Vocabulary:

• Landscape ecology: the study of the composition, structure & function of the landscape
• Spatial heterogeneity: different spatial patterns of the elements that make up the landscape, and the processes that give rise to those patterns
• Ecotone: a broad transition zone between adjoining patches
• Metapopulations: a set of local populations occupying habitat patches, connected to one another by the movement of individuals
• Patches: areas of habitat suitable for a species of interest
• Matrix: the surrounding landscape in which patches of suitable habitat are embedded
• Boundary or Edge: the perimeter of a patch
• Corridor: a narrow strip of habitat that connects two patches
• Isolation: the distance from neighboring patches
• Core Area: the interior of a patch where resources are more abundant
• Natural Disturbances: disruptions to landscapes caused by fire, flooding, earthquakes, etc.

Outline of Notes:

Every landscape has features that make them unique and appealing to different plants and animals. Areas of habitat can be divided into patches, matrices, edges, and corridors. The proportion of each of these components can determine which types of species inhabit the area.

Anatomy of a Fragmented Landscape:

• Patch: suitable, relatively undisturbed animal habitat that is secluded from other habitats via boundaries.
  

  

• • Characteristics of distinct patch types:
    • Different land type
    • Species composition
    • Succession
    • Differing levels of disturbance
  • Based on the size of study organism
• Larger patches have larger core areas
  • Core Areas: the interior of a patch where resources are more abundant
• Matrix: considered the ‘background’ ecological system that has a high degree of connectivity, compared to the patches within it.
• Boundary: the perimeter of patches; also called the “Edge”
• Corridor: a connection between patches that allows individuals to pass through a matrix; not always a permanent fixture in the landscape

Habitat Patches:

• Patchiness: a way of describing the availability, size, and connectivity of a suitable habitat within a given landscape

• Causes of Patchiness:

1. 1. Climate: locations with specific climatic conditions can cause a patch, like an oasis in a desert, or the desert itself.
   2. Geology: Mountains, valleys, and other geological boundaries
   3. Topography: Any topographical boundary created by a body of water: rivers, streams, lakes, or oceans
   4. Disturbance (natural or anthropogenic):

• • • Natural disasters (ex: wildfires, hurricanes)
    • Human behaviors and our infrastructure is perhaps the most common creator of patches:
      • Roads can create impassable boundaries for most creatures
      • We create patches of habitat (parks and gardens) in otherwise unsuitable urban areas

• Desirability of patches depends upon:
  • Resource concentration
  • Species diversity
  • Number of available niches
  • Climate patterns
  • Ground cover
  • Size of the patch and/or amount of edge
  • Anthropogenic effects

Boundaries and Edge Habitats:

• Boundaries can vary significantly in length, width, height, and porosity (how easily species can pass through)
• They allow for the transfer of material, energy, and organisms between patches
  • Some boundaries may restrict or facilitate dispersal, depending on the conditions and species
• They can be abrupt distinct places where the landscape changes, or transition slowly over the landscape forming
  ecotones
  • Ecotone: A broad transition zone between adjoining patches
• A diversity of environmental conditions may support the colonization of new plant and animal species
• Effects of habitat fragmentation:
  • Edge habitat increases while interior habitat decreases
  • Edge species increase while interior species decrease

• Species that live in edge habitat may be:
  • Animals whose requirements vary with…
    • Age, sex, required resources, or ideal habitat type
  • Or plants that can tolerate:
    • High light levels, dry conditions, or high temperatures
  • Species that are favored by disturbance, such as:
    • Invasives, pioneers, r-strategists, or generalists

Metapopulation Dynamics:

• As habitats become fragmented, metapopulations are formed
  • Metapopulations: A set of local populations occupying habitat patches, connected to one another by the movement of individuals
• As patch size increases, rates of extinction decrease
• As patches become more isolated, rates of colonization decrease as it becomes more difficult for species to disperse
• Changes in rates of extinction and colonization affect the proportion of occupied patches

Graph

 Blog Style Summary:

What do butterflies, coconuts, and salamanders have in common? They are all metapopulations that have been separated as a result of landscape ecology.

When someone talks to you about a metapopulation you probably think of a massive population of species. You are right to an extent- a metapopulation is a population of populations within a landscape. Metapopulations usually have different landscapes that are connected by corridors. That’s when landscape ecology comes into play. Landscape ecology is the study of the composition, structure, and function of the landscape. According to the article by Howell et al. (2018), landscape ecology is “understanding how spatial structure influences ecological processes”. Natural disturbances, such as floods, are one way in which spatial structures are changed and metapopulations are formed.

Floods are a frequent occurrence across the coastal plains of North Carolina, the native range of the Eastern tiger salamander (Ambystoma tigrinum) (Figure 1.). If a flash flood isolated a portion of the salamander population, it would become a metapopulation. Once the flood waters begin to recede, corridors form between the metapopulations. This facilitates travel between the metapopulations that were previously isolated. These corridors connect suitable niches or “patches” where the salamanders have access to adequate resources. The movement of organisms from one patch to another is known as dispersal.

