conservation.arizona.edu - habitat

Paudel, S., P. Pal, M. V. Cove, S. R. Jnawali, G. Abel, J. L. Koprowski, and R. Ranabhat. 2015. The endangered Ganges River dolphin Plantanista gangetica gangetica in Nepal: abundance, habitat and conservation threats. Endangered Species Research 29:59-68

thackerk1 — Wed, 24 Jul 2019 23:15:36 +0000

Authors

Shambhu Paudel

Prabhat Pal

Michael V. Cove

Shant Raj Jnawali

Grant Abel

John L. Koprowski

Rishi Ranabhat

Conservation of the last remaining Ganges River dolphins Platanista gangetica gangetica in Nepal will require robust population estimates and better information on suitable habitat characteristics. To gain a better understanding of these parameters, we conducted boat- based surveys in the 3 major river systems (Karnali, Sapta Koshi, and Narayani) of Nepal. We recorded covariates at high spatial resolution and utilized these data to inform occurrence and abundance models. We allowed for detection bias by applying occupancy and N-mixture models that account for imperfect and heterogeneous detection. Occupancy results indicate that dolphin site use varies among the different river systems, across 2 seasons, and increases with river depth. River effects received nearly 100% of the model support and had the strongest influence on dolphin occurrence and abundance. The seasonal influence on dolphin occurrence in the systems (Σωi = 0.997) revealed that occupancy probabilities were heightened during the pre-monsoon season. Deep pool habitat was also identified as a predictor of dolphin habitat use, which accounted for 41.02% of all dolphin sightings occurring in this habitat. Although estimates vary depending on season, we estimate that there are between 37 and 42 (95% CI: 28 to 52) Ganges River dolphins distributed in the rivers of Nepal. Results suggest that seasonality and each specific river affect dolphins and their habitat in Nepal; we strongly recommend site and season-specific conservation actions. Further research on the integration of additional and alternative abundance techniques, behavioral studies, and pursuit of a conservation genetics approach are all important steps in the management of this endangered species.

Additional Information

The Endangered Ganges River dolphin Platanista gangetica gangetica in Nepal: abundance, habitat and conservation threats

Date of publication:

2015

Topics

Ganges River dolphin

habitat

distribution

Nepal

Endangered species

Merrick, M. J., J. L. Koprowski, and C. Wilcox. 2013. Into the third dimension: Benefits of incorporating LiDAR into wildlife habitat models. In Gottfried, Gerald J.; Ffolliott, Peter F.; Gebow, Brooke S.; Eskew, Lane G.; Collins, Loa C., comps. 2013. Mer

thackerk1 — Tue, 23 Jul 2019 23:28:02 +0000

Authors

Melissa J. Merrick

John L. Koprowski

Craig Wilcox

LiDAR (Light detection and ranging) is a tool with potential for characterizing wildlife habitat by providing detailed, three-dimensional landscape information not available from other remote sensing applications. The ability to accurately map structural components such as canopy height, canopy cover, woody debris, tree density, and ground surface has potential to improve wildlife habitat models because animals interact and respond to three-dimensional habitat features. Prior to LiDAR, accurate measurements of structural features were difficult to obtain over large areas as other remote sensing data are based on two-dimensional spectral responses. The Southwest harbors a large diversity of unique vegetation communities, each with an associated wildlife assemblage with various management needs. Managers can use LiDAR to accurately characterize vegetation and landscape structural characteristics for entire districts or management units. Data surfaces derived from the LiDAR point cloud can be readily incorporated into species-specific or multispecies habitat models. Although LiDAR has received much attention in characterizing forest structure, fewer studies (n = 29) have suggested or incorporated this technology to improve wildlife habitat models specifically. Herein we provide a review of current LiDAR applications in wildlife habitat models, provide future directions, and detail how LiDAR can increase our ability to represent the world that animals experience.

