Clinical signs of health, disease, and trauma were collected as part of a long-term research program on Agassiz’s desert tortoises (Gopherus agassizii) at a 7.77 square km plot at the fenced Desert Tortoise Research Natural Area in the western Mojave Desert, USA. Surveys for health, infectious and non-infectious diseases were initiated in 1993, because of an outbreak of infectious upper respiratory tract disease caused by Mycoplasma agassizii, M. testudineum, and possibly herpesvirus (TeHV2). The disease outbreak was discovered in 1988-1989. Moderate to severe clinical signs of upper respiratory tract disease increased over time on four surveys, from 1993 through 2012. Moderate to severe signs of shell lesions (cutaneous dyskeratosis, fungal involvement) varied significantly by year. Moderate to severe clinical signs of healed, healing or moderate trauma varied from 29.8 to 42.3 percent in all sizes of tortoises. Evidence of trauma was best predicted by size-age class of the tortoises with rates increasing as size-class increased.

To improve our understanding of health and immune function in tortoises, we evaluated both standard blood diagnostic (body condition, hematologic, plasma biochemistry values, trace elements, plasma proteins, vitamin A levels) and gene transcription profiles in 21 adult tortoises (11 clinically abnormal; 10 clinically normal) from Clark County, NV, USA. Necropsy and histology evaluations from clinically abnormal tortoises revealed multiple physiological complications, with moderate to severe rhinitis or pneumonia being the primary cause of morbidity in all but one of the examined animals. Improved methods for health assessments are an important element of monitoring tortoise population recovery and can support the development of more robust diagnostic measures for ill animals, or individuals directly impacted by disturbance.

To improve our understanding of health and immune function in tortoises, we evaluated both standard blood diagnostic (body condition, hematologic, plasma biochemistry values, trace elements, plasma proteins, vitamin A levels) and gene transcription profiles in 21 adult tortoises (11 clinically abnormal; 10 clinically normal) from Clark County, NV, USA. Necropsy and histology evaluations from clinically abnormal tortoises revealed multiple physiological complications, with moderate to severe rhinitis or pneumonia being the primary cause of morbidity in all but one of the examined animals. Improved methods for health assessments are an important element of monitoring tortoise population recovery and can support the development of more robust diagnostic measures for ill animals, or individuals directly impacted by disturbance.

During a long-term study at the Desert Tortoise Research Natural Area in the western Mojave Desert of California, factors affecting the decline of desert tortoises were evaluated inside the protective fence vs. outside. During the five-survey years, 1,645 sightings of 13 species of avian predators were collected. Eleven species occurred both inside and outside the fenced Desert Tortoise Research Natural Area, and two species, the short-eared owl and great horned owl, occurred only inside the fence. The most abundant predator was the common raven with more observations outside the fence than inside the fence in most years. Ravens are hyper-predators of the desert tortoise and, at the Desert Tortoise Research Natural Area, are one of four drivers of population decline. This species also inhibits recovery because of the high numbers (Berry et al. 2020, Wildlife Monographs 205:1-53). References: Berry, K.H., Yee, J.L., Shields, T.A. and Stockton, L., 2020. The Catastrophic Decline of Tortoises at a Fenced Natural Area. Wildlife Monographs, 205(1), pp.1-53.

The database on shell-skeletal remains from 1980 through 2012 was collected as part of a monograph covering the desert tortoise populations inside and outside the fenced Desert Tortoise Research Natural Area during a period of population decline. The principal objectives of the study were to compare trends in demographic and habitat data inside the protective fence with those outside the fence. Populations and habitat outside the fence were unprotected from recreational vehicle use and sheep grazing. Data for each shell-skeletal remain found on the long-term, 7.77 square kilometers plot, included carcass number, previous number as a live tortoise, date of collection, date last observed if marked; known or estimated size, and sex, amount or totality of remains (scutes and bones), estimated time since death, location in the environment, and relationship (if any) to anthropogenic impacts or non- human predators or scavengers, and causes of death.

The database on shell-skeletal remains from 1980 through 2012 was collected as part of a monograph covering the desert tortoise populations inside and outside the fenced Desert Tortoise Research Natural Area during a period of population decline. The principal objectives of the study were to compare trends in demographic and habitat data inside the protective fence with those outside the fence. Populations and habitat outside the fence were unprotected from recreational vehicle use and sheep grazing. Data for each shell-skeletal remain found on the long-term, 7.77 square kilometers plot, included carcass number, previous number as a live tortoise, date of collection, date last observed if marked; known or estimated size, and sex, amount or totality of remains (scutes and bones), estimated time since death, location in the environment, and relationship (if any) to anthropogenic impacts or non- human predators or scavengers, and causes of death.