So what exactly does a ‘patch’ look like? A patch of suitable habitat for one organism might not be a patch for another. In the case of the salamanders, their patches are coastal plains surrounded by water (the matrix). This might not be desirable for other organisms, like birds, who might require forested areas for nesting and foraging. Patches are defined by their boundaries, which are surrounded by the matrix. Boundaries (or edges) come in all different shapes and sizes. They can be very narrow and have sharp transitions between different habitat types, or they can be wide and gradually change between habitat types, providing a “buffer zone” or ecotone. Boundary (or edge) habitats are a highly disturbed zone, and because of this, they favor organisms that can tolerate a wide range of environmental conditions.

Figure 2. Patch-Matrix Graphic.

The eastern tiger salamander might be considered an edge species, due to its semi-aquatic lifestyle. It can live on the edge of a body of water and strip of land, whereas other species, called interior species, require large, uninterrupted areas of interior habitat and cannot survive well in edge habitats.

Interior species are highly susceptible to habitat loss and fragmentation. The Florida black bear is an interior species that has had much of its suitable habitat reduced due to human expansion. This species was once abundant in the southeastern United States, but now has only a few populations scattered across much smaller, fragmented, and isolated patches. Scientists are now making efforts to create effective corridors for this species, which is an example of how metapopulation dynamics can be used to promote conservation (Dixon et al., 2006).

You might be asking what’s the difference between metapopulations and landscape ecology, as it sounds like they go hand in hand. However, metapopulation ecology models tell you how the spatial distribution of the patches affects colonization and extinction, whereas landscape ecology models use detailed descriptions of landscape structures (Howell et al. 2018).

To summarize, metapopulations are small populations that have been separated from the original population by landscape ecology. The spatial distribution of the metapopulations within a matrix are dependent on patches and dispersal patterns. Some species prefer using corridors to transit between patches, while others don’t care which patch they’re in. Different species can be characterized by the patches they inhabit and can be referred to as either ‘edge-species’ or ‘interior species.’ The topic of metapopulations and landscape ecology is an important one for conservation efforts as humans continue to urbanize land and fragment natural habitats.

 Spotlight on NC:

Red Wolves: Restoring a Species

Red wolves (Canis rufus) are wolves that were once found across the Southeastern United States. About 4 feet long, they have reddish coats with gray and black highlights and a black tail. Smaller than gray wolves and larger than coyotes, 400 wild red wolves existed in 1970 before they became functionally extinct in the 1980s. Reintroduced red wolves are the world’s most endangered canid with a range spanning the Albemarle Peninsula of North Carolina, a minuscule fraction of their historical range. Historically, red wolves roamed across the southeast, from central Texas to Florida and as far north as New York [1].
 The drastic decline of this species is due to the fragmentation of their natural woodland habitats, which has separated populations and limited dispersal. Like gray wolves, they form packs based on family relationships and defend their 20-80 mi² territory from other canids. Unlike gray wolves, their packs are much smaller and consist of a mated pair and their 5-6 pups [1]. Due to the lack of suitable habitats, the ecological density of red wolves has suffered a steep decline, causing a lack of survivorship of the species.
Predator-prey interactions have become disrupted due to human interference, as humans shoot the wolves to protect their livestock and game, further contributing to their decline [1]. The remaining red wolves have struggled to maintain a healthy population density, forcing them to change their mating behaviors and hybridize with coyotes and gray wolves (https://doi.org/10.1111/conl.12157).

 Efforts to recover the red wolf population are headed by the U.S. Fish and Wildlife Service through the Red Wolf Recovery Program (RWRP). In the fall of 2020, a court order mandated that eight red wolves be released into the wild. The Southern Environmental Law Center (SELC) believed that this low number of red wolves being released was in violation of the Endangered Species Act and sued the U.S. Fish and Wildlife Service for their lack of action [2]. In July of 2021, the RWRP was updated for the first time in thirty-one years. The new plan consists of a species status assessment, a recovery plan, and a recovery implementation strategy [3]. The Red Wolf Recovery Program has paved the way for successful captive breeding and reintroduction initiatives beyond just red wolves. Recovery programs for other endangered species have implemented tactics first used for the red wolves. The RWRP pays close attention to managing genetic diversity amongst the growing captive population by rotating the captive wolves across the different facilities [3]. It is important that the captive breeding can be representative of a diverse population to ensure that the red wolves can actually survive environmental shifts and challenges once reintroduced into their natural habitats. The program also aims to limit interactions between handlers and wolves in captivity to promote a healthy and natural pack structure and help deter the wolves from approaching humans after release.