Additional Information

Into the Third Dimension: Benefits of Incorporating LiDAR Data in Wildlife Habitat Models

Date of publication:

2013

Topics

LiDAR

habitat

habitat models

Koprowski, J. L., S. L. Doumas, M. J. Merrick, B. Oleson, E. E. Posthumus, T. G. Jessen, and R. N. Gwinn. 2013. It's lonely at the top: Biodiversity at risk to loss from climate change. In Gottfried, Gerald J.; Ffolliott, Peter F.; Gebow, Brooke S.; Eskew

thackerk1 — Mon, 22 Jul 2019 21:36:58 +0000

Authors

John L. Koprowski

Sandra L. Doumas

Melissa J. Merrick

Brittany Oleson

Erin E. Posthumus

Timothy G. Jessen

R. Nathan Gwinn

Climate change is a serious immediate and long-term threat to wildlife species. State and federal agencies are working with universities and non-government organizations to predict, plan for, and mitigate such uncertainties in the future. Endemic species may be particularly at-risk as climate-induced changes impact their limited geographic ranges. The Madrean Archipelago is characterized by high levels of endemism, natural fragmentation, and increasingly poor connectivity among the mesic montane islands within an arid matrix of low elevation deserts and grasslands. The region already has experienced an increase in temperature and this trend is predicted to accelerate over the remainder of the century. We assessed patterns of elevational distribution of reptiles and mammals within the Madrean Archipelago. We examined incremental temperature increases and determined how much reptilian and mammalian biodiversity is at-risk to be lost from montane islands due to elevational and geographic restriction. We estimate that 15 to 20% of all reptile and mammal diversity is at risk of loss by 2100 based solely on predicted patterns of upslope migration of biotic communities driven primarily by climate change. With this significant proportion of native species, we suggest that this emphasizes the need to continue traditional management actions focused on habitat improvement, restoration and connectivity for the majority of species in combination with innovative and active management strategies directed at the subset that is most at risk of extirpation.

Additional Information

It’s Lonely at the Top: Biodiversity at Risk to Loss from Climate Change

Date of publication:

2013

Topics

climate change

endemic species

geographical range

biodiversity

Madrean Archipelago

restoration

habitat

connectivity

Differential response of native Arizona gray squirrels and introduced Abert's squirrels to a mosaic of burn severities

thackerk1 — Mon, 22 Jul 2019 21:22:42 +0000

Authors

Shari L. Ketcham

John L. Koprowski

Donald A. Falk

Disturbance events can alter habitat properties, leading to species displacement, isolation, and/or local extinction. Therefore, understanding the interactions of potential ecological drivers on native and introduced wildlife species post-fire is critical to understand influences on distribution. We studied native Arizona gray squirrels (Sciurus arizonensis), which are believed to favor dense riparian habitat, and introduced Abert’s squirrels (S. aberti), which prefer open ponderosa pine (Pinus ponderosa) forests. We examined how uncommon native Arizona gray squirrels and introduced Abert’s squirrels used areas previously burned by widespread fires more than a decade prior to our study. To determine how past fire may affect squirrel habitat, we examined squirrel use and occupancy within fire altered habitats and used distance sampling to determine squirrel distribution, feeding, and nest use within a mosaic of burn severities. Occupancy and habitat use indicated that introduced Abert’s squirrels readily used post-fire conditions more than native Arizona gray squirrels, likely due to the opening of a dense understory. Arizona gray squirrels remained in unburned riparian areas; therefore, fire affected riparian areas can be directly targeted for management to increase abundance of the native species.

Additional Information

Mammal Study 42:247-258.

Date of publication:

2017

Topics

Arizona gray squirrel

Abert’s squirrels

ponderosa pine

wildfire effects

occupancy

habitat

feeding signs

dreys

Research Categories

Disturbance Ecology Sky Islands Threatened and Endangered Species

Doumas, S.L., J.L. Koprowski. 2013. Return of fire as a restoration tool: long-term effects of burn severity on habitat use by Mexican fox squirrels. Restoration Ecology 21:133-139.

