patch is subject to predation risk and the other is safe. Conditions under which the difference in intake rate in the two patches is constant are identified, as are conditions in which the ratio of animals in the two patches is constant. If current conditions do not alter future expectations an increase in input rates to the patches promotes increased use of the risky patch. Yet, if conditions are assumed to persist indefinitely the opposite effect is seen. When both patches are subject to predation risk, dilution of risk favours more extreme distributions, and may lead to more than one stable distribution. The results of these models are used to critically analyse previous work on the energetic equivalence of risk. This paper is intended to help guide the development of new experimental studies into the energy-risk trade-off. Received: 10 February 1995/Accepted after revision: 1 October 1995     

Bat Use of Remnant Old-Growth Redwood Stands

Most of the old-growth redwood ( Sequoia sempervirens ) in California has been cut; regenerating forests will probably never resemble those that were harvested, and what old growth remains on private land occurs in small, isolated remnant patches. The landscapes in which these stands occur differ so markedly from their original condition that their value as habitat to many species of wildlife, including bats, is unknown. Previous research in unfragmented redwood forests demonstrated that bats use basal hollows in old-growth redwoods as roosts. We sought to determine whether bats use similar old-growth trees as roosts when they occur in small, remnant patches of isolated old growth on commercial forest land. We compared bat occurrence in remnant and contiguous stands by collecting guano in traps suspended in hollows and by monitoring flight activity with ultrasonic bat detectors. Hollows in trees within the remnant stands had significantly more guano deposited per tree than the trees within the contiguous forest. The mean numbers of bat passes per night were statistically indistinguishable between the two treatments, although mean flight activity in the remnant stands was greater than in the contiguous forest. Bats frequently used basal hollows in small (<5 ha) stands of remnant old growth, which may be due to the closer proximity of remnants to stream courses, to their greater interface with edge where foraging success may be greater, or to the fact that the lower density of hollow-bearing trees in remnants than in contiguous forest favored greater use per tree. Significant use of small, residual old-growth redwood provides reason to maintain these remnants in managed landscapes as potentially important habitat for forest bats.     

Training Captive-Bred or Translocated Animals to Avoid Predators

Abstract: Animal reintroductions and translocations are potentially important interventions to save species from extinction, but most are unsuccessful. Mortality due to predation is a principal cause of failure. Animals that have been isolated from predators, either throughout their lifetime or over evolutionary time, may no longer express appropriate antipredator behavior. For this reason, conservation biologists are beginning to include antipredator training in pre-release preparation procedures. We describe the evolutionary and ontogenetic circumstances under which antipredator behavior may degenerate or be lost, and we use principles from learning theory to predict which elements can be enhanced or recovered by training. The empirical literature demonstrates that training can improve antipredator skills, but the effectiveness of such interventions is influenced by a number of constraints. We predict that it will be easier to teach animals to cope with predators if they have experienced ontogenetic isolation than if they have undergone evolutionary isolation. Similarly, animals should learn more easily if they have been evolutionarily isolated from some rather than all predators. Training to a novel predator may be more successful if a species has effective responses to similar predators. In contrast, it may be difficult to teach proper avoidance behavior, or to introduce specialized predator-specific responses, if appropriate motor patterns are not already present. We conclude that pre-release training has the potential to enhance the expression of preexisting antipredator behavior. Potential training techniques involve classical conditioning procedures in which animals learn that model predators are predictors of aversive events. However, wildlife managers should be aware that problems, such as the emergence of inappropriate responses, may arise during such training.     

