Habitat: A Concept by Any Other Name Would (Not) Smell as Sweet (hosted by TWS)

Symposium
ROOM: RSCC, D7
SESSION NUMBER: 8269
 
n the realm of wildlife ecology, habitat is a word that encompasses our understanding of species’ natural history and long-term persistence. As our title modification of Shakespeare’s quote reflects – the concept of habitat is engrained in our profession. Nonetheless, our collective use and misuse of this term, and our quantification and mapping of habitat, have significant implications for conservation, restoration, and land management.  Despite almost 20 years of exhortations in the literature to carefully consider our use of the word, imprecise use and abuse continue: the term has become a panchreston.  Therefore, we propose a forum to explore both challenges and opportunities for our field, centered on the concept of habitat.  Each speaker will provide a case study, often focused on a challenge related to habitat, incorporating three tenets about how to overcome these challenges in their situation. The session will be divided into 4 themes: 1) terminology and setting the stage, 2) an example with spotted owls and how science was and is currently executed, 3) restoration challenges, and 4) opportunities and techniques to restore habitat to the lexicon of useful ecological terms including developing a recommendation for guidelines to journal editors. Our goal will be to provide a broad audience with both on-the-ground suggestions following our exploration of the use (or misuse) of the term habitat and guidance on how our profession, with our current tools and new understanding, can work together to improve our portrayal of wildlife habitat.