thackerk1 — Tue, 25 Jun 2019 00:43:39 +0000

Authors

Sandra L. Doumas

John L. Koprowski

After decades of suppression, fire is returning to forests of the western United States through wildfires and prescribed burns. These fires may aid restoration of vegetation structure and processes, which could improve conditions for wildlife species and reduce severe wildfire risk. Understanding response of wildlife species to fires is essential to forest restoration because contemporary fires may not have the same effects as historical fires. Recent fires in the Chiricahua Mountains of southeastern Arizona provided opportunity to investigate long-term effects of burn severity on habitat selection of a native wildlife species. We surveyed burned forest for squirrel feeding sign and related vegetation characteristics to frequency of feeding sign occurrence. We used radio-telemetry within fire- influenced forest to determine home ranges of Mexican fox squirrels, Sciurus nayaritensis chiricahuae, and compared vegetation characteristics within home ranges to random areas available to squirrels throughout burned conifer forest. Squirrels fed in forest with open understory and closed canopy cover. Vegetation within home ranges was characterized by lower understory density, consistent with the effects of low-severity fire, and larger trees than random locations. Our results suggest that return of low-severity fire can help restore habitat for Mexican fox squirrels and other native wildlife species with similar habitat affiliations in forests with a historical regime of frequent, low-severity fire. Our study contributes to an understanding of the role and impact of fire in forest ecosystems and the implications for forest restoration as fire returns to the region.

Additional Information

Return of Fire as a Restoration Tool: Long‐Term Effects of Burn Severity on Habitat Use by Mexican Fox Squirrels

Date of publication:

2012

Topics

Chiricahua fox squirrel

prescribed fire

wildfire

habitat

home range

vegetation

Cudworth, N.L., J.L. Koprowski. 2011. Importance of scale in nest-site selection in Arizona gray squirrels. Journal of Wildlife Management. 75: 1668–1674

thackerk1 — Mon, 24 Jun 2019 23:02:55 +0000

Authors

Nichole L. Cudworth

John L. Koprowski

Nests provide a place for individuals to rest, raise young, avoid predators, and escape inclement weather; consequently, knowledge of habitat characteristics important to nest placement is critical for managing species of conservation concern. Arizona gray squirrels (Sciurus arizonensis) are endemic to mountains of southwestern United States and northwestern Mexico. We investigated factors influencing nest-site selection at 4 spatial scales (forest-type, nest-site, nest-tree, and within-canopy placement) to provide ecological information and management recommendations for this sensitive species. Nest densities were 2.6 times higher in riparian than pine-oak woodlands. Nest sites had more large trees, snags, logs, and canopy cover and had lower slope. Arizona gray squirrels selected tall trees with more interlocking trees and tended to place nests adjacent to the main trunk. Regardless of scale, Arizona gray squirrels seemed to select nesting areas for their ability to provide protection from predators and the elements as well as access to food. Consequently, maintaining large trees with closed canopies and downed logs should be considered when determining land management plans. ©2011 The Wildlife Society.

Additional Information

Importance of Scale in Nest-Site Selection by Arizona Gray Squirrels

Date of publication:

2011

Topics

Arizona gray squirrel

habitat

drey

Brown, D. E., R. D. Babb, C. Lorenzo, and M. M. Altemus. 2014. Ecology of the antelope jackrabbit (Lepus alleni). The Southwestern Naturalist 59:575-587.

thackerk1 — Thu, 20 Jun 2019 22:39:48 +0000

Authors

David E. Brown

Randall D. Babb

Consuelo Lorenzo

Maria M. Altemus

The antelope jackrabbit (Lepus alleni) is a lagomorph indicative of Neotropic savanna and thornscrub in south-central Arizona, west-central Sonora, and western Sinaloa <1,200 m elevation. We found populations in Arizona are most abundant in tropic–subtropic areas of low relief, characterized by velvet mesquite (Prosopis velutina) with an herbaceous understory (= Sonoran savanna grassland), and receiving a mean annual rainfall of between 200 and 450 mm, >90 mm of which falls as summer precipitation. In Mexico, this hare most commonly occurred in savanna grasslands or thornscrub interrupted by open areas receiving between 200 and 450 mm of precipitation per annum. Cacti were important habitat components for the hares and mean annual temperatures were >18°C with <60 d a year having temperatures below 0°C. Although sympatric with Lepus californicus over portions of its range, the two species preferred different habitats and rarely occurred together, and L. alleni was more prone to occur in groups than was L. californicus. We calculated the distributional range of L. alleni as ca. 102,000 km2 in Arizona and Mexico.

Additional Information

Ecology of the antelope jackrabbit

Date of publication:

2014

Topics

antelope jackrabbit

annual rainfall

lagomorph

habitat

cacti

distributional range