On the use of the advanced very high resolution radiometer for development of prognostic land surface phenology models

Regulation of interannual phenological variability is an important component of climate and ecological models. Prior phenological efforts using the advanced very high resolution radiometer (AVHRR) as a proxy of vegetation dynamics have often simulated spring events only or failed to simulate interannual variability. Our aim is to address these shortcomings and to use the AVHRR to develop prognostic models for interannual land surface phenology and, critically, to test whether or not the developed models are superior to use of climatological phenology values from the AVHRR. Using datasets for the conterminous United States, we first filtered data to select regions and plant functional types for which the best-possible remotely sensed signal could be obtained. We then used a generalized linear model approach to model the relationship between an integrative productivity index and estimates of the start of season (SOS) and end of season (EOS) derived from the AVHRR, yielding models capable of prognostically predicting SOS/EOS events independently of satellite data. Mean absolute errors between the model-predicted and AVHRR-observed SOS/EOS ranged from 5.1 to 20.3 days. SOS errors were uniformly lower than EOS errors. SOS models for the deciduous broadleaf forest and grassland plant functional types produced lower errors than use of the climatological SOS values while all other models produced errors higher than those obtained from the climatological dates. Based on this criterion for success, we suggest that the AVHRR may not be appropriate for further development of prognostic land surface phenology models. However, an intercomparison of phenological dates from an independent spring index model, our model predictions, and the AVHRR observations indicated that interannual predictions from our models may be superior to the satellite data upon which they are based, implying that a further comparison between models based on the AVHRR and newer, superior sensors, should be conducted.     

Space use in territorial amberwing dragonflies: are residents female maximizers or neighbor minimizers?

Residents of mating territories interact with different categories of conspecifics: females, nonneighbor males, and neighbor males. Interaction with these different types of conspecifics is likely to have different costs and benefits; for example, interactions with females will be beneficial, while interactions with neighbors are more likely to be costly. In this study, we investigated patterns of intrusions and space use in territorial male amberwing dragonflies (Perithemis tenera) to test the idea that residents will adjust their use of space to maximize their beneficial interactions with conspecifics while minimizing their costly interactions with conspecifics. Because territories were arranged linearly around the edge of a pond, each resident had two neighbors, one of which was often closer to the focal resident than the other. Residents experienced more intrusions by neighbors and fewer intrusions by females on the side of their closer neighbor. Residents generally perched on the side of their territory that experienced the fewest intrusions by neighbors and the most intrusions by females, but the pattern was more strongly related to neighbor intrusions than female intrusions. Subsequent to pursuits of neighbors and females, residents tended to shift their perches away from where they pursued neighbors but toward where they pursued females. Nonneighbor intrusions were not affected by neighbor proximity, nor did residents adjust their space use in response to nonneighbor intrusions. Our results suggest that residents do adjust their space use in response to intrusions by conspecifics, that their adjustment depends on the type of conspecific that intruded, and that residents may be using a simple decision rule such as "move away from male intrusions, move closer to female intrusions" to adjust their within-territory space use.Communicated by D. Gwynne     

Biodiversity Offsets and the Challenge of Achieving No Net Loss

Businesses, governments, and financial institutions are increasingly adopting a policy of no net loss of biodiversity for development activities. The goal of no net loss is intended to help relieve tension between conservation and development by enabling economic gains to be achieved without concomitant biodiversity losses. biodiversity offsets represent a necessary component of a much broader mitigation strategy for achieving no net loss following prior application of avoidance, minimization, and remediation measures. However, doubts have been raised about the appropriate use of biodiversity offsets. We examined what no net loss means as a desirable conservation outcome and reviewed the conditions that determine whether, and under what circumstances, biodiversity offsets can help achieve such a goal. We propose a conceptual framework to substitute the often ad hoc approaches evident in many biodiversity offset initiatives. The relevance of biodiversity offsets to no net loss rests on 2 fundamental premises. First, offsets are rarely adequate for achieving no net loss of biodiversity alone. Second, some development effects may be too difficult or risky, or even impossible, to offset. To help to deliver no net loss through biodiversity offsets, biodiversity gains must be comparable to losses, be in addition to conservation gains that may have occurred in absence of the offset, and be lasting and protected from risk of failure. Adherence to these conditions requires consideration of the wider landscape context of development and offset activities, timing of offset delivery, measurement of biodiversity, accounting procedures and rule sets used to calculate biodiversity losses and gains and guide offset design, and approaches to managing risk. Adoption of this framework will strengthen the potential for offsets to provide an ecologically defensible mechanism that can help reconcile conservation and development. Balances de Biodiversidad y el Reto de No Obtener Pérdida Neta