Currently, the Red Wolf Recovery Program utilizes radio collars on adult wolves to track movement and overall population changes of red wolves in their only known wild habitat. This known population is spread over five NC counties of the Albemarle Peninsula [3]. The peninsula is a compilation of many patches that range from small to large in size. The largest patch is the Alligator River National Wildlife Refuge in Dare County. The refuge has a fragmented corridor that spans through Hyde and Tyrell County into the Pocosin Lakes National Wildlife Refuge. This area was chosen because of the low abundance of coyotes in the area and low human population relative to the rest of NC. Choosing an area with a low human population was crucial to minimize interactions between the wolves, humans, and livestock. Per the 10(j) experimental population classification assigned to the wolves in 1995, they cannot be removed from the area unless it is first demonstrated that the wolf is a threat to human, livestock, or pet safety [1].

While the Albemarle may seem like a perfect habitat, the peninsula is surrounded by the Albemarle and Pamlico Sounds and many small water inlets cutting into the land. This type of landscape ecology could decrease overall connectivity and have a negative impact on the potential for the red wolf population to thrive. Furthermore, the three main patches that contain the wolf population are separated and do not have fully connected corridors to allow for gene flow. This adds to the growing concern of roaming red wolves finding their way into human-inhabited areas that have expanded since the recovery program started. However, the wolves have come a long way since their reintroduction. If we want to continue their progress, then wildlife corridors will be crucial to their survival.

The Red Wolf Restoration program is nationally renowned as a model for metapopulation ecology. The few patches that cover the Albemarle Peninsula are a model for future endangered species recovery programs. Right now, captive wolf populations are rotated throughout the enlisted conservation facilities where they are heavily managed, but future recovery efforts will aim to limit human interaction. Going forward, the Red Wolf Recovery Program will continue to monitor and advocate for the protection of the red wolf population.

Live Red Wolf Webcam:

https://nywolf.org/meet-our-wolves/webcams/webcam-red-wolves-charlotte-jack-family/

Featured Ecologists:

David Eggleston, Phd

Dr. David Eggleston’s research focuses on testing, refining, and applying general ecological concepts to marine systems. The goal of his research is to improve the understanding of ecological processes in marine ecosystems and to apply them to sustainable management techniques. In order to achieve this understanding, he conducts field observations, experiments, computer simulation modeling, and geochemical and molecular tools. Eggleston researches metapopulations, species interactions, and community ecology. His most recently published article in 2021 is titled Metapopulation dynamics of oysters: sources, sinks, and implications of conservation and restoration. A few of the findings of this article include the decline of oyster populations, reef-specific population trajectories that are dependent on spatiotemporal variation for larval recruitment, inter-reef larval connectivity on metapopulation dynamics are more important than the local larval retention process, and that spatiotemporal variation in the source-sink status of subpopulations. This research reaffirmed that oyster reefs need to be continually protected and managed. This research is important for understanding how to best conserve marine ecosystems, particularly in the context of warming ocean temperatures due to climate change.

Mona Papeş, PhD

Dr. Mona Papeş uses remote sensing and GIS data in order to understand the anthropogenic effects on the environment, and consequently the effects on the species distributions. In her research, her hope is to apply local-scale environmental predictors to broad-scale estimations of biodiversity. She uses niche modeling to predict future species distributions and niches.  Papeş studies a broad range of species in order to better understand and model population distributions. She examines concepts such as species distribution and understanding species’ niches in relation to the geographical distribution of the ecosystem.  She uses remote sensing as well as GIS in order to model her findings. Her dissertation focused on the applications of remote sensing in neotropical rainforests, through the examination of frugivore species and the characteristics of the fruit trees that act as resources for them. She found that tree spectra varied temporally, and her research indicated that it is possible to study trees through remote sensing. In her research, she has found that regardless of what climate change scenario, it is likely that species distributions are estimated to shift. Through her research, she is able to better understand seasonal variation in species distribution. The implications of her research allow others to gain insight into species biodiversity and niche resiliency to anthropogenic effects, allowing others to formulate more beneficial conservation and mitigation strategies.

Frank Van Manen, Phd

Since 2006, Dr. van Manen has focused his research on the grizzly bears of Yellowstone National Park. His work has been essential in the classification of these species as endangered and retaining their federal/state protection. Recently Dr. van Manen has also been looking at how the bear populations (both brown and black) interact with the gray wolves of the park and how the species are coexisting and affecting each other. Prior to working with the grizzly bears, Dr. van Manen worked on research teams that worked to conserve and protect giant pandas in China, as well as sloth bears in Sri Lanka and Andean (spectacled) bears in the Andes Mountains. Dr. van Manen also worked with American black bears during his time at the University of Tennessee-Knoxville, where he further explored his interest in how landscape ecology can affect populations and vice versa.

Student contributors:

Note Outline: Cheyana Bassham, Leo Kerner, Alexa Ouellette, Claire Waters, Robert Whiting

Blog Style Summary: Malia Naumchik, Sydney Kuczenski, Dustin Bigford, Dawson Bigford

Spotlight on NC: Shomari Presswood, Sarah Rachita, Chip Ralph, Breana Lavallee

Featured Ecologists: Jordan Reimers, Helena Jolly, Alexa Ouellette