8:00AM Misuse of Habitat Terminology, Implications, and Potential Solutions
  Andrea Darracq, Jordan Tandy, Darren A. Miller, Paul Krausman
Habitat is the sum total of conditions required for a species to survive and reproduce. As such, the term habitat is species-specific and should not be used to generally describe vegetation conditions. Similarly, habitat-related terms, such as habitat use or selection, are also often used incorrectly. On a broad scale, current wildlife professionals must agree that correct use of habitat terminology is important for clear communication. We contend that misuse of habitat related terminology makes it difficult to communicate management needs and goals, develop and interpret research, inform decisions in policy and legal arenas, and compromises outreach efforts. Despite potential ramifications associated with incorrect use, use of habitat related terms still appears erroneously in wildlife biology and other fields. This includes widespread misuse in wildlife journals, classroom settings, and by wildlife-related organizations further perpetuating the misuse of habitat terminology. For example, in a recent survey of published material we discovered that during 1998-2017, 31% and 65% of the papers in the Journal of Wildlife Management used the term habitat incorrectly or fluctuated between correct and incorrect use, respectively. We also found that most university course descriptions were not accurate in their use of habitat terminology and conservation organizations, including The Wildlife Society, fluctuated between correct and incorrect usage of the term habitat. There are several ways to eliminate the misuse of habitat terminology including reinforcing correct usage within university programs, editing the websites of wildlife related organizations to ensure habitat terminology is used correctly, training of personnel within wildlife related organizations, including universities, to standardize use of habitat terminology when communicating, and ensuring misuse is fixed during the editorial process within journals. However, these suggestions will not be successful unless most wildlife professionals embrace, appreciate, and understand the need to use precise, consistent messages when discussing habitat or habitat-related issues.
8:20AM “Critical” Habitat: Legal Interpretations, Pitfalls, and Opportunities
  James Lynch
8:40AM Regulatory Definitions of ‘Habitat’ in Critical Habitat Designations Under the ESA: A Case Study with Northern Spotted Owl
  Bruce Hollen, Brian Woodbridge, Elizabeth Glenn, Jim Thrailkill, Bruce Marcot
Perhaps in no other context is the correct understanding and application of the term “habitat” more consequential than in designation and management of critical habitat under the Endangered Species Act. Critical habitat is not only intended to provide for the conservation (survival and recovery) of a listed species, but also places the substantive requirement under section 7 of the act to avoid the destruction or adverse modification of critical habitat for any action authorized, funded or carried out by a federal agency. We examine the regulatory language and compare it to the analytical approach used by the USFWS to designate revised Critical Habitat for northern spotted owls (Strix occidentalis caurina). Based on extensive literature review, input from expert panels, and analysis of environmental conditions at owl home ranges, the USFWS developed a hierarchical modeling procedure that incorporated vegetation composition and structure, spatial arrangement of patches and biophysical conditions (e.g. slope, elevation, climate) at scales relevant to site selection by northern spotted owls. To incorporate broad-scale variation in available conditions and spotted owl ecology, habitat models were developed individually for 11geographic ‘modeling regions. This process of synthesizing the spotted owl literature and incorporating it into a conservation planning approach provides a repeatable defensible approach to species recovery under the ESA.
9:00AM Changing Paradigms in Understanding Spotted Owl Habitat: Implications for Forest Management and Policy
  Alan Franklin, R Gutiérrez, Peter Carlson, Jeremy Rockweit
The northern spotted owl (Strix occidentalis caurina) has been a focal species in the United States in terms of loss and fragmentation of mature and old-growth conifer forests in the Pacific Northwest. Initial research found a strong range-wide association between spotted owls and mature and old-growth coniferous forests and these vegetation types were considered synonymous with spotted owl habitat. While this paradigm still holds in the northern part of its range, subsequent research in the southern portion of the owl’s range indicated that forest landscape heterogeneity was also an important determinant of habitat quality. While older forest remains an important component defining habitat quality for northern spotted owls, age of forest is not the sole component because structural features and modest levels of fragmentation of older forest appear to enhance or maintain habitat quality. Thus, redefining habitat in this portion of the owl’s range requires a reconsideration of what was previously considered habitat fragmentation. Under this new paradigm, landscape heterogeneity, previously thought of as habitat fragmentation, was considered an important component of northern spotted owl habitat. Better understanding of mechanistic explanations of habitat quality, such as prey abundance and natural disturbance regimes, partially explain this paradigm shift in defining habitat. The response of owls to habitat conditions provides an example of how habitat can vary across the geographic range of a species and that understanding habitat quality and its mechanistic explanations are important for understanding the role of habitat in sustaining populations over time.
9:20AM Assessing Influence of Movement, Diet, Energetics, and Forest Structure to Define Coastal Marten Habitat
  Katie Moriarty, Marie Martin, Patrick Tweedy, Charlotte Eriksson, Mark Linnell, Brent Barry, Jake Verschuyl, David Green, Taal Levi, Matthew Delheimer
Defining habitat can be challenging for well-studied species (e.g., northern spotted owl, ungulates, waterfowl), and the challenge is amplified for rare and little-known species. Montane populations of Pacific martens (Martes caurina) are generally associated with mature forests. Structural elements (e.g., large trees and snags, woody debris) provide opportunities for optimizing denning, resting, and foraging. In the last few years it has become apparent that small and isolated coastal populations of the Humboldt subspecies of Pacific martens (Martes caurina humboldtensis) occupy a greater diversity of vegetation types, including an Oregon population that occurs in a narrow strip of ~70 year-old forested stands, <1 km from the ocean. Recognizing that the concept of habitat is multidimensional, we gathered information on distribution, diet, occurrence of potential predators and prey, movement, energetics, resting, and denning locations. We compared fine-scale vegetation characteristics with remotely sensed multi-scale predictive habitat models for coastal marten populations. We explored the utility of vegetative structural variables versus species interaction variables in improving predicative habitat model performance. We concluded no single variable strongly influenced predicted occurrence, but biotic factors and seasonal information increased confidence in our predicted habitat models. Vegetation in coastal forests appears to provide, at least seasonally, prey and fruit, and overhead shrub cover. Predicted and realized energetic expenditures may ultimately serve as a basis for assessing predicted habitat, as tradeoffs likely explain marten distributions in unusual areas. For instance, we predict locations with high quantities of accessible prey but poor-quality rest locations may be similar energetically with areas with lower accessible prey, but less competition for resources and more thermally efficient resting locations. Consistently being able to identify areas with sufficient resources for energetic stability, escape cover from predators, and a diversity of resting and denning locations, will be a productive undertaking for future work.