We developed a model for analyzing multi-year demographic data for long-lived animals and used data from a population of Agassiz’s desert tortoise (Gopherus agassizii) at the Desert Tortoise Research Natural Area in the western Mojave Desert of California, USA, as a case study. The study area was 7.77 square kilometers and included two locations: inside and outside the fenced boundary. The wildlife-permeable, protective fence was designed to prevent entry from vehicle users and sheep grazing. We collected mark-recapture data from 1,123 tortoises during 7 annual surveys consisting of two censuses each over a 34-year period. We used a Bayesian modeling framework to develop a multistate Jolly-Seber model because of its ability to handle unobserved (latent) states and modified this model to incorporate the additional data from non-survey years. For this model we incorporated 3 size-age states (juvenile, immature, adult), sex (female, male), two location states (inside and outside the fenced boundary) and 3 survival states (not-yet-entered, entered/alive, and dead/removed). We calculated population densities and estimated probabilities of growth of the tortoises from one size-age state to a larger size-age state, survival after 1 year and 5 years, and detection. Our results show a declining population with low estimates for survival after 1 year and 5 years. The probability for tortoises to move from outside to inside the boundary fence was greater than for tortoises to move from inside the fence to outside. The probability for detecting tortoises differed by size-age state and was lowest for the smallest tortoises and highest for the adult tortoises. The framework for the model can be used to analyze other animal populations where vital rates are expected to vary depending on multiple individual states. The model was incorporated into the manuscript that included several other databases for publication in Wildlife Monographs in 2020 by Berry et al.

We developed a model for analyzing multi-year demographic data for long-lived animals and used data from a population of Agassiz’s desert tortoise (Gopherus agassizii) at the Desert Tortoise Research Natural Area in the western Mojave Desert of California, USA, as a case study. The study area was 7.77 square kilometers and included two locations: inside and outside the fenced boundary. The wildlife-permeable, protective fence was designed to prevent entry from vehicle users and sheep grazing. We collected mark-recapture data from 1,123 tortoises during 7 annual surveys consisting of two censuses each over a 34-year period. We used a Bayesian modeling framework to develop a multistate Jolly-Seber model because of its ability to handle unobserved (latent) states and modified this model to incorporate the additional data from non-survey years. For this model we incorporated 3 size-age states (juvenile, immature, adult), sex (female, male), two location states (inside and outside the fenced boundary) and 3 survival states (not-yet-entered, entered/alive, and dead/removed). We calculated population densities and estimated probabilities of growth of the tortoises from one size-age state to a larger size-age state, survival after 1 year and 5 years, and detection. Our results show a declining population with low estimates for survival after 1 year and 5 years. The probability for tortoises to move from outside to inside the boundary fence was greater than for tortoises to move from inside the fence to outside. The probability for detecting tortoises differed by size-age state and was lowest for the smallest tortoises and highest for the adult tortoises. The framework for the model can be used to analyze other animal populations where vital rates are expected to vary depending on multiple individual states. The model was incorporated into the manuscript that included several other databases for publication in Wildlife Monographs in 2020 by Berry et al.

During a multi-year demographic study of Agassiz’s desert tortoise (Gopherus agassizii) at the Desert Tortoise Research Natural Area (Natural Area), in the western Mojave Desert, USA, we recorded evidence of evidence of mesocarnivores that commonly prey on desert tortoises on a 7.77 square-kilometer study area. The study area included land inside and outside the fenced boundary of the Natural Area. We recorded locations, condition and recency of sign, and type of sign present at burrows, dens, and den complexes used by desert kit foxes (Vulpes macrotis), coyotes (Canis latrans), American badgers (Taxidea taxus), and bobcats (Lynx rufus). We also recorded scat piles by species using them, amount, and relative ages of the scats. Scats were checked for evidence of desert tortoise remains. Observations of live mesocarnivores were noted also. We compared differences in predator pressure inside and outside the boundary fence of the Natural Area and whether mesocarnivores were a driver for changes in tortoise demography.

Data on annual and perennial plants were collected during four survey years (1989, 1993, 1997, and 2012) at a 7.77 sq. km the Desert Tortoise Research Natural Area in the western Mojave Desert as part of a long-term research project on populations and habitat of the threatened desert tortoise (Gopherus agassizii) spanning 34 years. The data collection and analysis involved comparisons of vegetation inside and outside the fenced Desert Tortoise Research Natural Area.