09:40AM Break
10:10AM Linking Ungulate Habitat to Fitness – New Approaches with Large Data Sets
  Mary Rowland, John Cook, Rachel Cook, Ryan Nielson, Michael Wisdom
Studies of habitat selection and use by large herbivores are foundational for understanding their ecology and management, especially if predictors of use reflect habitat characteristics related to demography or fitness. The wildlife literature is replete with examples of habitat models for ungulates; however, linking habitat conditions to ungulate performance is challenging and rarely attempted. We initiated a study to better understand drivers of habitat use, how they interact to predict use, and current habitat conditions for elk (Cervus canadensis), a wide-ranging species across the western USA. We used a niche-based definition of habitat, i.e., that habitat encompasses the resources and conditions present in an area that produce occupancy, including survival and reproduction needed for persistence of an organism. This definition links habitat to the full suite of environmental requirements of a species. We developed and evaluated a regional habitat-use model for elk emphasizing mechanistic covariates that explicitly represent habitat requirements and relate to ecological processes of energy acquisition or loss, namely nutrition and human disturbance. Although many ungulate habitat models incorporate vegetation proxies for nutrition, we modeled dietary digestible energy measured from tame animals, a measure of nutrition directly linked to animal performance. We lacked regional data to include other potential habitat factors that can play an important role in affecting elk habitat use (e.g., predation and competition). Yet our models performed well, and we demonstrated a strong relation between elk nutritional resources and pregnancy rates and autumn body fat of lactating females. Future challenges in modeling nutrition and habitat use for herbivores include changing patterns of vegetation and thermal regimes under climate change. Our work demonstrated the feasibility of combining disparate data sets through meta-analysis to develop regional models linking habitat features to fitness, an approach that can inform management to improve elk nutrition, distributions, and performance.
10:30AM A Shifting Baseline for Time and Space: Predicted Habitat Differs Depending on the Your Scale
  Sam Cushman
Habitat relationships are scale dependent and the strength and nature of the association between organism occurrence, performance, movement and behavior are all dependent on the scale at which observations are made. In this talk I present several examples of scale dependence in habitat selection and movement of wildlife. I first show scale dependence in habitat relationships of American marten, European brown bear and clouded leopard. Then I illustrate how scale dependence is also critically important in studies of animal movement in relation to landscape features, with examples from African lion, and African elephant. Collectively these examples illustrate high importance of considering scale dependence in wildlife ecology research.
10:50AM Restoration on Conservation Lands – What’s the Problem?
  Kyle Spragens, Nicole Czarnomski, Tish Conway-Cranos, Jay Krienitz
Public lands often provide limited area to fulfill multiple objectives and mandates required of today’s agencies. Historically, acquisitions of public lands were justified using a single or perhaps a group of iconic or relatable-to-the-public species that would garner support. In some cases, the need to justify the acquisition masked the dilapidated characteristics of the available land and its past habitat type and function. Subsequent management actions may have transformed the parcel into a functional “habitat”, but based on a limited scope due to funding obligations. Facing a suite of new and intensifying pressures, past public land objectives are being challenged to fulfill a broader suite of ecosystem functions at a given location. We provide current examples in Washington State where pubic agencies are being challenged to balance multi-species benefits and public support through trade-offs of habitat value.
11:10AM Young Forest Initiative – Balancing forest regeneration in Forever Wild
  Shawn Cleveland, Ross Conover
The need for early seral stages in ecological systems, often coined early succession habitat, has garnered great interest in recent years throughout North America. In the western United States, some have described an early successional crisis in forested systems stemming from a decade of focusing on late-successional species. In mid-western and eastern forests, collaborative efforts such as The Young Forest Initiative aim to improve and provide early seral stages for young forest dependent species. A central goal of this effort states: “to keep the land healthy, we need a balance of different habitats.” Not only is the concept of habitat unclear here, as it lacks species reference, but it also lacks an understanding of scale. A great challenge associated with maintaining ecosystem function through time, including succession, includes pondering the ideology and practice of Wilderness. We will explore challenges of early successional forest management in areas where a hands-off approach is legally mandated by either the state, New York Forever Wild lands, or federal government (Wilderness Preservation Act). Further, we will bring forth challenges of the this “hands-off” approach to management in heavily altered and potentially degraded ecosystems where a hands-on approach is arguably needed. Ultimately, these concepts will challenge the mandates of these Wilderness and Wild areas and highlight shortfalls of their historical underpinnings as they cannot provide habitat, when the term is used correctly, for each species – some species we legally or ethically aim to protect.
11:30AM Habitat: Next Steps on Moving TWS and the Wildlife Profession Forward
  Keith Norris
The Wildlife Society’s mission is to inspire, empower and enable wildlife professionals to sustain wildlife populations and their habitats through science-based management. To fulfill that mission, TWS serves as a forum for discussing and addressing challenges among the wildlife profession. As we highlight in this session, there are many facets to the term “habitat,” and the talks in this session emphasize many areas for additional consideration. As a professional organization TWS can explore these areas using existing mechanisms and opportunities within the Society to facilitate discussion and guide the profession on proper uses of the term “habitat” and in application to agency policies and decision-making processes. TWS’ policy statements, magazine, and other publications provide direct avenues by which to continue the discussion about the proper use of the term “habitat” among the profession, and also opportunities for the Society to lead by example. Our robust membership and organization units, such as the College and University Education Working Group, provide ample opportunities to continue the discussion and help tackle the complexity of “habitat” and its application in wildlife conservation communications. The effectiveness of TWS as a discussion forum that can help advance the profession is indeed predicated on the dedication and expertise of members – this talk will highlight mechanisms for increased engagement on the issue of “habitat” terminology.

 
Organizers: Bruce Hollen, Katie Moriarty, Terra Rentz
 
Supported by: NCASI, Inc. and the College and University Education Working Group

Symposium
Location: Reno-Sparks CC Date: October 1, 2019 Time: 8:00 am - 11:50 am